There were two viable theories of generation, preformation
and epigenesis, existing in the Seventeenth and
Eighteenth Centuries. Due to their irreconcilable nature,
they were often at loggerheads during this time interval.
The status of these generation theories can be effectively
understood in terms of Thomas Kuhn's conception of preparadigm
science....
p-type conducting films of α- BaCu₂S₂ have been deposited onto glass and KBr substrates, yielding a conductivity of 17 S/cm and a Hall mobility of 3.5 cm²/Vs. For a 430-nm-thick film, the optical transparency approaches 90% in the visible portion of the spectrum at 650 nm, and a transparency of...
In the Pacific Northwest, previous studies have found a negative effect of timber management on the abundance of stream amphibians, but results have been variable and region specific. These studies have generally used survey methods that did not account for differences in capture probability and focused on stands that were...
The increase in atmospheric concentrations of water vapor with global warming is a large positive feedback in the climate system. Thus, even relatively small errors in its magnitude can lead to large uncertainties in predicting climate response to anthropogenic forcing. This study incorporates observed variability of water vapor over 2002–2009...
Stream restorations that increase geomorphic stability can improve habitat quality, which should benefit selected species and local aquatic ecosystems. This assumption is often used to define primary restoration goals; yet, biological responses to restoration are rarely monitored or evaluated methodically. Macroinvertebrate communities were inventoried at 6 study reaches within 5...
Small, low-head diversion dams are capable of withdrawing much of the flow of a river, often resulting in elevated water temperatures. Accelerated growth and development of aquatic invertebrates has been demonstrated in warmer temperatures, suggesting that the timing of insect emergence and adult body size may be significantly altered by...
In some bacteria, cysteine is converted to cysteine sulfinic acid by cysteine dioxygenases (CDO) that are only ∼15–30% identical in sequence to mammalian CDOs. Among bacterial proteins having this range of sequence similarity to mammalian CDO are some that conserve an active site Arg residue (“Arg-type” enzymes) and some having...
The site-specific incorporation of non-canonical amino acids (ncAAs) into proteins is an important tool for understanding biological function. Traditionally, each new ncAA targeted requires a resource-consuming process of generating new ncAA aminoacyl tRNA synthetase/tRNACUA pairs. However, the discovery that some tRNA synthetases are “permissive,” in that they can incorporate multiple...
Ideal values of bond angles and lengths used as external restraints are crucial for the successful
refinement of protein crystal structures at all but the highest of resolutions. The restraints in
common usage today have been designed based on the assumption that each type of bond or
angle has a...