26,216 research outputs found
Tapping to a slow tempo in the presence of simple and complex musical meters reveals experience-specific biases for processing music
Musical meters vary considerably across cultures, yet relatively little is known about how culture-specific experience influences metrical processing. In Experiment 1, we compared American and Indian listeners\u27 synchronous tapping to slow sequences. Inter-tone intervals contained silence or to-be-ignored rhythms that were designed to induce a simple meter (familiar to Americans and Indians) or a complex meter (familiar only to Indians). A subset of trials contained an abrupt switch from one rhythm to another to assess the disruptive effects of contradicting the initially implied meter. In the unfilled condition, both groups tapped earlier than the target and showed large tap-tone asynchronies (measured in relative phase). When inter-tone intervals were filled with simple-meter rhythms, American listeners tapped later than targets, but their asynchronies were smaller and declined more rapidly. Likewise, asynchronies rose sharply following a switch away from simple-meter but not from complex-meter rhythm. By contrast, Indian listeners performed similarly across all rhythm types, with asynchronies rapidly declining over the course of complex- and simple-meter trials. For these listeners, a switch from either simple or complex meter increased asynchronies. Experiment 2 tested American listeners but doubled the duration of the synchronization phase prior to (and after) the switch. Here, compared with simple meters, complex-meter rhythms elicited larger asynchronies that declined at a slower rate, however, asynchronies increased after the switch for all conditions. Our results provide evidence that ease of meter processing depends to a great extent on the amount of experience with specific meters
Reduction of lattice thermal conductivity from planar faults in the layered Zintl compound SrZnSb_2
The layered Zintl compound SrZnSb_2 is investigated using transmission electron microscopy (TEM) to understand the low lattice thermal conductivity. The material displays out-of-phase boundaries with a spacing from 100 down to 2 nm. Density functional theory calculations confirm that the TEM-derived defect structure is energetically reasonable. The impact of these defects on phonon scattering is analyzed within the Debye–Callaway model, which reveals a significant reduction in the acoustic phonon mean free path. This enhancement in phonon scattering leads to an ~30% reduction in lattice thermal conductivity at 300 K
Nanoscale alpha-structural domains in the phonon-glass thermoelectric material beta-Zn4Sb3
A study of the local atomic structure of the promising thermoelectric material beta-Zn4Sb3, using atomic pair distribution function (PDF) analysis of x-ray- and neutron-diffraction data, suggests that the material is nanostructured. The local structure of the beta phase closely resembles that of the low-temperature alpha phase. The alpha structure contains ordered zinc interstitial atoms which are not long range ordered in the beta phase. A rough estimate of the domain size from a visual inspection of the PDF is <~10 nm. It is probable that the nanoscale domains found in this study play an important role in the exceptionally low thermal conductivity of beta-Zn4Sb3
Demixing kinetics of phase separated polymer solutions in microgravity
Phase separated solutions of two neutral polymers in buffer provide a useful and versatile medium for the partition separation of biological cells. However, the efficiency of such separations is orders of magnitude lower than the thermodynamic limit. To test the hypothesis that this inefficiency is at least partially due to the convection and sedimentation that occur during the gravity driven demixing that follows introduction of cells to the systems, a series of experiments were begun aimed at performing cell partition in a low g environment. Demixing of isopycnic three polymer solvent systems was studied, experiments were performed on KC-135 aircraft and one shuttle middeck experiment was completed. Analysis of the results of these experiments and comparisons with the predictions of scaling relations for the dependence of phase domain size on time, derived for a number of possible demixing mechanisms, are presented
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Less-structured time in children's daily lives predicts self-directed executive functioning.
Executive functions (EFs) in childhood predict important life outcomes. Thus, there is great interest in attempts to improve EFs early in life. Many interventions are led by trained adults, including structured training activities in the lab, and less-structured activities implemented in schools. Such programs have yielded gains in children's externally-driven executive functioning, where they are instructed on what goal-directed actions to carry out and when. However, it is less clear how children's experiences relate to their development of self-directed executive functioning, where they must determine on their own what goal-directed actions to carry out and when. We hypothesized that time spent in less-structured activities would give children opportunities to practice self-directed executive functioning, and lead to benefits. To investigate this possibility, we collected information from parents about their 6-7 year-old children's daily, annual, and typical schedules. We categorized children's activities as "structured" or "less-structured" based on categorization schemes from prior studies on child leisure time use. We assessed children's self-directed executive functioning using a well-established verbal fluency task, in which children generate members of a category and can decide on their own when to switch from one subcategory to another. The more time that children spent in less-structured activities, the better their self-directed executive functioning. The opposite was true of structured activities, which predicted poorer self-directed executive functioning. These relationships were robust (holding across increasingly strict classifications of structured and less-structured time) and specific (time use did not predict externally-driven executive functioning). We discuss implications, caveats, and ways in which potential interpretations can be distinguished in future work, to advance an understanding of this fundamental aspect of growing up
Thermoelectric properties of Zn_5Sb_4In_(2-δ)(δ=0.15)
The polymorphic intermetallic compound Zn_5Sb_4In_(2−δ) (δ = 0.15(3)) shows promising thermoelectric properties at low temperatures, approaching a figure of merit ZT of 0.3 at 300 K. However, thermopower and electrical resistivity changes discontinuously at around 220 K. Measurement of the specific heat locates the previously unknown temperature of the order-disorder phase transition at around 180 K. Investigation of the charge carrier concentration and mobility by Hall measurements and infrared reflection spectroscopy indicate a mixed conduction behavior and the activation of charge carriers at temperatures above 220 K. Zn_5Sb_4In_(2−δ) has a low thermal stability, and at temperatures above 470 K samples decompose into a mixture of Zn, InSb, and Zn_4Sb_3
Archeota, Fall 2019
This is the Fall 2019 issue of Archeota, the official publication of SJSU SAASC.
Archeota is a platform for students to contribute to the archival conversation. It is written BY students, FOR students. It provides substantive content on archival concerns and issues, and promotes career development in the field of archival studies. Archeota upholds the core values of the archival profession. It is a semiannual publication of the Student Chapter of the Society of American Archivists at the San Jose State University School of Information.https://scholarworks.sjsu.edu/saasc_archeota/1010/thumbnail.jp
Contracted Representation of Yang's Space-Time Algebra and Buniy-Hsu-Zee's Discrete Space-Time
Motivated by the recent proposition by Buniy, Hsu and Zee with respect to
discrete space-time and finite spatial degrees of freedom of our physical world
with a short- and a long-distance scales, and we reconsider the
Lorentz-covariant Yang's quantized space-time algebra (YSTA), which is
intrinsically equipped with such two kinds of scale parameters, and
. In accordance with their proposition, we find the so-called contracted
representation of YSTA with finite spatial degrees of freedom associated with
the ratio , which gives a possibility of the divergence-free
noncommutative field theory on YSTA. The canonical commutation relations
familiar in the ordinary quantum mechanics appear as the cooperative
Inonu-Wigner's contraction limit of YSTA, and $R \to \infty.
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