Pay-What-You-Want Pricing in the Digital Product Marketplace: A Feasible Alternative to Piracy Prevention?

In pay-what-you-want (PWYW) pricing, buyers are allowed to pay any amount they want, often including a price of zero. Standard theory predicts that buyers are driven solely by their own interest and will always choose to pay nothing, making PWYW pricing impractical to use. Nonetheless, PWYW pricing has been consistently occurring in the marketplace. We build and analyze a theoretical model to explain the presence of PWYW pricing in the marketplace and identify the situations under which businesses are better off adopting it over the traditional posted pricing. Because the digital product domain is a particularly good fit for PWYW pricing because of its constant exposure to piracy threats, we focus on digital product firms and examine PWYW pricing as an alternative to their piracy prevention efforts. We show that PWYW pricing becomes a superior pricing strategy when the pirate version is quite similar to the authentic product and it is costly for the firm to improve its product quality. Moreover, if network externalities are present, PWYW pricing can outperform posted pricing only when the network externalities are weak. The results explain why PWYW pricing is rare in the established digital product marketplace, which exhibits strong network externalities.

Use of ABC/2 method for rapidly estimating the target mismatch on computed tomography perfusion imaging in patients with acute ischemic stroke

Background Target mismatch (ischemic core, mismatch volume and mismatch ratio) in patients with acute ischemic stroke (AIS) highly relies on the automated perfusion analysis software. Purpose To evaluate the feasibility and accuracy of using the ABC/2 method to rapidly estimate the target mismatch on computed tomography perfusion (CTP) imaging in patients with AIS, using RAPID results as a reference. Material and Methods In total, 243 patients with anterior circulation AIS who underwent CTP imaging were retrospectively reviewed. Target mismatch associated perfusion parameters were derived from RAPID results and calculated using the ABC/2 method. Paired t-test was used to assess the difference of volumetric parameters between the two methods. The ability of using the ABC/2 method to predict the important cutoff volumetric metrics was also evaluated. Result There was no significant difference in the volumes of ischemic core ( P = 0.068), ischemic area ( P = 0.209), and mismatch volume ( P = 0.518) between ABC/2 and RAPID. Using RAPID results as reference, the ABC/2 method showed high accuracy for predicting perfusion parameters (70 mL and 90 mL: sensitivity=98.5% and 98.5%, specificity=100% and 100%, positive predictive value [PPV]=100% and 100%, negative predictive value [NPV]=93.8% and 92.9%; 10 mL and 15mL: sensitivity=99.6% and 99.5%, specificity=55.6% and 50.0%, PPV=96.6% and 94.8%, NPV=90.9% and 92.3%; 1.2 and 1.8: sensitivity=99.6% and 94.8%, specificity=75.0% and 96.9%, PPV=98.7% and 99.5%, NPV=90.0% and 73.8%). Conclusion The ABC/2 method may be a feasible alternative to RAPID for estimation of target mismatch parameters on CTP in patients with AIS.

Drone-Based Water Level Detection in Flood Disasters

Japan was hit by typhoon Hagibis, which came with torrential rains submerging almost eight-thousand buildings. For fast alleviation of and recovery from flood damage, a quick, broad, and accurate assessment of the damage situation is required. Image analysis provides a much more feasible alternative than on-site sensors due to their installation and maintenance costs. Nevertheless, most state-of-art research relies on only ground-level images that are inevitably limited in their field of vision. This paper presents a water level detection system based on aerial drone-based image recognition. The system applies the R-CNN learning model together with a novel labeling method on the reference objects, including houses and cars. The proposed system tackles the challenges of the limited and wild data set of flood images from the top view with data augmentation and transfer-learning overlaying Mask R-CNN for the object recognition model. Additionally, the VGG16 network is employed for water level detection purposes. We evaluated the proposed system on realistic images captured at disaster time. Preliminary results show that the system can achieve a detection accuracy of submerged objects of 73.42% with as low as only 21.43 cm error in estimating the water level.

Algae Based Bio-Plastics: Future of Green Economy

Plastic has become one of the most crucial requirements of the modern-day living. The continuous reliance on the petroleum-based, non-biodegradable plastics has resulted in increased global environmental damage and rapid depletion of fossil fuels. Bioplastic, with remarkably similar properties to petroleum-based plastics is a promising alternative to overcome these emerging challenges. Despite the fact that algae and cyanobacteria are feasible alternative source for bio-plastic, there have been limited studies on strain selection and optimization of culture conditions for the bio plastic production. Naturally, algae and cynobacteria can accumulate higher amount of metabolites under stress conditions however one of the recent study on genetic engineering of Synechocystis sp. coupled with abiotic stresses showed up to 81% of increase in PHB level in the transformed lines. This chapter provides summary of various studies done in the field of algal bio-plastics, including bioplastic properties, genetic engineering, current regulatory framework and future prospects of bioplastic. Further the applications of bioplastics in industrial sector as well as opportunities and role of bio plastic in green economy are also discussed.

Gluten-Free Pasta Enriched with Fish By-Product for Special Dietary Uses: Technological Quality and Sensory Properties

Gluten-free pasta enriched with fish can support a nutritive and suitable option for people with celiac disease that allows achieving the benefits of fish consumption, especially the consumption of Ω-3 fatty acids; however, this requires that the pasta has adequate technological and sensory properties. For this purpose, four optimal formulations, obtained with an iterative process, were analyzed to determine the effect of the different ingredients (yellow corn flour, white corn flour, and rice flour) in gluten-free pasta compared to commercial wheat pasta. An evaluation of the color, texture, and technological properties were conducted, and the pasta was sensorially characterized. The enriched gluten-free pasta required shorter cooking times (≈3 min) and was characterized by lower hardness, springiness, gumminess, chewiness, and fracturability, and had higher values of adhesiveness than wheat pasta. In addition, the incorporation of yellow corn gives gluten-free pasta a similarity in color to commercial pasta, with a value of ∆E between 5.5 and 8.0. Regarding the sensory analysis, gluten-free pasta was characterized by slight fishy aromas and flavors with some aftertaste compared to commercial pasta. Finally, the use of different cereals to obtain gluten-free pasta could be a good and feasible alternative despite the technological and sensory modifications observed.

Optimization of Wind Sail using Computational Fluid Dynamics Simulation

The marine industry is highly dependent on oil as the fuel and the increased consumption of this fast-depleting oil recourse creates a shortage of fuel for the future as well as pollutes the environment. The pollution of water bodies also seriously affects marine life. Thus, the need for an alternate sustainable fuel source is of great importance. One such feasible alternative energy source is wind energy. The abundance, free availability and ease of conversion make it an ideal alternative to oil. Wind energy can be extracted by wind turbines or by sails. The sails convert the wind energy directly into energy for propulsion. The challenge in the conversion is the relative angle of attack of wind on the sail. The wind cannot be expected to be always in the direction of the course of the ship. When the wind is at an angle to the direction of the course, the thrust in the course director will be reduced and a component of thrust is developed on the sail which shifts the course of the ship. Bringing the ship back to the original course will create an additional expenditure of fuel. In such circumstances modification of the sail section shape from its conventional form to an optimal form helps to reduce these deficiencies. Therefore, the effort here is to numerically analyze the aerodynamic characteristics of wing-sails and to optimize their shape. The aerofoil NACA 0018 used here was chosen through a high fidelity two-dimensional computational analysis which was done earlier. The tip of the NACA 0018 was further modified by tilting it through different angles and at different chord positions forming a flap. The main objective of the study is to optimize the angle and the position of the flap relative to the chord of the aerofoil. The flapped airfoils were formed by modifying them from 10% chord length to 60% chord length. That flap angle was also varied from 0 degrees to 50 degrees in steps of 10- deg. The angle of attack on the sail was varied from 0 to 10 degrees in steps of 2 degrees. The thrust in the direction of course and the lateral thrust of each of these sail sections were estimated, tabulated and graphs were plotted. Analyzing these, an optimum shape for the sail section is derived.

Vinasse: from a residue to a high added value biopolymer

This work aimed to study the feasibility of using vinasse for polyhydroxybutyrate (PHB) production by Bacillus megaterium. To optimize the culture medium, a Box–Behnken design was employed considering carbon (C), nitrogen (N), and phosphorus (Ph) concentrations as independent variables and PHB productivity as the response variable. The productivity decreased when C or N were increased, probably due to the presence of phenolic compounds and the limitation of N for the production of PHB by Bacillus sp. bacteria. An additional experimental design to optimize the C/N ratio and growing conditions (fermentation time and temperature) was carried out. Fermentation time had a statistically significant effect on PHB productivity reaching 10.6 mg/L h. On the other hand, the variability in physicochemical properties of vinasse samples led to significant differences in PHB productivity. Lower productivity values were obtained when vinasse had higher values of DBO. Therefore, biopolymers production from vinasse is a feasible alternative to valorize this bioethanol by-product. Graphical Abstract

Modified vein clamping technique for renal cell carcinoma complicated with level I–II IVC thrombi: a study at a single centre

Objectives To share our initial experience with the modified vein clamping technique for the treatment of renal cell carcinoma complicated with level I–II IVC thrombi. Methods From March 2018 to April 2021, 11 patients with renal cell carcinoma (RCC) involving an IVC tumour thrombus were admitted to our hospital. They all underwent laparoscopic radical nephrectomy and IVC thrombectomy (LRN-IVCTE) using a modified vein clamping technique. Results All procedures were successfully completed without conversion to open surgery. The median operative time was 185.00 min (145.00–216.00 min); the median estimated blood loss was 200.00 ml (155.00–300.00 ml), and four patients received an intraoperative transfusion. In addition, the median IVC clamping time was 18.00 min (12.00–20.00 min); the median postoperative hospital stay was 6.00 days (4.00–7.00 days), while the median follow-up period was 28.00 months (4.00–34.00 months). Conclusions The modified vein clamping technique for the treatment of renal cell carcinoma complicated with level I–II IVC thrombi may be a safe and technically feasible alternative technique.

Different Charging Strategies for Electric Vehicle Fleets in Urban Freight Transport

The transition from diesel-driven urban freight transport towards more electric urban freight transport turns out to be challenging in practice. A major concern for transport operators is how to find a reliable charging strategy for a larger electric vehicle fleet that provides flexibility based on different daily mission profiles within that fleet, while also minimizing costs. This contribution assesses the trade-off between a large battery pack and opportunity charging with regard to costs and operational constraints. Based on a case study with 39 electric freight vehicles that have been used by a parcel delivery company and a courier company in daily operations for over a year, various scenarios have been analyzed by means of a TCO analysis. Although a large battery allows for more flexibility in planning, opportunity charging can provide a feasible alternative, especially in the case of varying mission profiles. Additional personnel costs during opportunity charging can be avoided as much as possible by a well-integrated charging strategy, which can be realized by a reservation system that minimizes the risk of occupied charging stations and a dense network of charging stations.