Chalk Talks

2017 May 04

Bishnu Bastakoti (Perez-Mercader Group) "Chemical Synthesis and Spontaneous Formation of Giant Polymer Vesicles"

9:00am to 10:00am

Location: 

Naito Laboratory (Room 205), 12 Oxford Street

Abstract:

 

Polymer vesicles (polymersomes) are a synthetic analogue of liposomes. Block copolymers that mimic the lipid amphiphilicity can self-assemble into nano/micro sized polymer vesicles. Physicochemical properties of polymer vesicles such as stability, fluidity, permeability can be easily tuned due to the rich chemistry of block copolymers. In this talk, I will discuss the facile one pot synthesis of polymeric vesicles made of amphiphilic diblock copolymers through light mediated polymerization induced self-assembly and their potential applications. The growth of Read more about Bishnu Bastakoti (Perez-Mercader Group) "Chemical Synthesis and Spontaneous Formation of Giant Polymer Vesicles"

2017 Feb 02

Sukrit Ranjan (Sasselov Group) "The UV Surface Environment on Young Planets: Implications for Prebiotic Chemistry & Life on Other Worlds"

9:00am to 10:00am

Location: 

Naito Laboratory, Room 205, 12 Oxford Street

 

Abstract:  

Understanding the origin of life (abiogenesis) on Earth is key to understanding how it might start elsewhere. Recent laboratory studies suggest UV light may have played a critical role in the synthesis of molecules relevant to abiogenesis (prebiotic chemistry), such as RNA. I show that UV light interacts with prebiotic chemistry in ways that may be sensitive to the spectral shape and overall amplitude of irradiation. I use radiative transfer models to constrain the UV environment on early Earth (3.9 Ga). I find that the surface UV is insensitive Read more about Sukrit Ranjan (Sasselov Group) "The UV Surface Environment on Young Planets: Implications for Prebiotic Chemistry & Life on Other Worlds"

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.   However, recent measurements in our laboratory and in the literature appear to contradict this assumption, indicating that significant questions remain regarding the mechanistic Read more about "Understanding isotopic records of global carbon cycling" Elise Wilkes (Pearson Group)

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. Nucleic acid-based informational polymers (IPs) are even more likely for any life that may exist or may have once existed on Read more about Origins Chalk Talk Chris Carr (Ruvkun Group) "On the Search for Informational Polymers Beyond Earth"

2016 Nov 03

Origins Chalk Talk Raphaëlle Haywood (Charbonneau Group) "Breaking the ultimate barrier to characterising other Earths"

9:00am

Location: 

Natio Laboratory, Room 205, 12 Oxford Street

Abstract

The recent Kepler mission discovered thousands of new worlds beyond our Solar System, hundreds of which may be terrestrial planets of similar size to our Earth. The mass of a planet is arguably its most fundamental physical parameter; it dictates its internal composition and structure, and its ability to have an atmosphere, an essential component for a potentially life-hosting planet. In an era of large telescopes and high-precision instruments, the ultimate challenge to determining the masses of small, rocky exoplanets lies not in our technological Read more about Origins Chalk Talk Raphaëlle Haywood (Charbonneau Group) "Breaking the ultimate barrier to characterising other Earths"
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. It is particularly difficult to reconcile (sometimes cryptic) fossil morphology on one hand, and genetic composition and diversification over time on the other, when so little about the behavior of ancestral organisms can be Read more about Origins Chalk Talk -The Beagle in a Flask: Accessing artifacts of life’s evolutionary history through ancient-modern hybrid organisms - Betül Kaçar - OEB

2016 Apr 07

Origins Chalk Talk- Inorganic Chemistry does logic and computes- Marta Dueñas (EPS- Pérez-Mercader Group)

9:00am

Location: 

Naito Laboratory, Room 205, 12 Oxford St, Cambridge

Abstract - 

Information processing is fundamental to life: metabolism, replication, evolution, etc all rely on it. Extant living systems carry out information processing chemically, using biochemistry. Chemistry-based computation is key to the information processing taking place in life. The most powerful, and yet simple, known construct in computation is the Turing machine. It consists of a finite state machine capable of giving unique responses to inputs from an infinite tape on which it can also write and erase. A Turing machine emulates a mathematician carrying out a mechanical Read more about Origins Chalk Talk- Inorganic Chemistry does logic and computes- Marta Dueñas (EPS- Pérez-Mercader Group)

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

2016 Feb 04

Origins Chalk Talk - Understanding the Nearby Small Stars as Hosts of Planetary Systems - Jason Dittman (Astronomy- Charbonneau Group)

9:00am

Location: 

Naito Laboratory, Room 205, 12 Oxford Street, Cambridge

Abstract:

The nearby low-mass stars are the best candidate hosts for searching for transiting exoplanets to enable future characterization of their atmospheres. Unfortunately, our understanding of exoplanets is most often limited by our ability to characterize the host star. In this talk, I will focus on this stellar characterization problem, and how the MEarth transit survey has enabled us to better understand these stars. MEarth consists of 2 arrays of 8 telescopes each, one located at Mt. Hopkins, Arizona, and the other at Cerro Tololo, Chile. First, I used data from the Northern Read more about Origins Chalk Talk - Understanding the Nearby Small Stars as Hosts of Planetary Systems - Jason Dittman (Astronomy- Charbonneau Group)

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. The combination of spatial resolution and magnetic sensitivity of our Read more about Origins Chalk Talk - David Glenn (Physics - Walsworth Group)

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. Hypotheses for these observations include enhanced ammonium recycling and redox control on the Read more about Origins Chalk Talk - Gregory Henkes (EPS-Pearson Group) - Biomarkers from photosynthetic organisms as geologic recorders of ocean biogeochemistry

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