We made 28 collections of black flies (Diptera: Simuliidae) at 24 locations in central and northeastern Washington state, United States of America, and identified 10 species in three genera, including Simulium arcticum Malloch, which we studied cytogenetically. We analysed 745 larvae of S. arcticum cytogenetically from nine of the 11 sites where it occurred; five sites had small sample sizes. For the collections with large sample sizes, the distribution of S. arcticum may have a geographic pattern. Larvae in western tributaries of the Columbia River have the sex-linked IIL-2 inversion and heterozygotes for the IS-1 autosomal polymorphism in abundance but lack the IIL-21 sex-linked inversion, whereas larvae in eastern tributaries of the Columbia River possess the IIL-21 inversion but lack IIL-2 and the IS-1 inversions. A cytotype new to science, S. arcticum IIL-81, occurs in some larvae at the Methow River in the eastern Cascades region. All females, regardless of location, possess enhanced (Ce Ce) centromere bands in their IIL-chromosomes, whereas all males possess the enhanced, thin (Ce Ct) centromere band dimorphism. The Methow River had nine types of chromosomally identified males in 2019 and eight types in 2020.

The Rapid ASKAP Continuum Survey (RACS) is the first large-area survey to be conducted with the full 36-antenna Australian Square Kilometre Array Pathfinder (ASKAP) telescope. RACS will provide a shallow model of the ASKAP sky that will aid the calibration of future deep ASKAP surveys. RACS will cover the whole sky visible from the ASKAP site in Western Australia and will cover the full ASKAP band of 700–1800 MHz. The RACS images are generally deeper than the existing NRAO VLA Sky Survey and Sydney University Molonglo Sky Survey radio surveys and have better spatial resolution. All RACS survey products will be public, including radio images (with $\sim$ 15 arcsec resolution) and catalogues of about three million source components with spectral index and polarisation information. In this paper, we present a description of the RACS survey and the first data release of 903 images covering the sky south of declination $+41^\circ$ made over a 288-MHz band centred at 887.5 MHz.

We made 37 collections and analysed the polytene chromosomes of salivary glands of 726 larvae of the Simulium arcticum Malloch (Diptera: Simuliidae) complex from 10 locations in an unstudied region from central Idaho and southeastern Washington, United States of America. We compared our results to previous population cytotaxonomic research on larvae of this complex from western Montana, northern Idaho, and eastern Washington, United States of America. We identified four sibling species, S. brevicercum Knowlton and Rowe, S. saxosum Adler, S. arcticum sensu stricto, S. apricarium Adler, Currie, and Wood; and three cytotypes, S. arcticum IIL-9, IIL-17, and IIL-79, previously described by us. We discovered a new cytotype, S. arcticum IIL-80, at three locations in the western region of our sample area. We also found combinational (ancestral) types between S. saxosum and S. arcticum sensu stricto and between S. saxosum and S. arcticum IIL-79, suggesting that ancestral populations of the complex still exist. Geographic structuring of these sibling species and cytotypes are documented given that S. saxosum occurred in western regions, S. arcticum IIL-79 in northeastern regions, and S. apricarium in southeastern regions of our study area.

Neurodegerative disorders affect millions of people worldwide. Neural cells derived from human embryonic stem cells (hESC) have the potential for cell therapies and/or compound screening for treating affected individuals. While both protein and gene expression indicative of a neural phenotype has been exhibited in these differentiated cells, ultrastuctural studies thus far have been lacking. The objective of this study was to correlate hESC to neural differentiation culture conditions with ultrastructural changes observed in the treated cells. We demonstrate here that in basic culture conditions without growth factors or serum we obtain neural morphology. The addition of brain-derived neurotrophic factor (BDNF) and serum to cultures resulted in more robust neural differentiation. In addition to providing cues such as cell survival or lineage specification, additional factors also altered the intracellular structures and cell morphologies. Even though the addition of BDNF and serum did not increase synaptic formation, altered cellular structures such as abundant polyribosomes and more developed endoplasmic reticulum indicate a potential increase in protein production.

One conventional method for picking up ultrathin sections for transmission electron microscopy (TEM) is to prepare the mesh or slot grids with a formvar support film and then pick up your sections as they are floating in the knife boat. An alternative method is to first pick up sections on a naked grid and then lay them down on formvar film suspended over holes drilled in an aluminum bridge. I use this method when picking up serial sections on slot grids. A description of the method follows. The bridges I have were manufactured at the University of Georgia instrumentation Shop. They can also be purchased pre-made (for example, from SPI, Inc. They list them as Domino Racks), or one can make them from aluminum with a vise and drill. The sample bridge in the figure is similar to what I use. It is 5 cm long, 2.5 cm wide.