Two New Genera of Hemisarcoptidae (Acari: Astigmata) From the Huron Mountains of Northern Michigan

Two new genera and species of Hemisarcoptidae, Superioropus huronmontanus and Huronopus michiganensis are described from deutonymphs phoretic on ichneumonid wasps from the Huron Mountains, Marquette County, Michigan

Temperature and host effects on key morphological characters of Hemisarcoptes cooremani and Hemisarcoptes malus (Acari: Hemisarcoptidae)

We investigated the influence of temperature and resources on six morphological characters thought to distinguish two North American species of Hemisarcoptes (H. malus and H. cooremani ). We raised mites at three temperatures (15, 24 or 30°C) and on two different scale insect prey ( Aspidiotus nerii or Aonidiella aurantii ) which were cultured on two different substrates (potato tubers and lemon fruit). In general, the temperature had more of an influence on the character variation than did the host and the highest temperature resulted in the smallest mean body size. The two species did not respond to changes in the temperature or host in a symmetrical fashion. The temperature significantly influenced the lengths of the external scapular setae ( sce ) of H. malus and the sce and first coxal setae ( 1a ) of H. cooremani . The relative lengths of the setae sce and 1a of H. cooremani were significantly influenced by the temperature, while the host type significantly influenced the paraproctal setae ( ps 2 ). Major-axis regressions indicated that H. cooremani had an absolutely longer mean setal length for 1a and for ps 2 , than H. malus , but a relatively shorter sce . An ANOVA of the size-adjusted shield characters of H. malus resulted in non-significant effects of the temperature or host on either the prodorsal shield area or and area in H. cooremani . Regressions of the shield area (size) on body length, resulted in two clear groupings by species. Hemisarcoptes cooremani had an absolutely larger shield area and increased circumference (complexity), as compared to H. malus . A plot of the shield circumference in relation to the shield area, however, resulted in a single trajectory, indicating that shield complexity is an allometric consequence of an increase in body size in both species. Though characters can be influenced significantly by environmental parameters, the species-specific patterns of some characters of North American Hemisarcoptes are distinctive enough to allow diagnosis and identification.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/41782/1/10493_2004_Article_BF00051552.pd

Coronal Heating as Determined by the Solar Flare Frequency Distribution Obtained by Aggregating Case Studies

Flare frequency distributions represent a key approach to addressing one of the largest problems in solar and stellar physics: determining the mechanism that counter-intuitively heats coronae to temperatures that are orders of magnitude hotter than the corresponding photospheres. It is widely accepted that the magnetic field is responsible for the heating, but there are two competing mechanisms that could explain it: nanoflares or Alfv\'en waves. To date, neither can be directly observed. Nanoflares are, by definition, extremely small, but their aggregate energy release could represent a substantial heating mechanism, presuming they are sufficiently abundant. One way to test this presumption is via the flare frequency distribution, which describes how often flares of various energies occur. If the slope of the power law fitting the flare frequency distribution is above a critical threshold, $\alpha=2$ as established in prior literature, then there should be a sufficient abundance of nanoflares to explain coronal heating. We performed $>$600 case studies of solar flares, made possible by an unprecedented number of data analysts via three semesters of an undergraduate physics laboratory course. This allowed us to include two crucial, but nontrivial, analysis methods: pre-flare baseline subtraction and computation of the flare energy, which requires determining flare start and stop times. We aggregated the results of these analyses into a statistical study to determine that $\alpha = 1.63 \pm 0.03$. This is below the critical threshold, suggesting that Alfv\'en waves are an important driver of coronal heating.Comment: 1,002 authors, 14 pages, 4 figures, 3 tables, published by The Astrophysical Journal on 2023-05-09, volume 948, page 7