WL 17: A Young Embedded Transition Disk

We present the highest spatial resolution ALMA observations to date of the Class I protostar WL 17 in the $\rho$ Ophiuchus L1688 molecular cloud complex, which show that it has a 12 AU hole in the center of its disk. We consider whether WL 17 is actually a Class II disk being extincted by foreground material, but find that such models do not provide a good fit to the broadband SED and also require such high extinction that it would presumably arise from dense material close to the source such as a remnant envelope. Self-consistent models of a disk embedded in a rotating collapsing envelope can nicely reproduce both the ALMA 3 mm observations and the broadband SED of WL 17. This suggests that WL 17 is a disk in the early stages of its formation, and yet even at this young age the inner disk has been depleted. Although there are multiple pathways for such a hole to be created in a disk, if this hole were produced by the formation of planets it could place constraints on the timescale for the growth of planetesimals in protoplanetary disks.Comment: 7 pages, 3 figures, 2 tables, accepted for publication in ApJ

Using a smartphone app to identify signs of pre-eclampsia and/or worsening blood pressure

Background Hypertensive disorders of pregnancy complicate 10% of pregnancies and can have serious consequences. Aims To explore the experiences of pregnant women with a history of hypertension using an innovative home blood pressure monitoring device. Methods A qualitative study using a grounded theory approach was undertaken. Data were collected through semi-structured interviews. Women were given a blood pressure machine to monitor their blood pressure daily. They inserted their blood pressure results on a smartphone app and answered questions for signs of pre-eclampsia. Participants were followed up every 2 weeks. Findings The results suggested that women wanted a holistic care pathway for the management of hypertension in pregnancy. Three subcategories (‘empowerment’, ‘comparison of care pathways’ and ‘continuity of care’) were also identified. Conclusions The traditional management of hypertension in pregnancy is not holistic. The home blood pressure service was accepted by women and incorporated elements of holistic care but more is required to meet the standard of care that women need

Assumptions of IV Methods for Observational Epidemiology

Instrumental variable (IV) methods are becoming increasingly popular as they seem to offer the only viable way to overcome the problem of unobserved confounding in observational studies. However, some attention has to be paid to the details, as not all such methods target the same causal parameters and some rely on more restrictive parametric assumptions than others. We therefore discuss and contrast the most common IV approaches with relevance to typical applications in observational epidemiology. Further, we illustrate and compare the asymptotic bias of these IV estimators when underlying assumptions are violated in a numerical study. One of our conclusions is that all IV methods encounter problems in the presence of effect modification by unobserved confounders. Since this can never be ruled out for sure, we recommend that practical applications of IV estimators be accompanied routinely by a sensitivity analysis.Comment: Published in at http://dx.doi.org/10.1214/09-STS316 the Statistical Science (http://www.imstat.org/sts/) by the Institute of Mathematical Statistics (http://www.imstat.org

Grand narratives then and now: can we still conceptualise history?

Reading the Communist Manifesto today, it is impossible not to be struck by the confidence with which it conceptualises history. The positive energy of this bold grand narrative stands in such stark contrast to the negative and jaded mentality of our times, which conceives of grand narratives only to tell us that there can be none. Such talk as there is of history today is more likely to be of "the end of history". There are three senses in which references to the end of history feature in contemporary debates: apocalyptic prediction, postmodernist pronouncement and capitalist triumphalism. This paper addresses the crisis of historicity in our time in relation to these positions and asks what is it about our age that produces them. It explores the widespread rejection of grand narratives, as well as grand narratives, which nevertheless persist, implicit and explicit, right and left. It looks at the position of marxism in the 1990s, counterposing it to postmarxism and postmodernism in particular on the question of grand narratives. It calls for resistance to the detotalising pressures of the age and revival of a totalising (as opposed to totalised) philosophy of history

Complex decisions : deconstructing best a grounded theory study of infant feeding decisions in the first six weeks post-birth

University of Technology, Sydney. Faculty of Nursing Midwifery and Health.Breastfeeding is promoted globally as the optimum method of infant feeding. Despite this, breastfeeding initiation and duration rates differ significantly between and within countries, as well as social and cultural groups. While Australian breastfeeding initiation rates appear high, breastfeeding rates decline quite significantly in the first six weeks. In an effort to implement strategies to increase breastfeeding rates, many research efforts have aimed at identifying factors that predict breastfeeding initiation and duration and/or breastfeeding attrition. These studies have predominantly used quantitative methodologies, and although a number of factors associated with the infant feeding decision have been identified, the mechanisms by which they affect the decision remain unknown. In contrast to quantitative studies, a much smaller amount of qualitative research has explored aspects of the infant feeding experience and has found the experience of breastfeeding to be complex. Rather than simply being an individual act, infant feeding decisions are constructed and practiced within the social milieu in which women live. The purpose of this research was to explore and describe the experiences of women making infant feeding decisions in the first six weeks post-birth. A constructionist grounded theory methodology was used to collect and analyse data. Data were collected through in-depth interviews with thirty-seven women. The women were theoretically sampled in accordance with the principles of grounded theory. In addition to the empirical study, literature focusing on breastfeeding, aspects of the postnatal period and mothering, was used to inform, strengthen and help explain the findings emerging from the empirical data. Four main categories emerged from the data that described what women deemed important to their infant feeding decisions. These categories were 'it's really best to breastfeed', 'it's the unknown', 'its not the only thing going on', and 'everybody's best is different'. The Basic Social Process, which was also the core category, was labelled 'deconstructing best'. The core category 'deconstructing best' linked the categories in a process of decision-making that the women embarked on during this period. It demonstrates the individuality of the experience and provides an explanation as to why trajectories of experience cannot be explicated and predicting outcomes has been unsuccessful. The findings demonstrate that women's infant feeding decisions in the first six weeks post-birth are multifactorial. In contrast to this, hospital policies as well as health professionals' understandings and practices, are generally embedded in the concept that breast is best

Decoding coalescent hidden Markov models in linear time

In many areas of computational biology, hidden Markov models (HMMs) have been used to model local genomic features. In particular, coalescent HMMs have been used to infer ancient population sizes, migration rates, divergence times, and other parameters such as mutation and recombination rates. As more loci, sequences, and hidden states are added to the model, however, the runtime of coalescent HMMs can quickly become prohibitive. Here we present a new algorithm for reducing the runtime of coalescent HMMs from quadratic in the number of hidden time states to linear, without making any additional approximations. Our algorithm can be incorporated into various coalescent HMMs, including the popular method PSMC for inferring variable effective population sizes. Here we implement this algorithm to speed up our demographic inference method diCal, which is equivalent to PSMC when applied to a sample of two haplotypes. We demonstrate that the linear-time method can reconstruct a population size change history more accurately than the quadratic-time method, given similar computation resources. We also apply the method to data from the 1000 Genomes project, inferring a high-resolution history of size changes in the European population.Comment: 18 pages, 5 figures. To appear in the Proceedings of the 18th Annual International Conference on Research in Computational Molecular Biology (RECOMB 2014). The final publication is available at link.springer.co

Agriculture's Role in Greenhouse Gas Mitigation

Examines technical, economic, and policy trends. Explores efforts to encourage farmers to adopt new agricultural practices that reduce agricultural greenhouse gas emissions. Reviews biofuel options, and related policy implications

Enumeration in Alzheimer's disease and other late life psychiatric syndromes

Previous studies suggest that visual enumeration is spared in normal aging but impaired in abnormal aging (late stage Alzheimer's disease, AD), raising the task's potential as a marker of dementia. Experiment 1 compared speeded enumeration of 1–9 random dots in early stage AD, vascular dementia (VAD), depression, and age-matched controls. Previous deficits were replicated but they were not specific to AD, with the rate of counting larger numerosities similarly slowed relative to controls by both AD and VAD. Determination of subitizing span was complicated by the surprisingly slower enumeration of one than of two items, especially in AD patients. Experiment 2 showed that AD patients’ relative difficulty with one item persisted with further practice and extended to the enumeration of targets among distractors. However, it was abolished when pattern recognition was possible (enumerating dots on a die). Although an enumeration test is unlikely to help differentiate early AD from other common dementias, the unexpected pattern of patients’ performance challenges current models of enumeration and requires further investigation