3,137 research outputs found
Early Cretaceous absolute geomagnetic paleointensities from Córdoba province (Argentina)
We present here new paleointensity and geochronology results from Early Cretaceous volcanic rocks of Sierra Chica de Cordoba (Argentina). The new K-Ar isotopic ages of 5 samples range from 136 to 122 Ma. Twenty five samples from 7 individual flows yielded acceptable paleointensity estimates. The mean paleointensity values per flow are ranging from 53.0±1.9 to 25.4±2.6 μT and the corresponding Virtual Dipole Moments (VDMs) are ranging from 9.3±1.3 to 4.6±0.5 (1022 Am2). This corresponds to the mean value of 7.3±1.7x1022 Am2, which is compatible to the present geomagnetic axial dipole. Currently available selected paleointensity data from 80 to 130 Ma suggest that geomagnetic field strength frequently fluctuated before and during the Cretaceous Normal Superchron while the magnetic polarity maintained stable. The mean paleointensities derived from Cordoba lavas agree remarkably well with those obtained from the Parana Magmatic Province (133-132 Ma). This reinforces the hypothesis about the unreliability of ‘Mesozoic Dipole Low'.Fil: Cejudo Ruiz, Ruben. Universidad Nacional Autónoma de México; MéxicoFil: Goguitchaichvili, Avto. Universidad Nacional Autónoma de México; MéxicoFil: Geuna, Silvana Evangelina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires; ArgentinaFil: Alva-Valdivia, Luis M.. Universidad Nacional Autónoma de México; MéxicoFil: Solé, Jesus. Universidad Nacional Autónoma de México; MéxicoFil: Morales, Juan. Universidad Nacional Autónoma de México; Méxic
Disentangling permanent and transitory monetary shocks with a nonlinear Taylor rule
This article provides an estimation method to decompose monetary policy innovations into persistent and transitory components using the nonlinear Taylor rule proposed in Andolfatto, Hendry, and Moran (2008) [Are inflation expectations rational? Journal of Monetary Economics, 55, 406–422]. To use the Kalman filter as the optimal signal extraction technique, we use a convenient reformulation for the state equation by allowing expectations to play a significant role in explaining the future time evolution of monetary shocks. This alternative formulation allows us to perform the maximum likelihood estimation for all the parameters involved in the monetary policy as well as to recover conditional probabilities of regime change. Empirical evidence on the US monetary policy making is provided for the period covering 1986-Q1 to 2021-Q2. We compare our empirical estimates with those obtained based on the particle filter. While both procedures lead to similar quantitative and qualitative findings, our approach has much less computational cost
Integration of a Canine Agent in a Wireless Sensor Network for Information Gathering in Search and Rescue Missions
Search and rescue operations in the context of emergency response to human or natural disasters have the major goal of finding potential victims in the shortest possible time. Multi-agent teams, which can include specialized human respondents, robots and canine units, complement the strengths and weaknesses of each agent, like all-terrain mobility or capability to locate human beings. However, efficient coordination of heterogeneous agents requires specific means to locate the agents, and to provide them with the information they require to complete their mission. The major contribution of this work is an application of Wireless Sensor Networks (WSN) to gather information from a multi-agent team and to make it available to the rest of the agents while keeping coverage. In particular, a canine agent has been equipped with a mobile node installed on a harness, providing information about the dog’s location as well as gas levels. The configuration of the mobile node allows for flexible arrangement of the system, being able to integrate static as well as mobile nodes. The gathered information is available at an external database, so that the rest of the agents and the control center can use it in real time. The proposed scheme has been tested in realistic scenarios during search and rescue exercises
Private Information and Endogenous Entry
We assume an organization made up of a principal and an agent in which the agent privately observes the state of nature. The agent can use his private information to set up a new firm (endogenous entry) with a positive fixed cost. We show that, in equilibrium, there is effective endogenous entry If the cost of entry the agent must bear to establish a new firm is low enough, as the agent has better information about the state of nature than the principal
Incorporación del proyecto mares a la gestión institucional y pedagógica de la institución educativa N° 56105 “Independencia Americana” de Yanaoca. Provincia de Canas. Cusco - 2020
La presente investigación tuvo como objetivo determinar el nivel de implementación del Proyecto MARES en la Institución Educativa de la Provincia de Canas y se desarrolló siguiendo un diseño no experimental - transeccional. Puesto que el planeta afronta numerosos problemas ambientales generados por la actividad humana, siendo el volumen de residuos sólidos y su inadecuada gestión uno de los de mayor importancia por sus consecuencias. Frente a estos problemas, la educación tiene el reto de encaminar hacia la mejor convivencia, restituyendo la comprensión del valor de la naturaleza. En esta perspectiva, el Ministerio de Educación viene implementando el proyecto de manejo de residuos sólidos “MARES”; habiéndose previsto que el proyecto MARES se implemente desde el año 2017. Los resultados proporcionados por los instrumentos de investigación, revelan que en la Institución Educativa N° 56105 “Independencia Americana” de Yanaoca. Provincia de Canas Cusco – 2019 no se han implementado el proyecto Mares, según las etapas e indicadores prescritos por el Ministerio de Educación. Si bien se implementaron acciones para optimizar la gestión de residuos sólidos, estas no corresponden a la implementación del proyecto de manejo residuos sólidos (MARES)
Second order phase transition in the six-dimensional Ising spin glass on a field
The very existence of a phase transition for spin glasses in an external
magnetic field is controversial, even in high dimensions. We carry out massive
simulations of the Ising spin-glass in a field, in six dimensions (which,
according to classical, but not generally accepted, field-theoretical studies,
is the upper critical dimension). We find a phase transition and compute the
critical exponents, that are found to be compatible with their mean-field
values. We also find that the replica-symmetric Hamiltonian describes the
scaling of the renormalized couplings near the phase transition.Comment: 16 pages, 11 figure
Assessment of regional pulmonary blood flow using Ga-68-DOTA PET
Background: In vivo determination of regional pulmonary blood flow (PBF) is a valuable tool for the evaluation of many lung diseases. In this study, the use of Ga-68-DOTA PET for the in vivo quantitative determination of regional PBF is proposed. This methodology was implemented and tested in healthy pigs and validated using fluorescent microspheres. The study was performed on young large white pigs (n = 4). To assess the reproducibility and consistency of the method, three PET scans were obtained for each animal. Each radiotracer injection was performed simultaneously to the injection of fluorescent microspheres. PBF images were generated applying a two-compartment exchange model over the dynamic PET images. PET and microspheres values were compared by regression analysis and Bland-Altman plot. Results: The capability of the proposed technique to produce 3D regional PBF images was demonstrated. The correlation evaluation between Ga-68-DOTA PET and microspheres showed a good and significant correlation (r = 0.74, P < 0.001). Conclusions: Assessment of PBF with the proposed technique allows combining the high quantitative accuracy of PET imaging with the use of Ga-68/Ge-68 generators. Thus, Ga-68-DOTA PET emerges as a potential inexpensive method for measuring PBF in clinical settings with an extended use.This work was supported by a grant from the Spanish Ministry of Economy and Competitiveness (MINECO) (SAF2014-58920-R) and a grant from the Carlos III Institute of Health (FIS-FEDER PI14-01427). C. Velasco is a recipient of a fellowship from the Spanish Ministry of Education (FPU014/01794). S. Espana and A. Santos are recipients of M+Vision Advanced fellowships from the community of Madrid. The CNIC is supported by the MINECO and the Pro CNIC Foundation, and is a Severo Ochoa Center of Excellence (MINECO award SEV-2015-0505).S
Phosphatidylcholine-coated iron oxide nanomicelles for in vivo prolonged circulation time with an antibiofouling protein corona
We report the synthesis of micellar phosphatidylcholine-coated superparamagnetic iron oxide nanoparticles as a new long circulation contrast agents for magnetic resonance imaging. Oleic acid-coated Fe3 O4 nanoparticles were first prepared through thermal degradation and then encapsulated into small clusters with a phosphatidylcholine coating to obtain hydrophilic nanomicelles. A thorough characterization confirmed the chemical nature of the coating and the excellent colloidal stability of these nanomicelles in aqueous media. Magnetization and relaxivity properties proved their suitability as magnetic resonance imaging (MRI) contrast agent and in vitro cell viability data showed low toxicity. Vascular lifetime and elimination kinetics in the liver were assessed by blood relaxometry and by in vivo MRI in rats and compared with "control" particles prepared with a polyethylene glycol derivative. These micellar particles had a lifetime in blood of more than 10 h, much longer than the control nanoparticles (≈2 h), which is remarkable considering that the coating molecule is a small biocompatible zwitterionic phospholipid. The protein corona was characterized after incubation with rat serum at different times by high-throughput proteomics, showing a higher proportion of bound apolipoproteins and other dysopsonins for the phosphatidylcholine particles. The antibiofouling properties of this corona and its resistance to the adsorption of proteins corroborate the observed enhanced stability and prolonged systemic circulation.This study is supported by a grant from FP7 Marie Curie, Pulmonary imaging network (PINET), by Fundacio La Maratode TV3 (70/C/2012) and by a grant from the Comunidad de Madrid (S2010/BMD-2326, Inmunothercan-CM) and by Spanish Economy Ministry (MAT2013-47303-P). We thank E. Urones (Centro Nacional de Microscopia de la Universidad Complutense de Madrid) for the transmission electronic microscopy imaging; P. Morales (Instituto de Ciencia de Materiales de la Universidad Autonoma de Madrid) for the thermogravimetric and magnetization analysis and B. Salinas (Fundacion Centro Nacional de Investigaciones Cardiovasculares and CIBER de Enfermedades Respiratorias) for the TEM picture of oleic acid coated Fe3 O4. The authors declare no competing financial interests.S
Handgun detection using combined human pose and weapon appearance
Closed-circuit television (CCTV) systems are essential nowadays to prevent
security threats or dangerous situations, in which early detection is crucial.
Novel deep learning-based methods have allowed to develop automatic weapon
detectors with promising results. However, these approaches are mainly based on
visual weapon appearance only. For handguns, body pose may be a useful cue,
especially in cases where the gun is barely visible. In this work, a novel
method is proposed to combine, in a single architecture, both weapon appearance
and human pose information. First, pose keypoints are estimated to extract hand
regions and generate binary pose images, which are the model inputs. Then, each
input is processed in different subnetworks and combined to produce the handgun
bounding box. Results obtained show that the combined model improves the
handgun detection state of the art, achieving from 4.23 to 18.9 AP points more
than the best previous approach.Comment: 17 pages, 18 figure
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