On the Delta V_HB_bump parameter in Globular Clusters (2010)
Di Cecco, A., Bono, G., Stetson, P. B., Pietrinferni, A., Becucci, R., Cassisi, S., ...
We present new empirical estimates of the Delta V_HB_bump parameter for 15 Galactic globular clusters (GGCs) using accurate and homogeneous ground-based optical data. Together with similar...
Bono, G., Stetson, P. B., VandenBerg, D. A., Calamida, A., Dall'Ora, M., Iannicola, G., ...
We present a new method to estimate the absolute ages of stellar systems. This method is based on the difference in magnitude between the main sequence turn-off (MSTO) and a well defined knee located...
Rest, A., Foley, R. J., Gezari, S., Narayan, G., Draine, B., Olsen, K., ...
We report the discovery of a supernova (SN) with the highest apparent energy output to date and conclude that it represents an extreme example of the Type IIn subclass. The SN, which was discovered...
Calamida, A., Bono, G., Stetson, P. B., Freyhammer, L. M., Piersimoni, A. M., Buonanno, R., ...
We present new intermediate-band Stroemgren photometry based on more than 300 u,v,b,y images of the Galactic globular cluster Omega Cen. Optical data were supplemented with new multiband...
On the stellar content of the starburst galaxy IC10 (2009)
Sanna, N., Bono, G., Stetson, P. B., Pietrinferni, A., Monelli, M., Cassisi, S., ...
We investigate the stellar content of the starburst dwarf galaxy IC10 using accurate and deep optical data collected with the Advanced Camera for Surveys and with the Wide Field Planetary Camera 2 on...
On the radial distribution of horizontal branch stars in ngc2808 (2009)
Iannicola, G., Monelli, M., Bono, G., Buonanno, P. B. Stetson R., Calamida, A., Zoccali, M., ...
We present accurate new ultraviolet and optical BVI photometry for the Galactic globular cluster ngc2808, based on both ground-based and archival HST imagery. From this we have selected a sample of...
On the distance and reddening of the starburst galaxy IC10 (2008)
Sanna, N., Bono, G., Stetson, P. B., Monelli, M., Pietrinferni, A., Drozdovsky, I., ...
We present deep and accurate optical photometry of the Local Group starburst galaxy IC10. The photometry is based on two sets of images collected with the Advanced Camera for Surveys and with the...
Relative distances of Omega Centauri and 47 Tucanae (2008)
Bono, G., Stetson, P. B., Sanna, N., Piersimoni, A., Freyhammer, L. M., Bouzid, Y., ...
We present precise optical and near-infrared ground-based photometry of two Globular Clusters (GCs): Omega Cen and 47 Tuc. These photometric catalogs are unbiased in the Red Giant Branch (RGB) region...
Endophytic Actinobacteria Induce Defense Pathways in Arabidopsis thaliana (2008)
Conn, Vanessa Michelle, Walker, A. R., Franco, C. M. M.
Endophytic actinobacteria, isolated from healthy wheat tissue, which are capable of suppressing a number wheat fungal pathogens both in vitro and in planta, were investigated for the ability to...
Endophytic Actinobacteria Induce Defense Pathways in Arabidopsis thaliana (2008)
Conn, Vanessa Michelle, Walker, A. R., Franco, C. M. M.
Endophytic actinobacteria, isolated from healthy wheat tissue, which are capable of suppressing a number wheat fungal pathogens both in vitro and in planta, were investigated for the ability to...
Endophytic Actinobacteria Induce Defense Pathways in Arabidopsis thaliana (2008)
Conn, Vanessa Michelle, Walker, A. R., Franco, Christopher M. M.
Endophytic actinobacteria, isolated from healthy wheat tissue, which are capable of suppressing a number wheat fungal pathogens both in vitro and in planta, were investigated for the ability to...
Light-induced expression of a MYB gene regulates anthocyanin biosynthesis in red apples (2006)
Takos, A. M., Jaffe, F. W., Jacob, S. R., Bogs, J., Robinson, S. P., Walker, A. R.
B, V, I photometry of the complete sample of 23 Cepheids in the field of NGC 1866 (2005)
Musella, I., Ripepi, V., Brocato, E., Castellani, V., Caputo, F., Del Principe, M., ...
We present the result of BVI photometry, obtained by using FORS@VLT, of the Cepheids present in the field of the Large Magellanic Cloud cluster NGC 1866. We found the 22 known variables plus an...
The Carina dSph galaxy: where is the edge? (2005)
Bono, G., Monelli, M., Walker, A. R., Munteanu, A., Buonanno, R., Caputo, F., ...
Recent cosmological N-body simulations suggest that current empirical estimates of tidal radii in dSphs might be underestimated by at least one order of magnitude. To constrain the plausibility of...
Humphries, John Andrew, Walker, A. R., Timmis, Jeremy Newman, Orford, Sharon Josephine
Cotton fibres are single, highly elongated cells derived from the outer epidermis of ovules, and are developmentally similar to the trichomes of Arabidopsis thaliana. To identify genes involved in...
Humphries, John Andrew, Walker, A. R., Timmis, Jeremy Newman, Orford, Sharon Josephine
Cotton fibres are single, highly elongated cells derived from the outer epidermis of ovules, and are developmentally similar to the trichomes of Arabidopsis thaliana. To identify genes involved in...
Humphries, John Andrew, Walker, A. R., Timmis, Jeremy Newman, Orford, Sharon Josephine
Cotton fibres are single, highly elongated cells derived from the outer epidermis of ovules, and are developmentally similar to the trichomes of Arabidopsis thaliana. To identify genes involved in...
The Carina Project: II. Stellar Populations (2003)
Monelli, M., Pulone, L., Corsi, C. E., Castellani, M., Bono, G., Walker, A. R., ...
We present a new (V,B-V) Color-Magnitude Diagram (CMD) of the Carina dwarf spheroidal (dSph) that extends from the tip of the Red Giant Branch (RGB) down to about V=25 mag. Data were collected with...
The luminosity function of the Large Magellanic Cloud globular cluster NGC 1866 (2003)
Brocato, E., Castellani, V., Di Carlo, E., Raimondo, G., Walker, A. R.
We present {\it Hubble Space Telescope} {\it V,I} photometry of the central region of the LMC cluster NGC 1866, reaching magnitudes as faint as V=27 mag. We find evidence that the cluster luminosity...
The Carina Project: I. Bright Variable Stars (2003)
Dall'Ora, M., Ripepi, V., Caputo, F., Castellani, V., Bono, G., Smith, H. A., ...
We present new BV time series data of the Carina dwarf spheroidal galaxy. Current data cover an area of about 0.3 square degrees around the center of the galaxy and allowed us to identify 92...
The distance to the LMC cluster NGC 1866 and the surrounding field (2003)
Salaris, M., Percival, S., Brocato, E., Raimondo, G., Walker, A. R.
We use the Main Sequence stars in the LMC cluster NGC 1866 and of Red Clump stars in the local field to obtain two independent estimates of the LMC distance. We apply an empirical Main...
"The Carina Project": color magnitude diagram and radial distribution (2003)
Castellani, M., Bono, G., Buonanno, R., Caputo, F., Castellani, V., Corsi, C. E., ...
We present B, V photometric data of the Carina Dwarf Spheroidal Galaxy collected with the Wide Field Imager (WFI) available at the 2.2m MPI/ESO telescope. We briefly discuss the main features of the...
Bersier, D., Stanek, K. Z., Winn, J., Grav, T., Holman, M. J., Matheson, T., ...
We report UBVRI observations of the optical afterglow of the gamma-ray burst GRB 021004. We observed significant (10-20%) deviations from a power law decay on several time scales, ranging from a few...
NGC1866: New analysis from HST-WFPC2 observations of the inner regions (2002)
Di Carlo, E., Raimondo, G., Brocato, E., Castellani, V., Walker, A. R.
We report new results on the LMC globular cluster NGC 1866 obtained by analyzing F555W and F814W images from WFPC2@HST. On the basis of the CMD we derive information on the cluster distance and...
The Distance of the Large Magellanic Cloud Cluster NGC 1866 (2001)
Walker, A. R., Raimondo, G., Di Carlo, E., Brocato, E., Castellani, V., Hill, V.
Hubble Space Telescope V,I photometry of stars in the Large Magellanic Cloud Cluster NGC 1866 shows a well defined cluster main sequence down to V=25 mag, with little contamination from field or...
Old Stellar Populations of the Small Magellanic Cloud (2001)
Dolphin, A. E., Walker, A. R., Hodge, P. W., Mateo, M., Olszewski, E. W., Schommer, R. A., ...
We present WFPC2 and ground-based VI photometry of NGC 121 and a nearby field in the outer SMC. For NGC 121, we measure a true distance modulus of (m-M)0 = 18.96 +/- 0.04 (distance of 61.9 +/- 1.1...
Empirical relations for cluster RR Lyrae stars revisited (2001)
Our former study on the empirical relations between the Fourier parameters of the light curves of the fundamental mode RR Lyrae stars and their basic stellar parameters has been extended to...
Ischemic heart disease in black South African stroke patients (2000)
Joubert, J., McLean, C. A., Reid, C., Davel, D. D., Pilloy, W. D., Delport, R., ...
Ischemic heart disease in black South African stroke patients (2000)
Joubert, J., McLean, C. A., Reid, C., Davel, D. D., Pilloy, W. D., Delport, R., ...
Ischemic heart disease in black South African stroke patients (2000)
Joubert, J., McLean, C. A., Reid, C., Davel, D. D., Pilloy, W. D., Delport, R., ...
Multiple stellar populations in the globular cluster ω Centauri as tracers of a merger event (1999)
Y.-W. Lee, J.-M. Joo, Y.-J. Sohn, S.-C. Rey, H.-c. Lee, A. R. Walker
An Extremely Red r^{1/4} Galaxy in the Test Image of the Hubble Deep Field South (1998)
Treu, T., Stiavelli, M., Walker, A. R., Williams, R. E., Baum, S. A., Bernstein, G., ...
We report the serendipitous discovery of an extremely red object in the Hubble Deep Field South (HDFS) Test NICMOS (Near Infrared Camera and Multi Object Spectrograph) field of view. The object is...
HST Colour-Magnitude Diagrams of Six Old Globular Clusters in the LMC (1998)
Olsen, K. A. G., Hodge, P. W., Mateo, M., Olszewski, E. W., Schommer, R. A., Suntzeff, N. B., ...
We report on HST observations of six candidate old globular clusters in the Large Magellanic Cloud: NGC 1754, NGC 1835, NGC 1898, NGC 1916, NGC 2005 and NGC 2019. Deep exposures with the F555W and...
Lavery, R. J., Seitzer, P., Suntzeff, N. B., Walker, A. R., Da Costa, G. S.
Hubble Space Telescope WFPC2 images of the Local Group dwarf galaxy Tucana reveal an unbiased sample of distant field galaxies. While a large number of these galaxies can be classified according to...
Development of the sem and stem for materials studies. (1982)
Thesis (Ph. D.)--University of Oxford, 1982.
Seaports and development in the Persian Gulf. (1981)
Thesis (Ph. D.)--University of Durham, 1981.
Walker, A R, Davison, P A, Bolognesi-Winfield, A C, James, C M, Srinivasan, N, Blundell, T L, ...
The TRANSPARENT TESTA GLABRA1 (TTG1) locus regulates several developmental and biochemical pathways in Arabidopsis, including the formation of hairs on leaves, stems, and roots, and the production of...
Blood cholesterol and coronary heart disease: changing perspectives.
There has been much controversy concerning the value of efforts to reduce blood cholesterol levels. In this contribution, the risks and benefits of interventions are discussed. Lowering cholesterol...
Cancer outlook: an African perspective.
In all western populations, mortality rates from cancer are high and even increasing: moreover, incidence rates of some cancers are also rising. As to propitiousness of preventive factors, genetic,...
Coronary heart disease: outlook for Africa.
In Africa, coronary heart disease (CHD) is near absent in rural areas, and very uncommon in urban centres, where many Africans are in an advanced stage of transition. Among town dwellers intakes of...
Larkin, J C, Walker, J D, Bolognesi-Winfield, A C, Gray, J C, Walker, A R
Trichome development in Arabidopsis thaliana is a well-characterized model for the study of plant cell differentiation. Two genes that play an essential role in the initiation of trichome development...
The serum concentration of high-density lipoprotein cholesterol and the proportion it constitutes of total serum cholesterol are high in children and low in sufferers from coronary heart disease...
Walker, A R, Davison, P A, Bolognesi-Winfield, A C, James, C M, Srinivasan, N, Blundell, T L, ...
The TRANSPARENT TESTA GLABRA1 (TTG1) locus regulates several developmental and biochemical pathways in Arabidopsis, including the formation of hairs on leaves, stems, and roots, and the production of...
Blood cholesterol and coronary heart disease: changing perspectives.
There has been much controversy concerning the value of efforts to reduce blood cholesterol levels. In this contribution, the risks and benefits of interventions are discussed. Lowering cholesterol...
Cancer outlook: an African perspective.
In all western populations, mortality rates from cancer are high and even increasing: moreover, incidence rates of some cancers are also rising. As to propitiousness of preventive factors, genetic,...
Coronary heart disease: outlook for Africa.
In Africa, coronary heart disease (CHD) is near absent in rural areas, and very uncommon in urban centres, where many Africans are in an advanced stage of transition. Among town dwellers intakes of...
Larkin, J C, Walker, J D, Bolognesi-Winfield, A C, Gray, J C, Walker, A R
Trichome development in Arabidopsis thaliana is a well-characterized model for the study of plant cell differentiation. Two genes that play an essential role in the initiation of trichome development...
The serum concentration of high-density lipoprotein cholesterol and the proportion it constitutes of total serum cholesterol are high in children and low in sufferers from coronary heart disease...
Alternative pathways for hydrogen disposal during fermentation in the human colon.
Gibson, G R, Cummings, J H, Macfarlane, G T, Allison, C, Segal, I, Vorster, H H, ...
Hydrogen gas, which is produced during fermentation in the human colon, is either excreted in breath or metabolised by gut bacteria through a variety of pathways. These may include methanogenesis,...
Limitations of faecal chymotrypsin as a screening test for chronic pancreatitis.
Riedel, L, Walker, A R, Segal, I, Mohamed, A E, Smyth, A E, Daya, B, ...
Faecal chymotrypsin was measured in patients with chronic pancreatitis and in healthy black urban and rural control subjects. In the patients, significantly lower values of faecal chymotrypsin were...
Breath methane and large bowel cancer risk in contrasting African populations.
Segal, I, Walker, A R, Lord, S, Cummings, J H
Breath methane has been measured in 1016 people from four populations resident in Southern Africa which experience widely different risks of bowel cancer and other colonic diseases. Highly...
Effect of subject age on costs of screening for colorectal cancer.
Whynes, D K, Walker, A R, Hardcastle, J D
STUDY OBJECTIVE--The aim was to estimate costs and yields of faecal occult blood screening and rescreening for colorectal cancer, for differing age cohorts. DESIGN--Cost and clinical data were used...
Bowel behaviour in young black and white children.
Bowel behaviour was investigated in 81 rural black, 117 urban black, and 77 white children aged 1 to 4 years. The study was undertaken principally because intake of dietary fibre by urban blacks is...
Screening and the costs of treating colorectal cancer.
Whynes, D. K., Walker, A. R., Chamberlain, J. O., Hardcastle, J. D.
The objective of this paper is to compare the hospital costs of treating patients with colorectal cancers detected as a result of a faecal occult blood screening programme with those of patients...
Low survival of South African urban black women with breast cancer.
Walker, A. R., Walker, B. F., Tshabalala, E. N., Isaacson, C., Segal, I.
Case-control study of prostate cancer in black patients in Soweto, South Africa.
Walker, A. R., Walker, B. F., Tsotetsi, N. G., Sebitso, C., Siwedi, D., Walker, A. J.
Faecal pH, dietary fibre intake, and proneness to colon cancer in four South African populations.
Walker, A. R., Walker, B. F., Walker, A. J.
In a series of South African populations, mean faecal pH values were found to be: rural and urban blacks, 6.12 and 6.15; Indians 6.21; coloureds (Eur-African-Malay), 6.29; these are significantly...
The distribution in Kenya of bluetongue virus and antibody, and the Culicoides vector*
Sera from domestic cattle, sheep and goats and 11 wild bovid species taken at 41 locations throughout Kenya were screened for antibody to bluetongue virus using the indirect fluorescent antibody...
A preliminary survey of the epidemiology of bluetongue in Kenya
A survey of the species composition and distribution of the Culicoides midge populations at a range of sites where bluetongue is enzootic isolated a group of dominant species: C. cornutus, C....
Field evidence that roe deer (Capreolus capreolus) are a natural host for Ehrlichia phagocytophila.
Alberdi, M. P., Walker, A. R., Urquhart, K. A.
Samples of blood, spleen and legs from 112 culled roe deer (Capreolus capreolus) were collected from nine sites widespread in the United Kingdom. The prevalence of infection with Ehrlichia...
Genotypic diversity, a survival strategy for the apicomplexan parasite Theileria parva
Katzer, F., Ngugi, D., Walker, A.R., McKeever, D.J.
The tick-borne protozoan parasite Theileria parva causes East Coast fever (ECF), a severe lymphoproliferative disease of cattle that is a major constraint to the improvement of livestock in eastern,...