The braided Ptolemy-Thompson group is finitely presented

Pursueing our investigations on the relations between Thompson groups and mapping class groups, we introduce the group $T^*$ (and its further generalizations) which is an extension of the Ptolemy-Thompson group $T$ by means of the full braid group $B_{\infty}$ on infinitely many strands. We prove that it is a finitely presented group with solvable word problem, and give an explicit presentation of it.Comment: 35

Electroquasistatic sensors for surface and subsurface nano-imaging of integrated circuit features

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2010.Includes bibliographical references (p. 137-138).The following thesis relates to the design, simulation, and testing of electroquasistatic (EQS) sensors to be used for feature/defect location and imaging. The aim of this thesis is to launch an investigation into the use of EQS sensor arrays for non-destructive evaluation and quality control purposes for integrated circuit industry applications. Research into three specific areas serves as the primary focus of the thesis: 1.) The use of EQS sensors to penetrate the surface of doped silicon and locate p-n junctions and doped wells. Arrays of coplanar EQS sensors are scanned laterally over the surface of a doped silicon bulk at a fixed scan height. Electric fields from the driven EQS sensor array are capable of penetrating the surface of the semiconductor when sensors are operated at a frequency comparable to its charge relaxation break frequency. It is demonstrated through finite element method (FEM) simulations that voltage-driven EQS electrodes can couple into the p-n junction without making any direct electrical contact with the semiconducting bulk. A new methodology for locating p-n junctions is presented where the currents on these voltage-driven sensors are monitored for harmonic distortion due to the junction's nonlinear drift/diffusion carrier dynamics. With sensors located over a p-n junction at a scan height of 200 nm and driven at 1GHz, the ratio of the second harmonic current to the fundamental current on a sensor is shown to exceed 9%. Such an IC imaging technique could prove to be useful for verification and detection of fabrication errors, externally monitoring current flows, as well as detecting hidden Trojan circuits that might be present. 2.) The use of EQS sensors to locate and image surface features and contaminant objects on photomasks. Motivation for research into this area comes from the desire to be able to locate and remove contaminant particles that might be present on extreme ultraviolet lithography (EUVL) photomasks used in the mass production of next-generation integrated circuits. FEM simulation results demonstrate the sensitivity of EQS sensor arrays in detecting various contaminant particles located in a 100nm wide by 70nm deep gap in the absorber layer of an EUVL photomask. A millimeter-scale, in-lab experiment using capacitive sensors is performed with sensors and materials having similar aspect ratios and electrical properties to those simulated. Experiments demonstrate both the capabilities and limitations of sensors in detecting various objects located in a trenches milled out of aluminum. Additionally, a discussion of the need for low-noise pickup circuitry to interface with sensors is presented. 3.) An investigation into the inversion of sensor transimpedance response signals into predicted feature/defect profiles. In this case study, an inverse electromagnetic sensor problem is solved by training a radial basis function artificial neural network (RBF-ANN) to accurately approximate the forward mapping of the physical dimensions (width and depth) of a high aspect ratio trench in doped silicon into a sensor's transimpedance response as the sensor array scans past the trench at a fixed scan height. This is an example of the type of inverse problem that might be encountered in an EQS array microscope and one possible approach to its solution. The function-approximation network is then inserted into an iterative signal inversion routine which converges to a prediction for the trench's dimensions, given a measured transimpedance response. The routine is capable of predicting trench dimensions to within 1% of their actual value. In all three cases, research involves extensive finite element method (FEM) simulations of sensor performance using COMSOL Multiphysics.by Benjamin L. Cannon.S.M

Nine years of comparative effectiveness research education and training: initiative supported by the PhRMA Foundation

The term comparative effectiveness research (CER) took center stage with passage of the American Recovery and Reinvestment Act (2009). The companion US$1.1 billion in funding prompted the launch of initiatives to train the scientific workforce capable of conducting and using CER. Passage of the Patient Protection and Affordable Care Act (2010) focused these initiatives on patients, coining the term ‘patient-centered outcomes research’ (PCOR). Educational and training initiatives were soon launched. This report describes the initiative of the Pharmaceutical Research and Manufacturers Association of America (PhRMA) Foundation. Through provision of grant funding to six academic Centers of Excellence, to spearheading and sponsoring three national conferences, the PhRMA Foundation has made significant contributions to creation of the scientific workforce that conducts and uses CER/PCOR

Automated mask creation from a 3D model using Faethm.

We have developed and implemented a method which given a three-dimensional object can infer from topology the two-dimensional masks needed to produce that object with surface micro-machining. The masks produced by this design tool can be generic, process independent masks, or if given process constraints, specific for a target process. This design tool calculates the two-dimensional mask set required to produce a given three-dimensional model by investigating the vertical topology of the model

The comparative safety and effectiveness of bivalirudin versus heparin monotherapy in patients on dialysis undergoing percutaneous coronary intervention: Insights from the Blue Cross Blue Shield of Michigan cardiovascular consortium

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/139064/1/ccd27001.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/139064/2/ccd27001_am.pd

An infinite genus mapping class group and stable cohomology

We exhibit a finitely generated group \M whose rational homology is isomorphic to the rational stable homology of the mapping class group. It is defined as a mapping class group associated to a surface \su of infinite genus, and contains all the pure mapping class groups of compact surfaces of genus $g$ with $n$ boundary components, for any $g\geq 0$ and $n>0$. We construct a representation of \M into the restricted symplectic group ${\rm Sp_{res}}({\cal H}_r)$ of the real Hilbert space generated by the homology classes of non-separating circles on \su, which generalizes the classical symplectic representation of the mapping class groups. Moreover, we show that the first universal Chern class in H^2(\M,\Z) is the pull-back of the Pressley-Segal class on the restricted linear group ${\rm GL_{res}}({\cal H})$ via the inclusion ${\rm Sp_{res}}({\cal H}_r)\subset {\rm GL_{res}}({\cal H})$.Comment: 14p., 8 figures, to appear in Commun.Math.Phy

State transitions across the Strep A disease spectrum: scoping review and evidence gaps.

The spectrum of diseases caused by Streptococcus pyogenes (Strep A) ranges from superficial to serious life-threatening invasive infections. We conducted a scoping review of published articles between 1980 and 2021 to synthesize evidence of state transitions across the Strep A disease spectrum. We identified 175 articles reporting 262 distinct observations of Strep A disease state transitions. Among the included articles, the transition from an invasive or toxin-mediated disease state to another disease state (i.e., to recurrent ARF, RHD or death) was described 115 times (43.9% of all included transition pairs) while the transition to and from locally invasive category was the lowest (n = 7; 0.02%). Transitions from well to any other state was most frequently reported (49%) whereas a relatively higher number of studies (n = 71) reported transition from invasive disease to death. Transitions from any disease state to locally invasive, Strep A pharyngitis to invasive disease, and chronic kidney disease to death were lacking. Transitions related to severe invasive diseases were more frequently reported than superficial ones. Most evidence originated from high-income countries and there is a critical need for new studies in low- and middle-income countries to infer the state transitions across the Strep A disease spectrum in these high-burden settings

Randomized Comparison of Everolimus- and Paclitaxel-Eluting Stents 2-Year Follow-Up From the SPIRIT (Clinical Evaluation of the XIENCE V Everolimus Eluting Coronary Stent System) IV Trial

ObjectivesWe sought to determine whether the differences in outcomes present between everolimus-eluting stents (EES) and paclitaxel-eluting stents (PES) in the SPIRIT (Clinical Evaluation of the XIENCE V Everolimus Eluting Coronary Stent System) IV trial at 1 year were sustained with longer-term follow-up.BackgroundIn the SPIRIT IV trial, patients undergoing percutaneous coronary intervention who were randomized to EES compared with PES experienced lower 1-year rates of target lesion failure (cardiac death, target vessel myocardial infarction [MI], or ischemia-driven target lesion revascularization [TLR]), with significant reductions in the individual rates of MI, TLR, and stent thrombosis.MethodsWe prospectively randomized 3,687 patients with up to 3 noncomplex previously untreated native coronary artery lesions to EES versus PES at 66 U.S. sites. Follow-up through 2 years is complete in 3,578 patents (97.0%).ResultsTreatment with EES compared with PES reduced the 2-year rates of TLF (6.9% vs. 9.9%, p = 0.003), all MI (2.5% vs. 3.9%, p = 0.02), Q-wave MI (0.1% vs. 0.8%, p = 0.002), stent thrombosis (0.4% vs. 1.2%, p = 0.008), and ischemia-driven TLR (4.5% vs. 6.9%, p = 0.004), with nonsignificantly different rates of all-cause and cardiac mortality. Between 1 year and 2 years, there were no significant differences in adverse event rates between the 2 stent types.ConclusionsIn the large-scale, prospective, multicenter, randomized SPIRIT IV trial, the benefits of EES compared with those of PES present at 1 year were sustained at 2 years. (Clinical Evaluation of the XIENCE V Everolimus Eluting Coronary Stent System; NCT01016041