The Effect of Inner Mobility of Shops on Tax Revenue

In this note we consider a simple model of a service sector. In this service sector there are two types of shops, each offering distinct services at differential prices with fixed cost possibly being also unequal. When the decrease of customers is experienced by one of these two types, not both, then having less profits, those shops belonging to the damaged type can shift to the other type, thus alleviating losses on the whole. This can also mitigate the effect on tax revenue. The typical sector which the authors have in mind is that of pubs and restaurants where two types are the 'first-rate (more expensive with more services)' and the 'popular' class. Based on this model, we conduct an elementary comparative statics analysis. Most results are natural consequences, which can be inferred without using equations. And yet we supply proofs based upon equations and inequalities. Our main result is that with migration between two groups, the sector may incur less loss against the decrease in customers, especially that in the first-rate class. This means the effect on tax revenue is also milder with shiftability. Our model in this note is quite restrictive because the size of customers is exogenously given and does not respond to price differentials. Moreover in the analysis of comparative statics, the number of shops is fixed with no entry and no bankruptcy. These constraints should be removed in a more general framework

Ionic Liquid Electrospray Thruster with Two-Stage Electrodes On Glass Substrate

2023 IEEE 36th International Conference on Micro Electro Mechanical Systems (MEMS), 15-19 Jan. 2023.This paper reports ion emission of an ionic liquid electrospray thrustor with two-stage electrodes made on glass substrate having through hole for low-cost micro/nano satellites. By using the two-stage electrodes, one for ion extraction and the other for acceleration, high and stable ion emission and propulsion force is obtained. The emitter array was fabricated on a silicon wafer and the electrodes were fabricated on both sides of a glass substrate. The ion emission test was conducted, and the emission current was observed successfully. Almost no ions were collected on the accelerator electrode and reached to the collector electrode, which demonstrates the advantage of the two-stage configuration

Accuracy of Length of Virtual Stents in Treatment of Intracranial Wide-Necked Aneurysms.

Background and purposePrecise stent deployment is important for successful treatment of intracranial aneurysms by stent-assisted coiling (SAC). We evaluated the accuracy of virtual stents generated using commercial stent planning software by comparing the length of virtual and actually deployed intracranial laser cut stents on three-dimensional digital subtraction angiography (3D-DSA) images.MethodsWe retrospectively analyzed the data of 75 consecutive cases of intracranial wide-necked aneurysms treated with the SAC technique using laser cut stents. Based on 3D-DSA images acquired by C-arm CT, stent sizing and placement were intraoperatively simulated by a commercial software application. The difference in length of the stents was estimated by measuring proximal discrepancies between the end points of the virtual and actually deployed stents on fused pre-procedural and post-procedural 3D-DSA images. Discrepancies between distal stent end points were manually minimized. The Kruskal-Wallis test was applied to test whether stent location, type, and length had an effect on difference in length between virtual and real stent.ResultsThe median difference in length between virtual and real stents was 1.58 mm with interquartile range 1.12-2.12 mm. There was no evidence for an effect of stent location (p = 0.23), stent type (p = 0.33), or stent length (p = 0.53) on difference in length between virtual and real stents.ConclusionsStent planning software allows 3D simulation of laser cut stents overlain on 3D-DSA images of vessels and may thus be useful for stent selection and deployment of laser cut stents during stent-assisted coiling of intracranial aneurysms