Social Dilemmas in Environmental Economics and Policy Considerations: A Review

Many crucial environmental issues lead to social dilemmas, in which the personally optimal solution, and the socially optimal solution diverge. Finding a solution to this dilemma is extremely important to allow a good and sustainable management of many exhaustible natural resources. This is especially true when the resource users need to develop collectively a set of rules or practices, and the institutions are unable to provide, or enforce, effective regulations. A few examples are forests, and fisheries, but also carbon emissions. This review presents a selected number of results coming from field observations, laboratory experiments, and theoretical work, which pinpoint some of the more crucial aspects of these decision environments. Knowing which incentives and situational aspects may motivate resource users to adopt a more or less cooperative behavior can potentially be of pivotal importance to develop effective policies and regulations. At the same time, the research we present is also of great interestfor any diagnostic or explorative study that aims to study direct resource users, and their development of cooperative attitudes and practices

On the Optimal Design of a Spectrum-Switched Optical Network With Multiple Modulation Formats and Rates

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Comparison of Two Reciprocating and Anatomical Single File Techniques in Cleaning Oval Anatomies

Introduction: The present study aimed to compare the capability of two single-file shaping systems in disinfecting and cleaning long oval root canals. Materials and Methods: Fifty single-rooted teeth were prepared, contaminated with Enterococcus faecalis and divided into two groups. Two samplings were obtained; S1 before chemo-mechanical preparation and S2 after the preparation. Depending on the group, chemo-mechanical preparation was performed with XP-endo Shaper (XPS) and Wave One Gold (WOG). Five teeth from each group were observed under scanning electron microscopy (1000×) to evaluate the cleanliness of root canals at 3, 6 and 9 mm from the apex. All probability (P-values) were two-tailed, statistical significance was set at 0.05 and analyses were conducted using SPSS statistical software. Results: A significant reduction in the colony forming units was observed from S1 to S2 in both tested groups. In S2, XPS group obtained significantly lower colony forming units (P<0.001). In the cleanliness study, XPS group resulted in significantly cleaner canals compared to WOG. Conclusions: Based on this in vitro study XPS system was more effective in disinfecting and cleaning long oval canals

GMPLS-Controlled Dynamic Translucent Optical Networks

The evolution of optical technologies has paved the way to the migration from opaque optical networks (i.e., networks in which the optical signal is electronically regenerated at each node) to transparent (i.e., all-optical) networks. Translucent optical networks (i.e., optical networks with sparse opto-electronic regeneration) enable the exploitation of the benefits of both opaque and transparent networks while providing a suitable solution for dynamic connections. Translucent optical networks with dynamic connections can be controlled by the GMPLS protocol suite. This article discusses the enhancements that the GMPLS suite requires for the control of dynamic translucent optical networks with quality of transmission guarantees. Such enhancements concern QoT-awareness and regenerator-awareness and can be achieved by collecting and disseminating the information on QoT and regenerator availability, respectively, and by efficiently leveraging such information for traffic engineering purposes. More specifically, the article proposes two distributed approaches, based on the routing protocol and the signaling protocol, for disseminating regenerator information in the GMPLS control plane. Moreover, three strategies are introduced to efficiently and dynamically designate the regeneration node(s) along the connection route. Routing and signaling approaches are compared in terms of blocking probability, setup time, and control plane load during provisioning and restoration

Face mask use and physical distancing before and after mandatory masking: Evidence from public waiting lines

During the COVID-19 pandemic, the introduction of mandatory face mask usage was accompanied by a heated debate. It was argued that community use of masks creates a false sense of security that could decrease social distancing, thus making matters worse. We conducted a randomized field experiment in Berlin, Germany, to investigate whether masks lead to decreases in distancing and whether this mask effect interacts with the introduction of a mask mandate in Berlin. Joining lines in front of stores, we measured the distance kept from the experimenter in two treatment conditions - the experimenter wore a mask in one and no face covering in the other - both before and after the introduction of mandatory mask use in stores. We find no evidence that mandatory masking has a negative effect on distance keeping. To the contrary, in our study, masks significantly increase distancing and the effect does not differ between the two periods. Further, we find no evidence that the mask mandate affected distancing. However, our results suggest that the relaxation of shop opening restrictions had a negative effect on distancing

Microbiological characterization and effect of resin composites in cervical lesions

Non carious cervical lesions associated to muscle hyperfunctions are increasing. Microhybrid resin composites are used to restore cervical abfractions. The purpose of this study was to investigate if resin composites modify tooth plaque, inducing an increment of cariogenic microflora and evaluate their effect, in vivo and in vitro, against S. mutans. Eight abfractions were restored with two microhybrid resin composites (Venus, Heraeus-Kulzer® and Esthet-X, Dentsply®), after gnatological therapy, in three patients with muscle hyperfunctions. For each abfraction three samples of plaque were taken from the cervical perimeter: before the restoration, one week and three months after restoration. The samples were evaluated both by traditional microbiological methods and by Polymerase Chain Reaction (PCR). In vitro, disk-shaped specimens of the two composites were prepared to estimate the effects against pre-cultured S. mutans, after incubation at 37°C for 24h and assessed by a turbidimetric technique. In vivo no differences were found in plaque growth, for all samples, before and after restoration with both composites; in vitro, instead, a significant reduction of S. mutans growth was found between specimens of two composites (Mann-Whitney U-test p>0,06). In this study a relevant consideration was elicited: composite materials, in vivo, do not modify plaque composition of non carious cervical lesions to a potential cariogenic plaque

Indirect composite restorations luted with two different procedures: a ten years follow up clinical trial

Objectives: The aim of this clinical trial was to evaluate posterior indirect composite resin restoration ten years after placement luted with two different procedures. Study Design: In 23 patients 22 inlays/onlays (Group A) were luted using a dual-cured resin composite cement and 26 inlays/onlays (Group B) were luted using a light cured resin composite for a total of 48 Class I and Class II indirect composite resin inlays and onlays. The restorations were evaluated at 2 time points: 1) one week after placement (baseline evaluation) and 2) ten years after placement using the modified USPHS criteria. The Mann- Whitney and the Wilcoxon tests were used to examine the difference between the results of the baseline and 10 years evaluation for each criteria. Results: Numerical but not statistically significant differences were noted on any of the recorded clinical parameters ( p >0.05) between the inlay/onlays of Group A and Group B. 91% and 94 % of Group A and B respectively were rated as clinically acceptable in all the evaluated criteria ten years after clinical function. Conclusions: Within the limits of the study the results showed after ten years of function a comparable clinical performance of indirect composite resin inlays/onlays placed with a light cure or dual cure luting procedures

Face masks increase compliance with physical distancing recommendations during the COVID-19 pandemic

Governments across the world have implemented restrictive policies to slow the spread of COVID-19. Recommended face mask use has been a controversially discussed policy, among others, due to potential adverse effects on physical distancing. Using a randomized field experiment (N=300), we show that individuals keep a significantly larger distance from someone wearing a face mask than from an unmasked person. According to an additional survey experiment (N=456), masked individuals are not perceived as being more infectious than unmasked ones, but they are believed to prefer more distancing. This result suggests that, in times where mask use is voluntary, wearing a mask serves as a social signal for a preferred greater distance that is respected by others. Our findings provide strong evidence against the claim that mask use creates a false sense of security that would negatively affect physical distancing

Laparoscopic Repair of a Posttraumatic Left-Sided Diaphragmatic Hernia Complicated by Strangulation and Colon Obstruction

Posttraumatic diaphragmatic hernia complicated with colonic obstruction can be managed by experienced surgeons with minimally invasive methods