Electron irradiation-induced defects for reliability improvement in monolayer MoS2-based conductive-point memory devices

Monolayer molybdenum disulfide has been previously discovered to exhibit non-volatile resistive switching behavior in a vertical metal-insulator-metal structure, featuring ultra-thin sub-nanometer active layer thickness. However, the reliability of these nascent 2D-based memory devices was not previously investigated for practical applications. Here, we employ an electron irradiation treatment on monolayer MoS2 film to modify the defect properties. Raman, photoluminescence, and X-ray photoelectron spectroscopy measurements have been performed to confirm the increasing amount of sulfur vacancies introduced by the e-beam irradiation process. The statistical electrical studies reveal the reliability can be improved by up to 1.5× for yield and 11× for average DC cycling endurance in the devices with a moderate radiation dose compared to unirradiated devices. Based on our previously proposed virtual conductive-point model with the metal ion substitution into sulfur vacancy, Monte Carlo simulations have been performed to illustrate the irradiation effect on device reliability, elucidating a clustering failure mechanism. This work provides an approach by electron irradiation to enhance the reliability of 2D memory devices and inspires further research in defect engineering to precisely control the switching properties for a wide range of applications from memory computing to radio- frequency switches.This work was supported in part by the National Science Foundation (NSF) grant #1809017, and an NSF MRSEC under Cooperative Agreement No. DMR-1720595. The authors acknowledge use of Texas Nanofabrication Facilities supported by the NSF NNCI award #1542159. D.A. acknowledges the Presidential Early Career Award for Scientists and Engineers (PECASE) through the Army Research Office (W911NF-16-1- 0277).Center for Dynamics and Control of Material

Sulfurization Engineering of One-Step Low-Temperature MoS2 and WS2 Thin Films for Memristor Device Applications

2D materials have been of considerable interest as new materials for device applications. Non-volatile resistive switching applications of MoS2 and WS2 have been previously demonstrated; however, these applications are dramatically limited by high temperatures and extended times needed for the large-area synthesis of 2D materials on crystalline substrates. The experimental results demonstrate a one-step sulfurization method to synthesize MoS2 and WS2 at 550 °C in 15 min on sapphire wafers. Furthermore, a large area transfer of the synthesized thin films to SiO2/Si substrates is achieved. Following this, MoS2 and WS2 memristors are fabricated that exhibit stable non-volatile switching and a satisfactory large on/off current ratio (103–105) with good uniformity. Tuning the sulfurization parameters (temperature and metal precursor thickness) is found to be a straightforward and effective strategy to improve the performance of the memristors. The demonstration of large-scale MoS2 and WS2 memristors with a one-step low-temperature sulfurization method with simple strategy to tuning can lead to potential applications such as flexible memory and neuromorphic computing.This research was primarily supported by the National Science Foundation through the Center for Dynamics and Control of Materials: an NSF MRSEC under Cooperative Agreement No. DMR-1720595. The work was partly done at the Texas Nanofabrication Facility supported by NSF grant NNCI-2025227. This work was performed in part at the Center for Integrated Nanotechnologies, an Office of Science User Facility operated for the U.S. Department of Energy (DOE) Office of Science. Los Alamos National Laboratory, an affirmative action equal opportunity employer, is managed by Triad National Security, LLC for the U.S. Department of Energy’s NNSA, under contract 89233218CNA000001.Center for Dynamics and Control of Material

A global experiment on motivating social distancing during the COVID-19 pandemic

Finding communication strategies that effectively motivate social distancing continues to be a global public health priority during the COVID-19 pandemic. This cross-country, preregistered experiment (n = 25,718 from 89 countries) tested hypotheses concerning generalizable positive and negative outcomes of social distancing messages that promoted personal agency and reflective choices (i.e., an autonomy-supportive message) or were restrictive and shaming (i.e., a controlling message) compared with no message at all. Results partially supported experimental hypotheses in that the controlling message increased controlled motivation (a poorly internalized form of motivation relying on shame, guilt, and fear of social consequences) relative to no message. On the other hand, the autonomy-supportive message lowered feelings of defiance compared with the controlling message, but the controlling message did not differ from receiving no message at all. Unexpectedly, messages did not influence autonomous motivation (a highly internalized form of motivation relying on one’s core values) or behavioral intentions. Results supported hypothesized associations between people’s existing autonomous and controlled motivations and self-reported behavioral intentions to engage in social distancing. Controlled motivation was associated with more defiance and less long-term behavioral intention to engage in social distancing, whereas autonomous motivation was associated with less defiance and more short- and long-term intentions to social distance. Overall, this work highlights the potential harm of using shaming and pressuring language in public health communication, with implications for the current and future global health challenges

A multi-country test of brief reappraisal interventions on emotions during the COVID-19 pandemic.

The COVID-19 pandemic has increased negative emotions and decreased positive emotions globally. Left unchecked, these emotional changes might have a wide array of adverse impacts. To reduce negative emotions and increase positive emotions, we tested the effectiveness of reappraisal, an emotion-regulation strategy that modifies how one thinks about a situation. Participants from 87 countries and regions (n = 21,644) were randomly assigned to one of two brief reappraisal interventions (reconstrual or repurposing) or one of two control conditions (active or passive). Results revealed that both reappraisal interventions (vesus both control conditions) consistently reduced negative emotions and increased positive emotions across different measures. Reconstrual and repurposing interventions had similar effects. Importantly, planned exploratory analyses indicated that reappraisal interventions did not reduce intentions to practice preventive health behaviours. The findings demonstrate the viability of creating scalable, low-cost interventions for use around the world

Integrating Agroecological Food Production, Ecological Restoration, Peasants’ Wellbeing, and Agri-Food Biocultural Heritage in Xochimilco, Mexico City

Chinampería, a jeopardized precolonial agricultural practice, persists in the Xochimilco wetland, Mexico City. Agroecological chinampa production is a recognized UNESCO World Heritage Site, and contributes to the sustainability of both the urban wetland and the city. The ‘chinampa-refuge’ model (CRM) is a transdisciplinary effort to strengthen traditional agroecological practices and ecological restoration. Through an inter/transdisciplinary research framework, we addressed the model’s role in the sustainability of this socio-ecosystem concerning four significant drivers of the wetland’s transformation. The CRM has improved water quality locally, increased the suitable habitat for native aquatic biodiversity, and supported traditional agroecological practices, thus improving the quality and safety of food products. However, there are clear challenges regarding production and commercialization, some of which may be addressed through the strengthening of the social organization and collective action. However, other challenges are beyond the reach of chinampa producers’ efforts and the CRM, but are decisive in changing the degradation trends. In order to address these challenges, urgent and participatory government actions are needed based on the recognition of the causes of wetland degradation and the role of traditional chinampa production in its sustainability

Estudios antropológicos e históricos. Num. 39 (2007) Vol. 14 enero-abril. Cuicuilco Revista de la Escuela Nacional de Antropología e Historia

- Presentación, por Patricia Fournier - Miscelánea: - Los mayos de Sinaloa: esbozo etnográfico y regional, por Hugo Eduardo López Aceves - Pesquerías y pescadores artesanales de camarón en el Cordón Estuárico, La Joya, La Barra y Buenavista, Chiapas. Territorio, organización y tecnología, por Carlos A. Gellida Esquinca y Reyna M. C. Moguel Viveros - Notas y reflexiones etnográficas en torno a la fauna y su relación con la región celeste del cosmos rarámuri, por Eduardo Rubén Saucedo Sánchez de Tagle - Percepción del ecosistema por la comunidad de San Crisanto en Yucatán de acuerdo con su actividad, por Gloria Chávez Ballado - La representación popular del maguey y el pulque en las artes, por Rodolfo Ramírez Rodríguez - “La calumnia es un arma, la mentira una fe”. Revolución y Cristiada: la batalla escrita del espíritu público, por Ana María Serna - Estructura del evento, tres sistemas de representación, por Martha Islas - Arqueología y educación. Estado de la cuestión, por Nantzín I. García Macías - Reseñas: - La población maya costera de Chac Mool: Análisis biocultural y dinámica demográfica en el Clásico Terminal y Posclásico, por Enrique Nalda - Perspectivas de la investigación arqueológica II. Homenaje a Gustavo Vargas Martínez, por Ernesto González Licón

In COVID-19 health messaging, loss framing increases anxiety with little-to-no concomitant benefits: Experimental evidence from 84 countries

The COVID-19 pandemic (and its aftermath) highlights a critical need to communicate health information effectively to the global public. Given that subtle differences in information framing can have meaningful effects on behavior, behavioral science research highlights a pressing question: Is it more effective to frame COVID-19 health messages in terms of potential losses (e.g., "If you do not practice these steps, you can endanger yourself and others") or potential gains (e.g., "If you practice these steps, you can protect yourself and others")? Collecting data in 48 languages from 15,929 participants in 84 countries, we experimentally tested the effects of message framing on COVID-19-related judgments, intentions, and feelings. Loss- (vs. gain-) framed messages increased self-reported anxiety among participants cross-nationally with little-to-no impact on policy attitudes, behavioral intentions, or information seeking relevant to pandemic risks. These results were consistent across 84 countries, three variations of the message framing wording, and 560 data processing and analytic choices. Thus, results provide an empirical answer to a global communication question and highlight the emotional toll of loss-framed messages. Critically, this work demonstrates the importance of considering unintended affective consequences when evaluating nudge-style interventions