This whitepaper focuses on the astrophysical systematics which are encountered in dark matter searches. Oftentimes in indirect and also in direct dark matter searches, astrophysical systematics are a major limiting factor to sensitivity to dark matter. Just as there are many forms of dark matter searches, there are many forms of backgrounds. We attempt to cover the major systematics arising in dark matter searches using photons -- radio and gamma rays -- to cosmic rays, neutrinos and gravitational waves. Examples include astrophysical sources of cosmic messengers and their interactions which can mimic dark matter signatures. In turn, these depend on commensurate studies in understanding the cosmic environment -- gas distributions, magnetic field configurations -- as well as relevant nuclear astrophysics. We also cover the astrophysics governing celestial bodies and galaxies used to probe dark matter, from black holes to dwarf galaxies. Finally, we cover astrophysical backgrounds related to probing the dark matter distribution and kinematics, which impact a wide range of dark matter studies. In the future, the rise of multi-messenger astronomy, and novel analysis methods to exploit it for dark matter, will offer various strategic ways to continue to enhance our understanding of astrophysical backgrounds to deliver improved sensitivity to dark matter.
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Abstract Objectives A number of studies have demonstrated the ontogenetic plasticity of long bone diaphyseal structure in response to mechanical loading. Captivity should affect mechanical loading of the limbs, but whether captive apes grow differently than wild apes has been debated. Here, we compare captive and wild juvenile and adult
Gorilla to ascertain whether growth trajectories in cross‐sectional diaphyseal shape are similar in the two environments.Materials and methods A sample of young juvenile (
n = 4) and adult (n = 10) captiveGorilla gorilla gorillaG.g. gorilla (n = 62) andG. beringei beringei (n = 75) in relative anteroposterior to mediolateral bending strength of the femur, tibia, and humerus. Cross sections were obtained using peripheral quantitative CT.Results Captive and wild adult
G.g. gorilla differed in bending strength ratios for all three bones, but these differences were not present in young juvenileG.g. gorilla . In comparisons across taxa, captive juvenileG.g. gorilla were more similar to wildG.g. gorilla than toG.b. beringei , while captive adultG.g. gorilla were more similar in shape toG.b. beringei in the hind limb.Discussion Captive and wild
G. gorilla -
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Abstract Objectives The effects of phylogeny and locomotor behavior on long bone structural proportions are assessed through comparisons between adult and ontogenetic samples of extant gorillas.
Materials and Methods A total of 281 wild‐collected individuals were included in the study, divided into four groups that vary taxonomically and ecologically: western lowland gorillas (
G. g. gorilla ), lowland and highland grauer gorillas(G. b. graueri ), and Virunga mountain gorillas (G. b. beringei ). Lengths and articular breadths of the major long bones (except the fibula) were measured, and diaphyseal cross‐sectional geometric properties determined using computed tomography. Ages of immature specimens (n = 145) were known or estimated from dental development. Differences between groups in hind limb to forelimb proportions were assessed in both adults and during development.Results Diaphyseal strength proportions among adults vary in parallel with behavioral/ecological differences, and not phylogeny. The more arboreal western lowland and lowland grauer gorillas have relatively stronger forelimbs than the more terrestrial Virunga mountain gorillas, while the behaviorally intermediate highland grauer gorillas have intermediate proportions. Diaphyseal strength proportions are similar in young infants but diverge after 2 years of age in western lowland and mountain gorillas, at the same time that changes in locomotor behavior occur. There are no differences between groups in length or articular proportions among either adults or immature individuals.
Conclusion Long bone diaphyseal strength proportions in gorillas are developmentally plastic, reflecting behavior, while length and articular proportions are much more genetically canalized. These findings have implications for interpreting morphological variation among fossil taxa.
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