Commemorative Palimpsests in Post-Authoritarian Argentina: The Case of ESMA

The authoritarian military regime in Argentina (1976-1983) left lasting impacts on the country’s social, political, and economic way of life. Characterized by thousands of violations of human rights, this period in history is still felt in Argentine society as activists and families search for truth. Simultaneously, other actors prefer to deny responsibility and argue for the need to move on, thus renouncing the legacy of state terror. ESMA, a notorious former clandestine torture center in Buenos Aires, became a site of memory on March 24, 2004, a date that also came to symbolize the anniversary of the coup d’état. Using the case study of ESMA, my research into how four Argentine presidential administrations since 1989 have commemorated the anniversary of the dictatorship on March 24 will investigate the following issues: 1) How did political leaders influence the cultural prominence of ESMA? 2) As a physical reminder of past conflict, how have commemorative events at ESMA generated new rounds of conflict in each presidential term? By answering these questions, this paper will contribute to the understanding of how the initiatives of different political administrations shaped and will continue to influence Argentina’s search for closure amidst the commemoration of the country’s past

Precise Estimation of Cosmological Parameters Using a More Accurate Likelihood Function

The estimation of cosmological parameters from a given data set requires a construction of a likelihood function which, in general, has a complicated functional form. We adopt a Gaussian copula and constructed a copula likelihood function for the convergence power spectrum from a weak lensing survey. We show that the parameter estimation based on the Gaussian likelihood erroneously introduces a systematic shift in the confidence region, in particular for a parameter of the dark energy equation of state w. Thus, the copula likelihood should be used in future cosmological observations.Comment: 5 pages, 3 figures. Maches version published by the Physical Review Letter

Developmental design, fabrication, and test of acoustic suppressors for fans of high bypass turbofan engines

An analysis procedure was developed for design of acoustically treated nacelles for high bypass turbofan engines. The plan was applied to the conceptual design of a nacelle for the quiet engine typical of a 707/DC-8 airplane installation. The resultant design was modified to a test nacelle design for the NASA Lewis quiet fan. The acoustic design goal was a 10 db reduction in effective perceived fan noise levels during takoff and approach. Detailed nacelle designs were subsequently developed for both the quiet engine and the quiet fan. The acoustic design goal for each nacelle was 15 db reductions in perceived fan noise levels from the inlet and fan duct. Acoustically treated nacelles were fabricated for the quiet engine and quiet fan for testing. Performance of selected inlet and fan duct lining configurations was experimentally evaluated in a flow duct. Results of the tests show that the linings perform as designed

Asymptotic Conditional Distribution of Exceedance Counts: Fragility Index with Different Margins

Let $\bm X=(X_1,...,X_d)$ be a random vector, whose components are not necessarily independent nor are they required to have identical distribution functions $F_1,...,F_d$. Denote by $N_s$ the number of exceedances among $X_1,...,X_d$ above a high threshold $s$. The fragility index, defined by $FI=\lim_{s\nearrow}E(N_s\mid N_s>0)$ if this limit exists, measures the asymptotic stability of the stochastic system $\bm X$ as the threshold increases. The system is called stable if $FI=1$ and fragile otherwise. In this paper we show that the asymptotic conditional distribution of exceedance counts (ACDEC) $p_k=\lim_{s\nearrow}P(N_s=k\mid N_s>0)$, $1\le k\le d$, exists, if the copula of $\bm X$ is in the domain of attraction of a multivariate extreme value distribution, and if $\lim_{s\nearrow}(1-F_i(s))/(1-F_\kappa(s))=\gamma_i\in[0,\infty)$ exists for $1\le i\le d$ and some $\kappa\in{1,...,d}$. This enables the computation of the FI corresponding to $\bm X$ and of the extended FI as well as of the asymptotic distribution of the exceedance cluster length also in that case, where the components of $\bm X$ are not identically distributed

Hydrogen Evolution Reaction Measurements of Dealloyed Porous NiCu

Porous metals are of interest for their high surface area and potential for enhanced catalytic behavior. Electrodeposited NiCu thin films with a range of compositions were electrochemically dealloyed to selectively remove the Cu component. The film structure, composition, and reactivity of these samples were characterized both before and after the dealloying step using scanning electron microscopy, energy-dispersive spectroscopy, and electrochemical measurements. The catalytic behavior of the dealloyed porous Ni samples towards the hydrogen evolution reaction was measured and compared to that of the as-deposited samples. The dealloyed samples were generally more reactive than their as-deposited counterparts at low overpotentials, making the dealloying procedure a promising area of exploration for improved hydrogen evolution catalysts

Charge-localized p-phenylenedihydrazine radical cations: ESR and optical studies of intramolecular electron transfer rates

1,4-Bis(2-tert-butyl-2,3-diazabicyclo[2.2.2]oct-3-yl)benzene-1,4-diyl (2) its 2,5-dimethyl and 2,3,5,6-tetramethyl derivatives (3 and 4), their radical cations, and bis-radical dications are studied. Crystal structures including those of 2^+BPh_4^-, 3^(2+)(BPh_4^-)_2, 4^+BPh_4^-, and 4^(2+)(BPh_4^-)_2 establish that ring methylation causes more N-lone pair, aryl π twist without changing the NAr,NAr distance significantly and that both 2^+ and 4^+ have the charge localized in one hydrazine unit. NMR measurements show that 3^+ has about 6% of its spin at the four aryl CH and CMe carbons, while 4^+ has about 1.5% of its spin at the four CMe carbons. The average distance between the unpaired electrons of 3^(2+) and 4^(2+) was obtained from the dipolar splittings of their thermally excited triplet states and, as expected, is significantly smaller for 3^(2+) (5.25 Å) than for 4^(2+) (5.63 Å). Rate constants for electron transfer between the hydrazine units of 3^+ and 4^+ in CH_2Cl_2 and CH_3CN were determined by dynamic ESR. The intervalence radical cations show charge transfer bands corresponding to vertical electron transfer between the ground state and the highly vibrationally excited electron-shifted state, allowing calculation of the parameters controlling electron transfer. Electron transfer parameters obtained from the CT bands using adiabatic energy surfaces which approximate the CT band shapes observed produce rate constants within experimental error of those extrapolated to room temperature from the ESR data for both 3^+ and 4^+ in both solvents, without using tunneling corrections. The effects of mixing of the electronic wave functions of the reduced and oxidized hydrazine units of 2^+ on d_(NN), the C(t-Bu)N,NA(Ar) twist angle, and the aryl nitrogen lone pair, aryl π twist angle which are observed by X-ray are close to those predicted from the position of the minima on the ET coordinate X of the adiabatic energy surface calculated from the CT band

X-Ray Microanalysis of Ca and K in Corn Bran and Oat Hulls

Oat hulls and dry-milled corn bran were loaded with calcium or potassium and made into either sectioned bulk specimens of intact tissue embedded in resin or into non-sectioned bulk specimens made from powdered-compressed tissue formed into disks without resin. Regression lines of X-ray count versus mineral concentration were similar for both Ca and K. X-ray count versus mineral concentration relationships were similar for intact oat hulls and powdered-compressed specimens of either oat hulls or corn bran. However, the relationship for intact corn bran embedded in resin was significantly different. While the reason for this difference is not known, the result emphasizes the importance of using a proper calibration matrix to relate mineral concentration in biological material with X-ray count values. The standard error in slope of the regression lines, 0.07 and 0.08 for corn bran and oat hull, respectively, embedded in aged epoxy resin suggest that X-ray counts from these specimens allow one to estimate Ca or K concentration with a standard deviation of ± 10%. X-ray counts of Ca, K, and Cl in specimens embedded in epoxy resin decreased to stable values approximately four weeks after the resin was cured

Evolution of the Dependence of Residual Lifetimes

We investigate the dependence properties of a vector of residual lifetimes by means of the copula associated with the conditional distribution function. In particular, the evolution of positive dependence properties (like quadrant dependence and total positivity) are analyzed and expressions for the evolution of measures of association are given

An information theoretic approach to statistical dependence: copula information

We discuss the connection between information and copula theories by showing that a copula can be employed to decompose the information content of a multivariate distribution into marginal and dependence components, with the latter quantified by the mutual information. We define the information excess as a measure of deviation from a maximum entropy distribution. The idea of marginal invariant dependence measures is also discussed and used to show that empirical linear correlation underestimates the amplitude of the actual correlation in the case of non-Gaussian marginals. The mutual information is shown to provide an upper bound for the asymptotic empirical log-likelihood of a copula. An analytical expression for the information excess of T-copulas is provided, allowing for simple model identification within this family. We illustrate the framework in a financial data set.Comment: to appear in Europhysics Letter