800 research outputs found
Neutral evolution and turnover over centuries of English word popularity
Here we test Neutral models against the evolution of English word frequency
and vocabulary at the population scale, as recorded in annual word frequencies
from three centuries of English language books. Against these data, we test
both static and dynamic predictions of two neutral models, including the
relation between corpus size and vocabulary size, frequency distributions, and
turnover within those frequency distributions. Although a commonly used Neutral
model fails to replicate all these emergent properties at once, we find that
modified two-stage Neutral model does replicate the static and dynamic
properties of the corpus data. This two-stage model is meant to represent a
relatively small corpus (population) of English books, analogous to a `canon',
sampled by an exponentially increasing corpus of books in the wider population
of authors. More broadly, this mode -- a smaller neutral model within a larger
neutral model -- could represent more broadly those situations where mass
attention is focused on a small subset of the cultural variants.Comment: 12 pages, 5 figures, 1 tabl
Applications of a High-Altitude Powered Platform (HAPP)
A list of potential uses for the (HAPP) and conceptual system designs for a small subset of the most promising applications were investigated. The method was to postulate a scenario for each application specifying a user, a set of system requirements and the most likely competitor among conventional aircraft and satellite systems. As part of the study of remote sensing applications, a parametric cost comparison was done between aircraft and HAPPS. For most remote sensing applications, aircraft can supply the same data as HAPPs at substantially lower cost. The critical parameters in determining the relative costs of the two systems are the sensor field of view and the required frequency of the observations being made. The HAPP is only competitive with an airplane when sensors having a very wide field of view are appropriate and when the phenomenon being observed must be viewed at least once per day. This eliminates the majority of remote sensing applications from any further consideration
Cultural prerequisites of socioeconomic development
In the centuries since the enlightenment, the world has seen an increase in socioeconomic development, measured as increased life expectancy, education, economic development and democracy. While the co-occurrence of these features among nations is well documented, little is known about their origins or co-evolution. Here, we compare this growth of prosperity in nations to the historical record of cultural values in the twentieth century, derived from global survey data. We find that two cultural factors, secular-rationality and cosmopolitanism, predict future increases in GDP per capita, democratization and secondary education enrollment. The converse is not true, however, which indicates that secular-rationality and cosmopolitanism are among the preconditions for socioeconomic development to emerge
Cultural values predict national COVID-19 death rates
National responses to a pandemic require populations to comply through personal behaviors that occur in a cultural context. Here we show that aggregated cultural values of nations, derived from World Values Survey data, have been at least as important as top-down government actions in predicting the impact of COVID-19. At the population level, the cultural factor of cosmopolitanism, together with obesity, predict higher numbers of deaths in the first two months of COVID-19 on the scale of nations. At the state level, the complementary variables of government efficiency and public trust in institutions predict lower death numbers. The difference in effect between individual beliefs and behaviors, versus state-level actions, suggests that open cosmopolitan societies may face greater challenges in limiting a future pandemic or other event requiring a coordinated national response among the population. More generally, mass cultural values should be considered in crisis preparations
Spin/orbit moment imbalance in the near-zero moment ferromagnetic semiconductor SmN
SmN is ferromagnetic below 27 K, and its net magnetic moment of 0.03 Bohr
magnetons per formula unit is one of the smallest magnetisations found in any
ferromagnetic material. The near-zero moment is a result of the nearly equal
and opposing spin and orbital moments in the 6H5/2 ground state of the Sm3+
ion, which leads finally to a nearly complete cancellation for an ion in the
SmN ferromagnetic state. Here we explore the spin alignment in this compound
with X-ray magnetic circular dichroism at the Sm L2,3 edges. The spectral
shapes are in qualitative agreement with computed spectra based on an LSDA+U
(local spin density approximation with Hubbard-U corrections) band structure,
though there remain differences in detail which we associate with the anomalous
branching ratio in rare-earth L edges. The sign of the spectra determine that
in a magnetic field the Sm 4f spin moment aligns antiparallel to the field; the
very small residual moment in ferromagnetic SmN aligns with the 4f orbital
moment and antiparallel to the spin moment. Further measurements on very thin
(1.5 nm) SmN layers embedded in GdN show the opposite alignment due to a strong
Gd-Sm exchange, suggesting that the SmN moment might be further reduced by
about 0.5 % Gd substitution
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