187 research outputs found

    Corruption and Positive Selection in Privatization

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    We consider the supply of a public good based on a publicly-owned facility. The Government has a choice between provision in-house and privatizing the facility and then outsourcing the production. In particular, we focus on corruption in the decision to privatize and on its effect on social welfare when there is asymmetric information on the public and private manager's efficiency. Our analysis shows that a corrupt Government, that chooses to privatize only in exchange for a bribe, makes a positive selection on the private firm's efficiency and, thus, may raise expected social welfare above what an honest Government could get.Corruption, Privatization, Private vs. public provision.

    Response of key stress-related genes of the seagrass Posidonia oceanica in the vicinity of submarine volcanic vents

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    Submarine volcanic vents are being used as natural laboratories to assess the effects of increased ocean acidity and carbon dioxide (CO2) concentration on marine organisms and communities. However, in the vicinity of volcanic vents other factors in addition to CO2, which is the main gaseous component of the emissions, may directly or indirectly confound the biota responses to high CO2. Here we used for the first time the expression of antioxidant and stress-related genes of the seagrass Posidonia oceanica to assess the stress levels of the species. Our hypothesis is that unknown factors are causing metabolic stress that may confound the putative effects attributed to CO2 enrichment only. We analyzed the expression of 35 antioxidant and stress-related genes of P. oceanica in the vicinity of submerged volcanic vents located in the islands of Ischia and Panarea, Italy, and compared them with those from control sites away from the influence of vents. Reverse-transcription quantitative polymerase chain reaction (RT-qPCR) was used to characterize gene expression patterns. Fifty-one percent of genes analyzed showed significant expression changes. Metal detoxification genes were mostly down-regulated in relation to controls at both Ischia and Panarea, indicating that P. oceanica does not increase the synthesis of heavy metal detoxification proteins in response to the environmental conditions present at the two vents. The up-regulation of genes involved in the free radical detoxification response (e.g., CAPX, SODCP and GR) indicates that, in contrast with Ischia, P. oceanica at the Panarea site faces stressors that result in the production of reactive oxygen species, triggering antioxidant responses. In addition, heat shock proteins were also activated at Panarea and not at Ischia. These proteins are activated to adjust stress-accumulated misfolded proteins and prevent their aggregation as a response to some stressors, not necessarily high temperature. This is the first study analyzing the expression of target genes in marine plants living near natural CO2 vents. Our results call for contention to the general claim of seagrasses as "winners" in a high-CO2 world, based on observations near volcanic vents. Careful consideration of factors that are at play in natural vents sites other than CO2 and acidification is required. This study also constitutes a first step for using stress-related genes as indicators of environmental pressures in a changing ocean.project HighGrass "High-CO2 effects on seagrass photosynthetic ecophysiology" [PTDC/MAREST/3687/2012]; MIUR Italian flagship project RITMARE; ESF COST Action "Seagrass Productivity: from genes to ecosystem management

    Nitric oxide in marine photosynthetic organisms

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    Nitric oxide is a versatile and powerful signaling molecule in plants. However, most of our understanding stems from studies on terrestrial plants and very little is known about marine autotrophs. This review summarizes current knowledge about the source of nitric oxide synthesis in marine photosynthetic organisms and its role in various physiological processes under normal and stress conditions. The interactions of nitric oxide with other stress signals and cross talk among secondary messengers are also highlighted

    Endovascular treatment of penetrating atherosclerotic ulcers of the arch and thoracic aorta: In-hospital and 5-year outcomes

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    Objective: Thoracic endovascular aortic repair (TEVAR) is the treatment of choice for thoracic aorta diseases including penetrating aortic ulcer (PAU). The objective of this study was to analyze the results of TEVAR for the treatment of PAU in our population. Methods: From January 1999 to January 2019, 830 patients with type B aortic syndromes were treated with TEVAR in our institution. Of these we selected 73 patients treated for a PAU. Clinical and radiologic follow-up was performed in all patients. Results: Mean age of our population was 72 Ā± 8 years. Fifteen patients (20.5%) were treated in an emergency setting. The proximal landing zone was in arch zone 2 in 22 patients (30.1%). In-hospital mortality was 6.8% and was associated with acute presentation (P = .005). Distal arch delivery of the endograft was unrelated to mortality (Fisher exact test, P = .157). Survival at 1 and 5 years was 81.7% and 67.3%, respectively. Sixteen patients underwent reintervention of the thoracic aorta. Patients who underwent emergency surgery and older patients had a shorter survival (log rank test, P < .001). No difference in survival was shown according to the proximal landing zone (log rank P = .292) or the dimension of the thoracic aorta (log rank P = .067). In multivariable Cox regression analysis, only age older than 75 years was associated with 5-year mortality (hazard ratio, 6.60; 95% CI, 2.12-20.56); P < .001). Conclusions: The use of TEVAR for treatment of aortic PAU is a safe procedure in an elective setting despite necessity of arch stent grafting. An early intervention performed at smaller aortic diameters of <55 mm might be beneficial in selected patients to improve late survival

    Physiological and biochemical analyses shed light on the response of <i>Sargassum vulgare</i> to ocean acidification at different time scales

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    Studies regarding macroalgal responses to ocean acidification (OA) are mostly limited to short-term experiments in controlled conditions, which hamper the possibility to scale up the observations to long-term effects in the natural environment. To gain a broader perspective, we utilized volcanic CO2 vents as a ā€œnatural laboratoryā€ to study OA effects on Sargassum vulgare at different time scales. We measured photosynthetic rates, oxidative stress levels, antioxidant contents, antioxidant enzyme activities, and activities of oxidative metabolic enzymes in S. vulgare growing at a natural acidified site (pH 6.7) compared to samples from a site with current pH (pH 8.2), used as a control one. These variables were also tested in plants transplanted from the control to the acidified site and vice-versa. After short-term exposure, photosynthetic rates and energy metabolism were increased in S. vulgare together with oxidative damage. However, in natural populations under long-term conditions photosynthetic rates were similar, the activity of oxidative metabolic enzymes was maintained, and no sign of oxidative damages was observed. The differences in the response of the macroalga indicate that the natural population at the acidified site is adapted to live at the lowered pH. The results suggest that this macroalga can adopt biochemical and physiological strategies to grow in future acidified oceans

    Physiological and biochemical analyses shed light on the response of sargassum vulgare to ocean acidification at different time scales

    Get PDF
    Studies regarding macroalgal responses to ocean acidification (OA) are mostly limited to short-term experiments in controlled conditions, which hamper the possibility to scale up the observations to long-term effects in the natural environment. To gain a broader perspective, we utilized volcanic CO2 vents as a ā€œnatural laboratoryā€ to study OA effects on Sargassum vulgare at different time scales. We measured photosynthetic rates, oxidative stress levels, antioxidant contents, antioxidant enzyme activities, and activities of oxidative metabolic enzymes in S. vulgare growing at a natural acidified site (pH 6.7) compared to samples from a site with current pH (pH 8.2), used as a control one. These variables were also tested in plants transplanted from the control to the acidified site and vice-versa. After short-term exposure, photosynthetic rates and energy metabolism were increased in S. vulgare together with oxidative damage. However, in natural populations under long-term conditions photosynthetic rates were similar, the activity of oxidative metabolic enzymes was maintained, and no sign of oxidative damages was observed. The differences in the response of the macroalga indicate that the natural population at the acidified site is adapted to live at the lowered pH. The results suggest that this macroalga can adopt biochemical and physiological strategies to grow in future acidified oceans

    Serum HMGB1 levels are independently associated with glucose clamp-derived measures of insulin resistance in women with PCOS

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    Purpose: PCOS is associated with low grade inflammation which could play a role in insulin resistance and ovarian dysfunction. Preliminary findings suggested that serum levels of HMGB1, a cytokine involved in inflammation, might be altered in women with PCOS. Primary aim of this study was to assess whether HMGB1 serum concentrations are associated with PCOS and with the state of insulin resistance of these women. Methods: Sixty women with PCOS, selected to have a similar proportion of subjects with altered or normal insulin sensitivity, and 29 healthy controls were studied. Serum HMGB1 levels were compared in subgroups of PCOS women and controls. In PCOS women, insulin sensitivity was assessed by the glucose clamp technique and HMGB1 was measured at baseline and after acute hyperinsulinemia. Results: HMGB1 levels were similar in women with PCOS and controls and no elements used for diagnosing PCOS were associated with serum HMGB1. However, HMGB1 concentrations were higher in insulin-resistant vs insulin-sensitive PCOS women (pā€‰=ā€‰0.017), and inversely associated with insulin-induced total and non-oxidative glucose metabolism. In both subgroups of PCOS women, serum HMBG1 levels significantly increased after acute hyperinsulinemia. Conclusions: These data suggest that HMGB1 levels are not associated with PCOS per se, but with insulin resistance. Further research should establish the underlying nature of this relationship, and whether this protein might play a role in the metabolic complications of PCOS

    Quantum Interference Effects in Electronic Transport through Nanotube Contacts

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    Quantum interference has dramatic effects on electronic transport through nanotube contacts. In optimal configuration the intertube conductance can approach that of a perfect nanotube (4e2/h4e^2/h). The maximum conductance increases rapidly with the contact length up to 10 nm, beyond which it exhibits long wavelength oscillations. This is attributed to the resonant cavity-like interference phenomena in the contact region. For two concentric nanotubes symmetry breaking reduces the maximum intertube conductance from 4e2/h4e^2/h to 2e2/h2e^2/h. The phenomena discussed here can serve as a foundation for building nanotube electronic circuits and high speed nanoscale electromechanical devices
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