The stellar populations of early-type galaxies in groups and clusters

This thesis investigates the relationship between the environment of an early-type galaxy and its stellar populations. Most importantly, we wish to determine whether the star formation histories of early-type galaxies depend on the density of the group or cluster to which they belong. This issue is of considerable consequence, as it provides a means to distinguish whether the early-type morphology of these systems is determined at their formation, or whether it is assumed at a later time due to the action of their changing surroundings. We have applied two methods to compare the stellar populations of these galaxies. Firstly, we have analysed the strengths of surface gravity sensitive spectral lines in order to compare the relative contributions of dwarf and giant stars to the blue light. Several samples of E and SO galaxies, drawn from a wide variety of environments, have been measured with this technique. Secondly, we have made a precise comparison of the broad-band colours of early-type galaxies in the Coma and Virgo clusters. These clusters have very different average densities, and distinctly disparate mixtures of galaxy morphological types. The findings of these studies appear to be contradictory, however. Although the surface gravity analysis indicates that early-type galaxies in lower density regions contain more substantial populations of relatively young stars, the broad-band colours of galaxies in the Virgo and Coma clusters are indistinguishable. A third section of the thesis develops the Press-Schechter theory for the evolution of gravitational structure in an expanding universe. Our work allows us to compare the past histories of the environments of galaxies as a function of the mass of the group or cluster to which they presently belong. In the final chapter, we discuss how the results from these three areas of research relate to each other, and suggest two ways in which the apparent paradox of our observational work may be resolved. Considering the implications of our theoretical work leads us to review the fundamental differences between the 'nature' and 'nurture' scenarios for the origin of galaxy morphology.- ii

OncoLog Volume 49, Number 01, January 2004

Pregnancy and Cancer Treatment Often Are Not Mutually Exclusive Studies of the Viral Origins of Some Cancers Lead to New Prevention, Treatment Strategies House Call: Cancer and Your Weight DiaLog: Treating Breast Cancer during Pregnancy, by Karin M.E.H. Gwyn, MD, Assistant Professor, and Richard L. Theriault, DO, Professor, Department of Breast Medical Oncologyhttps://openworks.mdanderson.org/oncolog/1125/thumbnail.jp

The Next Generation Virgo Cluster Survey. XII. Stellar Populations and Kinematics of Compact, Low-Mass Early-Type Galaxies from Gemini GMOS-IFU Spectroscopy

We present Gemini GMOS-IFU data of eight compact low-mass early-type galaxies (ETGs) in the Virgo cluster. We analyse their stellar kinematics, stellar population, and present two-dimensional maps of these properties covering the central 5"x 7" region. We find a large variety of kinematics: from non- to highly-rotating objects, often associated with underlying disky isophotes revealed by deep images from the Next Generation Virgo Cluster Survey. In half of our objects, we find a centrally-concentrated younger and more metal-rich stellar population. We analyze the specific stellar angular momentum through the lambdaR parameter and find six fast-rotators and two slow-rotators, one having a thin counter-rotating disk. We compare the local galaxy density and stellar populations of our objects with those of 39 more extended low-mass Virgo ETGs from the SMAKCED survey and 260 massive ($M>10^{10}$\Msun) ETGs from the A3D sample. The compact low-mass ETGs in our sample are located in high density regions, often close to a massive galaxy and have, on average, older and more metal-rich stellar populations than less compact low-mass galaxies. We find that the stellar population parameters follow lines of constant velocity dispersion in the mass-size plane, smoothly extending the comparable trends found for massive ETGs. Our study supports a scenario where low-mass compact ETGs have experienced long-lived interactions with their environment, including ram-pressure stripping and gravitational tidal forces, that may be responsible for their compact nature.Comment: Accepted in ApJ, 19 pages, 10 figure

The splitting of double-component active asteroid P/2016 J1 (PANSTARRS)

We present deep imaging observations, orbital dynamics, and dust tail model analyses of the double-component asteroid P/2016 J1 (J1-A and J1-B). The observations were acquired at the Gran Telescopio Canarias (GTC) and the Canada-France-Hawaii Telescope (CFHT) from mid March to late July, 2016. A statistical analysis of backward-in-time integrations of the orbits of a large sample of clone objects of P/2016 J1-A and J1-B shows that the minimum separation between them occurred most likely $\sim$2300 days prior to the current perihelion passage, i.e., during the previous orbit near perihelion. This closest approach was probably linked to a fragmentation event of their parent body. Monte Carlo dust tail models show that those two components became active simultaneously $\sim$250 days before the current perihelion, with comparable maximum loss rates of $\sim$0.7 kg s$^{-1}$ and $\sim$0.5 kg s$^{-1}$, and total ejected masses of 8$\times$10$^{6}$ kg and 6$\times$10$^{6}$ kg for fragments J1-A and J1-B, respectively. In consequence, the fragmentation event and the present dust activity are unrelated. The simultaneous activation times of the two components and the fact that the activity lasted 6 to 9 months or longer, strongly indicate ice sublimation as the most likely mechanism involved in the dust emission process.Comment: Accepted by ApJ Letters, Feb. 17, 201

On the Continuous Formation of Field Spheroidal Galaxies in Hierarchical Models of Structure Formation

We re-examine the assembly history of field spheroidals as a potentially powerful discriminant of galaxy formation models. Whereas monolithic collapse and hierarchical, merger-driven, models suggest radically different histories for these galaxies, neither the theoretical predictions nor the observational data for field galaxies have been sufficiently reliable for precise conclusions to be drawn. A major difficulty in interpreting the observations, reviewed here, concerns the taxonomic definition of spheroidals in merger-based models. Using quantitative measures of recent star formation activity drawn from the internal properties of a sample of distant field galaxies in the Hubble Deep Fields, we undertake a new analysis to assess the continuous formation of spheroidal galaxies. Whereas abundances and redshift distributions of modelled spheroidals are fairly insensitive to their formation path, we demonstrate that the distribution and amount of blue light arising from recent mergers provides a more sensitive approach. With the limited resolved data currently available, the rate of mass assembly implied by the observed colour inhomogeneities is compared to that expected in popular Lambda-dominated cold dark matter models of structure formation. These models produce as many highly inhomogeneous spheroidals as observed, but underpredict the proportion of homogeneous, passive objects. We conclude that colour inhomogeneities, particularly when combined with spectroscopic diagnostics for large, representative samples of field spheroidals, will be a more valuable test of their physical assembly history than basic source counts and redshift distributions. Securing such data should be a high priority for the Advanced Camera for Surveys on Hubble Space Telescope.Comment: 14 pages, 7 figures, submitted to MNRA

A ‘wiring diagram’ for source strength traits impacting wheat yield potential

Source traits are currently of great interest for the enhancement of yield potential; for example, much effort is being expended to find ways of modifying photosynthesis. However, photosynthesis is but one component of crop regulation, so sink activities and the coordination of diverse processes throughout the crop must be considered in an integrated, systems approach. A set of ‘wiring diagrams’ has been devised as a visual tool to integrate the interactions of component processes at different stages of wheat development. They enable the roles of chloroplast, leaf, and whole-canopy processes to be seen in the context of sink development and crop growth as a whole. In this review, we dissect source traits both anatomically (foliar and non-foliar) and temporally (pre- and post-anthesis), and consider the evidence for their regulation at local and whole-plant/crop levels. We consider how the formation of a canopy creates challenges (self-occlusion) and opportunities (dynamic photosynthesis) for components of photosynthesis. Lastly, we discuss the regulation of source activity by feedback regulation. The review is written in the framework of the wiring diagrams which, as integrated descriptors of traits underpinning grain yield, are designed to provide a potential workspace for breeders and other crop scientists that, along with high-throughput and precision phenotyping data, genetics, and bioinformatics, will help build future dynamic models of trait and gene interactions to achieve yield gains in wheat and other field crops.Research of the authors on physiology and genetics of wheat yield potential has been funded by many different sources over the years. Recent grants include the International Wheat Yield Partnership (IWYP) projects funded by the Biotechnology and Biological Research Council of the UK [BB/N021061/1, BB/ N020871/2, BB/S005072/1] (IWYP48, IWYP64, IWYP163 and IWYP25FP, respectively), as well as projects funded by other donors (State Research Agency of Spain: AGL2015-69595-R and RTI2018-096213-B-100)

Kuiper Belt Occultation Predictions

Here we present observations of seven large Kuiper Belt objects. From these observations, we extract a point source catalog with ∼0.01″ precision, and astrometry of our target Kuiper Belt objects with 0.04–0.08″ precision within that catalog. We have developed a new technique to predict the future occurrence of stellar occultations by Kuiper Belt objects. The technique makes use of a maximum likelihood approach which determines the best-fit adjustment to cataloged orbital elements of an object. Using simulations of a theoretical object, we discuss the merits and weaknesses of this technique compared to the commonly adopted ephemeris offset approach. We demonstrate that both methods suffer from separate weaknesses, and thus together provide a fair assessment of the true uncertainty in a particular prediction. We present occultation predictions made by both methods for the seven tracked objects, with dates as late as 2015. Finally, we discuss observations of three separate close passages of Quaoar to field stars, which reveal the accuracy of the element adjustment approach, and which also demonstrate the necessity of considering the uncertainty in stellar position when assessing potential occultations

Prospectus, May 7, 1981

SPEECH TEAM 11TH RANKED; National Forensics Top 20; C of C V-P, Neils predicts downtown area will change; Overcast and Snyder receive award; Co-Editors named for 1981-82; Barnes looks back on his Parkland experiences; Letters to the Editor: Student criticizes review; Classifieds; Our mistake! Stugo candidate got platform in on time; Convocations Wants You!!; Now is the time to get married; More letters to the Editor: New Stugo senator, Jackson appreciates support; Schumacher\u27s final notes...; Trail, Hillary win in close Stugo election last week; Trail expresses gratitude for the voters; Be kind to animals ; Japan King of bicycle road; Motocross bikes good for kids; Rogers, Gayle at Assembly Hall May 13.; Off Broadway: Dynamic, Aggressive; Gayle not living under Lorett\u27s shadow now!; Piloting not as easy as you may think!; Drug problem is going to get worse. ; Art Thesis Exhibit disappointing; Latin may be on its way back; Parkland secretaries enjoy the good life; Model Rockets popular; RWS\u27S help each other; PC offers one-day driving course; Ramblin\u27: Alender\u27s rambles are over; Rundgren just changing with the times; Do you want hard rock...?; Frazier, Turpin part of Senior May Fest; Here\u27s the 1981 Prospectus staff; CIRS has the info on day care; Did You Know That...Some Superstitions; \u27Recent rains still not enough\u27: Burwash; Barkstall appalled by Atlanta slayings: Urban League director says blacks are still discriminated against; Are we running out of natural resources?; Get out your horses for PC\u27s Horse Show; Parkland Happenings: Spring concerts feature Irving Berlin; Awards Banquet a success!; Winning Intellectual Freedom Essay; A child\u27s world is important throughout all stages; Dental classes named for \u2781-82; Final Examinations -- Spring, 1981; Cobras bow to Lake Land; Patrick to Tennessee; Softball team beats Danville; ...beat Lincoln Land three; Letter to the Sports Editor: Student upset; Walder wins final Fast Freddy; scoreboard; Baseballhttps://spark.parkland.edu/prospectus_1981/1017/thumbnail.jp

Going for GOLD! Greater Manchester Growing Older with Learning Disabilities: An inclusive research project to reduce social isolation amongst older adults with learning disabilities

This research was part of the Greater Manchester Growing Older with Learning Disabilities (GM GOLD) project, which was carried out by a team of 16 older people with learning disabilities. The aim was to reduce social isolation amongst older adults (aged 50+) with learning disabilities and to find out what makes somewhere an age-friendly place to live for older adults with learning disabilities. The team was supported by 'research buddies' from Manchester Metropolitan University and the partner organisations to conduct interviews and focus groups with 59 older people (aged 50-79 years) with learning disabilities from eight Greater Manchester areas (Bolton, Bury, Manchester, Oldham, Rochdale, Salford, Tameside, Wigan). Later life transitions for people with learning disabilities are particularly disruptive, and they are at particular risk of social isolation and loneliness. People with learning disabilities have the same rights to relationships and to participate in the cultural life of the community as the rest of society. If society, neighbourhoods and communities do not become more inclusive of people with learning disabilities, in addition to the legal, moral and ethical implications, this is likely to result in additional demand for public services