Virial mass in DGP brane cosmology

We study the virial mass discrepancy in the context of a DPG brane-world scenario and show that such a framework can offer viable explanations to account for the mass discrepancy problem. This is done by defining a geometrical mass $\mathcal{N}$ that we prove to be proportional to the virial mass. Estimating $\mathcal{N}$ using observational data, we show that it behaves linearly with $r$ and has a value of the order of $M_{200}$, pointing to a possible resolution of the virial mass discrepancy. We also obtain the radial velocity dispersion of galaxy clusters and show that it is compatible with the radial velocity dispersion profile of such clusters. This velocity dispersion profile can be used to differentiate various models predicting the virial mass.Comment: 12 pages, 1 figure, to appear in CQ

Investigations into the assembly behaviour of a 'rigidified': P-carboxylatocalix[4]arene

The p-carboxylatocalix[4]arenes have been shown to be versatile supramolecular building blocks capable of forming a range of bi-layers, capsules and nanoscale tubules in the solid state. Here we report the synthesis of a new 'rigidified' analogue, as well as investigations into its self-assembly and related coordination chemistry. These behaviours are reminiscent of other p-carboxylatocalix[4]arenes despite the presence of rigidifying groups at the lower-rim, suggesting that this building block may be further exploited in the assembly of a range of new metal-organic cages and coordination polymers

Feasibility and findings of electrocardiogram recording in older adults with intellectual disabilities:results of the Healthy Ageing and Intellectual Disabilities study

Background: Older adults with intellectual disabilities (ID) have a high risk of cardiovascular diseases (CVD). At the same time, challenging diagnostic work-up increases the likelihood of underdiagnosis of CVD in this population. To limit this underdiagnosis, it would be beneficial to use objective measures such as the electrocardiogram (ECG). However, little is known about the feasibility of ECG recording and the prevalence of ECG abnormalities in this population. Therefore, the aims of this study were to investigate the feasibility of resting ECG recording, to study the prevalence of ECG abnormalities, and to compare the frequency of ECG abnormalities with medical records in older adults with ID. Method: A cross-sectional study was performed within a cohort of older adults (≥60 years) with ID as part of the Healthy Ageing and Intellectual Disabilities (HA-ID) study. A resting 12-lead ECG was attempted, and the ECG recording was considered feasible if the recording could be made and if the ECG could be interpreted by a cardiologist and the Modular ECG Analysis System (MEANS). ECGs were assessed for the presence of ECG abnormalities and medical record review was performed. If the cardiologist or MEANS concluded that there was evidence of myocardial infarction, atrial fibrillation or QTc prolongation on the ECG in the absence of this ECG diagnosis in the participant's medical record, this was classified as a previously undiagnosed ECG diagnosis. Results: ECG recording was feasible in 134 of the 200 participants (67.0%). Of these 134 participants (70.6 ± 5.8 years; 52.2% female), 103 (76.9%) had one or more ECG abnormality, with the most prevalent being prolonged P-wave duration (27.6%), QTc prolongation (18.7%), minor T-wave abnormalities (17.9%), first degree atrioventricular block (12.7%) and myocardial infarction (6.7%). Eight out of 9 (88.9%) myocardial infarctions and all cases of (significant) QTc prolongation (100%) were previously undiagnosed. Conclusions: This study showed that ECG recording is feasible in the majority of older adults with ID and revealed a substantial underdiagnosis of ECG abnormalities. These results stress the importance of ECG recording and warrant further research into the yield of opportunistic ECG screening in older adults with ID.</p

Direct observation of molecular cooperativity near the glass transition

We describe direct observations of molecular cooperativity near the glass transition in poly-vinyl-acetate (PVAc), through nanometer-scale probing of dielectric fluctuations. Molecular clusters switched spontaneously between two to four distinct configurations, producing complex random-telegraph-signals (RTS). Analysis of the RTS and their power spectra shows that individual clusters exhibit both transient dynamical heterogeneity and non-exponential kinetics.Comment: 14 pages pdf, need Acrobat Reade

The role of Mental Health Care Act status in dignity-related complaints by psychiatric inpatients : a cross-sectional analytical study

BACKGROUND: Globally interest has grown in promoting the rights of patients, especially psychiatric patients. Two core elements of patients’ rights are the rights to be treated in a dignified manner and to give feedback about services. Psychiatric patients may feel treated in an undignified manner, especially during involuntary hospital admissions. AIM: We explored the relationship between Mental Health Care Act 17 of 2002 (MHCA) status and dignity-related complaints. SETTING: The study was conducted at a specialist state psychiatric hospital. METHODS: We reviewed 120 registered complaints by psychiatric inpatients, retrieved the clinical files, and analysed 70 complaints. Fisher’s exact tests described the relationship between patients’ MHCA status and the frequency of dignity-related or other categories of complaints. Logistic regression analyses were adjusted for potential covariates. RESULTS: Most complaints were from single, literate male patients, aged 30–39 years, with mood disorders. Most complainants were admitted involuntarily (60%). Dignity-related complaints (n = 41; 58%) outnumbered nondignity-related complaints (n = 29; 41%). The proportion of dignity-related complaints was higher in involuntary (64%) and assisted (60%) patients than in voluntary patients (44%). Dignity-related complaints were not significantly associated with MHCA status (χ2 = 2.03 and p = 0.36). Involuntary patients were more than twice as likely as assisted and voluntary patients to complain about dignity-related matters (Odds ratio [OR]: 2.25; 95% confidence interval [CI] [0.71; 7.13]; p = 0.16). CONCLUSION: Involuntary patients are more likely to complain about dignity-related matters. Qualitative research is recommended for a deeper understanding of patients’ experiences during admission.http://www.sajpsychiatry.orgPsychiatr

Atypical presentation of acute pancreatitis in a man with pancreatic insufficiency and cystic fibrosis: a case report

<p>Abstract</p> <p>Introduction</p> <p>Whether acute pancreatitis can occur in pancreatically insufficient individuals with cystic fibrosis remains a matter of debate.</p> <p>Case presentation</p> <p>We describe a case of acute pancreatitis occurring in a 52-year-old Caucasian Australian man with moderately severe cystic fibrosis lung disease and pancreatic insufficiency. An inflammatory mass within the head of his pancreas was confirmed using computed tomography, magnetic resonance imaging and pancreatic biopsy, but serum amylase and lipase remained normal throughout the acute phase of his illness. His symptoms and the pancreatic mass resolved following the insertion of a biliary stent and the introduction of ursodeoxycholic acid.</p> <p>Conclusion</p> <p>Our case report highlights the potential for acute pancreatitis to occur in patients with pancreatic insufficiency and cystic fibrosis. We further demonstrate that conventional biochemical markers that are normally assessed to confirm the diagnosis may not be of particular use. As patients with cystic fibrosis survive into their fourth and fifth decades of life, atypical presentations of acute pancreatitis may become more common.</p

Lattice dynamics and correlated atomic motion from the atomic pair distribution function

The mean-square relative displacements (MSRD) of atomic pair motions in crystals are studied as a function of pair distance and temperature using the atomic pair distribution function (PDF). The effects of the lattice vibrations on the PDF peak widths are modelled using both a multi-parameter Born von-Karman (BvK) force model and a single-parameter Debye model. These results are compared to experimentally determined PDFs. We find that the near-neighbor atomic motions are strongly correlated, and that the extent of this correlation depends both on the interatomic interactions and crystal structure. These results suggest that proper account of the lattice vibrational effects on the PDF peak width is important in extracting information on static disorder in a disordered system such as an alloy. Good agreement is obtained between the BvK model calculations of PDF peak widths and the experimentally determined peak widths. The Debye model successfully explains the average, though not detailed, natures of the MSRD of atomic pair motion with just one parameter. Also the temperature dependence of the Debye model largely agrees with the BvK model predictions. Therefore, the Debye model provides a simple description of the effects of lattice vibrations on the PDF peak widths.Comment: 9 pages, 11 figure

Anomalous relaxation and self-organization in non-equilibrium processes

We study thermal relaxation in ordered arrays of coupled nonlinear elements with external driving. We find, that our model exhibits dynamic self-organization manifested in a universal stretched-exponential form of relaxation. We identify two types of self-organization, cooperative and anti-cooperative, which lead to fast and slow relaxation, respectively. We give a qualitative explanation for the behavior of the stretched exponent in different parameter ranges. We emphasize that this is a system exhibiting stretched-exponential relaxation without explicit disorder or frustration.Comment: submitted to PR

Spectral Evidence for Emergent Order in Ba1−x_{1-x}Nax_xFe2_2As2_2

We report an angle-resolved photoemission spectroscopy study of the iron-based superconductor family, Ba$_{1-x}$Na$_x$Fe$_2$As$_2$. This system harbors the recently discovered double-Q magnetic order appearing in a reentrant C$_4$ phase deep within the underdoped regime of the phase diagram that is otherwise dominated by the coupled nematic phase and collinear antiferromagnetic order. From a detailed temperature-dependence study, we identify the electronic response to the nematic phase in an orbital-dependent band shift that strictly follows the rotational symmetry of the lattice and disappears when the system restores C$_4$ symmetry in the low temperature phase. In addition, we report the observation of a distinct electronic reconstruction that cannot be explained by the known electronic orders in the system