This is especially true for long lasting eruptions when ash fallout will occur repetitively over weeks or months, for volcanic regions which are less accessible and for more distal and thin ash layers that are poorly preserved over more than a season.
Scientists analyzing fragments of poorly preserved dinosaur bones excavated more than a century ago have discovered what appear to be red blood cells and collagen fibers, soft tissues that thus far have only found rarely, on extremely well-preserved fossils.
Not much rock art survives in western Africa, and in eastern and central parts of the continent more recent but still invaluable paintings have been poorly preserved.But there is progress.
This fact probably has a negligible effect to the overall biological conclusions but suggests that families showing poorly preserved pattern 3 motifs may enclose more protein isoforms, which should be characterized by separate HMMs and logos to clarify all possible pattern 3 variants.
The team has also dug up the likely remains of peasants, probably dating from the 11th century two poorly preserved skeletons found outside the wall and they're hoping for more.
Since his death, McCay's original artwork has been poorly preserved; much was destroyed in a late-1930s house fire, and more was sold off when the McCays needed money.
Of these, 36 were well-preserved, 48 were in a fair condition and 46 were poorly preserved.
Spices preserve, and they also make the poorly preserved palatable, masking the appetite-killing stench of decay.
Even a poorly preserved brain, they reasoned, might be able to undergo a kind of digital repair and rehabilitation.
