In X-ray crystallography, a difference density map shows the spatial distribution of the difference between the measured electron density of the crystal and the electron density explained by the current model.
Conventionally, they are displayed as isosurfaces with positive density—electron density where there's nothing in the model, usually corresponding to some constituent of the crystal that hasn't been modelled, for example a ligand or a crystallisation adjutant -- in green, and negative density—parts of the model not backed up by electron density, indicating either that an atom has been disordered by radiation damage or that it is modelled in the wrong place—in red.
Difference density maps are usually calculated using Fourier coefficients which are the differences between the observed structure factor amplitudes from the X-ray diffraction experiment and the calculated structure factor amplitudes from the current model, using the phase from the model for both terms (since no phases are available for the observed data). The two sets of structure factors must be on the same scale. It is now normal to also include weighting terms which take into account the estimated errors in the current model:
It’s density and surprisingly perhaps its composition changes as solar activity waxes and wanes ... Using data from ground based stations, engineers can create real time maps of the ionospheric density ... Mapping the ionosphere with millions of phones .
... interference contrast (OI-DIC) microscopy system combined with a confocal laser scanning microscope capable of precisely mapping optical path differences and estimating molecular densities.
The MasterLand Use Plan/GrowthManagement Plan is a map that describes general locations appropriate for different land uses, such as agriculture and low-density residential uses, and it designates an urbanizing area for more intensive mixed uses.
But to keep the plans from merely gathering dust, the state also requires cities to turn key components of the plan into law, including by re-drawing their zoning map, which dictates the density of different neighborhoods.
And the reason it varies, is because there are rocks of different density in the subsurface. So one of the tools that my geophysical colleagues have to map the subsurface is by measuring very precisely gravity ... We use lots of different techniques.
Current research explores density map estimation methods to overcome these limitations ... In conclusion, MLAENet represents a breakthrough in maize tassel counting, providing high-quality density maps and robust performance across different scenarios.
... densities, such as explosives or narcotics ... For example, in medical imaging, color mapping can be used to indicate different tissue densities or highlight areas of concern within the X-ray image.
The fire was mapped at 397 acres and 38 personnel remained on site ... The map shows wildfires, newly reported fires, and prescribed fires, areas of smoke with differing densities, red flag warnings and fire weather watches.
Since rocks and liquids within the Earth are of different densities, the waves move through them at different speeds, allowing geologists to figure out what type of material the waves are going through.
Since rocks and liquids within the Earth are of different densities, the waves move through them at different speeds, allowing geologists to figure out what type of material the waves are going through.
The difference was noticeable, even on the same block ...The Tree Equity Score map includes different canopy goals for different areas based on these kinds of factors ... an analysis of tree equity maps (NYT) A parting shot.
Since rocks and liquids within the Earth are of different densities, the waves move through them at different speeds, allowing geologists to figure out what type of material the waves are going through.
It's covered in lumps and bumps, with geology of varying density yanking on nearby masses with subtly differing degrees of force in an undulating map known as a geoid ... ....
They then put where those signatures came from into a density map with pins, which was provided to the Star-Tribune ... A density map showing where signatures from a petition drive organized by Preserve Our CodyNeighborhoods came from.
The team used a technique called in-vitro receptor autoradiography to map the density of receptors from six different neurotransmitter systems in over 100 brain regions ... Creating openly-accessible maps ...
Billings Gazette
26 Jun 2023
Billings Gazette
26 Jun 2023