From Economic Miracle to Developmental Basket Case: The Political Economy of Puerto Rico’s Operation Bootstrap

This study investigates why Operation Bootstrap, which once brought industrialization to Puerto Rico and was deemed successful, did not become a sustainable social and economic strategy. The study delves into how Puerto Rico\u27s colonial position affected this shift from success to failure. Although Operation Bootstrap initially prospered due to American funding and technological advancements, Puerto Rico\u27s colonial status ultimately impeded progress. A review of Puerto Rico\u27s history with the United States, including issues of debt and economic development, reveals that the island\u27s colonial past has made it challenging to address concerns related to economic advancement. This essay explores the relationship between the US and Puerto Rico since the Spanish-American War, the triumphs and setbacks of Operation Bootstrap, and how Puerto Rico\u27s colonial history hampered its economic growth. Additionally, it examines opposing viewpoints and underscores the significance of considering Puerto Rico\u27s colonial position when analyzing its struggles

The microscopic effect of intramolecular vibrational energy redistribution

We investigate the effect of inter-mode coupling on the vibrational relaxation dynamics of molecules in weak dissipative environments. The simulations are performed within the reduced density matrix formalism in the Markovian regime, assuming a Lindblad form for the system-bath interaction. The prototypical two-dimensional model system representing two CO molecules approaching a Cu(100) surface is adapted from an ab initio potential, while the diatom- diatom vibrational coupling strength is systematically varied. In the weak system-bath coupling limit and at low temperatures, only first order non- adiabatic uni-modal coupling terms contribute to surface-mediated vibrational relaxation. Since dissipative dynamics is non-unitary, the choice of representation will affect the evolution of the reduced density matrix. Two alternative representations for computing the relaxation rates and the associated operators are thus compared: the fully coupled spectral basis, and a factorizable ansatz. The former is well-established and serves as a benchmark for the solution of Liouville-von Neumann equation. In the latter, a contracted grid basis of potential-optimized discrete variable representation is tailored to incorporate most of the inter-mode coupling, while the Lindblad operators are represented as tensor products of one-dimensional operators, for consistency. This procedure results in a marked reduction of the grid size and in a much more advantageous scaling of the computational cost with respect to the increase of the dimensionality of the system. The factorizable method is found to provide an accurate description of the dissipative quantum dynamics of the model system, specifically of the time evolution of the state populations and of the probability density distribution of the molecular wave packet. The influence of intra-molecular vibrational energy redistribution appears to be properly taken into account by the new model on the whole range of coupling strengths. It demontrates that most of the mode mixing during relaxation is due to the potential part of the Hamiltonian and not to the coupling among relaxation operator

Textural development in sulfide-matrix ore breccias in the Aguablanca Ni-Cu deposit, Spain, revealed by X-ray fluorescence microscopy

The intrusion-hosted Ni-Cu sulfide deposit at Aguablanca in south-western Spain contains a high proportion of ores in the form of sulfide-matrix ore breccias. These are polymict, comprising autoliths and xenoliths in sulfide-rich and/or sulfide-poor matrices. Inclusion lithologies include calc-silicate skarn rocks from the adjacent marbles, ultramafic and mafic cumulates, and remelted and recrystallized mafic rocks containing spinifex-like textures. Breccia textures have been investigated at mm to cm scale using desk-top and synchrotron-based microbeam XRF mapping which reveal a number of distinctive common features: disaggregation of inclusions into adjacent sulfide along original silicate grain boundaries; complex reverse and oscillatory zoning in Cr content of clinopyroxene grains within sulfide and inside inclusions; narrow reaction rims between country rock clasts and enclosing silicates; and preferential disposition of pyroxene crystals within pyrrhotite-pentlandite aggregates (original MSS) relative to inclusion-poor chalcopyrite. The observed range of textures is explained by a model of percolation of molten sulfide through a pre-existing silicate-matrix intrusion breccia, preferentially displacing a cotectic or eutectic plagioclase-pyroxene melt. The process is analogous to that believed to have formed interspinifex ore in komatiite-hosted deposits, and also to that responsible for superficially similar sulfide matrix ore breccias at Voisey’s Bay. The preserved range of textures is interpreted as being due to late stage gravity-driven percolation of sulfide liquid from above into a pre-existing partially molten intrusion breccia. This intrusion breccia itself may have been emplaced into the neck of the Aguablanca stock, in the waning stages of magma flow

A dust disk surrounding the young A star HR4796A

We report the codiscovery of the spatially-resolved dust disk of the Vega-like star HR 4796A. Images of the thermal dust emission at $\lambda = 18 \mu$m show an elongated structure approximately 200 AU in diameter surrounding the central A0V star. The position angle of the disk, $30^{\circ} \pm 10^{\circ}$, is consistent to the position angle of the M companion star, $225^{\circ}$, suggesting that the disk-binary system is being seen nearly along its orbital plane. The surface brightness distribution of the disk is consistent with the presence of an inner disk hole of approximately 50 AU radius, as was originally suggested by Jura et al. on the basis of the infrared spectrum. HR 4796 is a unique system among the Vega-like or $\beta$ Pictoris stars in that the M star companion (a weak-emission T Tauri star) shows that the system is relatively young, $\sim 8 \pm 3$ Myr. The inner disk hole may provide evidence for coagulation of dust into larger bodies on a timescale similar to that suggested for planet formation in the solar system.Comment: 12 pages, 3 PostScript figures, accepted for publication in Astrophysical Journal Letter

Effect of environmental conditions and phenology in the dispersal of secondary Erysiphe necator conidia in a vineyard

An integrated powdery mildew management strategy to identify the principal moments of secondary Erysiphe necator conidia dispersal in a vineyard based on aerobiological, phenological and meteorological data was developed. An adaptation of the physiological P-days model was conducted to obtain a descriptive equation for the prediction of the advantageous meteorological conditions for Erysiphe necator conidia dispersal in the vineyards of the Ribeiro Designation of Origin area. Moreover, a regression model was developed to predict the conidia concentration as a function of the weather and aerobiological variables with the highest influence on airborne E. necator spores. Additionally, phenological observations were conducted during the vegetative cycle of Vitis vinifera, with the aim to identify the most susceptible phenological stages to powdery mildew infection by relating them with the detected atmospheric spore concentrations. The study was carried out from 2008 to 2018 in an experimental vineyard. The E. necator spores were trapped using a Lanzoni VPPS-2000 sampler and the phenological observations were conducted following the BBCH standardized scale. The highest total fungal spore amount per season in the atmosphere of the vineyard was detected in 2013 with 4828 spores m-3, while the lowest amount was recorded in 2009 with 883 spores m-3. In general, the highest daily airborne spore concentrations were detected during the Flowering (stage 6) or in the previous and next stages, whereas the maximum total spore amount by stage was recorded during Development of Fruits (stage 7). The proposed threshold of P-days for potential secondary infections in the Ribeiro D.O. ranges from 120 to 160 P-days. The combination of aerobiological, phenological and meteorological data provides us a useful tool for the knowledge of the Erysiphe necator conidia dispersal behaviour bringing agricultural practices closer to a sustainable system

Mid-infrared imaging of the young binary star Hen 3-600: Evidence for a dust disk around the primary

We present high-resolution mid-infrared observations of the nearby late-type young binary system Hen 3-600. The binary, at a distance of $\sim$ 50 pc, could be a member of the TW Hydrae Association, the nearest known group of young stars, with an age of a few million years. Our images make it possible for the first time to determine which star in the pair, separated by 1.4'', harbors the mid-infrared excess detected by IRAS. In the near-infrared, where the radiation is primarily photospheric, Hen 3-600A (M3) and Hen 3-600B (M3.5) have a flux ratio of 1.6. At 4.8$\mu$m, 10.8$\mu$m, and 18.2$\mu$m, the primary becomes increasingly dominant over the secondary, suggesting that most of the circumstellar dust in the system resides around Hen 3-600A. Comparison of the spectral energy distribution (SED) of Hen 3-600A to the median SED of classical T Tauri stars suggests that its disk may be truncated by the secondary and provides tentative evidence for a central disk hole. The distribution of dust in the Hen 3-600 system may provide important clues to the formation and evolution of protoplanetary disks in close binaries.Comment: 9 pages, 2 PostScript figures, accepted for publication in The Astrophysical Journal Letter