Shared intentions and the advance of cumulative culture in hunter-gatherers

It has been hypothesized that the evolution of modern human cognition was catalyzed by the development of jointly intentional modes of behaviour. From an early age (1-2 years), human infants outperform apes at tasks that involve collaborative activity. Specifically, human infants excel at joint action motivated by reasoning of the form "we will do X" (shared intentions), as opposed to reasoning of the form "I will do X [because he is doing X]" (individual intentions). The mechanism behind the evolution of shared intentionality is unknown. Here we formally model the evolution of jointly intentional action and show under what conditions it is likely to have emerged in humans. Modelling the interaction of hunter-gatherers as a coordination game, we find that when the benefits from adopting new technologies or norms are low but positive, the sharing of intentions does not evolve, despite being a mutualistic behaviour that directly benefits all participants. When the benefits from adopting new technologies or norms are high, such as may be the case during a period of rapid environmental change, shared intentionality evolves and rapidly becomes dominant in the population. Our results shed new light on the evolution of collaborative behaviours.Comment: 6 pages, 4 figures, 1 table, Supplementary Information not include

Direct detection of electron backscatter diffraction patterns.

We report the first use of direct detection for recording electron backscatter diffraction patterns. We demonstrate the following advantages of direct detection: the resolution in the patterns is such that higher order features are visible; patterns can be recorded at beam energies below those at which conventional detectors usefully operate; high precision in cross-correlation based pattern shift measurements needed for high resolution electron backscatter diffraction strain mapping can be obtained. We also show that the physics underlying direct detection is sufficiently well understood at low primary electron energies such that simulated patterns can be generated to verify our experimental data

Fast Entropy Estimation for Natural Sequences

It is well known that to estimate the Shannon entropy for symbolic sequences accurately requires a large number of samples. When some aspects of the data are known it is plausible to attempt to use this to more efficiently compute entropy. A number of methods having various assumptions have been proposed which can be used to calculate entropy for small sample sizes. In this paper, we examine this problem and propose a method for estimating the Shannon entropy for a set of ranked symbolic natural events. Using a modified Zipf-Mandelbrot-Li law and a new rank-based coincidence counting method, we propose an efficient algorithm which enables the entropy to be estimated with surprising accuracy using only a small number of samples. The algorithm is tested on some natural sequences and shown to yield accurate results with very small amounts of data

Co-morbidity burden in Parkinson’s disease : Comparison with controls and its influence on prognosis

Financial support This study was funded by Parkinson’s UK, the Scottish Chief Scientist Office, NHS Grampian endowments, the BMA Doris Hillier award, RS Macdonald Trust, the BUPA Foundation, and SPRING. The funders had no involvement in the study. Acknowledgements We acknowledge funding for the PINE study from Parkinson’s UK (G-0502, G-0914, G-1302), the Scottish Chief Scientist Office(CAF/12/05), the BMA Doris Hillier award, RS Macdonald Trust, the BUPA Foundation, NHS Grampian endowments and SPRING. We thank the patients and controls for their participation and the research staff who collected data and supported the study database.Peer reviewedPostprintPostprintPublisher PD

Quantum Interference and Inelastic Scattering in a Model Which-Way Device

A which-way device is one which is designed to detect which of 2 paths is taken by a quantum particle, whether Schr\"odinger's cat is dead or alive. One possible such device is represented by an Aharonov-Bohm ring with a quantum dot on one branch. A charged cantilever or spring is brought close to the dot as a detector of the presence of an electron. The conventional view of such a device is that any change in the state of the cantilever implies a change in the electron state which will in turn destroy the interference effects. In this paper we show that it is in fact possible to change the state of the oscillator while preserving the quantum interference phenomenon.Comment: 5 pages, 7 figures, Localisation 2002 Toky

Seismic structure and earthquake focal mechanisms of the Hengill volcanic complex, S W Iceland

Iceland provides a unique opportunity to study the processes that occur along mid- ocean ridges. In 1991, thirty temporary seismic stations were installed at the Hengill volcanic complex to record high-quality digital data from local earthquakes. From these data 449 earthquakes have been located, most of them beneath the geothermal area. A local earthquake tomographic inversion was carried out to determine the three- dimensional V(_p) and V(_p) /V(_s) structure to 6 km depth, using P-wave travel times and S-P times from local earthquakes recorded in 1981 and 1991. The resulting models are smoothly varying and give a low data variance. The V(_p) model is similar to that of a previous tomographic inversion in the area, although the models differ in detail. The main high-V(_p) features of these models are interpreted as solidified intrusions, and underlie extinct volcanic centres. A low V(_p) /V(_s) body (-4%) is detected from 0 to 3 km depth that correlates with the surface expression of the geothermal field and is probably due to a combination of effects that include a slightly lower pore fluid pressure (and thus a higher steam content), and rock matrix alteration. Well-constrained moment tensors were determined for 70 local earthquakes by inverting the polarities and amplitude ratios of P and S arrivals. This method works well and is relatively insensitive to wave-speed model and attenuation variations. Most of the earthquakes are non-double-couple with explosive volumetric components. Only 17 (28%) of the earthquakes are consistent with a double-couple model. The remaining earthquakes are modelled as a combination of an opening tensile crack and a shear fault. Two geometries are considered: (1) rupture on two separate fault planes aligned at 45º, and (2) opening-shear rupture on a single fault plane, which is equivalent to coplanar tensile and shear faults. Both models can give the same moment tensors, and the data cannot distinguish between them. They give a good fit to the data, with few polarity misfits for most of the earthquakes. Right-lateral opening-shear strike-slip faulting on near-vertical planes is consistent with the regional seismicity of the South Iceland Seismic Zone. The non-double-couple earthquakes may result from the regional stress regime interacting with the geothermal field

Dual ion beam deposition of carbon films with diamondlike properties

A single and dual ion beam system was used to generate amorphous carbon films with diamond like properties. A methane/argon mixture at a molar ratio of 0.28 was ionized in the low pressure discharge chamber of a 30-cm-diameter ion source. A second ion source, 8 cm in diameter was used to direct a beam of 600 eV Argon ions on the substrates (fused silica or silicon) while the deposition from the 30-cm ion source was taking place. Nuclear reaction and combustion analysis indicate H/C ratios for the films to be 1.00. This high value of H/C, it is felt, allowed the films to have good transmittance. The films were impervious to reagents which dissolve graphitic and polymeric carbon structures. Although the measured density of the films was approximately 1.8 gm/cu cm, a value lower than diamond, the films exhibited other properties that were relatively close to diamond. These films were compared with diamondlike films generated by sputtering a graphite target

Natural Enemies of Cranberry Fruitworm, \u3ci\u3eAcrobasis Vaccinii\u3c/i\u3e, (Lepidoptera: Pyraudae) in Michigan Highbush Blueberries

A two-year study was conducted in Michigan highbush blueberries to determine the complex of parasitoids attacking cranberry fruitworm, Acrobasis vaccinii. Eight parasitoid species and one fungal pathogen were collected. Parasitism of collected hosts ranged from 6.6% to 28.1%. The more common larval parasitoid encountered was Campoletis patsuiketorum (Hymenoptera: Ichneumonidae). The more common parasitoid recovered from fruitworm hibernacula was Villa lateralis (Diptera: Bombyliidae). This study documented six unreported natural enemies of cranberry fruitworm, including C. patsuiketorum; V. lateralis; Diadegma compressum (Hymenoptera: Ichneumonidae); Compsilura concinnata (Diptera: Tachinidae); Memorilla pyste (Diptera: Tachinidae); an undescribed Microtypus species (Hymenoptera: Braconidae); and a fungal pathogen, Paecilomyces near farinosus. This is the first known host association for the undescribed Microtypus species, and increases the known parasitoid complex of cranberry fruitworm to 17 species

Spatial mapping of splicing factor complexes involved in exon and intron definition

We have analyzed the interaction between serine/arginine-rich (SR) proteins and splicing components that recognize either the 5′ or 3′ splice site. Previously, these interactions have been extensively characterized biochemically and are critical for both intron and exon definition. We use fluorescence resonance energy transfer (FRET) microscopy to identify interactions of individual SR proteins with the U1 small nuclear ribonucleoprotein (snRNP)–associated 70-kD protein (U1 70K) and with the small subunit of the U2 snRNP auxiliary factor (U2AF35) in live-cell nuclei. We find that these interactions occur in the presence of RNA polymerase II inhibitors, demonstrating that they are not exclusively cotranscriptional. Using FRET imaging by means of fluorescence lifetime imaging microscopy (FLIM), we map these interactions to specific sites in the nucleus. The FLIM data also reveal a previously unknown interaction between HCC1, a factor related to U2AF65, with both subunits of U2AF. Spatial mapping using FLIM-FRET reveals differences in splicing factors interactions within complexes located in separate subnuclear domains