לוח שנה משולב

This talk will present the insights gained from 20 years of radiocarbon dating sculpture of the Dayak tribes of Borneo. These results include some revolutionary early dates, which require asking, “Who carved these works of art?” Archeology, linguistics, and DNA will be discussed in relation to the theory of a great Austronesian sea migration, 5000-2500 BC (or earlier), an idea that explains the Malayo- Polynesian language stretching from Madagascar to Easter Island, inclusive of Borneo, with shared Neolithic cultural features, like headhunting and tattooing. Later Bronze Age, Indian and Chinese influences will also be considered. The science of radiocarbon dating will be explained, with 30 Dayak sculptures clustered by age and style. A sequence of five dating periods from Archaic 200 BC to Post Classic 1950 AD will be postulated. We conclude that it is good to challenge the power and authority of conventional "art experts,” their folly of dating all Dayak sculptures as late 19th/early 20th Century being a prime example. So too, science also has its limitations. Ultimately, aesthetics and authenticity must be our primary concerns.

Abstract: A recent direction in dark matter phenomenology has been to consider multi-component dark matter, containing subsectors with interesting interactions and structure. These include models where part of dark matter is dissipative. In these particular models, the dissipative subsector will cool to form a dark matter disk, whose size, density, and temperature can be predicted from the parameters of the model. I will discuss details of the model and of the disk formation process, as well as various observational constraints and possible evidence for such a disk. I will also discuss potential astrophysical constraints from recent Gaia data, and under what assumptions these constraints should be taken seriously.

Nature provides an excellent source of inspiration for optical and mechanical materials.
In this talk, I will discuss opto-mechanical structures with nano scale precision.
In particular, I will show our recent results on micro/nano robotic elements that use light as source of energy and that are controlled by light as well.

Surface force experiments by the Perkin group suggest that the Debye screening length in aqueous solutions is not monotonic in electrolyte concentration. I shall review the fundamentals of Debye-Huckel theory and discuss some possible scenarios to understand the experimental observations.