158 research outputs found
A game of two halves: Looking for evidence for both embedded and direct procurement in a simulated dataset
The concepts of embedded and direct procurement have become weighted with extra baggage over the years. In embedded procurement, lithics are obtained along with other resources, while direct procurement involves a deliberate trip to the source for the sole purpose of obtaining that raw material. Lewis Binford suggested that direct procurement means something went wrong (a sign of poor planning), and that embedded procurement is the norm. Other authors found valid reasons why direct procurement could be deliberate, planned, and beneficial. Regardless, the two have often been seen as diametrically opposed, and applied to interpretations of mobility and lithic procurement as if they are mutually exclusive of one another. They have also been variously conflated with expedient and curated technology, the use of local vs. exotic raw materials, and so on. The often site-centric vision of archaeologists (we find it hard to see that people may have been passing through a site, not based there and going out and coming back), can further confuse the issue. The most important problem, however, is: how can we tell the difference between embedded and direct procurement from the stone tools collected at an archaeological site? We created the scenario of a site with various proportions of stone tools from different sources. In order to not influence the site characteristics through a priori expectations, we randomly assigned source qualities and percentages in the assemblage, along with the distances and directions of each source relative to the site. Then each author analysed those data from one of two points of view: LW convinced in advance that the evidence supported embedded lithic procurement, and PM equally certain that a direct strategy was apparent. In both cases, the authors felt they had sufficient “justification” to bolster their point of view and build a strong case for their raw material procurement strategy. This exercise gave some insight into the usefulness and limitations of these two concepts as heuristic devices, as they continue to be a major influence on anyone trying to interpret lithic procurement
Uncertainty in Signals of Large-Scale Climate Variations in Radiosonde and Satellite Upper-Air Temperature Datasets
There is no single reference dataset of long-term global upper-air temperature observations, although several
groups have developed datasets from radiosonde and satellite observations for climate-monitoring purposes. The
existence of multiple data products allows for exploration of the uncertainty in signals of climate variations and
change. This paper examines eight upper-air temperature datasets and quantifies the magnitude and uncertainty
of various climate signals, including stratospheric quasi-biennial oscillation (QBO) and tropospheric ENSO
signals, stratospheric warming following three major volcanic eruptions, the abrupt tropospheric warming of
1976–77, and multidecadal temperature trends. Uncertainty estimates are based both on the spread of signal
estimates from the different observational datasets and on the inherent statistical uncertainties of the signal in
any individual dataset.
The large spread among trend estimates suggests that using multiple datasets to characterize large-scale upperair
temperature trends gives a more complete characterization of their uncertainty than reliance on a single
dataset. For other climate signals, there is value in using more than one dataset, because signal strengths vary.
However, the purely statistical uncertainty of the signal in individual datasets is large enough to effectively
encompass the spread among datasets. This result supports the notion of an 11th climate-monitoring principle,
augmenting the 10 principles that have now been generally accepted (although not generally implemented) by
the climate community. This 11th principle calls for monitoring key climate variables with multiple, independent
observing systems for measuring the variable, and multiple, independent groups analyzing the data
Tuberculosis Microepidemics among Dispersed Migrants, Birmingham, UK, 2004-2013
MIRU-VNTR typing was supported by the Public Health England
National TB Strain Typing Project. M.M. is funded by the
UK Clinical Research Collaboration Modernising Medical Microbiology
Consortium. C.B. is funded by the Heart of Birmingham
Primary Care Trust and Public Health England
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Mainstreaming domestic and gender-based violence into sociology and the criminology of violence
Sociological and criminological views of domestic and gender-based violencegenerally either dismiss it as not worthy of consideration, or focus on specificgroups of offenders and victims (male youth gangs, partner violence victims). Inthis paper, we take a holistic approach to violence, extending the definition fromthat commonly in use to encompass domestic violence and sexual violence. Weoperationalize that definition by using data from the latest sweep of the CrimeSurvey for England and Wales. By so doing, we identify that violence is currentlyunder-measured and ubiquitous; that it is gendered, and that other forms of violence (family violence, acquaintance violence against women) are equally ofconcern. We argue that violence studies are an important form of activity forsociologists
Linking micellar structures to hydrogelation for salt-triggered dipeptide gelators
Some functionalised dipeptides can form hydrogels when salts are added to solutions at high pH. We have used surface tension, conductivity, rheology, optical, confocal and scanning electron microscopy, 1H NMR and UV-Vis spectroscopy measurements to characterise fully the phase behaviour of solutions of one specific gelator, 2NapFF, at 25 °C at pH 10.5. We show that this specific naphthalene–dipeptide undergoes structural transformations as the concentration is increased, initially forming spherical micelles, then worm-like micelles, followed by association of these worm-like micelles. On addition of a calcium salt, gels are generally formed as long as worm-like micelles are initially present in solution, although there are structural re-organisations that occur at lower concentrations, allowing gelation at lower than expected concentration. Using IR and SANS, we show the differences between the structures present in the solution and hydrogel phases
The state of the Martian climate
60°N was +2.0°C, relative to the 1981–2010 average value (Fig. 5.1). This marks a new high for the record. The average annual surface air temperature (SAT) anomaly for 2016 for land stations north of starting in 1900, and is a significant increase over the previous highest value of +1.2°C, which was observed in 2007, 2011, and 2015. Average global annual temperatures also showed record values in 2015 and 2016. Currently, the Arctic is warming at more than twice the rate of lower latitudes
A quantification of uncertainties in historical tropical tropospheric temperature trends from radiosondes
The consistency of tropical tropospheric temperature trends with climate model
expectations remains contentious. A key limitation is that the uncertainties in observations
from radiosondes are both substantial and poorly constrained. We present a thorough
uncertainty analysis of radiosonde‐based temperature records. This uses an automated
homogenization procedure and a previously developed set of complex error models where
the answer is known a priori. We perform a number of homogenization experiments in
which error models are used to provide uncertainty estimates of real‐world trends. These
estimates are relatively insensitive to a variety of processing choices. Over 1979–2003, the
satellite‐equivalent tropical lower tropospheric temperature trend has likely (5–95%
confidence range) been between −0.01 K/decade and 0.19 K/decade (0.05–0.23 K/decade
over 1958–2003) with a best estimate of 0.08 K/decade (0.14 K/decade). This range
includes both available satellite data sets and estimates from models (based upon scaling
their tropical amplification behavior by observed surface trends). On an individual
pressure level basis, agreement between models, theory, and observations within the
troposphere is uncertain over 1979 to 2003 and nonexistent above 300 hPa. Analysis of
1958–2003, however, shows consistent model‐data agreement in tropical lapse rate
trends at all levels up to the tropical tropopause, so the disagreement in the more recent
period is not necessarily evidence of a general problem in simulating long‐term global
warming. Other possible reasons for the discrepancy since 1979 are: observational errors
beyond those accounted for here, end‐point effects, inadequate decadal variability in model
lapse rates, or neglected climate forcings
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Evidence for changes in stratospheric transport and mixing over the past three decades based on multiple data sets and tropical leaky pipe analysis
Variability in the strength of the stratospheric Lagrangian mean meridional or Brewer-Dobson circulation and horizontal mixing into the tropics over the past three decades are examined using observations of stratospheric mean age of air and ozone. We use a simple representation of the stratosphere, the tropical leaky pipe (TLP) model, guided by mean meridional circulation and horizontal mixing changes in several reanalyses data sets and chemistry climate model (CCM) simulations, to help elucidate reasons for the observed changes in stratospheric mean age and ozone. We find that the TLP model is able to accurately simulate multiyear variability in ozone following recent major volcanic eruptions and the early 2000s sea surface temperature changes, as well as the lasting impact on mean age of relatively short-term circulation perturbations. We also find that the best quantitative agreement with the observed mean age and ozone trends over the past three decades is found assuming a small strengthening of the mean circulation in the lower stratosphere, a moderate weakening of the mean circulation in the middle and upper stratosphere, and a moderate increase in the horizontal mixing into the tropics. The mean age trends are strongly sensitive to trends in the horizontal mixing into the tropics, and the uncertainty in the mixing trends causes uncertainty in the mean circulation trends. Comparisons of the mean circulation and mixing changes suggested by the measurements with those from a recent suite of CCM runs reveal significant differences that may have important implications on the accurate simulation of future stratospheric climate
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