Chalk Talks

2017 Apr 06

"Understanding isotopic records of global carbon cycling" Elise Wilkes (Pearson Group)

9:00am to 10:00am

Location: 

Natio Laboratory, Room 205, 12 Oxford Street

Abstract: The carbon isotopic composition of algal organic matter preserved in marine sediments provides a window into the evolution of the global carbon cycle through geologic time, including variations in atmospheric CO2 levels. Traditional models for interpreting marine isotope records assume that these archives largely reflect kinetic isotopic discrimination by the carbon-fixing enzyme RubisCO.

2016 Dec 01

Origins Chalk Talk Chris Carr (Ruvkun Group) "On the Search for Informational Polymers Beyond Earth"

9:00am

Location: 

Natio Laboratory, Room 205, 12 Oxford Street

The building blocks of life as we know it, including amino acids, nucleobases, and sugars, were synthesized early in the history of the solar system in space, in processes likely common throughout the universe. After delivery to habitable worlds, such building blocks may have biased independent origins of life, if they occurred, towards similar solutions. For example, nucleic acids or their cousins may serve as a common physical basis for heritability and evolution.

2016 Oct 06

Origins Chalk Talk Consortium Student Panel "2016 JPL Trip"

9:00am

Location: 

Natio Laboratory, Room 205, 12 Oxford Street

This Chalk Talk will be a panel discussion of Origins Graduate Consortium student members, moderated by Dimitar Sasselov, as they share their assessment of the Consortium’s first field trip, a five-day trip to Pasadena, California in June 2016.  Visits to the Jet Propulsion Laboratory, Mount Wilson, the Giant Magellan Telescope headquarters, and CalTech focused on astrobiology and exoplanet searches and characterization. 

2016 May 05

Origins Chalk Talk -The Beagle in a Flask: Accessing artifacts of life’s evolutionary history through ancient-modern hybrid organisms - Betül Kaçar - OEB

9:00am

Location: 

Naito Laboratory, Room 205, 12 Oxford St, Cambridge

Abstract - Our living world is the result of a complex history spanning billions of years. Scientists have access to artifacts of this history, namely the fossil record and the genomes of many different living organisms. But there are surprisingly limited means with which to infer critical evolutionary elements in the deep past that resulted in modern biota.

2016 Mar 03

Origins Chalk Talk -A Statistical Mechanical Description of Nonenzymatic Replication- Albert Fahrenbach (MGH - Szostak Lab)

9:00am

Location: 

Naito Laboratory, Room 205, 12 Oxford St, Cambridge

Abstract- I will attempt to give an overview of some basic principles involved in nonenzymatic (RNA) replication using the language of statistical mechanics.  I will give a mathematical definition of fidelity in terms of thermodynamic and kinetic constants,  and try to demonstrate the connection between entropy and the transmission of information in this context.  My main goal is to try to convey a general idea of nonenzymatic replication using the language of physics, rather than specific chemical structures, in an effort to gives those non-chemists/biologists in the room a description …

2015 Dec 03

Origins Chalk Talk "A Simple Analytical Model for Rocky Planet Interior" Li Zeng (EPS- Jacobsen Group)

9:00am

Location: 

Naito Laboratory, Room 205, 12 Oxford St, Cambridge

Abstract:
From PREM (Dziewonski & Anderson 1981), I deduce a simple analytical model for rocky planets. Tested with PREM-extrapolated numerical models (Zeng, Sasselov, Jacobsen 2015), this model can be applied to any two-layer (iron-silicate) rocky exoplanets with CMF (core mass fraction) range 0.2∼0.35 and mass range of 0.1~20 M⊕. This analytical model yields several handy and powerful formulae for the interior of such a planet. They can provide physical insights into the planet structure. 

2015 Nov 05

Origins Chalk Talk - David Glenn (Physics - Walsworth Group)

9:00am

Location: 

Naito Laboratory, Room 205, 12 Oxford St, Cambridge

Abstract: I will describe recent work on the development of a sensitive magnetic-field microscope with sub-micrometer spatial resolution. This instrument employs a layer of nitrogen-vacancy (NV) color centers at the surface of a diamond chip to enable imaging of magnetic fields from nearby samples. Together with collaborators in the MIT department of Earth, Atmospheric and Planetary Sciences, we have used the NV-diamond microscope to study distributions of magnetic minerals in a variety of terrestrial and meteoric rocks.

2015 Oct 01

Origins Chalk Talk - Gregory Henkes (EPS-Pearson Group) - Biomarkers from photosynthetic organisms as geologic recorders of ocean biogeochemistry

9:00am

Location: 

Naito Laboratory, Room 205, 12 Oxford St, Cambridge

Abstract: Organic molecules preserved in sedimentary rocks are generally regarded as robust recorders of the biology and chemistry of ancient environments. Here I will outline our recent efforts to extract, quantify, and measure the isotopic composition of compounds derived from chlorophyll molecules in organic-rich rocks. Their nitrogen stable isotope compositions are of particular interest because they record fingerprints of ancient ocean biogeochemistry that are not found in modern seas.

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