Essays on Consumer Returns and Retail Operations

This dissertation offers two essays that together represent a deep investigation into consumer returns, channel integration via ship-to-store service, and omnichannel retailing practices. The results provide strong managerial insights regarding some of the widely implemented industry practices associated with consumer return abuse and omnichannel retailing. The first essay investigates return abuse with respect to both fraudulent and opportunistic consumer returns and two potential technology-enabled countermeasures to deal with them: customer profiling and product tracking. A customer profiling system identifies opportunistic customers by using their personal identification and transaction history. In contrast, a product tracking system identifies fraudulent returns by recording each transaction of a product through the use of unique identifiers. We demonstrate how these countermeasures impact a retailer's profitability, demand structure, and policy parameters with respect to price and refund. The second essay looks into channel integration via ship-to-store service and investigates the impact of this omnichannel retailing practice on sales and returns across both online and brick-and-mortar channels. The advent of omnichannel retailing technologies enable integration of both physical and electronic marketplaces that is designed to deliver a seamless shopping experience to customers. For a retailer, these capabilities require significant investment, yet hold the promise of enhancing the revenue streams from both online and brick and mortar channels. We assess this promise by using transactional data from a national retailer to analyze the impact of introducing ship-to-store capability on a retailer's performance. Contrary to expectations, our findings show that online sales decrease after ship-to-store is implemented, although store sales increase. Some customers switch from the online channel to the brick-and-mortar channel. This occurs mainly for high-value purchases. The customers who actually use the ship-to-store service are those that typically buy low-value items. Our results also show that implementing ship-to-store increases returns of online purchases to physical stores. At the same time, these types of returns generate additional selling opportunities. About 28 percent of the online purchases returned to a store are associated with a new purchase, amounting to more than $7 million in additional revenue

Usefulness of the uric acid and CHA2DS2-VASc score in prediction of left atrial thrombosis in patients with mitral stenosis and sinus rhythm

Background: The risk of thrombus formation in the left atrium is known to be very high in patients with both mitral stenosis (MS) and atrial fibrillation (AF). However, that risk should not be ignored in patients with MS in sinus rhythm (SR). The aim of this study was to determine the clinical, echocardiographic, and biochemical factors that could have a determining role in the formation of a left atrial (LA) thrombus in patients with MS in SR. Method: A total of 207 consecutive patients with MS who underwent both transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE) for diagnosis or to investigate the presence of a thrombus in the LA and appendage were enrolled in this study. Results: LA thrombus was detected in 21 of 207 patients. CHA2DS2-VASc score was not found to be a predictor of LA thrombosis in patients with MS in SR, despite the higher CHA2DS2-VASc scores observed in those patients. The mitral valve area and mitral valve gradient were not predictive of LA thrombus development; however, LA anteroposterior diameter (LAAPD) was found to be a predictor of LA thrombosis. Levels of high sensitivity-C-reactive protein and uric acid were higher in the patients with LA thrombosis, but only uric acid was found to be a predictor of LA thrombosis in multivariate analysis. Conclusions: A larger LAAPD and an elevated serum uric acid level were found to be independent predictors of LA thrombosis in patients with MS in SR.

Integrated Scheduling and Tool Management in Flexible Manufacturing Systems

A multistage algorithm is proposed that will solve the scheduling problem in a flexible manufacturing system by..

Cavitary lung disease in renal transplant recipients: A single center experience

Background: Cavitary lung disease (CLD) in renal transplant recipients is an infrequent complication causing high morbidity and mortality. We aimed to examine incidence, demographics and treatment properties of cavitary lung lesions in our renal transplant patient population. Methods: We retrospectively examined renal transplant recipients, who were operated between January 2002-October 2013 and observed at Renal Transplantation Unit of Ankara University Faculty of Medicine. Demographic features, treatment and outcome of cavitary CLD were investigated. Results: A total of 343 kidney recipients were studied, 7 (2.0%) of whom developed CLD. Median time to develop CLD was 15 months (min:1, max:115) after transplantation. 3 (42.8%) patients had experienced acute rejection and treated with anti-thymocyte globulin within 6 months prior to disease development date. No graft lost, but 2 (28.5%) patient lost was seen because of CLD. Conclusions: Although developments in immunsuppression and antibiotic treatment in recent decades, cavitary lung disease is an important morbidity and mortality reason in renal transplant recipients

NT-proBNP level in stage 3-4 chronic kidney disease and mortality in long-term follow-up: HAPPY study subgroup analysis

Objective: This was an investigation of the relationship between the N-terminal pro-brain natriuretic peptide (NT-proBNP) level and mortality in patients with stage 3-4 chronic kidney disease (CKD)

Non-Diabetic Kidney Disease in Type 2 Diabetic Patients: Prevalence, Clinical Predictors and Outcomes

Background/Aims: Diabetic kidney disease (DKD) is one of the most frequent microvascular complications of diabetes and is the leading cause of end-stage kidney disease worldwide. In patients with diabetes, non-diabetic kidney disease (NDKD) can also occur. NDKD can be either alone or superimposed with the DKD. In this study, we aimed to investigate the utility of kidney biopsy in patients with type 2 diabetes mellitus (T2DM) and the predictability of diagnosing DKD versus NDKD from clinical and laboratory data. We also evaluated the prevalence and etiology of NDKD in patients with T2DM. Methods: We retrospectively reviewed type 2 diabetic patients who had kidney biopsy in the last 10 years for diagnosing possible NDKD in our center. In all patients kidney biopsies were performed because of atypical clinical features and biopsy samples were examined by light and immunofluorescence microscopy. Clinical parameters, laboratory workup and office blood pressures were recorded for each patient at the time of biopsy. Results: Eight patients were excluded due to missing data. A total of 48 patients (female/male: 26/22 and mean age: 59±8 years) were included in the study. According to the biopsy findings, 24 (50%) patients had NDKD alone, 20 (41.7%) had DKD alone and 4 (8.3%) had coexisting DKD and NDKD. The most common NDKD diagnoses were membranous nephropathy (29.2%), tubulointerstitial nephritis (20.8%) and IgA nephropathy (12.5%). There were no significant differences in three groups with respect to the duration of diabetes, proteinuria, hematuria and glycated hemoglobin A1c levels. Diabetic retinopathy (DR) was the most significant finding, which was associated with DKD. Positive and negative predictive values of DR for DKD were 88 and 81%, respectively. Conclusion: This study demonstrated a high prevalence of NDKD in patients with T2DM. The absence of DR strongly predicted NDKD. Clinical decision alone can lead to wrong diagnosis and delay in appropriate therapy. Clinicians should consider the kidney biopsy more liberally when there is uncertainty on the exact etiology of the kidney disease. However, prospective multicenter studies are needed to clarify the prognosis and outcomes of patients with diabetics