11,498 research outputs found
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A pilot study of a text messaging intervention to modify illness and medication beliefs amongst patients diagnosed with inflammatory bowel disease
Intentional and unintentional medication non-adherence is a particular challenge for patients with inflammatory bowel disease (IBD). Non-adherence can affect patientsâ quality of life, which can result in unfavorable treatment outcomes, more hospitalizations, and higher healthcare-related costs. The purpose of this study was to assess whether a tailored text message intervention designed to modify illness and medication adherence beliefs in patients with IBD would increase treatment compliance and change patientsâ illness perceptions and medication concerns. This pilot study utilized a pre-test-post-test non-randomized design. A sample of 32 IBD patients was recruited within the UK. Participantsâ medication beliefs and illness perception scores determined the set of tailored daily text messages, which were sent to patients over duration of 12 weeks. Medication adherence increased post-intervention, as âforgetting to take medicationâ decreased while âneverâ forgetting to take medication increased over time. A significant increase in treatment control and coherence and a decreased level of concern surrounding their condition was evident. Participantsâ level of concern towards their medications changed during the 12 weeks, with a baseline mean concern score of 3.08 (.57) in comparison to the 12 weeks mean concern score of 2.89 (.59), which is statistically different, t (31)â=â2.16, pâ<â.038, râ=â.36 (medium effect). Sixty-six percent of participants from the baseline were aware of the necessity of their medication: âwithout my medication I would become ill.â The results have direct implications for improving medication adherence and changing illness and medication beliefs. This study validated the benefits of text messages and highlighted the importance of addressing these beliefs in order to understand the reasons for non-adherence fully
Entanglement distribution by an arbitrarily inept delivery service
We consider the scenario where a company C manufactures in bulk pure
entangled pairs of particles, each pair intended for a distinct pair of distant
customers. Unfortunately, its delivery service is inept - the probability that
any given customer pair receives its intended particles is S, and the customers
cannot detect whether an error has occurred. Remarkably, no matter how small S
is, it is still possible for C to distribute entanglement by starting with
non-maximally entangled pairs. We determine the maximum entanglement
distributable for a given S, and also determine the ability of the parties to
perform nonlocal tasks with the qubits they receive.Comment: 5 pages, 3 figures. v2 includes minor change
Sharing Polarization within Quantum Subspaces
Given an ensemble of n spins, at least some of which are partially polarized,
we investigate the sharing of this polarization within a subspace of k spins.
We assume that the sharing results in a pseudopure state, characterized by a
single purity parameter which we call the bias. As a concrete example we
consider ensembles of spin-1/2 nuclei in liquid-state nuclear magnetic
resonance (NMR) systems. The shared bias levels are compared with some current
entanglement bounds to determine whether the reduced subspaces can give rise to
entangled states.Comment: 7 pages, 3 figure
Entanglement and Symmetry: A Case Study in Superselection Rules, Reference Frames, and Beyond
This paper concentrates on a particular example of a constraint imposed by
superselection rules (SSRs): that which applies when the parties (Alice and
Bob) cannot distinguish among certain quantum objects they have. This arises
naturally in the context of ensemble quantum information processing such as in
liquid NMR. We discuss how a SSR for the symmetric group can be applied, and
show how the extractable entanglement can be calculated analytically in certain
cases, with a maximum bipartite entanglement in an ensemble of N Bell-state
pairs scaling as log(N) as N goes to infinity . We discuss the apparent
disparity with the asymptotic (N >> 1) recovery of unconstrained entanglement
for other sorts of superselection rules, and show that the disparity disappears
when the correct notion of applying the symmetric group SSR to multiple copies
is used. Next we discuss reference frames in the context of this SSR, showing
the relation to the work of von Korff and Kempe [Phys. Rev. Lett. 93, 260502
(2004)]. The action of a reference frame can be regarded as the analog of
activation in mixed-state entanglement. We also discuss the analog of
distillation: there exist states such that one copy can act as an imperfect
reference frame for another copy. Finally we present an example of a stronger
operational constraint, that operations must be non-collective as well as
symmetric. Even under this stronger constraint we nevertheless show that
Bell-nonlocality (and hence entanglement) can be demonstrated for an ensemble
of N Bell-state pairs no matter how large N is. This last work is a
generalization of that of Mermin [Phys. Rev. D 22, 356 (1980)].Comment: 16 pages, 6 figures. v2 updated version published in Phys Rev
Global Optical Control of a Quantum Spin Chain
Quantum processors which combine the long decoherence times of spin qubits
together with fast optical manipulation of excitons have recently been the
subject of several proposals. I show here that arbitrary single- and entangling
two-qubit gates can be performed in a chain of perpetually coupled spin qubits
solely by using laser pulses to excite higher lying states. It is also
demonstrated that universal quantum computing is possible even if these pulses
are applied {\it globally} to a chain; by employing a repeating pattern of four
distinct qubit units the need for individual qubit addressing is removed. Some
current experimental qubit systems would lend themselves to implementing this
idea.Comment: 5 pages, 3 figure
Geometric Aspects of Composite Pulses
Unitary operations acting on a quantum system must be robust against
systematic errors in control parameters for reliable quantum computing.
Composite pulse technique in nuclear magnetic resonance (NMR) realises such a
robust operation by employing a sequence of possibly poor quality pulses. In
this article, we demonstrate that two kinds of composite pulses, one
compensates for a pulse length error in a one-qubit system and the other
compensates for a J-coupling error in a twoqubit system, have vanishing
dynamical phase and thereby can be seen as geometric quantum gates, which
implement unitary gates by the holonomy associated with dynamics of cyclic
vectors defined in the text.Comment: 20 pages, 4 figures. Accepted for publication in Philosophical
Transactions of the Royal Society
Implementation of quantum gates based on geometric phases accumulated in the eigenstates of periodic invariant operators
We propose a new strategy to physically implement a universal set of quantum
gates based on geometric phases accumulated in the nondegenerate eigenstates of
a designated invariant operator in a periodic physical system. The system is
driven to evolve in such a way that the dynamical phase shifts of the invariant
operator eigenstates are the same (or {\it mod} ) while the corresponding
geometric phases are nontrivial.
We illustrate how this strategy to work in a simple but typical NMR-type
qubit system.Comment: 4 page
Practical Implementations of Twirl Operations
Twirl operations, which convert impure singlet states into Werner states,
play an important role in many schemes for entanglement purification. In this
paper we describe strategies for implementing twirl operations, with an
emphasis on methods suitable for ensemble quantum information processors such
as nuclear magnetic resonance (NMR) quantum computers. We implement our twirl
operation on a general two-spin mixed state using liquid state NMR techniques,
demonstrating that we can obtain the singlet Werner state with high fidelity.Comment: 6 pages RevTex4 including 2 figures (fig 1 low quality to save space
Polarization Requirements for Ensemble Implementations of Quantum Algorithms with a Single Bit Output
We compare the failure probabilities of ensemble implementations of quantum
algorithms which use pseudo-pure initial states, quantified by their
polarization, to those of competing classical probabilistic algorithms.
Specifically we consider a class algorithms which require only one bit to
output the solution to problems. For large ensemble sizes, we present a general
scheme to determine a critical polarization beneath which the quantum algorithm
fails with greater probability than its classical competitor. We apply this to
the Deutsch-Jozsa algorithm and show that the critical polarization is 86.6%.Comment: 11 pages, 3 figure
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Mental Health and Wellbeing Briefing Paper
Good mental health is recognised as an integral part of a personÊŒs wellbeing, embedded in all aspects of their whole life, their beliefs, faith, culture, environment, spirituality, work, housing, education, family and community respect. Mental ill-health is the largest single source of burden of disease in the UK. Almost 23% of the total burden of disease in the UK is attributable to mental disorders, compared to 16.2% for cardiovascular disease and 15.9% for cancer. 1 in 4 families worldwide is likely to have at least one member experiencing mental ill health or behavioural difficulties. People in marginalised groups are at greater risk of mental health problems, including people from Black, Asian and other minority ethnic backgrounds, lesbian, gay, bisexual and transgender people, disabled people and people who have had contact with the criminal justice system, among others.
Evidence shows that prior to the COVID-19 pandemic Black and ethnic minority communities were disproportionately at higher risk of exacerbating mental health inequalities, and were unequally impacted by social determinants associated with mental ill health. Barriers to accessing mental health support and the role of cultural beliefs and attitudes have been cited as explanations for existing mental health inequalities that face Black and ethnic minority communities living in the UK. Black and ethnic minority communities, especially Black and South Asian groups experience more adverse pathways to care, higher rates of compulsory admission and treatment, more contact with the police and criminal justice agencies and poorer longer-term outcomes compared with White British people.
Although this was known prior to the pandemic, these disparities have been amplified and exacerbated, significantly affecting Black and ethnic minority populations who already had low access to mental health care. Yet large proportions of this population are unable to access treatment for mental health care. The Centre for Mental HealthÊŒs report5 on understanding inequalities in mental health during the pandemic is a call to action for policymakers and health professional to improve mental health equality amongst Black and ethnic minority communities, by providing emergency funding for mental health organisations that have adapted their services to be culturally responsive. We have to also focus on the structural conditions that overwhelmingly and disproportionately affect Black and ethnic minority communities such as precarious housing, employment, and political and environmental stressors
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