Host--parasite models on graphs

The behavior of two interacting populations, ``hosts''and ``parasites'', is investigated on Cayley trees and scale-free networks. In the former case analytical and numerical arguments elucidate a phase diagram, whose most interesting feature is the absence of a tri-critical point as a function of the two independent spreading parameters. For scale-free graphs, the parasite population can be described effectively by Susceptible-Infected-Susceptible-type dynamics in a host background. This is shown both by considering the appropriate dynamical equations and by numerical simulations on Barab\'asi-Albert networks with the major implication that in the termodynamic limit the critical parasite spreading parameter vanishes.Comment: 10 pages, 6 figures, submitted to PRE; analytics redone, new calculations added, references added, appendix remove

Computational complexity arising from degree correlations in networks

We apply a Bethe-Peierls approach to statistical-mechanics models defined on random networks of arbitrary degree distribution and arbitrary correlations between the degrees of neighboring vertices. Using the NP-hard optimization problem of finding minimal vertex covers on these graphs, we show that such correlations may lead to a qualitatively different solution structure as compared to uncorrelated networks. This results in a higher complexity of the network in a computational sense: Simple heuristic algorithms fail to find a minimal vertex cover in the highly correlated case, whereas uncorrelated networks seem to be simple from the point of view of combinatorial optimization.Comment: 4 pages, 1 figure, accepted in Phys. Rev.

PI3Kα inhibition reduces obesity in mice

Partial inhibition of PI3K is one of the best-validated and evolutionary conserved manipulations to extend longevity. The best known health beneficial effects of reduced PI3K are related to metabolism and include increased energy expenditure, reduced nutrient storage, and protection from obesity. We have previously shown that a dual chemical inhibitor of the alpha and delta PI3K isoforms (CNIO-PI3Ki) reduces obesity in mice and monkeys, without evident toxic effects after long-term treatment. Here, we dissect the role of the alpha and delta PI3K isoforms by making use of selective inhibitors against PI3Kα (BYL-719 also known as alpelisib) or PI3Kδ (GS-9820 also known as acalisib). Treatment of mice with the above mentioned inhibitors indicated that BYL-719 increases energy expenditure in normal mice and efficiently reduces body weight in obese (ob/ob) mice, whereas these effects were not observed with GS-9820. Of note, the dose of BYL-719 required to reduce obesity was 10x higher than the equivalent dose of CNIO-PI3Ki, which could suggest that simultaneous inhibition of PI3K alpha and delta is more beneficial than single inhibition of the alpha isoform. In summary, we conclude that inhibition of PI3Kα is sufficient to increase energy expenditure and reduce obesity, and suggest that concomitant PI3Kα inhibition could play an auxiliary role

Surface modification of Al2O3–ZrO2(Y2O3) eutectic oxides by laser melting: processing and wear resistance

Surface coatings of pseudo-binary Al2O3–Zr2O3(Y2O3) eutectic oxides were produced by laser melting of the surface of conventionally sintered materials using a high-power diode laser. It was possible to obtain smooth, homogeneous, and crack-free coatings up to 50_7 mm2 in area by carefully controlling the processing conditions (laser power, traveling speed of the specimen, and substrate temperature). The surface treatment was aimed at creating a dense, wear-resistant coating based on the eutectic microstructure generated upon solidification. The microstructure of the coating was formed by elongated colonies, and was similar to that found in rods grown by the laser-heated floating zone method at the same growth rates. The laser-melted coating presented much higher hardness and wear resistance than the sintered materials, and the optimum mechanical properties were measured in samples treated at 500 mm/h with a laser line power of 65–80 W/cm. These samples presented a hardness and wear rate of 19.770.4 GPa and 3.8_10_6 mm3/N m, respectively, while those of the conventionally sintered materials were 14.37 0.2 GPa and 2.3_10_6 mm3/N m

Investigating the land‑to‑sea transition in carnivorans from the evolution of sacrum morphology in pinnipeds

The form and function of the sacrum are of great relevance to understand the evolution of locomotion in tetrapods because it is a key piece of the vertebrate skeleton. The sacrum connects the caudal and presacral regions of the vertebral column and the hindlimbs through the pelvis. Here, we investigate sacrum shape evolution in pinnipeds (Carnivora: Pinnipedia) in relation to terrestrial mammalian carnivorans (fissipeds), and we include crown and stem taxa to quantify the morphological changes they experience in relation to the aquatic environment they inhabit. We use 3D geometric morphometric methods to explore the morphological variability and disparity of the sacrum in a set of terrestrial and aquatic carnivoran species. Our results show that the morphology of the sacrum of each pinniped family is remarkably different and that these differences may be related to the aquatic mode of locomotion (pectoral or pelvic oscillation), the use of hindlimbs to support body weight on land (otariids in contrast with phocids), and the presence or absence of a functional tail. In addition, disparity-through-time analyses indicate that the sacrum of pinnipeds is less constrained than that of fissipeds, which suggests a gravitational origin of such constraints in fissipeds. In conclusion, our results give further support to the important role played by this skeletal structure in the locomotory adaptations of mammals.Funding for open access publishing: Universidad Málaga/CBUA. This work has been funded by the Spanish Ministry of Science and Universities (Grant # PID2019-111185GB-I00) and Junta de Andalucía (Grant # P18-FR-3193). Support for laser scanning the specimen of Puijila darwini was provided by the Canadian Museum of Nature. Funding for open access charge: Universidad de Málaga / CBU

Multitasking Compensatory Saccadic Training Program for Hemianopia Patients: A New Approach With 3-Dimensional Real-World Objects

Producción CientíficaPurpose: To examinewhether a noncomputerized multitasking compensatory saccadic training program (MCSTP) for patients with hemianopia, based on a reading regimen and eight exercises that recreate everyday visuomotor activities using threedimensional (3D) real-world objects, improves the visual ability/function, quality of life (QL), and functional independence (FI). Methods: The 3D-MCSTP included four in-office visits and two customized homebased daily training sessions over 12weeks. A quasiexperimental, pretest/posttest study designwas carried out with an intervention group (IG) (n = 20) and a no-training group (NTG) (n = 20) matched for age, hemianopia type, and brain injury duration. Results: The groups were comparable for the main baseline variables and all participants (n = 40) completed the study. The IGmainly showed significant improvements in visual-processing speed (57.34% ± 19.28%; P < 0.0001) and visual attention/retention ability (26.67% ± 19.21%; P < 0.0001), which also were significantly greater (P < 0.05) than in the NTG. Moreover, the IG showed large effect sizes (Cohen’s d) in 75% of the totalQL and FI dimensions analyzed; in contrast to the NTGthat showed negligiblemean effect sizes in 96% of these dimensions. Conclusions: The customized 3D-MCSTP was associated with a satisfactory response in the IG for improving complex visual processing, QL, and FI. Translational Relevance: Neurovisual rehabilitation of patientswith hemianopia seems more efficient when programs combine in-office visits and customized home-based training sessions based on real objects and simulating real-life conditions, than no treatment or previously reported computer-screen approaches, probably because of better stimulation of patients´ motivation and visual-processing speed brain mechanisms

Final implementation of SEACON: new scope and new open system platform.

SEACON is a hybrid (heuristic & algorithmic) expert system for contingency analysis and preventive or corrective control of the transmission network, that has been recently redesigned to implement new end user requirements and to increase its performance. This paper describes the main results and the operational experience from the development and implementation of a new system based on the initial idea. Software reuse strategies became capital in this project. The new design includes advanced functionalities demanded by the practical use of the former system. Because of the high performance of the new system (up to fifteen times faster than the original) and its friendly user interface, SEACON has become a very valuable tool among dispatchers. SEACON is in operation in the Red Electrica’s National Control Centre and in Iberdrola’s Central and Regional Control Centres, dealing with transmission and subtransmission networks (ranging between 4OOkV and 66kV), attached to the on-line state estimators and screening over 2000 possible contingencies. Results are presented using natural language, and a client-server scheme provided for corporate access. KeywOrdr - Expert system, security assessment, contingency analysis, power systems, real-time system

Optimal procurement of flexibility services within electricity distribution networks

The increased injection of volatile renewable energy at local levels into the electricity grid is forcing the distribution network operators to seek participation in emerging service markets in order to obtain the flexibility required to balance their systems. However, the distribution companies lack experience in designing new market arrangements. We consider a market framework wherein a proactive distribution company is willing to purchase reserve capacity for overload management, using a two-part tariff. The problem is modelled as a three-stage stochastic market including Day-Ahead, Intra-Day and Real-Time, with uncertainty on both demand and generation. After assessing our formulation, we discuss the impact of risk-aversion at each stage with an objective function based on CVaR. Finally, different Intra-Day clearing horizons and delivery settings are evaluated. The results show that risk-aversion close to Real-Time becomes the main driver for decision makers and that early hedging strategies lead to sub-optimal solutions

Evaluation of flexibility markets for retailer-DSO-TSO coordination

The rise of distributed energy resources (DERs) can enhance the efficiency of system operations by providing flexibility services to the different agents involved, but they also pose a major resource allocation problem. This study considers three different agents procuring DER services: distribution system operators (DSOs) for local congestion management, transmission system operators (TSOs) for system-wide reserve deployment, and retailers for hedging against network usage tariffs based upon peak-load pricing. A variety of market mechanisms are identified to co-ordinate these needs, and three schemes are developed in detail. These are separate markets for each agent, co-ordinated Shapley value allocations for TSO and DSO, and a co-ordinated mechanism including retailers. These designs are evaluated on a realistic distribution network in Britain for two operational days. The results show a more efficient dispatch from the TSO–DSO co-ordinated procurement over independent sequential procurements. However, the inclusion of retailers in the joint dispatch is surprisingly less attractive due to the lack of improvement in social welfare and the undesirable impacts on the DSO

Plasmonic communications : light on a wire

The emerging field of plasmonics promises the generation, processing, transmission, sensing and detection of signals at optical frequencies along metallic surfaces much smaller than the wavelengths they carry. Plasmonic technology has applications in a wide range of fields, including biophotonics, sensing, chemistry and medicine. But perhaps the area where it will have the most profound impact is in optical communications, since plasmonic waves oscillate at optical frequencies and thus can carry information at optical bandwidths