Design of a Scalable Path Service for the Internet

Despite the world-changing success of the Internet, shortcomings in its routing and forwarding system have become increasingly apparent. One symptom is an escalating tension between users and providers over the control of routing and forwarding of packets: providers understandably want to control use of their infrastructure, and users understandably want paths with sufficient quality-of-service (QoS) to improve the performance of their applications. As a result, users resort to various “hacks” such as sending traffic through intermediate end-systems, and the providers fight back with mechanisms to inspect and block such traffic. To enable users and providers to jointly control routing and forwarding policies, recent research has considered various architectural approaches in which provider- level route determination occurs separately from forwarding. With this separation, provider-level path computation and selection can be provided as a centralized service: users (or their applications) send path queries to a path service to obtain provider- level paths that meet their application-specific QoS requirements. At the same time, providers can control the use of their infrastructure by dictating how packets are forwarded across their network. The separation of routing and forwarding offers many advantages, but also brings a number of challenges such as scalability. In particular, the path service must respond to path queries in a timely manner and periodically collect topology information containing load-dependent (i.e., performance) routing information. We present a new design for a path service that makes use of expensive pre- computations, parallel on-demand computations on performance information, and caching of recently computed paths to achieve scalability. We demonstrate that, us- ing commodity hardware with a modest amount of resources, the path service can respond to path queries with acceptable latency under a realistic workload. The ser- vice can scale to arbitrarily large topologies through parallelism. Finally, we describe how to utilize the path service in the current Internet with existing Internet applica- tions

Anti-fungal bandages containing cinnamon extract

© 2019 The Authors. International Wound Journal published by Medicalhelplines.com Inc and John Wiley & Sons Ltd.Cinnamon-containing polycaprolactone (PCL) bandages were produced by pressurised gyration and their anti-fungal activities against Candida albicans were investigated. It was found that by preparing and spinning polymer solutions of cinnamon with PCL, fibres capable of inhibiting fungal growth could be produced, as observed in disk diffusion tests for anti-fungal susceptibility. Fascinatingly, compared with raw cinnamon powder, the novel cinnamon-loaded fibres had outstanding long-term activity. The results presented here are very promising and may indeed accelerate a new era of using completely natural materials in biomedical applications, especially in wound healing.Peer reviewe

Heisenberg Uncertainty Principle as Probe of Entanglement Entropy: Application to Superradiant Quantum Phase Transitions

Quantum phase transitions are often embodied by the critical behavior of purely quantum quantities such as entanglement or quantum fluctuations. In critical regions, we underline a general scaling relation between the entanglement entropy and one of the most fundamental and simplest measure of the quantum fluctuations, the Heisenberg uncertainty principle. Then, we show that the latter represents a sensitive probe of superradiant quantum phase transitions in standard models of photons such as the Dicke Hamiltonian, which embodies an ensemble of two-level systems interacting with one quadrature of a single and uniform bosonic field. We derive exact results in the thermodynamic limit and for a finite number N of two-level systems: as a reminiscence of the entanglement properties between light and the two-level systems, the product $\Delta x\Delta p$ diverges at the quantum critical point as $N^{1/6}$. We generalize our results to the double quadrature Dicke model where the two quadratures of the bosonic field are now coupled to two independent sets of two level systems. Our findings, which show that the entanglement properties between light and matter can be accessed through the Heisenberg uncertainty principle, can be tested using Bose-Einstein condensates in optical cavities and circuit quantum electrodynamicsComment: 7 pages, 3 figures. Published Versio

Türkiye'de pamuk yetiştiriciliğinin enerji bilançosu ve sera gazı emisyonlarının belirlenmesi: Diyarbakır İli Bismil İlçesi Örneği]

In this study, the energy balance and Greenhouse Gas Emissions (GHG) of cotton cultivation in Bismil district of Diyarbakır province in Turkey was defined. The energy balance and GHG of cotton cultivation was computed by conducting face to face surveys with 73 farms in the 2018-2019 cultivation season, which were selected by simple random sampling method. The energy input and output in cotton cultivation were computed as 54 617.62 MJ ha-1 and 65 984.42 MJ ha-1, respectively. Energy inputs occurs of electricity energy with 18 608.40 MJ ha-1 (34.06%), chemical fertilizers energy with 15 254.67 MJ ha-1 (27.93%), diesel fuel energy with 14 364.68 (26.30%), irrigation water energy with 3 559.50 MJ ha-1 (6.53%), machinery energy with 1 152.79 MJ ha-1 (2.11%), chemicals energy with 1 075.76 MJ ha-1 (1.96%), seed energy with 307.98 MJ ha-1 (0.57%), human labour energy with 293.84 MJ ha-1 (0.54%), respectively. Total energy inputs in cotton cultivation can be classified as 67.43% direct, 32.57% indirect, 7.62% renewable and 92.38% non-renewable. Energy use efficiency, specific energy, energy productivity and net energy in cotton cultivation were computed as 1.21, 9.77 MJ kg-1, 0.10 kg MJ-1 and 11 366.80 MJ ha-1, respectively. Total GHG emissions were computed as 6 482.36 kgCO2-eqha-1 for cotton cultivation with the greatest input part for electricity with 47.94% (3 107.60 kgCO2-eqha-1). The electricity followed up nitrogen with 16.29% (1 055.67 kgCO2-eqha-1), irrigation water with 14.82% (960.50 kgCO2-eqha-1), diesel fuel with 10.86% (704.08 kgCO2-eqha-1), seed with 3.07% (199.14 kgCO2-eqha-1 ), chemicals with 2.28% (147.76 kgCO2-eqha-1), phosphorous with 1.78% (115.64 kgCO2-eqha-1), human labour with 1.62% (104.94 kgCO2-eqha-1), machinery with 1.26% (81.85 kgCO2-eqha-1) and potassium with 0.08% (5.18 kgCO2-eqha-1), respectively. Additionally, GHG ratio value was computed as 1.16 kgCO2-eqkg-1 in cotton cultivation. © 2021 Namik Kemal University - Agricultural Faculty. All rights reserved.We would like to thank the cotton producers who supported us in the survey

1/f noise in hydrogenated amorphous silicon-germanium alloys

Measurements were made of conductance noise of a-Si:H and a-Si 1-xGex:H in two different geometries: one where the current flow is transverse to the surface and the other where it is longitudinal to the surface. Because of the large change in sample resistance between the two geometries, it was not possible to measure both geometries at the same temperature. For both geometries, alloyinzg with up to 40% Ge reduces the noise magnitude by several orders of magnitude over that found in a-Si:H. The decrease is incompatible with several popular noise models. Extrapolating the temperature trends for each geometry shows that it is possible that the noise observed in the transverse samples has the same origin as the higher frequency part of the double power law spectra observed in the longitudinal samples.Natural Sciences and Engineering Research Council of Canad