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COCOA: A compact Compton camera for astrophysical observation of MeV-scale gamma rays
Get PDFCOCOA (COmpact COmpton cAmera) is a next-generation gamma-ray telescope designed for astrophysical observations in the MeV energy range. The detector comprises a scatterer volume employing the LiquidO detection technology and an array of scintillating crystals acting as absorber. Surrounding plastic scintillator panels serve as a veto system for charged particles. The detector’s compact, scalable design enables flexible deployment on microsatellites or high-altitude balloons. Gamma rays at MeV energies have not been well explored historically (the so-called “MeV gap”) and COCOA has the potential to improve the sensitivity in this energy band
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No full textUnderstory Forage Quality for Grazing Animals in Chilean Patagonian Forests
Get PDFNative forests provide forage for grazing animals. We investigated whether native and exotic vegetation promotes the potential animal load (PAL, ind ha−1 yr−1) for cattle (Bos taurus, ~700 kg) and sheep (Ovis aries, ~60 kg) in contrasting native forest types and canopy cover (closed, semi-open, open). This study was conducted in Chilean Patagonia (−44° to −49° SL). Vegetation cover (%) and growth habit data (trees, shrubs, forbs, graminoids, ferns, lianas, lichens, and bryophytes) were collected from 374 plots (>5 ha) in different environments: coihue (Nothofagus dombeyi, CO), lenga (N. pumilio, LE), mixed Nothofagus forests (MI), ñirre (N. antarctica, ÑI), evergreen forest (SV), and open land (OL). We combine this data with literature and laboratory analyses (e.g., crude protein, %) to develop PAL values for seasons. Data sampling was evaluated using descriptive analyses and uni- and multi-variate analyses (ANOVA, MCA, GLM). Results showed that closed forests had more native species (~56.6%) compared to open forests (~33.3%), while OL had higher cover of exotic species (~68.6%). LE presented the highest native species cover (~58.0%) and ÑI presented the highest exotic species cover (~53.0%). Closed forests had fewer exotic species than semi-open and open forests, which supported higher cover of native plants (p < 0.01). Forbs were the dominant growth habit in closed forests, while graminoids were dominant in OL (~45.8%). Multivariate analyses showed that LE and CO were associated with lower PAL values, explaining 91.2% variance. GLMs showed that the PAL increased in ÑI and the spring season, with forbs and graminoids having positive effects and shrubs and trees having negative effects (r2 = 0.57–0.67). Our analyses also showed that exotic species dominated environment types with a high PAL, particularly during spring and summer, when cover increased. This indicates a trade-off between forage production in forests with exotic plants
High‐quality epitaxial five‐layer aurivillius films with in‐plane ferroelectricity for electrocaloric cooling
Get PDFHigh‐quality purely c‐axis oriented epitaxial thin films of the Aurivillius phase Sr2Bi4Ti5O18 with n = 5 (Sr,Bi)TiO3 perovskite‐like layers, are grown on SrTiO3 substrates by pulsed laser deposition. The highest crystalline quality is obtained with a 20 wt.% Bi‐excess target and average stacking order values in the proximity of the ideal value n = 5 are attained for an optimum deposition temperature of 650 °C. Scanning transmission electron microscopy reveals regions with n ranging from 4 to 6 around an average thickness of n = 5, in agreement with the X‐ray diffraction analysis. Interdigital electrodes are used to probe the in‐plane polarization and survey the electrocaloric properties. A maximum adiabatic temperature change of ΔT ∼ 0.95 °C for an electric field of 150 kV cm−1 is observed at ≈135 °C. Larger values are expected at higher temperatures around the ferroelectric Curie temperature, TC. Since TC of Sr2Bi4Ti5O18 can be tuned by codoping, the findings pave the way toward a large electrocaloric effect at ambient temperature
La configuración del indio en los relatos ejemplares de la nueva España
Get PDFGran parte de los relatos presentes en los impresos novohispanos son de procedencia europea, sinembargo, otros tantos a los que denominamos «relatos de indios» se produjeron en el NuevoMundo, pues sus habitantes, su modo de vida y el contexto cultural, que en muchos sentidos eradiametralmente distinto al de la Península Ibérica, fueron una fuente inagotable de la quecronistas, predicadores y en general los escritores novohispanos, podían extraer ejemplos paraprobar o dar credibilidad a alguna determinada causa. La presente tesis trata sobre las formas enque se representó a los indios de la Nueva España en los ejemplos donde los indios tienenpresencia. Partiendo de un corpus de 123 relatos se analizan las múltiples representaciones delindio, logrando observar que dichas representaciones, por más diversas y contradictorias quellegaron a ser, terminaron como partes constitutivas de un mismo sujeto colectivo que, por unlado, podía cometer crímenes inimaginables y, por otro, exhibía una conducta intachable propiade un cristiano. A esta confluencia de representaciones dicotómicas es a lo que se llama«configuración» en esta investigación: un indio podía ser un cristiano ejemplar que era dado a laidolatría, o bien, podía mostrar dentro de su torpeza una gran iniciativa e inteligencia.El análisis propuesto se realiza desde una perspectiva retórica, entendiendo por relatosejemplares una de las formas en que se podía dar la prueba retórica. Bajo esta concepción se hapodido establecer que la forma en que los escritores presentan los ejemplos y la función quedesempeñan, es diferente dependiendo del autor o del tipo de impreso. Básicamente, laconclusión a la que se llega es que la configuración de los indios responde a dos cuestiones, porun lado, al interés de las órdenes religiosas de defender a los indios, pues consideraban que eltrato hacia ellos durante la conquista se contraponía con los mandatos bíblicos; a ello se debe quegran parte de las historias estén orientadas a mostrar sus virtudes morales, puesto que eso lesdaba pleno derecho a formar parte de la Iglesia. Por otro lado, la justificación del trato que se lesdaba, pues por medio de esas mismas órdenes se difundió en varios ejemplos la idea de que losnativos no eran plenamente humanos y eso impedía adherirlos a la Iglesia.<br /
El negocio de preservar el buen nombre. El sostén económico de la noble aragonesa Brianda de Luna tras su divorcio a fines del siglo XIV
Get PDFEl presente trabajo se centra en la gestión de la deuda de la aristócrata aragonesa Brianda de Luna, hermana de la reina María (1396-1406). Su huida con Luis Cornel desencadenó una guerra privada que socavó las finanzas de la pareja. Brianda y sus hijas recurrieron a un rescate financiero, la partición de deudas y la enajenación de señoríos. La imposibilidad de asumir con los ingresos disponibles los intereses de los préstamos a largo plazo condujo finalmente a la descapitalización del patrimonio familiar. La documentación conservada en los archivos notariales y nobiliarios ilumina la relación entre renta feudal, patrimonio y gestión de la deuda censal. Ello permite reflexionar sobre el papel del crédito en el seno de debates como la crisis de la nobleza y el ascenso de nuevos grupos sociales. En última instancia las elites mercantiles se beneficiarán de la transferencia de riqueza desde las comunidades vasallas de la nobleza acreedora.
This paper focuses on the debt management of the Aragonese aristocrat Brianda de Luna, sister of Queen Maria (1396-1406). Her elopement with Luis Cornel triggered a private war that undermined the couple's finances. Brianda and her daughters resorted to a financial rescue, a division of debts and the alienation of their estates. The incapacity to pay the interests of the long-term loans with the available income finally led to the decapitalisation of the family patrimony. The documentation preserved in the notarial and nobiliary archives sheds light on the relationship between feudal income, patrimony and the management of the annuities. This allows us to reflect on the role of credit in debates such as the crisis of the nobility and the rise of new social groups. Ultimately, the merchant elites would benefit from the transfer of wealth from the vassal communities of the creditor nobility
Comparative stakeholder perceptions of wildlife management in five European multi-use landscapes
Get PDFHuman-wildlife coexistence in shared landscapes requires effectively navigating different stakeholder interests. Despite progress in this field, most studies focus on a limited number of “problematic” wildlife species. This narrow scope overlooks the species-specific nature of human-wildlife interactions. To identify general patterns in stakeholder perceptions of diverse wildlife species, we implemented a modified 3i (interest, influence, impact) method to assess how individuals within seven stakeholder groups (crop farmers, livestock farmers, foresters, hunters, tourism operators, protected area managers, and staff of environmental non-governmental organizations) rated their interest in, their influence on, and how they are impacted by twelve wildlife species categories: moose, red deer, wild reindeer, chamois, roe deer, brown bear, wild boar, grey wolf, European ground squirrel, cormorant, eagles, and vultures (some of them were site-specific).
The study design consisted of two steps: 1) assessing expert perceptions of the 3i for each stakeholder-species combination in each of the five study areas in Bulgaria, Germany, Italy, Norway, and Spain, and 2) assessing stakeholder (251 individuals) perceptions of the 3i. We found substantial variation in stakeholder perceptions across groups, sites, and species categories. Within-group heterogeneity and individual respondents belonging to multiple stakeholder categories further challenged simplistic assumptions of distinct and well-defined stakeholder perspectives. Expert perceptions often underestimated stakeholder interest in wildlife species categories and occasionally diverged from stakeholder-perceptions of influence and impact. Notably, perceived impacts of brown bears, wolves, and eagles often exceeded the perceived influence on these species categories, underscoring a sense of powerlessness in managing interactions in some sites.
Our study provides a comparative framework for understanding major patterns in key conservation conflicts in Europe, and emphasizes the importance of addressing contextualized stakeholder diversity and heterogeneity for more effective co-management of human-wildlife coexistence. These findings offer actionable pathways for improving conservation outcomes and participatory wildlife management across Europe
Ensuring the Accuracy of CNN Accelerators Supplied at Ultra-Low Voltage
Get PDFUnderscaling the supply voltage (Vdd) to ultra-low levels below the safe-operation threshold voltage (Vmin) brings significant energy savings in digital CMOS circuits but introduces reliability challenges due to increased risk of bitcell permanent faults. This work explores the impact of such faults on the accuracy of a CNN inference accelerator supplying on-chip activation memories at ultra-low Vdd. By examining fault pat-terns, activation values, and memory usage, this paper proposes two microarchitectural techniques exploiting activation outliers and activation memory underutilization. These approaches are cost-effective, do not require programmer intervention, and are application-independent. Experimental results show that the proposed approaches maintain the original CNN accuracy and achieve energy savings by 2.1 % and 8.2 % compared to the state-of-the-art technique and a conventional accelerator supplied at Vmin, respectively, with a negligible impact on the system performance (less than 0.25 %)
Celdas solares duraderas y eficientes combinando perovskita y nanocristales
No full textEmerging photovoltaic (PV) technologies are being developed to improve the performance and the stability of solar cells. This thesis focused on the development of scalable and stable solar cells by assembling heterojunction devices. These devices combined perovskites (PK) with quantum dots (QDs) or bismuth-based nanocrystals (NCs). First, single junction solar cells with PK as active layers were fabricated and characterized under ambient conditions (no glove box) to offer a low cost and stable solution with high potential for large scale production. Two types of PV devices (spin coated and drop casted) were prepared using two modified MAPbI3 perovskite formulations (MAPbIxCl1-x and MA1-x(AVA)xPbI3) across planar (C-PSC) and mesoporous (M-PSC) configurations. The resulting maximum power conversion efficiencies (PCE) of the devices were 10.7% and 12.9% for drop casted and spin coated cells, respectively. Afterwards, the research continued with the synthesis and characterization of Bi2S3 NCs and their introduction into PV devices in combination with perovskite. However, the results were not the optimal, as the performance was not improved. On a different approach, CsPbBr3 QDs were synthesized by ligand-assisted room temperature processing and compared with commercial QDs produced with the traditional hot-injection method. The two materials had similar optical properties, but differed in their morphology and chemical environment. Different PV devices were fabricated via drop casting using various integration strategies, mixing QDs within the PK (MA1-x(AVA)xPbI3) layer, bilayer heterojunction or applying them on the outer glass surface. The performance obtained by coupling QDs (Q-PSC) with PK was better than PK alone (PSC), from 9.3% for control samples to 10.4% for samples with QDs, with an absolute PCE increase of 11.8%. Dedicated characterizations techniques were used for the analysis of layer modifications due to degradation. To further investigate the stability of these heterojunction devices, aging campaigns at damp heating (85°C/85% RH) conditions and light soaking (1 SUN) exposure were conducted. The study provided in-depth insights into degradation pathways and explored how QDs influence stability and long-term performance.<br /
Alfabetización mediática en salud: Una propuesta de análisis en estudiantes de enfermería
Get PDFIntroducción. La crisis sanitaria por COVID-19 evidenció un incremento de informaciones sanitarias en los medios, generando una infodemia que expuso la vulnerabilidad de la ciudadanía frente a la desinformación. Este hecho subraya la necesidad de la ciudadanía de consumir información de manera crítica y consciente. Ante esta realidad, la alfabetización mediática en salud busca capacitar a las personas para analizar críticamente información sanitaria. Sin embargo, carece de consenso sobre su medición y una insuficiente integración en la educación formal de los futuros profesionales de la salud, quienes deben ser referentes en esta competencia. Por ello, el objetivo de la Tesis Doctoral fue desarrollar una propuesta para el análisis y evaluación del nivel de alfabetización mediática en salud en estudiantes universitarios.Metodología. El estudio incluyó cuatro investigaciones. Primero, se analizó la producción, el consumo y los efectos de pódcast en España durante la pandemia mediante datos de iVoox y el Instituto Nacional de Estadística sobre mortalidad semanal entre 2020 y 2021 (Artículo I). Segundo, se realizó una revisión sistemática de los instrumentos de medición del nivel de alfabetización mediática en salud en población de 12 a 65 años y sus propiedades psicométricas (Artículo II). Tercero, se adaptó transculturalmente al español la escala MeHLit, validándola en un grupo de 80 estudiantes de Enfermería. Por último, se aplicó la escala adaptada (MeHLit-SV) a 416 estudiantes de Enfermería de cinco universidades españolas, analizando el nivel de AMS y su relación con variables sociodemográficas (Artículo IV).Resultados. El consumo de pódcast mostró una correlación positiva con la mortalidad por COVID-19 durante el preconfinamiento, el confinamiento y los primeros meses de 2021. La revisión sistemática identificó cuatro instrumentos destacados para medir la alfabetización mediática en salud, siendo MeHLit uno de los más robustos psicométricamente. Tras su adaptación al español, la MeHLit-SV constó de 21 ítems con altas propiedades psicométricas. Los estudiantes evaluados obtuvieron una puntuación media de 48,73, siendo más alta en quienes estudiaban en el centro-noreste de España (test ANOVA, p = 0,0002), residían en áreas urbanas (test ANOVA, p = 0,001), simultaneaban sus estudios con empleo (test ANOVA, p = 0,001) o vivían en núcleos menores a 500 habitantes (test ANOVA, p = 0,001).Conclusión. El pódcast emergió como un medio alternativo frente a la desinformación durante la pandemia. La alfabetización mediática en salud se presenta como respuesta académica y una competencia indispensable para el consumo crítico de información mediática sanitaria. Por ello, su medición y el análisis de los factores socioeconómicos permite establecer un punto de partida para mejorar las intervenciones de salud y los autocuidados de la ciudadanía.<br /