132 research outputs found

    A Hypothesis Guaranteeing the Weak Weak Axiom

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    The Weak Weak Axiom (WWA) for the aggregate excess demand function ensures uniqueness of equilibrium in regular economies. Jerison (1999) shows that the WWA holds if the excess demand satisfies the hypothesis of Nondecreasing Dispersion of Excess Demand (NDED). This note offers a new hypothesis guaranteeing that the WWA holds and suggests a new way for obtaining supporting empirical evidence

    Phase Stability and Fast Ion Conductivity in the Hexagonal LiBH4-LiBr-LiCl Solid Solution

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    This study shows a flexible system that offers promising candidates for Li-based solid-state electrolytes. The Br− substitution for BH4 − stabilizes the hexagonal structure of LiBH4 at room temperature (RT), whereas Cl− is soluble only at higher temperatures. Incorporation of chloride in a hexagonal solid solution leads to an increase in the energy density of the system. For the first time, a stable hexagonal solid solution of LiBH4 containing both Cl− and Br-halide anions has been obtained at RT. The LiBH4−LiBr−LiCl ternary phase diagram has been determined at RT by X-ray diffraction coupled with a Rietveld refinement. A solubility of up to 30% of Cl− in the solid solution has been established. The effect of halogenation on the Li-ion conductivity and electrochemical stability has been investigated by electrochemical impedance spectroscopy and cyclic voltammetry. Considering the ternary samples, h-Li(BH4)0.7(Br)0.2(Cl)0.1 composition showed the highest value for conductivity (1.3 × 10−5 S/cm at 30 °C), which is about 3 orders of magnitude higher than that for pure LiBH4 in the orthorhombic structure. The values of Li-ion conductivity at RT depend only on the BH4 − content in the solid solution, suggesting that the Br/Cl ratio does not affect the defect formation energy in the structure. Chloride anion substitution in the hexagonal structure increases the activation energy, moving from about 0.45 eV for samples without Cl− ions in the structure up to about 0.63 eV for h-Li(BH4)0.6(Br)0.2(Cl)0.2 compositions, according to the Meyer−Neldel rule. In addition to increasing Li-ion conductivity, the halogenation also increases the thermal stability of the system. Unlike for the Liion conductivity, the Br/Cl ratio influences the electrochemical stability: a wide oxidative window of 4.04 V versus Li+/Li is reached in the Li−Br system while further addition of Cl is a trade-off between oxidative stability and weight reduction. The halogenation allows both binary and ternary systems operating below 120 °C, thus suggesting possible applications of these fast ion conductors as solid-state electrolytes in Li-ion batteries

    Diagnostic performance of endoscopic ultrasound-guided tissue acquisition of splenic lesions: systematic review with pooled analysis

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    Background: Focal splenic lesions are usually incidentally discovered on radiological assessments. Although percutaneous tissue acquisition (TA) under trans-abdominal ultrasound guidance is a well-established technique for obtaining cyto-histological diagnosis of focal splenic lesions, endoscopic ultrasound (EUS)-guided TA has been described in several studies, reporting different safety and outcomes. The aim was to assess the pooled safety, adequacy, and accuracy of EUS-TA of splenic lesions. Methods: A comprehensive review of available evidence was conducted at the end of November 2021. All studies including more than five patients and reporting about the safety, adequacy, and accuracy of EUS-TA of the spleen were included. Results: Six studies (62 patients) were identified; all studies have been conducted using fine-needle aspiration (FNA) needles. Pooled specimen adequacy and accuracy of EUS-TA for spleen characterization were 92.8% [95% confidence interval (CI), 86.3%-99.3%] and 88.2% (95% CI, 79.3%-97.1%), respectively. The pooled incidence of adverse events (six studies, 62 patients) was 4.7% (95% CI, 0.4%-9.7%). Conclusion: EUS-FNA of the spleen is a safe technique with high diagnostic adequacy and accuracy. The EUS-guided approach could be considered a valid alternative to the percutaneous approach for spleen TA

    Using the quality circle approach to empower disadvantaged youth in addressing cyberbullying: an exploration across five European countries

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    Digital communication technologies play an important role in the social development of young people, but can create vulnerabilities to cyberbullying and other negative online experiences. The Blurred Lives project aimed to tackle cyberbullying innovatively using a co-participatory approach, collaborating with 14–16-year olds living in areas of socio-economic disadvantage in five European countries. In phase one, 2,658 teenagers were surveyed on their internet use and any unpleasant online experiences. This data informed the second phase where the participating countries worked together with 237 adolescents across 10 schools with adult facilitators to create original anti-cyberbullying resources for teachers, parents/carers, peers, and social media providers using the Quality Circle approach. This methodology adopts an ethos of working together to solve a problem in small, peer-led groups. Each group was tasked with creating a resource for one of the target audience groups. The final resources comprise a rich variety of different formats including videos, comic strips, a board game, leaflets, posters, and newsletters. The pupil feedback highlights, for most but not all participants, an increased knowledge of cyberbullying and e-safety skills, as well as enhanced problem-solving skills, levels of confidence, and group work skills. Several operational challenges are also discussed, including the importance of school-level support, planning, staffing, and finding an appropriate balance between facilitator support and pupil agency

    A review of the MSCA ITN ECOSTORE - Novel complex metal hydrides for efficient and compact storage of renewable energy as hydrogen and electricity

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    Hydrogen as an energy carrier is very versatile in energy storage applications. Developments in novel, sustainable technologies towards a CO2-free society are needed and the exploration of all-solid-state batteries (ASSBs) as well as solid-state hydrogen storage applications based on metal hydrides can provide solutions for such technologies. However, there are still many technical challenges for both hydrogen storage material and ASSBs related to designing low-cost materials with low-environmental impact. The current materials considered for all-solid-state batteries should have high conductivities for Na+, Mg2+ and Ca2+, while Al3+-based compounds are often marginalised due to the lack of suitable electrode and electrolyte materials. In hydrogen storage materials, the sluggish kinetic behaviour of solid-state hydride materials is one of the key constraints that limit their practical uses. Therefore, it is necessary to overcome the kinetic issues of hydride materials before discussing and considering them on the system level. This review summarizes the achievements of the Marie Skłodowska-Curie Actions (MSCA) innovative training network (ITN) ECOSTORE, the aim of which was the investigation of different aspects of (complex) metal hydride materials. Advances in battery and hydrogen storage materials for the efficient and compact storage of renewable energy production are discussed

    Medeuro : the longing for identity and community among Maltese migrant settlers in North Africa

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    Based largely on materials held in the Service des Periodiques at the Bibliotheque Nationale de Tunisie in Tunis, and especially on content anaylsis of a 1930s newspaper Melita published in Sousse. this study explores the yearning for and the anguish of a cultural survivance among Maltese migrant settlers in North Africa, above all the retention of Maltese as a language of expression, affinity and identification, at a time when Maltese itself was experiencing a literary rebirth. However, such a campaign is undertaken in a 'non-Maltese' context, where moreover, in addition to separation and distance, the influence of European empires-the French, the British and the Italian-is pronounced, if not dominant, thus interfering with any continued loyalty to one mother tongue or mother country. Masterminding the intellectual push for a collective self-identity anchored in language, literature, history and religion, is a leading francophone litterateur whose family had settled in Algeria from the island of Gozo. What is also offered here, in the annotations, is a fairly comprehensive bibliography of Maltese migrant settlement in northern Africa with special reference to lesser known articles and other publications not available in English.peer-reviewe
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