Barriers to cervical screening participation in high-risk women

Aim Women aged 25–35 years, for whom cervical cancer is most problematic, are least likely to participate in the cervical screening programme. Therefore, identifying barriers to screening participation in this high-risk group is essential. Subject and methods A sample of 430 women completed an electronic survey of their cervical screening history and answered questions on sociodemographic, behavioural, attitudinal and informational barriers to cervical screening uptake. Logistic regression was used to predict cervical screening non attendance. Results Women with more than 10 sexual partners in their lifetime were more likely, but women from ethnic minorities, less likely to participate in the cervical screening programme. Women unaware of the recommended screening interval were also less likely to be screened, as were women who believed that screening is a test for cancer. Screening was also less likely among women who endorsed the belief that screening in the absence of symptoms is unnecessary. Conclusion These data highlight poor knowledge of the recommended screening interval and purpose of cervical cancer screening in this high-risk group. As such, interventions that target these informational barriers might be most effective for increasing cervical screening uptake in this high-risk group

Anticipating the XRISM search for the decay of resonantly produced sterile neutrino dark matter

The resonantly produced sterile neutrino ($N_1$) of the neutrino minimal standard model ($\nu$MSM) is a compelling dark matter candidate, especially in the reported possible detection of $N_1$ with mass $m_\mathrm{s}=7.1$~keV in X-ray decay. This particle will be accessible to the XRISM X-ray mission over the next 12 months. We revisit the physics behind $N_1$ and the uncertainty in its parameters. We compare predictions for the $m_\mathrm{s}=7.1$keV $N_1$ mixing angle, $\sin^{2}(2\theta)$, and half-mode mass, $M_\mathrm{hm}$, to existing X-ray observations and structure formation constraints. The strongest available constraints rule out $N_1$ as a dark matter candidate, and a more optimistic reading of the data prefers $\sin^{2}(2\theta)=5\times10^{-11}$ and $M_\mathrm{hm}=3.5\times10^{8}$$\mathrm{M}_{\odot}$. We highlight that the most promising upcoming opportunity for a detection is to find a line of velocity dispersion $\sim500$$\mathrm{kms^{-1}}$ in the Virgo cluster with XRISM, and then draw up a list of future objects of study to determine: (i) whether the line is from dark matter generally, and (ii) if from dark matter, whether that candidate is indeed $N_1$.Comment: 13 pages, 7 figures. To be submitted to MNRAS. Contact: [email protected]

Halo assembly in cold and warm dark matter during the JWST frontier epoch

The JWST mission is in the process of probing the galaxy mass function at $z>10$, when conceivably any delay in halo assembly due to the presence of a dwarf galaxy-scale power spectrum cutoff may drastically suppress the number of galaxies relative to the cold dark matter (CDM) expectation. We employ N-body simulations of CDM and warm dark matter (WDM) to explore how the difference in halo collapse time between these models scales with $z=0$ descendant halo mass. We demonstrate that collapse begins first for the most massive haloes, and the delay in collapse time between CDM and WDM haloes correlates inversely with descendant mass. We thus infer that only present-day dwarf galaxies exhibit any difference in their assembly history between CDM and WDM at $z=10$, and therefore support previous studies that have found JWST is unlikely to determine whether our Universe is better described by the CDM cosmology or the WDM cosmology without favourable lensing studies.Comment: 9 pages, 6 figures, to be submitted to MNRAS. Contact: [email protected]

Halo Substructure and the Nature of Dark Matter

The ΛCDM paradigm has been very successful at predicting the properties of the large scale (> 10Mpc) Universe, but has recently struggled to explain phenomena observed on small scales, such as the central densities, abundances, and orbital configurations of satellite galaxies. This emergence of tension between observations and theory has co- incided with CERN measurements that disfavour the simplest supersymmetric models, which provide some of the most popular cold dark matter candidate particles. One pos- sible solution to some of these problems is that the dark matter may instead be made up of sterile neutrinos: these particles would have masses of 1-10keV and behave as ’warm’ dark matter (WDM), with consequences for the formation of galaxies. In this thesis we use high resolution simulations of Milky Way-analogue dark matter haloes to examine the role of filaments on satellite orbits and WDM on satellite abundance and structure. We find in the former case that dark matter filaments can funnel subhaloes into cor- related orbits and so ease the tension with observations. We also find that WDM is a possible solution to the problem of satellite galaxy densities, since structure formation is delayed in WDM and thus the centres of haloes form when the density of the Universe is lower. In order to generate the required number of satellite galaxies, we find that the WDM thermal-equivalent particle mass > 1.6keV. In addition to the work on satellite galaxies, we use a series of gas-hydrodynamic simulations of our Milky Way-analogue halo to examine the process of reionisation in WDM. We find that the suppression of small scale structure in the 1.4keV WDM model prevents the simulated L∗ galaxy, along with its satellites, from reionising its own local volume quickly enough to satisfy the reionisation redshift constraint set by the recent Planck satellite results, in contrast to CDM

The psychophysiological and health corollaries of child problem behaviours in caregivers of children with autism and ADHD

Background The positive relationship between problem behaviours of children with additional complex needs and psychological distress in their caregivers has been widely evidenced. Fewer studies, however, have assessed the relationship between care recipients’ problem behaviours and key physiological processes, relevant for the physical health status of their care providers. This study examined the psychological, endocrine and health corollaries of child problem behaviours in caregivers of children with autism and attention deficit hyperactivity disorder. Methods Caregivers (n = 18) completed self-report measures of psychological distress, child problem behaviours and incidences of commonly occurring ailments. To capture important parameters of the basal diurnal cortisol pattern, caregivers collected saliva samples at waking, 30 min post waking, 1200 h and 2200 h on two consecutive weekdays. Results Data revealed a positive relationship between caregivers’ perceived levels of stress and problems with child conduct behaviours. In addition, caregivers who reported more problems with child emotional and hyperactivity behaviours displayed atypical cortisol patterns characterised by flatter diurnal cortisol slopes and reduced cortisol awakening response magnitude. Subjective reports of commonly occurring ailments were also greater in caregivers experiencing more problems with child emotional behaviours. Conclusions These findings have implications for interventions that aim to improve the psychophysiological well-being of the caregiver by targeting problem behaviours of the care recipient

Investigation of Strain Aging in the Ordered Intermetallic Compound beta-NiAl

The phenomenon of strain aging has been investigated in polycrystalline and single crystal NiAl alloys at temperatures between 300 and 1200 K. Static strain aging studies revealed that after annealing at 1100 K for 7200 s (i.e., 2h) followed by furnace cooling, high purity, nitrogen-doped and titanium-doped polycrystalline alloys exhibited continuous yielding, while conventional-purity and carbon-doped alloys exhibited distinct yield points and Luders strains. Prestraining by hydrostatic pressurization removed the yield points, but they could be reintroduced by further annealing treatments. Yield points could be reintroduced more rapidly if the specimens were prestrained uniaxially rather than hydrostatically, owing to the arrangement of dislocations into cell structures during uniaxial deformation. The time dependence of the strain aging events followed at t(exp 2/3) relationship suggesting that the yield points observed in polycrystalline NiAl were the result of the pinning of mobile dislocations by interstitials, specifically carbon. Between 700 and 800 K, yield stress plateaus, yield stress transients upon a ten-fold increase in strain rate, work hardening peaks, and dips in the strain rate sensitivity (SRS) have been observed in conventional-purity and carbon-doped polycrystals. In single crystals, similar behavior was observed; in conventional-purity single crystals, however, the strain rate sensitivity became negative resulting in serrated yielding, whereas, the strain rate sensitivity stayed positive in high purity and in molybdenum-doped NiAl. These observations are indicative of dynamic strain aging (DSA) and are discussed in terms of conventional strain aging theories. The impact of these phenomena on the composition-structure-property relations are discerned. Finally, a good correlation has been demonstrated between the properties of NiAl alloys and a recently developed model for strain aging in metals and alloys developed by Reed-Hill et al

Oxidative DNA Damage in Mild Cognitive Impairment and Late-Stage Alzheimer\u27s Disease

Increasing evidence supports a role for oxidative DNA damage in aging and several neurodegenerative diseases including Alzheimer\u27s disease (AD). Attack of DNA by reactive oxygen species (ROS), particularly hydroxyl radicals, can lead to strand breaks, DNA–DNA and DNA–protein cross-linking, and formation of at least 20 modified bases adducts. In addition, α,β-unsaturated aldehydic by-products of lipid peroxidation including 4-hydroxynonenal and acrolein can interact with DNA bases leading to the formation of bulky exocyclic adducts. Modification of DNA bases by direct interaction with ROS or aldehydes can lead to mutations and altered protein synthesis. Several studies of DNA base adducts in late-stage AD (LAD) brain show elevations of 8-hydroxyguanine (8-OHG), 8-hydroxyadenine (8-OHA), 5-hydroxycytosine (5-OHC), and 5-hydroxyuracil, a chemical degradation product of cytosine, in both nuclear and mitochondrial DNA (mtDNA) isolated from vulnerable regions of LAD brain compared to age-matched normal control subjects. Previous studies also show elevations of acrolein/guanine adducts in the hippocampus of LAD subjects compared to age-matched controls. In addition, studies of base excision repair show a decline in repair of 8-OHG in vulnerable regions of LAD brain. Our recent studies show elevated 8-OHG, 8-OHA, and 5,6-diamino-5-formamidopyrimidine in both nuclear and mtDNA isolated from vulnerable brain regions in amnestic mild cognitive impairment, the earliest clinical manifestation of AD, suggesting that oxidative DNA damage is an early event in AD and is not merely a secondary phenomenon

Oxidative DNA damage in mild cognitive impairment and late-stage Alzheimer's disease

Increasing evidence supports a role for oxidative DNA damage in aging and several neurodegenerative diseases including Alzheimer's disease (AD). Attack of DNA by reactive oxygen species (ROS), particularly hydroxyl radicals, can lead to strand breaks, DNA–DNA and DNA–protein cross-linking, and formation of at least 20 modified bases adducts. In addition, α,β-unsaturated aldehydic by-products of lipid peroxidation including 4-hydroxynonenal and acrolein can interact with DNA bases leading to the formation of bulky exocyclic adducts. Modification of DNA bases by direct interaction with ROS or aldehydes can lead to mutations and altered protein synthesis. Several studies of DNA base adducts in late-stage AD (LAD) brain show elevations of 8-hydroxyguanine (8-OHG), 8-hydroxyadenine (8-OHA), 5-hydroxycytosine (5-OHC), and 5-hydroxyuracil, a chemical degradation product of cytosine, in both nuclear and mitochondrial DNA (mtDNA) isolated from vulnerable regions of LAD brain compared to age-matched normal control subjects. Previous studies also show elevations of acrolein/guanine adducts in the hippocampus of LAD subjects compared to age-matched controls. In addition, studies of base excision repair show a decline in repair of 8-OHG in vulnerable regions of LAD brain. Our recent studies show elevated 8-OHG, 8-OHA, and 5,6-diamino-5-formamidopyrimidine in both nuclear and mtDNA isolated from vulnerable brain regions in amnestic mild cognitive impairment, the earliest clinical manifestation of AD, suggesting that oxidative DNA damage is an early event in AD and is not merely a secondary phenomenon