581 research outputs found
Scene-based nonuniformity correction with video sequences and registration
We describe a new, to our knowledge, scene-based nonuniformity correction algorithm for array detectors. The algorithm relies on the ability to register a sequence of observed frames in the presence of the fixed-pattern noise caused by pixel-to-pixel nonuniformity. In low-to-moderate levels of nonuniformity, sufficiently accurate registration may be possible with standard scene-based registration techniques. If the registration is accurate, and motion exists between the frames, then groups of independent detectors can be identified that observe the same irradiance (or true scene value). These detector outputs are averaged to generate estimates of the true scene values. With these scene estimates, and the corresponding observed values through a given detector, a curve-fitting procedure is used to estimate the individual detector response parameters. These can then be used to correct for detector nonuniformity. The strength of the algorithm lies in its simplicity and low computational complexity. Experimental results, to illustrate the performance of the algorithm, include the use of visible-range imagery with simulated nonuniformity and infrared imagery with real nonuniformity
The Quantum Socket: Three-Dimensional Wiring for Extensible Quantum Computing
Quantum computing architectures are on the verge of scalability, a key
requirement for the implementation of a universal quantum computer. The next
stage in this quest is the realization of quantum error correction codes, which
will mitigate the impact of faulty quantum information on a quantum computer.
Architectures with ten or more quantum bits (qubits) have been realized using
trapped ions and superconducting circuits. While these implementations are
potentially scalable, true scalability will require systems engineering to
combine quantum and classical hardware. One technology demanding imminent
efforts is the realization of a suitable wiring method for the control and
measurement of a large number of qubits. In this work, we introduce an
interconnect solution for solid-state qubits: The quantum socket. The quantum
socket fully exploits the third dimension to connect classical electronics to
qubits with higher density and better performance than two-dimensional methods
based on wire bonding. The quantum socket is based on spring-mounted micro
wires the three-dimensional wires that push directly on a micro-fabricated
chip, making electrical contact. A small wire cross section (~1 mmm), nearly
non-magnetic components, and functionality at low temperatures make the quantum
socket ideal to operate solid-state qubits. The wires have a coaxial geometry
and operate over a frequency range from DC to 8 GHz, with a contact resistance
of ~150 mohm, an impedance mismatch of ~10 ohm, and minimal crosstalk. As a
proof of principle, we fabricated and used a quantum socket to measure
superconducting resonators at a temperature of ~10 mK.Comment: Main: 31 pages, 19 figs., 8 tables, 8 apps.; suppl.: 4 pages, 5 figs.
(HiRes figs. and movies on request). Submitte
Resettlement experiences and resilience in refugee youth in Perth, Western Australia
Background: In Australia, the two major pathways of refugee entry are the United Nations High Commissioner for Refugees resettlement programme and irregular maritime arrivals (IMAs) seeking asylum. The Australian Government’s policies towards IMAs since July 2013 are controversial, uncompromising and consistently harsh, with asylum seekers held in detention centres for prolonged periods. Refugees and asylum seekers have distinct and unique stressors that make resettlement difficult. Methods: This exploratory study examines resettlement experiences for refugee youth in Western Australia using the psychosocial conceptual framework and qualitative methods. Focus group discussions and key informant interviews were undertaken with verbatim transcripts analysed using thematic analysis to identify themes. Results: Themes documented that language and its impact, and experience with education, health, and social activities, support structures provided to youth and supporting future aspirations as critical to successful resettlement. This exploratory study contributes to developing a broader understanding of the resettlement experiences of refugee youth, drawing on their current and past experiences, cultural differences and mechanisms for coping. Conclusion: Fluency in English language, especially spoken, was a facilitator of successful resettlement. Our results align with previous studies documenting that support programs are vital for successful resettlement. Although faced with immense difficulties refugee youth are resilient, want to succeed and have aspirations for the future. Strategies and recommendations suggested by refugee youth themselves could be used for developing interventions to assist successful resettlement
Predictors of Nonsentinel Nodal Involvement to Aid Intraoperative Decision Making in Breast Cancer Patients with Positive Sentinel Lymph Nodes
Background. Up to 60% of patients with a positive sentinel lymph node (SLN) have no additional nodal involvement and do not benefit from completion axillary lymph node dissection (ALND). We aim to identify factors predicting for non-SLN involvement and to validate the MSKCC nomogram and Tenon score in our population. Methods. Retrospective review was performed of 110 consecutive patients with positive SLNs who underwent ALND over an 8-year period. Results. Fifty patients (45%) had non-SLN involvement. Non-SLN involvement correlated positively with the number of positive SLNs (P = 0.04), macrometastasis (P = 0.01), and inversely with the total number of SLNs harvested (P = 0.03). The MSKCC nomogram and Tenon score both failed to perform as previously reported. Conclusions. The MSKCC nomogram and Tenon score have limited value in our practice. Instead, we identified three independent predictors, which are more relevant in guiding the intraoperative decision for ALND
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