Null tests of the cosmological constant using supernovae

The standard concordance model of the Universe is based on the cosmological constant as the driver of accelerating expansion. This concordance model is being subjected to a growing range of inter-locking observations. In addition to using generic observational tests, one can also design tests that target the specific properties of the cosmological constant. These null tests do not rely on parametrizations of observables, but focus on quantities that are constant only if dark energy is a cosmological constant. We use supernova data in null tests that are based on the luminosity distance. In order to extract derivatives of the distance in a model-independent way, we use Gaussian Processes. We find that the concordance model is compatible with the Union 2.1 data, but the error bars are fairly large. Simulated datasets are generated for the DES supernova survey and we show that this survey will allow for a sharper null test of the cosmological constant if we assume the Universe is flat. Allowing for spatial curvature degrades the power of the null test.IS

UBVRIz Light Curves of 51 Type II Supernovae

We present a compilation of UBV RIz light curves of 51 type II supernovae discovered during the course of four different surveys during 1986 to 2003: the Cerro Tololo Supernova Survey, the Calan/Tololo Supernova Program (C&T), the Supernova Optical and Infrared Survey (SOIRS), and the Carnegie Type II Supernova Survey (CATS). The photometry is based on template-subtracted images to eliminate any potential host galaxy light contamination, and calibrated from foreground stars. This work presents these photometric data, studies the color evolution using different bands, and explores the relation between the magnitude at maximum brightness and the brightness decline parameter (s) from maximum light through the end of the recombination phase. This parameter is found to be shallower for redder bands and appears to have the best correlation in the B band. In addition, it also correlates with the plateau duration, being thus shorter (longer) for larger (smaller) s values.Comment: 110 pages, 9 Figures, 6 Tables, accepted in A

Identification, characterisation and expression analysis of natural killer receptor genes in Chlamydia pecorum infected koalas (Phascolarctos cinereus)

BACKGROUND: Koalas (Phascolarctos cinereus), an iconic Australian marsupial, are being heavily impacted by the spread of Chlamydia pecorum, an obligate intracellular bacterial pathogen. Koalas vary in their response to this pathogen, with some showing no symptoms, while others suffer severe symptoms leading to infertility, blindness or death. Little is known about the pathology of this disease and the immune response against it in this host. Studies have demonstrated that natural killer (NK) cells, key components of the innate immune system, are involved in the immune response to chlamydial infections in humans. These cells can directly lyse cells infected by intracellular pathogens and their ability to recognise these infected cells is mediated through NK receptors on their surface. These are encoded in two regions of the genome, the leukocyte receptor complex (LRC) and the natural killer complex (NKC). These two families evolve rapidly and different repertoires of genes, which have evolved by gene duplication, are seen in different species. METHODS: In this study we aimed to characterise genes belonging to the NK receptor clusters in the koala by searching available koala transcriptomes using a combination of search methods. We developed a qPCR assay to quantify relative expression of four genes, two encoded within the NK receptor cluster (CLEC1B, CLEC4E) and two known to play a role in NK response to Chalmydia in humans (NCR3, PRF1). RESULTS: We found that the NK receptor repertoire of the koala closely resembles that of the Tasmanian devil, with minimal genes in the NKC, but with lineage specific expansions in the LRC. Additional genes important for NK cell activity, NCR3 and PRF1, were also identified and characterised. In a preliminary study to investigate whether these genes are involved in the koala immune response to infection by its chlamydial pathogen, C. pecorum, we investigated the expression of four genes in koalas with active chlamydia infection, those with past infection and those without infection using qPCR. This analysis revealed that one of these four, CLEC4E, may be upregulated in response to chlamydia infection. CONCLUSION: We have characterised genes of the NKC and LRC in koalas and have discovered evidence that one of these genes may be upregulated in koalas with chlamydia, suggesting that these receptors may play a role in the immune response of koalas to chlamydia infection

BVRI Light Curves for 29 Type Ia Supernovae

BVRI light curves are presented for 27 Type Ia supernovae discovered during the course of the Calan/Tololo Survey and for two other SNe Ia observed during the same period. Estimates of the maximum light magnitudes in the B, V, and I bands and the initial decline rate parameter m15(B) are also given.Comment: 17 pages, figures and tables are not included (contact first author if needed), to appear in the Astronomical Journa

Investigating the depression-anxiety link in clients receiving Integrative Counselling

Objective: The aim of this paper was to investigate how anxiety and depression impact upon each other over the course of a counselling intervention. Method: A single-group repeated measures quasi-experimental design was employed. Data were collected at four time points: at pre-therapy assessment and at first, third, and last sessions. The sample consisted of 562 predominantly white British clients receiving Integrative Counselling at North Kent Mind, UK. Two measures were used: the Generalised Anxiety Disorder Scale to measure anxiety and the Patient Health Questionnaire to measure depression. Results: Clients improved in both dimensions at every measurement point. Path analysis suggested that anxiety and depression remained interlinked throughout treatment but they presented different effect profiles. They both appeared to have a premature effect on the other, but they did so in different ways. Conclusions: The therapeutic relationship may be a crucial factor in understanding the  premature effect observed and future research should utilise direct measures of the relationship.

Effect of Nano-Silica on the Physical, Mechanical and Thermal Properties of the Natural Rubber Latex Modified Concrete

The preparation and properties of latex modified concrete (LMC), nano silica modified concrete (nSMC) and silica-latex modified concrete (SLMC) have been investigated in this study. Properties like compressive strength, tensile strength, flexural strength, thermal characteristics and water absorption have been evaluated. The 7-day compressive strength has increased 37% (30.15 N/mm2) after the inclusion of nano silica and latex. The composite has showed considerable improvements in splitting tensile strength (3.24 N/mm2), flexural strength (6.05 N/mm2) and thermal conductivity, while it lowered the water absorption rate. The property increase has been attributed to the pore filling and pozzolanic activity of nano silica and densification of matrix by natural rubber latex and nano silica. The results of this study have suggested that the addition of nano silica and latex could be a relevant technique toward conventional concrete as a key material along with energy efficient construction and building technology

Effect of Nano-Silica on the Physical, Mechanical and Thermal Properties of the Natural Rubber Latex Modified Concrete

452-457The preparation and properties of latex modified concrete (LMC), nano silica modified concrete (nSMC) and silica-latex modified concrete (SLMC) have been investigated in this study. Properties like compressive strength, tensile strength, flexural strength, thermal characteristics and water absorption have been evaluated. The 7-day compressive strength has increased 37% (30.15 N/mm2) after the inclusion of nano silica and latex. The composite has showed considerable improvements in splitting tensile strength (3.24 N/mm2), flexural strength (6.05 N/mm2) and thermal conductivity, while it lowered the water absorption rate. The property increase has been attributed to the pore filling and pozzolanic activity of nano silica and densification of matrix by natural rubber latex and nano silica. The results of this study have suggested that the addition of nano silica and latex could be a relevant technique toward conventional concrete as a key material along with energy efficient construction and building technology