187 research outputs found
Image-Guided Abdominal Surgery and Therapy Delivery
ABSTRACT Image-Guided Surgery has become the standard of care in intracranial neurosurgery providing more exact resections while minimizing damage to healthy tissue. Moving that process to abdominal organs presents additional challenges in the form of image segmentation, image to physical space registration, organ motion and deformation. In this paper, we present methodologies and results for addressing these challenges in two specific organs: the liver and the kidney
Kondo effect in quantum dots
We review mechanisms of low-temperature electronic transport through a
quantum dot weakly coupled to two conducting leads. Transport in this case is
dominated by electron-electron interaction. At temperatures moderately lower
than the charging energy of the dot, the linear conductance is suppressed by
the Coulomb blockade. Upon further lowering of the temperature, however, the
conductance may start to increase again due to the Kondo effect. We concentrate
on lateral quantum dot systems and discuss the conductance in a broad
temperature range, which includes the Kondo regime
Observation of a kilogram-scale oscillator near its quantum ground state
We introduce a novel cooling technique capable of approaching the quantum ground state of a kilogram-scale system—an interferometric gravitational wave detector. The detectors of the Laser Interferometer Gravitational-wave Observatory (LIGO) operate within a factor of 10 of the standard quantum limit (SQL), providing a displacement sensitivity of 10[superscript −18] m in a 100 Hz band centered on 150 Hz. With a new feedback strategy, we dynamically shift the resonant frequency of a 2.7 kg pendulum mode to lie within this optimal band, where its effective temperature falls as low as 1.4 μK, and its occupation number reaches about 200 quanta. This work shows how the exquisite sensitivity necessary to detect gravitational waves can be made available to probe the validity of quantum mechanics on an enormous mass scale.Alfred P. Sloan FoundationUnited States. National Aeronautics and Space AdministrationDavid & Lucile Packard FoundationResearch CorporationNational Science Foundation (U.S.
Quantum state preparation and macroscopic entanglement in gravitational-wave detectors
Long-baseline laser-interferometer gravitational-wave detectors are operating
at a factor of 10 (in amplitude) above the standard quantum limit (SQL) within
a broad frequency band. Such a low classical noise budget has already allowed
the creation of a controlled 2.7 kg macroscopic oscillator with an effective
eigenfrequency of 150 Hz and an occupation number of 200. This result, along
with the prospect for further improvements, heralds the new possibility of
experimentally probing macroscopic quantum mechanics (MQM) - quantum mechanical
behavior of objects in the realm of everyday experience - using
gravitational-wave detectors. In this paper, we provide the mathematical
foundation for the first step of a MQM experiment: the preparation of a
macroscopic test mass into a nearly minimum-Heisenberg-limited Gaussian quantum
state, which is possible if the interferometer's classical noise beats the SQL
in a broad frequency band. Our formalism, based on Wiener filtering, allows a
straightforward conversion from the classical noise budget of a laser
interferometer, in terms of noise spectra, into the strategy for quantum state
preparation, and the quality of the prepared state. Using this formalism, we
consider how Gaussian entanglement can be built among two macroscopic test
masses, and the performance of the planned Advanced LIGO interferometers in
quantum-state preparation
Supporting carers to manage pain medication in cancer patients at the end of life: A feasibility trial
Background:
Carers of people with advanced cancer play a significant role in managing pain medication, yet they report insufficient information and support to do so confidently and competently. There is limited research evidence on the best ways for clinicians to help carers with medication management.
Aims:
To develop a pain medicines management intervention (Cancer Carers Medicines Management) for cancer patients’ carers near the end of life and evaluate feasibility and acceptability to nurses and carers. To test the feasibility of trial research procedures and to inform decisions concerning a full-scale randomised controlled trial.
Design:
Phase I-II clinical trial. A systematic, evidence-informed participatory method was used to develop CCMM: a nurse-delivered structured conversational process. A two-arm, cluster randomised controlled feasibility trial of Cancer Carers Medicines Management was conducted, with an embedded qualitative study to evaluate participants’ experiences of Cancer Carers Medicines Management and trial procedures.
Setting:
Community settings in two study sites.
Participants:
Phase I comprises 57 carers, patients and healthcare professionals and Phase II comprises 12 nurses and 15 carers.
Results:
A novel intervention was developed. Nurses were recruited and randomised. Carer recruitment to the trial was problematic with fewer than predicted eligible participants, and nurses judged a high proportion unsuitable to recruit into the study. Attrition rates following recruitment were typical for the study population. Cancer Carers Medicines Management was acceptable to carers and nurses who took part, and some benefits were identified.
Conclusion:
Cancer Carers Medicines Management is a robustly developed medicines management intervention which merits further research to test its effectiveness to improve carers’ management of pain medicines with patients at the end of life. The study highlighted aspects of trial design that need to be considered in future research
Understanding how perceptions of tobacco constituents and the FDA relate to effective and credible tobacco risk messaging: A national phone survey of U.S. adults, 2014–2015
As reported in the original paper [1], the Center for Regulatory
Research on Tobacco Communication conducted a
telephone survey in 2014–2015 with a national sample of
adults ages 18 and older living in the United States
(N = 5014). Poverty level was determined using the household
size and income reported by the respondents and
applying the federal poverty numbers available from the
U.S. Department of Health and Human Services in 2014.
A coding error was made during the data recoding process
such that 2.7% of respondents (n = 129) were incorrectly
classified as living above the poverty line. Below are
updated Tables 1, 2 and 4 presenting both the original and
corrected estimates. No substantive conclusions reported
in the paper were affected by this correction
Determination of Leptoquark Properties in Polarized Collisions
We study leptoquark production using polarized colliders for the
center of mass energies ~GeV and 1~TeV. We show that using
polarization asymmetries the ten different types of leptoquarks listed by
Buchm\"uller, R\"uckl and Wyler can be distinquished from one another for
leptoquark masses essentially up to the kinematic limit of the respective
colliders. Thus, if a leptoquark were discovered an collider could
play a crucial role in determining its origins.Comment: 10 pages (plus 10 postscript figures submitted separately), OCIP/C
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The protocols for the 10/66 dementia research group population-based research programme
BACKGROUND: Latin America, China and India are experiencing unprecedentedly rapid demographic ageing with an increasing number of people with dementia. The 10/66 Dementia Research Group's title refers to the 66% of people with dementia that live in developing countries and the less than one tenth of population-based research carried out in those settings. This paper describes the protocols for the 10/66 population-based and intervention studies that aim to redress this imbalance. METHODS/DESIGN: Cross-sectional comprehensive one phase surveys have been conducted of all residents aged 65 and over of geographically defined catchment areas in ten low and middle income countries (India, China, Nigeria, Cuba, Dominican Republic, Brazil, Venezuela, Mexico, Peru and Argentina), with a sample size of between 1000 and 3000 (generally 2000). Each of the studies uses the same core minimum data set with cross-culturally validated assessments (dementia diagnosis and subtypes, mental disorders, physical health, anthropometry, demographics, extensive non communicable disease risk factor questionnaires, disability/functioning, health service utilisation, care arrangements and caregiver strain). Nested within the population based studies is a randomised controlled trial of a caregiver intervention for people with dementia and their families (ISRCTN41039907; ISRCTN41062011; ISRCTN95135433; ISRCTN66355402; ISRCTN93378627; ISRCTN94921815). A follow up of 2.5 to 3.5 years will be conducted in 7 countries (China, Cuba, Dominican Republic, Venezuela, Mexico, Peru and Argentina) to assess risk factors for incident dementia, stroke and all cause and cause-specific mortality; verbal autopsy will be used to identify causes of death. DISCUSSION: The 10/66 DRG baseline population-based studies are nearly complete. The incidence phase will be completed in 2009. All investigators are committed to establish an anonymised file sharing archive with monitored public access. Our aim is to create an evidence base to empower advocacy, raise awareness about dementia, and ensure that the health and social care needs of older people are anticipated and met
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