Five really easy steps to build a homemade low-cost simulator

AIM: The aim of this study was to evaluate how simple it is to build a homemade low-cost simulator using a simple 5-step scheme. METHODS: A scheme explaining how to build an endoscopic surgery simulator in 5 easy steps was presented to 26 surgeons. The simulator required a pair of scissors and easy-to-find materials. Its total cost was less than €35. The participants assessed the simulator using common endoscopic training toys or ex vivo tissue and completed an anonymous query comparing it with other commercial simulators that they had experienced before. RESULTS: In all, 84.6% found the simulator really easy to build. Every participant felt that he or she could do the same simulator themselves. Comparing with other commercial available box simulators, the majority of participants found the homemade simulator easier to (a) mount and dismount, (b) transport, (c) clean, and (d) use when practicing alone. CONCLUSIONS: Anyone can build its own simulator for a small amount of money

On the perturbative S-matrix of generalized sine-Gordon models

Motivated by its relation to the Pohlmeyer reduction of AdS_5 x S^5 superstring theory we continue the investigation of the generalized sine-Gordon model defined by SO(N+1)/SO(N) gauged WZW theory with an integrable potential. Extending our previous work (arXiv:0912.2958) we compute the one-loop two-particle S-matrix for the elementary massive excitations. In the N = 2 case corresponding to the complex sine-Gordon theory it agrees with the charge-one sector of the quantum soliton S-matrix proposed in hep-th/9410140. In the case of N > 2 when the gauge group SO(N) is non-abelian we find a curious anomaly in the Yang-Baxter equation which we interpret as a gauge artifact related to the fact that the scattered particles are not singlets under the residual global subgroup of the gauge group

Classical and Quantum Solitons in the Symmetric Space Sine-Gordon Theories

We construct the soliton solutions in the symmetric space sine-Gordon theories. The latter are a series of integrable field theories in 1+1-dimensions which are associated to a symmetric space F/G, and are related via the Pohlmeyer reduction to theories of strings moving on symmetric spaces. We show that the solitons are kinks that carry an internal moduli space that can be identified with a particular co-adjoint orbit of the unbroken subgroup H of G. Classically the solitons come in a continuous spectrum which encompasses the perturbative fluctuations of the theory as the kink charge becomes small. We show that the solitons can be quantized by allowing the collective coordinates to be time-dependent to yield a form of quantum mechanics on the co-adjoint orbit. The quantum states correspond to symmetric tensor representations of the symmetry group H and have the interpretation of a fuzzy geometric version of the co-adjoint orbit. The quantized finite tower of soliton states includes the perturbative modes at the base.Comment: 53 pages, additional comments and small errors corrected, final journal versio

Exploring the canonical behaviour of long gamma-ray bursts using an intrinsic multiwavelength afterglow correlation

In this paper, we further investigate the relationship, reported by Oates et al., between the optical/UV afterglow luminosity (measured at restframe 200 s) and average afterglow decay rate (measured from restframe 200 s onwards) of long duration gamma-ray bursts (GRBs). We extend the analysis by examining the X-ray light curves, finding a consistent correlation. We therefore explore how the parameters of these correlations relate to the prompt emission phase and, using a Monte Carlo simulation, explore whether these correlations are consistent with predictions of the standard afterglow model. We find significant correlations between: log  LO, 200 s and log  LX, 200 s; αO, >200 s and αX, >200 s, consistent with simulations. The model also predicts relationships between log Eiso and log  L200 s; however, while we find such relationships in the observed sample, the slope of the linear regression is shallower than that simulated and inconsistent at ≳3σ. Simulations also do not agree with correlations observed between log  L200 s and α> 200 s, or logEiso logEiso and α> 200 s. Overall, these observed correlations are consistent with a common underlying physical mechanism producing GRBs and their afterglows regardless of their detailed temporal behaviour. However, a basic afterglow model has difficulty explaining all the observed correlations. This leads us to briefly discuss alternative more complex models

Exploring the canonical behaviour of long gamma-ray bursts with an intrinsic multiwavelength afterglow correlation

In this conference proceeding we examine a correlation between the afterglow luminosity (measured at restframe 200 s; logL200s) and average afterglow decay rate (measured from restframe 200 s onwards; α>200s) found in both the optical/UV and X-ray afterglows of long duration Gamma-ray Bursts (GRBs). Examining the X-ray light curves, we find the correlation does not depend on the presence of specific light curve features. We explore how the parameters in the optical/UV and X-ray bands relate to each other and to the prompt emission phase. We also use a Monte Carlo simulation to explore whether these relationships are consistent with predictions of the standard afterglow model. We conclude that the correlations are consistent with a common underlying physical mechanism producing GRBs and their afterglows regardless of their detailed temporal behaviour. However, a basic afterglow model has difficulty explaining correlations involving α>200s. We therefore briefly discuss alternative more complex models

Entanglement Content of Quantum Particle Excitations I. Free Field Theory

We evaluate the entanglement entropy of a single connected region in excited states of one-dimensional massive free theories with finite numbers of particles, in the limit of large volume and region length. For this purpose, we use finite-volume form factor expansions of branch-point twist field two-point functions. We find that the additive contribution to the entanglement due to the presence of particles has a simple "qubit" interpretation, and is largely independent of momenta: it only depends on the numbers of groups of particles with equal momenta. We conjecture that at large momenta, the same result holds for any volume and region lengths, including at small scales. We provide accurate numerical verifications

Use of archival versus newly collected tumor samples for assessing PD-L1 expression and overall survival : an updated analysis of KEYNOTE-010 trial

Background: In KEYNOTE-010, pembrolizumab versus docetaxel improved overall survival (OS) in patients with programmed death-1 protein (PD)-L1-positive advanced non-small-cell lung cancer (NSCLC). A prespecified exploratory analysis compared outcomes in patients based on PD-L1 expression in archival versus newly collected tumor samples using recently updated survival data. Patients and methods: PD-L1 was assessed centrally by immunohistochemistry (22C3 antibody) in archival or newly collected tumor samples. Patients received pembrolizumab 2 or 10 mg/kg Q3W or docetaxel 75 mg/m2 Q3W for 24 months or until progression/intolerable toxicity/other reason. Response was assessed by RECIST v1.1 every 9 weeks, survival every 2 months. Primary end points were OS and progression-free survival (PFS) in tumor proportion score (TPS) 50% and 1%; pembrolizumab doses were pooled in this analysis. Results: At date cut-off of 24 March 2017, median follow-up was 31 months (range 23-41) representing 18 additional months of follow-up from the primary analysis. Pembrolizumab versus docetaxel continued to improve OS in patients with previously treated, PD-L1-expressing advanced NSCLC; hazard ratio (HR) was 0.66 [95% confidence interval (CI): 0.57, 0.77]. Of 1033 patients analyzed, 455(44%) were enrolled based on archival samples and 578 (56%) on newly collected tumor samples. Approximately 40% of archival samples and 45% of newly collected tumor samples were PD-L1 TPS 50%. For TPS 50%, the OS HRs were 0.64 (95% CI: 0.45, 0.91) and 0.40 (95% CI: 0.28, 0.56) for archival and newly collected samples, respectively. In patients with TPS 1%, OS HRs were 0.74 (95% CI: 0.59, 0.93) and 0.59 (95% CI: 0.48, 0.73) for archival and newly collected samples, respectively. In TPS 50%, PFS HRs were similar across archival [0.63 (95% CI: 0.45, 0.89)] and newly collected samples [0.53 (95% CI: 0.38, 0.72)]. In patients with TPS 1%, PFS HRs were similar across archival [0.82 (95% CI: 0.66, 1.02)] and newly collected samples [0.83 (95% CI: 0.68, 1.02)]. Conclusion: Pembrolizumab continued to improve OS over docetaxel in intention to treat population and in subsets of patients with newly collected and archival samples

Economic History and History of Economics: Complementary Approaches to Portuguese Economic Development

This chapter focuses on how the problems of economic development were addressed by the Portuguese historiography of the late nineteenth and twentieth centuries. The ensuing discussion benefits from the simultaneous consideration of two historiographical domains that complement each other: economic history and the history of economics. On the one hand, there are the authors and texts of economic history that seek to describe the facts and circumstances related to the functioning and dynamics of economic reality, for a given period or succession of periods, in order to establish evolutionary trends. On the other hand, there are the authors and texts of the history of economics that seek to adopt analytical forms (principles and laws) and doctrinal and programmatic frameworks (visions and ideologies) aimed at providing explanatory meaning to the observed economic changes, phenomena and regularities. A true understanding of the important issues pertaining to Portuguese economic development is to be found, however, in the intersection of these distinct but complementary historiographical perspectives.info:eu-repo/semantics/publishedVersio

Substrate-induced band gap opening in epitaxial graphene

Graphene has shown great application potentials as the host material for next generation electronic devices. However, despite its intriguing properties, one of the biggest hurdles for graphene to be useful as an electronic material is its lacking of an energy gap in the electronic spectra. This, for example, prevents the use of graphene in making transistors. Although several proposals have been made to open a gap in graphene's electronic spectra, they all require complex engineering of the graphene layer. Here we show that when graphene is epitaxially grown on the SiC substrate, a gap of ~ 0.26 is produced. This gap decreases as the sample thickness increases and eventually approaches zero when the number of layers exceeds four. We propose that the origin of this gap is the breaking of sublattice symmetry owing to the graphene-substrate interaction. We believe our results highlight a promising direction for band gap engineering of graphene.Comment: 10 pages, 4 figures; updated reference