33 research outputs found

    Building Teacher Capacity to Support English Language Learners in Schools Receiving School Improvement Grants

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    The Study of School Turnaround examines the improvement process in a purposive sample of 35 case study schools receiving federal funds through the School Improvement Grants (SIG) program over a three-year period (2010 -- 11 to 2012 -- 13 school years). This brief focuses on 11 of these SIG schools with high proportions of English Language Learner (ELL) students (a median of 45 percent ELLs), describing their efforts to improve teachers' capacity for serving ELLs through staffing strategies and professional development (PD). Key findings that emerged from the ELL case study data collected during the 2011 -- 12 and 2012 -- 13 school years include:Few schools reported leveraging staffing strategies to improve teacher capacity for serving ELLs. Administrators in 3 of the 11 schools reported considering ELL expertise and experience when hiring classroom teachers, while respondents in 2 of the 11 schools reported that teachers' ELL expertise and experience purposefully factored into assignment of teachers to specific classrooms.Most teacher survey respondents (54 to 100 percent) in all 11 schools reported participating in ELL-related PD during the 2011 -- 12 school year. On average, teachers reported that ELL-related PD accounted for less than 20 percent of their total PD hours.Teacher survey respondents in schools that reported a greater PD focus on ELL-related topics, such as instructional strategies for advancing English proficiency or instructional strategies to use for ELLs within content classes, also generally appeared more likely to report that PD improved their effectiveness as teachers of ELLs

    Recycling of beta-Li3PS4-based all-solid-state Li-ion batteries: Interactions of electrode materials and electrolyte in a dissolution-based separation process

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    All-solid-state batteries are currently developed at high pace and show a strong potential for market introduction within the next years. Though their performance has improved considerably over the last years, investigation of their sustainability and the development of suitable recycling strategies have received less attention. However, their potential for efficient circular processes must be accessed comprehensively. In this article, we investigate the separation of the solid electrolyte beta-Li3PS4 from different lithium transition metal oxide electrode materials (LiCoO2, LiMn2O4, LiNi0.8Mn0.1Co0.1O2, LiFePO4, LiNi0.85Co0.1Al0.05O2 and Li4Ti5O12) via an approach based on the dissolution and subsequent recrystallization of the thiophosphate using N-methylformamide as solvent. A combination of X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, inductively coupled plasma-mass spectrometry, iodometric titration and X-ray photoelectron spectroscopy as well as electrochemical impedance spectroscopy and electrochemical characterization was used to characterize the electrolyte and electrode materials before and after separation. We find that the presence of electrode materials in the dissolution process can lead to significant chemical reactions. These interactions can (but most not) lead to strong alteration of the electrochemical characteristics of the individual compounds. Thus, we show that an efficient recovery of materials will likely depend on the precise material combination within an all-solid-state battery

    Synthesis, structure and electrical conductivity of a new perovskite type barium cobaltate BaCoO1.80(OH)0.86

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    Perovskite oxides exhibiting mixed protonic and electronic conductivities have interesting applications in protonic ceramic fuel cells. In this work, we report on a hydrated phase of BaCoO1.80(OH)0.86 synthesized using nebulized spray pyrolysis. Structural analysis based on X-ray and neutron powder diffraction data showed that the compound is isotypic to BaFeO2.33(OH)0.33. The water loss behaviour was studied using simultaneous thermal analysis and high temperature X-ray diffraction, indicating that protons (respectively water) can be stabilized within the compound up to temperatures significantly above 673 K, confirmed by ex situ Fourier transform infrared spectroscopy studies. Impedance spectroscopy was used to determine the conductivity characteristics of BaCoO1.80(OH)0.86, finding and a total electrical conductivity in the order of 10−4 S cm−1 at ambient temperature with an activation energy of 0.28 eV

    The Impact of Pneumococcal Conjugate Vaccine (PCV) Coverage Heterogeneities on the Changing Epidemiology of Invasive Pneumococcal Disease in Switzerland, 2005–2019

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    Pneumococcal conjugate vaccines (PCVs) have lowered the incidence of invasive pneumococcal disease (IPD) worldwide. However, the influence of regional vaccine uptake differences on the changing epidemiology of IPD remains unclear. We aimed to examine the overall impact of both seven- and 13-valent PCVs (PCV7 and PCV13) on IPD in Switzerland. Three-year periods from 2005–2010 and 2011–2019 were considered, respectively, as (early and late) PCV7 eras and (early, mid and late) PCV13 eras. Vaccine coverage was estimated from a nationwide survey according to east (German-speaking) and west (French/Italian-speaking) regions for each period. Reported incidence rate ratios (IRRs) were compared between successive periods and regions using nationwide IPD surveillance data. Overall IPD incidence across all ages was only 16% lower in the late PCV13 era compared to the early PCV7 era (IRR 0.83, 95% CI 0.79–0.88), due to increasing incidence of non-PCV-type IPD (2.59, 2.37–2.83) in all age groups, except children <5 years. PCV uptake rates in swiss children were slightly higher in the west than the east (p < 0.001), and were accompanied by lower IPD incidences across all age groups in the former region. Post-PCV13, non-PCV serotypes 8, 22F and 9N were the major cause of IPD in adults ≥65 years. Increased PCV coverage in both areas of Switzerland resulted in a decrease in vaccine-type and overall IPD incidence across all age groups, in a regionally dependent manner. However, the rising incidence of non-vaccine-type IPD, exclusive to older adults, may undermine indirect beneficial effects

    Electrochemical Reduction and Oxidation of Ruddlesden–Popper-Type La2_{2}NiO3_{3}F2_{2} within Fluoride-Ion Batteries

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    Within this article, it is shown that an electrochemical defluorination and additional fluorination of Ruddlesden–Popper-type La2_2NiO3_3F2_2 is possible within all-solid-state fluoride-ion batteries. Structural changes within the reduced and oxidized phases have been examined by X-ray diffraction studies at different states of charging and discharging. The synthesis of the oxidized phase La2_2NiO3_3F2+x_{2+x} proved to be successful by structural analysis using both X-ray powder diffraction and automated electron diffraction tomography techniques. The structural reversibility on re-fluorinating and re-defluorinating is also demonstrated. Moreover, the influence of different sequences of consecutive reduction and oxidation steps on the formed phases has been investigated. The observed structural changes have been compared to changes in phases obtained via other topochemical modification approaches such as hydride-based reduction and oxidative fluorination using F2_2 gas, highlighting the potential of such electrochemical reactions as alternative synthesis routes. Furthermore, the electrochemical routes represent safe and controllable synthesis approaches for novel phases, which cannot be synthesized via other topochemical methods. Additionally, side reactions, occurring alongside the desired electrochemical reactions, have been addressed and the cycling performance has been studied

    Topochemical Fluorination of La2NiO4+d::Unprecedented ordering of oxide and fluoride ions in La2NiO3F2

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    Synopsis La2NiO3F2 crystallizes in a new anion-ordered distortion variant of the n = 1 Ruddlesden−Popper-type structure. The unprecedented ordering of oxygen anions in the interlayer leads to an expansion of the lattice perpendicular to the stacking direction, accompanied by a strong tilting of NiO4F2 octahedra. A weakening of Ni−F−F−Ni superexchange interactions between the perovskite-type layers due to the reduced covalency of fluoride ions decreases the magnetic ordering temperature strongly. Abstract The Ruddlesden–Popper (K2NiF4) type phase La2NiO3F2 was prepared via a polymer-based fluorination of La2NiO4+d. The compound was found to crystallize in the orthorhombic space group Cccm (a = 12.8350(4) Å, b = 5.7935(2) Å, c = 5.4864(2) Å). This structural distortion results from an ordered half occupation of the interstitial anion layers and has not been observed previously for K2NiF4-type oxyfluoride compounds. From a combination of neutron and X-ray powder diffraction and 19F magic-angle spinning NMR spectroscopy, it was found that the fluoride ions are only located on the apical anion sites, whereas the oxide ions are located on the interstitial sites. This ordering results in a weakening of the magnetic Ni–F–F–Ni superexchange interactions between the perovskite layers and a reduction of the antiferromagnetic ordering temperature to 49 K. Below 30 K, a small ferromagnetic component was found, which may be the result of a magnetic canting within the antiferromagnetic arrangement and will be the subject of a future low-temperature neutron diffraction study. Additionally, density functional theory-based calculations were performed to further investigate different anion ordering scenarios

    Novel Echinacea formulations for the treatment of acute respiratory tract infections in adults—A randomized blinded controlled trial

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    BackgroundEchinacea purpurea has clinical antiviral activity against respiratory viruses and modulates immune functions. In this study, we compared higher doses of new Echinacea formulations with conventional formulations at lower, preventive doses for therapy of respiratory tract infections (RTIs).MethodsIn this randomized, blinded, controlled trial, healthy adults (n = 409) were randomized between November 2018 and January 2019 to one of four Echinacea formulations, which were taken in case of an RTI for up to 10 days. New formulations A (lozenges) and B (spray) delivered an increased dose of 16,800 mg/d Echinacea extract during days 1–3 and 2,240–3,360 mg/d afterward; as controls, conventional formulations C (tablets) and D (drops) delivered a lower daily dose of 2,400 mg, usually taken for prevention. The primary endpoint was time to clinical remission of first RTI episodes based on the Kaplan–Meier analysis of patient-reported, investigator-confirmed, respiratory symptoms assessed for up to 10 days. In a sensitivity analysis, the mean time to remission beyond day 10 was calculated by extrapolating the treatment effects observed on days 7 to 10.ResultsA total of 246 participants (median age 32 years, 78% female participants) were treated for at least one RTI. Recovery by day 10 (complete absence of symptoms) was achieved in 56 and 44% of patients with the new and conventional formulations, respectively, showing a median time to recovery of 10 and 11 days, respectively (p = 0.10 in intention-to-treat analysis, p = 0.07 in per-protocol analysis). In the extrapolated sensitivity analysis, new formulations resulted in a significantly shorter mean time to remission (9.6 vs. 11.0 days, p &lt; 0.001). Among those with an identified respiratory virus, viral clearance until day 10 based on real-time PCR from nasopharyngeal swabs was more frequent with new formulations (70 vs. 53%, p = 0.046). Tolerability and safety (adverse events: 12 vs. 6%, p = 0.19) were good and similar between formulations. There was one severe adverse event with a potential hypersensitivity reaction in a recipient of the novel spray formulation.ConclusionIn adults with acute RTI, new Echinacea formulations with higher doses resulted in faster viral clearance than conventional formulations in prophylactic dosages. The trend for faster clinical recovery was not significant by day 10 but became so upon extrapolation. A dose increase during acute respiratory symptoms might improve the clinical benefits of orally administered Echinacea formulations.Trial registrationThe study was registered in the Swiss National Clinical Trials Portal (SNCTP000003069) and on ClinicalTrials.gov (NTC03812900; URL https://clinicaltrials.gov/ct2/show/NCT03812900?cond=echinacea&amp;draw=3&amp;rank=14)

    Topochemical fluorination and defluorination in the context of fluoride-ion batteries and tuning of magnetic properties

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    Within this work, it was demonstrated that topochemical modifications of the anion sublattices of Ruddlesden-Popper-type oxides An+1BnO3n+1 and derived metastable oxyfluorides An+1BnO3n+1-xF2x with 0 < x ≤ 2 have a significant influence on the crystal and electronic structures of the newly synthesised phases. This could be used to effectively tailor and reversibly tune magnetic properties. Different non-oxidative, reductive or oxidative modification routes, leading to fluoride intercalation, exchange and/or deintercalation processes, were investigated. Such topochemical reactions have been also found to take place upon the electrochemical fluorination of Ruddlesden-Popper-type oxides in fluoride-ion batteries and have led to the development of intercalation-based cathode materials. For the development of novel intercalation-based electrodes, oxyfluorides, obtained via a prior non-oxidative topochemical fluorination of the respective oxides, were examined concerning their potential use as active anode or cathode materials. During charging, the use of the oxyfluoride as active anode material results in defluorination, whereas additional fluorination occurs when the oxyfluoride contains additional vacancies and is used as active cathode material. For both cases, the oxyfluoride represents the discharged state of the electrode material. These additional topochemical modifications of the parent oxyfluorides could be also achieved via chemical preparation approaches. For the chemical preparation of the anode material in the charged state, a reductive defluorination method based on sodium hydride was developed. The additional fluorination was performed using highly oxidising F2 gas. The non-oxidatively fluorinated oxyfluorides Sr2TiO3F2, Sr3Ti2O5F4 and La2NiO3F2 were modified accordingly. A focus was set on the defluorination of these phases, since this is related to the development of intercalation-based anode materials, a field, which has been conceptionally unexplored prior to this work. However, the structural stability of the oxyfluorides within the electrode composites was found only for Sr3Ti2O5F2 and La2NiO3F2, of which primarily La2NiO3F2 showed redox activity. This Ni-based phase could be successfully electrochemically defluorinated as well as additionally fluorinated, showing its potential to serve as both, active anode and cathode material. The resulting composition-induced alterations of the crystal structure and magnetic properties of the chemically and electrochemically obtained phases were analysed by a variety of characterisation techniques, including different diffraction and spectroscopy methods, DFT-based calculations and magnetic measurements. The chemically and electrochemically formed phases showed to be structurally related. Therefore, the structural and magnetic characteristics of the chemically prepared phases, which were analysed in-depth, could be transferred to the electrochemically synthesised phases. Magnetic properties, related to the presence or absence of unpaired electrons and the strength of exchange interactions, were found to be highly dependent on the structural modifications and transition metal cation oxidations states. Even though a generally detrimental effect of irreversible side reactions, resulting in the progressive decrease of the electronic conductivity of the carbon additive, was found to exist, the reversibility of the structural changes over extended cycling was observed. This was found to offer the possibility to switch reversibly between different magnetic states of the charged and discharged phases. A detailed investigation of magnetoelectric switching due to reversible fluoride intercalation was performed on La1.3Sr1.7Mn2O7. A switching between a strongly and weakly ferromagnetic state could be achieved, resulting in high relative changes of the magnetisation with one of the highest reported magnetoelectric voltage couplings reported for tuneable magnetic systems

    Recycling of solid-state batteries—challenge and opportunity for a circular economy?

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    The tremendous efforts made in the research field of solid-state Li-ion batteries have led to considerable advancement of this technology and the first market-ready systems can be expected in the near future. The research community is currently investigating different solid-state electrolyte classes (e.g. oxides, sulfides, halides and polymers) with a focus on further optimizing the synthesis and electrochemical performance. However, so far, the development of sustainable recycling strategies allowing for an efficient backflow of critical elements contained in these batteries into the economic cycle and thus a transition from a linear to a circular economy lags behind. In this contribution, resource aspects with respect to the chemical value of crucial materials, which are used for the synthesis of solid-state electrolytes are being discussed. Furthermore, an overview of possible approaches in relation to their challenges and opportunities for the recycling of solid-state batteries with respect to different solid-state electrolyte classes by means of pyrometallurgy, hydrometallurgy and direct recycling/dissolution-based separation processes is given. Based on these considerations and with reference to previous research, it will be shown that different solid-state electrolytes will require individually adapted recycling processes to be suitably designed for a circular economy and that further improvements and investigations will be required

    The Impact of Pneumococcal Conjugate Vaccine (PCV) Coverage Heterogeneities on the Changing Epidemiology of Invasive Pneumococcal Disease in Switzerland, 2005-2019

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    Pneumococcal conjugate vaccines (PCVs) have lowered the incidence of invasive pneumococcal disease (IPD) worldwide. However, the influence of regional vaccine uptake differences on the changing epidemiology of IPD remains unclear. We aimed to examine the overall impact of both seven- and 13-valent PCVs (PCV7 and PCV13) on IPD in Switzerland. Three-year periods from 2005-2010 and 2011-2019 were considered, respectively, as (early and late) PCV7 eras and (early, mid and late) PCV13 eras. Vaccine coverage was estimated from a nationwide survey according to east (German-speaking) and west (French/Italian-speaking) regions for each period. Reported incidence rate ratios (IRRs) were compared between successive periods and regions using nationwide IPD surveillance data. Overall IPD incidence across all ages was only 16% lower in the late PCV13 era compared to the early PCV7 era (IRR 0.83, 95% CI 0.79-0.88), due to increasing incidence of non-PCV-type IPD (2.59, 2.37-2.83) in all age groups, except children <5 years. PCV uptake rates in swiss children were slightly higher in the west than the east (p < 0.001), and were accompanied by lower IPD incidences across all age groups in the former region. Post-PCV13, non-PCV serotypes 8, 22F and 9N were the major cause of IPD in adults ≥65 years. Increased PCV coverage in both areas of Switzerland resulted in a decrease in vaccine-type and overall IPD incidence across all age groups, in a regionally dependent manner. However, the rising incidence of non-vaccine-type IPD, exclusive to older adults, may undermine indirect beneficial effects
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