Revisiting the Problem of Searching on a Line

We revisit the problem of searching for a target at an unknown location on a line when given upper and lower bounds on the distance D that separates the initial position of the searcher from the target. Prior to this work, only asymptotic bounds were known for the optimal competitive ratio achievable by any search strategy in the worst case. We present the first tight bounds on the exact optimal competitive ratio achievable, parameterized in terms of the given bounds on D, along with an optimal search strategy that achieves this competitive ratio. We prove that this optimal strategy is unique. We characterize the conditions under which an optimal strategy can be computed exactly and, when it cannot, we explain how numerical methods can be used efficiently. In addition, we answer several related open questions, including the maximal reach problem, and we discuss how to generalize these results to m rays, for any m >= 2

Investigation into the effect of Si doping on the performance of SrFeO3-δ SOFC electrode materials

In this paper we report the successful incorporation of silicon into SrFeO3-δ perovskite materials for potential applications as electrode materials for solid oxide fuel cells. It is observed that Si doping leads to a change from a tetragonal cell (with partial ordering of oxygen vacancies) to a cubic one (with the oxygen vacancies disordered). Annealing experiments in 5% H2/95% N2 (up to 800 °C) also showed the stabilization of the cubic form for the Si-doped samples under reducing conditions, suggesting that they may be suitable for both cathode and anode applications. In contrast to the cubic cell of the reduced Si doped system, reduction of undoped SrFeO3-δ leads to the formation of a brownmillerite structure with ordered oxide ion vacancies. SrFe 0.90Si0.10O3-δ and SrFe 0.85Si0.15O3-δ were analysed by neutron powder diffraction, and the data confirmed the cubic cell, with no long range oxygen vacancy ordering. Mössbauer spectroscopy data were also recorded for SrFe0.90Si0.10O3-δ, and indicated the presence of only Fe3+ and Fe5+ (i.e. disproportionation of Fe4+ to Fe3+ and Fe5+) for such doped samples. Conductivity measurements showed an improvement in the conductivity on Si doping. Composite electrodes with 50% Ce0.9Gd0.1O 1.95 were therefore examined on dense Ce0.9Gd 0.1O1.95 pellets in two different atmospheres: air and 5% H2/95% N2. In both atmospheres an improvement in the area specific resistance (ASR) values is observed for the Si-doped samples. Thus the results show that silicon can be incorporated into SrFeO3-δ- based materials and can have a beneficial effect on the performance, making them potentially suitable for use as cathode and anode materials in symmetrical SOFCs. © 2013 The Royal Society of Chemistry.Peer Reviewe

Anatomical and sonographic correlation of the fetal ductus arteriosus in first and second trimester pregnancy

Ultrasonic visualization of the ductus arteriosus in first and second trimester pregnancies was compared with postmortem preparations. Twenty human fetal postmortem specimens from 8 to 19 weeks menstrual age were examined, 11 with microscopic reconstruction, nine with macroscopic dissection. The angle between ductus arteriosus and aortic isthmus (upstream) and ductus arteriosus and descending aorta (downstream) was determined. In 52 normally developing fetuses between 14 and 27 weeks, the angle between the ductus arteriosus and the thoracic spine as visualized in real-time ultrasound was determined. In a further 19 normally developing fetuses between 14 and 25 weeks, ductal blood flow was visualized by colour velocity imaging (CVI). In anatomical preparations, the upstream angle was always less than 90° and the downstream angle was always 80° or more. These angles were unrelated to menstrual age. In both real-time and CVI ultrasound, the angle between ductus arteriosus and thoracic spine remained at approximately 90°. CVI showed highest blood flow velocities at the point of ductal insertion into the aorta. When performing Doppler ultrasound examinations in the fetal ductus arteriosus, no menstrual age dependent angle adjustment appears to be necessary

HISTORICAL AND ARCHAEOSEISMIC STUDIES IN THE POLLINO AREA

Section 1. Reappraisal of the January 8, 1693 Pollino earthquake Section 2. Archaeoseismic field survey Section 3. Investigation of damaged speleothem

Satisfaction with chronic obstructive pulmonary disease treatment: results from a multicenter, observational study

Background: Understanding the level of patients' satisfaction with treatment and its determinants have the potential to impact therapeutic management and clinical outcome in chronic conditions such as chronic obstructive pulmonary disease (COPD). Methods: A national, multicenter, longitudinal, observational study of COPD from 20 Italian pulmonary centers to explore patients' satisfaction to treatment [assessed by the Treatment Satisfaction Questionnaire, 9 items (TSQM-9)] and association with clinical parameters [including dyspnea score, COPD Assessment Test (CAT) score, exacerbation rate], adherence to treatment [Morisky Medication-Taking Adherence Scale (MMAS-4)], illness perception [evaluated by Brief Illness Perception Questionnaire (B-IPQ)] in a 1-year follow up. Results: A total of 401 COPD patients were enrolled [69.4% group B Global Initiative for COPD (GOLD), considering 366 patients with available GOLD 2017 classification at enrollment]. At enrollment, satisfaction with treatment was moderate, being TSQM-9 mean scores for effectiveness 64.2 [95% confidence interval (CI) 62.5-65.9], for convenience 75.8 (95% CI 74.2-77.3), and for global satisfaction 65.7 (95% CI 64.0-67.4). Global satisfaction was negatively associated with disease perception (beta = -0.4709, p < 0.0001), and grade of dyspnea (beta = -4.2564, p = 0.009). Satisfaction with treatment was lower in patients with poor compared with optimal adherence to treatment (beta = -4.5608, p = 0.002). Changes in inhalation regimens during follow up did not modify the satisfaction with treatment. Conclusions: The results of this real-life study showed that the patients' satisfaction with treatments is only moderate in COPD. A high grade of patients' satisfaction is associated mainly with a low perception of the disease, high adherence to treatment and lower level of dyspnea

The Electroweak Phase Transition on Orbifolds with Gauge-Higgs Unification

The dynamics of five dimensional Wilson line phases at finite temperature is studied in the one-loop approximation. We show that at temperatures of order T \sim 1/L, where L is the length of the compact space, the gauge symmetry is always restored and the electroweak phase transition appears to be of first order. Particular attention is devoted to the study of a recently proposed five dimensional orbifold model (on S1/Z2) where the Wilson line phase is identified with the Higgs field (gauge-Higgs unification). Interestingly enough, an estimate of the leading higher-loop ``daisy'' (or ``ring'') diagram contributions to the effective potential in a simple five dimensional model, seems to suggest that the electroweak phase transition can be studied in perturbation theory even for Higgs masses above the current experimental limit of 114 GeV. The transition is still of first order for such values of the Higgs mass. If large localized gauge kinetic terms are present, the transition might be strong enough to give baryogenesis at the electroweak transition.Comment: 35 pages, 34 figures; v2: discussion on higher loop contributions improved, two figures added, minor correction

Synthesis and biological evaluation as microtubule-active agents of several tetrahydrofuran and spiroacetal derivatives

The stereoselective preparation of several molecules containing structural fragments of the tetrahydrofuran and spiroacetal type is described. Their degree of cytotoxicity and their interactions with tubulin have been investigated. It has been confirmed that the tetrahydrofuran derivatives are cytotoxic but, in contrast to previous reports, it has been found that the cytoxicity is not due to interactions with the microtubule network. Furthermore, and also in contrast to a previous report on closely related compounds, the spiroacetal derivatives do show interactions with tubulin, even though the precise mechanism and the binding site still remain to be established.Financial support has been granted by the Spanish Ministry of Education and Science (CTQ2008-02800), by the Consellería d´Empresa, Universitat i Ciencia de la Generalitat Valenciana (ACOMP09/113) and by the BANCAJA-UJI Foundation (P1-1B2002-06 and P1-1B-2008-14). The biological work has been supported in part by grants from the Spanish Ministry of Education and Science (BIO2007- 61336) and from the Comunidad de Madrid (grants S2010/ BMD-2457 and BIPEDD2-CM) (both to J.F.D.). We further thank the Matadero Municipal Vicente de Lucas in Segovia for providing the calf brains which were the source of tubuli

Photo- and Electron-Production of Mesons on Nucleons and Nuclei

In these lectures I will show some results obtained with the chiral unitary approach applied to the photo and electroproduction of mesons. The results for photoproduction of $\eta \pi^0 p$ and $K^0 \pi^0 \Sigma^+$, together with related reactions will be shown, having with common denominator the excitation of the $\Delta(1700)$ resonance which is one of those dynamically generated in the chiral unitary approach. Then I will show results obtained for the $e^+ e^- \to \phi f_0(980)$ reaction which reproduce the bulk of the data except for a pronounced peak, giving support to a new mesonic resonance, X(2175). Results will also be shown for the electromagnetic form factors of the $N^*(1535)$ resonance, also dynamically generated in this approach. Finally, I will show some results on the photoproduction of the $\omega$ in nuclei, showing that present experimental results claiming a shift of the $\omega$ mass in the medium are tied to a particular choice of background and are not conclusive. One the other hand, the same experimental results show unambiguously a huge increase of the $\omega$ width in the nuclear medium.Comment: Lecture at the "International School of Nuclear Physics", 29th Course Quarks in Hadrons and Nuclei, Erice, Italy, September 2007. Note added in Proofs concerning the mixed events technique and other comments on omega productio

Preventing and addressing the stress reactions of health care workers caring for patients with COVID-19: Development of a digital platform (Be + against COVID)

Background: COVID-19 became a major public health concern in March 2020. Due to the high rate of hospitalizations for COVID-19 in a short time, health care workers and other involved staff are subjected to a large workload and high emotional distress. Objective: The objective of this study is to develop a digital tool to provide support resources that might prevent and consider acute stress reactions in health care workers and other support staff due to the COVID-19 pandemic. Methods: The contents of the digital platform were created through an evidence-based review and consensus conference. The website was built using the Google Blogger tool. The Android version of the app was developed in the Java and XML languages using Android Studio version 3.6, and the iOS version was developed in the Swift language using Xcode version 11.5. The app was evaluated externally by the Andalusian Agency for Healthcare Quality. Results: We detected the needs and pressing situations of frontline health care workers, and then, we proposed a serial of recommendations and support resources to address them. These resources were redesigned using the feedback received. A website in three different languages (Spanish, English, and Portuguese) and a mobile app were developed with these contents, and the AppSaludable Quality Seal was granted to the app. A specific self-report scale to measure acute stress and additional tools were included to support the health care workforce. This instrument has been used in several Latin American countries and has been adapted considering cultural differences. The resources section of the website was the most visited with 18, 516 out of 68, 913 (26.9%) visits, and the “Self-Report Acute Stress Scale” was the most visited resource with 6468 out of 18, 516 (34.9%) visits. Conclusions: The Be + against COVID platform (website and app) was developed and launched to offer a pool of recommendations and support resources, which were specifically designed to protect the psychological well-being and the work morale of health care workers. This is an original initiative different from the usual psychological assistance hotlines