Network Structure and Design in the Deregulated U.S. Airline Industry: an Argument for Re-Regulation?

This paper develops a model to explain and analyze the evolution of network structure (connectivity)and design (flight frequency, aircraft size, prices) in the post-deregulation U.S. airline industry. We show that legacy carriers choice of Hub-and-Spoke networks and the emergence of low cost carriers (LCCs) operating Point-to-Point networks were optimal choices. We demonstrate that LCCs need not necessarily charge lower prices, and their entry impacted legacy carriers’ prices in all markets, even those where there is no direct competition. We show that in response to entry, legacy carriers optimally lower flight frequency, leading to longer wait times between flights for which passengers are compensated by lower prices; conversely, if the entrant later exits, legacy carriers raise flight frequency and therefore prices, which may erroneously appear to be predatory pricing when in fact it is the consequence of optimal network redesign. Finally, we demonstrate that even though low cost carriers lower prices, total social welfare with competing network structures can also be lowered. In other words, the poor financial performance of legacy carriers is not due to their inefficiency per se but due to an efficient Hub-and-Spoke network undermined by competition from inefficient Point-to-Point networks. We argue that social welfare may have been, and still can be, higher if entry and exit in air passenger travel industry is regulated.Networks, Airlines, Regulation

Do body mass index, hormone profile and testicular volume effect sperm retrieval rates of microsurgical sperm extraction in the patients with nonobstructive azoospermia?

WOS: 000436167000005PubMed ID: 29733793Objective: We aimed to evaluate the effect of body mass index (BMI), follicle stimulating hormone (FSH), and luteinizing hormone (LH) levels and the mean testicular volume on sperm retrieval rates in microsurgical sperm extraction (microTESE) in the patients with nonobstructive azoospermia (NOA). Material and methods: The data of 282 infertile patients with NOA were analysed retrospectively. The patients with normal karyotype and no Y microdeletions were included in the study. The patients were classified according to their BMI scores and the medical history, physical examination and hormonal parameters were evaluated. The overall data were processed statistically with chi-square and logistic regression analysis and the relation between preoperative findings and sperm retrieval rates was investigated. Results: The sperm retrieval rate of 282 patients after microTESE was found as 41.1%. There was no statistically significant difference in sperm retrieval rates among the subgroups classified according to BMI. FSH and LH levels and the mean testicular volume and pathologic findings were significantly correlated with sperm retrieval rates. Conclusion: Finally significant correlation was determined between sperm retrieval rates and FSH, and LH levels and testicular volumes but no statistically significant difference was found in sperm retrieval rates among BMI groups

Prognostic value of basal neutrophil lymphocyte ratio in patients with extensive stage small cell lung cancer

Purpose: The neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR) and lymphocytopenia are markers of poor prognosis in lung cancer patients. The aim of this trial is evaluate the prognostic significance of basal NLR, PLR and lymphocytopenia in patients with extensive stage (ES) small cell lung cancer(SCLC). Materials and Methods: This study was designed as a hospital-based retrospective observational case-series study. A total of 117 patients with extensive stage small cell lung cancer have been treated at four different oncology centers in Turkey between 2011 and 2017. Laboratory results and demographic data were collected. Results: The median follow-up time was 12 months and 95 (81%) patients died. Progression-free survival (PFS) and overall survival (OS) were estimated, respectively, as 8 and 13 months. 65 (55.6 %) patients had complete response at the end of first line platin-etoposide combination treatment. The cut-off value for NLR and PLR were determined for whole group and patients were dichotomized into high (>= 3.28) and low (= 139.8) and low (< 139.8) PLR groups.. Median OS was lower in patients who had high neutrophil lymphocyte ratio (NLR) (14 versus 12 months respectively). Conclusion: This study showed that basal NLR may have prognostic biological value in patients with ES SCLC treated with cisplatin + etoposide

Real-world outcomes of pazopanib in metastatic soft tissue sarcoma: a retrospective Turkish oncology group (TOG) study

Aim: Description of patient characteristics, effectiveness and safety in Turkish patients treated with pazopanib for metastatic soft tissue sarcoma (STS). Patients and methods: This multicenter study is based on retrospective review of hospital medical records of patients (≥ 18 years) treated with pazopanib for non-adipocytic metastatic STS at 37 Oncology clinics across Turkey. Objective response rate (ORR), disease control rate (DCR), progression-free survival (PFS) and overall survival (OS) were evaluated with further analysis of data on the three most common histological subtypes (leiomyosarcoma [LMS], undifferentiated pleomorphic sarcoma [UPS], synovial sarcoma [SS]) in the cohort. Results: Data of 552 adults (57.6% women, median age: 52 years) were analyzed. DCR and ORR were 43.1% and 30.8%, respectively. Median PFS was 6.7 months and OS was 13.8 months. For LMS, UPS and SS, median PFSs were 6.1, 5.9 and 7.53 months and median OSs were 15.03, 12.87 and 12.27 months, respectively. ECOG ≥ 2 was associated with poor PFS and OS. Liver metastasis was only a factor for progression. Second-line use of pazopanib (vs. front-line) was associated with better PFS, its use beyond third line predicted worse OS. Adverse events (AE) occurred in 82.7% of patients. Most common AEs were fatigue (58.3%) and anorexia (52.3%) which were graded as ≥ 3 in 8.2% and 7.4% of patients, respectively. Conclusion: Pazopanib is effective and well-tolerated in treatment of non-adipocytic metastatic STS. Its earlier use (at second-line), good performance status may result in better outcomes. Worldwide scientific collaborations are important to gain knowledge on rarer STS subtypes by conducting studies in larger patient populations

Efficacy and Safety of Trastuzumab Emtansine in Her2 Positive Metastatic Breast Cancer: Real-World Experience

Aim The aim of this study is to evaluate the efficacy and toxicity of trastuzumab emtansine (T-DM1) in cases with metastatic breast cancer (mBC) in different lines of treatment. Method Retrospective analysis of T-DM1 results of human epidermal growth factor receptor 2 (Her2) positive 414 cases with mBC from 31 centers in Turkey. Findings Except 2, all of the cases were female with a median age of 47. T-DM1 had been used as second-line therapy in 37.7% of the cases and the median number of T-DM1 cycles was 9. Progression-free survival (PFS) and overall survival (OS) times were different according to the line of treatment. The median OS was found as 43, 41, 46, 23 and 17 months for 1st, 2nd, 3rd, 4th and 5th line, respectively (p = 0.032) while the median PFS was found as 37, 12, 8, 8 and 8 months, respectively (p = 0.0001). Treatment was well tolerated by the patients. The most common grade 3-4 adverse effects were thrombocytopenia (2.7%) and increased serum gamma-glutamyl transferase (2%). Discussion The best of our knowledge this is the largest real-life experience about the safety and efficacy of T-DM1 use in cases with mBC after progression of Her2 targeted treatment. This study suggests and supports that T-DM1 is more effective in earlier lines of treatment and is a reliable option for mBC