The Rotation of the halo of NGC 6822 from the radial velocities of carbon stars

© The Authors 2016. Published by Oxford University Press on behalf of The Royal Astronomical Society. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.Using spectra taken with the AAOmega spectrograph, we measure the radial velocities of over 100 stars, many of which are intermediate age carbon stars, in the direction of the dwarf irregular galaxy NGC 6822. Kinematic analysis suggests that the carbon stars in the sample are associated with NGC 6822, and estimates of its radial velocity and galactic rotation are made from a star-by-star analysis of its carbon star population. We calculate a heliocentric radial velocity for NGC 6822 of −51±3 kms-1 and show that the population rotates with a mean rotation speed of 11.2±2.1 kms-1 at a mean distance of 1.1 kpc from the galactic centre, about a rotation axis with a position angle of 26 ∘ ±13 ∘ , as projected on the sky. This is close to the rotation axis of the HI gas disk and suggests that NGC 6822 is not a polar ring galaxy, but is dynamically closer to a late type galaxy. However, the rotation axis is not aligned with the minor axis of the AGB isodensity profiles and this remains a mystery.Peer reviewe

Reaching the Poor: The 'Costs' of Sending Children to School: A Six Country Comparative Study, Synthesis Report

Teaching/Communication/Extension/Profession,

Isolation and characterisation of the chick orthologue of the Opitz syndrome gene, Mid1, supports a conserved role in vertebrate development

© UBC PressThe X-linked form of Opitz syndrome (OS) is caused by loss of function of the microtubule-associated MID1 protein. The phenotype of OS includes defects along the central body axis, namely hypertelorism, cleft lip and palate, hypospadias and cardiac structural anomalies. Here we describe the isolation and characterisation of full-length cDNA clones representing the chick Mid1 gene and the detailed profile of its expression in stage 7 to 28 chick embryos. Consistent with the remarkable sequence conservation of MID1 between human and chick was the good correlation of the pattern of cMid1 expression with the tissues affected in OS. In stage 10 embryos, transcripts were concentrated in the head mesenchyme which includes migratory neural crest cells. However, the incomplete overlap with a neural crest marker, Sox10, suggests that Mid1 is a marker for somitomeric mesoderm and potentially for a subset of neural crest cells. Consistent with this, cMid1 expression was also detected at later stages in neural crest-derived facial mesenchyme, in the myotome and in the condensing muscle blocks of the limb. Expression of cMid1 was observed in the neural epithelium of the forebrain beginning at stage 7 with increased signal in presumptive rhombomeres 2/3. By stage 15, expression is highest in the diencephalon. Other areas with high expression are certain facial epithelia and the midgut that will give rise to the oesophagus and trachea. These data indicate that Mid1 plays an evolutionarily conserved developmental function in vertebrates that may involve effects on cellular proliferation, tissue interactions and morphogenesis.Joy M. Richman, Katherine K. Fu, Liza L. Cox, Jane P. Sibbons and Timothy C. Co

Spectral classification of photometrically selected AGB candidates in NGC 6822

© 2014 ESO. Reproduced with permission from Astronomy & Astrophysics. Content in the UH Research Archive is made available for personal research, educational, and non-commercial purposes only. Unless otherwise stated, all content is protected by copyright, and in the absence of an open license, permissions for further re-use should be sought from the publisher, the author, or other copyright holder.Context. The ratio of C- and M-type asymptotic giant branch (AGB) stars is commonly used to estimate the metallicity of extragalactic populations. Sources in the AGB population must therefore be accurately classified as either C- or M-type. Spectroscopic data are presented for candidate C- and M-type AGB stars, previously classified using JHK photometry, in the Local Group dwarf galaxy NGC 6822. Aims. This paper aims to evaluate the success of the JHK classification criteria used in order to determine the level of error associated with this method, and to refine the criteria for future studies. The success rate of a second independent method of source classification, the CN–TiO method, is also examined. We also review the validity of the 4 kpc radial limit imposed in our previous work. Methods. Spectra of 323 sources, distributed across an area of 2 deg2, were taken using the AAOmega multi-fibre spectrograph on the Anglo-Australian Telescope and have been classified using an automated classification system and spectral standards from the literature. Nearly half (135) of these sources were selected in common with a photometric catalogue that relied on the CN–TiO method. Results. Within this sample we were able to classify 158 sources, including 82 C-type giants and one anomalous M-type giant, all members of NGC 6822, and 75 foreground K- and M-type dwarf sources. All but three of the giant sources are located within 3 kpc of the galactic centre. Using this spectroscopic sample, new JHK photometric criteria for the isolation and classification of C- and M-type AGB stars have been derived. The error rate in the CN–TiO method, arising from stars incorrectly classified as C-type, has been estimated to be ~7%. Conclusions. Based on the new JHK classification criteria, revised estimates of the global C/M ratio, 0.95 ± 0.04, and iron abundance, −1.38 ± 0.06 dex, are presented for NGC 6822.Peer reviewe

A genome-wide association study demonstrates significant genetic variation for fracture risk in Thoroughbred racehorses

Background: Thoroughbred racehorses are subject to non-traumatic distal limb bone fractures that occur during racing and exercise. Susceptibility to fracture may be due to underlying disturbances in bone metabolism which have a genetic cause. Fracture risk has been shown to be heritable in several species but this study is the first genetic analysis of fracture risk in the horse. Results: Fracture cases (n = 269) were horses that sustained catastrophic distal limb fractures while racing on UK racecourses, necessitating euthanasia. Control horses (n = 253) were over 4 years of age, were racing during the same time period as the cases, and had no history of fracture at the time the study was carried out. The horses sampled were bred for both flat and National Hunt (NH) jump racing. 43,417 SNPs were employed to perform a genome-wide association analysis and to estimate the proportion of genetic variance attributable to the SNPs on each chromosome using restricted maximum likelihood (REML). Significant genetic variation associated with fracture risk was found on chromosomes 9, 18, 22 and 31. Three SNPs on chromosome 18 (62.05 Mb – 62.15 Mb) and one SNP on chromosome 1 (14.17 Mb) reached genome-wide significance (p <0.05) in a genome-wide association study (GWAS). Two of the SNPs on ECA 18 were located in a haplotype block containing the gene zinc finger protein 804A (ZNF804A). One haplotype within this block has a protective effect (controls at 1.95 times less risk of fracture than cases, p = 1 × 10-4), while a second haplotype increases fracture risk (cases at 3.39 times higher risk of fracture than controls, p = 0.042). Conclusions: Fracture risk in the Thoroughbred horse is a complex condition with an underlying genetic basis. Multiple genomic regions contribute to susceptibility to fracture risk. This suggests there is the potential to develop SNP-based estimators for genetic risk of fracture in the Thoroughbred racehorse, using methods pioneered in livestock genetics such as genomic selection. This information would be useful to racehorse breeders and owners, enabling them to reduce the risk of injury in their horses

Decellularised cartilage directs chondrogenic differentiation: creation of a fracture callus mimetic

Complications that arise from impaired fracture healing have considerable socioeconomic implications. Current research in the field of bone tissue engineering predominantly aims to mimic the mature bone tissue microenvironment. This approach, however, may produce implants that are intrinsically unresponsive to the cues present during the initiation of fracture repair. As such, this study describes the development of decellularised xenogeneic hyaline cartilage matrix in an attempt to mimic the initial reparative phase of fracture repair. Three approaches based on vacuum-assisted osmotic shock (Vac-OS), Triton X (Vac-Stx) and SDS (Vac-SDS) were investigated. The Vac-OS methodology reduced DNA content below 50ng/mg of tissue, whilst retaining 85% of the sGAG content and as such was selected as the optimal methodology for decellularisation. The resultant Vac-OS scaffolds (dcECM) were also devoid of the immunogenic alpha-gal epitope. Furthermore, minimal disruption to the structural integrity of the dcECM was demonstrated using differential scanning calorimetry (DSC) and fluorescence lifetime imaging microscopy (FLIM). The biological integrity of the dcECM was confirmed by its ability to drive the chondrogenic commitment and differentiation of human chondrocytes and periosteum-derived cells respectively. Furthermore, histological examination of dcECM constructs implanted in immunocompetent mice revealed a predominantly M2-macrophage driven regenerative response both at 2 and 8 weeks post-implantation. These findings contrasted with the implanted native costal cartilage that elicited a predominantly M1-macrophage mediated inflammatory response. This study highlights the capacity of dcECM from the Vac-OS methodology to direct the key biological processes of endochondral ossification, thus potentially recapitulating the callus phase of fracture repair

Mechanisms underlying heterologous skin scaffold-mediated tissue remodeling

Biocompatibility of two newly developed porcine skin scaffolds was assessed after 3, 14, 21 and 90 days of implantation in rats. Both scaffolds showed absence of cells, preservation of ECM and mechanical properties comparable to non-decellularised skin before implantation. Host cell infiltration was much prominent on both scaffolds when compared to Permacol (surgical control). At day 3, the grafts were surrounded by polymorphonuclear cells, which were replaced by a notable number of IL-6-positive cells at day 14. Simultaneously, the number of pro-inflammatory M1-macrophage was enhanced. Interestingly, a predominant pro-remodeling M2 response, with newly formed vessels, myofibroblasts activation and a shift on the type of collagen expression was sequentially delayed (around 21 days). The gene expression of some trophic factors involved in tissue remodeling was congruent with the cellular events. Our findings suggested that the responsiveness of macrophages after non-crosslinked skin scaffolds implantation seemed to intimately affect various cell responses and molecular eventsand this range of mutually reinforcing actions was predictive of a positive tissue remodeling that was essential for the long-standing success of the implants. Furthermore, our study indicates that non-crosslinked biologic scaffold implantation is biocompatible to the host tissue and somehow underlying molecular events involved in tissue repair.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fed Univ Sao Paulo UNIFESP, Postgrad Struct & Funct Biol, BR-04023900 Sao Paulo, SP, BrazilSao Paulo State Univ UNESP, Dept Biol, BR-15054000 Sao Jose Do Rio Preto, SP, BrazilSao Paulo State Univ UNESP, Inst Biociencias Letras & Ciencias Exatas, BR-15054000 Sao Jose Do Rio Preto, SP, BrazilUCL, Northwick Pk Inst Med Res, Dept Surg Res, London HA1 3UJ, Middx, EnglandPost-Graduation in Structural and Functional Biology, Universidade Federal de São Paulo (UNIFESP), São Paulo, SP, 04023-900, BrazilFAPESP: 2012/21603-2FAPESP: 2012/13041-4FAPESP: 2014/18557-4CNPq: 308144/2014-7CNPq: 245859/2012-8Web of Scienc

Arachidonic acid and DHA status in pregnant women is not associated with cognitive performance of their children at 4 or 6–7 years

Arachidonic acid (ARA) and DHA, supplied primarily from the mother, are required for early development of the central nervous system. Thus, variations in maternal ARA or DHA status may modify neurocognitive development. We investigated the relationship between maternal ARA and DHA status in early (11·7 weeks) or late (34·5 weeks) pregnancy on neurocognitive function at the age of 4 years or 6–7 years in 724 mother–child pairs from the Southampton Women’s Survey cohort. Plasma phosphatidylcholine fatty acid composition was measured in early and late pregnancy. ARA concentration in early pregnancy predicted 13 % of the variation in ARA concentration in late pregnancy (β=0·36, P&lt;0·001). DHA concentration in early pregnancy predicted 21 % of the variation in DHA concentration in late pregnancy (β=0·46, P&lt;0·001). Children’s cognitive function at the age of 4 years was assessed by the Wechsler Preschool and Primary Scale of Intelligence and at the age of 6–7 years by the Wechsler Abbreviated Scale of Intelligence. Executive function at the age of 6–7 years was assessed using elements of the Cambridge Neuropsychological Test Automated Battery. Neither DHA nor ARA concentrations in early or late pregnancy were associated significantly with neurocognitive function in children at the age of 4 years or the age of 6–7 years. These findings suggest that ARA and DHA status during pregnancy in the range found in this cohort are unlikely to have major influences on neurocognitive function in healthy children.</p