Privatization and Efficiency: from Principals and Agents to Political Economy

We survey the theoretical literature on privatization and efficiency by tracing its evolution from the applications of agency theory to recent contributions in the field of political economy. The first ones extend the theory of regulation with incomplete information to address privatization issues, comparing State Owned Entreprises (SOEs) with private regulated firms. The benefits of privatization may either derive from the constraints it places on malevolent agents or to the impossibility of commitment by a benevolent government because of incomplete contracts. Contributions dealing with political economy issues separate privatization from restructuring decisions. They either explore bargaining between managers and politicians or analyze the impact of privatization shaped by political preferences on efficiency. The theoretical results regarding the relation between privatization and efficiency do not lead to any definitive conclusion. Privatization may increase productive efficiency when restructuring takes place whereas its effects on allocative efficiency still remain uncertain.Regulation, Imperfect Information, Political Preferences

Efficient Mechanisms for Access to Storage with Imperfect Competition in Gas Markets

Scarce storage capacity and distortions in access to gas storage are considered causes of market foreclosure in liberalized gas markets. We consider rules currently adopted in Europe for storage rationing and propose efficient rationing mechanism based on the value of storage, when other flexibility inputs are available. Firstly we analyse productive efficiency issues neglecting vertical restraints and strategic behaviour in the final market. Then we assume imperfect compettion in the downstream market for gas supplies, given the avaialbility of storage capacity upstream. We consider effciency issues in a two stage model comparing regulated storage tariffs – coupled with a centralizedrationing mechanism – with storage auctions. Finally we consider as an optimal mechanism the allocation of storage arising from welfare maximization by a social planner. We find that it is usually optimal to maximize the amount of storage capacity allocated to new entrants in the gas markets. Storage auctions deviates from the optimal mechanism, but still improve efficiency, with respect to current mechanisms, to the extent that they allocate storage according to its value. Furthermore storage allocation appear to be an extremeley powerful mechanism to improve competition and efficiency in gas markets.Liberalization, Auctions, Essential Facilities

Use of balloon catheter dilation and steroid-eluting stent in light and severe rhinosinusitis of frontal sinus: a multicenter retrospective randomized study

OBJECTIVE: Frontal sinus surgery has an increased rate of re-stenosis, if compared to other sinuses, that mainly depends on recurrent inflammation and abnormal scarring at the frontal recess; its reduction represents one of the keys of therapeutic success. Balloon catheter dilation (BCD) and implantable sinus stents/spacers represent strategies to improve sinus ventilation respecting the integrity of mucosa and reducing abnormal post-surgical scarring. The purpose of this study is to evaluate the effectiveness, safety and correct indication for the use of BCD and a non-absorbable stent (Relieva Stratus™ MicroFlow spacer) in the management of chronic rhinosinusitis (CRS) of the frontal sinus. PATIENTS AND METHODS: In this multicentric retrospective study we included a population of 76 frontal sinuses with non-polypoid CRS. Forty-one frontal sinuses were treated with BCD alone and 35 with BCD + Spacer. We analysed both radiological (Lund-McKay CT scoring modified by Zienrich) and symptomatologic results (SNOT-20 questionnaire) before surgery and after 12 months, dividing patients in two main groups: group “L” (light/mild frontal CRS) and group “S” (moderate/severe frontal CRS). RESULTS: Our results confirm a good safety and effectiveness of BCD in management of frontal CRS and show a good safety, although without significant effectiveness, of Relieva Stratus™ MicroFlow spacer when added to BCD in the management of light and severe frontal CRS. CONCLUSIONS: BCD is an option in management of frontal CRS; the use of stents/spacers could become a new and effective tool in management of CSR, both in addition to standard therapies and in patients where the use of systemic drugs is contraindicated

Prognostic Value of Coronary Calcium Score in Asymptomatic Individuals: A Systematic Review

Despite updated guidelines and technological developments that allow for an accurate diagnosis, many asymptomatic individuals have a high risk of developing CAD or cardiac events. The CAC score can estimate a correct risk level for these subjects, which is clinically significant for adequate management of risk factors and obtaining personalized preventive therapy. This systematic review aims to assess the prognostic value of CAC score in asymptomatic individuals. According to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement, a systematic literature search was performed to identify original articles since 2010 that evaluated the prognostic value of CAC score in asymptomatic individuals. The quality of the included studies was assessed by the QUIPS tool. A total of 45 articles were selected. Many of these (25 studies) evaluated the prognostic value of CAC score in asymptomatic subjects. In comparison, others (20 studies) evaluated the association of CAC score with other clinical parameters and imaging modalities or the comparison with computed tomography coronary angiography (CTCA). Our findings showed that the CAC score provides valuable prognostic information for predicting CAD risk in asymptomatic individuals

Current status of the self-expandable metal stent as a bridge to surgery versus emergency surgery in colorectal cancer. Results from an updated systematic review and meta-analysis of the literature

Background: The current use of endoscopic stenting as a bridge to surgery is not always accepted in standard clinical practice to treat neoplastic colonic obstructions. Objectives: The role of colonic self-expandable metal stent (SEMS) positioning as a bridge to resective surgery versus emergency surgery (ES) for malignant obstruction, using all new data and available variables, was studied and we focused on short- and long-term results. Materials and Methods: A systematic review with meta-analysis was performed. PubMed, SCOPUS and Web of Science databases were included. The search comprised only randomized controlled trials (RCTs) investigating the interventions that included SEMS positioning versus ES. The primary outcomes were the rates of overall postoperative mortality, clinical and technical success. The secondary outcomes were the short- and long-term results. Results: A total of 12 studies were eligible for further analyses. A laparoscopic colectomy was the most common operation performed in the SEMS group, whereas the traditional open approach was commonly used in the ES group. Intraoperative colonic lavage was seldomly performed during ES. There were no differences in mortality rates between the two groups (RR 1.06, 95% CI 0.55 to 2.04; I2 = 0%). In the SEMS group, the rate of successful primary anastomosis was significantly higher in of SEMS (69.75%) than in the ES (55.07%) (RR 1.26, 95% 245 CI 1.01 to 1.57; I2 = 86%). Conversely, the upfront Hartmann procedure was performed more frequently in the ES (39.1%) as compared to the SEMS group (23.4%) (RR 0.61, 95% CI 0.45 to 0.85; I2 = 23%). The overall postoperative complications rate was significantly lower in the SEMS group (32.74%) than in the ES group (48.25%) (RR 0.61, 95% CI 0.41 to 0.91; I2 = 65%). Conclusions: In the presence of malignant colorectal obstruction, SEMS is safe and associated with the same mortality and significantly lower morbidity than the ES group. The rate of successful primary anastomosis was significantly higher than the ES group. Nevertheless, recurrence and survival outcomes are not significantly different between the two groups. The analysis of short- and long-term results can suggest the use of SEMS as a bridge to resective surgery when it is performed by an endoscopist with adequate expertise in both colonoscopy and fluoroscopic techniques and who performed commonly colonic stenting

Laparoscopic peritoneal lavage: A definitive treatment for diverticular peritonitis or a "bridge" to elective laparoscopic sigmoidectomy?

To this day, the treatment of generalized peritonitis secondary to diverticular perforation is still controversial. Recently, in patients with acute sigmoid diverticulitis, laparoscopic lavage and drainage has gained a wide interest as an alternative to resection. Based on this backdrop, we decided to perform a systematic review of the literature to evaluate the safety, feasibility, and efficacy of peritoneal lavage in perforated diverticular disease. A bibliographic search was performed in PubMed for case series and comparative studies published between January 1992 and February 2014 describing laparoscopic peritoneal lavage in patients with perforated diverticulitis. A total of 19 articles consisting of 10 cohort studies, 8 case series, and 1 controlled clinical trial met the inclusion criteria and were reviewed. In total these studies analyzed data from 871 patients. The mean follow-up time ranged from 1.5 to 96 months when reported. In 11 studies, the success rate of laparoscopic peritoneal lavage, defined as patients alive without surgical treatment for a recurrent episode of diverticulitis, was 24.3%. In patients with Hinchey stage III diverticulitis, the incidence of laparotomy conversion was 1%, whereas in patients with stage IV it was 45%. The 30-day postoperative mortality rate was 2.9%. The 30-day postoperative reintervention rate was 4.9%, whereas 2% of patients required a percutaneous drainage. Readmission rate after the first hospitalization for recurrent diverticulitis was 6%. Most patients who were readmitted (69%) required redo surgery. A 2-stage laparoscopic intervention was performed in 18.3% of patients. Laparoscopic peritoneal lavage should be considered an effective and safe option for the treatment of patients with sigmoid diverticulitis with Hinchey stage III peritonitis; it can also be consider as a “bridge” surgical step combined with a delayed and elective laparoscopic sigmoidectomy in order to avoid a Hartmann procedure. This minimally invasive staged approach should be considered for patients without systemic toxicity and in centers experienced in minimally invasive surgery techniques. Further evidence is needed, and the ongoing RCTs will better define the role of the laparoscopic peritoneal lavage/drainage in the treatment of patients with complicated diverticulitis

A study of the galaxy redshift distribution toward the cosmic microwave background cold spot in the Corona Borealis supercluster

We present a study of the spatial and redshift distributions of Sloan Digital Sky Survey (SDSS) galaxies toward the position of CrB-H, a very deep and extended decrement in the Cosmic Microwave Background (CMB), located within the Corona Borealis supercluster (CrB-SC). It was found in a survey with the Very Small Array (VSA) interferometer at 33 GHz, with a peak negative brightness temperature of -230 muK, and deviates 4.4-sigma from the Gaussian CMB (G\'enova-Santos et al.). Observations with the Millimeter and Infrared Testa Grigia Observatory (MITO) suggested that 25$^+21_-18% of this decrement may be caused by the thermal Sunyaev-Zel'dovich (tSZ) effect (Battistelli et al.). Here we investigate whether the galaxy distribution could be tracing either a previously unnoticed galaxy cluster or a Warm/Hot Intergalactic Medium (WHIM) filament that could build up this tSZ effect. We find that the projected density of galaxies outside Abell clusters and with redshifts 0.05<z<0.12 at the position of CrB-H is the highest in the area encompassed by the CrB-SC. Most of these galaxies are located around redshifts z=0.07 and z=0.11, but no clear connection in the form of a filamentary structure is appreciable in between. While the galaxy distribution at z=0.07 is sparse, we find evidence at z=0.11 of a galaxy group or a low-mass galaxy cluster. We estimate that this structure could produce a tSZ effect of ~ -18 muK. The remaining VSA signal of ~ -212 muK is still a significant 4.1-sigma deviation from the Gaussian CMB. However, the MITO error bar allows for a larger tSZ effect, which could be produced by galaxy clusters or superclusters beyond the sensitivity of the SDSS. Contributions from other possible secondary anisotropies associated with these structures are also discussed.Comment: 11 pages, 5 figures, 3 tables. Accepted in MNRA

Dual Source Photon-Counting Computed Tomography-Part II: Clinical Overview of Neurovascular Applications

Photon-counting detector (PCD) is a novel computed tomography detector technology (photon-counting computed tomography-PCCT) that presents many advantages in the neurovascular field, such as increased spatial resolution, reduced radiation exposure, and optimization of the use of contrast agents and material decomposition. In this overview of the existing literature on PCCT, we describe the physical principles, the advantages and the disadvantages of conventional energy integrating detectors and PCDs, and finally, we discuss the applications of the PCD, focusing specifically on its implementation in the neurovascular field