4,423 research outputs found
Pinched weights and Duality Violation in QCD Sum Rules: a critical analysis
We analyze the so-called pinched weights, that are generally thought to
reduce the violation of quark-hadron duality in Finite-Energy Sum Rules. After
showing how this is not true in general, we explain how to address this
question for the LR correlator and any particular pinched weight taking
advantage of our previous work [1], where the possible high-energy behavior of
the LR spectral function was studied. In particular we show that the use of
pinched weights allows to determine with high accuracy the dimension six and
eight contributions in the operator product expansion,
O6=(-4.3^[+0.9}_{-0.7})*10^-3 GeV^6 and O8=(-7.2^{+4.2}_{-5.3})*10^-3 GeV^8.Comment: 11 pages. A few references added and discussion slightly enlarged.
Results unchanged
Gravitational lensing by wave dark matter halos
Wave Dark Matter (WaveDM) has recently gained attention as a viable candidate
to account for the dark matter content of the Universe. In this paper we
explore the extent to which dark matter halos in this model, and under what
conditions, are able to reproduce strong lensing systems. First, we
analytically explore the lensing properties of the model -- finding that a pure
WaveDM density profile, a soliton profile, produces a weaker lensing effect
than other similar cored profiles. Then we analyze models with a soliton
embedded in an NFW profile, as has been found in numerical simulations of
structure formation. We use a benchmark model with a boson mass of
, for which we see that there is a bi-modality in the
contribution of the external NFW part of the profile, and actually some of the
free parameters associated with it are not well constrained. We find that for
configurations with boson masses -- , a range of
masses preferred by dwarf galaxy kinematics, the soliton profile alone can fit
the data but its size is incompatible with the luminous extent of the lens
galaxies. Likewise, boson masses of the order of , which
would be consistent with Lyman- constraints and consist of more compact
soliton configurations, necessarily require the NFW part in order to reproduce
the observed Einstein radii. We then conclude that lens systems impose a
conservative lower bound and that the NFW envelope around the
soliton must be present to satisfy the observational requirements.Comment: 26 pages, 7 figures, Publishe
Online Context-based Object Recognition for Mobile Robots
This work proposes a robotic object recognition
system that takes advantage of the contextual information latent
in human-like environments in an online fashion. To fully leverage
context, it is needed perceptual information from (at least) a
portion of the scene containing the objects of interest, which could
not be entirely covered by just an one-shot sensor observation.
Information from a larger portion of the scenario could still
be considered by progressively registering observations, but this
approach experiences difficulties under some circumstances, e.g.
limited and heavily demanded computational resources, dynamic
environments, etc. Instead of this, the proposed recognition
system relies on an anchoring process for the fast registration
and propagation of objects’ features and locations beyond the
current sensor frustum. In this way, the system builds a graphbased
world model containing the objects in the scenario (both
in the current and previously perceived shots), which is exploited
by a Probabilistic Graphical Model (PGM) in order to leverage
contextual information during recognition. We also propose a
novel way to include the outcome of local object recognition
methods in the PGM, which results in a decrease in the usually
high CRF learning complexity. A demonstration of our proposal
has been conducted employing a dataset captured by a mobile
robot from restaurant-like settings, showing promising results.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
The Assessment of Land Degradation and Desertification in Mexico: Mapping Regional Trend Indicators with Satellite Data
Understanding the patterns of land degradation and desertification to develop mitigation strategies requires identification of methods for accurate and spatially explicit assessment and monitoring. Remote sensing data offer the possibility to develop strategies that outline degradation and desertification. The free access policy on satellite imagery enables a new pathway to measure, assess, and monitor land degradation using indicators derived from multispectral satellite data. This chapter seeks to explore a methodology for land degradation and desertification assessment and monitoring, based on freely available multispectral satellite data. The method identifies net primary productivity (NPP) and canopy cover (CC) as indicators of degradation. The trajectories of these indicators show patterns and trends over time. The methodological development presented here is intended to be a tool for regional landscape monitoring and assessment, enabling the formulation of corrective action plans. This methodology was tested in a semi-deciduous ecosystem in the southeast of Mexico
On Managing Knowledge for MAPE-K Loops in Self-Adaptive Robotics Using a Graph-Based Runtime Model
Service robotics involves the design of robots that work in a dynamic and very open environment, usually shared with people. In this scenario, it is very difficult for decision-making processes to be completely closed at design time, and it is necessary to define a certain variability that will be closed at runtime. MAPE-K (Monitor–Analyze–Plan–Execute over a shared Knowledge) loops are a very popular scheme to address this real-time self-adaptation. As stated in their own definition, they include monitoring, analysis, planning, and execution modules, which interact through a knowledge model. As the problems to be solved by the robot can be very complex, it may be necessary for several MAPE loops to coexist simultaneously in the robotic software architecture endowed in the robot. The loops will then need to be coordinated, for which they can use the knowledge model, a representation that will include information about the environment and the robot, but also about the actions being executed. This paper describes the use of a graph-based representation, the Deep State Representation (DSR), as the knowledge component of the MAPE-K scheme applied in robotics. The DSR manages perceptions and actions, and allows for inter- and intra-coordination of MAPE-K loops. The graph is updated at runtime, representing symbolic and geometric information. The scheme has been successfully applied in a retail intralogistics scenario, where a pallet truck robot has to manage roll containers for satisfying requests from human pickers working in the warehousePartial funding for open access charge: Universidad de Málaga. This work has been partially developed within SA3IR (an experiment funded by EU H2020 ESMERA Project under Grant Agreement 780265), the project RTI2018-099522-B-C4X, funded by the Gobierno de España and FEDER funds, and the B1-2021_26 project, funded by the University of Málaga
Individualized exercises for continuous assessment in engineering
This project focuses on the development of a web application that automatically grades the solution to engineering exercises. The input data of each exercise is different for each student in order to reduce plagiarism and increase motivation. Students can access the web app from any device with internet access (computer, laptop, phone, …) at any time. The fact that the exercises are enunciated and evaluated in an individualized way eliminates the possibility for students to share the solutions and divert the profitable collaboration between students towards the learning of the resolution procedure itself. From the professor’s perspective, this tool allows an efficient and continuous evaluation of students. Besides, the storage of the data (number of attempts, time required, etc.) provides valuable information both for the self-assessment of the professor and for the analysis of the individualized learning process of each student. The web application is coded in Python, which easily allows the incorporation of additional features according to the needs of professors and students. The web application has already been tested during two academic years in two Spanish universities and for several engineering degrees. Ten professor and more than 2000 students have already benefit from this web application.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
Daily sitting for long periods increases the odds for subclinical atheroma plaques
Sedentarism is a risk factor for cardiovascular disease (CVD), but currently it is not clear how a sedentary behavior such as long sitting time can affect atherosclerosis development. This study examined the relationship between sitting time and the prevalence of carotid and femoral subclinical atherosclerosis. A cross-sectional analysis based on a subsample of 2082 participants belonging to the Aragon Workers’ Health Study was carried out. Ultrasonography was used to assess the presence of plaques in carotid and femoral territories; the validated Spanish version of the questionnaire on the frequency of engaging in physical activity used in the Nurses’ Health Study and the Health Professionals’ was used to assess physical activity and sitting time; and demographic, anthropometric, and clinical data were obtained by trained personnel during the annual medical examination. Participants were categorized into <9 h/day and ≥9 h/day sitting time groups. After adjusting for several confounders, compared with participants that remain seated <9 h/day, those participants who remain seated ≥9 h/day had, respectively, OR = 1.25 (95%CI: 1.01, 1.55, p < 0.05) and OR = 1.38 (95%CI: 1.09, 1.74, p < 0.05) for carotid and any-territory plaque presence. Remaining seated ≥9 h/day is associated with higher odds for carotid and any-territory plaque presence independently of physical activity levels and other cardiovascular risk factors
Urea-based fertilization strategies to reduce yield-scaled N oxides and enhance bread-making quality in a rainfed Mediterranean wheat crop
Small vessel microembolization and acute glomerulonephritis following infection of aesthetic filler implants
Background: The systemic consequences of esthetic filler injections are poorly understood. Case presentation: We report a patient with a past history of subcutaneous injection of aesthetic filler material in the lower legs, who presented with post-infectious glomerulonephritis following necrotic leg ulcers at the injection site. Kidney biopsy revealed the presence of translucent, non-birefringent microspherical bodies compatible with polymethylmetacrylate (PMMA) microspheres in some capillary lumens. This had not previously been described. PMMA is a biphasic aesthetical filler composed of polymethylmetacrylate microspheres suspended in a biodegradable bovine collagen carrier. The solid phase (PMMA microspheres) persists in tissues for years. Although PMMA was thought to not disseminate systemically, tissue necrosis may have favored systemic dissemination of the microspheres, although entry in the circulation and microembolization at the time of administration cannot be ruled out. Conclusions: In conclusion, aesthetic filler implants may cause microembolization into small vessels. Recognition of the characteristic morphology may expedite diagnosis and avoid unnecessary further testing.AO and CMC were supported by ISCIII and FEDER funds PI13/00047, REDinREN RD012/0021, Comunidad de Madrid CIFRA S2010/BMD-2378 and Programa Intensificación Actividad Investigadora. BFF by ISCIII Joan Rodes
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