Telecommunication Network Competition: An Equilibrium Analysis

The paper analyzes calling party pays access pricing policies in a General Equilibrium two ways access charge model with consumers that choose between different telecommunication providers, and benefit from making calls to other consumers and from the calls that they receive. We obtain that agents' network decision may leads to an inefficient industry structure where from a social point of view the network competitively chosen by the agents is an inferior one. Under ad-hoc parameter values we obtain that if each telecommunication company faces a fixed cost, becomes of higher efficient to finance this cost through a fixed charge on the telephone line, an access charge, and setting telecommunication companies interconnection charges equal to each company interconnection marginal cost, where policies that finance fixed or common costs by increasing interconnection charges lead to less efficient allocations. And also we obtain that if the companies have different interconnection marginal cost, interconnection charge differences should be transferred to the final consumer prices, and interconnection charges should be adjusted to the companies' interconnection marginal costsAccess Charge, Telecommunication, Monopoly

Excitation mechanisms and characterization of a multi-ionic xenon laser

The emission characteristics of an ultraviolet-visible pulsed multi-ionic xenon laser were studied through time-resolved spectroscopy and the results were interpreted using a collisional-radiative theoretical model. This analysis includes more than 20 laser lines belonging to several ionic species (Xe III-VIII). Depending on the experimental conditions, different temporal distributions of the laser lines and their corresponding spontaneous emissions can be observed. In particular, laser emission presents temporal oscillations near threshold. Pumping processes for the laser transitions have been analyzed by using this model. Relativistic Hartree-Fock calculations of laser level lifetimes and radiative transition probabilities were performed. Experimental laser gain for several transitions were obtained and compared with the theoretical values derived from the calculations

Excitation Mechanisms and Characterization of a Multi-Ionic Xenon Laser

The emission characteristics of an ultraviolet-visible pulsed multi-ionic xenon laser were studied through time-resolved spectroscopy and the results were interpreted using a collisional-radiative theoretical model. This analysis includes more than 20 laser lines belonging to several ionic species (Xe III-VIII). Depending on the experimental conditions, different temporal distributions of the laser lines and their corresponding spontaneous emissions can be observed. In particular, laser emission presents temporal oscillations near threshold. Pumping processes for the laser transitions have been analyzed by using this model. Relativistic Hartree-Fock calculations of laser level lifetimes and radiative transition probabilities were performed. Experimental laser gain for several transitions were obtained and compared with the theoretical values derived from the calculation

Epidemiology, practice of ventilation and outcome for patients at increased risk of postoperative pulmonary complications

BACKGROUND Limited information exists about the epidemiology and outcome of surgical patients at increased risk of postoperative pulmonary complications (PPCs), and how intraoperative ventilation was managed in these patients. OBJECTIVES To determine the incidence of surgical patients at increased risk of PPCs, and to compare the intraoperative ventilation management and postoperative outcomes with patients at low risk of PPCs. DESIGN This was a prospective international 1-week observational study using the ‘Assess Respiratory Risk in Surgical Patients in Catalonia risk score’ (ARISCAT score) for PPC for risk stratification. PATIENTS AND SETTING Adult patients requiring intraoperative ventilation during general anaesthesia for surgery in 146 hospitals across 29 countries. MAIN OUTCOME MEASURES The primary outcome was the incidence of patients at increased risk of PPCs based on the ARISCAT score. Secondary outcomes included intraoperative ventilatory management and clinical outcomes. RESULTS A total of 9864 patients fulfilled the inclusion criteria. The incidence of patients at increased risk was 28.4%. The most frequently chosen tidal volume (VT) size was 500 ml, or 7 to 9 ml kg1 predicted body weight, slightly lower in patients at increased risk of PPCs. Levels of positive end-expiratory pressure (PEEP) were slightly higher in patients at increased risk of PPCs, with 14.3% receiving more than 5 cmH2O PEEP compared with 7.6% in patients at low risk of PPCs (P < 0.001). Patients with a predicted preoperative increased risk of PPCs developed PPCs more frequently: 19 versus 7%, relative risk (RR) 3.16 (95% confidence interval 2.76 to 3.61), P < 0.001) and had longer hospital stays. The only ventilatory factor associated with the occurrence of PPCs was the peak pressure. CONCLUSION The incidence of patients with a predicted increased risk of PPCs is high. A large proportion of patients receive high VT and low PEEP levels. PPCs occur frequently in patients at increased risk, with worse clinical outcome

Epidemiology, practice of ventilation and outcome for patients at increased risk of postoperative pulmonary complications: LAS VEGAS - An observational study in 29 countries

BACKGROUND Limited information exists about the epidemiology and outcome of surgical patients at increased risk of postoperative pulmonary complications (PPCs), and how intraoperative ventilation was managed in these patients. OBJECTIVES To determine the incidence of surgical patients at increased risk of PPCs, and to compare the intraoperative ventilation management and postoperative outcomes with patients at low risk of PPCs. DESIGN This was a prospective international 1-week observational study using the ‘Assess Respiratory Risk in Surgical Patients in Catalonia risk score’ (ARISCAT score) for PPC for risk stratification. PATIENTS AND SETTING Adult patients requiring intraoperative ventilation during general anaesthesia for surgery in 146 hospitals across 29 countries. MAIN OUTCOME MEASURES The primary outcome was the incidence of patients at increased risk of PPCs based on the ARISCAT score. Secondary outcomes included intraoperative ventilatory management and clinical outcomes. RESULTS A total of 9864 patients fulfilled the inclusion criteria. The incidence of patients at increased risk was 28.4%. The most frequently chosen tidal volume (V T) size was 500 ml, or 7 to 9 ml kg−1 predicted body weight, slightly lower in patients at increased risk of PPCs. Levels of positive end-expiratory pressure (PEEP) were slightly higher in patients at increased risk of PPCs, with 14.3% receiving more than 5 cmH2O PEEP compared with 7.6% in patients at low risk of PPCs (P ˂ 0.001). Patients with a predicted preoperative increased risk of PPCs developed PPCs more frequently: 19 versus 7%, relative risk (RR) 3.16 (95% confidence interval 2.76 to 3.61), P ˂ 0.001) and had longer hospital stays. The only ventilatory factor associated with the occurrence of PPCs was the peak pressure. CONCLUSION The incidence of patients with a predicted increased risk of PPCs is high. A large proportion of patients receive high V T and low PEEP levels. PPCs occur frequently in patients at increased risk, with worse clinical outcome.</p

Sex difference and intra-operative tidal volume: Insights from the LAS VEGAS study

BACKGROUND: One key element of lung-protective ventilation is the use of a low tidal volume (VT). A sex difference in use of low tidal volume ventilation (LTVV) has been described in critically ill ICU patients.OBJECTIVES: The aim of this study was to determine whether a sex difference in use of LTVV also exists in operating room patients, and if present what factors drive this difference.DESIGN, PATIENTS AND SETTING: This is a posthoc analysis of LAS VEGAS, a 1-week worldwide observational study in adults requiring intra-operative ventilation during general anaesthesia for surgery in 146 hospitals in 29 countries.MAIN OUTCOME MEASURES: Women and men were compared with respect to use of LTVV, defined as VT of 8 ml kg-1 or less predicted bodyweight (PBW). A VT was deemed 'default' if the set VT was a round number. A mediation analysis assessed which factors may explain the sex difference in use of LTVV during intra-operative ventilation.RESULTS: This analysis includes 9864 patients, of whom 5425 (55%) were women. A default VT was often set, both in women and men; mode VT was 500 ml. Median [IQR] VT was higher in women than in men (8.6 [7.7 to 9.6] vs. 7.6 [6.8 to 8.4] ml kg-1 PBW, P &lt; 0.001). Compared with men, women were twice as likely not to receive LTVV [68.8 vs. 36.0%; relative risk ratio 2.1 (95% CI 1.9 to 2.1), P &lt; 0.001]. In the mediation analysis, patients' height and actual body weight (ABW) explained 81 and 18% of the sex difference in use of LTVV, respectively; it was not explained by the use of a default VT.CONCLUSION: In this worldwide cohort of patients receiving intra-operative ventilation during general anaesthesia for surgery, women received a higher VT than men during intra-operative ventilation. The risk for a female not to receive LTVV during surgery was double that of males. Height and ABW were the two mediators of the sex difference in use of LTVV.TRIAL REGISTRATION: The study was registered at Clinicaltrials.gov, NCT01601223

Rationale, study design, and analysis plan of the Alveolar Recruitment for ARDS Trial (ART): Study protocol for a randomized controlled trial

Background: Acute respiratory distress syndrome (ARDS) is associated with high in-hospital mortality. Alveolar recruitment followed by ventilation at optimal titrated PEEP may reduce ventilator-induced lung injury and improve oxygenation in patients with ARDS, but the effects on mortality and other clinical outcomes remain unknown. This article reports the rationale, study design, and analysis plan of the Alveolar Recruitment for ARDS Trial (ART). Methods/Design: ART is a pragmatic, multicenter, randomized (concealed), controlled trial, which aims to determine if maximum stepwise alveolar recruitment associated with PEEP titration is able to increase 28-day survival in patients with ARDS compared to conventional treatment (ARDSNet strategy). We will enroll adult patients with ARDS of less than 72 h duration. The intervention group will receive an alveolar recruitment maneuver, with stepwise increases of PEEP achieving 45 cmH(2)O and peak pressure of 60 cmH2O, followed by ventilation with optimal PEEP titrated according to the static compliance of the respiratory system. In the control group, mechanical ventilation will follow a conventional protocol (ARDSNet). In both groups, we will use controlled volume mode with low tidal volumes (4 to 6 mL/kg of predicted body weight) and targeting plateau pressure &lt;= 30 cmH2O. The primary outcome is 28-day survival, and the secondary outcomes are: length of ICU stay; length of hospital stay; pneumothorax requiring chest tube during first 7 days; barotrauma during first 7 days; mechanical ventilation-free days from days 1 to 28; ICU, in-hospital, and 6-month survival. ART is an event-guided trial planned to last until 520 events (deaths within 28 days) are observed. These events allow detection of a hazard ratio of 0.75, with 90% power and two-tailed type I error of 5%. All analysis will follow the intention-to-treat principle. Discussion: If the ART strategy with maximum recruitment and PEEP titration improves 28-day survival, this will represent a notable advance to the care of ARDS patients. Conversely, if the ART strategy is similar or inferior to the current evidence-based strategy (ARDSNet), this should also change current practice as many institutions routinely employ recruitment maneuvers and set PEEP levels according to some titration method.Hospital do Coracao (HCor) as part of the Program 'Hospitais de Excelencia a Servico do SUS (PROADI-SUS)'Brazilian Ministry of Healt

Modelando una función de exportaciones con los precios de insumos variables independientes: una nota

Este artículo tiene por objetivo la construcción de un modelo no monetario de equilibrio general de donde se obtiene una función de exportaciones dependiente de los precios relativos de los factores. El contexto de equilibrio general permite verificar bajo qué condiciones esa función puede ser estimada econométricamente sin usar la técnica de ecuaciones simultáneas. O, en otras palabras, bajo qué condiciones de estimación, una función de exportaciones única daría estimaciones libres del sesgo debido a la correlación entre las variables independientes y los residuos. O, aún en otras palabras, como podemos ir de un análisis de equilibrio general a uno de equilibrio parcial.

Efficient capacity investment and joint production agreements in an oligopolistic electricity market: The HidroAysén joint venture project

We develop a model for a power market with the characteristics of the Chilean power supply industry, which is an integrated system with a system operator (SO) with a vast authority to define the dispatch of the system. We evaluate whether a large joint power generator project made up by the two largest power generators is an anti-competitive project. Considering four investment technologies for power generation, namely, hydro, coal, diesel, and an advantageous hydro technology which can only be built in a large scale (HidroAysén) for the joint venture case, we use an oligopolistic Cournot model and a Benevolent Social Planner, both calibrated to the Chilean power industry, in order to assess the efficiency of alternative investment strategies and conditions whether the HidroAysén joint venture project can be barred to be judged as anti-competitive. Results suggest that the joint venture is an efficient investment and there is a pro-competitive behaviour on the part of the two power generators, and that there are benefit to consumers, who should expect non-increasing energy prices as a result of the advantageous hydrotechnology.Electricity markets Game theory Strategic alliances