Measuring the growth rate of structure with Type IA Supernovae from LSST

We investigate measuring the peculiar motions of galaxies up to $z=0.5$ using Type Ia supernovae (SNe Ia) from LSST, and predict the subsequent constraints on the growth rate of structure. We consider two cases. Our first is based on measurements of the volumetric SNe Ia rate and assumes we can obtain spectroscopic redshifts and light curves for varying fractions of objects that are detected pre-peak luminosity by LSST (some of which may be obtained by LSST itself and others which would require additional follow-up). We find that these measurements could produce growth rate constraints at $z<0.5$ that significantly outperform those using Redshift Space Distortions (RSD) with DESI or 4MOST, even though there are $\sim4\times$ fewer objects. For our second case, we use semi-analytic simulations and a prescription for the SNe Ia rate as a function of stellar mass and star formation rate to predict the number of LSST SNe IA whose host redshifts may already have been obtained with the Taipan+WALLABY surveys, or with a future multi-object spectroscopic survey. We find $\sim 18,000$ and $\sim 160,000$ SN Ia with host redshifts for these cases respectively. Whilst this is only a fraction of the total LSST-detected SNe Ia, they could be used to significantly augment and improve the growth rate constraints compared to only RSD. Ultimately, we find that combining LSST SNe Ia with large numbers of galaxy redshifts will provide the most powerful probe of large scale gravity in the $z<0.5$ regime over the coming decades.Comment: 12 pages, 1 table, 5 figures. Accepted for publication in ApJ. The Fisher matrix forecast code used in this paper can be found at: https://github.com/CullanHowlett/PV_fisher. Updated to fix error in Eq. 1 (thanks to Eric Linder for pointing this out

An optimal battery interchange policy for an electric car powered by a mobile solar power station

The World Solar Challenge is a 3000 kilometre race from Darwin to Adelaide, across the Australian continent, for solar powered racing cars. Annesley College accompanied the 2001 event in an electric car powered by batteries. While one battery was used to power the car another was charged from a solar panel carried by a mobile solar power station. When the first battery became empty the batteries were interchanged and the first battery put on charge. The process was repeated throughout the event. In this paper we find a policy for interchanging the batteries that maximises the distance travelled each day

A Chemical Reaction Network Drives Complex Population Dynamics in Oscillating Self-Reproducing Vesicles

We report chemically fueled oscillations of vesicles. The population cycling of vesicles is driven by their self-reproduction and collapse within a biphasic reaction network involving the interplay of molecular and supramolecular events. We studied the oscillations on the molecular and supramolecular scales and tracked vesicle populations in time by interferometric scattering microscopy and dynamic light scattering. Complex supramolecular events were observed during oscillationsincluding vesicle reproduction, growth, and decompositionand differences in the number, size, and mass of aggregates can often be observed within and between pulses. This system’s dynamic behavior is reminiscent of a reproductive cycle in living cells

Neurological disorders in Northern Tanzania: A 6-year prospective hospital-based case series

Background: The burden of neurological disorders is large and altered by the HIV epidemic. Objectives: We describe the pattern of neurological disorders and their association with HIV infection in adult patients attending a consultant hospital in Northern Tanzania. Methods: In this prospective cross-sectional study, we collected data on adult neurological referrals over a 6-year period between 2007-13. The odds of HIV infection, across neurological categories adjusted for age and sex, was calculated. Results: Of 2037 participants, 54.8% were male and 45.2% were female. The median age of participants was 43 years. The results for HIV screening were available for 992/2037 (48.7%) patients, of whom 306 (30.8%) were seropositive. The most frequent neurological disorders were cerebrovascular disease (19.9%), paraplegia (13.6%), and peripheral neuropathies (8%). Taken together CNS infection accounted for 278/2037 (13.6%). The adjusted odds (aOR) of HIV infection was highest amongst infections; brain abscesses (aOR 107, 95% CI 35.1-470.4) and meningitis/encephalitis (aOR 40.1, 95% CI 13.6-172.9), but also raised in cerebrovascular disease, paraplegia, peripheral neuropathies, cranial nerve palsies, seizures, cerebllar disorders, movement disorders, motor neuron disease and headache. Conclusion: The main pattern of neurological disorders in Northern Tanzania is presented. The odds of HIV infection was highest in CNS infections and in a wide range of non-communicable neurological disorders.publishedVersio

Simulation of monthly rainfall totals

The observed distribution of non-zero rainfall totals for a given month is often modelled using a maximum likelihood estimate for the Gamma distribution. In this paper we show that a Gamma distribution can be regarded as a zero order approximation to a density distribution constructed by a series of associated Laguerre polynomials. The coefficients of the series are easily calculated and used to improve the shape of the initial approximation by adjusting higher order moments. We show that this more general method models joint probability distributions for two or more months and in particular that the series model does not require an assumption of independence between months. Finally we explore how the series method generates simulated data that is statistically indistinguishable from the observed data. We illustrate our methods on a case study at Mawson Lakes and although monthly correlations may not be significant we note that the rainfall records at Koonamore Station show many significant correlations for successive months

Generating synthetic rainfall on various timescales daily, monthly and yearly

EXTENDED ABSTRACT The main objective of this paper is to present a model for generating synthetic rainfall totals on various timescales to be applicable for a variety of uses. Many large-scale ecological and water resources models require daily, monthly and yearly rainfall data as input to the model. As historical data provides only one realisation, synthetic generated rainfall totals are needed to assess the impact of rainfall variability on water resources systems A model for generating yearly totals will be described using traditional time series methods. This model, along with a similarly constructed daily generation model by, We present a new model for the generation of synthetic monthly rainfall data which we demonstrate for Parafield in Adelaide, South Australia. The rainfall for each month of the year is modelled as a non-negative random variable from a mixed distribution with either a zero outcome or a strictly positive outcome. We use maximum likelihood to find parameters for both the probability of a zero outcome and the gamma distribution that best matches the observed probability density for the strictly positive outcomes. We describe a new model that generates correlated monthly rainfall totals using a diagonal band copula with a single parameter to generate lag-1 correlated random numbers. Our model preserves the marginal monthly distributions and hence also preserves the monthly and yearly means. We show that for the particular example of Parafield the correlation between rainfall totals for successive months is not significant and so it is reasonable to assume independence. This is however not true for daily rainfall. The correlation between rainfall on successive days is certainly small but it is reasonable as suggested by The City of Salisbury supplies recycled stormwater to local businesses on a commercial basis and it is important that they understand the full implications of the likely distribution of rainfall and the consequent impact on their ability to manage the capture, treatment and supply to consumers of recycled water. Recent work b

Silicosis and silicotuberculosis among respiratory hospital admissions: A cross-sectional survey in northern Tanzania

Background. There is little evidence describing respiratory disease among 40.5 million small-scale miners worldwide. Objectives. To describe the prevalence and clinical characteristics of adult respiratory inpatients with silicosis and silicotuberculosis in a tertiary hospital in Tanzania that serves a small-scale mining region. Methods. In this retrospective, cross-sectional survey, patient files from admissions between 2010 and 2020 were opportunistically selected and included if a respiratory diagnosis had been made. Results. Of 223 patients with respiratory conditions, 32 (14.3%; 95% confidence interval (CI) 10.0 - 19.6) were diagnosed with silicosis and 17 (7.6%; 95% CI 4.5 - 11.9) with silicotuberculosis. Mining was the most frequent occupation in those with silicosis (n=15/32; 46.9%) and silicotuberculosis (n=15/17; 88.2%). Of those with silicosis or silicotuberculosis, 26/49 (53.1%) were aged <45 years. Conclusion. Our study suggests that silicosis and silicotuberculosis are common among male and female respiratory inpatients with occupational exposure. The study highlights the role of occupational exposures in respiratory disease in developing economies

The Short-Term Impact of Ontario's Generic Pricing Reforms

Background: Canadians pay amongst the highest generic drug prices in the world. In July 2010, the province of Ontario enacted a policy that halved reimbursement for generic drugs from the public drug plan, and substantially lowered prices for private purchases. We quantified the impact of this policy on overall generic drug expenditures in the province, and projected the impact in other provinces had they mimicked this pricing change. Methods: We used quarterly prescription generic drug dispensing data from the IMS-Brogan CompuScript Audit. We used the price per unit in both the pre- and post-policy period and two economics price indexes to estimate the expenditure reduction in Ontario. Further, we used the post-policy Ontario prices to estimate the potential reduction in other provinces. Results: We estimate that total expenditure on generic drugs in Ontario during the second half of 2010 was between $181 and$194 million below what would be expected if prices had remained at pre-policy level. Over half of the reduction in spending was due to savings on just 10 generic ingredients. If other provinces had matched Ontario’s prices, their expenditures over during the latter half of 2010 would have been $445 million lower. Discussion: We found that if Ontario’s pricing scheme were adopted nationally, overall spending on generic drugs in Canada would drop at least$1.28 billion annually—a 5 % decrease in total prescription drug expenditure. Other provinces should seriously consider both changes to their generic drug prices and the use of more competitive bulk purchasing policies

Post-Partum Pituitary Insufficiency and Livedo Reticularis Presenting a Diagnostic Challenge in a Resource Limited Setting in Tanzania: A Case Report, Clinical Discussion and Brief Review of Existing Literature.

Pituitary disorders following pregnancy are an important yet under reported clinical entity in the developing world. Conversely, post partum panhypopituitarism has a more devastating impact on women in such settings due to high fertility rates, poor obstetric care and scarcity of diagnostic and therapeutic resources available. A 37 year old African female presented ten years post partum with features of multiple endocrine deficiencies including hypothyroidism, hypoadrenalism, lactation failure and secondary amenorrhea. In addition she had clinical features of an underlying autoimmune condition. These included a history of post-partum thyroiditis, alopecia areata, livedo reticularis and deranged coagulation indices. A remarkable clinical response followed appropriate hormone replacement therapy including steroids. This constellation has never been reported before; we therefore present an interesting clinical discussion including a brief review of existing literature. Post partum pituitary insufficiency is an under-reported condition of immense clinical importance especially in the developing world. A high clinical index of suspicion is vital to ensure an early and correct diagnosis which will have a direct bearing on management and patient outcome