21,697 research outputs found
Coastal hunter-gatherers and social evolution: marginal or central?
General accounts of global trends in world prehistory are dominated by narratives of conquest on land: scavenging and hunting of land mammals, migration over land bridges and colonisation of new continents, gathering of plants, domestication, cultivation, and ultimately sustained population growth founded on agricultural surplus. Marine and aquatic resources fit uneasily into this sequence of social and economic development, and societies strongly dependent on them have often been regarded as relatively late in the sequence, geographically marginal or anomalous. We consider the biases and preconceptions of the ethnographic and archaeological records that have contributed to this view of marginality and examine some current issues focusing on the role of marine resources at the Mesolithic-Neolithic transition of northwest Europe. We suggest that pre-existing conventions should be critically re-examined, that coastlines may have played a more significant, widespread and persistent role as zones of attraction for human dispersal, population growth and social interaction than is commonly recognised, and that this has been obscured by hunter-gatherer and farmer stereotypes of prehistoric economies
Apollo 12 Voice Transcript Pertaining to the Geology of the Landing Site, Volume 2
An edited record of the conversions between the Apollo 12 astronauts and mission control pertaining to the geology of the landing site, is presented. All discussions and observations documenting the lunar landscape, its geologic characteristics, the rocks and soils collected and the lunar surface photographic record are included along with supplementary remarks essential to the continuity of events during the mission
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Influence of surgery and rehabilitation conditioning on psychophysiological fitness
The purpose of this study was to assess changes in psychophysiological fitness following reconstructive knee surgery and early phase (2.5 months) physical rehabilitation. Nine patients (7 male, 2 female; mean age, 29.9 years) electing to undergo anterior cruciate ligament reconstructive surgery (central third, bone-patella tendon-bone graft) were assessed on four separate assessment occasions post-surgery. Repeated measures ANOVAs showed significant condition (injured/non-injured leg) by test occasion (2 weeks pre-surgery and 6, 8 and 10 weeks post-surgery) interactions for knee ligamentous compliance (anterior tibiofemoral displacement), peak force and electromechanical delay associated with the knee flexors of the injured and noninjured legs (F3,24 = 4.7 to 6.6; p < 0.01), together with individualized emotional profile disturbance scores that were significantly less at 10 weeks post-surgery compared to pre-surgery, 6 weeks and 8 weeks post-surgery (F3,24 = 7.6; p < 0.01). Spearman rank correlation coefficients identified significant relationships between musculoskeletal fitness and emotional profile scores at pre-surgery (r = 0.69–0.72; p < 0.05) and at 8 weeks post-surgery (r = 0.70–0.73; p < 0.05). The 6 Bi-POMS subscales and the 12 ERAIQ responses found inconsistent patterns of response and relationships across the assessment occasions. Overall, the patterning of changes and associations amongst emotional performance profile discrepancy scores in conjunction with those scores from indices of musculoskeletal fitness performance capability offered important support for the efficacy of an approach which integrates self-perceptive and objective measurements of fitness capability during rehabilitation following surgery to a synovial joint
Analysis and application of digital spectral warping in analog and mixed-signal testing
Spectral warping is a digital signal processing transform which shifts the frequencies contained within a signal along the frequency axis. The Fourier transform coefficients of a warped signal correspond to frequency-domain 'samples' of the original signal which are unevenly spaced along the frequency axis. This property allows the technique to be efficiently used for DSP-based analog and mixed-signal testing. The analysis and application of spectral warping for test signal generation, response analysis, filter design, frequency response evaluation, etc. are discussed in this paper along with examples of the software and hardware implementation
Invasion threshold in heterogeneous metapopulation networks
We study the dynamics of epidemic and reaction-diffusion processes in
metapopulation models with heterogeneous connectivity pattern. In SIR-like
processes, along with the standard local epidemic threshold, the system
exhibits a global invasion threshold. We provide an explicit expression of the
threshold that sets a critical value of the diffusion/mobility rate below which
the epidemic is not able to spread to a macroscopic fraction of subpopulations.
The invasion threshold is found to be affected by the topological fluctuations
of the metapopulation network. The presented results provide a general
framework for the understanding of the effect of travel restrictions in
epidemic containment.Comment: 4 pages, 2 figure
Generalized MICZ-Kepler Problems and Unitary Highest Weight Modules
For each integer , we demonstrate that a -dimensional
generalized MICZ-Kepler problem has an \mr{Spin}(2, 2n+2) dynamical symmetry
which extends the manifest \mr{Spin}(2n+1) symmetry. The Hilbert space of
bound states is shown to form a unitary highest weight \mr{Spin}(2,
2n+2)-module which occurs at the first reduction point in the
Enright-Howe-Wallach classification diagram for the unitary highest weight
modules. As a byproduct, we get a simple geometric realization for such a
unitary highest weight \mr{Spin}(2, 2n+2)-module.Comment: 27 pages, Refs. update
A Mesolithic settlement site at Howick, Northumberland: a preliminary report
Excavations at a coastal site at Howick during 2000 and 2002 have revealed evidence for a substantial Mesolithic settlement and a Bronze Age cist cemetery. Twenty one radiocarbon determinations of the earlier eighth millennium BP (Cal.) indicate that the Mesolithic site is one of the earliest known in northern Britain. An 8m core of sediment was recovered from stream deposits adjacent to the archaeological site which provides information on local environmental conditions. Howick offers a unique opportunity to understand aspects of hunter-gatherer colonisation and settlement during a period of rapid palaeogeographical change around the margins of the North Sea basin, at a time when it was being progressively inundated by the final stages of the postglacial marine transgression. The cist cemetery will add to the picture of Bronze Age occupation of the coastal strip and again reveals a correlation between the location of Bronze Age and Mesolithic sites which has been observed elsewhere in the region
Exponent of Cross-sectional Dependence: Estimation and Inference
An important issue in the analysis of cross-sectional dependence which has received renewed interest in the past few years is the need for a better understanding of the extent and nature of such cross dependencies. In this paper we focus on measures of cross-sectional dependence and how such measures are related to the behaviour of the aggregates defined as cross-sectional averages. We endeavour to determine the rate at which the cross-sectional weighted average of a set of variables appropriately demeaned, tends to zero. One parameterisation sets this to be , for . Given the fashion in which it arises, we refer to as the exponent of cross-sectional dependence. We derive an estimator of from the estimated variance of the cross-sectional average of the variables under consideration. We propose bias corrected estimators, derive their asymptotic properties and consider a number of extensions. We include a detailed Monte Carlo study supporting the theoretical results. Finally, we undertake an empirical investigation of using the S&P 500 data-set, and a large number of macroeconomic variables across and within countries
-Trinomial identities
We obtain connection coefficients between -binomial and -trinomial
coefficients. Using these, one can transform -binomial identities into a
-trinomial identities and back again. To demonstrate the usefulness of this
procedure we rederive some known trinomial identities related to partition
theory and prove many of the conjectures of Berkovich, McCoy and Pearce, which
have recently arisen in their study of the and
perturbations of minimal conformal field theory.Comment: 21 pages, AMSLate
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