On condition numbers of polynomial eigenvalue problems with nonsingular leading coefficients

In this paper, we investigate condition numbers of eigenvalue problems of matrix polynomials with nonsingular leading coefficients, generalizing classical results of matrix perturbation theory. We provide a relation between the condition numbers of eigenvalues and the pseudospectral growth rate. We obtain that if a simple eigenvalue of a matrix polynomial is ill-conditioned in some respects, then it is close to be multiple, and we construct an upper bound for this distance (measured in the euclidean norm). We also derive a new expression for the condition number of a simple eigenvalue, which does not involve eigenvectors. Moreover, an Elsner-like perturbation bound for matrix polynomials is presented.Comment: 4 figure

Testing technical anomalies in Athens stock exchange (ASE)

The purpose of this paper is to investigate the existence of historical Market anomalies in the Athens Stock Market (ASE). The market anomalies that are going to be explored are technical ones concerning the trading rules of the various types of moving averages. The above anomalies were observed in most developed and developing markets. This study will investigate these effects for the most important index of the Athens market, the Athens General Index. The data used are for the period from 1/1/1990 to 31/12/2004. Overall, our results confirm the existence of technical anomalies in ASE and provide strong support for profitability of those technical trading rules.peer-reviewe

Investigation of the Total Phenolic Content and Antioxidant Capacity of Three Sweet Pepper Cultivars (Capsicum annuum L.) at Different Development and Maturation Stages

The aim of the current research was to investigate and compare the total phenolic content and antioxidant capacity of sweet pepper cultivars at different development and maturation stages, in order to optimize the beneficial effects. For that purpose, three important sweet pepper cultivars, namely Dolmy-F1, Yahoo-F1 and Florinis-NS-700, were cultivated in a greenhouse. Their total phenolic content, ascorbic acid content and antioxidant properties were assessed at different development and maturation stages. In the aforementioned cultivars, the total phenolic content ranged from 345.2 to 602.1, 404.9 to 794.5, and 795.7 to 2220.3 μg GAE g−1 FW respectively. The ascorbic acid content ranged from 236 to 957, 258 to 1157, and 410 to 1550 μg AA g−1 FW respectively. The highest antioxidant activity was noted at the red maturity stage. Particularly the cultivar Florinis NS 700 was found to possess higher total phenolic, flavonoid phenol, non-flavonoid phenol, ascorbic acid contents, and greater antioxidant capacity, compared to the other cultivars. The results of our study recommend the consumption of the sweet peppers at red maturity stage, for achieving the maximum health-beneficial effects

Altered Brain Functional Connectivity in Small-Cell Lung Cancer Patients after Chemotherapy Treatment: A Resting-State fMRI Study

Previous studies in small-cell lung cancer (SCLC) patients have mainly focused on exploring neurocognitive deficits associated with prophylactic cranial irradiation (PCI). Little is known about functional brain alterations that might occur due to chemotherapy treatment in this population before PCI is administered. For this reason, we used resting-state functional Magnetic Resonance Imaging (fMRI) to examine potential functional connectivity disruptions in brain networks, including the Default Mode Network (DMN), the Sensorimotor Network, and the Task-Positive Network (TPN). Nineteen SCLC patients after platinum-based chemotherapy treatment and thirteen controls were recruited in the current study. ROI-to-ROI and Seed-to-Voxel analyses were carried out and revealed functional connectivity deficits in patients within all the networks investigated demonstrating the possible negative effect of chemotherapy in cognitive functions in SCLC populations

Debatable results of surgery for lung cancer in a patient with long existing pulmonary metastases from differentiated thyroid carcinoma

Introduction: The appropriate following treatment in a patient with a new presented non-small cell lung cancer (NSCLC) and history of chronic lung metastases of thyroid origin has never been reported. In such cases, the presence of long­standing thyroid metastatic disease with proven “limited malignant potential” could be considered as a minor treatment problem justifying one’s the decision to focus on the primary lung carcinoma as the only serious threat for the patient’s life.Case report: We report the surgical treatment of a new presented NSCLC in a patient with chronic lung metastases of thyroid origin and we present all the diagnostic, staging and treatment problems.Conclusion: The therapeutic results of our surgical approach were not encouraging. This could be owed to our staging prob­lems of NSCLC and the well documented limited immunological response of such patients with multiple neoplasms

Bilateral rectus femoris intramuscular haematoma following simultaneous quadriceps strain in an athlete: a case report

<p>Abstract</p> <p>Introduction</p> <p>Bilateral rectus femoris haematoma following a simultaneous strain of the quadriceps muscles is a very rare condition.</p> <p>Case presentation</p> <p>We report the case of a 21-year-old Greek Caucasian female rowing athlete who was injured on both thighs. She complained of pain and inability to walk. Physical examination revealed tenderness over the thighs and restriction of knee movement. The result of a roentgenogram was normal, and there was no evidence of fracture or patella displacement. Magnetic resonance imaging revealed haematoma formation in both the rectus femoris muscles. The diameters of the left and right haematomas within the muscles were 6 cm and 5 cm, respectively. Therapeutic approaches included compression bandages, ice application, rest, elevation, and administration of muscle relaxant drugs. Active stretching and isometric exercises were performed after three days. The patient was able to walk using crutches two days after the initiation of treatment. On the seventh day, she had regained her full ability to walk without crutches. Non-steroidal anti-inflammatory drugs were administered on the fifth day and continued for one week. Six weeks later, she had pain-free function and the result of magnetic resonance imaging was normal. She was able to resume her training programme and two weeks later, she returned to her previous sport activities and competitions.</p> <p>Conclusion</p> <p>There are references in the literature regarding the occurrence of unilateral quadriceps haematomas following strain and bilateral quadriceps tendon rupture in athletes. Simultaneous bilateral rectus femoris haematomas after a muscle strain is a rare condition. It must be diagnosed early. The three phases of treatment are rest, knee mobilization, and restoration of quadriceps function.</p