147 research outputs found

    Tuning the emission wavelength of Si nanocrystals in SiO2 by oxidation

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    Si nanocrystals (diameter 2–5 nm) were formed by 35 keV Si + implantation at a fluence of 6 × 1016 Si/cm2 into a 100 nm thick thermally grown SiO2 film on Si (100), followed by thermal annealing at 1100 °C for 10 min. The nanocrystals show a broad photoluminescence spectrum, peaking at 880 nm, attributed to the recombination of quantum confined excitons. Rutherford backscattering spectrometry and transmission electron microscopy show that annealing these samples in flowing O2 at 1000 °C for times up to 30 min results in oxidation of the Si nanocrystals, first close to the SiO2 film surface and later at greater depths. Upon oxidation for 30 min the photoluminescence peak wavelength blueshifts by more than 200 nm. This blueshift is attributed to a quantum size effect in which a reduction of the average nanocrystal size leads to emission at shorter wavelengths. The room temperature luminescence lifetime measured at 700 nm increases from 12 µs for the unoxidized film to 43 µs for the film that was oxidized for 29 min

    In situ real-time analysis of alloy film composition and segregation dynamics with parallel detection reflection electron energy loss spectroscopy

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    Real-time measurements of GexSi1 – x/Si(001) composition and segregation dynamics in Sn/Si(001) in molecular beam epitaxy are demonstrated using parallel detection reflection electron energy loss spectroscopy. Parallel detection enables quantitative acquisition of low-loss spectra in a time of < 500 µs and surface composition determination in GexSi1 – x/Si(001) via Ge L2,3 core loss analysis to a precision of approximately 2% in time of order 1 s. Segregation and trapping kinetics of monolayer thickness Sn films during Si epitaxy on Sn-covered Si(100) has also been studied using the Sn M4.5 core loss

    Air-gap gating of MgZnO/ZnO heterostructures

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    The adaptation of “air-gap” dielectric based field-effect transistor technology to controlling the MgZnO/ZnO heterointerface confined two-dimensional electron system (2DES) is reported. We find it possible to tune the charge density of the 2DES via a gate electrode spatially separated from the heterostructure surface by a distance of 5 μm. Under static gating, the observation of the quantum Hall effect suggests that the charge carrier density remains homogeneous, with the 2DES in the 3 mm square sample the sole conductor. The availability of this technology enables the exploration of the charge carrier density degree of freedom in the pristine sample limit

    Air-gap gating of MgZnO/ZnO heterostructures

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    The adaptation of “air-gap” dielectric based field-effect transistor technology to controlling the MgZnO/ZnO heterointerface confined two-dimensional electron system (2DES) is reported. We find it possible to tune the charge density of the 2DES via a gate electrode spatially separated from the heterostructure surface by a distance of 5 μm. Under static gating, the observation of the quantum Hall effect suggests that the charge carrier density remains homogeneous, with the 2DES in the 3 mm square sample the sole conductor. The availability of this technology enables the exploration of the charge carrier density degree of freedom in the pristine sample limit

    A scoping review of market links between value chain actors and small-scale producers in developing regions

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    Sustainable Development Goal 2 aims to end hunger, achieve food and nutrition security and promote sustainable agriculture by 2030. This requires that small-scale producers be included in, and benefit from, the rapid growth and transformation under way in food systems. Small-scale producers interact with various actors when they link with markets, including product traders, logistics firms, processors and retailers. The literature has explored primarily how large firms interact with farmers through formal contracts and resource provision arrangements. Although important, contracts constitute a very small share of smallholder market interactions. There has been little exploration of whether non-contract interactions between small farmers and both small- and large-scale value chain actors have affected small farmers’ livelihoods. This scoping review covers 202 studies on that topic. We find that non-contract interactions, de facto mostly with small and medium enterprises, benefit small-scale producers via similar mechanisms that the literature has previously credited to large firms. Small and medium enterprises, not just large enterprises, address idiosyncratic market failures and asset shortfalls of small-scale producers by providing them, through informal arrangements, with complementary services such as input provision, credit, information and logistics. Providing these services directly supports Sustainable Development Goal 2 by improving farmer welfare through technology adoption and greater productivity

    Psychosocial effects of an Ebola outbreak at individual, community and international levels.

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    The 2013-2016 Ebola outbreak in Guinea, Liberia and Sierra Leone was the worst in history with over 28,000 cases and 11,000 deaths. Here we examine the psychosocial consequences of the epidemic. Ebola is a traumatic illness both in terms of symptom severity and mortality rates. Those affected are likely to experience psychological effects due to the traumatic course of the infection, fear of death and experience of witnessing others dying. Survivors can also experience psychosocial consequences due to feelings of shame or guilt (e.g. from transmitting infection to others) and stigmatization or blame from their communities. At the community level, a cyclical pattern of fear occurs, with a loss of trust in health services and stigma, resulting in disruptions of community interactions and community break down. Health systems in affected countries were severely disrupted and overstretched by the outbreak and their capacities were significantly reduced as almost 900 health-care workers were infected with Ebola and more than 500 died. The outbreak resulted in an increased need for health services, reduced quality of life and economic productivity and social system break down. It is essential that the global response to the outbreak considers both acute and long-term psychosocial needs of individuals and communities. Response efforts should involve communities to address psychosocial need, to rebuild health systems and trust and to limit stigma. The severity of this epidemic and its long-lasting repercussions should spur investment in and development of health systems

    Nursing students’ experience of learning cultural competence

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    Introduction European societies are rapidly becoming multicultural. Cultural diversity presents new challenges and opportunities to communities that receive immigrants and migrants, and highlights the need for culturally safe healthcare. Universities share a responsibility to build a fair and equitable society by integrating cultural content in the nursing curricula. This paper aims to analyze European student nurses´ experience of learning cultural competence and of working with patients from diverse cultural backgrounds. Materials and methods A phenomenological approach was selected through a qualitative research method. 7 semi-structured focus groups with 5–7 students took place at the participants’ respective universities in Spain, Belgium, Turkey and Portugal. Results 5 themes and 16 subthemes emerged from thematic analysis. Theme 1, concept of culture/ cultural diversity, describes the participants’ concept of culture; ethnocentricity emerged as a frequent element in the students’ discourse. Theme 2, personal awareness, integrates the students’ self-perception of cultural competence and their learning needs. Theme 3, impact of culture, delves on the participants’ perceived impact of cultural on both nursing care and patient outcomes. Theme 4, learning cultural competence, integrates the participants’ learning experiences as part of their nursing curricula, as part of other academic learning opportunities and as part of extra-academic activities. Theme 5, learning cultural competence during practice placements, addresses some important issues including witnessing unequal care, racism, prejudice and conflict, communication and language barriers, tools and resources and positive attitudes and behaviors witnesses or displayed during clinical practice. Conclusion The participants’ perceived level of cultural competence was variable. All the participants agreed that transcultural nursing content should be integrated in the nursing curricula, and suggested different strategies to improve their knowledge, skills and attitudes. It is important to listen to the students and take their opinion into account when designing cultural teaching and learning activities. © 2021 Antón-Solanas et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

    Nursing lecturers’ perception and experience of teaching cultural competence: a european qualitative study

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    Cultural competence is an essential component in providing effective and culturally responsive healthcare services, reducing health inequalities, challenging racism in health care and improving patient safety, satisfaction and health outcomes. It is thus reasonable that undergraduate nursing students can develop cultural competency through education and training. The aim of this paper was to investigate nursing lecturers’ perception and experience of teaching cultural competence in four undergraduate nursing programs. A phenomenological approach was selected to illicit nursing lecturers’ perception of culture and experience of teaching cultural competence. Semi-struc-tured personal interviews were held with a sample of 24 lecturers from four European universities. The anonymized transcripts were analyzed qualitatively following Braun and Clark’s phases for thematic analysis. Six themes and fifteen subthemes emerged from thematic analysis of the tran-scripts. Cultural competence was not explicitly integrated in the nursing curricula. Instead, the lecturers used mainly examples and case studies to illustrate the theory. The integration of cultural content in the modules was unplanned and not based on a specific model. Nursing programs should be examined to establish how cultural content is integrated in the curricula; clear guidelines and standards for a systematic integration of cultural content in the nursing curriculum should be de-veloped

    Feasibility and Coverage of Implementing Intermittent Preventive Treatment of Malaria in Pregnant women Contacting Private or Public Clinics in Tanzania: Experience-based Viewpoints of Health Managers in Mkuranga and Mufindi districts.

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    Evidence on healthcare managers' experience on operational feasibility of malaria intermittent preventive treatment for malaria during pregnancy (IPTp) using sulphadoxine-pyrimethamine (SP) in Africa is systematically inadequate. This paper elucidates the perspectives of District Council Health Management Team (CHMT)s regarding the feasibility of IPTp with SP strategy, including its acceptability and ability of district health care systems to cope with the contemporary and potential challenges. The study was conducted in Mkuranga and Mufindi districts. Data were collected between November 2005 and December 2007, involving focus group discussion (FGD) with Mufindi CHMT and in-depth interviews were conducted with few CHMT members in Mkuranga where it was difficult to summon all members for FGD. Participants in both districts acknowledged the IPTp strategy, considering the seriousness of malaria in pregnancy problem; government allocation of funds to support healthcare staff training programmes in focused antenatal care (fANC) issues, procuring essential drugs distributed to districts, staff remuneration, distribution of fANC guidelines, and administrative activities performed by CHMTs. The identified weaknesses include late arrival of funds from central level weakening CHMT's performance in health supervision, organising outreach clinics, distributing essential supplies, and delivery of IPTp services. Participants anticipated the public losing confidence in SP for IPTp after government announced artemither-lumefantrine (ALu) as the new first-line drug for uncomplicated malaria replacing SP. Role of private healthcare staff in IPTp services was acknowledged cautiously because CHMTs rarely supplied private clinics with SP for free delivery in fear that clients would be required to pay for the SP contrary to government policy. In Mufindi, the District Council showed a strong political support by supplementing ANC clinics with bottled water; in Mkuranga such support was not experienced. A combination of health facility understaffing, water scarcity and staff non-adherence to directly observed therapy instructions forced healthcare staff to allow clients to take SP at home. Need for investigating in improving adherence to IPTp administration was emphasised. High acceptability of the IPTp strategy at district level is meaningless unless necessary support is assured in terms of number, skills and motivation of caregivers and availability of essential supplies
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