Dynamical Monodromy

Integrable Hamiltonian systems are said to display nontrivial monodromy if fundamental action-angle loops defined on phase-space tori change their topological structure when the system is carried around a circuit. In an earlier paper it was shown that this topological change can occur as a result of time evolution under certain rather abstract flows in phase space. In the present paper, we show that the same topological change can occur as a result of application of ordinary forces. We also show how this dynamical phenomenon could be observed experimentally in classical or in quantum systems

Special Issue on Surveillance: Editor’s Introduction

This Editor’s Introduction discusses the interplay of surveillance issues with media and communication research

Ballistic Atom Pumps

We examine a classically chaotic system consisting of two reservoirs of particles connected by a channel containing oscillating potential-energy barriers. We investigate whether such a system can preferentially pump particles from one reservoir to the other, a process often called “quantum pumping.” We show how to make a “particle diode” which under specified conditions permits net particle pumping in only one direction. Then we examine systems having symmetric barriers. We find that if all initial particle energies are considered, a system with symmetric barriers cannot preferentially pump particles. However, if only finite initial energy bands are considered, the system can create net particle transport in either direction. We study the system classically, semiclassically, and quantum mechanically, and find that the quantum description cannot be fully understood without the insight gained from classical and semiclassical analysis

Scattering By an Oscillating Barrier: Quantum, Classical, and Semiclassical Comparison

We present a detailed study of scattering by an amplitude-modulated potential barrier using three distinct physical frameworks: quantum, classical, and semiclassical. Classical physics gives bounds on the energy and momentum of the scattered particle, while also providing the foundation for semiclassical theory. We use the semiclassical approach to selectively add quantum-mechanical effects such as interference and diffraction. We find good agreement between the quantum and semiclassical momentum distributions. Our methods and results can be used to understand quantum and classical aspects of transport mechanisms involving time-varying potentials, such as quantum pumping

Trust in Healthcare and Trust in Science Predict Readiness to Receive the COVID-19 Vaccine in Appalachia

BACKGROUND: The Appalachian Region faces multiple barriers to widespread COVID-19 vaccination. The purpose of this research study was to explore the role of trust in healthcare and trust in science on Appalachian residents’ readiness to receive the COVID-19 vaccine. Trust in health influencers and health information sources were also explored. METHODS: A cross sectional survey study of Appalachian Region residents (n=1048) was completed between February 25 and March 6, 2021, with equivalent rural and non-rural sampling methods employed. Participants were >35 years of age and had not received the COVID-19 vaccine at the time of survey administration. RESULTS: Overall, 31% of participants were extremely likely to receive the vaccine, while 42% were somewhat likely/neither unlikely or likely/somewhat unlikely, and 27% were extremely unlikely. Based on multiple linear regression analysis with backwards selection, trust in healthcare, trust in science, residence (rural vs. non-rural) and age were positive predictors of readiness to receive the vaccine (F(5, 1042)= 38.9, R2= 0.157, p< 0.01). Gender, education, household income, and political affiliation did not predict vaccine readiness. Trust in media for health information was modest, with ratings of none or not much for social media (64%), podcasts (61%), magazines (46%), radio (37%), newspapers (36%), and television (35%). Primary care providers emerged as the highest trusted health influencer of 15 options and a primary care provider’s office was the most common preference for location for receiving the COVID-19 vaccine, particularly in participants who rated themselves as extremely unlikely to receive the COVID-19 vaccine. CONCLUSIONS: These findings suggest that trust in healthcare and science are prospective foci for initiatives aimed at improving vaccine acceptance in Appalachia, particularly in younger residents of rural areas. As highly trusted health influencers, primary care providers should be leveraged and supported in COVID-19 vaccine education and distribution.http://deepblue.lib.umich.edu/bitstream/2027.42/167136/1/AFM_273_21_PP.pdfDescription of AFM_273_21_PP.pdf : Main ArticleSEL

Understanding Why Scholars Hold Different Views on the Influences of Video Games on Public Health

Despite decades of research, no scholarly consensus has been achieved regarding the potential impact of video games on youth aggression or other public health concerns. In recent years, hypotheses have been raised that scholarly opinions on video games may resemble past moral panics, with attitudes reflective of generational conflicts. These hypotheses are tested in a sample of 175 criminologists, psychologists and media scholars, examining both overall negative attitudes about video games and perceived linkages with youth assaults specifically. Results reflected continued lack of scholarly consensus on the issue of video game influences with only 15.3% of scholars endorsing the view the violent video games contribute to youth assaults. As hypothesized, older scholars endorsed more negative views of video games generally, although this appeared to be related to experience with games rather than age per se. Scholars with more negative attitudes toward youth themselves were also more negative about games. Criminologists and media scholars were more skeptical of violent video games contributing to youth assaults than were psychologists. These results are discussed in relation to Moral Panic Theory

Continuous 1.3-Million-Year Record of East African Hydroclimate, and Implications for Patterns of Evolution and Biodiversity

The transport of moisture in the tropics is a critical process for the global energy budget and on geologic timescales, has markedly influenced continental landscapes, migratory pathways, and biological evolution. Here we present a continuous, first-of-its-kind 1.3-My record of continental hydroclimate and lake-level variability derived from drill core data from Lake Malawi, East Africa (9–15° S). Over the Quaternary, we observe dramatic shifts in effective moisture, resulting in large-scale changes in one of the world’s largest lakes and most diverse freshwater ecosystems. Results show evidence for 24 lake level drops of more than 200 m during the Late Quaternary, including 15 lowstands when water levels were more than 400 m lower than modern. A dramatic shift is observed at the Mid-Pleistocene Transition (MPT), consistent with far-field climate forcing, which separates vastly different hydroclimate regimes before and after ∼800,000 years ago. Before 800 ka, lake levels were lower, indicating a climate drier than today, and water levels changed frequently. Following the MPT high-amplitude lake level variations dominate the record. From 800 to 100 ka, a deep, often overfilled lake occupied the basin, indicating a wetter climate, but these highstands were interrupted by prolonged intervals of extreme drought. Periods of high lake level are observed during times of high eccentricity. The extreme hydroclimate variability exerted a profound influence on the Lake Malawi endemic cichlid fish species flock; the geographically extensive habitat reconfiguration provided novel ecological opportunities, enabling new populations to differentiate rapidly to distinct species

Ecological consequences of early Late Pleistocene megadroughts in tropical Africa

Extremely arid conditions in tropical Africa occurred in several discrete episodes between 135 and 90 ka, as demonstrated by lake core and seismic records from multiple basins [Scholz CA, Johnson TC, Cohen AS, King JW, Peck J, Overpeck JT, Talbot MR, Brown ET, Kalindekafe L, Amoako PYO, et al. (2007) Proc Natl Acad Sci USA 104:16416–16421]. This resulted in extraordinarily low lake levels, even in Africa\u27s deepest lakes. On the basis of well dated paleoecological records from Lake Malawi, which reflect both local and regional conditions, we show that this aridity had severe consequences for terrestrial and aquatic ecosystems. During the most arid phase, there was extremely low pollen production and limited charred-particle deposition, indicating insufficient vegetation to maintain substantial fires, and the Lake Malawi watershed experienced cool, semidesert conditions (\u3c400 mm/yr precipitation). Fossil and sedimentological data show that Lake Malawi itself, currently 706 m deep, was reduced to an ≈125 m deep saline, alkaline, well mixed lake. This episode of aridity was far more extreme than any experienced in the Afrotropics during the Last Glacial Maximum (≈35–15 ka). Aridity diminished after 95 ka, lake levels rose erratically, and salinity/alkalinity declined, reaching near-modern conditions after 60 ka. This record of lake levels and changing limnological conditions provides a framework for interpreting the evolution of the Lake Malawi fish and invertebrate species flocks. Moreover, this record, coupled with other regional records of early Late Pleistocene aridity, places new constraints on models of Afrotropical biogeographic refugia and early modern human population expansion into and out of tropical Africa