On the zero crossing of the three-gluon vertex

We report on new results on the infrared behaviour of the three-gluon vertex in quenched Quantum Chormodynamics, obtained from large-volume lattice simulations. The main focus of our study is the appearance of the characteristic infrared feature known as 'zero crossing', the origin of which is intimately connected with the nonperturbative masslessness of the Faddeev-Popov ghost. The appearance of this effect is clearly visible in one of the two kinematic configurations analyzed, and its theoretical origin is discussed in the framework of Schwinger-Dyson equations. The effective coupling in the momentum subtraction scheme that corresponds to the three-gluon vertex is constructed, revealing the vanishing of the effective interaction at the exact location of the zero crossing.Comment: 6 pages, 4 figure

Instanton traces in lattice gluon correlation functions

Strong coupling constant computed in Landau gauge and MOM renormalization scheme from lattice two and three gluon Green Functions exhibits an unexpected behavior in the deep IR, showing a maximum value around $1 {\rm GeV}$. We analise this coupling below this maximum within a semiclassical approach, were gluon degrees of freedom at very low energies are described in terms of the classical solutions of the lagrangian, namely instantons. We provide some new results concerning the relationship between instantons and the low energy dynamics of QCD, by analising gluon two- and three-point Green functions separately and with the help of a cooling procedure to eliminate short range correlations.Comment: 4 pages, talk given at XXXX Rencontres de Moriond on QCD and Hadronic Interactions, La Thuile (Italy

Inductive Logic Programming for Transparent Alignment with Multiple Moral Values

Reinforcement learning is a key paradigm for developing intelligent agents that operate in complex environments and interact with humans. However, researchers face the need to explain and interpret the decisions of these systems, especially when it comes to ensuring their alignment with societal value systems. This paper marks the initial stride in an ongoing research direction by applying an inductive logic programming methodology to explain the policy learned by an RL algorithm in the domain of autonomous driving, thus increasing the transparency of the ethical behaviour of agents

Time and frequency pump-probe multiplexing to enhance the signal response of Brillouin optical time-domain analyzers

© 2014 Optical Society of America. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modifications of the content of this paper are prohibitedA technique to enhance the response and performance of Brillouin distributed fiber sensors is proposed and experimentally validated. The method consists in creating a multi-frequency pump pulse interacting with a matching multi-frequency continuous-wave probe. To avoid nonlinear cross-interaction between spectral lines, the method requires that the distinct pump pulse components and temporal traces reaching the photodetector are subject to wavelength-selective delaying. This way the total pump and probe powers launched into the fiber can be incrementally boosted beyond the thresholds imposed by nonlinear effects. As a consequence of the multiplied pump-probe Brillouin interactions occurring along the fiber, the sensor response can be enhanced in exact proportion to the number of spectral components. The method is experimentally validated in a 50 km-long distributed optical fiber sensor augmented to 3 pump-probe spectral pairs, demonstrating a signal-to-noise ratio enhancement of 4.8 dB.The authors would like to thank Mr. Javier Urricelqui from Universidad Publica de Navarra (Spain) for the valuable discussions and help in relation to the noise characteristics of BOTDA sensors. This work was performed in the framework and with the support of the COST Action TD1001 OFSeSa. M. A. Soto and L. Thevenaz acknowledge the support from the Swiss Commission for Technology and Innovation (Project 13122.1), and from the Swiss State Secretariat for Education, Research and Innovation (SERI) through the project COST C10.0093. UPVLC group acknowledges the support from the Spanish MICINN and the Valencia Government through the projects TEC2011-29120-C05-05 and ACOMP/2013/146, respectively. L. Zhang acknowledges the support from the China Scholarship Council during his stay at EPFL in Switzerland.Soto, MA.; Ricchiuti, AL.; Zhang, L.; Barrera Vilar, D.; Sales Maicas, S.; Thevenaz, L. (2014). Time and frequency pump-probe multiplexing to enhance the signal response of Brillouin optical time-domain analyzers. Optics Express. 22(23):28584-28595. https://doi.org/10.1364/OE.22.028584S28584285952223Horiguchi, T., Shimizu, K., Kurashima, T., Tateda, M., & Koyamada, Y. (1995). Development of a distributed sensing technique using Brillouin scattering. Journal of Lightwave Technology, 13(7), 1296-1302. doi:10.1109/50.400684Soto, M. A., & Thévenaz, L. (2013). Modeling and evaluating the performance of Brillouin distributed optical fiber sensors. Optics Express, 21(25), 31347. doi:10.1364/oe.21.031347Foaleng, S. M., & Thévenaz, L. (2011). Impact of Raman scattering and modulation instability on the performances of Brillouin sensors. 21st International Conference on Optical Fiber Sensors. doi:10.1117/12.885105Alem, M., Soto, M. A., & Thévenaz, L. (2014). Modelling the depletion length induced by modulation instability in distributed optical fibre sensors. 23rd International Conference on Optical Fibre Sensors. doi:10.1117/12.2058862Thévenaz, L., Mafang, S. F., & Lin, J. (2013). Effect of pulse depletion in a Brillouin optical time-domain analysis system. Optics Express, 21(12), 14017. doi:10.1364/oe.21.014017Minardo, A., Bernini, R., & Zeni, L. (2009). A Simple Technique for Reducing Pump Depletion in Long-Range Distributed Brillouin Fiber Sensors. IEEE Sensors Journal, 9(6), 633-634. doi:10.1109/jsen.2009.2019372Soto, M. A., Bolognini, G., Di Pasquale, F., & Thévenaz, L. (2010). Simplex-coded BOTDA fiber sensor with 1 m spatial resolution over a 50 km range. Optics Letters, 35(2), 259. doi:10.1364/ol.35.000259Soto, M. A., Bolognini, G., & Di Pasquale, F. (2010). Analysis of pulse modulation format in coded BOTDA sensors. Optics Express, 18(14), 14878. doi:10.1364/oe.18.014878Rodriguez-Barrios, F., Martin-Lopez, S., Carrasco-Sanz, A., Corredera, P., Ania-Castanon, J. D., Thevenaz, L., & Gonzalez-Herraez, M. (2010). Distributed Brillouin Fiber Sensor Assisted by First-Order Raman Amplification. Journal of Lightwave Technology, 28(15), 2162-2172. doi:10.1109/jlt.2010.2051141Martin-Lopez, S., Alcon-Camas, M., Rodriguez, F., Corredera, P., Ania-Castañon, J. D., Thévenaz, L., & Gonzalez-Herraez, M. (2010). Brillouin optical time-domain analysis assisted by second-order Raman amplification. Optics Express, 18(18), 18769. doi:10.1364/oe.18.018769Soto, M. A., Bolognini, G., & Di Pasquale, F. (2011). Optimization of long-range BOTDA sensors with high resolution using first-order bi-directional Raman amplification. Optics Express, 19(5), 4444. doi:10.1364/oe.19.004444Soto, M. A., Taki, M., Bolognini, G., & Pasquale, F. D. (2012). Simplex-Coded BOTDA Sensor Over 120-km SMF With 1-m Spatial Resolution Assisted by Optimized Bidirectional Raman Amplification. IEEE Photonics Technology Letters, 24(20), 1823-1826. doi:10.1109/lpt.2012.2212183Jia, X.-H., Rao, Y.-J., Yuan, C.-X., Li, J., Yan, X.-D., Wang, Z.-N., … Peng, F. (2013). Hybrid distributed Raman amplification combining random fiber laser based 2nd-order and low-noise LD based 1st-order pumping. Optics Express, 21(21), 24611. doi:10.1364/oe.21.024611Soto, M. A., Angulo-Vinuesa, X., Martin-Lopez, S., Chin, S.-H., Ania-Castanon, J. D., Corredera, P., … Thevenaz, L. (2014). Extending the Real Remoteness of Long-Range Brillouin Optical Time-Domain Fiber Analyzers. Journal of Lightwave Technology, 32(1), 152-162. doi:10.1109/jlt.2013.2292329Soto, M. A., Bolognini, G., & Pasquale, F. D. (2009). Distributed optical fibre sensors based on spontaneous Brillouin scattering employing multimode Fabry-Pérot lasers. Electronics Letters, 45(21), 1071. doi:10.1049/el.2009.2381Li, C., Wang, F., Lu, Y., & Zhang, X. (2012). SNR enhancement in Brillouin optical time domain reflectometer using multi-wavelength coherent detection. Electronics Letters, 48(18), 1139-1141. doi:10.1049/el.2012.1248Voskoboinik, A., Wang, J., Shamee, B., Nuccio, S. R., Zhang, L., Chitgarha, M., … Tur, M. (2011). SBS-Based Fiber Optical Sensing Using Frequency-Domain Simultaneous Tone Interrogation. Journal of Lightwave Technology, 29(11), 1729-1735. doi:10.1109/jlt.2011.2145411Voskoboinik, A., Yilmaz, O. F., Willner, A. W., & Tur, M. (2011). Sweep-free distributed Brillouin time-domain analyzer (SF-BOTDA). Optics Express, 19(26), B842. doi:10.1364/oe.19.00b842Chaube, P., Colpitts, B. G., Jagannathan, D., & Brown, A. W. (2008). Distributed Fiber-Optic Sensor for Dynamic Strain Measurement. IEEE Sensors Journal, 8(7), 1067-1072. doi:10.1109/jsen.2008.926107Nikles, M., Thevenaz, L., & Robert, P. A. (1997). Brillouin gain spectrum characterization in single-mode optical fibers. Journal of Lightwave Technology, 15(10), 1842-1851. doi:10.1109/50.633570Jacobs, I. (1995). Dependence of optical amplifier noise figure on relative-intensity-noise. Journal of Lightwave Technology, 13(7), 1461-1465. doi:10.1109/50.400712Bolognini, G., Soto, M. A., & Di Pasquale, F. (2009). Fiber-Optic Distributed Sensor Based on Hybrid Raman and Brillouin Scattering Employing Multiwavelength Fabry–PÉrot Lasers. IEEE Photonics Technology Letters, 21(20), 1523-1525. doi:10.1109/lpt.2009.202889

Instanton liquid properties from lattice QCD

We examined the instanton contribution to the QCD configurations generated from lattice QCD for N-F = 0, N-F = 2 + 1 and NF = 2 + 1 + 1 dynamical quark flavors from two different and complementary approaches. First via the use of Gradient flow, we computed instanton liquid properties using an algorithm to localize instantons in the gauge field con figurations and studied their evolution with flow time. Then, the analysis of the running at low momenta of gluon Green\u27s functions serves as an independent confirmation of the instanton density which can also be derived without the use of the Gradient flow

A 0535+26: an X-ray/Optical Tour

We compiled X-ray and Optical observations of the accreting X-ray binary system A 0535+262 since its discovery in 1975, that will allow us to shed light on the unpredictable behavior of this binary system. We present the data in terms of the Be-disk interaction with the neutron star companion. In addition, we show recent results from the continuous monitoring of this source by the Gamma-ray Burst Monitor(GBM), on board the Fermi observatory, since its launch in 2008 June 11.Comment: 4 pages, 5 figures, Conference proceeding of "Astrophysics of Neutron Stars 2010 - a conference in honor of M. Ali Alpar", 2-6 August 2010, Cesme, Izmir, Turke

Instilling moral value alignment by means of multi-objective reinforcement learning

AI research is being challenged with ensuring that autonomous agents learn to behave ethically, namely in alignment with moral values. Here, we propose a novel way of tackling the value alignment problem as a two-step process. The first step consists on formalising moral values and value aligned behaviour based on philosophical foundations. Our formalisation is compatible with the framework of (Multi-Objective) Reinforcement Learning, to ease the handling of an agent's individual and ethical objectives. The second step consists in designing an environment wherein an agent learns to behave ethically while pursuing its individual objective. We leverage on our theoretical results to introduce an algorithm that automates our two-step approach. In the cases where value-aligned behaviour is possible, our algorithm produces a learning environment for the agent wherein it will learn a value-aligned behaviour

Cycle of Knowledge in the Management of the Supply Chain of Corn for Human Consumption

The objective of this study is to characterize the cycle of knowledge in the supply chain of the industry of corn for human consumption. White corn is cultivated almost exclusively for human consumption and it has a significant value in the food supply in countries whose diet has a high proportion of this variety of corn, such as: Venezuela, México and Colombia in America, and the Republic of South Africa and Sahel countries in Africa. Corn is produced in Venezuela, under rainfed conditions and in a highly mechanized production system. The cycle of knowledge is defined as a progressive spiral in which knowledge is created, stored, transferred, applied and preserved, in order to increase the competitiveness and  sustainability of organizations and companies in the food supply chain. This non experimental and crosssectional research is of a descriptive type. It was conducted in Venezuela during the second semester of 2009 in the supply chain of white corn, specifically, at the level of first tier producers (primary sector). The population is constituted by 1,754 producers of corn in the most important producing regions of the country. The representative sample was selected by the stratified sampling technique with proportional allocation: by association of corn producers and according to the grain yield. A questionnaire was designed and conducted according to the structured survey method. Its validity was verified by discriminant tests of items and its reliability through Bartlett's test, variance factorial analysis, Kaiser/Meyer/Olkin and Cronbach Alpha, achieving the last one a value of 0.9276.The production units have an average area of 67.17 ha, with 1.97 permanent workers and 4.06 temporary workers. They obtained a physical productivity of 4,210.45 kg/ha. The Knowledge Index (KI) achieved a value of 69.78% and the Perception Index of the results (PI) was 76.06%. The Pearson correlation among these indices was positive and significant with a value of 0.51. The factorial analysis for principal components with rotated factors allows obtaining four factors from the five dimensions originally considered. These factors are: (1) knowledge creation, (2) knowledge storage, (3) knowledge transfer and application, and (4) preservation of knowledge.The results allow us to conclude that the cycle of knowledge is managed in four stages in an intuitive and predominantly tacit manner which is the reason why those practices related to explicit knowledge become the agents of differentiation. Moreover, the existence of a positive correlation between the Knowledge Index and the Perception Index of the positive results by the producer was also proven

Protective effects of eicosapentaenoic acid plus hydroxytyrosol supplementation against white adipose tissue abnormalities in mice fed a high-fat diet

Objective: Obesity induced by high-fat diet (HFD) elicits white adipose tissue dysfunction. In this study, we have hypothesized that the metabolic modulator eicosapentaenoic acid (EPA) combined with the antioxidant hydroxytyrosol (HT) attenuates HFD-induced white adipose tissue (WAT) alterations. Methods: C57BL/6J mice were administered with a HFD (60% fat, 20% protein, 20% carbohydrates) or control diet (CD; 10% fat, 20% protein, 70% carbohydrates), with or without EPA (50 mg/kg/day), HT (5 mg/kg/day), or both for 12 weeks. Determinations in WAT include morphological parameters, EPA and docosahexaenoic acid content in phospholipids (gas chromatography), lipogenesis, oxidative stress (OS) and inflammation markers, and gene expression and activities of transcription factors, such as sterol regulatory element-binding protein-1c (SREBP-1c), peroxisome proliferator-activated receptor-gamma (PPAR-γ), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) (p65 subunit) and nuclear factor erythroid 2-related factor 2 (Nrf2) (quantitative polymerase chain reaction and enzyme linked immunosorbent assay). Results: HFD led to WAT hypertrophy in relation to PPAR-γ downregulation. WAT metabolic dysfunction was characterized by upregulation of lipogenic SREBP-1c system, mitochondrial energy metabolism depression, loss of the antioxidant Nrf2 signaling with OS enhancement, n-3 long-chain polyunsaturated fatty acids depletion and activation of the pro-inflammatory NF-κB system. EPA and HT co-supplementation diminished HFD-dependent effects additively, reaching values close or similar to controls. Conclusion: Data presented strengthen the importance of combined protocols such as EPA plus HT to attenuate metabolic-inflammatory states triggered by obesity

Redesign of an informed consent form to increase participation in a school-based dental program

Objectives The study aimed to determine if modifications to the design of a consent form and consenting process increased participation rates in the Indiana University School of Dentistry's Mobile School-Based Dental Program (Seal Indiana). Methods Kaizen methodology was followed to identify problem areas in the consenting process. Additionally, stakeholders were invited to participate in focus groups and fill out surveys to identify issues preventing participation in the Seal Indiana program (N = 48) and later to evaluate the changes made (N = 48). The redesigned form and process were then used in a pilot study at 14 sites to determine the impact that changes had on levels of participation as measured by the number of consent forms completed and returned. Results There was a statistically significant increase in the number of consent forms returned. The measured change represented a 32 percent increase in program participation (P value = 0.035). A statistically significant increase was observed in how participants viewed the attractiveness of the form and how easy it was to read and comprehend. Conclusions In order to increase consenting rates, our results indicate modifications to the consent form should be focused on the following characteristics: esthetics, ease of reading and comprehending information, and making the Health Insurance Portability and Accountability Act of 1996 (HIPPA) privacy regulations easier to read and comprehend