Public Articles
Circuito RC
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Bayesian model comparison of alternative cosmologies
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In this work, we make a statistical comparison of some known cosmological models: The cosmological constant (ΛCDM) model, the constant equation-of-state (wCDM) model, the CPL dark energy parameterization, the Dvali-Gabadadze-Porrati (DGP) model, a vacuum-decay (Λ(t)CDM) model and also the power-law f(R) model in the metric formalism. For this purpose, we perform a Bayesian model selection analysis using the Affine-Invariant Ensemble Sampler Monte-Carlo method. In order to obtain the parametric space and the posterior distribution for the parameters of each model, we use the more up-to-date type Ia supernova (SNe Ia) data, the Joint Lightcurve Analysis (JLA) compilation, containing 740 events between 0.01 < z < 1.3. The model selection is then performed by obtaining the Bayesian evidence of each model and computing the Bayes factor between two models. The results indicate that the JLA data only cannot distinguish the standard ΛCDM from the Λ(t)CDM, power-law metric f(R) and DGP alternatives, but to make more strong conclusions, a more robust analysis including combining the SNe Ia data with other kind of observables is necessary.
All great truths begin as blasphemies: In Defense of "Silly" Research
The Sparse Analytic Hierarchy Process for large groups decision making
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Learning Authorea
The document record the basics HTML friendly LaTeX codes and shows some examples. It is for myself reference. I am learning authorea.
LaTeX is a programming language that can be used for writing documents. It is especially useful for the mathematics and sciences fields due to its ease of writing special symbols and equations while also making them look good. For those not using special characters LaTex requires minimal learning, making it a very approachable language. Most textbooks are actually written in LaTeX.
In this cheat sheet, we discuss some of the basics for writing documents in LaTeX. In particular, we will focus on web documents and introduce a subset of LaTeX which safely works on the web.
Structural Equation Modelling Tutorial
The proper care and feeding of your older graduate student.
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Ley de inducción de Faraday
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Is the Great Decoupling Real?
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Tejidos
Ley de inducción de Faraday
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Ley de Inducción de Faraday
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TP: Ley de Faraday parte II
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Ley de inducción de Faraday
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TP: Ley de Faraday
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Ley de Ohm y de Kirchoff
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Climate Physics Chapter 3: Radiation Balance
Nitrogen fertilization reduces wild berry production in boreal forests
Nitrogen is the main limiting nutrient in temperate and boreal forests. Large-scale nitrogen fertilization has been suggested as a potential tool to enhance production and meet the increasing demand for wood products and biofuels. Here, we test the effect of N fertilization and thinning on berry (i.e., fruit) production and incidence of fungal pathogens along a latitudinal gradient in Sweden. We used an N fertilization (100-150 kg ha-1) and thinning experiment that was established between 1970 and 1980 in 30 pine forests, covering a latitudinal gradient stretching from southern to northern Sweden. We measured fruit production and disease incidence of fungal pathogens in bilberry and cowberry in the experimental plots (30 x 30 m), over two years (2014 and 2015), when the stands were between 67-85 years old. Nitrogen fertilization reduced fruit production for both species, while thinning had a positive effect. For cowberry, treatment effects on fruit production were mainly associated with changes in plant cover, while direct treatment effects altered fruit production in bilberry. Furthermore, N application increased disease incidence of the parasitic fungus Valdensia heterodoxa in bilberry and contributed to the reduced fruit production in the N treatment. In contrast, disease incidence of the main parasitic fungus in cowberry (snow-blight disease) was negatively affected by N. Thinning decreased disease incidence in bilberry, but tended to increase incidence in cowberry. For cowberry, disease incidence increased with latitude. Overall, our results suggest that the N-induced effect on fruit production in bilberry is partly associated with presence of the parasitic fungus, and largely due to unknown direct effects. For cowberry, reduction in fruit production is correlated with N-induced negative effects on plant cover. Large-scale fertilization will have an overall negative impact on fruit production, and given that fruit production is considered highly valuable in the context of ecosystem services and functioning, this reduction should be considered when forest management scenarios that include N fertilization are evaluated. Thinning on the other hand, can promote fruit production and may be used as a management tool to generate berry-rich forests.
Highlights
Berry (i.e. fruit) production was measured in nitrogen (N) and thinning experiments
N fertilization reduced, but thinning increased, berry production
Changes in plant cover explained altered fruit production only for cowberry
Low fruit production in bilberry was correlated with incidence by a parasitic fungus
Keywords: fungi, latitude, nitrogen, silviculture, thinning, Vaccinium
Humanitarian OR
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locating+ allocation
Doyen et al. \cite{DoyenEtal2011} elaborate on necessity of pre- and post-disaster planning in humanitarian logistics for earthquakes. In their study, they consider a two-echelon logistics system, which facilitates the transshipment of the relief items to the demand points. In the top echelon, the relief items are stored in (uncapacitatd) regional rescue centers (RRCs) prior to the incident (e.g., an earthquake). Depending on the severity of the incident, which is realized through a set of probabilistic scenarios, the relief items are transmitted to (capacitated) local rescue centers (LRCs), where they are delivered to the demand points. Accordingly, the authors suggest a two-stage stochastic program for pre-positioning and post-distribution of the relief items. In the first stage, the location of the RRCs and their stock level is determined in pre-disaster phase. In the second stage, the decisions regarding the locations of the LRCs are made and the flows of relief items between echelons are determined. The model seeks minimization of facilities locating costs, inventory holding costs for RRCs, the necessary transportation costs, and the shortage costs. To solve this problem, the authors have developed a Lagrangian relaxation-based heuristics (LH) equipped with local search algorithm. To apply LH, the inter-relating constraints for the echelons are relaxed and lower and upper bounds are computed accordingly. Next, the solution technique performs iterative local search algorithm to improve the quality of the solution.
Quantifying long-term trophic state dynamics and drivers in Cultus Lake, British Columbia: A multi-proxy paleolimnological study
Passage des équations 32 à 45
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Equation 37 : $$\hat{\nabla}_{\mu} \rho^G = \sum_k \frac{k}{a} \chi^G Q_\mu^k$$ Equation 32 : $$\rho^G = \frac{1}{2}c_2 \dot{\phi}^2+...$$ Donc : $$\nmu \rho^G = c_2 \dot{\phi}\hat{\nabla}_\mu\dot{\phi}+...$$
How to understand the tunneling in attosecond experiment] How to understand the tunneling in attosecond experiment? Bohr-Einstein photon box Gedanken experiment, tunneling time and the wave particle duality
\label{sec:In} There is no doubt that the advent of ’attophysics’ opens new perspectives in the study of time resolved phenomena in atomic and molecular physics \cite{Corkum:2008,Maquet:2014,Gallmann:2012,Kling:2008,Scrinzi:2006}, the tunneling process and the tunneling time (T-time) in atoms and molecules \cite{Krausz:2009,Eckle:2008s,Eckle:2008,Landsman:2014II,Kullie:2015}. Attosecond science concerns primarily electronic motion and energy transport on atomic and molecular scales and is of fundamental interest to physics in general. The time-energy uncertainty relation (TEUR) receives a ‘new breath’ due to the actual problems of quantum information theory and impressive progress of the experimental technique in quantum optics and atomic physics \cite{Dodonov:2015,Maquet:2014}. In my previous work \cite{Kullie:2015}, I showed that using the TEUR (precisely that time and energy are conjugate variables) leads to a nice relation to determine the T-time in good agreement with the experimental finding in the attosecond experiment (for He atom) \cite{Landsman:2014II}, (1 attosecond = 10−18 second). The T-time and time itself in quantum mechanics (QM) are controversial, and there is still common opinion that time plays a role essentially different from the role of position in quantum mechanics (although it is not in line with special relativity, \cite{BauerM:2014}) and that time is a parameter, like a classical Newtonian time quantity, and hence does not obey an ordinary TEUR. Nevertheless, Hilgevoord concluded in his work \cite{Hilgevoord:2002} that when looking to a time operator a distinction must be made between the universal time coordinate t, a c-number like a space coordinate, and the dynamical time variable of a physical system situated in space-time; i.e. clocks. Accordingly in \cite{Kullie:2015,Kullie:2016} it was shown that the T-time is intrinsic, i.e. dynamically connected to the system (internal clock) after the classification of Busch \cite{Busch:1990I,Busch:1990II} and \cite{Muga:2008} (chap. 3). Fortunately, Bauer’s introduction of a self-adjoint dynamical time operator in Dirac’s relativistic quantum theory \cite{BauerM:2014,BauerM:2016}, supports the results of \cite{Kullie:2015}. In \cite{BauerM:2016,BauerM:2016I} Bauer concluded that the dynamical time operator provides a straightforward explanation (within standard relativistic quantum mechanics) of the T-times, which is measured in the photoionization experiments, compare the discussion in \cite{Kullie:2016}. In this respect, Bauer also rejects the claim of Dodonov \cite{Dodonov:2015} that no unambiguous and generally accepted results have been obtained for the time operator \cite{BauerM:2016,BauerM:2016p}. Moreover, Bauer showed \cite{BauerM:2016} that the Mandelstam-Tamm uncertainty associated with the observable $\hat{T}$ largely overestimates the internal time standard uncertainty as already discussed by Kullie \cite{Kullie:2016}. A similar controversial issue to the time issue (and the T-time and TEUR) is the wave-matter duality and the particulate nature of the light \cite{Lamb:1995,Zeilinger:2005}, since the Einstein hypothesis of the quanta as a carrier of hν based on the Planck hypothesis of the quantization of the energy E = hν. The term photon was given by G. N. Lewis in 1926 \cite{Lewis:1926}, and indeed the corpuscular hypothesis originally stems from Newton. As we will see in this work, the two issues closely appear in today’s attosecond experiments (ASEs). Indeed, since the appearance of QM time was controversial, the famous example is the Bohr-Einstein weighing photon box Gedanken experiment (BE-photon-box-GE). In \cite{Kullie:2015} I showed with a simple tunneling model that the tunneling in the attosecond experiment is intriguingly similar to the BE-photon-box-GE, where the former can be seen as a realization to the later, with the electron as a particle (instead of the photon) and an uncertainty in the energy being determined from the (Coulomb) atomic potential due to the electron being disturbed by the field F, instead of (the photon) being disturbed by the weighting process and, as a result, an uncertainty in the gravitational potential \cite{Aharonov:2000}, as shown by the famous proof of Bohr (see for example \cite{Auletta:2009} p. 132) to the uncertainty (or indeterminacy) of time in the BE-photon-box-GE \cite{Aharonov:2000,Busch:1990I,Busch:1990II}. The T-time and the tunneling process itself in the ASEs are hot debated, and the later is still rather unresolved puzzle. In the (low-frequency) ASEs the idea is to control the electronic motion by laser fields that are comparable in strength to the electric field in the atom. In today’s experiments usual intensities are ∼1014 Wcm−2, for more details we refer to the tutorial \cite{Calegari:2016,Dahlstrom:2012,Krausz:2009,Kling:2008,Scrinzi:2006}. In the majority of phenomena in attosecond physics, one can separate the dynamics into a domain “inside” the atom, where atomic forces dominate, and “outside”, where the laser force dominates, a two-step semi-classical model, pioneered by Corkum \cite{Corkum:1993}. Ionization as the transition from “inside” to “outside” of the atom plays a key role for attosecond phenomena. A key quantity is the Keldysh parameter \cite{Keldysh:1964}, \begin{equation}\label{gamK} \gamma_{_K} = \frac{\sqrt{2I_p}}{F} \omega_0=\tau_K\, \omega_0, \end{equation} where Ip denotes the ionization potential of the system (atom or molecule), ω0 is the central circular frequency of the laser pulse or the laser wave packet (LWP) and F, throughout this work, stands for the peak electric field strength at maximum, and τK denotes the Keldysh time. Hereafter in this work (unless it is clear), atomic units are used, where ℏ = m = e = 1, the Planck constant, the electron mass and the unit charge are all set to 1. At values γK > 1 one expects predominantly photo-ionization or multiphoton ionization (MPI), while at γK < 1 (field-)ionization happens by a tunneling process (for F < Fa), which means that the electron does not have enough energy to ionize directly, and therefore it tunnels (or tunnel-ionizes) through a barrier made by the Coulomb potential and the electric field of the laser pulse and escapes at the exit point to the continuum, as shown in fig [fig:ptc], see the following section. We pay attention to one important case study in attosecond physics, the T-time measurement in ASE performed by Keller \cite{Eckle:2008s,Eckle:2008,Landsman:2014II} and we will refer to it as the Keller ASE (KASE). In this experiment an elliptically polarized laser pulse is used with ω0 = 0.0619 au (λ = 736 nm), the ellipticity parameter ϵ = 0.87, while the electric field strengths are in the range F = 0.04 − 0.11 and for He atom Ip = 0.90357 au.