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Search Results: 1 - 10 of 11239 matches for " Daniela; Lopez "
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Optimal Distributed Searching in the Plane with and without Uncertainty
Alejandro Lopez-Ortiz,Daniela Maftuleac
Computer Science , 2014,
Abstract: We consider the problem of multiple agents or robots searching for a target in the plane. This is motivated by Search and Rescue operations (SAR) in the high seas which in the past were often performed with several vessels, and more recently by swarms of aerial drones and/or unmanned surface vessels. Coordinating such a search in an effective manner is a non trivial task. In this paper, we develop first an optimal strategy for searching with k robots starting from a common origin and moving at unit speed. We then apply the results from this model to more realistic scenarios such as differential search speeds, late arrival times to the search effort and low probability of detection under poor visibility conditions. We show that, surprisingly, the theoretical idealized model still governs the search with certain suitable minor adaptations.
Automatic Content Extraction on the Web with Intelligent Algorithms
Pablo Cababie,Alvaro Zweig,Gabriel Barrera,Daniela Lopez De Luise
Lecture Notes in Engineering and Computer Science , 2010,
An Autonomous Robot Prototype using Concept Learning Model
Gabriel M. Barrera,Juan J. Iglesias,Daniela Lopez de Luise
Lecture Notes in Engineering and Computer Science , 2010,
Coordinated Sumoylation and Ubiquitination Modulate EGF Induced EGR1 Expression and Stability
Arcangela Gabriella Manente, Giulia Pinton, Daniela Tavian, Gerardo Lopez-Rodas, Elisa Brunelli, Laura Moro
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0025676
Abstract: Background Human early growth response-1 (EGR1) is a member of the zing-finger family of transcription factors induced by a range of molecular and environmental stimuli including epidermal growth factor (EGF). In a recently published paper we demonstrated that integrin/EGFR cross-talk was required for Egr1 expression through activation of the Erk1/2 and PI3K/Akt/Forkhead pathways. EGR1 activity and stability can be influenced by many different post-translational modifications such as acetylation, phosphorylation, ubiquitination and the recently discovered sumoylation. The aim of this work was to assess the influence of sumoylation on EGF induced Egr1 expression and/or stability. Methods We modulated the expression of proteins involved in the sumoylation process in ECV304 cells by transient transfection and evaluated Egr1 expression in response to EGF treatment at mRNA and protein levels. Results We demonstrated that in ECV304 cells Egr1 was transiently induced upon EGF treatment and a fraction of the endogenous protein was sumoylated. Moreover, SUMO-1/Ubc9 over-expression stabilized EGF induced ERK1/2 phosphorylation and increased Egr1 gene transcription. Conversely, in SUMO-1/Ubc9 transfected cells, EGR1 protein levels were strongly reduced. Data obtained from protein expression and ubiquitination analysis, in the presence of the proteasome inhibitor MG132, suggested that upon EGF stimuli EGR1 sumoylation enhanced its turnover, increasing ubiquitination and proteasome mediated degradation. Conclusions Here we demonstrate that SUMO-1 modification improving EGR1 ubiquitination is involved in the modulation of its stability upon EGF mediated induction.
Smoke-free policy development in Italy through the legislative process of the ban 2000-2005, and press media review 1998-2008
Gorini,Giuseppe; Currie,Laura; Spizzichino,Lorenzo; Galeone,Daniela; Lopez,Maria J.;
Annali dell'Istituto Superiore di Sanità , 2011, DOI: 10.4415/ANN_11_03_04
Abstract: the objective of this article is to describe the process of approval of the italian smoking ban, enacted in 2005. the method is to conduct a review of proposed and approved legislation 20002005, and of articles published in italian newspapers, 1998-2008. enabling factors in the process were: the leadership of two consecutive health ministers, both physicians, who introduced the bill four times between 2000-2002; the repeated presentation and final approval of the bill as an amendment within a bill on public administration which enabled timely approval of the ban; and the stringent air quality standards in the 2003 regulation that made building smoking rooms impracticable and prohibitively expensive. limiting factors in the process were: the 6-month delay in approving the regulation on smoking rooms; the 1.5-year delay in approving the regulation establishing owners' responsibility for enforcing the ban in hospitality premises and the legal action in august 2005, which shifted responsibility for enforcement to police. eighty-three percent of the 808 articles published on smoking in 1998-2008 were released between 2000-2005, during the policy process. while the press devoted considerable attention to the issues raised by the hospitality sector, the long legislative process of the bill and its regulations also stimulated coverage on tobacco control issues.
A Criterion-based Genetic Algorithm Solution to the Jigsaw Puzzle NP-Complete Problem
Francisco Gindre,David A. Trejo Pizzo,Gabriel Barrera,M. Daniela Lopez De Luise
Lecture Notes in Engineering and Computer Science , 2010,
Using the X-ray Morphologies of Young Supernova Remnants to Constrain Explosion Type, Ejecta Distribution, and Chemical Mixing
Laura A. Lopez,Enrico Ramirez-Ruiz,Daniela Huppenkothen,Carles Badenes,David Pooley
Physics , 2010, DOI: 10.1088/0004-637X/732/2/114
Abstract: Supernova remnants (SNRs) are a complex class of sources, and their heterogeneous nature has hindered the characterization of their general observational properties. To overcome this challenge, we use statistical tools to analyze the Chandra X-ray images of Galactic and Large Magellanic Cloud SNRs. We apply two techniques, a power-ratio method (a multipole expansion) and wavelet-transform analysis, to measure the global and local morphological properties of the X-ray line and thermal emission in twenty-four SNRs. We find that Type Ia SNRs have statistically more spherical and mirror symmetric thermal X-ray emission than core-collapse (CC) SNRs. The ability to type SNRs based on thermal emission morphology alone enables, for the first time, the typing of SNRs with weak X-ray lines or with low-resolution spectra. We identify one source, SNR G344.7-0.1, as originating from a CC explosion that was previously unknown, and we confirm the tentative Type Ia classifications of G337.2-0.7 and G272.2-3.2. Although the global morphology is indicative of the explosion type, the relative morphology of the X-ray line emission within SNRs is not: all sources in our sample have well-mixed ejecta, irrespective of stellar origin. In particular, we find that 90% of the bright metal-line emitting substructures are spatially coincident and have similar scales, even if the metals arise from different burning processes. Moreover, the overall X-ray line morphologies within each SNR are the same, with <6% differences. These findings reinforce that hydrodynamical instabilities can efficiently mix ejecta in Type Ia and CC SNRs. The only exception is W49B, which is likely from its jet-driven/bipolar SN explosion. Finally, we describe observational constraints that can be used to test hydrodynamical models of SNR evolution; notably, the filling factor of X-ray emission decreases with SNR age.
Highly Parallel Acoustic Assembly of Microparticles into Well-Ordered Colloidal Crystallites
Crystal E. Owens,C. Wyatt Shields IV,Daniela F. Cruz,Patrick Charbonneau,Gabriel P. Lopez
Physics , 2015, DOI: 10.1039/C5SM02348C
Abstract: The precise arrangement of microscopic objects is critical to the development of functional materials and ornately patterned surfaces. Here, we present an acoustics-based method for the rapid arrangement of microscopic particles into organized and programmable architectures, which are periodically spaced within a square assembly chamber. This macroscale device employs two-dimensional bulk acoustic standing waves to propel particles along the base of the chamber toward pressure nodes or antinodes, depending on the acoustic contrast factor of the particle, and is capable of simultaneously creating thousands of size-limited, isotropic and anisotropic assemblies within minutes. We pair experiments with Brownian dynamics simulations to model the migration kinetics and assembly patterns of spherical microparticles. We use these insights to predict and subsequently validate the onset of buckling of the assemblies into three-dimensional clusters by experiments upon increasing the acoustic pressure amplitude and the particle concentration. The simulations are also used to inform our experiments for the assembly of non-spherical particles, which are then recovered via fluid evaporation and directly inspected by electron microscopy. This method for assembly of particles offers several notable advantages over other approaches (e.g., magnetics, electrokinetics and optical tweezing) including simplicity, speed and scalability and can also be used in concert with other such approaches for enhancing the types of assemblies achievable.
Modeling Agricultural Change through Logistic Regression and Cellular Automata: A Case Study on Shifting Cultivation  [PDF]
Santiago Lopez
Journal of Geographic Information System (JGIS) , 2014, DOI: 10.4236/jgis.2014.63021

Agricultural expansion is one of the prime driving forces of global land cover change. Despite the increasing attention to the factors that cause it, the patterns and processes associated with indigenous cultivation systems are not well understood. This study analyzes agricultural change associated with subsistence-based indigenous production systems in the lower Pastaza River Basin in the Ecuadorian Amazon through a spatially explicit dynamic model. The model integrates multiple logistic regression and cellular automata to simulate agricultural expansion at a resolution consistent with small scale agriculture and deal with inherently spatial processes. Data on land use and cultivation practices were collected through remote sensing and field visits, and processed within a geographic information system framework. Results show that the probability of an area of becoming agriculture increases with population pressure, in the vicinity of existing cultivation plots, and proximity to the center of human settlements. The positive association between proximity to cultivation areas and the probability of the presence of agriculture clearly shows the spillover effect and spatial inertia carried by shifting cultivation practices. The model depicts an ideal shifting cultivation system, with a complete cropping-fallow-cropping cycle that shows how agricultural areas expand and contract across space and over time. The model produced relatively accurate spatial outputs, as shown by the results of a spatial comparison between the simulated landscapes and the actual one. The study helped understand local landscape dynamics associated with shifting cultivation systems and their implications for land management.

Aquifer Vulnerability Assessment Methods: The Non-Independence of Parameters Problem  [PDF]
Daniela Ducci
Journal of Water Resource and Protection (JWARP) , 2010, DOI: 10.4236/jwarp.2010.24034
Abstract: This paper investigates the relationship between the two parameters, aquifer media and hydraulic conductiv-ity, and assesses their reliability for aquifer vulnerability assessment. To evaluate the possible non-inde-pendence of the parameters in question, sensitivity analysis procedure was used in a GIS environment. The procedure was tested in three areas where aquifer vulnerability was assessed, corresponding to three different hydrogeological settings. The applications demonstrate that non-independence is confirmed and is more evident in alluvial and volcano-pyroclastic aquifers.
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