2,918 research outputs found
A measurement of the scale of homogeneity in the Early Universe
We present the first measurement of the homogeneity index, , a
fractal or Hausdorff dimension of the early Universe from the Planck CMB
temperature variations in the sky. This characterization of the
isotropy scale is model-free and purely geometrical, independent of the
amplitude of . We find evidence of homogeneity () for
scales larger than on the CMB sky.
This finding is at odds with the CDM prediction, which assumes a scale
invariant infinite universe. Such anomaly is consistent with the well known low
quadrupule amplitude in the angular spectrum, but quantified in a
direct and model independent way. We estimate the significance of our finding
for using a principal component analysis from the sampling
variations of the observed sky. This analysis is validated with an independent
theoretical prediction of the covariance matrix based purely on data. Assuming
translation invariance (and flat geometry ) we can convert the isotropy
scale into a (comoving) homogeneity scale of
, which is very close to the trapped surface
generated by the observed cosmological constant .Comment: 20 pages, 9 figure
Substance Abuse via Legally Prescribed Drugs: The Case of Vicodin in the United States
Vicodin is the most commonly prescribed pain reliever in the United States.
Research indicates that there are two million people who are currently abusing
Vicodin, and the majority of those who abuse Vicodin were initially exposed to
it via prescription. Our goal is to determine the most effective strategies for
reducing the overall population of Vicodin abusers. More specifically, we focus
on whether prevention methods aimed at educating doctors and patients on the
potential for drug abuse or treatment methods implemented after a person abuses
Vicodin will have a greater overall impact. We consider one linear and two
non-linear compartmental models in which medical users of Vicodin can
transition into the abuser compartment or leave the population by no longer
taking the drug. Once Vicodin abusers, people can transition into a treatment
compartment, with the possibility of leaving the population through successful
completion of treatment or of relapsing and re-entering the abusive
compartment. The linear model assumes no social interaction, while both
non-linear models consider interaction. One considers interaction with abusers
affecting the relapse rate, while the other assumes both this and an additional
interaction between the number of abusers and the number of new prescriptions.
Sensitivity analyses are conducted varying the rates of success of these
intervention methods measured by the parameters to determine which strategy has
the greatest impact on controlling the population of Vicodin abusers. From
these models and analyses, we determine that manipulating parameters tied to
prevention measures has a greater impact on reducing the population of abusers
than manipulating parameters associated with treatment. We also note that
increasing the rate at which abusers seek treatment affects the population of
abusers more than the success rate of treatment itself
Protocolo de trabalho para o haas next generation control
Dissertação de mestrado integrado em Engenharia Mecânica (área de especialização em Manufatura Avançada)Esta dissertação tem como objetivo decifrar todas as funcionalidades do novo controlador da Haas, o Next Generation Control, controladora que é utilizada para o controlo de processos de maquinagem utilizando máquinas CNC, ou seja, não a descrever, mas também informar o leitor acerca de todas as suas funcionalidades, enunciando os componentes principais e os diversos setores presentes no dispositivo. Para complementar este protocolo de trabalho, as informações teóricas culminarão numa componente prática de aplicação direta dos conhecimentos previamente adquiridos no desenvolvimento de um processo de maquinagem.
Inicialmente enquadra-se brevemente o leitor com informações acerca do passado das duas grandes áreas abordadas neste documento, a maquinagem CNC e a companhia “Haas Automations”, a conveniência destes tópicos incidem na maquinagem CNC ser o processo de produção utilizada na aplicação da controladora e a “Haas Automations” ser o fabricante do dito dispositivo. Em relação aos tópicos deste tipo de maquinagem tem-se diversas informações como os tipos de máquinas existentes, as etapas a considerar na preparação para este tipo de produção e ainda os tipos de operações mais comuns utilizando este método.
Uma análise detalhada da controladora em si também está incluída nesta dissertação onde, recorrendo a figuras informativas, é explicado a função de cada área de trabalho que está dividida em oito setores diferentes, ditas áreas que desempenham uma função importante e insubstituível na concretização desejada do processo geral de maquinagem. Consolida-se esta informação abordando o código geralmente utilizado na maquinagem CNC, o código-G, código este que será também estudado na componente prática devido a ser portador da informação acerca dos detalhes da operação (sequências de corte, detalhes de ferramentas, entre outros).
Por fim, é utilizado um exemplo prático com intuito de aplicar a informação obtida previamente num contexto real, onde são evidenciadas duas peças com características e modos de produção diferentes, para o manuseamento completo da controladora de modo a qualquer operador que siga os passos enunciados consiga completar com sucesso a produção.This dissertation aims to decipher all the functionalities of the new Haas controller, the Next Generation Control, a controller that is used for the control of machining processes using CNC machines, the goal is to not only describe, but also inform the reader of all its functionalities, listing its main components and the various sectors present in the device. To complement this work protocol, the theoretical information will culminate in a practical component of direct application from knowledge previously acquired about the development of a machining process.
To start with the reader is given information about the background of the two major areas addressed in this document, CNC machining and the company "Haas Automations", the convenience of these topics focus on CNC machining being the production process used in the application of the controller and "Haas Automations" being the manufacturer of this device. In relation to the topics of this type of machining, we have various information points, such as the type of existing machines, the steps to consider in the preparation for this type of production and also the most common types of operations whilst using this method.
A detailed analysis of the controller itself is also included in this dissertation, when using informative figures, the function of each work area is explained, and is divided into eight different sectors, such areas play an important and irreplaceable role in the desired achievement of the overall machining process. This information is consolidated by addressing the code generally used in CNC machining, the G-code, this code will also be studied in the practical component because it carries information about the details of operation (cutting sequences, tooling details, among others).
Finally, a practical example is used with the intention of applying the information previously obtained in a real life context, where two parts with different characteristics and production modes are shown, for the complete handling of the controller so that any operator who follows the stated steps can successfully complete the production
Echocardiography Core Laboratory Validation of a Novel Vendor-Independent Web-Based Software for the Assessment of Left Ventricular Global Longitudinal Strain
BACKGROUND: Global longitudinal strain (GLS) is an accurate and reproducible parameter of left ventricular (LV) systolic function which has shown meaningful prognostic value. Fast, user-friendly, and accurate tools are required for its widespread implementation. We aim to compare a novel web-based tool with two established algorithms for strain analysis and test its reproducibility. METHODS: Thirty echocardiographic datasets with focused LV acquisitions were analyzed using three different semi-automated endocardial GLS algorithms by two readers. Analyses were repeated by one reader for the purpose of intra-observer variability. CAAS Qardia (Pie Medical Imaging) was compared with 2DCPA and AutoLV (TomTec). RESULTS: Mean GLS values were −15.0 ± 3.5% from Qardia, −15.3 ± 4.0% from 2DCPA, and −15.2 ± 3.8% from AutoLV. Mean GLS between Qardia and 2DCPA were not statistically different (p = 0.359), with a bias of −0.3%, limits of agreement (LOA) of 3.7%, and an intraclass correlation coefficient (ICC) of 0.88. Mean GLS between Qardia and AutoLV were not statistically different (p = 0.637), with a bias of −0.2%, LOA of 3.4%, and an ICC of 0.89. The coefficient of variation (CV) for intra-observer variability was 4.4% for Qardia, 8.4% 2DCPA, and 7.7% AutoLV. The CV for inter-observer variability was 4.5%, 8.1%, and 8.0%, respectively. CONCLUSIONS: In echocardiographic datasets of good image quality analyzed at an independent core laboratory using a standardized annotation method, a novel web-based tool for GLS analysis showed consistent results when compared with two algorithms of an established platform. Moreover, inter- and intra-observer reproducibility results were excellent.</p
Régimen y distribución de los incendios forestales en el Estado de México (2000 a 2011)
Los incendios forestales propician cambios globales que afectan a la biósfera y se les considera la tercera causa en la pérdida y degradación de grandes extensiones de terrenos forestales; son una fuente significativa de las emisiones de gases que provocan el calentamiento global y la pérdida de millones de toneladas de carbono almacenado en los ecosistemas y otras repercusiones ambientales importantes. En los últimos años, el Estado de México ha ocupado los primeros lugares a nivel nacional en cuanto al número de ocurrencia de incendios. Este trabajo analiza el régimen de incendios forestales, los cuales están determinados por cambios en las variables del clima y el tipo de cobertura vegetal. Para ello, se revisó la base de datos diaria sobre climatología e incendios forestales generada por la Red Ambiental de Monitoreo Atmosférico y la Protectora de Bosques durante los años 2000 a 2011. Los resultados indican que la frecuencia anual fue de 1 418 incendios, que afectan en promedio una superficie de 5 141 hectáreas; con un Índice de afectación promedio de 3.3 hectáreas por incendio; que se presentan recurrentemente con una marcada estacionalidad en la temporada primavera verano, así como con un periodo de recurrencia de 1 o 2 años, en función de la precipitación, humedad y temperatura alcanzada el año anterior. En los ecosistemas de bosques templados y selvas ocurren los siniestros de alta severidad
Electrically switchable Casimir forces using transparent conductive oxides
Casimir forces between charge-neutral bodies originate from quantum vacuum
fluctuations of electromagnetic fields, which exhibit a critical dependence on
material's electromagnetic properties. Over the years, in-situ modulation of
material's optical properties has been enabled through various means and has
been widely exploited in a plethora of applications such as electro-optical
modulation, transient color generation, bio- or chemical sensing, etc. Yet
Casimir force modulation has been hindered by difficulty in achieving high
modulation signals due to the broadband nature of the Casimir interaction. Here
we propose and investigate two configurations that allow for in-situ modulation
of Casimir forces through electrical gating of a metal-insulator-semiconductor
(MIS) junction comprised of transparent conductive oxide (TCO) materials. By
switching the gate voltage on and off, a force modulation of > 400 pN is
predicted due to substantive charge carrier accumulation in the TCO layer,
which can be easily measured using state-of-the-art force measurement
techniques in an atomic force microscope (AFM). We further examine the
influence of the oxide layer thickness on the force modulation, suggesting the
importance of the fine control of the oxide layer deposition. Our work provides
a promising pathway for modulating the Casimir effect in-situ with
experimentally measurable force contrast
Engineering Casimir interactions with epsilon-near-zero materials
In this paper, we theoretically demonstrate the tunability of the Casimir force both in sign and magnitude
between parallel plates coated with dispersive materials. We show that this force, existing between uncharged
plates, can be tuned by carefully choosing the value of the plasma frequency (i.e., the epsilon-near-zero
frequency) of the coating in the neighborhood of the resonance frequency of the cavity. The coating layer
enables a continuous variation of the force between four limiting values when a coating is placed on each plate.
We explore the consequences of such variation when pairs of electric and magnetic conductors (i.e., low and
high impedance surfaces) are used as substrates on either side, showing that this continuous variation results
in changes in the sign of the force, leading to both stable and unstable conditions, which could find interesting
potential applications in nanomechanics, including nanoparticle tweezing.Defense Advanced Research Program Agency (DARPA) HR00112090084MCIN/AEI/10.13039/501100011033 PID2020-116739GB-I0
COMET: Clustering Observables Modelled by Emulated perturbation Theory
In this paper we present COMET, a Gaussian process emulator of the galaxy
power spectrum multipoles in redshift-space. The model predictions are based on
one-loop perturbation theory and we consider two alternative descriptions of
redshift-space distortions: one that performs a full expansion of the real- to
redshift-space mapping, as in recent effective field theory models, and another
that preserves the non-perturbative impact of small-scale velocities by means
of an effective damping function. The outputs of COMET can be obtained at
arbitrary redshifts (up to ), for arbitrary fiducial background
cosmologies, and for a large parameter space that covers the shape parameters
, , and , as well as the evolution parameters ,
, , , and . This flexibility does not impair COMET's
accuracy, since we exploit an exact degeneracy between the evolution parameters
that allows us to train the emulator on a significantly reduced parameter
space. While the predictions are sped up by at least two orders of magnitude,
validation tests reveal an accuracy of for the monopole and
quadrupole ( for the hexadecapole), or alternatively, better than
for all three multipoles in comparison to statistical
uncertainties expected for the Euclid survey with a tenfold increase in volume.
We show that these differences translate into shifts in mean posterior values
that are at most of the same size, meaning that COMET can be used with the same
confidence as the exact underlying models. COMET is a publicly available Python
package that also provides the tree-level bispectrum multipoles in
redshift-space and Gaussian covariance matrices.Comment: 18 pages, 10 figures; for the COMET Python package, see
https://gitlab.com/aegge/comet-em
Momento Económico (6)
Temas de hoy, 2/ Benjamín Retckiman Kirk:
Ambigüedad de los informes gubernamentales,
3/ ¿Magia de los números?, 6/ Arturo Ortíz
Wadgymar: El sector externo durante 1983, 7/
Saharí Angeles Cornejo: La política monetaria en
1983, 1O/ Carlos Morera: La política financiera
durante 1983, 13/ Bernardo Navarro B. y Jesús
Rodríguez L.: El transporte público, subsidio a las
mayorías o "realismo económico", 1
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