1,007 research outputs found
Comparisons between geographies of mortality and deprivation from the 1900s and 2001: spatial analysis of census and mortality statistics
Objectives To examine the geographical relation between mortality and deprivation in England and Wales at the start of the 20th and 21st centuries. To explore the evidence for a strengthening or weakening of this relation over the century and test for relations between the mortality and deprivation patterns of a century ago and modern mortality and causes of death
A historical GIS for England and Wales: a framework for reconstructing past geographies and analysing long-term change
PhDThis thesis describes the creation and possible uses of a Geographical Information
System that contains the changing boundaries of the major administrative units of
England and Wales from 1840 to 1974. For over 150 years the census, the General
Register Office, and others have used these units to publish a wealth of data
concerning the population of the country. The key issue addressed by the thesis is that
changes in the administrative geography have hampered much research on long-term
change in society that could have been done using these sources. The goal of the
thesis is the creation of framework to allow the analysis of long-term socio-economic
change that makes maximum use of the available data.
This involves not only making use of the data's attribute (statistical) component,
but also their spatial and temporal components. In order to do this, the thesis provides
solutions to two key problems: the first is how to build a GIS containing
administrative units that incorporates an accurate record of their changing boundaries
and can be linked to statistical data in a flexible manner. The second is how to remove
the impact of boundary changes when comparing datasets published at different dates.
This is done by devising a methodology for interpolating data from the administrative
units they were published using, onto a single target geography. An evaluation of the
accuracy of this interpolation is performed and examples are given of how this type of
research could be conducted. Taken together, these will release information locked up
within historical socio-economic statistics by allowing space to be explicitly
incorporated into any explorations of the data. This, in turn, allows research to explore
the past with increased levels of both spatial and attribute data for longer time periods
Discovery of Four High Proper Motion L Dwarfs, Including a 10 pc L Dwarf at the L/T Transition
We discover four high proper motion L dwarfs by comparing the Wide-field
Infrared Survey Explorer (WISE) to the Two Micron All Sky Survey (2MASS). WISE
J140533.32+835030.5 is an L dwarf at the L/T transition with a proper motion of
0.85+/-0.02" yr^-1, previously overlooked due to its proximity to a bright star
(V=12 mag). From optical spectroscopy we find a spectral type of L8, and from
moderate-resolution J band spectroscopy we find a near-infrared spectral type
of L9. We find WISE J140533.32+835030.5 to have a distance of 9.7+/-1.7 pc,
bringing the number of L dwarfs at the L/T transition within 10 pc from six to
seven. WISE J040137.21+284951.7, WISE J040418.01+412735.6, and WISE
J062442.37+662625.6 are all early L dwarfs within 25 pc, and were classified
using optical and low-resolution near-infrared spectra. WISE
J040418.01+412735.6 is an L2 pec (red) dwarf, a member of the class of
unusually red L dwarfs. We use follow-up optical and low-resolution
near-infrared spectroscopy to classify a previously discovered (Castro & Gizis
2012) fifth object WISEP J060738.65+242953.4 as an (L8 Opt/L9 NIR), confirming
it as an L dwarf at the L/T transition within 10 pc. WISEP J060738.65+242953.4
shows tentative CH_4 in the H band, possibly the result of unresolved binarity
with an early T dwarf, a scenario not supported by binary spectral template
fitting. If WISEP J060738.65+242953.4 is a single object, it represents the
earliest onset of CH_4 in the H band of an L/T transition dwarf in the SpeX
Library. As very late L dwarfs within 10 pc, WISE J140533.32+835030.5 and WISEP
J060738.65+242953.4 will play a vital role in resolving outstanding issues at
the L/T transition.Comment: 45 pages, 12 figures, accepted for publication in Ap
Surface Gravities for 228 M, L, and T Dwarfs in the NIRSPEC Brown Dwarf Spectroscopic Survey
We combine 131 new medium-resolution (R~2000) J-band spectra of M, L, and T
dwarfs from the Keck NIRSPEC Brown Dwarf Spectroscopic Survey (BDSS) with 97
previously published BDSS spectra to study surface-gravity-sensitive indices
for 228 low-mass stars and brown dwarfs spanning spectral types M5-T9.
Specifically, we use an established set of spectral indices to determine
surface gravity classifications for all M6-L7 objects in our sample by
measuring equivalent widths (EW) of the K I lines at 1.1692, 1.1778, 1.2529 um,
and the 1.2 um FeHJ absorption index. Our results are consistent with previous
surface gravity measurements, showing a distinct double peak - at ~L5 and T5 -
in K I EW as a function of spectral type. We analyze K I EWs of 73 objects of
known ages and find a linear trend between log(Age) and EW. From this
relationship, we assign age ranges to the very low gravity, intermediate
gravity, and field gravity designations for spectral types M6-L0.
Interestingly, the ages probed by these designations remain broad, change with
spectral type, and depend on the gravity sensitive index used. Gravity
designations are useful indicators of the possibility of youth, but current
datasets cannot be used to provide a precise age estimate.Comment: 33 pages, 13 figures, ApJ in pres
Drosophila tan Encodes a Novel Hydrolase Required in Pigmentation and Vision
Many proteins are used repeatedly in development, but usually the function of the protein is similar in the different contexts. Here we report that the classical Drosophila melanogaster locus tan encodes a novel enzyme required for two very different cellular functions: hydrolysis of N-β-alanyl dopamine (NBAD) to dopamine during cuticular melanization, and hydrolysis of carcinine to histamine in the metabolism of photoreceptor neurotransmitter. We characterized two tan-like P-element insertions that failed to complement classical tan mutations. Both are inserted in the 5′ untranslated region of the previously uncharacterized gene CG12120, a putative homolog of fungal isopenicillin-N N-acyltransferase (EC 2.3.1.164). Both P insertions showed abnormally low transcription of the CG12120 mRNA. Ectopic CG12120 expression rescued tan mutant pigmentation phenotypes and caused the production of striking black melanin patterns. Electroretinogram and head histamine assays indicated that CG12120 is required for hydrolysis of carcinine to histamine, which is required for histaminergic neurotransmission. Recombinant CG12120 protein efficiently hydrolyzed both NBAD to dopamine and carcinine to histamine. We conclude that D. melanogaster CG12120 corresponds to tan. This is, to our knowledge, the first molecular genetic characterization of NBAD hydrolase and carcinine hydrolase activity in any organism and is central to the understanding of pigmentation and photoreceptor function
The Exemplar T8 Subdwarf Companion of Wolf 1130
We have discovered a wide separation (188.5") T8 subdwarf companion to the
sdM1.5+WD binary Wolf 1130. Companionship of WISE J200520.38+542433.9 is
verified through common proper motion over a ~3 year baseline. Wolf 1130 is
located 15.83 +/- 0.96 parsecs from the Sun, placing the brown dwarf at a
projected separation of ~3000 AU. Near-infrared colors and medium resolution
(R~2000-4000) spectroscopy establish the uniqueness of this system as a
high-gravity, low-metallicity benchmark. Although there are a number of
low-metallicity T dwarfs in the literature, WISE J200520.38+542433.9 has the
most extreme inferred metallicity to date with [Fe/H] = -0.64 +/- 0.17 based on
Wolf 1130. Model comparisons to this exemplar late-type subdwarf support it
having an old age, a low metallicity, and a small radius. However, the
spectroscopic peculiarities of WISE J200520.38+542433.9 underscore the
importance of developing the low-metallicity parameter space of the most
current atmospheric models.Comment: Accepted to ApJ on 05 September 2013; 33 pages in preprint format, 8
figures, 3 table
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