Mexico and Nuestra tercera raíz : ideology, history identity and two towns of Veracruz

The thesis contributed to the growing body of knowledge and discourse on the African presence in Mexico. Long underresearched, Afromexican studies today command the attention of some of Mexico\u27s foremost historians and anthropologists. This thesis focused on some of their ideas and gave a general overview of the history of people of African descent in Mexico, particularly in the state of Veracruz, the port of entry for most of New Spain\u27s African slaves. Drawing on the work of these Afromexicanista scholars, this thesis demonstrated how their ideas intersect, and sometimes differ with, traditional scholarship in this neglected area. The elusive question of defining blackness within the national discourse of mestizaje formed part of the discussion. Mestizaje traditionally refers to the racial mixture of Europeans and indigenous Americans. Recent efforts seek to broaden the concept of mestizaje to include the descendants of Africans. Finally, this thesis reported on ethnographic fieldwork conducted in two Afromexican towns in Veracruz, Yanga and El Coyolillo, which have widely divergent attitudes toward the concept of blackness

Structure of neutron stars with unified equations of state

We present a set of three unified equations of states (EoSs) based on the nuclear energy-density functional (EDF) theory.These EoSs are based on generalized Skyrme forces fitted to essentially all experimental atomic mass data and constrained to reproduce various properties of infinite nuclear matter as obtained from many-body calculations using realistic two- and three-body interactions. The structure of cold isolated neutron stars is discussed in connection with some astrophysical observations.Comment: 4 pages, to appear in the proceedings of the ERPM conference, Zielona Gora, Poland, April 201

Symmetry energy: nuclear masses and neutron stars

We describe the main features of our most recent Hartree-Fock-Bogoliubov nuclear mass models, based on 16-parameter generalized Skyrme forces. They have been fitted to the data of the 2012 Atomic Mass Evaluation, and favour a value of 30 MeV for the symmetry coefficient J, the corresponding root-mean square deviation being 0.549 MeV. We find that this conclusion is compatible with measurements of neutron-skin thickness. By constraining the underlying interactions to fit various equations of state of neutron matter calculated {\it ab initio} our models are well adapted to a realistic and unified treatment of all regions of neutron stars. We use our models to calculate the composition, the equation of state, the mass-radius relation and the maximum mass. Comparison with observations of neutron stars again favours a value of J = 30 MeV.Comment: 10 pages, 9 figures, to appear in EPJA special volume on symmetry energ

Neutron drip transition in accreting and nonaccreting neutron star crusts

The neutron-drip transition in the dense matter constituting the interior of neutron stars generally refers to the appearance of unbound neutrons as the matter density reaches some threshold density $\rho_\textrm{drip}$. This transition has been mainly studied under the cold catalyzed matter hypothesis. However, this assumption is unrealistic for accreting neutron stars. After examining the physical processes that are thought to be allowed in both accreting and nonaccreting neutron stars, suitable conditions for the onset of neutron drip are derived and general analytical expressions for the neutron drip density and pressure are obtained. Moreover, we show that the neutron-drip transition occurs at lower density and pressure than those predicted within the mean-nucleus approximation. This transition is studied numerically for various initial composition of the ashes from X-ray bursts and superbursts using microscopic nuclear mass models.Comment: 24 pages, accepted for publication in Physical Review

Giant Pulsar Glitches and the Inertia of Neutron-Star Crusts

Giant pulsar frequency glitches as detected in the emblematic Vela pulsar have long been thought to be the manifestation of a neutron superfluid permeating the inner crust of a neutron star. However, this superfluid has been recently found to be entrained by the crust, and as a consequence it does not carry enough angular momentum to explain giant glitches. The extent to which pulsar-timing observations can be reconciled with the standard vortex-mediated glitch theory is studied considering the current uncertainties on dense-matter properties. To this end, the crustal moment of inertia of glitching pulsars is calculated employing a series of different unified dense-matter equations of state.Comment: 11 pages, 6 figures, submitted to PR

The dilemma of wildfire definition: what it reveals and what it implies

This paper presents the results of an explorative survey, based on a questionnaire sent by email, about how wildfire experts, operating in different countries, perceive wildfire and express their mindset by defining "wildfire" from a list of 14 terms and how they justify their preference for the term selected as the most important. Using a five-point Likert Scale, results from 221 valid replies indicate a general convergence toward a reduced number of terms. Six of them exhibit a mean >3.20 (Disturbance, Natural hazard, Climate-sensitive hazard, Socio-ecological hazard, Socio-ecological disturbance, and Social-ecological hazard). The three most preferred terms (i.e., Disturbance, Natural hazard, and Climate-sensitive hazard) reflect wildfire as a natural process or phenomenon (about 59% of the replies). The three terms characterized by both the social and ecological adjectives (i.e., Socio-ecological hazard, Socio-ecological disturbance, Social-ecological hazard) occupy relatively less favorable positions in the ranking. For each term, a synthesis of the explanations given by the respondents is provided, together with a critical comment. Our findings show very different perceptions of wildfires inclusively within the same disciplinary field. In addition, for the same term selected, different definitions are often presented. This reflects sectorial, disciplinary, and personal perspectives of the wildfire phenomenon and the lack of a common understanding of wildfire "nature" (i.e., its own identity). The different perceptions on wildfire concept influence the knowledge that can be used by decision makers to improve wildfire management policies. This work puts into perspective one of the most widespread problems in science: the lack of appropriate and similar terminology across different scientific fields dealing with the same problem. A common conceptualization of the nature of wildfires and the creation of a common language across different scientific fields related to wildfires is of paramount importance to address the complexity of the existing problems, and enhance an interactive communication not only among scientific community but also with stakeholders and citizens

The rising temperature trend and elongation of the warm period in summer in the Algerian South-West, 1951-2010

Several studies indicate that the hot season is lengthening at the expense of the intermediate seasons, and extreme events are becoming more intense and spread out over time. What is the situation in a climate described as very hot? This work aims to examine the evolution of minimum and maximum temperatures in the hot period from June to September during 1951-2010 in the Bechar region, which is classified among the hottest in the world and located in the south-west of Algeria. This study will also focus on the extending of the warm period (the period between the first and the last recording of an extremely hot day). The results showed an evolution of maximum and minimum temperatures, leading to an upward trend in the mid-1990s. There was an average increase of 1°C at the maximum and 0.9°C at the minimum. The warm period experienced a sig-nificant expansion attributed to both the earliest and the latest extremely hot day events

Comparative analysis of multisensor burned area products for the Brazilian Amazon - Region of the APA Triunfo do Xingu

Wildfires are not natural phenomena of the Amazon rainforest; therefore, they occur due to human activities, and their occurrences have increased in recent years. This situation requires continuous monitoring of this vast region, especially in areas where agricultural, livestock, mining, and infrastructure activities are located near protected areas (indigenous lands and nature conservation units). One of the conservation units that has recorded the highest increases in deforestation and fire rates is the Triunfo do Xingu Environmental Protection Area (APA Triunfo do Xingu), which since 2018 has registered the highest rates among other conservation units in the Amazon. The present study aims to develop two databases of burned areas from optical and microwave images for the years 2018, 2019, and 2020 for the APA Triunfo do Xingu using Google Earth Engine; then the results are compared with the DETER, MAPBIOMAS and MCD64A1 burned area bases to estimate existing similarities and divergences. This research uses the images of the Sentinel-2/S-2 and Landsat-8/L-8 optical satellites for the month of August of the years 2018, 2019, and 2020, a period of increased occurrences of active fires in the APA Triunfo do Xingu, to generate the burned area database that will serve as a reference for comparison with other burned area databases. Thus, images with spatial resolution, S-2 with 10 meters and L-8 with 30 meters and spectral (red, near, and medium infrared bands), are suitable for generating information with geometric and thematic quality, as the GEE allows the production of pixel mosaics excluding pixels with cloud and cloud shadows. The Sentinel-1/S-1 images used correspond to the VH cross-polarization, which is the most suitable polarization to map burned area than the VV polarization (Prasasti et al., 2020), having 10 meters of spatial resolution, being with speckle noise filter and with backscatter (DB) values. It is noteworthy that the S-1 images correspond to Band C, the wavelength of 5 cm, which reduces the interference of clouds when imaging the surface. In general, the BA-S1, BA-DETER, BA-MAPBIOMAS, and BA-MCD64A1 datasets obtained discrepant values concerning the reference dataset, which reveals that a consolidated base with values consistent with the reality of the fire regime of the study area is still to be achieved, as the discrepancies found reveal that the data and methodologies followed are not generating consistent quantitative information. Regarding the overlaps between the datasets, the spatial similarity between the datasets have a higher rate with polygons above 20 hectares, which allowed an average overlap of 63%, 69%, and 78% for the BA-S1, BA-MAPBIOMAS, and BA-MCD64A1. The BA-DETER dataset was below 20%, as it presents the lowest values of the number of polygons for the three years