Revista Jurídica Digital UANDES
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Bassey Wai Andah and archaeological thought
No full textDuring the final years of his career, Bassey Andah served as the President of the World Archaeological Congress. His election to this post was in part a recognition of the crucial role of advocacy and leadership that he had adopted during the traumatic emergence of that organization, in the context of the struggle against apartheid in South Africa (Ucko 1987: 241). However, it can also be seen as reflecting the extraordinary contribution that Andah had made in thinking through what it meant to be a practicing archaeologist in a non-First World setting. By the time that the present author came to work with him in the capacity of WAC Secretary, he had undergone a unique intellectual odyssey, as a consequence of having first absorbed Euro-American archaeological thinking, and subsequently having reflected upon it from the perspective of the post-colonial African experience. His political commitments provided him with a source of critique that he was able to turn upon the theories and methodologies that had been employed in African archaeology, developing a distinctive perspective that grew progressively more radical and more profound
Stable carbon isotope analysis on fossil Cedrus pollen shows summer aridification in Morocco during the last 5000 years
No full textQuantitative climate reconstructions from pollen typically rely on empirical relationships between pollen abundances or assemblages and climate, such as the modern analogue technique. However, these techniques may be problematic when applied to fossil sequences, as they cannot separate anthropogenic from climatic influence on pollen assemblages. Here, we reconstruct Mid- to Late-Holocene summer aridity in the Middle Atlas, Morocco, using stable carbon isotope analysis on isolated fossil Cedrus pollen. This approach is based on well documented plant physiological responses to moisture stress and is therefore independent from vegetation composition. We find that there has been a general long-term trend of increasing summer aridity in the region during the last 5000 years to the present day. The gradual decline of Cedrus atlantica forest in the Late-Holocene follows this aridity trend. Additionally, we show how isolating a specific pollen type for carbon isotope analysis yields a robust climate signal, versus using pollen concentrates or bulk sediment. Our findings indicate that climate has become drier in the region and confirms the Mid- to Late Holocene aridification trend observed more widely in the western Mediterranean, using a novel proxy for this region with good potential for wider application in other environments
Different definitions of atopic dermatitis: Impact on prevalence estimates and associated risk factors
No full textBackgroundThere is no objective test that can unequivocally confirm the diagnosis of atopic dermatitis (AD), and no uniform clinical definition.ObjectiveTo investigate to what extent operational definitions of AD cause fluctuation in the prevalence estimates and the associated risk factors.MethodsWe first reviewed operational definitions of AD used in the literature. We then tested the impact of the choice of the most common definitions of “Cases” and “Controls” on AD prevalence estimates and associated risk factors (including filaggrin‐FLG mutations) among children aged 5 years in two population‐based birth cohorts: Manchester Asthma and Allergy Study (MAAS) and Asthma in Ashford. Model performance was measured by the percentage of children within an area of clinical indecision (defined as having a posterior probability of AD between 25% and 60%).ResultsWe identified 59 different definitions of AD across 45 reviewed studies. Of those, we chose 4 common “Case” definitions, and 2 definitions of “Controls”. The prevalence estimates using different case definitions ranged between 22% and 33% in MAAS, and 12% and 22% in Ashford. The area of clinical indecision ranged from 32% to 44% in MAAS, and from 9% to 29% in Ashford. Depending on the case definition used, the associations with FLG mutations varied (ORs [95% CI]: 1.8 [1.1‐2.9] to 2.2 [1.3‐3.7] (MAAS) and 1.7 [0.8‐3.7] to 2.3 [1.2‐4.5] (Ashford)). Associations with FLG mutations also differed when using the same “Case” definition, but different definitions of “Controls”.ConclusionUse of different definitions of AD results in substantial difference in prevalence estimates, the performance of prediction models, and association with risk factors
Comedia y melancolía en la narrativa neopoliciaca (Vázquez Montalbán, Taibo II, Padura)
No full textIn recent years, both the intellectual lucidity of melancholy and the liberating potentials of comedy, irony and humour have emerged as central preoccupations in critical theory and literary criticism. In this book, Carlos van Tongeren offers a thorough and innovative reflection on the intersections between comedy and melancholy. Through detailed readings of almost twenty novels by three key writers of detective fiction in the Spanish-speaking world, he puts diverse melancholic attitudes towards the past and the multiple “surplus” values of comedy into a clear historical perspective. As such, this book provides a profound understanding of how comedy and melancholy have shaped Hispanic detective fiction following wider political and cultural developments in the post-totalitarian contexts of Spain, Mexico and Cuba.En años recientes, la lucidez intelectual de la melancolía y los potenciales liberadores de la comedia, la risa y el humor han emergido como preocupaciones centrales en la teoría crítica y crítica literaria. En este libro, Carlos van Tongeren ofrece una reflexión profunda e innovadora sobre las intersecciones entre la comedia y la melancolía. A través de una lectura detallada de una veintena de novelas de representantes clave de la ficción policiaca en el mundo hispanohablante, el autor muestra cómo la comedia y la melancolía han influido en la ficción policiaca en español, de acuerdo con cambios políticos y culturales más amplios en los contextos postotalitarios de España, México y Cuba
Achieving high performance Ga<sub>2</sub>O<sub>3</sub> diodes by adjusting chemical composition of tin oxide Schottky electrode
No full textHigh performance Ga2O3 Schottky barrier diodes (SBDs) are achieved by adjusting chemical composition of SnOx Schottky electrode. The SnOx is produced by radio frequency sputtering under various oxygen partial pressures (PO). A synergic study on Raman, X-ray photoelectron, and optical transmission spectroscopy of the SnOx films illustrates that: the films with PO = 0 ~ 3.1% consist mainly SnO and Sn with high conductivity; the films with PO = 4.6 ~ 5.4% are composed of both p-type SnO and n-type SnO2 with high resistance; the films with PO = 10.0 ~ 13.1% are mainly dominated by n-type SnO2 with low resistivity. In addition, as PO increased from 0 to 3.1%, the SBDs performances are significantly improved due to that the SnOdominated films reduce effectively the oxygen-deficiency at the Ga2O3 interfaces and the related interface state density. With PO = 5.4%, the high resistive SnOx results in degraded diode performance because that the SnO2 component with oxygen vacancy defects may aggravate the oxygen-deficiency at the Schottky interface. With the optimized PO of 3.1%, the SBD shows high performance with a large barrier height of 1.12 eV, a near unity ideality factor of 1.22, and a high rectification ratio of > 1010
Evidence of chemical heterogeneity within lunar anorthosite parental magmas
No full textLunar anorthosites are known for displaying a limited range of plagioclase An content (~An 94 to 98). Here we demonstrate that plagioclase trace-element variations from Apollo ferroan anorthosites (FAN) samples (collected by the Apollo 15 and 16 missions) display more significant chemical heterogeneity (e.g., chondrite-normalized [La/Sm] 0.33 to 5.42) than previously reported. We report mineral (plagioclase, pyroxene, and olivine) major- and trace element abundances for a suite of Apollo FAN samples, in addition to, anorthositic clasts within Apollo 16 regolith breccias. This suite of data extends the compositional range currently reported for Apollo anorthosites and for anorthositic clasts previously found within lunar meteorites. Petrological classifications of the regolith breccia clasts (e.g., anorthosite versus noritic anorthosites) cannot always be accurately assessed due to the limited size (< 1 cm) these rock fragments, however, the overlap in chemistry with the FAN suite highlights a genetic link with the FAN bedrock source. This observation emphasizes the usefulness of clasts and mineral fragments within regolith breccias, offering important insights into potentially unsampled bedrock lithologies from the Apollo 16 landing site. Melts in equilibrium with plagioclase can be used to assess parental melt compositions of the lunar magma ocean (LMO), from which anorthosites are generally agreed to have crystallized. In general, melts in equilibrium with the anorthosites reported here display slight light rare earth (LREE) depletions to LREE enrichments ([La/Sm]CI 0.87 to 2.5). The observed range of LREE enrichments from this suite, together with variations in ratios of other incompatible trace-elements (e.g., Th/Sm = 0.002 to 0.19) cannot be accounted for by fractional crystallization alone. We propose that the observed trace-element enriched anorthosites are related to overturn processes in the lunar mantle. During mantle overturn, the act of exhuming deep mafic-rich cumulates to the base of the lunar crust will trigger decompression melting. These are likely to be small degree (< 10%) partial melts, which are typically enriched in incompatible elements. Variable mixing between such melts, KREEP, and overlying plagioclase-saturated residual melts or plagioclase-rich lithologies will result in lunar anorthosites that display variable incompatible element enriched signatures. This is similar to the proposal of Floss et al. (1998) that suggested infiltration of local LMO magmas occurred by more evolved liquids through a process of metasomatism. By understanding the petrogenesis of these lunar anorthosites, we are able to constrain some of the complexities associated with the solidification of a magma ocean. This in turn, has important implications for understanding the timing and formation mechanisms of the Moon’s crust
A discriminatory test for the wheat B and G genomes reveals misclassified accessions of Triticum timopheevii and Triticum turgidum
No full textThe tetraploid wheat species Triticum turgidum and Triticum timopheevii are morphologically similar, and misidentification of material collected from the wild is possible. We compared published sequences for the Ppd-A1, Ppd-B1 and Ppd-G1 genes from multiple accessions of T. turgidum and T. timopheevii and devised a set of four polymerase chain reactions (PCRs), two specific for Ppd-B1 and two for Ppd-G1. We used these PCRs with 51 accessions of T. timopheevii and 20 of T. turgidum. Sixty of these accessions gave PCR products consistent with their taxon identifications, but the other eleven accessions gave anomalous results: ten accessions that were classified as T. turgidum were identified as T. timopheevii by the PCRs, and one T. timopheevii accession was typed as T. turgidum. We believe that these anomalies are not due to errors in the PCR tests because the results agree with a more comprehensive analysis of genome-wide single nucleotide polymorphisms, which similarly suggest that these eleven accessions have been misclassified. Our results therefore show that the accepted morphological tests for discrimination between T. turgidum and T. timopheevii might not be entirely robust, but that species identification can be made cheaply and quickly by PCRs directed at the Ppd-1 gen
The Use of a Sucrose Precursor to Prepare a Carbon Membrane for the Separation of Hydrogen from Methane
No full textIn this study, we present the use of sucrose (C12H22O11), which exists in abundance in nature, to prepare a carbon membrane without any preceding treatments. The preparation procedure was conducted using a low pyrolysis temperature, i.e., in the range of 300-500 ⁰C, followed by complete formation of the structure of the carbon membrane. The gas separation characteristics of the resulting membranes were assessed by evaluating both hydrogen and methane permeation. The highest selectivity obtained for H2/CH4 was 31.34 with H2 permeability of 459.24 GPU. The entire fabrication procedure was designed to be economical in order to facilitate any future commercialization
Herding in Smart-Beta Investment Products
No full textWe highlight herding of investors as one major risk factor that is typically ignored in statistical approaches to portfolio modelling and risk management. Our survey focuses on smart-beta investing where such methods and investor herding seem particularly relevant but its negative effects have not yet come to the fore. We point out promising and novel approaches of modelling herding risk which merit empirical analysis. This financial economists’ perspective supplements the vast statistical exploration of implementing factor strategies