797 research outputs found
A Case Study: Observations of Behaviors & Vocalizations in a Captive Asian Elephant (Elephas maximus) During Quarantine
Bozie, an Asian elephant (Elephas maximus), was relocated from the Baton Rouge Zoo to Smithsonian’s National Zoo. During a requisite 29-day quarantine period, I recorded Bozie’s stress-related behaviors and the vocalizations she produced when she was alone and with her keepers in free and protected contact
A universal relationship between magnetization and local structure changes below the ferromagnetic transition in La_{1-x}Ca_xMnO_3; evidence for magnetic dimers
We present extensive X-ray Absorption Fine Structure (XAFS) measurements on
La_{1-x}Ca_xMnO_3 as a function of B-field (to 11T) and Ca concentration, x
(21-45%). These results reveal local structure changes (associated with polaron
formation) that depend only on the magnetization for a given sample,
irrespective of whether the magnetization is achieved through a decrease in
temperature or an applied magnetic field. Furthermore, the relationship between
local structure and magnetization depends on the hole doping. A model is
proposed in which a filamentary magnetization initially develops via the
aggregation of pairs of Mn atoms involving a hole and an electron site. These
pairs have little distortion and it is likely that they pre-form at
temperatures above T_c.Comment: 5 pages, 5 figures (1 with 2 parts) -- v2. new data added (updated
figures); discussion expande
QAnon Propaganda on Twitter as Information Warfare: Influencers, Networks, and Narratives
QAnon refers to a set of far-right, conspiratorial ideologies that have risen
in popularity in the U.S. since their initial promotion in 2017 on the 4chan
internet message board. A central narrative element of QAnon is that a powerful
group of elite, liberal members of the Democratic Party engage in morally
reprehensible practices, but that former U.S. President Donald J. Trump was
prosecuting them. Five studies investigated the influence and network
connectivity of accounts promoting QAnon on Twitter from August, 2020 through
January, 2021. Selection of Twitter accounts emphasized on-line influencers and
"persons of interest" known or suspected of participation in QAnon propaganda
promotion activities. Evidence of large-scale coordination among accounts
promoting QAnon was observed, demonstrating rigorous, quantitative evidence of
"astroturfing" in QAnon propaganda promotion on Twitter, as opposed to strictly
"grassroots" activities of citizens acting independently. Further, evidence was
obtained supporting that networks of extreme far-right adherents engaged in
organized QAnon propaganda promotion, as revealed by network overlap among
accounts promoting far-right extremist (e.g., anti-Semitic) content and
insurrectionist themes; New Age, occult, and "esoteric" themes; and internet
puzzle games like Cicada 3301 and other "alternate reality games." Based on
well-grounded theories and findings from the social sciences, it is argued that
QAnon propaganda on Twitter in the months circa the 2020 U.S. Presidential
election likely reflected joint participation of multiple actors, including
nation-states like Russia, in innovative misuse of social media toward
undermining democratic processes by promoting "magical" thinking, ostracism of
Democrats and liberals, and salience of White extinction narratives common
among otherwise ideologically diverse groups on the extreme far-right.Comment: 60 pages, 14 figure
Observation of ferromagnetism above 900 K in Cr-GaN and Cr-AlN
We report the observation of ferromagnetism at over 900K in Cr-GaN and Cr-AlN
thin films. The saturation magnetization moments in our best films of Cr-GaN
and Cr-AlN at low temperatures are 0.42 and 0.6 u_B/Cr atom, respectively,
indicating that 14% and 20%, of the Cr atoms, respectively, are magnetically
active. While Cr-AlN is highly resistive, Cr-GaN exhibits thermally activated
conduction that follows the exponential law expected for variable range hopping
between localized states. Hall measurements on a Cr-GaN sample indicate a
mobility of 0.06 cm^2/V.s, which falls in the range characteristic of hopping
conduction, and a free carrier density (1.4E20/cm^3), which is similar in
magnitude to the measured magnetically-active Cr concentration (4.9E19/cm^3). A
large negative magnetoresistance is attributed to scattering from loose spins
associated with non-ferromagnetic impurities. The results indicate that
ferromagnetism in Cr-GaN and Cr-AlN can be attributed to the double exchange
mechanism as a result of hopping between near-midgap substitutional Cr impurity
bands.Comment: 14 pages, 4 figures, submitted to AP
Culture and trade through the prism of technical art history: a study of Chinese export paintings
Photonic Quantum Logic with Narrowband Light from Single Atoms
Increasing control of single photons enables new applications of photonic
quantum-enhanced technology and further experimental exploration of fundamental
quantum phenomena. Here, we demonstrate quantum logic using narrow linewidth
photons that are produced under nearly perfect quantum control from a single
^87Rb atom strongly coupled to a high-finesse cavity. We use a controlled- NOT
gate integrated into a photonic chip to entangle these photons, and we observe
non-classical correlations between events separated by periods exceeding the
travel time across the chip by three orders of magnitude. This enables quantum
technology that will use the properties of both narrowband single photon
sources and integrated quantum photonics, such as networked quantum computing,
narrow linewidth quantum enhanced sensing and atomic memories.Comment: 5 pates, 3 figure
Testing hypotheses about the harm that capitalism causes to the mind and brain: a theoretical framework for neuroscience research
In this paper, we will attempt to outline the key ideas of a theoretical framework for neuroscience research that reflects critically on the neoliberal capitalist context. We argue that neuroscience can and should illuminate the effects of neoliberal capitalism on the brains and minds of the population living under such socioeconomic systems. Firstly, we review the available empirical research indicating that the socio-economic environment is harmful to minds and brains. We, then, describe the effects of the capitalist context on neuroscience itself by presenting how it has been influenced historically. In order to set out a theoretical framework that can generate neuroscientific hypotheses with regard to the effects of the capitalist context on brains and minds, we suggest a categorization of the effects, namely deprivation, isolation and intersectional effects. We also argue in favor of a neurodiversity perspective [as opposed to the dominant model of conceptualizing neural (mal-)functioning] and for a perspective that takes into account brain plasticity and potential for change and adaptation. Lastly, we discuss the specific needs for future research as well as a frame for post-capitalist research
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