Informal carers' experiences in everyday life and the use of digital assistive technology for time management in persons with dementia or mild cognitive impairment.

BACKGROUND: Digital assistive technology (DAT) may support time management in people with dementia or mild cognitive impairment (MCI), but research on DAT for time management is limited. We aimed to explore how everyday could be supported by DAT for time management in persons with dementia or MCI from informal carers' perspectives. This study focused on a DAT device for time management called MEMOplanner (MMP). METHOD: Using a mixed-methods design, we utilized the Time-Proxy© questionnaire and a study-specific interview guide to investigate the perspectives of informal carers (n = 8) regarding the use of MMP by individuals with dementia or MCI. RESULT: The MMP was helpful in keeping track of time and activity. It helped to maintain an active lifestyle and facilitated communication. However, the MMP did not reduce the need for assistance from the informal carers, and it took time to learn the different functions of the device. Further research into employing a more extensive array of DAT for time management or other areas to assist individuals with dementia will yield valuable insights into enhancing and sustaining a higher quality of life despite cognitive decline.

Observation of Light Thermalization to Negative-Temperature Rayleigh-Jeans Equilibrium States in Multimode Optical Fibers.

Although the temperature of a thermodynamic system is usually believed to be a positive quantity, under particular conditions, negative-temperature equilibrium states are also possible. Negative-temperature equilibriums have been observed with spin systems, cold atoms in optical lattices, and two-dimensional quantum superfluids. Here we report the observation of Rayleigh-Jeans thermalization of light waves to negative-temperature equilibrium states. The optical wave relaxes to the equilibrium state through its propagation in a multimode optical fiber-i.e., in a conservative Hamiltonian system. The bounded energy spectrum of the optical fiber enables negative-temperature equilibriums with high energy levels (high-order fiber modes) more populated than low energy levels (low-order modes). Our experiments show that negative-temperature speckle beams are featured, in average, by a nonmonotonic radial intensity profile. The experimental results are in quantitative agreement with the Rayleigh-Jeans theory without free parameters. Bringing negative temperatures to the field of optics opens the door to the investigation of fundamental issues of negative-temperature states in a flexible experimental environment.

Classical Rayleigh-Jeans Condensation of Light Waves: Observation and Thermodynamic Characterization.

Theoretical studies on wave turbulence predict that a purely classical system of random waves can exhibit a process of condensation, which originates in the singularity of the Rayleigh-Jeans equilibrium distribution. We report the experimental observation of the transition to condensation of classical optical waves propagating in a multimode fiber, i.e., in a conservative Hamiltonian system without thermal heat bath. In contrast to conventional self-organization processes featured by the nonequilibrium formation of nonlinear coherent structures (solitons, vortices,…), here the self-organization originates in the equilibrium Rayleigh-Jeans statistics of classical waves. The experimental results show that the chemical potential reaches the lowest energy level at the transition to condensation, which leads to the macroscopic population of the fundamental mode of the optical fiber. The near-field and far-field measurements of the condensate fraction across the transition to condensation are in quantitative agreement with the Rayleigh-Jeans theory. The thermodynamics of classical wave condensation reveals that the heat capacity takes a constant value in the condensed state and tends to vanish above the transition in the normal state. Our experiments provide the first demonstration of a coherent phenomenon of self-organization that is exclusively driven by optical thermalization toward the Rayleigh-Jeans equilibrium.