Cosmic Sculpture: A new way to visualise the Cosmic Microwave Background

3D printing presents an attractive alternative to visual representation of physical datasets such as astronomical images that can be used for research, outreach or teaching purposes, and is especially relevant to people with a visual disability. We here report the use of 3D printing technology to produce a representation of the all-sky Cosmic Microwave Background (CMB) intensity anisotropy maps produced by the Planck mission. The success of this work in representing key features of the CMB is discussed as is the potential of this approach for representing other astrophysical data sets. 3D printing such datasets represents a highly complementary approach to the usual 2D projections used in teaching and outreach work, and can also form the basis of undergraduate projects. The CAD files used to produce the models discussed in this paper are made available.Comment: Accepted for publication in the European Journal of Physic

Components required for in vitro cleavage and polyadenylation of eukaryotic mRNA

We have studied in vitro cleavage/polyadenylation of precursor RNA containing herpes simplex virus type 2 poly A site sequences and have analysed four RNA/protein complexes which form during in vitro reactions. Two complexes, A and B, form extremely rapidly and are then progressively replaced by a third complex, C which is produced following cleavage and polyadenylation of precursor RNA. Substitution of ATP with cordycepin triphosphate prevents polyadenylation and the formation of complex C however a fourth complex, D, results which contains cleaved RNA. A precursor RNA lacking GU-rich downstream sequences required for efficient cleavage/ polyadenylation fails to form complex B and produces a markedly reduced amount of complex A. As these GU-rich sequences are required for efficient cleavage, this establishes a relationship between complex B formation and cleavage/polyadenylation of precursor RNA in vitro. The components required for in vitro RNA processing have been separated by fractionation of the nuclear extract on Q-Sepharose and Biorex 70 columns. A Q-Sepharose fraction forms complex B but does not process RNA. Addition of a Biorex 70 fraction restores cleavage activity at the poly A site but this fraction does not appear to contribute to complex formation. Moreover, in the absence of polyethylene glycol, precursor RNA is not cleaved and polyadenylated, however, complexes A and B readily form. Thus, while complex B is necessary for in vitro cleavage and polyadenylation, it may not contain all the components required for this processing

Impacts of Protected Areas on Local Livelihoods in Cambodia

SummaryImpact evaluation methods (mixed effects models and matching) were used to investigate the effect of protected areas (PAs) on poverty and livelihoods in Cambodia, comparing households inside PAs with bordering villages and controls. There was no evidence that PAs exacerbated local poverty or reduce agricultural harvests in comparison with controls. Households bordering the PAs were significantly better off due to greater access to markets and services. Non-timber forest product (NTFP) collectors inside PAs were significantly better off than controls and had greater rice harvests, because they had more secure access to land and forest resources. The PAs in Cambodia therefore have some positive impacts on households that use forest and land resources for their livelihoods

Candidate High Redshift and Primeval Galaxies in Hubble Deep Field South

We present the results of colour selection of candidate high redshift galaxies in Hubble Deep Field South (HDF-S) using the Lyman dropout scheme. The HDF-S data we discuss were taken in a number of different filters extending from the near--UV (F300W) to the infrared (F222M) in two different fields. This allows us to select candidates with redshifts from z~3 to z~12. We find 15 candidate z~3 objects (F300W dropouts), 1 candidate z~4 object (F450W dropout) and 16 candidate z$\sim$5 objects (F606W dropouts) in the ~ 4.7 arcmin^2 WFPC-2 field, 4 candidate z~6 (optical dropouts) and 1 candidate z~8 (F110W dropout) in the 0.84 arcmin^2 NICMOS-3 field. No F160W dropouts are found (z~12). We compare our selection technique with existing data for HDF-North and discuss alternative interpretations of the objects. We conclude that there are a number of lower redshift interlopers in the selections, including one previously identified object (Treu et al. 1998), and reject those objects most likely to be foreground contaminants. Even after this we conclude that the F606W dropout list is likely to still contain substantial foreground contamination. The lack of candidate very high redshift UV-luminous galaxies supports earlier conclusions by Lanzetta et al. (1998). We discuss the morphologies and luminosity functions of the high redshift objects, and their cosmological implications.Comment: Accepted for publication in MNRA

Preasymptotic multiscaling in the phase-ordering dynamics of the kinetic Ising model

The evolution of the structure factor is studied during the phase-ordering dynamics of the kinetic Ising model with conserved order parameter. A preasymptotic multiscaling regime is found as in the solution of the Cahn-Hilliard-Cook equation, revealing that the late stage of phase-ordering is always approached through a crossover from multiscaling to standard scaling, independently from the nature of the microscopic dynamics.Comment: 11 pages, 3 figures, to be published in Europhys. Let

Developing analytical distributions for temperature indices for the purposes of pricing temperature-based weather derivatives

Temperature-based weather derivatives are written on an index which is normally defined to be a nonlinear function of average daily temperatures. Recent empirical work has demonstrated the usefulness of simple time-series models of temperature for estimating the payoffs to these instruments. This paper develops analytical distributions of temperature indices on which temperature derivatives are written. If deviations of daily temperature from its expected value is modelled as an Ornstein-Uhlenbeck process with time-varying variance, then the distributions of the temperature index on which the derivative is written is the sum of truncated, correlated Gaussian deviates. The key result of this paper is to provide an analytical approximation to the distribution of this sum, thus allowing the accurate computation of payoffs without the need for any simulation. A data set comprising average daily temperature spanning over a hundred years for four Australian cities is used to demonstrate the efficacy of this approach for estimating the payoffs to temperature derivatives. It is demonstrated that expected payoffs computed directly from historical records is a particulary poor approach to the problem when there are trends in underlying average daily temperature. It is shown that the proposed analytical approach is superior to historical pricing.Weather Derivatives, Temperature Models, Cooling Degree Days, Maximum Likelihood Estimation, Distribution for Correlated Variables

Bayesian spatial analysis of a national urinary schistosomiasis questionnaire to assist geographic targeting of schistosomiasis control in Tanzania, East Africa.

Spatial modelling was applied to self-reported schistosomiasis data from over 2.5 million school students from 12,399 schools in all regions of mainland Tanzania. The aims were to derive statistically robust prevalence estimates in small geographical units (wards), to identify spatial clusters of high and low prevalence and to quantify uncertainty surrounding prevalence estimates. The objective was to permit informed decision-making for targeting of resources by the Tanzanian national schistosomiasis control programme. Bayesian logistic regression models were constructed to investigate the risk of schistosomiasis in each ward, based on the prevalence of self-reported schistosomiasis and blood in urine. Models contained covariates representing climatic and demographic effects and random effects for spatial clustering. Degree of urbanisation, median elevation of the ward and median normalised difference vegetation index (NDVI) were significantly and negatively associated with schistosomiasis prevalence. Most regions contained wards that had >95% certainty of schistosomiasis prevalence being >10%, the selected threshold for bi-annual mass chemotherapy of school-age children. Wards with >95% certainty of schistosomiasis prevalence being >30%, the selected threshold for annual mass chemotherapy of school-age children, were clustered in north-western, south-western and south-eastern regions. Large sample sizes in most wards meant raw prevalence estimates were robust. However, when uncertainties were investigated, intervention status was equivocal in 6.7-13.0% of wards depending on the criterion used. The resulting maps are being used to plan the distribution of praziquantel to participating districts; they will be applied to prioritising control in those wards where prevalence was unequivocally above thresholds for intervention and might direct decision-makers to obtain more information in wards where intervention status was uncertain

Maintenance of time and frequency in the Jet Propulsion Laboratory's Deep Space Network using the Global Positioning System

The Deep Space Network (DSN), managed by the Jet Propulsion Laboratory for NASA, must maintain time and frequency within specified limits in order to accurately track the spacecraft engaged in deep space exploration. Various methods are used to coordinate the clocks among the three tracking complexes. These methods include Loran-C, TV Line 10, Very Long Baseline Interferometry (VLBI), and the Global Positioning System (GPS). Calculations are made to obtain frequency offsets and Allan variances. These data are analyzed and used to monitor the performance of the hydrogen masers that provide the reference frequencies for the DSN Frequency and Timing System (DFT). Areas of discussion are: (1) a brief history of the GPS timing receivers in the DSN, (2) a description of the data and information flow, (3) data on the performance of the DSN master clocks and GPS measurement system, and (4) a description of hydrogen maser frequency steering using these data