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We develop methods for constructing explicit generators, modulo torsion, of the $K_3$-groups of imaginary quadratic number fields. These methods are based on either tessellations of hyperbolic $3$-space or on direct calculations in suitable pre-Bloch groups and lead to the very first proven examples of explicit generators, modulo torsion, of any infinite $K_3$-group of a number field. As part of this approach, we make several improvements to the theory of Bloch groups for $ K_3 $ of any field, predict the precise power of $2$ that should occur in the Lichtenbaum conjecture at $ -1 $ and prove that this prediction is valid for all abelian number fields.
Jones et al's review of the assessment and management of the neuropsychiatric manifestations of Parkinson's disease serves as a practical guide to clinicians. This commentary outlines some of the underlying neuroscience and psychological sequelae of this range of conditions, offering a takeaway message to the clinician with an interest in Parkinson's neuropsychiatry.
Patients with psychiatric illness present a unique challenge to clinicians: in contrast to the traditional medical model, in which patients are conceptualised as being stricken by a disease, patients with certain psychiatric illnesses may seem complicit in the illness. Questions of free will, choice and the role of the physician can cause clinicians to feel helpless, disinterested or even resentful. These tensions are a lasting legacy of centuries of mind–body dualism. Over the past several decades, modern tools have finally allowed us to break down this false dichotomy. Integrating a modern neuroscience perspective into practice allows clinicians to conceptualise individuals with psychiatric illness in a way that promotes empathy and enhances patient care. Specifically, a strong grasp of neuroscience prevents clinicians from falling into the trap in which behavioural aspects of a patient's presentation are perceived as being separate from the disease process. We demonstrate the value of incorporating neuroscience into a biopsychosocial formulation through the example of a ‘difficult patient’.
Lewy body dementia, consisting of both dementia with Lewy bodies (DLB) and Parkinson's disease dementia (PDD), is considerably under-recognised clinically compared with its frequency in autopsy series.
This study investigated the clinical diagnostic pathways of patients with Lewy body dementia to assess if difficulties in diagnosis may be contributing to these differences.
We reviewed the medical notes of 74 people with DLB and 72 with non-DLB dementia matched for age, gender and cognitive performance, together with 38 people with PDD and 35 with Parkinson's disease, matched for age and gender, from two geographically distinct UK regions.
The cases of individuals with DLB took longer to reach a final diagnosis (1.2 v. 0.6 years, P = 0.017), underwent more scans (1.7 v. 1.2, P = 0.002) and had more alternative prior diagnoses (0.8 v. 0.4, P = 0.002), than the cases of those with non-DLB dementia. Individuals diagnosed in one region of the UK had significantly more core features (2.1 v. 1.5, P = 0.007) than those in the other region, and were less likely to have dopamine transporter imaging (P < 0.001). For patients with PDD, more than 1.4 years prior to receiving a dementia diagnosis: 46% (12 of 26) had documented impaired activities of daily living because of cognitive impairment, 57% (16 of 28) had cognitive impairment in multiple domains, with 38% (6 of 16) having both, and 39% (9 of 23) already receiving anti-dementia drugs.
Our results show the pathway to diagnosis of DLB is longer and more complex than for non-DLB dementia. There were also marked differences between regions in the thresholds clinicians adopt for diagnosing DLB and also in the use of dopamine transporter imaging. For PDD, a diagnosis of dementia was delayed well beyond symptom onset and even treatment.
Previous work suggests low intakes of fruit and vegetables (FV) across the world, poor knowledge of the details of FV recommendations, and associations between the two. This work aimed to develop an interactive mobile phone application (app) to facilitate adherence to the UK 5-a-day FV recommendations, and reports on the findings and feedback from the first test of the prototype.
Materials and Methods
Requirements for the app were first gained from previous research and potential end-users via four public engagement workshops, and prioritised using the MoSCoW method. A prototype app was then designed and developed using an agile approach. The prototype app was then tested in a randomized controlled pilot trial for impacts on FV knowledge and FV intake. Ninety-four adult volunteers were randomized to either receive (N = 50) or not receive the app (N = 44) for two or four weeks, and FV knowledge, self-report FV intakes, and FV behaviour (complimentary drink choice), were assessed at study start and study end. App use and feedback were also investigated.
Low knowledge of the FV recommendations centred around portion sizes and the need for variety, and an interactive mobile phone app was considered a suitable tool for improving knowledge in a practical manner, that would be available both at time of consumption and outside of these times. Findings revealed improved FV behaviour in volunteers who received the app for two weeks at study end: 16 app users chose a fruit drink, compared to 4 app users who chose a non-fruit drink, where 4 control volunteers also chose a fruit drink and 6 control volunteers chose a non-fruit drink. App users also suggested increased FV intakes, but changes were small, and possibly masked in questionnaire measures. Improvements in FV knowledge (of approx. 10%) were also found, but with no differences between groups. App usage was low and feedback suggested a desire for reminder notifications and a wish to return to the input for a previous day due to forgetting. Increased awareness of low FV intakes was also offered as feedback.
Our prototype app was well received and of potential benefit. A final version of the app was subsequently developed incorporating the findings and feedback from the pilot test. Improvements in the final version of the app include a message to increase awareness of low intakes and an option to add notifications to increase use. Testing of the final app is now needed.
We investigate the Galois structures of $p$-adic cohomology groups of general $p$-adic representations over finite extensions of number fields. We show, in particular, that as the field extensions vary over natural families the Galois modules formed by these cohomology groups always decompose as the direct sum of a projective module and a complementary module of bounded $p$-rank. We use this result to derive new (upper and lower) bounds on the changes in ranks of Selmer groups over extensions of number fields and descriptions of the explicit Galois structures of natural arithmetic modules.
The notion of creating artificial vision using visual prostheses has been
well represented though science fiction literature and films. When we think
of retinal prostheses, we immediately think of fictional characters like The
Terminator scanning across a bar to assess patrons for appropriately fitting
clothing, or Star Trek’s Geordi La Forge with his VISOR, a visual
instrument and sensory organ replacement placed across his eyes and attached
into his temples to provide him with vision. Such devices are no longer
farfetched. In the past 20 years, significant research has been undertaken
across the globe in the race for a “Bionic Eye”. Advances in
Bionic Eye research have come from improvements in the design and
fabrication of multielectrode arrays (MEAs) for medical applications. MEAs
are already commonplace in medicine with use in applications such as the
cochlear device, cardiac pacemakers, and deep brain stimulators where
interfacing with neuronal cell populations is required.
The use of MEAs for vision prostheses is currently of significant interest.
For the most part, retinal prostheses have dominated the research landscape
owing to the ease of access and direct contact to the retinal ganglion nerve
cells. However, MEAs are also in use for direct stimulation into the optic
nerve . Retinal prostheses bypass the damaged photoreceptor cells within
the retina and instead replace the degenerate retina with electrical
stimulation to the nerve cells. Using electrical stimulation, stimulated
retinal ganglion cells have been shown to elicit a percept in the form of a
phosphene in blind patients [2–6]. Accordingly, the two diseases
commonly linked to the justification for Bionic Eye research are age-related
macular degeneration (AMD) and retinitis pigmentosa (RP), diseases which
lead to progressive loss of photoreceptor cells and diseases where the
patient has had previous vision and thus exhibits prior visual-brain
pathways. At present, there has been no reliable cure for any of the retinal
diseases that target the photoreceptor cells, and thus the development of
prosthetic devices is a viable clinical treatment option [7–9].
White matter disruptions have been identified in individuals with congenital heart disease (CHD). However, no specific theory-driven relationships between microstructural white matter disruptions and cognition have been established in CHD. We conducted a two-part study. First, we identified significant differences in fractional anisotropy (FA) of emerging adults with CHD using Tract-Based Spatial Statistics (TBSS). TBSS analyses between 22 participants with CHD and 18 demographically similar controls identified five regions of normal appearing white matter with significantly lower FA in CHD, and two higher. Next, two regions of lower FA in CHD were selected to examine theory-driven differential relationships with cognition: voxels along the left uncinate fasciculus (UF; a tract theorized to contribute to verbal memory) and voxels along the right middle cerebellar peduncle (MCP; a tract previously linked to attention). In CHD, a significant positive correlation between UF FA and memory was found, r(20)=.42, p=.049 (uncorrected). There was no correlation between UF and auditory attention span. A positive correlation between MCP FA and auditory attention span was found, r(20)=.47, p=.027 (uncorrected). There was no correlation between MCP and memory. In controls, no significant relationships were identified. These results are consistent with previous literature demonstrating lower FA in younger CHD samples, and provide novel evidence for disrupted white matter integrity in emerging adults with CHD. Furthermore, a correlational double dissociation established distinct white matter circuitry (UF and MCP) and differential cognitive correlates (memory and attention span, respectively) in young adults with CHD. (JINS, 2015, 21, 22–33)
Disparities in access to medical care and outcomes of medical treatment related to insurance status are documented. However, little attention has been given to the effect of health care funding status on outcomes in trauma patients.
This study evaluated if adult trauma patients who arrived by air transport to a trauma center had different clinical outcomes based on their health insurance status.
A retrospective analysis was performed of all adult trauma patients arriving by prehospital flight services to a Level I Trauma Center over a 5-year period. Patients were classified as unfunded or funded based on health insurance status. Injury severity scores (ISS) were compared, while the end points evaluated in the study included duration of stay in the intensive care unit (ICU), duration of hospitalization, and mortality.
A total of 1,877 adult patients met inclusion criteria for the study, with 14% (n = 259) classified as unfunded and 86% (n = 1,618) classified as funded. Unfunded patients compared to funded patients had a significantly lower average ISS (12.82 vs 15.56; P < .001) but a significantly higher mortality rate (16.6% vs 10.7%; P < .01) and a 1.54 relative risk of death (95% CI, 1.136-2.098). Neither mean ICU stay (3.44 days vs 4.98 days; P = .264) nor duration of hospitalization (11.18 days vs 13.34 days; P = .382) was significantly different when controlling for ISS.
Unfunded health insurance status is associated with worse outcomes following less significant injury. Further investigation of baseline health disparities for identification and early intervention may improve outcomes. Additionally, these findings may have implications for the health systems of other countries that lack universal health care coverage.
GurienLA, ChesireDJ, KoonceSL, BurnsJBJr. An Evaluation of Trauma Outcomes Related to Insurance Status in Patients Requiring Prehospital Helicopter Transport. Prehosp Disaster Med. 2014;29(6):1-4.
This article is an executive summary of a report from the Centers for Disease Control and Prevention Ventilator-Associated Pneumonia Surveillance Definition Working Group, entitled “Developing a new, national approach to surveillance for ventilator-associated events” and published in Critical Care Medicine. The full report provides a comprehensive description of the Working Group process and outcome.
In September 2011, the Centers for Disease Control and Prevention (CDC) convened a Ventilator-Associated Pneumonia (VAP) Surveillance Definition Working Group to organize a formal process for leaders and experts of key stakeholder organizations to discuss the challenges of VAP surveillance definitions and to propose new approaches to VAP surveillance in adult patients (Table 1).
Using Burgers’ equation with mixed Neumann–Dirichlet boundary conditions, we highlight a
problem that can arise in the numerical approximation of nonlinear dynamical systems on
computers with a finite precision floating point number system. We describe the dynamical
system generated by Burgers’ equation with mixed boundary conditions, summarize some of
its properties and analyze the equilibrium states for finite dimensional dynamical systems
that are generated by numerical approximations of this system. It is important to note
that there are two fundamental differences between Burgers’ equation with mixed
Neumann–Dirichlet boundary conditions and Burgers’ equation with both Dirichlet boundary
conditions. First, Burgers’ equation with homogenous mixed boundary conditions on a finite
interval cannot be linearized by the Cole–Hopf transformation. Thus, on finite intervals
Burgers’ equation with a homogenous Neumann boundary condition is truly nonlinear. Second,
the nonlinear term in Burgers’ equation with a homogenous Neumann boundary condition is
not conservative. This structure plays a key role in understanding the complex dynamics
generated by Burgers’ equation with a Neumann boundary condition and how this structure
impacts numerical approximations. The key point is that, regardless of the particular
numerical scheme, finite precision arithmetic will always lead to numerically generated
equilibrium states that do not correspond to equilibrium states of the Burgers’ equation.
In this paper we establish the existence and stability properties of these numerical
stationary solutions and employ a bifurcation analysis to provide a detailed mathematical
explanation of why numerical schemes fail to capture the correct asymptotic dynamics. We
extend the results in [E. Allen, J.A. Burns, D.S. Gilliam, J. Hill and V.I. Shubov,
Math. Comput. Modelling 35 (2002) 1165–1195] and prove
that the effect of finite precision arithmetic persists in generating a nonzero numerical
false solution to the stationary Burgers’ problem. Thus, we show that the results obtained
in [E. Allen, J.A. Burns, D.S. Gilliam, J. Hill and V.I. Shubov, Math. Comput.
Modelling 35 (2002) 1165–1195] are not dependent on a specific
time marching scheme, but are generic to all convergent numerical approximations of