Resolved-sideband laser cooling in a penning trap

We report the laser cooling of a single $^{40}\text{Ca}^+$ ion in a Penning trap to the motional ground state in one dimension. Cooling is performed in the strong binding limit on the 729-nm electric quadrupole $S_{1/2}\leftrightarrow D_{5/2}$ transition, broadened by a quench laser coupling the $D_{5/2}$ and $P_{3/2}$ levels. We find the final ground state occupation to be $98\pm1\%$. We measure the heating rate of the trap to be very low with $\dot{\bar{n}}\approx 0.3\pm0.2\textrm{s}^{-1}$ for trap frequencies from $150-400\textrm{kHz}$, consistent with the large ion-electrode distance.Comment: 4 pages, 6 figures. Accepted: Phys. Rev. Lett. (2016) http://journals.aps.org/prl/accepted/b6074YefH1115b5881f77975417a6ae0bc9f652a

Non-operative Treatment of Advanced Limb Ischaemia: the Decision for Palliative Care

AbstractObjectives: to identify and describe patients with advanced limb ischaemia who were selected for palliative care, rather than surgical intervention. Design: case-note review of patients identified from a prospective register. Materials and methods: thirty patients (22 female; median age 87 years) were identified during 1993–1998, for whom a clearly documented decision was made for palliative care, rather than major amputation or possible revascularisation.Results: two-thirds of the patients had limiting cardiac problems, two-thirds were immobile, and 47% had suffered a stroke. Half had three or more important co-morbidities. Twelve (40%) had unsalvageable acute ischaemia. There were clear records of the decision about non-intervention being made by a consultant in 87%; being discussed with the patient in 43%; and with known relatives in 90%. Survival after this decision ranged from <24 hours to 42 days (median 3.5 days). Conclusion: there is a small subgroup of patients with advanced ischaemia who are best treated palliatively, and who have not been well described before. Recognising these patients, recording discussions about their management, and a high standard of terminal care are all important

The impact of socio-economic status on melanoma clinical trial participation: an observational cohort study from Australia.

Low socio-economic status (SES) is reported to be a barrier to participation in cancer clinical trials due to out-of-pocket costs associated with trial participation, logistical barriers to attend screening services in different diagnostic and treatment centers, and associated cultural or linguistic barriers. One study of clinical trial participation in the ocular melanoma population, reported somewhat different results, whereby people of an older age (≥60 years), lower education level, and those with non-managerial jobs were more likely to participate in a clinical trial, than their younger, more educated counterparts. The aim of the present study was to determine whether SES was associated with participation in clinical trials for people with cutaneous melanoma

The impact of socio-economic status on melanoma clinical trial participation: an observational cohort study from Australia.

Low socio-economic status (SES) is reported to be a barrier to participation in cancer clinical trials due to out-of-pocket costs associated with trial participation, logistical barriers to attend screening services in different diagnostic and treatment centers, and associated cultural or linguistic barriers. One study of clinical trial participation in the ocular melanoma population, reported somewhat different results, whereby people of an older age (≥60 years), lower education level, and those with non-managerial jobs were more likely to participate in a clinical trial, than their younger, more educated counterparts. The aim of the present study was to determine whether SES was associated with participation in clinical trials for people with cutaneous melanoma

Patients' perspectives of long-term follow-up for localised cutaneous melanoma

Background Little is known about the value of long-term follow-up for localised cutaneous melanoma from the patients' perspective. This study aimed to explore the benefits and potential downsides of follow-up; feelings about changes to frequency of follow-up, and patient-centred recommendations for improving follow-up care. Methods Qualitative analysis of 29 in-depth interviews conducted with Australian patients undergoing long-term follow-up after surgical treatment of stage I/II melanoma. Results Patient-perceived benefits of follow-up included reassurance, early detection of new melanomas and non-melanoma skin cancers, education about skin self-examination, the opportunity to ask questions, and reinforcement of ‘sunsafe’ behaviours. Downsides included anxiety leading up to and during follow-up visits; inconvenience of travel to attend visits; and lost work time. Patients varied in their engagement with skin self-examination, and their views on multiple skin excisions, but highly valued access to specialists for unscheduled visits. Most patients felt their follow-up intervals could be extended to 12 months if recommended by their clinician. Conclusion The benefits and potential downsides of follow-up should be discussed with patients when deciding on a melanoma follow-up plan to achieve a balance between inducing additional patient anxiety and providing reassurance. Follow-up intervals of 12 months appear to be acceptable to patients

Sideband cooling of small ion Coulomb crystals in a Penning trap

We have recently demonstrated the laser cooling of a single 40 Ca + ion to the motional ground state in a Penning trap using the resolved-sideband cooling technique on the electric quadrupole transition S 1/2 ↔ D 5/2 . Here we report on the extension of this technique to small ion Coulomb crystals made of two or three 40 Ca + ions. Efficient cooling of the axial motion is achieved outside the Lamb-Dicke regime on a two-ion string along the magnetic field axis as well as on two- and three-ion planar crystals. Complex sideband cooling sequences are required in order to cool both axial degrees of freedom simultaneously. We measure a mean excitation after cooling of n COM for the centre of mass (COM) mode and n B for the breathing mode of the two-ion string with corresponding heating rates of 11(2)s -1 and 1(1)s -1 at a trap frequency of 162 kHz. The occupation of the ground state of the axial modes (n tilt = n COM = 0) is above 75% for the two-ion planar crystal and the associated heating rates 0.8(5)s -1 at a trap frequency of 355 kHz

Control of the conformations of ion Coulomb crystals in a Penning trap

Laser-cooled atomic ions form ordered structures in radiofrequency ion traps and in Penning traps. Here we demonstrate in a Penning trap the creation and manipulation of a wide variety of ion Coulomb crystals formed from small numbers of ions. The configuration can be changed from a linear string, through intermediate geometries, to a planar structure. The transition from a linear string to a zigzag geometry is observed for the first time in a Penning trap. The conformations of the crystals are set by the applied trap potential and the laser parameters, and agree with simulations. These simulations indicate that the rotation frequency of a small crystal is mainly determined by the laser parameters, independent of the number of ions and the axial confinement strength. This system has potential applications for quantum simulation, quantum information processing and tests of fundamental physics models from quantum field theory to cosmology