Nonlinear wave propagation and reconnection at magnetic X-points in the Hall MHD regime

The highly dynamical, complex nature of the solar atmosphere naturally implies the presence of waves in a topologically varied magnetic environment. Here, the interaction of waves with topological features such as null points is inevitable and potentially important for energetics. The low resistivity of the solar coronal plasma implies that non-MHD effects should be considered in studies of magnetic energy release in this environment. This paper investigates the role of the Hall term in the propagation and dissipation of waves, their interaction with 2D magnetic X-points and the nature of the resulting reconnection. A Lagrangian remap shock-capturing code (Lare2d) is used to study the evolution of an initial fast magnetoacoustic wave annulus for a range of values of the ion skin depth in resistive Hall MHD. A magnetic null-point finding algorithm is also used to locate and track the evolution of the multiple null-points that are formed in the system. Depending on the ratio of ion skin depth to system size, our model demonstrates that Hall effects can play a key role in the wave-null interaction. In particular, the initial fast-wave pulse now consists of whistler and ion-cyclotron components; the dispersive nature of the whistler wave leads to (i) earlier interaction with the null, (ii) the creation of multiple additional, transient nulls and, hence, an increased number of energy release sites. In the Hall regime, the relevant timescales (such as the onset of reconnection and the period of the oscillatory relaxation) of the system are reduced significantly, and the reconnection rate is enhanced.Comment: 13 pages, 10 figure

Unstable coronal loops : numerical simulations with predicted observational signatures

We present numerical studies of the nonlinear, resistive magnetohydrodynamic (MHD) evolution of coronal loops. For these simulations we assume that the loops carry no net current, as might be expected if the loop had evolved due to vortex flows. Furthermore the initial equilibrium is taken to be a cylindrical flux tube with line-tied ends. For a given amount of twist in the magnetic field it is well known that once such a loop exceeds a critical length it becomes unstableto ideal MHD instabilities. The early evolution of these instabilities generates large current concentrations. Firstly we show that these current concentrations are consistent with the formation of a current sheet. Magnetic reconnection can only occur in the vicinity of these current concentrations and we therefore couple the resistivity to the local current density. This has the advantage of avoiding resistive diffusion in regions where it should be negligible. We demonstrate the importance of this procedure by comparison with simulations based on a uniform resistivity. From our numerical experiments we are able to estimate some observational signatures for unstable coronal loops. These signatures include: the timescale of the loop brightening; the temperature increase; the energy released and the predicted observable flow speeds. Finally we discuss to what extent these observational signatures are consistent with the properties of transient brightening loops.Comment: 13 pages, 9 figure

Optimization of plasma mirror reflectivity and optical quality using double laser pulses

We measure a record 962.5 % specularly reflected energy fraction from an interaction with a plasma mirror surface preionised by a controlled prepulse and find that the optical quality is dependent on the inter pulse time delay. Simulations show that the main pulse reflected energy is a strong function of plasma density scale length, which increases with the time delay and reaches a peak reflectivity for a scale length of 0.3 m, which is achieved here for a pulse separation time of 3 ps. It is found that the incident laser quasi near field intensity distribution leads to nonuniformities in this plasma expansion and consequent critical surface position distribution. The plasma mirror optical quality is found to be governed by the resultant perturbations in the critical surface position, which become larger with inter pulse time delay

Social inequalities in self-rated health by age: Cross-sectional study of 22 457 middle-aged men and women

<p>Abstract</p> <p>Background</p> <p>We investigate the association between occupational social class and self-rated health (SRH) at different ages in men and women.</p> <p>Methods</p> <p>Cross sectional population study of 22 457 men and women aged 39–79 years living in the general community in Norfolk, United Kingdom, recruited using general practice age-sex registers in 1993–1997. The relationship between self-rated health and social class was examined using logistic regression, with a poor or moderate rating as the outcome.</p> <p>Results</p> <p>The prevalence of poor or moderate (lower) self-rated health increased with increasing age in both men and women. There was a strong social class gradient: in manual classes, men and women under 50 years of age had a prevalence of lower self-rated health similar to that seen in men and women in non-manual social classes over 70 years old. Even after adjustment for age, educational status, and lifestyle factors (body mass index (BMI), smoking, physical activity and alcohol consumption) there was still strong evidence of a social gradient in self-rated health, with unskilled men and women approximately twice as likely to report lower self-rated health as professionals (OR_men= 2.44 (95%CI 1.69, 3.50); OR_women= 1.97 (95%CI 1.45, 2.68).</p> <p>Conclusion</p> <p>There was a strong gradient of decreased SRH with age in both men and women. We found a strong cross-sectional association between SRH and social class, which was independent of education and major health related behaviors. The social class differential in SRH was similar with age. Prospective studies to confirm this association should explore social and emotional as well as physical pathways to inequalities in self reported health.</p

The Effects of Defamilisation and Familisation Measures on the Accumulation of Retirement Income for Women in the UK

This paper is concerned with the link between the effects of pro-market pension reforms on women and familisation/defamilisation measures. It aims to contribute to the study of this link in three ways. Firstly, it identifies defamilisation/familisation measures which have the potential to reduce negative effects of pro-market pension measures on women. Secondly, based on the examples from the UK, it shows that the government’s willingness to provide sufficient defamilisation/familisation measures to assist women to deal with the negative effects of the pro-market pension measures should not be taken for granted. Thirdly, it suggests ways for tackling this problem

Exploring the Support Needs of Family Caregivers of Patients with Brain Cancer Using the CSNAT: A Comparative Study with Other Cancer Groups

A substantial burden is placed on family caregivers of patients diagnosed with brain cancers. Despite this, the support needs of the caregivers are often under-recognised and not addressed adequately in current routine and patient centred clinical care. The Care Support Needs Assessment Tool (CSNAT) is a validated instrument designed to systematically identify and address caregiver needs. It has been trialled in an Australian palliative care community setting using a stepped wedge cluster design involving 322 family carers of terminally ill patients. The current article reports on a subset from this trial, 29 caregivers of patients with primary brain cancer, and compares their profile and outcomes to those of other cancer groups. Caregiver strain was assessed using the Family Appraisal of Caregiving Questionnaire, caregiver physical and mental wellbeing using SF12 and caregiver workload using a questionnaire on support with activities of daily living (ADL). In comparison to caregivers of patients with all other cancers, the primary brain cancer group had significantly higher levels of caregiver strain, lower levels of mental wellbeing and a higher level of ADL workload. Their physical wellness also deteriorated significantly over time.An action plan approach led to practical solutions for addressing highlighted concerns. Four themes evolved from the family caregivers’ feedback interviews: The extremely challenging caregiver experience with brain cancer; the systematic and practical approach of the CSNAT during rapid changes; connection with health professionals, feeling acknowledged and empowered; and timely advice and assurance of support during the caregiving journey. This preliminary study has demonstrated that the CSNAT provides a practical and useful tool for assessing the support needs of family caregivers of patients with brain cancer and has provided the basis for a larger scale, longitudinal study that allows a more detailed characterisation of the evolving caregiver needs at different stages of the disease

Quercetin elevates p27Kip1 and arrests both primary and HPV16 E6/E7 transformed human keratinocytes in G1

Our previous work with primary bovine fibroblasts demonstrated that quercetin, a potent mutagen found in high levels in bracken fern (Pteridium aquilinum), arrested cells in G1 and G2/M, in correlation with p53 activation. The expression of bovine papillomavirus type 4 (BPV-4) E7 overcame this arrest and lead to the development of tumorigenic cells lines (Beniston et al., 2001). Given the possible link between papillomavirus infection, bracken fern in the diet and cancer of the upper gastrointestinal (GI) tract in humans, we investigated whether a similar situation would occur in human cells transformed by human papillomavirus type 16 (HPV-16) oncoproteins. Quercetin arrested primary human foreskin keratinocytes in G1. Arrest was linked to an elevation of the cyclin-dependent kinase inhibitor (cdki) p27Kip1. Expression of the HPV16 E6 and E7 oncoproteins in transformed cells failed to abrogate cell cycle arrest. G1 arrest in the transformed cells was also linked to an increase of p27Kip1 with a concomitant reduction of cyclin E-associated kinase activity. This elevation of p27Kip1 was due not only to increased protein half-life, but also to increased mRNA transcription

Classical Morphology of Plants as an Elementary Instance of Classical Invariant Theory

It has long been known that structural chemistry shows an intriguing correspondence with Classical Invariant Theory (CIT). Under this view, an algebraic binary form of the degree n corresponds to a chemical atom with valence n and each physical molecule or ion has an invariant-theoretic counterpart. This theory was developed using the Aronhold symbolical approach and the symbolical processes of convolution/transvection in CIT was characterized as a potential “accurate morphological method”. However, CIT has not been applied to the formal morphology of living organisms. Based on the morphological interpretation of binary form, as well as the process of convolution/transvection, the First and Second Fundamental Theorems of CIT and the Nullforms of CIT, we show how CIT can be applied to the structure of plants, especially when conceptualized as a series of plant metamers (phytomers). We also show that the weight of the covariant/invariant that describes a morphological structure is a criterion of simplicity and, therefore, we argue that this allows us to formulate a parsimonious method of formal morphology. We demonstrate that the “theory of axilar bud” is the simplest treatment of the grass seedling/embryo. Our interpretations also represent Troll's bauplan of the angiosperms, the principle of variable proportions, morphological misfits, the basic types of stem segmentation, and Goethe's principle of metamorphosis in terms of CIT. Binary forms of different degrees might describe any repeated module of plant organisms. As bacteria, invertebrates, and higher vertebrates are all generally shared a metameric morphology, wider implications of the proposed symmetry between CIT and formal morphology of plants are apparent

Efficient ion acceleration and dense electron-positron plasma creation in ultra-high intensity laser-solid interactions

The radiation pressure of next generation ultra-high intensity ($>10^{23}$ W/cm$^{2}$) lasers could efficiently accelerate ions to GeV energies. However, nonlinear quantum-electrodynamic effects play an important role in the interaction of these laser pulses with matter. Here we show that these effects may lead to the production of an extremely dense ($\sim10^{24}$ cm$^{-3}$) pair-plasma which absorbs the laser pulse consequently reducing the accelerated ion energy and energy conversion efficiency by up to 30-50\%

Monocot plastid phylogenomics, timeline, net rates of species diversification, the power of multiâ gene analyses, and a functional model for the origin of monocots

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146610/1/ajb21178-sup-0009-AppendixS9.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146610/2/ajb21178-sup-0020-AppendixS20.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146610/3/ajb21178.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146610/4/ajb21178-sup-0019-AppendixS19.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146610/5/ajb21178-sup-0010-AppendixS10.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146610/6/ajb21178-sup-0002-AppendixS2.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146610/7/ajb21178-sup-0006-AppendixS6.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146610/8/ajb21178-sup-0012-AppendixS12.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146610/9/ajb21178-sup-0017-AppendixS17.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146610/10/ajb21178-sup-0007-AppendixS7.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146610/11/ajb21178-sup-0001-AppendixS1.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146610/12/ajb21178-sup-0003-AppendixS3.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146610/13/ajb21178-sup-0016-AppendixS16.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146610/14/ajb21178_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146610/15/ajb21178-sup-0008-AppendixS8.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146610/16/ajb21178-sup-0004-AppendixS4.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146610/17/ajb21178-sup-0018-AppendixS18.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146610/18/ajb21178-sup-0014-AppendixS14.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146610/19/ajb21178-sup-0011-AppendixS11.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146610/20/ajb21178-sup-0005-AppendixS5.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146610/21/ajb21178-sup-0015-AppendixS15.pd