post-doc talks 10/20/14
Ashesh Dhawale, Ölveczky Lab
- “Role of subcortical circuits in motor skill learning”
Introduction
- Function of basal gangalion not well understood.
- conflicting annotations
- invovled in parkinsons, huntingtons
- ‘sequencing chuncking’
- organizes downstream circuits into groups (based on activity recording experiments).
- monkey can still learn sequences without BG. speed of choice is a bit slower.
Experiment
- two tap with in-between delay.
- initially the rat tends to tap too frequently, then eventualy strongly learns the tap interval. (takes 30 days to learn).
- need to first teach to tap once. get a beep to know reward has arrived. Computer program trains rats.
- dvelop whole series of additional movements
- don’t require motor cortex to learn this. Do require BG.
Experiment 2
- record from neurons. Film from 3 angles at high speed. Also have acceleratomoter.
- see specific neuron firin at particular events
- some cells fire in between task events very reliably.
- controls sequencing.
Charles Vidoudez, Girguis Lab
- “Deep Sea microorganisms, interactions with their environment, and the tools to study them “
- interest: micro-organism community environment interactions
- techniques: mass spec, metabolomics
intro: vents
- hot fluid, anoxic, low pH, hihg CH4, H2S CO2, all mixing. Organisms use gradient in redox between ocean and vent.
- muscles + symbiotic bacteria combine H2S and O2 and CH4 and O2 to produce energy.
experiment
- current sampling: sample size is limited, time delay is a problem.
- developed in situ mass spec — measure at site.
- can observe consumption of H2S and CH4. More mussels where H2S is more, more use of whatever is more present.
Temporal resolution
- now deployed long term sampling devices. sensors connected to internet via cables.
Ranga Dias, Lyman Lab – 1st physics talk!
- “Insulator-metal transitions in simple molecular solids”
- CS2 and super-conductivity.
- 10 GPA (human on a 1mm needle.
- oxygen metaziles at 60 GPA. becomes superconducting at 100 GPA
- system – squeeze sample between two diamonds (800 to 100 um)
- can generate pressures up to 350 GPa.
- resistivity measurement. Try under pressure: need small probes.
- Bridgeman (Nobel in ’46? for squeezing CS2 and solving the structure). CS3 at 20 GPA
- compressed to 51.2 GPA become metal like – shiny / reflective.
- resistivity drops 8 orders of magnitude when squeezed. Semiconductor in ‘black polymer’ regime. then metal.
- superconductor becomes a perfect diamagnet Completely repels a magnetic field, moves out of the field. (hence magnetic levitation) response (travel without resistance, conduct without resistance).
- Cool and have pressure (60 to 172 GPA) see superconductivity at 5-6 K. (high temp superconductor 150 K.
- Faraday quote to chancellor of UK: use of electricity: some-day you can tax it.
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