Entanglement cost of generalised measurements

Bipartite entanglement is one of the fundamental quantifiable resources of quantum information theory. We propose a new application of this resource to the theory of quantum measurements. According to Naimark's theorem any rank 1 generalised measurement (POVM) M may be represented as a von Neumann measurement in an extended (tensor product) space of the system plus ancilla. By considering a suitable average of the entanglements of these measurement directions and minimising over all Naimark extensions, we define a notion of entanglement cost E_min(M) of M. We give a constructive means of characterising all Naimark extensions of a given POVM. We identify various classes of POVMs with zero and non-zero cost and explicitly characterise all POVMs in 2 dimensions having zero cost. We prove a constant upper bound on the entanglement cost of any POVM in any dimension. Hence the asymptotic entanglement cost (i.e. the large n limit of the cost of n applications of M, divided by n) is zero for all POVMs. The trine measurement is defined by three rank 1 elements, with directions symmetrically placed around a great circle on the Bloch sphere. We give an analytic expression for its entanglement cost. Defining a normalised cost of any d-dimensional POVM by E_min(M)/log(d), we show (using a combination of analytic and numerical techniques) that the trine measurement is more costly than any other POVM with d>2, or with d=2 and ancilla dimension 2. This strongly suggests that the trine measurement is the most costly of all POVMs.Comment: 20 pages, plain late

Intraoperative changes in blood coagulation and thrombelastographic monitoring in liver transplantation

The blood coagulation system of 66 consecutive patients undergoing consecutive liver transplantations was monitored by thrombelastograph and analytic coagulation profile. A poor preoperative coagulation state, decrease in levels of coagulation factors, progressive fibrinolysis, and whole blood clot lysis were observed during the preanhepatic and anhepatic stages of surgery. A further general decrease in coagulation factors and platelets, activation of fibrinolysis, and abrupt decrease in levels of factors V and VIII occurred before and with reperfusion of the homograft. Recovery of blood coagulability began 30-60 min after reperfusion of the graft liver, and coagulability had returned toward baseline values 2 hr after reperfusion. A positive correlation was shown between the variables of thrombelastography and those of the coagulation profile. Thrombelastography was shown to be a reliable and rapid monitoring system. Its use was associated with a 33% reduction of blood and fluid infusion volume, whereas blood coagulability was maintained without an increase in the number of blood product donors

Group Leaders Optimization Algorithm

We present a new global optimization algorithm in which the influence of the leaders in social groups is used as an inspiration for the evolutionary technique which is designed into a group architecture. To demonstrate the efficiency of the method, a standard suite of single and multidimensional optimization functions along with the energies and the geometric structures of Lennard-Jones clusters are given as well as the application of the algorithm on quantum circuit design problems. We show that as an improvement over previous methods, the algorithm scales as N^2.5 for the Lennard-Jones clusters of N-particles. In addition, an efficient circuit design is shown for two qubit Grover search algorithm which is a quantum algorithm providing quadratic speed-up over the classical counterpart

Plate-impact loading of cellular structures formed by selective laser melting

Studies of the shock loading of porous material have the potential to improve our understanding of factors such as density, crush strength and pore size on energy absorbing capability. Porous components were manufactured using Selective Laser Melting (SLM) in which layers of metal powder are fused together to create a structure specified by an electronic file. Samples have been manufactured in which a lattice is formed by an array of intersecting rods angled at 45 degrees to the surface of a 6 mm thick x ~100 mm diameter disc. The cell size is 1 mm3 and the density is 44.6% of solid. A 100 mm gas gun has been used to impact the porous samples onto solid stainless steel plates. Het-V laser interferometry was used to measure the velocity vs. time profile of the transmitted shock. The experimental results were compared with three dimensional computer predictions. It was found that the simulations reproduced the main features of the experimental record but tended to underestimate the measured velocities, suggesting that the codes were not calculating the energy absorbed by the lattice correctly. Additional calculations were performed with the aim of building a picture of the processes of energy absorption in cellular materials whose structure is varied systematically. These supporting studies suggest a possible explanation for the observed computational/experimental discrepancies. © 2012 British Crown

Metatarsophalangeal joint function during sprinting: A comparison of barefoot and sprint spike shod foot conditions

This is the authors' post print as accepted for publication in Journal of Applied Biomechanics. The published version is available at http://journals.humankinetics.com/jabThe metatarsophalangeal joint is an important contributor to lower limb energetics during sprint running. This study compared the kinematics, kinetics and energetics of the metatarsophalangeal joint during sprinting barefoot and wearing standardised sprint spikes. The aim of this investigation was to determine whether standard sprinting footwear alters the natural motion and function of the metatatarsophalangeal joint exhibited during barefoot sprint running. Eight trained sprinters performed maximal sprints along a runway, four sprints in each condition. Three dimensional high speed (1000 Hz) kinematic and kinetic data were collected at the 20 m point. Joint angle, angular velocity, moment, power and energy were calculated for the metatarsophalangeal joint. Sprint spikes significantly increase sprinting velocity (0.3 m/s average increase), yet limit the range of motion about the metatarsophalangeal joint (17.9 % average reduction) and reduce peak dorsiflexion velocity (25.5 % average reduction), thus exhibiting a controlling affect over the natural behaviour of the foot. However, sprint spikes improve metatarsophalangeal joint kinetics by significantly increasing the peak metatarsophalangeal joint moment (15 % average increase) and total energy generated during the important push-off phase (0.5 J to 1.4 J). The results demonstrate substantial changes in metatarsophalangeal function and potential improvements in performance-related parameters due to footwear

Genomic diversity of Helicobacter pylori populations from different regions of the human stomach

Individuals infected with Helicobacter pylori harbor unique and diverse populations of quasispecies, but diversity between and within different regions of the human stomach and the process of bacterial adaptation to each location are not yet well understood. We applied whole-genome deep sequencing to characterize the within- and between-stomach region genetic diversity of H. pylori populations from paired antrum and corpus biopsies of 15 patients, along with single biopsies from one region of an additional 3 patients, by scanning allelic diversity. We combined population deep sequencing with more conventional sequencing of multiple H. pylori single colony isolates from individual biopsies to generate a unique dataset. Single colony isolates were used to validate the scanning allelic diversity pipelines. We detected extensive population allelic diversity within the different regions of each patient’s stomach. Diversity was most commonly found within non-coding, hypothetical, outer membrane, restriction modification system, virulence, lipopolysaccharide biosynthesis, efflux systems, and chemotaxis-associated genes. Antrum and corpus populations from the same patient grouped together phylogenetically, indicating that most patients were initially infected with a single strain, which then diversified. Single colonies from the antrum and corpus of the same patients grouped into distinct clades, suggesting mechanisms for within-location adaptation across multiple H. pylori isolates from different patients. The comparisons made available by combined sequencing and analysis of isolates and populations enabled comprehensive analysis of the genetic changes associated with H. pylori diversification and stomach region adaptation

Power-law rheology in the bulk and at the interface: quasi-properties and fractional constitutive equations

Consumer products, such as foods, contain numerous polymeric and particulate additives that play critical roles in maintaining their stability, quality and function. The resulting materials exhibit complex bulk and interfacial rheological responses, and often display a distinctive power-law response under standard rheometric deformations. These power laws are not conveniently described using conventional rheological models, without the introduction of a large number of relaxation modes. We present a constitutive framework using fractional derivatives to model the power-law responses often observed experimentally. We first revisit the concept of quasi-properties and their connection to the fractional Maxwell model (FMM). Using Scott-Blair's original data, we demonstrate the ability of the FMM to capture the power-law response of ‘highly anomalous’ materials. We extend the FMM to describe the viscoelastic interfaces formed by bovine serum albumin and solutions of a common food stabilizer, Acacia gum. Fractional calculus allows us to model and compactly describe the measured frequency response of these interfaces in terms of their quasi-properties. Finally, we demonstrate the predictive ability of the FMM to quantitatively capture the behaviour of complex viscoelastic interfaces by combining the measured quasi-properties with the equation of motion for a complex fluid interface to describe the damped inertio-elastic oscillations that are observed experimentally.United States. National Aeronautics and Space Administration (Microgravity Fluid Sciences (Code UG) for support of this research under grant no. NNX09AV99G

Risk of Cerebrovascular Events in 178 962 Five-Year Survivors of Cancer Diagnosed at 15 to 39 Years of Age: The TYACSS (Teenage and Young Adult Cancer Survivor Study)

Background: Survivors of teenage and young adult (TYA) cancer are at risk of cerebrovascular events, but the magnitude of and extent to which this risk varies by cancer type, decade of diagnosis, age at diagnosis and attained age remains uncertain. This is the largest ever cohort study to evaluate the risks of hospitalisation for a cerebrovascular event among long-term survivors of TYA cancer. Methods:The population-based Teenage and Young Adult Cancer Survivor Study (N=178,962) was linked to Hospital Episode Statistics data for England to investigate the risks of hospitalisation for a cerebrovascular event among 5-year survivors of cancer diagnosed when aged 15-39 years. Observed numbers of first hospitalisations for cerebrovascular events were compared to that expected from the general population using standardised hospitalisation ratios (SHR) and absolute excess risks (AER) per 10,000 person-years. Cumulative incidence was calculated with death considered a competing risk. Results: Overall, 2,782 cancer survivors were hospitalised for a cerebrovascular event—40% higher than expected (SHR=1.4, 95% confidence interval [CI]=1.3-1.4). Survivors of central nervous system (CNS) tumours (SHR=4.6, CI=4.3-5.0), head & neck tumours (SHR=2.6, CI=2.2-3.1) and leukaemia (SHR=2.5, CI=1.9-3.1) were at greatest risk. Males had a significantly higher AER than females (AER=7 versus 3), especially among head & neck tumour survivors (AER=30 versus 11). By age 60, 9%, 6% and 5% of CNS tumour, head & neck tumour, and leukaemia survivors, respectively, had been hospitalised for a cerebrovascular event. Beyond age 60, every year 0.4% of CNS tumour survivors were hospitalised for a cerebral infarction (versus 0.1% expected. Whereas at any age, every year 0.2% of head & neck tumour survivors were hospitalised for a cerebral infarction 7 (versus 0.06% expected). Conclusions: Survivors of a CNS tumour, head & neck tumour, and leukaemia are particularly at risk of hospitalisation for a cerebrovascular event. The excess risk of cerebral infarction among CNS tumour survivors increases with attained age. For head & neck tumour survivors this excess risk remains high across all ages. These groups of survivors, and in particular males, should be considered for surveillance of cerebrovascular risk factors and potential pharmacological interventions for cerebral infarction prevention

A single fungal strain was the unexpected cause of a mass aspergillosis outbreak in the world's largest and only flightless parrot.

Kākāpō are a critically endangered species of parrots restricted to a few islands off the coast of New Zealand. Kākāpō are very closely monitored, especially during nesting seasons. In 2019, during a highly successful nesting season, an outbreak of aspergillosis affected 21 individuals and led to the deaths of 9, leaving a population of only 211 kākāpō. In monitoring this outbreak, cultures of aspergillus were grown, and genome sequenced. These sequences demonstrate that, very unusually for an aspergillus outbreak, a single strain of aspergillus caused the outbreak. This strain was found on two islands, but only one had an outbreak of aspergillosis; indicating that the strain was necessary, but not sufficient, to cause disease. Our analysis provides an understanding of the 2019 outbreak and provides potential ways to manage such events in the future