1,068 research outputs found

    Optimization of MLS receivers for multipath environments

    Get PDF
    Optimal design studies of MLS angle-receivers and a theoretical design-study of MLS DME-receivers are reported. The angle-receiver results include an integration of the scan data processor and tracking filter components of the optimal receiver into a unified structure. An extensive simulation study comparing the performance of the optimal and threshold receivers in a wide variety of representative dynamical interference environments was made. The optimal receiver was generally superior. A simulation of the performance of the threshold and delay-and-compare receivers in various signal environments was performed. An analysis of combined errors due to lateral reflections from vertical structures with small differential path delays, specular ground reflections with neglible differential path delays, and thermal noise in the receivers is provided

    Optimization of MLS receivers for multipath environments

    Get PDF
    A receiver is designed for aircraft (A/C), which, as a component of the proposed Microwave Landing System (MLS), is capable of optimal performance in the multipath environments found in air terminal areas. Topics discussed include: the angle-tracking problem of the MLS receiver; signal modeling; preliminary approaches to optimal design; suboptimal design; and simulation study

    Violence, uncertainty, and resilience among refugee women and community workers: An evaluation of gender-based violence case management services in the Dadaab refugee camps.

    Get PDF
    Reports of gender-based violence (GBV) are common in camps for refugees and displaced populations. In the Dadaab refugee camps in north-eastern Kenya, the International Rescue Committee (IRC) and CARE International (CARE) implement programmes that aim to both respond to and prevent GBV. A cornerstone of this work has been to train refugees, known as refugee community workers, to deliver aspects of GBV prevention and response work in order to develop a broader implementation of traditional GBV outreach, community mobilisation, and case management. To date, there has been limited rigorous research on this broader GBV case management plus task sharing approach in the context of a refugee camp setting. To address this key gap in evidence, the London School of Hygiene and Tropical Medicine (LSHTM) and the African Population and Health Research Centre (APHRC), in collaboration with IRC and CARE, have sought to assess this model to understand its feasibility, acceptability, and influence among female survivors of GBV accessing care. Data for this study, funded by UK aid, were collected in the Dadaab refugee camps between 2014 and 2017, which coincided with a temporary decision to close the camp and repatriate Somali refugees. The research confirms the magnitude and complexity of the violence that women and girls experience in the camps in Dadaab. In the year leading up to this study, 47% of women accessing the GBV centres for case management reported experiencing intimate partner violence and 39% reported experiencing non-partner violence. In addition, the study highlights the specific risks, challenges, opportunities and rewards experienced by refugee community workers in their dual role of community members and GBV activists living side-by-side with survivors and perpetrators of violence. Solely related to their work as GBV caseworkers, one in three refugee community workers reported experiencing non-partner violence in the last 12 months. Despite this, 93% of refugee community workers stated their work was rewarding or extremely rewarding. The majority of women (82%) accessing services reported that their interactions with refugee community workers had a positive effect, and that working with them was useful. However, having refugees deliver services to their own community was not without its challenges, and survivors raised issues on confidentiality, mistranslations, and perceived biases on clan differences. The study also provides an insight into the importance of contextual factors in case management, and the impact of the announcement of the (now-delayed) camp closure in Dadaab. Priorities of both the camp population and service providers (GBV and referral services) shifted greatly during this time of uncertainty and affected when and how women were accessing services

    Gender-based violence and its association with mental health among Somali women in a Kenyan refugee camp: a latent class analysis

    Get PDF
    BACKGROUND: In conflict-affected settings, women and girls are vulnerable to gender-based violence (GBV). GBV is associated with poor long-term mental health such as anxiety, depression and post-traumatic stress disorder (PTSD). Understanding the interaction between current violence and past conflict-related violence with ongoing mental health is essential for improving mental health service provision in refugee camps. METHODS: Using data collected from 209 women attending GBV case management centres in the Dadaab refugee camps, Kenya, we grouped women by recent experience of GBV using latent class analysis and modelled the relationship between the groups and symptomatic scores for anxiety, depression and PTSD using linear regression. RESULTS: Women with past-year experience of intimate partner violence alone may have a higher risk of depression than women with past-year experience of non-partner violence alone (Coef. 1.68, 95% CI 0.25 to 3.11). Conflict-related violence was an important risk factor for poor mental health among women who accessed GBV services, despite time since occurrence (average time in camp was 11.5 years) and even for those with a past-year experience of GBV (Anxiety: 3.48, 1.85-5.10; Depression: 2.26, 0.51-4.02; PTSD: 6.83, 4.21-9.44). CONCLUSION: Refugee women who experienced past-year intimate partner violence or conflict-related violence may be at increased risk of depression, anxiety or PTSD. Service providers should be aware that compared to the general refugee population, women who have experienced violence may require additional psychological support and recognise the enduring impact of violence that occurred before, during and after periods of conflict and tailor outreach and treatment services accordingly

    Single Spin Measurement using Single Electron Transistors to Probe Two Electron Systems

    Get PDF
    We present a method for measuring single spins embedded in a solid by probing two electron systems with a single electron transistor (SET). Restrictions imposed by the Pauli Principle on allowed two electron states mean that the spin state of such systems has a profound impact on the orbital states (positions) of the electrons, a parameter which SET's are extremely well suited to measure. We focus on a particular system capable of being fabricated with current technology: a Te double donor in Si adjacent to a Si/SiO2 interface and lying directly beneath the SET island electrode, and we outline a measurement strategy capable of resolving single electron and nuclear spins in this system. We discuss the limitations of the measurement imposed by spin scattering arising from fluctuations emanating from the SET and from lattice phonons. We conclude that measurement of single spins, a necessary requirement for several proposed quantum computer architectures, is feasible in Si using this strategy.Comment: 22 Pages, 8 Figures; revised version contains updated references and small textual changes. Submitted to Phys. Rev.

    Towards the fabrication of phosphorus qubits for a silicon quantum computer

    Full text link
    The quest to build a quantum computer has been inspired by the recognition of the formidable computational power such a device could offer. In particular silicon-based proposals, using the nuclear or electron spin of dopants as qubits, are attractive due to the long spin relaxation times involved, their scalability, and the ease of integration with existing silicon technology. Fabrication of such devices however requires atomic scale manipulation - an immense technological challenge. We demonstrate that it is possible to fabricate an atomically-precise linear array of single phosphorus bearing molecules on a silicon surface with the required dimensions for the fabrication of a silicon-based quantum computer. We also discuss strategies for the encapsulation of these phosphorus atoms by subsequent silicon crystal growth.Comment: To Appear in Phys. Rev. B Rapid Comm. 5 pages, 5 color figure

    Joule-assisted silicidation for short-channel silicon nanowire devices

    Full text link
    We report on a technique enabling electrical control of the contact silicidation process in silicon nanowire devices. Undoped silicon nanowires were contacted by pairs of nickel electrodes and each contact was selectively silicided by means of the Joule effect. By a realtime monitoring of the nanowire electrical resistance during the contact silicidation process we were able to fabricate nickel-silicide/silicon/nickel- silicide devices with controlled silicon channel length down to 8 nm.Comment: 6 pages, 4 figure
    • 

    corecore