cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Companies and Society. The 7 Elements of Action. A Contribution from the Plate to the Farm
Creators: name: Senesi, Sebastián
name: Palau, Hernán
name: Neves, Marcos Fava
Publisher: name: International Journal on Food System Dynamics
Year: 2021
Subjects: agribusiness; globalization; local foods; consumers; policy; adaptation

description: The emergence of the COVID-19 pandemic has generated great changes in society and business, particularly agribusiness. Consumers are more demanding, some countries have increased restrictive policies and retail has changed dramatically. The impact is everywhere. The purpose of this position paper is to summarize what we believe may happen in a short term period at the level of agribusiness. We will establish seven critical areas of change that may occur at this juncture considering both the Argentine and global situation. These areas are: a) the role of consumers, b) economy and business management, c) digitalization and connectivity, d) workforce changes, e) regenerative business models, f) behavior, g) protectionism and government intervention. Every topic is presented in a systemic view, taking into account the situation both in developed and underdeveloped countries. This approach implies the definition of a series of situations at a group and individual level that —sooner or later and at a greater or lesser level of occurrence— will allow us to make better decisions at work, personally and as a society. Covid-19 took into consideration the processes associated with globalization and de-globalization. The irruption of a new information and knowledge society reveals demands for transformations and challenges for organizations with a special connotation on people and their interaction with society. In this context, organizations must respond with actions that allow them to be sustainable over time. Studying these changes enables the identification of possible nstitutional, organizational, and technological adaptations for agri-food companies, policymakers, NGO’s managers, etc.
description: International Journal on Food System Dynamics, Vol 12, No 1 (2021)
Nano-Thermodynamics: On the minimal length scale for the existence of temperature
Creators: name: Hartmann, M.
name: Mahler, G.
name: Hess, O.
Publisher: name: arXiv
Year: 2005
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We consider a quantum system consisting of a regular chain of elementary subsystems with nearest neighbor interactions and assume that the total system is in a canonical state with temperature $T$. We analyze under what condition the state factors into a product of canonical density matrices with respect to groups of $n$ subsystems each, and when these groups have the same temperature $T$. While in classical mechanics the validity of this procedure only depends on the size of the groups $n$, in quantum mechanics the minimum group size $n_{\text{min}}$ also depends on the temperature $T $! As examples, we apply our analysis to a harmonic chain and an Ising spin chain. We discuss various features that show up due to the characteristics of the models considered. For the harmonic chain, which successfully describes thermal properties of insulating solids, our approach gives a first quantitative estimate of the minimal length scale on which temperature can exist: This length scale is found to be constant for temperatures above the Debye temperature and proportional to $T^{-3}$ below.
description: submitted to Proceedings of the FQMT04 conference, July 2004 in Prague, Czech Republic
A Delphi Study on Blockchain Application to Food Traceability
Creators: name: Aldrighetti, Anna
name: Canavari, Maurizio
name: Hingley, Martin K.
Publisher: name: International Journal on Food System Dynamics
Year: 2021
Subjects: Blockchain; Food Traceability; Food Safety; Supply Chain Management

description: Blockchain has been described as a breakthrough Information and Communication Technology having the potential to ensure safe, immutable and transparent information exchange between actors. This study attempts to foresee whether Blockchain will play an important role in traceability management and how this innovation is expected to change the agri-food sector's future, using a Delphi group discussion with experts. According to our results, blockchain is potentially recognised as a decentralised system able not only to harmonise safety and quality standards but also to reduce bureaucracy. Greater efficiency and reliability of the system would lead to the establishment and coordination of new supply chain relationships.
description: International Journal on Food System Dynamics, Vol 12, No 1 (2021)
The Impact of a Visual Cheap Talk Script in an Online Choice Experiment
Creators: name: Ellis, Jade
name: Delong, Karen L.
name: Jensen, Kimberly L.
name: Griffith, Andrew P.
Publisher: name: International Journal on Food System Dynamics
Year: 2021
Subjects: Cheap talk; willingness to pay; visual and verbal learners

description: Hypothetical bias causes willingness to pay (WTP) values to be inaccurate and is a prevalent issue in choice experiments. Research has shown that a “cheap talk” script may reduce hypothetical bias ; however, it is uncertain which cheap talk script format is the best at controlling hypothetical bias . Therefore, we conduct a choice experiment using a between-subjects design in which half of the articipants saw a “visual” cheap talk script and half saw a “text” cheap talk script prior to the choice sets. Random parameter logit model results indicate hypothetical bias was more prevalent when participants saw the visual cheap talk script compared to the more conventional text cheap talk script. Text learners also appeared to be less prone to hypothetical bias than visual learners.
description: International Journal on Food System Dynamics, Vol 12, No 1 (2021)
A No-Lose Theorem for Discovering the New Physics of $(g-2)_μ$ at Muon Colliders
Creators: name: Capdevilla, Rodolfo
name: Curtin, David
name: Kahn, Yonatan
name: Krnjaic, Gordan
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: We perform a model-exhaustive analysis of all possible beyond Standard Model (BSM) solutions to the $(g-2)_μ$ anomaly to study production of the associated new states at future muon colliders, and formulate a no-lose theorem for the discovery of new physics if the anomaly is confirmed and weakly coupled solutions below the GeV scale are excluded. Our goal is to find the highest possible mass scale of new physics subject only to perturbative unitarity, and optionally the requirements of minimum flavour violation (MFV) and/or naturalness. We prove that a 3 TeV muon collider is guaranteed to discover all BSM scenarios in which $Δa_μ$ is generated by SM singlets with masses above $\sim $ GeV; lighter singlets will be discovered by upcoming low-energy experiments. If new states with electroweak quantum numbers contribute to $(g-2)_μ$, the minimal requirements of perturbative unitarity guarantee new charged states below $\mathcal{O}(100 {\rm TeV})$, but this is strongly disfavoured by stringent constraints on charged lepton flavour violating (CLFV) decays. Reasonable BSM theories that satisfy CLFV bounds by obeying Minimal Flavour Violation (MFV) and avoid generating two new hierarchy problems require the existence of at least one new charged state below $\sim 10$ TeV. This strongly motivates the construction of high-energy muon colliders, which are guaranteed to discover new physics: either by producing these new charged states directly, or by setting a strong lower bound on their mass, which would empirically prove that the universe is fine-tuned and violates the assumptions of MFV while somehow not generating large CLFVs. The former case is obviously the desired outcome, but the latter scenario would perhaps teach us even more about the universe by profoundly revising our understanding of naturalness, cosmological vacuum selection, and the SM flavour puzzle.
description: 56 pages, 9 figures, 5 tables. Added references, fixed typos, no significant change to results/conclusions. Corrected NBSM dependence of naturalness bound for EW Scenarios, slightly strengthening theorem. Added discussion of EW Scenarios with fewer BSM states (Sec 4.8). Added discussion of avoiding Landau poles to the Planck scale (Sec 4.9). Added comment on higher loop scenarios (Sec 2)
Self-consistent theory of turbulent transport in the solar tachocline. II. Tachocline confinement
Creators: name: Leprovost, Nicolas
name: Kim, Eun-Jin
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: Classical Physics (physics.class-ph)
subject: FOS: Physical sciences

description: We provide a consistent theory of the tachocline confinement (or anisotropic momentum transport) within an hydrodynamical turbulence model. The goal is to explain helioseismological data, which show that the solar tachocline thickness is at most 5% of the solar radius, despite the fact that, due to radiative spreading, this transition layer should have thickened to a much more significant value during the sun's evolution. Starting from the first principle with the physically plausible assumption that turbulence is driven externally (e.g. by plumes penetrating from the convection zone), we derive turbulent (eddy) viscosity in the radial (vertical) and azimuthal (horizontal) directions by incorporating the crucial effects of shearing due to radial and latitudinal differential rotations in the tachocline. We show that the simultaneous presence of both shears induces effectively a much more efficient momentum transport in the horizontal plane than in the radial direction. In particular, in the case of strong radial turbulence (driven by overshooting plumes from the convection zone), the ratio of the radial to horizontal eddy viscosity is proportional to ${\cal A}^{-1/3}$, where ${\cal A}$ is the strength of the shear due to radial differential rotation. In comparison, in the case of horizontally driven turbulence, this ratio becomes of order $-ε^2$, with negative radial eddy viscosity. Here, $ε$ ($\ll 1$) is the ratio of the radial to latitudinal shear. The resulting anisotropy in momentum transport could thus be sufficiently strong to operate as a mechanism for the tachocline confinement against spreading.
Hierarchical Features of Large-Scale Cortical Connectivity
Creators: name: Costa, Luciano da F.
name: Sporns, Olaf
Publisher: name: arXiv
Year: 2005
Subjects: subject: Neurons and Cognition (q-bio.NC)
subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: Quantitative Methods (q-bio.QM)
subject: FOS: Biological sciences
subject: FOS: Physical sciences

description: The analysis of complex networks has revealed patterns of organization in a variety of natural and artificial systems, including neuronal networks of the brain at multiple scales. In this paper, we describe a novel analysis of the large-scale connectivity between regions of the mammalian cerebral cortex, utilizing a set of hierarchical measurements proposed recently. We examine previously identified functional clusters of brain regions in macaque visual cortex and cat cortex and find significant differences between such clusters in terms of several hierarchical measures, revealing differences in how these clusters are embedded in the overall cortical architecture. For example, the ventral cluster of visual cortex maintains structurally more segregated, less divergent connections than the dorsal cluster, which may point to functionally different roles of their constituent brain regions.
description: 17 pages, 6 figures
A general method for estimating the prevalence of Influenza-Like-Symptoms with Wikipedia data
Creators: name: De Toni, Giovanni
name: Consonni, Cristian
name: Montresor, Alberto
Publisher: name: arXiv
Year: 2020
Subjects: subject: Computers and Society (cs.CY)
subject: Machine Learning (cs.LG)
subject: Social and Information Networks (cs.SI)
subject: FOS: Computer and information sciences

description: Influenza is an acute respiratory seasonal disease that affects millions of people worldwide and causes thousands of deaths in Europe alone. Being able to estimate in a fast and reliable way the impact of an illness on a given country is essential to plan and organize effective countermeasures, which is now possible by leveraging unconventional data sources like web searches and visits. In this study, we show the feasibility of exploiting information about Wikipedia's page views of a selected group of articles and machine learning models to obtain accurate estimates of influenza-like illnesses incidence in four European countries: Italy, Germany, Belgium, and the Netherlands. We propose a novel language-agnostic method, based on two algorithms, Personalized PageRank and CycleRank, to automatically select the most relevant Wikipedia pages to be monitored without the need for expert supervision. We then show how our model is able to reach state-of-the-art results by comparing it with previous solutions.
An Appraisal of Traceability Systems for Food Supply Chains in Colombia
Creators: name: Herrera, Milton M.
name: Orjuela-Castro, Javier
Publisher: name: International Journal on Food System Dynamics
Year: 2021
Subjects: food industry; supply chain; traceability system; performance; food quality; system dynamics

description: Traceability systems have improved significantly in the last few years in relation to safeguarding food safety and quality. Although traceability is considered to be an effective tool in supporting quality control, the adoption of different traceability systems along the supply chain can bring the drawback of information asymmetry, which affects inventory management. This paper explores adoption alternatives that may facilitate the blend of traceability technologies in the food industry of developing countries. The analysis is based on a simulation model that represents the behaviour of inventory and food quality in the case of the mango supply chain in Colombia. The results show the asymmetries between traceability systems along the supply chain as well as their effects on inventory and food quality.
description: International Journal on Food System Dynamics, Vol 12, No 1 (2021)
Modeling of Salt Supply Chains to Achieve Competitive Salt Prices
Creators: name: Muhandhis, Isnaini
name: Wirjodirdjo, Budisantoso
name: Suryani, Erma
name: Susanto, Heri
name: Asfari, Ully
Publisher: name: International Journal on Food System Dynamics
Year: 2021
Subjects: land integration; salt losses; policy; self-sufficiency; competitive price

description: To achieve the self-sufficiency of salt, prices need to be considered. This study develops a dynamic simulation model of salt supply chains to analyze the significant factors affecting prices from upstream to Indonesia's downstream levels. A set of dynamic simulation models is developed to achieve competitive prices using system dynamics. Furthermore, the system dynamics framework is utilized because it can model non-linear behavior between variables with a significant contribution to the system. Based on the simulation results, local and imported salt prices may compete by implementing land integration systems. This system is likely to reduce production costs and increase farmers' revenues to IDR 61,211,892 at the end of the simulation in 2035.
description: International Journal on Food System Dynamics, Vol 12, No 1 (2021)
Value Chain Upgrading through Producer Organisations: Linking Smallholder Vegetable Farmers with Modern Retail Markets in Indonesia
Creators: name: Widadie, Fanny
name: Bijman, Jos
name: Trienekens, Jacques
Publisher: name: International Journal on Food System Dynamics
Year: 2021
Subjects: Modern retail; Indonesia; producer organisation; value chain; upgrading

description: The study uses three elements of value chain analysis (VCA) – network structure, added value, and governance – to explore upgrading possibilities of value chains of producer organisations (PO)s in Indonesia in order to link smallholders to the modern retail market. Qualitative data are obtained through semi-structured interviews with PO members and other value chain actors. POs upgrade their value chains through linking smallholders with the modern retail market. Upgrading network structures is achieved by building collaboration between PO members and buyers. Upgrading added value is obtained by increasing the capability of farmers to meet quality requirements. Upgrading of governance structures in the chains is reached through contracts as vertical governance mechanisms and enhanced member services as horizontal arrangements.
description: International Journal on Food System Dynamics, Vol 12, No 1 (2021)
Simulations of the merging galaxy cluster Abell 2034: what determines the level of separation between gas and dark matter
Creators: name: Moura, Micheli T.
name: Machado, Rubens E. G.
name: Monteiro-Oliveira, Rogério
Publisher: name: arXiv
Year: 2020
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: Cluster mergers are an important laboratory for studying the behaviour of dark matter (DM) and intracluster gas. There are dissociative collisions that can separate the intracluster gas from the DM. Abell 2034 presents clear dissociative features observed by X-rays and gravitational lensing. The cluster, at $z$ = 0.114, consists of two substructures with mass ratio of about 1:2.2, separated by $\sim$720 kpc. The X-ray emission peak is offcentred from the south DM peak by $\sim$350 kpc. Using N-body hydrodynamical simulations, we aim to reconstruct the dynamic history of the collision, reproducing the observed features, and also to explore the conditions that led to the dissociation. Our best model assuming that the collision is close to the plane of the sky, with a small impact parameter, observed 0.26 Gyr after central passage, reproduces the observed features of this cluster, such as the offset between X-ray and DM peaks, X-ray morphology and temperatures. We explored several variations using different gas and DM concentrations for each cluster. The level of dissociation was quantified by the distances between X-ray and DM peaks, and also by the gas retention in the cluster cores. We found that the ratio of central gas densities is more important than the ratio of central DM densities in determining the level of dissociation.
description: 12 pages, 13 figures, 2 tables. Accepted for publication in MNRAS
Foodstragramming of Solo Dining Experiencescape: The Fear of Missing Out
Creators: name: Handayani, Bintang
Publisher: name: International Journal on Food System Dynamics
Year: 2021
Subjects: culinary tourism; introversion; foodstragramming; ramen; solo dining experiencescape

description: This study explored the foodstragramming or consumption photo-sharing and the solo dining experiencescape. Solo dining experiencescape is framed by culinary tourists and food neophobia of Instagram users. The narrative approach was employed to explore an Instagram post on Brooklyn ramen shop by BuzzFeed’s Tasty in relation to food-related personality traits and perceived territoriality. The collaborative branding of culinary tourism experiencescape denotes the use of Instagram. Introverted Instagram users were found to be co-creators, but food-related personality traits did not exclusively construct their visit plan. As the perceived territoriality and social distancing were found to augment foodstragramming of solo dining in this study, the visit plan of solo dining in culinary tourism was not solely perceived by introverted people. The use of the narrative approach in this study provided unique and valuable insights to these theoretical perspectives that may be overlooked by other analyses or approaches.
description: International Journal on Food System Dynamics, Vol 12, No 1 (2021)
The role of mitogen-activated protein kinases in Listeria monocytogenes invasion
Creators: name: Tang, Patrick
Publisher: name: University of British Columbia
Year: 2009

description: Listeria monocytogenes is a facultative intracellular gram-positive bacterium that causes severe disease in newborns, the elderly and immunocompromised people. The disease listeriosis has a high mortality rate in susceptible people and usually manifests as septicemia, meningitis or meningoencephalitis. The pathogenesis of L. monocytogenes infection depends upon the ability of the bacterium to invade and replicate inside various cell types, including macrophages and epithelial cells. Using an in vitro model of invasion, we have uncovered mitogen-activated protein (MAP) kinase signal transduction cascades that are induced in the host epithelial cells during the L. monocytogenes infection process. MAP kinase pathways are involved in the regulation of many eucaryotic cell functions including mitogenesis, differentiation, stress responses, apoptosis, and cytoskeletal rearrangements. Activation of the extracellular signal-regulated kinase-2 (ERK-2) and p38 MAP kinase seems to be specific for internalization of L. monocytogenes, while ERK-1 and c-Jun N-terminal kinase (JNK) are not. Initially, we found that ERK-1 and ERK-2 were tyrosine phosphorylated during L. monocytogenes infection of cultured epithelial cells. Subsequently, the action of a Listeria secreted cytolysin listeriolysin O(LLO) was shown to be responsible for triggering most of the MAP kinase activity, presumably through damage to the host eucaryotic cell membrane. However, LLO is not involved in the invasion process and thus not all of these signals were required for L. monocytogenes invasion. Using mutants lacking functional LLO, we found that ERK-2 and p38 activity was induced during invasion. In addition, PD98059, a specific inhibitor of MAPK/ERK kinase-1 (MEK-1) activation, blocked Listeria monocytogenes invasion into host cells but not adherence. MEK-1 is a kinase which activates ERK-1 and ERK-2. The effects of PD98059 were reversible as adherent extracellular bacteria were internalized upon removal of the drug. SB203580, a selective inhibitor of p38 activity, also decreased L. monocytogenes invasion into host cells. The invasion of Salmonella typhimurium was not affected by these drugs. These results indicate that the MEK-1/ERK-2 and p38 MAP kinase pathways are required for L. monocytogenes invasion into host epithelial cells.
Frequency resolved radio and high-energy emission of pulsars
Creators: name: Giraud, Quentin
name: Pétri, Jérôme
Publisher: name: arXiv
Year: 2020
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: Context. Pulsars are detected as broadband electromagnetic emitters from the radio wavelength up to high and very high energy in the MeV/GeV and sometimes even in the TeV range. Multi-wavelength phase-resolved spectra and light curves offer an unrivalled opportunity to understand their underlying radiation mechanisms and to localize their emission sites and therefore the particle acceleration regions. Aims. In this paper, we compute pulsars multi-wavelength phase-resolved light-curves and spectra assuming that curvature radiation operates from inside the magnetosphere of a rotating vacuum magnet. Radio emission arises from the polar caps whereas gamma-ray energy emanates from the slot gaps in the vicinity of the separatrix between closed and open field lines. Methods. By integrating particle trajectories within the slot gaps, we compute energy dependent photon sky maps in the radio band (MHz-GHz) and in the gamma-ray band (MeV/GeV) for mono-energetic distribution functions of leptons. Results. We obtained many details of the energy dependent light curves and phase-resolved spectra from the radio wavelength up to the gamma-ray energies. Choosing Lorentz factors of γ = 30 for radio emitting particles and γ = 10^7 for gamma-ray emitting particles, we found realistic spectra accounting for the wealth of multi-wavelength pulsar observations.
description: 38 pages, 37 figures
Activation of stress-activated kinases and inhibition of PI 3-K/PKB and p70S6K mitogenic signaling pathway by photodynamic therapy in murine keratinocytes
Creators: name: Tao, Jing-Song
Publisher: name: University of British Columbia
Year: 2009

description: Photodynamic therapy (PDT) is a new anti-cancer modality. It involves the use of photosensitizer molecules and a specific wavelength of visible light. The process of PDT generates singlet oxygen and other reactive oxygen intermediates (ROI). Cellular responses to PDT include induction of the early-response gene, release of cytokine, and apoptosis. Many of these cellular events are also known to be regulated by signaling pathways including members of the MAPK family and the PI 3-K/PKB/p70[sup S6K] mitogenic signaling pathway. We investigated the activation status of mitogen-activated protein kinases (MAPKs) and the phosphatidylinositol-3-kinase (PI3-K)/protein kinase B (PKB)/ p70[sup S6K] pathway following PDT treatment. We demonstrate here that PDT caused a marked, dose- and time-dependent activation of both stress-activated protein kinase (SAPK) and p38 HOG1 without affecting the activity of ERK1 or ERK2. However, under similar experimental conditions, PDT concomitantly inhibits the activity and phosphorylation of p70[sup S6K] in cells maintained in a serum-containing medium. In serum-starved Pam 212 cells, PDT inhibited the activation of PI3-K, PKB , and p70[sup S6K] induced by insulin treatment. At present, we do not understand the mechanisms for PDT-induced signaling events nor do we know the potential implications of our findings. However, some of the possible mechanisms and potential implications are discussed.
The eccentricity in heavy-ion collisions from Color Glass Condensate initial conditions
Creators: name: Adil, Azfar
name: Drescher, Hans-Joachim
name: Dumitru, Adrian
name: Hayashigaki, Arata
name: Nara, Yasushi
Publisher: name: arXiv
Year: 2006
Subjects: subject: Nuclear Theory (nucl-th)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: Nuclear Experiment (nucl-ex)
subject: FOS: Physical sciences

description: The eccentricity in coordinate-space at midrapidity of the overlap zone in high-energy heavy-ion collisions predicted by the $k_\perp$-factorization formalism is generically larger than expected from scaling with the number of participants. We provide a simple qualitative explanation of the effect which shows that it is not caused predominantly by edge effects. We also show that it is quite insensitive to ``details'' of the unintegrated gluon distribution functions such as the presence of leading-twist shadowing and of an extended geometric scaling window. The larger eccentricity increases the azimuthal asymmetry of high transverse momentum particles. Finally, we point out that the longitudinal structure of the Color Glass Condensate initial condition for hydrodynamics away from midrapidity is non-trivial but requires understanding of large-$x$ effects.
description: 8 pages, 7 figures; v3: added note regarding Qs2~n_part versus Qs2~T_A, final version to appear in PRC
Entanglement of remote atomic qubits
Creators: name: Matsukevich, D. N.
name: Chaneliere, T.
name: Jenkins, S. D.
name: Lan, S. -Y.
name: Kennedy, T. A. B.
name: Kuzmich, A.
Publisher: name: arXiv
Year: 2005
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We report observations of entanglement of two remote atomic qubits, achieved by generating an entangled state of an atomic qubit and a single photon at Site A, transmitting the photon to Site B in an adjacent laboratory through an optical fiber, and converting the photon into an atomic qubit. Entanglement of the two remote atomic qubits is inferred by performing, locally, quantum state transfer of each of the atomic qubits onto a photonic qubit and subsequent measurement of polarization correlations in violation of the Bell inequality |S| <2. We experimentally determine S =2.16 +/- 0.03. Entanglement of two remote atomic qubits, each qubit consisting of two independent spin wave excitations, and reversible, coherent transfer of entanglement between matter and light, represent important advances in quantum information science.
description: 5 pages, 3 figures
Comment on: "Solving many-body Schrödinger equations with kinetic energy partition method'', Ann. Phys. 388 (2018) 54-68 by Y-H. Chen and S. D. Chao
Creators: name: Fernández, Francisco M.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We discuss a recent test of the performance of the kinetic energy partition method (KEP) through its application to two separable quantum-mechanical models. We argue that one of the benchmark models is exceedingly simple for testing any realistic approximate method and that almost any reasonable approach yields better results. In the second example our exact benchmark eigenvalues disagree considerably with those chosen by the authors for comparison, which casts doubts on the accuracy of their KEP approach.
Quantifying systematic uncertainties in supernova cosmology
Creators: name: Nordin, Jakob
name: Goobar, Ariel
name: Jonsson, Jakob
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Observations of Type Ia supernovae used to map the expansion history of the Universe suffer from systematic uncertainties that need to be propagated into the estimates of cosmological parameters. We propose an iterative Monte-Carlo simulation and cosmology fitting technique (SMOCK) to investigate the impact of sources of error upon fits of the dark energy equation of state. This approach is especially useful to track the impact of non-Gaussian, correlated effects, e.g. reddening correction errors, brightness evolution of the supernovae, K-corrections, gravitational lensing, etc. While the tool is primarily aimed for studies and optimization of future instruments, we use the ``Gold'' data-set in Riess et al. (2007) to show examples of potential systematic uncertainties that could exceed the quoted statistical uncertainties.
description: Accepted for publication in JCAP
Resolved Hubble Space spectroscopy of ultracool binary systems
Creators: name: Martin, E. L.
name: Brandner, W.
name: Bouy, H.
name: Basri, G.
name: Davis, J.
name: Deshpande, R.
name: Montgomery, M.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Space Physics (physics.space-ph)
subject: FOS: Physical sciences

description: Using the low-resolution mode of the Space Telescope Imaging Spectrograph (STIS) aboard the \emph{Hubble Space Telescope} (HST), we have obtained spatially resolved spectra of 20 ultracool dwarfs. 18 of them belong to 9 known very low-mass binary systems with angular separations in the range 0.37-0.098 arcseconds. We have derived spectral types in the range dM7.5 to dL6 from the PC3 index, and by comparing our STIS spectra with ground-based spectra of similar spectral resolution from Mart{\'ı}n et al. (1999). We have searched for H$_α$ emission in each object but it was clearly detected in only 2 of them. We find that the distribution of H$_α$ emission in our sample is statistically different from that of single field dwarfs, suggesting an intriguing anticorrelation between chromospheric activity and binarity for M7--M9.5 dwarfs. We provide measuments of the strength of the main photospheric features and the PC3 index, and we derive calibrations of spectral subclasses versus F814W and K-band absolute magnitudes for a subset of 10 dwarfs in 5 binaries that have known trigonometric parallaxes.
description: accepted for publication in A&A
Collective Awareness for Abnormality Detection in Connected Autonomous Vehicles
Creators: name: Kanapram, Divya Thekke
name: Patrone, Fabio
name: Marin-Plaza, Pablo
name: Marchese, Mario
name: Bodanese, Eliane L.
name: Marcenaro, Lucio
name: Gómez, David Martín
name: Regazzoni, Carlo
Publisher: name: arXiv
Year: 2020
Subjects: subject: Machine Learning (cs.LG)
subject: Multiagent Systems (cs.MA)
subject: Signal Processing (eess.SP)
subject: FOS: Computer and information sciences
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: The advancements in connected and autonomous vehicles in these times demand the availability of tools providing the agents with the capability to be aware and predict their own states and context dynamics. This article presents a novel approach to develop an initial level of collective awareness in a network of intelligent agents. A specific collective self awareness functionality is considered, namely, agent centered detection of abnormal situations present in the environment around any agent in the network. Moreover, the agent should be capable of analyzing how such abnormalities can influence the future actions of each agent. Data driven dynamic Bayesian network (DBN) models learned from time series of sensory data recorded during the realization of tasks (agent network experiences) are here used for abnormality detection and prediction. A set of DBNs, each related to an agent, is used to allow the agents in the network to each synchronously aware possible abnormalities occurring when available models are used on a new instance of the task for which DBNs have been learned. A growing neural gas (GNG) algorithm is used to learn the node variables and conditional probabilities linking nodes in the DBN models; a Markov jump particle filter (MJPF) is employed for state estimation and abnormality detection in each agent using learned DBNs as filter parameters. Performance metrics are discussed to asses the algorithms reliability and accuracy. The impact is also evaluated by the communication channel used by the network to share the data sensed in a distributed way by each agent of the network. The IEEE 802.11p protocol standard has been considered for communication among agents. Real data sets are also used acquired by autonomous vehicles performing different tasks in a controlled environment.
description: IEEE Internet of Things Journal
X-ray verification of sol-gel resist shrinkage in substrate-conformal imprint lithography for a replicated blazed reflection grating
Creators: name: McCoy, Jake A.
name: Verschuuren, Marc A.
name: Miles, Drew M.
name: McEntaffer, Randall L.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Applied Physics (physics.app-ph)
subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: Surface-relief gratings fabricated through nanoimprint lithography (NIL) are prone to topographic distortion induced by resist shrinkage. Characterizing the impact of this effect on blazed diffraction efficiency is particularly important for applications in astrophysical spectroscopy at soft x-ray wavelengths ($λ\approx 0.5 - 5$~nm) that call for the mass-production of large-area grating replicas with sub-micron, sawtooth surface-relief profiles. A variant of NIL that lends itself well for this task is substrate-conformal imprint lithography (SCIL), which uses a flexible, composite stamp formed from a rigid master template to imprint nanoscale features in an inorganic resist that cures thermodynamically through a silica sol-gel process. While SCIL enables the production of several hundred imprints before stamp degradation and avoids many of the detriments associated with large-area imprinting in NIL, the sol-gel resist suffers shrinkage dependent on the post-imprint cure temperature. Through atomic force microscopy and diffraction-efficiency testing at beamline 6.3.2 of the Advanced Light Source, the impact of this effect on blaze response is constrained for a $\sim$160-nm-period grating replica cured at 90$^{\circ}$C. Results demonstrate a $\sim$2$^{\circ}$ reduction in blaze angle relative to the master grating, which was fabricated by anisotropic wet etching in $\langle 311 \rangle$-oriented silicon to yield a facet angle close to 30$^{\circ}$.
description: 17 pages, 11 figures
Hyperbolic Space Forms and Orbifold Compactification in M-Theory
Creators: name: Bytsenko, A. A.
name: Guimaraes, M. E. X.
name: Helayel-Neto, J. A.
Publisher: name: arXiv
Year: 2005
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We analyze solutions of string theory and supergravity which involve real hyperbolic spaces. Examples of string compactifications are given in terms of hyperbolic coset spaces of finite volume $Γ\backslash {\mathbb H}^N$, where $Γ$ is a discrete group of isometries of ${\mathbb H}^N$. We describe finite flux and the tensor kernel associated with hyperbolic spaces. The case of arithmetic geometry of $Γ= SL(2, {\mathbb Z}+i{\mathbb Z})/\{\pm Id\}$, where $Id$ is the identity matrix, is analyzed. We discuss supersymmetry surviving for supergravity solutions involving real hyperbolic space factors, string-supergravity correspondence and holography principle for a class of conformal field theories.
description: 11 pages. Work presented at the "Fourth International Winter Conference on Mathematical Methods in Physics", 09-13 August 2004, Rio de Janeiro, Brazil
Detection of Intermediate-Mass Black Holes in Globular Clusters Using Gravitational Lensing
Creators: name: Tatekawa, Takayuki
name: Okamura, Yuuki
Publisher: name: arXiv
Year: 2020
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: Recent observations suggest the presence of supermassive black holes at the centers of many galaxies. The existence of intermediate-mass black holes (IMBHs) in globular clusters has also been predicted. We focus on gravitational lensing as a new way to explore these entities. It is known that the mass distribution of a self-gravitating system such as a globular cluster changes greatly depending on the presence or absence of a central massive object. After considering possible mass distributions for a globular cluster belonging to the Milky Way galaxy, we estimate that the effect on the separation angle of gravitational lensing due to an IMBH would be of milliarcsecond order.
description: 17 pages, 13 figures
Learning from the Scatter in Type Ia Supernovae
Creators: name: Dodelson, Scott
name: Vallinotto, Alberto
Publisher: name: arXiv
Year: 2005
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Type Ia Supernovae are standard candles so their mean apparent magnitude has been exploited to learn about the redshift-distance relationship. Besides intrinsic scatter in this standard candle, additional source of scatter is caused by gravitational magnification by large scale structure. Here we probe the dependence of this dispersion on cosmological parameters and show that information about the amplitude of clustering, σ_8, is contained in the scatter. In principle, it will be possible to constrain σ_8 to within 5% with observations of 2000 Type Ia Supernovae. However, extracting this information requires subtlety as the distribution of magnifications is far from Gaussian. If one incorrectly assumes a Gaussian distribution, the estimate of the clustering amplitude will be biased three-σaway from the true value.
description: 4 pages, 3 figures
Quantifying COVID-19 enforced global changes in atmospheric pollutants using cloud computing based remote sensing
Creators: name: Singh, Manmeet
name: Singh, Bhupendra Bahadur
name: Singh, Raunaq
name: Upendra, Badimela
name: Kaur, Rupinder
name: Gill, Sukhpal Singh
name: Biswas, Mriganka Sekhar
Publisher: name: arXiv
Year: 2021
Subjects: subject: Atmospheric and Oceanic Physics (physics.ao-ph)
subject: FOS: Physical sciences

description: Global lockdowns in response to the COVID-19 pandemic have led to changes in the anthropogenic activities resulting in perceivable air quality improvements. Although several recent studies have analyzed these changes over different regions of the globe, these analyses have been constrained due to the usage of station-based data which is mostly limited upto the metropolitan cities. Also, the quantifiable changes have been reported only for the developed and developing regions leaving the poor economies (e.g. Africa) due to the shortage of in-situ data. Using a comprehensive set of high spatiotemporal resolution satellites and merged products of air pollutants, we analyze the air quality across the globe and quantify the improvement resulting from the suppressed anthropogenic activity during the lockdowns. In particular, we focus on megacities, capitals and cities with high standards of living to make the quantitative assessment. Our results offer valuable insights into the spatial distribution of changes in the air pollutants due to COVID-19 enforced lockdowns. Statistically significant reductions are observed over megacities with mean reduction by 19.74%, 7.38% and 49.9% in nitrogen dioxide (NO2), aerosol optical depth (AOD) and PM 2.5 concentrations. Google Earth Engine empowered cloud computing based remote sensing is used and the results provide a testbed for climate sensitivity experiments and validation of chemistry-climate models. Additionally, Google Earth Engine based apps have been developed to visualize the changes in a real-time fashion.
description: Preprint accepted in Remote Sensing Applications: Society and Environment
Xenon in Mercury-Manganese Stars
Creators: name: Dworetsky, M. M.
name: Persaud, J. L.
name: Patel, K.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Previous studies of elemental abundances in Mercury-Manganese (HgMn) stars have occasionally reported the presence of lines of the ionized rare noble gas Xe II, especially in a few of the hottest stars with Teff ~ 13000--15000 K. A new study of this element has been undertaken using observations from Lick Observatory's Hamilton Echelle Spectrograph. In this work, the spectrum synthesis program UCLSYN has been used to undertake abundance analysis assuming LTE. We find that in the Smith & Dworetsky sample of HgMn stars, Xe is vastly over-abundant in 21 of 22 HgMn stars studied, by factors of 3.1--4.8 dex. There does not appear to be a significant correlation of Xe abundance with Teff. A comparison sample of normal late B stars shows no sign of Xe II lines that could be detected, consistent with the expected weakness of lines at normal abundance. The main reason for the previous lack of widespread detection in HgMn stars is probably due to the strongest lines being at longer wavelengths than the photographic blue. The lines used in this work were 4603.03A, 4844.33A and 5292.22A.
description: 8 pages, 4 figures. Accepted by Monthly Notices of the Royal Astronomical Society, 8 January 2008
Anti-Stokes laser cooling in bulk Erbium-doped materials
Creators: name: Fernandez, Joaquin
name: Garcia-Adeva, Angel J.
name: Balda, R.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Other Condensed Matter (cond-mat.other)
subject: FOS: Physical sciences

description: We report the first observation of anti-Stokes laser-induced cooling in the Er^{3+}:KPb_{2}Cl_{5} crystal and in the Er^{3+}:CNBZn (CdF_{2}-CdCl_{2}-NaF-BaF_{2}-BaCl_{2}-ZnF_{2}) glass. The internal cooling efficiencies have been calculated by using photothermal deflection spectroscopy. Thermal scans acquired with an infrared thermal camera proved the bulk cooling capability of the studied samples. Implications of these results are discussed.
description: 4 pages, 4 figures. The figures enclosed with this submission are low quality ones. Versions of this paper with high quality figures are available upon request
A low level of extragalactic background light as revealed by gamma-rays from blazars
Creators: name: Collaboration, H. E. S. S.
name: :
name: Aharonian, F.
Publisher: name: arXiv
Year: 2005
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: The diffuse extragalactic background light consists of the sum of the starlight emitted by galaxies through the history of the Universe, and it could also have an important contribution from the first stars, which may have formed before galaxy formation began. Direct measurements are difficult and not yet conclusive, owing to the large uncertainties caused by the bright foreground emission associated with zodiacal light. An alternative approach is to study the absorption features imprinted on the gamma-ray spectra of distant extragalactic objects by interactions of those photons with the background light photons. Here we report the discovery of gamma-ray emission from the blazars H 2356-309 and 1ES 1101-232, at redshifts z=0.165 and z=0.186, respectively. Their unexpectedly hard spectra provide an upper limit on the background light at optical/near-infrared wavelengths that appears to be very close to the lower limit given by the integrated light of resolved galaxies. The background flux at these wavelengths accordingly seems to be strongly dominated by the direct starlight from galaxies, thus excluding a large contribution from other sources -- in particular from the first stars formed. This result also indicates that intergalactic space is more transparent to gamma-rays than previously thought.
description: 15 pages, 7 figures. Accepted by Nature, in press (April 20 issue). Replaced with published version. Title changed, text and figures rearranged with addition of Supplementary Information
Protein utilization, hormone treatment and nutrient metabolism as they apply to culture of abalone Haliotis kamtschatkana
Creators: name: Taylor, Barbara Elan
Publisher: name: University of British Columbia
Year: 2009

description: Development of formulated diets for use in abalone culture demands knowledge of the animal's nutritional requirements, growth, and metabolism. This thesis addresses some important aspects of these issues with regard to the abalone Haliotis kamtschatkana. Protein requirement was investigated from the standpoint of how protein utilization is affected by dietary protein content, amino acid balance, and protein sparing, together with the possible amelioration of the last through enzymatic adaptation to diet. Focus on protein utilization stems from the fact that protein is a costly dietary ingredient and is an essential nutrient for protein growth. With respect to abalone growth, I assessed the efficacy of administering vertebrate growth hormones which enhance growth in other cultured aquatic animals. I also investigated metabolism of cells isolated from the abalone digestive gland (a primary site of metabolic conversions) from the standpoints of seasonal variation in metabolic activity, and relationships between digestive gland and gonad activity during the reproductive cycle. My data show that optimal utilization of dietary protein in Haliotis kamtschatkana occurs when diets are formulated with about 20 % dry mass of protein, and with carbohydrates, rather than fats, comprising the energy source since enzymatic adaptation to diet does not alter protein-sparing effects. With respect to growth, I found no enhancement from treatment with recombinant bovine or porcine somatotropin, or somatostatin (vertebrate growth hormones). Furthermore, I found that metabolism in these animals is seasonal and possibly inter-related with the competitive needs of reproduction and somatic growth. These findings contribute to the general understanding of abalone biology and provide information useful for culture of abalone.
Experimental Quantum Error Rejection for Quantum Communication
Creators: name: Chen, Yu-Ao
name: Zhang, An-Ning
name: Zhao, Zhi
name: Zhou, Xiao-Qi
name: Pan, Jian-Wei
Publisher: name: arXiv
Year: 2005
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We report an experimental realization of bit-flip error rejection for error-free transfer of quantum information through a noisy quantum channel. In the experiment, an unknown state to be transmitted is encoded into a two-photon entangled state, which is then sent through an engineered noisy quantum channel. At the final stage, the unknown state is decoded by a quantum parity measurement, successfully rejecting the erroneous transmission over the noisy quantum channel.
description: 4 pages, 3 figures