Determination of the bundle price for digital information goods

The fast emergence of Internet as a media to distribute digital information goods created many new opportunities for the packaging and pricing of these goods. The pricing of information goods introduces a challenge since the cost structure of information goods differs from that of conventional physical goods in that they can be costly to introduce but are relatively cheap to reproduce. The bundling strategy for digital information goods helps producers to extract more value from customers and can result in cost savings due to the presence of economies of scale. This study aims to determine the optimum price a producer of digital information goods has to charge for a bundle in order to maximize his gross margin. The bundle pricing model is constructed for both uniform and exponential distributions of the fraction of information goods in the bundle that has positive value for the customers

Exoresection via partial lamellar sclerouvectomy approach for uveal tumors: A successful performance by a novice surgeon

Rengin Aslıhan Kurt, Kaan GündüzDepartment of Ophthalmology, Ankara University Faculty of Medicine, Ankara, TurkeyPurpose: To evaluate the results and complications of exoresection via a partial lamellar sclerouvectomy (PLSU) procedure for uveal tumors performed by a novice surgeon without help from an experienced surgeon.Methods: Medical records of 22 patients who underwent exoresection for uveal tumors between February 1999 and January 2009 were evaluated retrospectively. Exoresection was considered for tumors with their epicenter in the iris or in the ciliary body.Results: Twenty-two patients with a mean age of 45.9 years (range: 19–72 years) were included in this study. The histopathologic diagnosis was uveal malignant melanoma in 16 patients, iridociliary nevus in 2 patients, iris nevus in 2 patients, and iridociliary melanocytoma in 2 patients. Postoperative complications included cataract in 11 patients (50%), scleral thinning in 4 patients (18%), vitreous hemorrhage in 2 patients (9%), hyphema in 2 patients (9%), secondary glaucoma in 2 patients (9%), iridodialysis in 1 patient (4.5%), bullous keratopathy in 1 patient (4.5%), and posterior synechiae in 1 patient (4.5%). At a mean follow-up of 40.1 months (range: 1–98 months), there were no recurrences or metastatic events.Conclusions: Exoresection seems to be an effective treatment option in selected cases of iridociliary and ciliary body tumors. Novice surgeons with limited training in PLSU should not discourage themselves from doing this type of surgery. Several postoperative complications inevitably occur and require frequent patient monitoring.Keywords: uveal melanoma, uveal nevus, iris, ciliary body, choroid, iris nevus, iris melanoma, ciliary nevus, ciliary melanoma, choroidal melanoma, ciliochoroidal melanoma, iridociliochoroidal melanoma, partial lamellar sclerouvectomy, exoresectionErratum for this paper has been publishe

Lacrimal gland tumors in Turkey: types, frequency, and outcomes.

AIM: To evaluate the clinical, radiological, and treatment features of lacrimal gland tumors. METHODS: Retrospective review of 99 eyes of 92 patients with lacrimal gland tumors diagnosed and managed in a single institution between January 1999 and March 2017. Clinical and radiological features, histopathology, treatment methods, and prognosis were evaluated. RESULTS: The mean patient age was 40.3 (range: 7-80)y. The diagnosis was made histopathologically in 91 (91.9%) tumors and on a clinical and radiological basis in 8 (8.1%) tumors. Final diagnoses included idiopathic orbital inflammation (pseudotumor) in 46 (46.5%) lesions, pleomorphic adenoma in 14 (14.1%), adenoid cystic carcinoma in 12 (12.1%), granulomatous inflammation in 10 (10.1%), lymphoma in 5 (5.0%), benign reactive lymphoid hyperplasia in 3 (3.0%), dacryops in 3 (3.0%), carcinoma ex pleomorphic adenoma in 2 (2.0%), adenocarcinoma in 1 (1.0%), dermoid cyst in 1 (1.0%), cavernous hemangioma in 1 (1.0%), and leukemic infiltration in 1 (1.0%). Non-epithelial tumors comprised 64.6% ( CONCLUSION: Overall, 65% of lacrimal gland tumors were of non-epithelial origin and 32% of epithelial origin. By histopathology and clinical evaluation, 79% of lacrimal gland tumors were benign. The most common lacrimal gland tumors include idiopathic orbital inflammation (46.5%), epithelial (32.3%), and lymphoproliferative (8.1%) lesions

Benign cementoblastoma : a case report

In the past the benign cementoblastoma was recognized in the World Health Organization?s classification of odontogenic tumours as one of the cementoma neoplasias. Recently the benign cementoblastoma is included into ?Mesenchyme and/or odontogenic ectomesenchyme, with or without odontogenic epithelium? odontogenic tumours. Benign cementoblastoma has characteristic radiologic and microscopic features and it appears to be fused to the tooth roots. Symptoms may be totally absent, and when they do occur, pain and swelling are frequent findings. The final diagnosis is usually made histopathologically, but the clinical diagnosis is comparatively easy if it is examined radiographically. The tumour has unlimited growth potential. Most frequently tends to be associated with an erupted permanent tooth, most often the first molar: rarely has an association with an impacted or partial impacted tooth been reported. This case represents a case of benign cementoblastoma associated with a partially impacted mandibular third molar

Prevalence and distribution of odontogenic and nonodontogenic cysts in a Turkish population

Objective: To determine the relative frequency and distribution of odontogenic and nonodontogenic cysts in a large Turkish population. Study Design A retrospective survey of jaw cysts was undertaken at the Oral Diagnosis and Radiology and Oral and Maxillofacial Surgery Department, Ondokuz Mayis University Dental School, Samsun, Turkey. Data were retrieved from clinical files, imaging, and histopathology reports from 2000 to 2008: a total of 12,350 patients were included. In each case, we analyzed age, gender, type and number of cysts, and cyst location. Imaging patterns and pathologies associated with cystic lesions were also determined. Results: The prevalence of odontogenic and nonodontogenic cysts was 3.51%; males were affected more frequently than females. There were 452 odontogenic cysts (98.5%) and seven nonodontogenic cysts (1.5%). The most frequent odontogenic cyst was radicular (54.7%), followed by dentigerous (26.6%), residual (13.7%), odontogenic keratocyst (3.3%), and lateral periodontal cyst (0.2%). Nasopalatine duct cyst (1.5%) was the only nonodontogenic cyst. By age, cysts peaked in the third decade (24.2%). Concerning location, no statistically significant difference was found between the maxilla and mandible (p>0.05). The most frequent radiological feature of these lesions was unilocular cyst (93.7%). Pathologies associated with cystic lesions occurred in 14.7%. Conclusion: The prevalence of both odontogenic and nonodontogenic cysts were lower than that reported in many other studies. In our study population, cysts were mainly inflammatory in origin. © Medicina Oral S. L

A retrospective study of the prevalence and characteristics of dens invaginatus in a sample of the Turkish population

Objective: The purpose of this study was to assess the prevalence of dens invaginatus and to classify the types of dens invaginatus in a sample of the Turkish population.. Study Design: A retrospective study was performed using periapical and panoramic radiographs of 5355 patients who presented to the Department of Oral Diagnosis and Radiology at the Ondokuz May?s University Dentistry Faculty between January 2009 and December 2010. Maxillary and mandibular anterior teeth were evaluated for the presence and characteristics of dens invaginatus. Statistical evaluation of the presence of dens invaginatus related to gender was performed by the Pearson chi-squared test. Results: Dens invaginatus was observed in 116 of 4556 subjects, with a frequency of 2.5%. There was only one periapical lesion in teeth with type I dens invaginatus, but 8.1% of patients with type II and 87.5% of patients with type III dens invaginatus had apical periodontitis at the time of referral. There were 116 (72%) females and 32 (27%) males with dens invaginatus. Conclusion: This data represents the only study carried out in a large population in Turkey, and no dens invaginatus was found in mandibular teeth. The most commonly observed type of dens invaginatus was type I (69.8%)

Lamellar Keratoplasty Using Microkeratome-Assisted Anterior Lamellar Graft in the Management of Deep Limbal Dermoid: A Case Report

Limbal dermoid is a congenital benign tumor of the limbus which is often managed by surgery if necessary. In dermoid lesions involving the deep stroma, tumor excision and reconstruction of the anterior segment with amniotic membrane transplantation or keratoplasty may be required. Herein, we present a case of deep limbal dermoid treated with surgical resection and lamellar keratoplasty using microkeratome-assisted anterior lamellar graft

Regional odontodysplasia of the deciduous and permanent teeth associated with eruption disorders : a case report

Regional odontodysplasia (RO) is an unusual, non-hereditary anomaly of the dental hard tissues with characteristic clinical, radiographic and histological findings. Clinically, RO affects the primary and permanent dentition in the maxilla and mandible or both jaws. Radiographically, there is a lack of contrast between the enamel dentin, both of which are less radiopaque than unaffected counterparts. Additionally, enamel and dentin layers are thin, giving the teeth a ?ghost-like? appearance. Histologically, areas of hypocalcified enamel are visible and enamel prisms appear irregular in direction. Coronal dentin is fibrous, consisting of clefts and a reduced number of dentinal tubules; radicular dentin is generally more normal in structure and calcification. The RO etiology is uncertain; numerous factors have been suggested and considered as local trauma, irradiation, hypophosphatasia, hypocalcemia, hyperpyrexia. The treatment of RO has given rise to controversy. These cases require a continuous and multidisciplinary approach. Most clinicians advocate extracting the affected teeth as soon as possible and inserting a prosthetic replacement. Other clinicians prefer restorative procedures, if possible, to protect the affected erupted teeth. A case of RO in an 8 year-old male whose chief complaint was the absence of eruption of permanent teeth is presented. Clinical, radiographic and histological findings are described

ELEKTRONİK DENEYLERİ İÇİN SANAL LABORATUAR UYGULAMASI

Web tabanlı eşzamansız (asenkron) eğitim son zamanlarda ülkemizde ve dünyada yeni ve gelişen bir eğitim modeli olarak karşımıza çıkmaktadır. Bu çalışmada Selçuk Üniversitesi Mühendislik Mimarlık Fakültesi Bilgisayar Mühendisliği Bölümünde temel donanım derslerini web tabanlı olarak desteklemek ve deneysel uygulamaların altyapısını oluşturmak üzere bir çalışma amaçlanmıştır. Sanal laboratuar sitesi ile öğrenciler için ders materyalleri hazırlanmış, gerçekleştirilecek uygulamaların benzetimleri (simulation) yapılmış, konu testleri eklenmiş ve bir adet dönem sonu sınavı hazırlanmıştır. Öğrenciler web aracılığı ile ders materyallerine ulaşarak uygulamanın nasıl yapılacağını görmekte, benzetim yaparak kurulacak uygulamanın şemasını ve uygulama sonunda elde edeceği sonuçları görebilmekte, konu testleri alabilmekte ve dönem sonunda bir çevrimiçi sınav alabilmektedir. Temel donanım uygulamalarında öğrencilere faydalı olabilmek amacıyla hazırlanan bu çalışmanın uygulamaya girmesiyle birlikte, öğrencilerin derslere daha hazır gelmeleri, gerçekleştirdikleri deneylerin doğruluğunu görerek emin olmaları, hazırlanan testler sayesinde sınavlara daha iyi hazırlanmaları, geribildirimler sayesinde kendilerini daha iyi değerlendirebilmeleri hedeflenmektedir