Biophysics - Quantum path to photosynthesis

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/62904/1/446740a.pd

Phonon Raman spectra of colloidal CdTe nanocrystals: effect of size, non-stoichiometry and ligand exchange

Resonant Raman study reveals the noticeable effect of the ligand exchange on the nanocrystal (NC) surface onto the phonon spectra of colloidal CdTe NC of different size and composition. The oleic acid ligand exchange for pyridine ones was found to change noticeably the position and width of the longitudinal optical (LO) phonon mode, as well as its intensity ratio to overtones. The broad shoulder above the LO peak frequency was enhanced and sharpened after pyridine treatment, as well as with decreasing NC size. The low-frequency mode around 100 cm-1 which is commonly related with the disorder-activated acoustical phonons appears in smaller NCs but is not enhanced after pyridine treatment. Surprisingly, the feature at low-frequency shoulder of the LO peak, commonly assigned to the surface optical phonon mode, was not sensitive to ligand exchange and concomitant close packing of the NCs. An increased structural disorder on the NC surface, strain and modified electron-phonon coupling is discussed as the possible reason of the observed changes in the phonon spectrum of ligand-exchanged CdTe NCs

Molecular Genetic Reevaluation of the Dutch Hyperekplexia Family

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Col-OSSOS: Colours of the Outer Solar System Origins Survey

International audienceThe surfaces of trans-Neptunian objects (TNOs) are poorly understood. Other than the large objects which exhibit signatures of various ices, very little has been discerned about the compositions of most TNOs. In recent years, some concrete knowledge about the distribution of surface colours of small TNOs has come to light. It is now generally accepted that small TNOs fall into at least three classes of object based on their surface colours and albedo. TNO surface type is also correlated with dynamical class, with certain types of TNO being found primarily in certain regions of the outer Solar System. This correlation presents the intriguing idea that the surfaces of TNOs contain information on more than composition, but as well hold the key to understanding the dynamical processes that lead to the giant planets violently dispersing the protoplanetesimal disk and populating the Kuiper Belt region. It is around this idea that the Col-OSSOS survey is predicated. This 4 year program which started in 2014B is simultaneously using the Gemini-North and Canada-France-Hawaii telescopes to gather near simultaneous u, g, r, and J spectral photometry of all targets in the Outer Solar System Origins Survey (OSSOS) brighter than r’=23.5 (~140 expected). The focus of Col-OSSOS is completeness and consistency, with the same SNR=25 being reached in all bands, for all targets brighter than our depth limit.Col-OSSOS will provide a combined compositional-dynamical map from which key hypotheses about the Solar System's cosmogony can be tested. For example, by mapping the fraction of TNOs with cold-classical like surface colours, we will be able to determine how much of the belt was populated by dynamical scattering versus sweep-up from Neptune. Further, we will be able to constrain the compositional homogeneity of the protoplanetesimal disk. The surfaces of TNOs must reflect that homogeneity; a heterogeneous disk will result in a clumpy colour distribution with many unique types, while a homogeneous disk will result in a smooth distribution of colours with only a few distinct types. Here we will present preliminary results and report on the initial progress of the survey

Col-OSSOS: Colours of the Outer Solar System Origins Survey

International audienceThe surfaces of trans-Neptunian objects (TNOs) are poorly understood. Other than the large objects which exhibit signatures of various ices, very little has been discerned about the compositions of most TNOs. In recent years, some concrete knowledge about the distribution of surface colours of small TNOs has come to light. It is now generally accepted that small TNOs fall into at least three classes of object based on their surface colours and albedo. TNO surface type is also correlated with dynamical class, with certain types of TNO being found primarily in certain regions of the outer Solar System. This correlation presents the intriguing idea that the surfaces of TNOs contain information on more than composition, but as well hold the key to understanding the dynamical processes that lead to the giant planets violently dispersing the protoplanetesimal disk and populating the Kuiper Belt region. It is around this idea that the Col-OSSOS survey is predicated. This 4 year program which started in 2014B is simultaneously using the Gemini-North and Canada-France-Hawaii telescopes to gather near simultaneous u, g, r, and J spectral photometry of all targets in the Outer Solar System Origins Survey (OSSOS) brighter than r’=23.5 (~140 expected). The focus of Col-OSSOS is completeness and consistency, with the same SNR=25 being reached in all bands, for all targets brighter than our depth limit.Col-OSSOS will provide a combined compositional-dynamical map from which key hypotheses about the Solar System's cosmogony can be tested. For example, by mapping the fraction of TNOs with cold-classical like surface colours, we will be able to determine how much of the belt was populated by dynamical scattering versus sweep-up from Neptune. Further, we will be able to constrain the compositional homogeneity of the protoplanetesimal disk. The surfaces of TNOs must reflect that homogeneity; a heterogeneous disk will result in a clumpy colour distribution with many unique types, while a homogeneous disk will result in a smooth distribution of colours with only a few distinct types. Here we will present preliminary results and report on the initial progress of the survey

Col-OSSOS: Colours of the Outer Solar System Origins Survey

International audienceThe surfaces of trans-Neptunian objects (TNOs) are poorly understood. Other than the large objects which exhibit signatures of various ices, very little has been discerned about the compositions of most TNOs. In recent years, some concrete knowledge about the distribution of surface colours of small TNOs has come to light. It is now generally accepted that small TNOs fall into at least three classes of object based on their surface colours and albedo. TNO surface type is also correlated with dynamical class, with certain types of TNO being found primarily in certain regions of the outer Solar System. This correlation presents the intriguing idea that the surfaces of TNOs contain information on more than composition, but as well hold the key to understanding the dynamical processes that lead to the giant planets violently dispersing the protoplanetesimal disk and populating the Kuiper Belt region. It is around this idea that the Col-OSSOS survey is predicated. This 4 year program which started in 2014B is simultaneously using the Gemini-North and Canada-France-Hawaii telescopes to gather near simultaneous u, g, r, and J spectral photometry of all targets in the Outer Solar System Origins Survey (OSSOS) brighter than r’=23.5 (~140 expected). The focus of Col-OSSOS is completeness and consistency, with the same SNR=25 being reached in all bands, for all targets brighter than our depth limit.Col-OSSOS will provide a combined compositional-dynamical map from which key hypotheses about the Solar System's cosmogony can be tested. For example, by mapping the fraction of TNOs with cold-classical like surface colours, we will be able to determine how much of the belt was populated by dynamical scattering versus sweep-up from Neptune. Further, we will be able to constrain the compositional homogeneity of the protoplanetesimal disk. The surfaces of TNOs must reflect that homogeneity; a heterogeneous disk will result in a clumpy colour distribution with many unique types, while a homogeneous disk will result in a smooth distribution of colours with only a few distinct types. Here we will present preliminary results and report on the initial progress of the survey

Col-OSSOS: Colours of the Outer Solar System Origins Survey

International audienceThe surfaces of trans-Neptunian objects (TNOs) are poorly understood. Other than the large objects which exhibit signatures of various ices, very little has been discerned about the compositions of most TNOs. In recent years, some concrete knowledge about the distribution of surface colours of small TNOs has come to light. It is now generally accepted that small TNOs fall into at least three classes of object based on their surface colours and albedo. TNO surface type is also correlated with dynamical class, with certain types of TNO being found primarily in certain regions of the outer Solar System. This correlation presents the intriguing idea that the surfaces of TNOs contain information on more than composition, but as well hold the key to understanding the dynamical processes that lead to the giant planets violently dispersing the protoplanetesimal disk and populating the Kuiper Belt region. It is around this idea that the Col-OSSOS survey is predicated. This 4 year program which started in 2014B is simultaneously using the Gemini-North and Canada-France-Hawaii telescopes to gather near simultaneous u, g, r, and J spectral photometry of all targets in the Outer Solar System Origins Survey (OSSOS) brighter than r’=23.5 (~140 expected). The focus of Col-OSSOS is completeness and consistency, with the same SNR=25 being reached in all bands, for all targets brighter than our depth limit.Col-OSSOS will provide a combined compositional-dynamical map from which key hypotheses about the Solar System's cosmogony can be tested. For example, by mapping the fraction of TNOs with cold-classical like surface colours, we will be able to determine how much of the belt was populated by dynamical scattering versus sweep-up from Neptune. Further, we will be able to constrain the compositional homogeneity of the protoplanetesimal disk. The surfaces of TNOs must reflect that homogeneity; a heterogeneous disk will result in a clumpy colour distribution with many unique types, while a homogeneous disk will result in a smooth distribution of colours with only a few distinct types. Here we will present preliminary results and report on the initial progress of the survey

Lightcurve Studies of Trans-Neptunian Objects from the Outer Solar System Origins Survey using the Hyper Suprime-Camera

International audienceLightcurves can reveal information about the gravitational processes that have acted on small bodies since their formation and/or their gravitational history.At the extremes, lightcurves can provide constraints on the material properties and interior structure of individual objects.In large sets, lightcurves can possibly shed light on the source of small body populations that did not form in place (such as the dynamically excited trans-Neptunian Objects (TNOs)).We have used the sparsely sampled photometry from the well characterized Outer Solar System Origins Survey (OSSOS) discovery and recovery observations to identify TNOs with potentially large amplitude lightcurves.Large lightcurve amplitudes would indicate that the objects are likely elongated or in potentially interesting spin states; however, this would need to be confirmed with further follow-up observations.We here present the results of a 6-hour pilot study of a subset of 17 OSSOS objects using Hyper Suprime-Cam (HSC) on the Subaru Telescope.Subaru's large aperture and HSC's large field of view allows us to obtain measurements on multiple objects with a range of magnitudes in each telescope pointing.Photometry was carefully measusured using an elongated aperture method to account for the motion of the objects, producing the short but precise lightcurves that we present here.The OSSOS objects span a large range of sizes, from as large as several hundred kilometres to as small as a few tens of kilometres in diameter.We are thus investigating smaller objects than previous light-curve projects have typically studied