Computing Performance Measures in a Multi-Class Multi-Resource Processor-Shared Loss System

This paper develops methods to compute performance measures in a specific type of loss system with multiple classes of customers sharing the same processor. Such systems arise in the modeling of a call center, where the performance measures of interest are blocking the probability of a call and the reneging probability of customers that are put on hold. Expressions for these performance measures have been derived in previous work by the authors. Given the difficulty of computing these performance measures for realistic systems, this paper proposes two different approaches to simplify this computation. The first method introduces the idea of multi-dimensional convolutions, and uses this approach to compute exact blocking and reneging probabilities. The second method establishes an adaptation of the Monte Carlo summation technique in order to obtain good estimates of blocking and reneging probabilities in large systems along with their associated confidence intervals.Queuing; loss system; processor sharing; computational analysis; approximation

To Sell or Not To Sell: Determining the Tradeoffs between Service and Sales in Retail Banking Phone Centers

Throughout the financial services industry, the call center is being recognized as a critical delivery channel, helping firms to keep existing customers, expand their business, and control costs. For banks, call centers provide a cost effective means of servicing in customer requests, and are essential in retaining customers. The traditional role of the call center as a question and answer base for the customer is still a strong motivator for their existence, There is, however, a growing tendency to blend sales related activities with traditional transaction based activities at a financial service firm's phone center. Institutions view the opportunity to sell additional products as the key to a successful phone center operation. While service-oriented businesses in other sectors of the economy are experiencing a similar proliferation in call centers, the dichotomy of a service center and a sales center is much more apparent in banking. Other sectors do not fully blend service and sales in the call center operation as fully as is the desire of financial services firms. The move to sales elsewhere in the financial services industry has been ongoing for some time. The last decade has seen a growing number of banks implementing cross-sell programs across their branch networks in an effort to become higher profit, sales-driven organizations that leverage the delivery system expense structure. Today, these sales efforts in the branches are being extended to alternative delivery channels, a major one of which is the phone center. Lack of management focus, poor hiring practices, lack of training, ineffective organization for marketing, poor service, and not knowing customers or products are only a selection of some of the barriers between resources and sales in banking that have been documented. This paper identifies some of these roadblocks in the context of retail banking phone centers. The authors show that the nature of phone center operations makes them extremely susceptible to the increasing and changing resource needs of a sales organization. The authors provide a snapshot of retail banking phone centers, a review of related literature, and then present an analytical approach to characterize the tradeoffs between service and sales in phone centers. The situation at a specific phone center is described and analyzed. The authors demonstrate that cross-selling costs. In addition to its visible costs, such as training and technology, cross-selling is shown to have detrimental effects on customer service because of the additional burdens and operational load it creates on the system. With a move to more selling, capacity needs sharply increase in terms of customer service representatives and information processing resources. These capacity implications can be easily overlooked, since they are less visible than what one would expects to encounter. The authors show how restaffing can overcome some of the congestion related problems induced by additional sales activity. The authors use a performance model described in the paper in conjunction with an optimization model to determine economically optimal staffing levels for call centers. However, they note that staffing is not the only factor to be considered. Design of customer request processes and human resource practices that support the design are equally important in determining the success of a cross-sell program. The authors intend a second phase of this study a detailed filed study of call center operations across the entire financial services industry.

How macroeconomic conditions affect systemic risk in the short and long-run?

This study quantifies the effects of macroeconomic variables on various market-based systemic-risk measures in 24 European banks over the 2008-2019 period. In a first step, I measure daily systemic risk for banks based on ∆CoVaR, MES, and SRISK frameworks, and examine the contributions of individual banks to aggregate systemic risk during specific stress events. Systemic risk in European banks has risen in the wake of the global financial crisis and the Brexit referendum result. In a second step, I investigate how macroeconomic conditions affect systemic risk in the short and long-run. I find that three systemic risk measures have a long-run stable relationship with EU industrial production, EU inflation, Euribor, and US equity market volatility, but some variables have opposite effects in the short and long-run

Primjena autologne fibrinske membrane obogaćene trombocitima (PRF) u liječenju dubokih čireva rožnice u pasa

The aim of this study was to evaluate the clinical efficacy of a platelet-rich fibrin (PRF) membrane, which is considered to be a new alternative surgical method in the treatment of vision-threatening corneal ulcers in dogs. Fourteen dogs (17 eyes) of various breeds and ages with deep corneal ulcers were treated surgically with a PRF membrane transplantation. The corneal ulcer of all the patients was closed with an autologous platelet-rich fibrin membrane. In the first 10 days after the operation, it was observed that the fibrin membrane partially melted, and corneal epithelialization and granulation tissue occurred in and around the ulcer area due to the graft material. Pain was significantly relieved, and conjunctival inflammation was noticeably improved. From the 20th day after the surgery, the granulation tissue was gradually cleaned. It was determined that all the eyes had vision. The most common complications after surgery were corneal pigmentation and fibrosis of varying severity. The use of autologous fibrin membranes is a safe and effective surgical alternative for the closure and healing of corneal ulcers. Our findings show that the autologous platelet-rich fibrin membrane is useful and effective in treating canine corneal deep ulcers.Čirevi rožnice mogu oštetiti vid u pasa. Cilj je ovog istraživanja bio procijeniti kliničku učinkovitost fibrinske membrane obogaćene trombocitima (PRF), kao nove alternative kirurških metoda u liječenju čireva rožnice. Četrnaest pasa (17 očiju) različitih pasmina i dobi, s dubokim čirevima rožnice liječeno je kirurški transplantacijom. Čir na rožnici u svih je pacijenata bio zatvoren autolognom fibrinskom membranom obogaćenom trombocitima. Prvih 10 dana nakon kirurškog zahvata uočeno je da se fibrinska membrana parcijalno talila, dok se na čiru i oko njega pojavilo epitelizacijsko i granulacijsko tkivo zbog graft materijala. Bol je znatno ublažena, a upala konjunktive osjetno smanjena. Od 20. dana nakon kirurškog zahvata granulacijsko je tkivo postupno očišćeno. Pokazalo se da je svim psima vraćen vid. Najčešće su komplikacije nakon kirurškog zahvata bile pigmentacija rožnice i fibroza različita stupnja. Rezultati istraživanja pokazuju da je autologna fibrinska membrana obogaćena trombocitima sigurna, korisna i učinkovita kirurška alternativa u liječenju dubokih čireva rožnice u pasa

Early postpartum lactation effects of cesarean and vaginal birth

Objectives: Breastfeeding has positive effects for both, the mother and the infant. The purpose of the study was to ex­amine how cesarean delivery and vaginal delivery influenced subsequent breastfeeding. The study was conducted at the Kırıkkale University Medical School. Material and methods: Breastfeeding outcomes after an elective cesarean delivery and after a planned vaginal delivery were compared. The study included 169 consenting mothers who gave birth to healthy infants (86 cesarean deliveries and 83 vaginal deliveries) between March and September 2001. All cesarean deliveries were performed under regional anesthesia. Results: Elective cesarean delivery was performed at a significantly earlier gestational age as compared to vaginal delivery (p = 0.001). Maternal age in the planned vaginal delivery group was significantly lower (p = 0.003). As for the change in prolactin levels, the results were similar but not statistically significant (p = 0.21). The frequency of breastfeeding per day did not differ significantly between the groups (p = 0.20). However, women after cesarean delivery tended to breastfeed more often than after vaginal delivery (p = 0.003). Mean number of points recorded at the first breastfeeding session, according to the LATCH charting system, was lower in the group after cesarean delivery as compared to vaginal labor. The difference between the average point scores of vaginal delivery and cesarean delivery mothers was found to be meaningful in favor of the women after vaginal delivery (p = 0.05). Conclusions: Elective cesarean section has negative effects on breastfeeding. Our results indicate that cesarean section constitutes a risk factor for delayed lactogenesis

A retrospective evaluation of critically ill patients infected with H1N1 influenza A virus in Bursa, Turkey, during the 2009–2010 pandemic

Background: H1N1 influenza A virus infections were first reported in April 2009 and spread rapidly, resulting in mortality worldwide. The aim of this study was to evaluate patients with H1N1 infection treated in the intensive care unit (ICU) in Bursa, Turkey.Methods: Demographic characteristics, clinical features, and outcome relating to H1N1 infection were retrospectively analysed in patients treated in the ICU.Results: Twenty-three cases of H1N1 infection were treated in the ICU. The mean age of patients was 37 years range: (17– 82). Fifteen patients were female (65.2%). The mean Acute Physiology and Chronic Health Evaluation (APACHE) II score was 19 range: (5–39). The most common symptoms were dyspnea (73.9%), fever (69.6%), and cough (60.9%). Mechanical ventilation was required for all patients. Oseltamivir and antibiotics were administered to all patients. Six (26.1%) patients died. APACHE II scores were higher in the deceased 28.5 range: [16–39] vs. 14 range: [5–28] in survivors; p = 0.013).Conclusion: When compared to the literature, the demographic, epidemiological, and clinical characteristics were similar in the cases we encountered. The mortality rate was high despite the use of appropriate treatment. We believe that the high mortality is related to higher APACHE II scores. The H1N1 virus should be considered in community acquired pneumonia, especially in younger patients presenting with severe pneumonia.Key words: pandemic influenza, H1N1 infection, critically ill patient, intensive care uni

European sovereign bond and stock market Granger causality dynamic

We investigate the lead-lag relationship between weekly sovereign bond yield changes and stock market returns for eight European countries, and how it changed during the period 2008-2018. We use a Markov-Switching Granger Causality method that determines reversals of causality endogenously. In all countries, there were often changes in the direction of the Granger causality between the two markets that coincided with global and idiosyncratic economic events. Stock returns led changes of sovereign bond yields in all countries, particularly during the financial and the Euro Area crisis. Changes of sovereign bond yields occasionally led stock returns in France, Spain and Portugal

Subglacial Lake Vostok (Antarctica) Accretion Ice Contains a Diverse Set of Sequences from Aquatic, Marine and Sediment-Inhabiting Bacteria and Eukarya

Lake Vostok, the 7th largest (by volume) and 4th deepest lake on Earth, is covered by more than 3,700 m of ice, making it the largest subglacial lake known. The combination of cold, heat (from possible hydrothermal activity), pressure (from the overriding glacier), limited nutrients and complete darkness presents extreme challenges to life. Here, we report metagenomic/metatranscriptomic sequence analyses from four accretion ice sections from the Vostok 5G ice core. Two sections accreted in the vicinity of an embayment on the southwestern end of the lake, and the other two represented part of the southern main basin. We obtained 3,507 unique gene sequences from concentrates of 500 ml of 0.22 μm-filtered accretion ice meltwater. Taxonomic classifications (to genus and/or species) were possible for 1,623 of the sequences. Species determinations in combination with mRNA gene sequence results allowed deduction of the metabolic pathways represented in the accretion ice and, by extension, in the lake. Approximately 94% of the sequences were from Bacteria and 6% were from Eukarya. Only two sequences were from Archaea. In general, the taxa were similar to organisms previously described from lakes, brackish water, marine environments, soil, glaciers, ice, lake sediments, deep-sea sediments, deep-sea thermal vents, animals and plants. Sequences from aerobic, anaerobic, psychrophilic, thermophilic, halophilic, alkaliphilic, acidophilic, desiccation-resistant, autotrophic and heterotrophic organisms were present, including a number from multicellular eukaryotes. © 2013 Shtarkman et al