637 research outputs found
Instances and connectors : issues for a second generation process language
This work is supported by UK EPSRC grants GR/L34433 and GR/L32699Over the past decade a variety of process languages have been defined, used and evaluated. It is now possible to consider second generation languages based on this experience. Rather than develop a second generation wish list this position paper explores two issues: instances and connectors. Instances relate to the relationship between a process model as a description and the, possibly multiple, enacting instances which are created from it. Connectors refers to the issue of concurrency control and achieving a higher level of abstraction in how parts of a model interact. We believe that these issues are key to developing systems which can effectively support business processes, and that they have not received sufficient attention within the process modelling community. Through exploring these issues we also illustrate our approach to designing a second generation process language.Postprin
Climate change and water in the UK – past changes and future prospects
Climate change is expected to modify rainfall, temperature and catchment hydrological responses across the world, and adapting to these water-related changes is a pressing challenge. This paper reviews the impact of anthropogenic climate change on water in the UK and looks at projections of future change. The natural variability of the UK climate makes change hard to detect; only historical increases in air temperature can be attributed to anthropogenic climate forcing, but over the last 50 years more winter rainfall has been falling in intense events. Future changes in rainfall and evapotranspiration could lead to changed flow regimes and impacts on water quality, aquatic ecosystems and water availability. Summer flows may decrease on average, but floods may become larger and more frequent. River and lake water quality may decline as a result of higher water temperatures, lower river flows and increased algal blooms in summer, and because of higher flows in the winter. In communicating this important work, researchers should pay particular attention to explaining confidence and uncertainty clearly. Much of the relevant research is either global or highly localized: decision-makers would benefit from more studies that address water and climate change at a spatial and temporal scale appropriate for the decisions they make
Markers of assimilation of problematic experiences in dementia within the LivDem project
© 2015, © The Author(s) 2015. This study aimed to determine whether the Markers of Assimilation of Problematic Experiences in Dementia scale (MAPED) can be used to identify whether the way in which participants talk about dementia changed during the group. All eight sessions of a LivDem group, which were attended by participants were recorded and transcribed. An initial analysis identified 160 extracts, which were then rated using the MAPED system. Inter-rater reliability was 61% and following a resolution meeting, 35 extracts were discarded, leaving 125 extracts with an agreed marker code. All of the participants were identified as producing a speech marker relating to dementia, and these varied between 0 (warding off) to 6 (problem solution). Examples of these markers are provided. The proportion of emergence markers (indicating the initial stages of assimilation) compared to later markers changed significantly between the first four sessions and the final sessions. This difference was still significant even when the markers produced by the most verbal participant, Graham, were excluded. The use of process measures within psychotherapy complements more conventional outcome measures and has both theoretical and clinical implications
1970s and 'Patient 0' HIV-1 genomes illuminate early HIV/AIDS history in North America.
The emergence of HIV-1 group M subtype B in North American men who have sex with men was a key turning point in the HIV/AIDS pandemic. Phylogenetic studies have suggested cryptic subtype B circulation in the United States (US) throughout the 1970s and an even older presence in the Caribbean. However, these temporal and geographical inferences, based upon partial HIV-1 genomes that postdate the recognition of AIDS in 1981, remain contentious and the earliest movements of the virus within the US are unknown. We serologically screened >2,000 1970s serum samples and developed a highly sensitive approach for recovering viral RNA from degraded archival samples. Here, we report eight coding-complete genomes from US serum samples from 1978-1979-eight of the nine oldest HIV-1 group M genomes to date. This early, full-genome 'snapshot' reveals that the US HIV-1 epidemic exhibited extensive genetic diversity in the 1970s but also provides strong evidence for its emergence from a pre-existing Caribbean epidemic. Bayesian phylogenetic analyses estimate the jump to the US at around 1970 and place the ancestral US virus in New York City with 0.99 posterior probability support, strongly suggesting this was the crucial hub of early US HIV/AIDS diversification. Logistic growth coalescent models reveal epidemic doubling times of 0.86 and 1.12 years for the US and Caribbean, respectively, suggesting rapid early expansion in each location. Comparisons with more recent data reveal many of these insights to be unattainable without archival, full-genome sequences. We also recovered the HIV-1 genome from the individual known as 'Patient 0' (ref. 5) and found neither biological nor historical evidence that he was the primary case in the US or for subtype B as a whole. We discuss the genesis and persistence of this belief in the light of these evolutionary insights.This work was supported by NIH/NIAID R01AI084691 and the David and Lucile Packard Foundation (M.W.); the Wellcome Trust (080651), the University of Oxford’s Clarendon Fund, the Economic and Social Research Council (PTA-026-27-2838), and a J. Armand Bombardier Internationalist Fellowship (R.A.M.); the Research Fund KU Leuven (Onderzoeksfonds KU Leuven, Program Financing no. PF/10/018) and the ‘Fonds voor Wetenschappelijk Onderzoek Vlaanderen’ (FWO) (G066215N) (P.L); and NSF DMS 1264153, NIH R01 HG006139 and NIH R01 AI107034 (M.A.S.).This is the author accepted manuscript. The final version is available from Nature Publishing Group via https://doi.org/10.1038/nature1982
Sex differences in the movement patterns of free-ranging chimpanzees (Pan troglodytes schweinfurthii): foraging and border checking
Most social primates live in cohesive groups, so travel paths inevitably reflect compromise: decision processes of individuals are obscured. The fission-fusion social organisation of the chimpanzee, however, allows an individual’s movements to be investigated independently. We followed 15 chimpanzees (8 male and 7 female) through the relatively flat forest of Budongo, Uganda, plotting the path of each individual over periods of 1-3 days. Chimpanzee movement was parsed into phases ending with halts of more than 20 minutes, during which individuals fed, rested or engaged in social activities. Males, lactating or pregnant females, and sexually receptive females all travelled similar average distances between halts, at similar speeds, and along similarly direct beeline paths. Compared to lactating or pregnant females, males did travel for a significantly longer time each day and halted more often, but the most striking sex differences appeared in the organisation of movement phases into a day’s path. After a halt, males tended to continue in the same direction as before. Lactating or pregnant females showed no such strategy and often retraced the preceding phase, returning to previously visited food patches. We suggest that female chimpanzee movements approximate an optimal solution to feeding requirements, whereas the paths of males allow integration of foraging with territorial defence. The ‘continually moving forwards’ strategy of males enables them to monitor their territory boundaries – border checking – whilst foraging, generally avoiding the explicit boundary patrols observed at other chimpanzee study sites
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Climate change and water in the UK: past changes and future prospects
Climate change is expected to modify rainfall, temperature and catchment hydrological responses across the world, and adapting to these water-related changes is a pressing challenge. This paper reviews the impact of anthropogenic climate change on water in the UK and looks at projections of future change. The natural variability of the UK climate makes change hard to detect; only historical increases in air temperature can be attributed to anthropogenic climate forcing, but over the last 50 years more winter rainfall has been falling in intense events. Future changes in rainfall and evapotranspiration could lead to changed flow regimes and impacts on water quality, aquatic ecosystems and water availability. Summer flows may decrease on average, but floods may become larger and more frequent. River and lake water quality may decline as a result of higher water temperatures, lower river flows and increased algal blooms in summer, and because of higher flows in the winter. In communicating this important work, researchers should pay particular attention to explaining confidence and uncertainty clearly. Much of the relevant research is either global or highly localized: decision-makers would benefit from more studies that address water and climate change at a spatial and temporal scale appropriate for the decisions they mak
COMAP Early Science: II. Pathfinder Instrument
Line intensity mapping (LIM) is a new technique for tracing the global
properties of galaxies over cosmic time. Detection of the very faint signals
from redshifted carbon monoxide (CO), a tracer of star formation, pushes the
limits of what is feasible with a total-power instrument. The CO Mapping
Project (COMAP) Pathfinder is a first-generation instrument aiming to prove the
concept and develop the technology for future experiments, as well as
delivering early science products. With 19 receiver channels in a hexagonal
focal plane arrangement on a 10.4 m antenna, and an instantaneous 26-34 GHz
frequency range with 2 MHz resolution, it is ideally suited to measuring
CO(=1-0) from . In this paper we discuss strategies for designing
and building the Pathfinder and the challenges that were encountered. The
design of the instrument prioritized LIM requirements over those of ancillary
science. After a couple of years of operation, the instrument is well
understood, and the first year of data is already yielding useful science
results. Experience with this Pathfinder will drive the design of the next
generations of experiments.Comment: Paper 2 of 7 in series. 27 pages, 28 figures, submitted to Ap
COMAP Early Science: IV. Power Spectrum Methodology and Results
We present the power spectrum methodology used for the first-season COMAP
analysis, and assess the quality of the current data set. The main results are
derived through the Feed-feed Pseudo-Cross-Spectrum (FPXS) method, which is a
robust estimator with respect to both noise modeling errors and experimental
systematics. We use effective transfer functions to take into account the
effects of instrumental beam smoothing and various filter operations applied
during the low-level data processing. The power spectra estimated in this way
have allowed us to identify a systematic error associated with one of our two
scanning strategies, believed to be due to residual ground or atmospheric
contamination. We omit these data from our analysis and no longer use this
scanning technique for observations. We present the power spectra from our
first season of observing and demonstrate that the uncertainties are
integrating as expected for uncorrelated noise, with any residual systematics
suppressed to a level below the noise. Using the FPXS method, and combining
data on scales we estimate , the first direct 3D
constraint on the clustering component of the CO(1-0) power spectrum in the
literature.Comment: Paper 4 of 7 in series. 18 pages, 11 figures, as accepted in Ap
COMAP Early Science: VI. A First Look at the COMAP Galactic Plane Survey
We present early results from the COMAP Galactic Plane Survey conducted
between June 2019 and April 2021, spanning in Galactic
longitude and |b|<1.\!\!^{\circ}5 in Galactic latitude with an angular
resolution of . The full survey will span -
and will be the first large-scale radio continuum survey at
GHz with sub-degree resolution. We present initial results from the first part
of the survey, including diffuse emission and spectral energy distributions
(SEDs) of HII regions and supernova remnants. Using low and high frequency
surveys to constrain free-free and thermal dust emission contributions, we find
evidence of excess flux density at GHz in six regions that we interpret
as anomalous microwave emission. Furthermore we model UCHII contributions using
data from the GHz CORNISH catalogue and reject this as the cause of the
GHz excess. Six known supernova remnants (SNR) are detected at GHz,
and we measure spectral indices consistent with the literature or show evidence
of steepening. The flux density of the SNR W44 at GHz is consistent with
a power-law extrapolation from lower frequencies with no indication of spectral
steepening in contrast with recent results from the Sardinia Radio Telescope.
We also extract five hydrogen radio recombination lines to map the warm ionized
gas, which can be used to estimate electron temperatures or to constrain
continuum free-free emission. The full COMAP Galactic plane survey, to be
released in 2023/2024, will be an invaluable resource for Galactic
astrophysics.Comment: Paper 6 of 7 in series. 28 pages, 10 figures, submitted to Ap
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