Nielsen-Olesen strings in Supersymmetric models

We investigate the behaviour of a model with two oppositely charged scalar fields. In the Bogomol'nyi limit this may be seen as the scalar sector of N=1 supersymmetric QED, and it has been shown that cosmic strings form. We examine numerically the model out of the Bogomol'nyi limit, and show that this remains the case. We then add supersymmetry-breaking mass terms to the supersymmetric model, and show that strings still survive. Finally we consider the extension to N=2 supersymmetry with supersymmetry-breaking mass terms, and show that this leads to the formation of stable cosmic strings, unlike in the unbroken case.Comment: 7 pages, 2 figues, uses revtex4; minor typos corrected; references adde

Thermal Softening and Degradation of Wood and Bark

A thermogravimetric analyzer was modified for the study of thermal softening of several Pacific Northwest woods and barks under constant load at a heating rate of 16 C/min.Several stages of thermal softening were found in barks and wood. Regardless of species, oven-dry samples start to soften at 180 C, with termination at about 500 C. The maximum rate of softening occurred at 380 C with an additional softening at 280 C for bark and 320 C for wood of hardwood species. An increase of moisture content decreased the softening temperature. When the moisture content of either material was higher than 10%, a new maximum rate of softening appeared at 160 C, while the 280 C, 320 C and 380 C maxima were retained. The absolute softening of wood and bark at 160 C increased with increasing moisture content to a limit at about 30%.In conjunction with results from infrared spectrum, X-ray diffraction and differential thermal analysis, the heating of oven-dry wood and bark was found to exhibit neither physical nor chemical changes at less than 200 C. The softening of wood and bark in the presence of water at temperature less than 200 C must occur only in the amorphous regions, with water serving as a plasticizer. Softening of wood and bark at more than 200 C is a combined response of physical and chemical degradations. These thermal responses of wood and bark, particularly bark, are expected to be important to the strength, dimensional stability, water resistance and fire-retardant properties of composite products

Critical phenomena in a highly constrained classical spin system: Neel ordering from the Coulomb phase

Many classical, geometrically frustrated antiferromagnets have macroscopically degenerate ground states. In a class of three-dimensional systems, the set of degenerate ground states has power-law correlations and is an example of a Coulomb phase. We investigate Neel ordering from such a Coulomb phase, induced by weak additional interactions that lift the degeneracy. We show that the critical point belongs to a universality class that is different from the one for the equivalent transition out of the paramagnetic phase, and that it is characterised by effective long-range interactions; alternatively, ordering may be discontinuous. We suggest that a transition of this type may be realised by applying uniaxial stress to a pyrochlore antiferromagnet.Comment: 4 pages, 3 figure

A Bayesian approach to estimate changes in condom use from limited human immunodeficiency virus prevalence data.

Evaluation of large-scale intervention programmes against human immunodeficiency virus (HIV) is becoming increasingly important, but impact estimates frequently hinge on knowledge of changes in behaviour such as the frequency of condom use over time, or other self-reported behaviour changes, for which we generally have limited or potentially biased data. We employ a Bayesian inference methodology that incorporates an HIV transmission dynamics model to estimate condom use time trends from HIV prevalence data. Estimation is implemented via particle Markov chain Monte Carlo methods, applied for the first time in this context. The preliminary choice of the formulation for the time varying parameter reflecting the proportion of condom use is critical in the context studied, because of the very limited amount of condom use and HIV data available. We consider various novel formulations to explore the trajectory of condom use over time, based on diffusion-driven trajectories and smooth sigmoid curves. Numerical simulations indicate that informative results can be obtained regarding the amplitude of the increase in condom use during an intervention, with good levels of sensitivity and specificity performance in effectively detecting changes. The application of this method to a real life problem demonstrates how it can help in evaluating HIV interventions based on a small number of prevalence estimates, and it opens the way to similar applications in different contexts

Associations between maternal prenatal cortisol and fetal growth are specific to infant sex: findings from the Wirral Child Health and Development Study

Recent findings highlight that there are prenatal risks for affective disorders that are mediated by glucocorticoid mechanisms, and may be specific to females. There is also evidence of sex differences in prenatal programming mechanisms and developmental psychopathology, whereby effects are in opposite directions in males and females. As birth weight is a risk for affective disorders, we sought to investigate whether maternal prenatal cortisol may have sex-specific effects on fetal growth. Participants were 241 mothers selected from the Wirral Child Health and Development Study (WCHADS) cohort (n=1233) using a psychosocial risk stratifier, so that responses could be weighted back to the general population. Mothers provided saliva samples, which were assayed for cortisol, at home over 2 days at 32 weeks gestation (on waking, 30-min post-waking and during the evening). Measures of infant birth weight (corrected for gestational age) were taken from hospital records. General population estimates of associations between variables were obtained using inverse probability weights. Maternal log of the area under the curve cortisol predicted infant birth weight in a sex-dependent manner (interaction term P=0.029). There was a positive and statistically significant association between prenatal cortisol in males, and a negative association in females that was not statistically significant. A sex interaction in the same direction was evident when using the waking (P=0.015), and 30-min post-waking (P=0.013) cortisol, but not the evening measure. There was no interaction between prenatal cortisol and sex to predict gestational age. Our findings add to an emerging literature that suggests that there may be sex-specific mechanisms that underpin fetal programming

Transduction of Non-Small Cell Lung Cancer Cells by Adenoviral and Retroviral Vectors

Gene transfer into a panel of non-small cell lung cancer (NSCLC) cells by adenoviral (Ad) and retroviral (RV) vectors was studied. Indexed to multiplicity of infection (MOI), Ad vectors transduce squamous, adenosquamous, and malignant mesothelioma cells with greater efficiency than large cells or adenocarcinoma cells. Transduction-sensitive cells bind the Ad vector with specificity for the Ad fiber knob, and internalize vector efficiently. Transduction-refractory cells bind and internalize vector by less efficient pathways. Like Ad vectors, there is heterogeneity in RV transduction efficiencies of different NSCLC subtypes. With respect to the most common cell type metastatic to the pleural space (adenocarcinoma), amphotropic retroviral vectors transduce cells of this subtype more efficiently (at a lower MOI) than Ad. RV transduction is not solely dependent on cellular replication, and both permissive and refractory cell lines express the mRNA for the amphotropic RV receptor. These observations suggest that neither Ad nor RV vectors will suffice a priori as the optimal gene transfer vehicle, and successful gene therapy of lung cancer may require tumor-specific or patient-specific vectors

Evidence for interplay between genes and parenting on infant temperament in the first year of life: monoamine oxidase A polymorphism moderates effects of maternal sensitivity on infant anger proneness

Background The low expression polymorphism of the MAOA gene in interaction with adverse environments (G × E) is associated with antisocial behaviour disorders. These have their origins in early life, but it is not known whether MAOA G × E occurs in infants. We therefore examined whether MAOA G × E predicts infant anger proneness, a temperamental dimension associated with later antisocial behaviour disorders. In contrast to previous studies, we examined MAOA G × E prospectively using an observational measure of a key aspect of the infant environment, maternal sensitivity, at a specified developmental time point. Methods In a stratified epidemiological cohort recruited during pregnancy, we ascertained MAOA status (low vs. high expression alleles) from the saliva of 193 infants, and examined specific predictions to maternal report of infant temperament at 14 months from maternal sensitivity assessed at 29 weeks of age. Results Analyses, weighted to provide general population estimates, indicated a robust interaction between MAOA status and maternal sensitivity in the prediction of infant anger proneness (p = .003) which became stronger once possible confounders for maternal sensitivity were included in the model (p = .0001). The interaction terms were similar in males (p = .010) and females (p = .016), but the effects were different as a consequence of an additional sex of infant by maternal sensitivity interaction. Conclusions This prospective study provides the first evidence of moderation by the MAOA gene of effects of parenting on infant anger proneness, an important early risk for the development of disruptive and aggressive behaviour disorders

Screening for cervical, prostate and breast cancer: interpreting the evidence

Cancer screening is well-established in high income countries, but its evidence base is constantly evolving and often contentious. This leaves physicians and policymakers in a difficult position, forced to act in the context of methodological complexity and substantive disagreement.1,2 Three cases of screening for cancer or cancer risk are considered: cervical, prostate and breast screening. The unique characteristics of the disease, test and program in each case are outlined in Table 1. Tables 2-4, catalogue sources of controversy in each case; these are discussed in more depth below. The concluding section presents five common themes that may help explain the ongoing controversies. The aim is not to synthesize the evidence, but to provide the ‘backroom’ story of the evidence on cancer screening, and so illuminate why experts so often disagree.This work is supported by the Australian National Health and Medical Research Council (NHMRC), under Project Grant 1023197. SC is supported by NHMRC Career Development Fellowship 1032963. LP is supported by NHMRC Postgraduate Scholarship 1038517. JG is supported by NHMRC Postgraduate Scholarship 1074626. JW is supported by an Australian Postgraduate Award