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Infrared, UV/VIS and Raman Spectroscopy of Comet Wild-2 Samples Returned by the Stardust Mission
Results from the preliminary examination of Stardust samples obtained using various spectroscopic methods will be presented
Planning and designing an integrated management of coastal hypoxia in the Emila Romagna region water (Northern Adriatic Sea)
Abstract The design of an integrated monitoring network useful for the early-warning, the management and mitigation of both the environmental and socio-economic costs of hypoxia/anoxia events in the Northern Adriatic coastal zone, south of the mouth of the Po river, is described in the contribute. It has been developed within the EMMA research project (Environmental Management through Monitoring and Modelling of Anoxia; LIFE04ENV/IT/0479) (2004-2007). Over the past few decades, hypoxia events have recurrently affected the coastal zone of Emilia Romagna Region (Italy). Data collected by the C.Z. lying in the Province of Rimini, because of its economic importance, are presented. The area is subjected to intense anthropogenic pressure due to its high population (416 000 equivalent inhabitants) with tourist seasonal peaks of up to 973 110 equivalent inhabitants (in summer time), to industrial and agricultural activity, to maritime traffic and nutrient river discharges (about 600 tons y-1 of nitrogen and 300 tons y-1 of phosphorus, in 2002). Hypoxia and anoxia have a negative effect on the quality of bathing waters as well as on fishing and mussel farming, which are important activities for the economy of the area. The planning of the monitoring network has been carried out by analyzing the scientific knowledge on hypoxia in the local area; its integration with other existing monitoring activities, available facilities and data resources was considered in order to optimize cost effectiveness of the network
Stardust Interstellar Preliminary Examination (ISPE)
In January 2006 the Stardust sample return capsule returned to Earth bearing the first solid samples from a primitive solar system body, C omet 81P/Wild2, and a collector dedicated to the capture and return o f contemporary interstellar dust. Both collectors were approximately 0.1m(exp 2) in area and were composed of aerogel tiles (85% of the co llecting area) and aluminum foils. The Stardust Interstellar Dust Col lector (SIDC) was exposed to the interstellar dust stream for a total exposure factor of 20 m(exp 2-) day during two periods before the co metary encounter. The Stardust Interstellar Preliminary Examination ( ISPE) is a three-year effort to characterize the collection using no ndestructive techniques. The ISPE consists of six interdependent proj ects: (1) Candidate identification through automated digital microsco py and a massively distributed, calibrated search (2) Candidate extr action and photodocumentation (3) Characterization of candidates thro ugh synchrotronbased FourierTranform Infrared Spectroscopy (FTIR), S canning XRay Fluoresence Microscopy (SXRF), and Scanning Transmission Xray Microscopy (STXM) (4) Search for and analysis of craters in f oils through FESEM scanning, Auger Spectroscopy and synchrotronbased Photoemission Electron Microscopy (PEEM) (5) Modeling of interstell ar dust transport in the solar system (6) Laboratory simulations of h ypervelocity dust impacts into the collecting medi
Cryptotomography: reconstructing 3D Fourier intensities from randomly oriented single-shot diffraction patterns
We reconstructed the 3D Fourier intensity distribution of mono-disperse
prolate nano-particles using single-shot 2D coherent diffraction patterns
collected at DESY's FLASH facility when a bright, coherent, ultrafast X-ray
pulse intercepted individual particles of random, unmeasured orientations. This
first experimental demonstration of cryptotomography extended the
Expansion-Maximization-Compression (EMC) framework to accommodate unmeasured
fluctuations in photon fluence and loss of data due to saturation or background
scatter. This work is an important step towards realizing single-shot
diffraction imaging of single biomolecules.Comment: 4 pages, 4 figure
Extreme timescale core-level spectroscopy with tailored XUV pulses
A new approach for few-femtosecond time-resolved photoelectron spectroscopy
in condensed matter that balances the combined needs for both temporal and
energy resolution is demonstrated. Here, the method is designed to investigate
a prototypical Mott insulator, tantalum disulphide (1T-TaS2), which transforms
from its charge-density-wave ordered Mott insulating state to a conducting
state in a matter of femtoseconds. The signature to be observed through the
phase transition is a charge-density-wave induced splitting of the Ta 4f
core-levels, which can be resolved with sub-eV spectral resolution. Combining
this spectral resolution with few-femtosecond time resolution enables the
collapse of the charge ordered Mott state to be clocked. Precise knowledge of
the sub-20-femtosecond dynamics will provide new insight into the physical
mechanism behind the collapse and may reveal Mott physics on the timescale of
electronic hopping.Comment: 20 pages, 6 figure
Femtosecond x-ray diffraction from an aerosolized beam of protein nanocrystals
We demonstrate near-atomic-resolution Bragg diffraction from aerosolized
single granulovirus crystals using an x-ray free-electron laser. The form of
the aerosol injector is nearly identical to conventional liquid-microjet
nozzles, but the x-ray-scattering background is reduced by several orders of
magnitude by the use of helium carrier gas rather than liquid. This approach
provides a route to study the weak diffuse or lattice-transform signal arising
from small crystals. The high speed of the particles is particularly well
suited to upcoming MHz-repetition-rate x-ray free-electron lasers
Constraints on the Interstellar Dust Flux Based on Stardust at Home Search Results
Recent advances in active particle selection in the Heidelberg Van de r Graaf (VdG) dust accelerator have led to high-fidelity, low-backgro und calibrations of track sizes in aerogel as a function of particle size and velocity in the difficult regime above 10 km sec..1 and sub micron sizes. To the extent that the VdG shots are analogs for inters tellar dust (ISD) impacts, these new measurements enable us to place preliminary constraints on the ISD flux based on Stardust@home data
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