Aviation Fuel Hedging and Firm Value Analysis using Dynamic Panel Data Methodology: Evidence from the U.S. Major Passenger Airlines

Purpose: Investigation of the relation between firms' values and aviation fuel hedging activities via a dynamic panel data methodology for the major U.S. passenger airlines during the period 2002-2011. Design/methodology/approach: We use data from nine U.S. major passenger airlines representing 77.2 per cent of the U.S. domestic airline industry, in terms of available seat miles. The data is taken from the Securities and Exchange Commission (SEC) 10-K filings, the Bloomberg database and the Bureau of Transportation Statistics. In accordance with the dynamic panel data methodology, we use cross-sectional dependence tests, first generation panel unit root tests, the Durbin-Hausman panel co-integration test, and the panel fully modified ordinary least square estimator, respectively. Findings: The Durbin-Hausman panel co-integration (DHp) test reveals a statistically significant long run relationship between firms' values and aviation fuel hedging activities for the U.S. major passenger airlines. Moreover, the results of the fully modified least square estimation suggest that aviation fuel hedging has positive impact on those firms' values. Additionally, we discuss the U.S. major passenger airlines loss of ten to fifteen per cent of their value in the global financial cris is. Another important finding is that merger agreements results in an almost 10 per cent increase in those firms' values. Research limitations/implications: Clear hedging information was manually searched for in the airlines' annual audited reports. This process was both time consuming, and labour intensive. Originality/value: This is the first study that focuses exclusively on the major U.S. passenger airlines, for the effects of hedging strategies on firm value. Furthermore, we use the DHp test which allows for a co-integration relationship in the case of integrated of different order series

EFFECTS OF REHABILITATION SERVICES ON ANXIETY, DEPRESSION, CARE-GIVING BURDEN AND PERCEIVED SOCIAL SUPPORT OF STROKE CAREGIVERS

Background: Few data are available on the specific care giving-related problems of stroke patient’s caregivers and factors that influence the burden of these caregivers. Aim: To study the influences of the active rehabilitation process on anxiety, depression, care burden and perceived social support level of stroke patients caregivers. Design: A prospective clinical trial. Setting: Patients and caregivers entering a rehabilitation program at a university hospital in Turkey. Populations: Ninety patients with a first episode of stroke and 90 caregivers responsible for their care were recruited for our study. Methods: Patients and caregivers were assessed before and after the active rehabilitation process. The functional disability level of the patients was assessed by Functional Independence Measure (FIM). The Beck Anxiety Scale (BAS) and the Beck Depression Scale (BDS) were used for anxiety and depression assessment, the Zarit Care Burden Scale (ZCBS) for care burden assessment and the Multi-Dimensional Scale of Perceived Social Support (MDSPSS) for perceived social support assessment. Results: A statistically significant rise is observed in the special person sub-assessment of MDSPSS in both female and male caregivers. Also, a significant decrease in care burden, anxiety and depression levels of caregivers was noted after the rehabilitation program (p < 0.05). Conclusion: Caregivers accept the rehabilitation period as important social support in addition to the support provided by family and friends. Also, our positive results were associated with an improvement in the patients’ functional level and an increase in the acquisition of knowledge and skill required of caregivers in order to provide care during rehabilitation. Clinical Rehabilitation Impact: The rehabilitation team should be aware of the fact that the perceived care burden may be greater due to the lack of knowledge concerning available resources and due to the inability to cope with stress effectively

Case Report External Hemorrhage from a Portacaval Anastomosis in a Patient with Liver Cirrhosis

Variceal bleeding is the major complication of portal hypertension in patients with liver cirrhosis. Hemorrhage mainly occurs in gastrointestinal lumen. Extraluminal hemorrhages are quite rare, such as intraperitoneal hemorrhages. We aimed to present a variceal bleeding case from the anastomosis on the anterior abdominal wall, as an extraordinary bleeding location, in a patient with portal hypertension in whom there were no esophageal and gastric varices

Modeling and Controller Design of a VTOL UAV

A tilt rotor VTOL UAV in tri-copter configuration is developed. The vehicle is modeled using the blade element formulation for the propulsion system, and the aerodynamic properties are obtained from a 3D panel code. Linear quadratic regulators and linear quadratic tracking controllers are designed for the attitude control of the aircraft in vertical takeoff and hover flight conditions. The vehicle is built and hover flight tests are carried out. The results demonstrate the success of the modeling carried out and the controller designed

External Hemorrhage from a Portacaval Anastomosis in a Patient with Liver Cirrhosis

Variceal bleeding is the major complication of portal hypertension in patients with liver cirrhosis. Hemorrhage mainly occurs in gastrointestinal lumen. Extraluminal hemorrhages are quite rare, such as intraperitoneal hemorrhages. We aimed to present a variceal bleeding case from the anastomosis on the anterior abdominal wall, as an extraordinary bleeding location, in a patient with portal hypertension in whom there were no esophageal and gastric varices

Changes in serum obestatin, preptin and ghrelins in patients with Gestational Diabetes Mellitus

Objectives: The present study aims to establish the levels of acylated ghrelin, desacylated ghrelin, obestatin and preptin, during pregnancy and the postpartum period in pregnant women with Gestational Diabetes Mellitus (GDM) and healthy pregnancy women

Determinants of mortality in a large group of hemodialysis patients hospitalized for COVID-19

Background: Maintenance hemodialysis (MHD) patients are at increased risk for coronavirus disease 2019 (COVID-19). The aim of this study was to describe clinical, laboratory, and radiologic characteristics and determinants of mortality in a large group of MHD patients hospitalized for COVID-19

The Turkish experience of COVID-19 infection in people with NMOSD and MOGAD: A milder course?

Background: COVID-19 is a multisystemic infection with variables consequences depending on individual and comorbid conditions. The course and outcomes of COVID-19 during neuromyelitis optica spectrum disorders (NMOSD) and myelin oligodendrocyte glycoprotein antibody-associated disorders (MOGAD) are not clearly known

Evaluation of Outcomes of Peritoneal Dialysis Patients in the Post-COVID-19 Period: A National Multicenter Case-Control Study from Turkey

© 2022 S. Karger AG, Basel. Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher.Introduction: There are not enough data on the post-CO-VID-19 period for peritoneal dialysis (PD) patients affected from COVID-19. We aimed to compare the clinical and laboratory data of PD patients after COVID-19 with a control PD group. Methods: This study, supported by the Turkish Society of Nephrology, is a national, multicenter retrospective case-control study involving adult PD patients with confirmed COVID-19, using data collected from April 21, 2021, to June 11, 2021. A control PD group was also formed from each PD unit, from patients with similar characteristics but without COVID-19. Patients in the active period of COVID-19 were not included. Data at the end of the first month and within the first 90 days, as well as other outcomes, including mortality, were investigated. Results: A total of 223 patients (COVID-19 group: 113, control group: 110) from 27 centers were included. The duration of PD in both groups was similar (median [IQR]: 3.0 [1.88-6.0] years and 3.0 [2.0-5.6]), but the patient age in the COVID-19 group was lower than that in the control group (50 [IQR: 40-57] years and 56 [IQR: 46-64] years, p < 0.001). PD characteristics and baseline laboratory data were similar in both groups, except serum albumin and hemoglobin levels on day 28, which were significantly lower in the COVID-19 group. In the COVID-19 group, respiratory symptoms, rehospitalization, lower respiratory tract infection, change in PD modality, UF failure, and hypervolemia were significantly higher on the 28th day. There was no significant difference in laboratory parameters at day 90. Only 1 (0.9%) patient in the COVID-19 group died within 90 days. There was no death in the control group. Respiratory symptoms, malnutrition, and hypervolemia were significantly higher at day 90 in the COVID-19 group. Conclusion: Mortality in the first 90 days after COVID-19 in PD patients with COVID-19 was not different from the control PD group. However, some patients continued to experience significant problems, especially respiratory system symptoms, malnutrition, and hypervolemia