Structured light, transmission, and scattering

Numerous theoretical and experimental studies have established the principle that beams conveying orbital angular momentum offer a rich scope for information transfer. However, it is not clear how far it is practicable to operate such a concept at the single-photon level - especially when such a beam propagates through a system in which scattering can occur. In cases where scattering leads to photon deflection, it produces losses; however in terms of the retention of information content, there should be more concern over forward scattering. Based on a quantum electrodynamical formulation of theory, this paper aims to frame and resolve the key issues. A quantum amplitude is constructed for the representation of single and multiple scattering events in the propagation an individual photon, from a suitably structured beam. The analysis identifies potential limitations of principle, undermining complete fidelity of quantum information transmission

Music in sport and exercise: An update on research and application

The full text of this article can be viewed at the link below.In spring 1999, almost a decade ago, the first author published in The Sport Journal an article titled “Music in Sport and Exercise: Theory and Practice.” The present article’s origins are in that earlier work and the first author’s research while a master’s student at the United States Sports Academy in 1991–92. To a greater degree than in the original 1999 article, this article focuses on the applied aspects of music in sport and exercise. Moreover, it highlights some new research trends emanating not only from our own publications, but also from the work of other prominent researchers in the field. The content is oriented primarily towards the needs of athletes and coaches

Data standardization

With data rapidly becoming the lifeblood of the global economy, the ability to improve its use significantly affects both social and private welfare. Data standardization is key to facilitating and improving the use of data when data portability and interoperability are needed. Absent data standardization, a “Tower of Babel” of different databases may be created, limiting synergetic knowledge production. Based on interviews with data scientists, this Article identifies three main technological obstacles to data portability and interoperability: metadata uncertainties, data transfer obstacles, and missing data. It then explains how data standardization can remove at least some of these obstacles and lead to smoother data flows and better machine learning. The Article then identifies and analyzes additional effects of data standardization. As shown, data standardization has the potential to support a competitive and distributed data collection ecosystem and lead to easier policing in cases where rights are infringed or unjustified harms are created by data-fed algorithms. At the same time, increasing the scale and scope of data analysis can create negative externalities in the form of better profiling, increased harms to privacy, and cybersecurity harms. Standardization also has implications for investment and innovation, especially if lock-in to an inefficient standard occurs. The Article then explores whether market-led standardization initiatives can be relied upon to increase welfare, and the role governmental-facilitated data standardization should play, if at all

Metamodulation of a spinal locomotor network by nitric oxide

Flexibility in the output of spinal networks can be accomplished by the actions of neuromodulators; however, little is known about how the process of neuromodulation itself may be modulated. Here we investigate the potential "meta"-modulatory hierarchy between nitric oxide (NO) and noradrenaline (NA) in Xenopus laevis tadpoles. NO and NA have similar effects on fictive swimming; both potentiate glycinergic inhibition to slow swimming frequency and GABAergic inhibition to reduce episode durations. In addition, both modulators have direct effects on the membrane properties of motor neurons. Here we report that antagonism of noradrenergic pathways with phentolamine dramatically influences the effect of the NO donor S-nitroso-N-acetylpenicillamine (SNAP) on swimming frequency, but not its effect on episode durations. In contrast, scavenging extracellular NO with 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide(PTIO) does not influence any of the effects of NA on fictive swimming. These data place NO above NA in the metamodulatory hierarchy, strongly suggesting that NO works via a noradrenergic pathway to control glycine release but directly promotes GABA release. We confirmed this possibility using intracellular recordings from motor neurons. In support of a natural role for NO in the Xenopus locomotor network, PTIO not only antagonized all of the effects of SNAP on swimming but also, when applied on its own, modulated both swimming frequency and episode durations in addition to the underlying glycinergic and GABAergic pathways. Collectively, our results illustrate that NO and NA have parallel effects on motor neuron membrane properties and GABAergic inhibition, but that NO serially metamodulates glycinergic inhibition via NA.Publisher PDFPeer reviewe