Using non-homogeneous point process statistics to find multi-species event clusters in an implanted semiconductor

The Poisson distribution of event-to-ith-nearest-event radial distances is well known for homogeneous processes that do not depend on location or time. Here we investigate the case of a non-homogeneous point process where the event probability (and hence the neighbour configuration) depends on location within the event space. The particular non-homogeneous scenario of interest to us is ion implantation into a semiconductor for the purposes of studying interactions between the implanted impurities. We calculate the probability of a simple cluster based on nearest neighbour distances, and specialise to a particular two-species cluster of interest for qubit gates. We show that if the two species are implanted at different depths there is a maximum in the cluster probability and an optimum density profile

Information Costs and Reverse Payment Settlements: Bridging the Gap Between the Courts and the Antitrust Agencies

Reverse payment settlements have attracted increased scrutiny due to the controversial presence of a payment from a brand-name drug company to a generic company that is ostensibly preparing to infringe on the branded company’s patent. The antitrust agencies and the courts settled into an intergovernmental stalemate regarding the appropriate framework of analysis to apply when reviewing antitrust challenges to these settlements. The FTC and DOJ have viewed the deals skeptically as a vehicle for competitors to split monopoly profits, but the lower courts have generally been deferential to what they identified as an exercise of a patent holder’s lawful right to exclude. Much has been written about which side is correct, yet there has been relatively little exploration of the source of the persistent disagreement. Building off of Henry Smith’s property rights theory and the cognitive miser literature from Peter Lee, this Article explains that the long-standing disagreement stems from the judiciary’s application of information-cost-saving rules. Courts adopted a formalistic approach that would almost invariably uphold a reverse payment settlement because they tend to apply bright-line rules when dealing with property rights, and they are prone to adjudicate complex patent and patent-related cases in ways that economize on the costs of information processing. Although the Supreme Court resolved the disagreement by adopting a more information-demanding rule of reason approach in FTC v. Actavis, the cognitive miser phenomenon will continue to affect how courts adjudicate antitrust challenges to reverse-payment settlements

Enhanced diffusion and bound exciton interactions of high density implanted bismuth donors in silicon

This study reports the effect of an increasing ion dose on both the electrical activation yield and the characteristic properties of implanted bismuth donors in silicon. A strong dependence of implant fluence is observed on both the yield of bismuth donors and the measured impurity diffusion. This is such that higher ion concentrations result in both a decrease in activation and an enhancement in donor migration through interactions with mobile silicon lattice vacancies and interstitials. Furthermore, the effect of implant fluence on the properties of the Si:Bi donor bound exciton, D0X, is also explored using photoluminescence (PL) measurements. In the highest density sample, centers corresponding to the PL of bismuth D0Xs within both the high density region and the lower concentration diffused tail of the implanted donor profile are identifiable

When is a polymorph not a polymorph? Helical trimeric O-H···O synthons in trans-1,4-diethynylcyclohexane-1,4-diol

Two polymorphs (A and B) of trans-1,4-diethynylcyclohexane-1,4-diol represent a unique example of the simultaneous occurrence of both conformational polymorphism and conformational isomorphism, while a pseudopolymorphic monohydrate is closely related

Crystal engineering urea organic acid hydrogen bonded networks with solvent inclusion properties

Eleven structurally similar materials based on hydrogen bonded networks of N-phenylurea and 5-nitroisophthalic acid have been engineered where nine have interesting solvent inclusion and guest release properties.</p

Single versus dual antiplatelet therapy following peripheral arterial endovascular intervention for chronic limb threatening ischaemia:retrospective cohort study

ObjectivesAntiplatelet therapy following peripheral arterial endovascular intervention lacks high quality evidence to guide practice. The aim of this study was to assess the effect of three months of dual antiplatelet therapy on amputation-free survival following peripheral arterial endovascular intervention in patients with chronic limb threatening ischemia.MethodsA retrospective review of symptomatic patients undergoing primary peripheral arterial endovascular intervention over a seven-year period was performed. The primary outcome measure was amputation-free survival. A sample size calculation based on previous cohort studies suggested that 629 limbs would be required to show a difference between single and dual therapy. Kaplan-Meier estimates and multivariate logistic regression analysis of recorded baseline characteristics was performed to determine predictors of amputation-free survival. Dual antiplatelet therapy was routinely given for 3 months.Results754 limbs were treated with primary angioplasty and/or stenting over a 7-year period, 508 of these for chronic limb threatening ischemia. There was no difference in unadjusted amputation-free survival between patients with chronic limb threatening ischaemia taking single vs. dual antiplatelet therapy (69% vs. 74% respectively Log rank Chi2 = 0.1, p = .72). After adjusting for confounders, at 1 year there was also no significant difference in amputation-free survival between patients taking single vs. dual antiplatelet therapy [OR 0.8, 95% CI 0.5-1.2, p = .3]. There was no difference in rates of major bleeding between single and dual antiplatelet therapy.ConclusionsThere was no clear evidence of reduced amputation-free survival in patients with chronic limb threatening ischemia undergoing peripheral arterial endovascular intervention being treated with dual antiplatelet therapy for 3 months. This is at odds with other retrospective case series and highlights the limitations in basing clinical practice on such data. There is a need for an adequately powered, independent randomised trial to definitively answer the question

Transforming ophthalmic education into virtual learning during COVID-19 pandemic : a global perspective

Objective: The coronavirus disease 2019 (COVID-19) pandemic has imposed measures of social distancing and barriers in delivery of "in person" education. Institutions, involved in training the next generation of ophthalmologists, are using alternative teaching methods to maintain the standard of education. Methods: We conducted a worldwide survey among physicians, who are actively involved in Ophthalmology-related education, between 3 and 14 April 2020. The expert survey, developed on the basis of literature search and focus group discussions, comprised 23 questions addressing the use of e-learning in Ophthalmology during the COVID-19 pandemic. Results: A total of 321 participants from both academic and non-academic institutions worldwide, with variable practice experience and expertise, completed the survey. Before the pandemic, the majority of participants used traditional training modalities, including lectures, grand rounds and journal clubs, and 48% did not use any e-learning. There was a statistically significant increase in the use of all e-learning alternatives during the pandemic (p &lt; 0.001), associated mainly with the availability of e-learning facilities (p &lt; 0.001) and the academic character of institutions (p &lt; 0.001). Zoom\uae was recognized as the mostly used platform for virtual teaching. Although theoretical teaching may take place, the surgical training of residents/fellows was dramatically reduced. The latter was significantly associated with participants' perspectives about teaching practices (p &lt; 0.001). Conclusion: COVID-19 pandemic imposed great challenges in the educational field of Ophthalmology. The experience related to virtual training in Ophthalmology, gained during the pandemic, may change the traditional teaching practices in the world and provide new educational opportunities