Causes and Predictors of Thematic Intrusion on Human Similarity Judgments

Most theoretical accounts of psychological similarity maintain that similarity judgments are based on shared features (and shared relations among those features, e.g., the commonalities between spatula and ladle). Accounts rarely include associations between targets of comparison (e.g., the association between egg and spatula) as a contributor to similarity judgments. This position is taken despite the fact that people will often choose associates over things with shared features and relations in similarity judgment tasks. So-called dual-process models - where thematic integration and feature (and relation) based comparison are component processes of perceived human similarity - have been proposed to handle this apparent failure to account for human similarity judgments. The present experiments were designed to further explore the thematic association effect on similarity with the goal to test the hypothesis that confusion about similarity and association (rather than a radical theoretical redirection, e.g., the dual-process model) is the cause of the reported thematic association influence on similarity judgments. Experiment 1 introduces a novel task for collecting similarity judgments of real world concepts - the Anti-Thematic Intrusion (ATI) task - and tests alternative task instructions as a possible driver of thematic intrusion on similarity. Experiment 2 examines the effect of the isolated components of the ATI task as compared to the classic two-alternative, forced choice similarity judgment task to determine what changes from the classic task are most influential for reducing thematic intrusion. Experiment 3 was conducted to confirm that the concept sets used in Experiments 1 and 2 did not produce biased responding. Having explored task, instruction and concept-based effects, Experiment 4 investigated behavioral and electrophysiological differences among individuals to attempt to clarify how differences between individuals correspond to similarity judgment behavior. The results were not expected in that the strength of the thematic association effect on similarity was weaker than predicted; Experiments 1, 2, and 4 show that overall association-based preferences were only present in situations strongly biased toward producing that response type. It was also found that taxonomic pair matching reliably increased across the time course of the task. Changes in the properties of the task and the instructions attenuate the effect, suggesting that the intrusion of thematic relationships on similarity judgments is not an unyielding feature of the similarity judgment process (as dual-process accounts propose) but instead (at least in part) due to interpretation of the task goal and confusion about similarity and association-based relatedness. Finally, this confusion is identifiable by less differentiation in the EEG signal elicited by these competing semantic relations, where people who produce more similarity-based responding also produce more distinctive ERP waveforms for taxonomic and thematic category members

Geologic setting and stratigraphy of the Ziegler Reservoir fossil site, Snowmass Village, Colorado

The geologic setting of the Ziegler Reservoir fossil site is somewhat unusual—the sediments containing the Pleistocene fossils were deposited in a lake on top of a ridge. The lake basin was formed near Snowmass Village, Colorado (USA) when a glacier flowing down Snowmass Creek Valley became thick enough to overtop a low point in the eastern valley wall and entered the head of Brush Creek Valley. When the glacier retreated at about 155–130 ka, near the end of Marine Oxygen Isotope Stage 6, the Brush Creek Valley lobe left behind a moraine that impounded a small alpine lake. The lake was initially ~10m deep and appears to have been highly productive during most of its existence, based on the abundant and exquisitely preserved organic material present in the sediments. Over time, the basin slowly filled with (mostly) eolian sediment such that by ~87 ka it contained a marsh or wetland rather than a true lake. Open-water conditions returned briefly between ~77 and 55 ka before the impoundment was finally breached to the east, establishing ties with the Brush Creek drainage system and creating an alpine meadow that persisted until historic times

Geologic setting and stratigraphy of the Ziegler Reservoir fossil site, Snowmass Village, Colorado

The geologic setting of the Ziegler Reservoir fossil site is somewhat unusual—the sediments containing the Pleistocene fossils were deposited in a lake on top of a ridge. The lake basin was formed near Snowmass Village, Colorado (USA) when a glacier flowing down Snowmass Creek Valley became thick enough to overtop a low point in the eastern valley wall and entered the head of Brush Creek Valley. When the glacier retreated at about 155–130 ka, near the end of Marine Oxygen Isotope Stage 6, the Brush Creek Valley lobe left behind a moraine that impounded a small alpine lake. The lake was initially ~10m deep and appears to have been highly productive during most of its existence, based on the abundant and exquisitely preserved organic material present in the sediments. Over time, the basin slowly filled with (mostly) eolian sediment such that by ~87 ka it contained a marsh or wetland rather than a true lake. Open-water conditions returned briefly between ~77 and 55 ka before the impoundment was finally breached to the east, establishing ties with the Brush Creek drainage system and creating an alpine meadow that persisted until historic times

Two-vibron bound states in alpha-helix proteins : the interplay between the intramolecular anharmonicity and the strong vibron-phonon coupling

The influence of the intramolecular anharmonicity and the strong vibron-phonon coupling on the two-vibron dynamics in an $\alpha$-helix protein is studied within a modified Davydov model. The intramolecular anharmonicity of each amide-I vibration is considered and the vibron dynamics is described according to the small polaron approach. A unitary transformation is performed to remove the intramolecular anharmonicity and a modified Lang-Firsov transformation is applied to renormalize the vibron-phonon interaction. Then, a mean field procedure is realized to obtain the dressed anharmonic vibron Hamiltonian. It is shown that the anharmonicity modifies the vibron-phonon interaction which results in an enhancement of the dressing effect. In addition, both the anharmonicity and the dressing favor the occurrence of two different bound states which the properties strongly depend on the interplay between the anharmonicity and the dressing. Such a dependence was summarized in a phase diagram which characterizes the number and the nature of the bound states as a function of the relevant parameters of the problem. For a significant anharmonicity, the low frequency bound states describe two vibrons trapped onto the same amide-I vibration whereas the high frequency bound states refer to the trapping of the two vibrons onto nearest neighbor amide-I vibrations.Comment: may 2003 submitted to Phys. Rev.

Phonons and related properties of extended systems from density-functional perturbation theory

This article reviews the current status of lattice-dynamical calculations in crystals, using density-functional perturbation theory, with emphasis on the plane-wave pseudo-potential method. Several specialized topics are treated, including the implementation for metals, the calculation of the response to macroscopic electric fields and their relevance to long wave-length vibrations in polar materials, the response to strain deformations, and higher-order responses. The success of this methodology is demonstrated with a number of applications existing in the literature.Comment: 52 pages, 14 figures, submitted to Review of Modern Physic

Controlled Crystallization of the Amorphous Phase in Silicon Nitride Ceramics

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65986/1/j.1151-2916.1987.tb05676.x.pd

Independent age estimates resolve the controversy of ancient human footprints at White Sands

Human footprints at White Sands National Park, New Mexico, USA, reportedly date to between ~23,000 and 21,000 years ago according to radiocarbon dating of seeds from the aquatic plant Ruppia cirrhosa. These ages remain controversial because of potential old carbon reservoir effects that could compromise their accuracy. We present new calibrated 14C ages of terrestrial pollen collected from the same stratigraphic horizons as those of the Ruppia seeds, along with optically stimulated luminescence ages of sediments from within the human footprint–bearing sequence, to evaluate the veracity of the seed ages. The results show that the chronologic framework originally established for the White Sands footprints is robust and reaffirm that humans were present in North America during the Last Glacial Maximum

Tumor Necrosis Factor-mediated survival of CD169⁺ cells promotes immune activation during vesicular stomatitis virus infection

Innate immune activation is essential to mount an effective antiviral response and to prime adaptive immunity. Although a crucial role of CD169+ cells during vesicular stomatitis virus (VSV) infections is increasingly recognized, factors regulating CD169+ cells during viral infections remain unclear. Here, we show that tumor necrosis factor is produced by CD11b+ Ly6C+ Ly6G+ cells following infection with VSV. The absence of TNF or TNF receptor 1 (TNFR1) resulted in reduced numbers of CD169+ cells and in reduced type I interferon (IFN-I) production during VSV infection, with a severe disease outcome. Specifically, TNF triggered RelA translocation into the nuclei of CD169+ cells; this translocation was inhibited when the paracaspase MALT-1 was absent. Consequently, MALT1 deficiency resulted in reduced VSV replication, defective innate immune activation, and development of severe disease. These findings indicate that TNF mediates the maintenance of CD169+ cells and innate and adaptive immune activation during VSV infection

Increased numbers of oligodendrocyte lineage cells in the optic nerves of cerebroside sulfotransferase knockout mice

Sulfatide is a myelin glycolipid that functions in the formation of paranodal axo-glial junctions in vivo and in the regulation of oligodendrocyte differentiation in vitro. Cerebroside sulfotransferase (CST) catalyzes the production of two sulfated glycolipids, sulfatide and proligodendroblast antigen, in oligodendrocyte lineage cells. Recent studies have demonstrated significant increases in oligodendrocytes from the myelination stage through adulthood in brain and spinal cord under CST-deficient conditions. However, whether these result from excess migration or in situ proliferation during development is undetermined. In the present study, CST-deficient optic nerves were used to examine migration and proliferation of oligodendrocyte precursor cells (OPCs) under sulfated glycolipid-deficient conditions. In adults, more NG2-positive OPCs and fully differentiated cells were observed. In developing optic nerves, the number of cells at the leading edge of migration was similar in CST-deficient and wild-type mice. However, BrdU+ proliferating OPCs were more abundant in CST-deficient mice. These results suggest that sulfated glycolipids may be involved in proliferation of OPCs in vivo

Relaxation channels of two-vibron bound states in \alpha-helix proteins

Relaxation channels for two-vibron bound states in an anharmonic alpha-helix protein are studied. It is pointed out that the relaxation originates in the interaction between the dressed anharmonic vibrons and the remaining phonons. This interaction is responsible for the occurrence of transitions between two-vibron eigenstates mediated by both phonon absorption and phonon emission. At biological temperature, it is shown that the relaxation rate does not significantly depends on the nature of the two-vibron state involved in the process. Therefore, the lifetime for both bound and free states is of the same order of magnitude and ranges between 0.1 and 1.0 ps for realistic parameters. By contrast, the relaxation channels strongly depend on the nature of the two-vibron states which is a consequence of the breather-like behavior of the two-vibron bound states.Comment: octobre 2003 - soumis Phys. Rev.