285 research outputs found
Effects of Vacuum Fluctuation Suppression on Atomic Decay Rates
The use of atomic decay rates as a probe of sub-vacuum phenomena will be
studied. Because electromagnetic vacuum fluctuations are essential for
radiative decay of excited atomic states, decay rates can serve as a measure of
the suppression of vacuum fluctuation in non-classical states, such as squeezed
vacuum states. In such states the renormalized expectation value of the square
of the electric field or the energy density can be periodically negative,
representing suppression of vacuum fluctuations. We explore the extent to which
atomic decays can be used to measure the mean squared electric field or energy
density. We consider a scheme in which atoms in an excited state transit a
closed cavity whose lowest mode contains photons in a non-classical state. The
change in the decay probability of the atom in the cavity due to the
non-classical state can, under certain circumstances, serve as a measure of the
mean squared electric field or energy density in the cavity. We derive a
quantum inequality bound on the decrease in this probability. We also show that
the decrease in decay rate can sometimes be a measure of negative energy
density or negative squared electric field. We make some estimates of the
magnitude of this effect, which indicate that an experimental test might be
possible.Comment: 19 pages, 3 figure
Electromagnetic Casimir densities for a wedge with a coaxial cylindrical shell
Vacuum expectation values of the field square and the energy-momentum tensor
for the electromagnetic field are investigated for the geometry of a wedge with
a coaxal cylindrical boundary. All boundaries are assumed to be perfectly
conducting and both regions inside and outside the shell are considered. By
using the generalized Abel-Plana formula, the vacuum expectation values are
presented in the form of the sum of two terms. The first one corresponds to the
geometry of the wedge without the cylindrical shell and the second term is
induced by the presence of the shell. The vacuum energy density induced by the
shell is negative for the interior region and is positive for the exterior
region. The asymptotic behavior of the vacuum expectation values are
investigated in various limiting cases. It is shown that the vacuum forces
acting on the wedge sides due to the presence of the cylindrical boundary are
always attractive.Comment: 21 pages, 7 figure
Vacuum local and global electromagnetic self-energies for a point-like and an extended field source
We consider the electric and magnetic energy densities (or equivalently field
fluctuations) in the space around a point-like field source in its ground
state, after having subtracted the spatially uniform zero-point energy terms,
and discuss the problem of their singular behavior at the source's position. We
show that the assumption of a point-like source leads, for a simple Hamiltonian
model of the interaction of the source with the electromagnetic radiation
field, to a divergence of the renormalized electric and magnetic energy density
at the position of the source. We analyze in detail the mathematical structure
of such singularity in terms of a delta function and its derivatives. We also
show that an appropriate consideration of these singular terms solves an
apparent inconsistency between the total field energy and the space integral of
its density. Thus the finite field energy stored in these singular terms gives
an important contribution to the self-energy of the source. We then consider
the case of an extended source, smeared out over a finite volume and described
by an appropriate form factor. We show that in this case all divergences in
local quantities such as the electric and the magnetic energy density, as well
as any inconsistency between global and space-integrated local self-energies,
disappear.Comment: 8 pages. The final publication is available at link.springer.co
Estradiol and progesterone fecal metabolites analysis in crab-eating-fox (Cerdocyoun thous)
Spectral Line Selection for HMI: A Comparison of Fe I 6173 and Ni I 6768
We present a study of two spectral lines, Fe I 6173 Angstroms and Ni I 6768
Angstroms, that were candidates to be used in the Helioseismic and Magnetic
Imager (HMI) for observing Doppler velocity and the vector magnetic field. The
line profiles were studied using the Mt. Wilson Observatory, the Advanced
Stokes Polarimeter and the Kitt Peak McMath telescope and one meter Fourier
transform spectrometer atlas. Both Fe I and Ni I profiles have clean continua
and no blends that threaten instrument performance. The Fe I line is 2% deeper,
15% narrower and has a 6% smaller equivalent width than the Ni I line. The
potential of each spectral line to recover pre-assigned solar conditions is
tested using a least-squares minimization technique to fit Milne-Eddington
models to tens of thousands of line profiles that have been sampled at five
spectral positions across the line. Overall, the Fe I line has a better
performance than the Ni I line for vector magnetic field retrieval. We selected
the Fe I spectral line for use in HMI due to its better performance for
magnetic diagnostics while not sacrificing velocity information
First measurement of direct photoproduction on the proton
We report on the results of the first measurement of exclusive
meson photoproduction on protons for GeV and GeV. Data were collected with the CLAS detector at the Thomas
Jefferson National Accelerator Facility. The resonance was detected via its
decay in the channel by performing a partial wave analysis of the
reaction . Clear evidence of the meson
was found in the interference between and waves at GeV. The -wave differential cross section integrated in the mass range of
the was found to be a factor of 50 smaller than the cross section
for the meson. This is the first time the meson has been
measured in a photoproduction experiment
A randomised controlled trial of acceptance and commitment therapy plus usual care compared to usual care alone for improving psychological health in people with motor neuron disease (COMMEND): study protocol
Background
Motor neuron disease (MND) is a rapidly progressive, fatal neurodegenerative disease that predominantly affects motor neurons from the motor cortex to the spinal cord and causes progressive wasting and weakening of bulbar, limb, abdominal and thoracic muscles. Prognosis is poor and median survival is 2â3 years following symptom onset. Psychological distress is relatively common in people living with MND. However, formal psychotherapy is not routinely part of standard care within MND Care Centres/clinics in the UK, and clear evidence-based guidance on improving the psychological health of people living with MND is lacking. Previous research suggests that Acceptance and Commitment Therapy (ACT) may be particularly suitable for people living with MND and may help improve their psychological health.
Aims
To assess the clinical and cost-effectiveness of ACT modified for MND plus usual multidisciplinary care (UC) in comparison to UC alone for improving psychological health in people living with MND.
Methods
The COMMEND trial is a multi-centre, assessor-blind, parallel, two-arm RCT with a 10-month internal pilot phase. 188 individuals agedââ„â18 years with a diagnosis of definite, laboratory-supported probable, clinically probable, or possible familial or sporadic amyotrophic lateral sclerosis, and additionally the progressive muscular atrophy and primary lateral sclerosis variants, will be recruited from approximately 14 UK-based MND Care Centres/clinics and via self-referral. Participants will be randomly allocated to receive up to eight 1:1 sessions of ACT plus UC or UC alone by an online randomisation system. Participants will complete outcome measures at baseline and at 6- and 9-months post-randomisation. The primary outcome will be quality of life at six months. Secondary outcomes will include depression, anxiety, psychological flexibility, health-related quality of life, adverse events, ALS functioning, survival at nine months, satisfaction with therapy, resource use and quality-adjusted life years. Primary analyses will be by intention to treat and data will be analysed using multi-level modelling.
Discussion
This trial will provide definitive evidence on the clinical and cost-effectiveness of ACT plus UC in comparison to UC alone for improving psychological health in people living with MND
A global call for action to include gender in research impact assessment
Global investment in biomedical research has grown significantly over the last decades, reaching approximately a quarter of a trillion US dollars in 2010. However, not all of this investment is distributed evenly by gender. It follows, arguably, that scarce research resources may not be optimally invested (by either not supporting the best science or by failing to investigate topics that benefit women and men equitably). Women across the world tend to be significantly underrepresented in research both as researchers and research participants, receive less research funding, and appear less frequently than men as authors on research publications. There is also some evidence that women are relatively disadvantaged as the beneficiaries of research, in terms of its health, societal, and economic impacts. Historical gender biases may have created a path dependency that means that the research system and the impacts of research are biased towards male researchers and male beneficiaries, making it inherently difficult (though not impossible) to eliminate gender bias. In this commentary, we â a group of scholars and practitioners from Africa, America, Asia, and Europeâ argue that gender-sensitive research impact assessment could become a force for good in moving science policy and practice towards gender equity. Research impact assessment is the multidisciplinary field of scientific inquiry that examines the research process to maximise scientific, societal, and economic returns on investment in research. It encompasses many theoretical and methodological approaches that can be used to investigate gender bias and recommend actions for change to maximise research impact. We offer a set of recommendations to research funders, research institutions, and research evaluators who conduct impact assessment on how to include and strengthen analysis of gender equity in research impact assessment and issue a global call for action
Acceptability, fidelity and trial experience of four intervention components to support medication adherence in women with breast cancer: A process evaluation protocol for a pilot fractional factorial trial
Background
The Refining and Optimising a behavioural intervention to Support Endocrine Therapy Adherence (ROSETA) programme has developed four intervention components aiming to improve medication adherence in women with early-stage breast cancer. These are (a) text messages, (b) information leaflet, (c) Acceptance and Commitment Therapy-based guided self-help (ACT), (d) side-effect management website. Guided by the Multiphase Optimisation Strategy, our pilot trial will use a fractional factorial design to evaluate the feasibility of undertaking a larger optimisation trial. The pilot will include a process evaluation to maximise learning regarding the fidelity and acceptability of the intervention components before proceeding with a larger trial. The trial process evaluation has three aims: to assess the (1) fidelity and (2) acceptability of the intervention components; and (3) to understand participantâs trial experience, and barriers and facilitators to recruitment and retention.
Methods
The process evaluation will use multiple methods. Fidelity of the intervention components will be assessed using self-reported questionnaire data, trial data on intervention component adherence, and observations of the ACT sessions. Acceptability of the intervention components and trial experience will be explored using an acceptability questionnaire and interviews with patients and trial therapists. Trial experience will be assessed using a questionnaire and interviews with participants, while barriers and facilitators to recruitment and retention will be assessed using a questionnaire completed by research nurses and participant interviews. The pilot trial opened for recruitment on 20th May 2022 and was open at the time of submission.
Conclusions
This process evaluation will provide information regarding whether the intervention components can be delivered with fidelity within a national healthcare setting and are acceptable to participants. We will also better understand participant experience in a pilot trial with a fractional factorial design, and any barriers and facilitators to recruitment and retention.
Registration
ISRCTN registry (ISRCTN10487576, 16/12/2021).
Plain English summary
The majority of women with early-stage breast cancer are recommended adjuvant endocrine therapy (AET) to reduce the chances of their cancer coming back. Many women given this medication donât take it every day or stop taking it earlier than they should. We have developed four different interventions to help women take AET. These are; text messages reminding women to take AET; an information leaflet explaining how AET works and its benefits and side-effects; a therapy programme to reduce distress, consisting of five support sessions and four module booklets; and a website with strategies to manage AET side-effects. We are now testing whether these interventions can be delivered within the NHS in different combinations, in a small trial.
We have three aims:
To find out if the interventions can be given and are received in the way they were supposed to (fidelity).
To find out if the support received as part of the trial was acceptable to women with breast cancer (acceptability).
To find out what womenâs experience was of taking part in the trial overall (trial experience).
To do this we will:
Interview participants to ask them how acceptable they found the interventions, what they understood, whether they used the interventions, and how they found participating in the trial.
Interview therapists who delivered the therapy programme to see if they delivered it as they were supposed to, and how they found delivering the intervention.
Ask participants to complete questionnaires about how acceptable the interventions were, and whether they read and used them.
Ask the staff involved in finding participants for the trial about challenges and improvements.
We will use what we find to make improvements in a future trial where we will test whether the interventions help women to take AET
Molecular Mechanism of the Constitutive Activation of the L250Q Human Melanocortin-4 Receptor Polymorphism â
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65471/1/j.1747-0285.2006.00362.x.pd
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