Publications by authors named "William Humphreys"

Understanding the profound influence of climatic and tectonic histories on adaptation and speciation is a crucial focus in biology research. While voyages like Humboldt's expedition shaped our understanding of adaptation, the origin of current biodiversity remains unclear - whether it arose in situ or through dispersal from analogous habitats. Situated in the geologically complex Australopacific region, our study focuses on Limbodessus diving beetles (Dytiscidae), a diverse genus distributed from underground aquifers in Western Australia to alpine meadows in New Guinea.

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Recent growth in space systems has seen increasing capabilities packed into smaller and lighter Earth observation and deep space mission spacecraft. Phase-change materials (PCMs) are nonvolatile, reconfigurable, fast-switching, and have recently shown a high degree of space radiation tolerance, thereby making them an attractive materials platform for spaceborne photonics applications. They promise robust, lightweight, and energy-efficient reconfigurable optical systems whose functions can be dynamically defined on-demand and on-orbit to deliver enhanced science or mission support in harsh environments on lean power budgets.

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The accurate diagnosis of portovascular anomalies has been facilitated by improvements in diagnostic imaging technology. In humans, hepatic arterial blood flow changes in response to the reduction in portal blood flow. The hepatic arterial buffer response characterizes an intrinsic regulatory mechanism in response to reduced portal venous blood flow, which results in hepatic arterial enlargement.

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Background: Viruses play important roles in modulating microbial communities and influencing global biogeochemistry. There is now growing interest in characterising their ecological roles across diverse biomes. However, little is known about viral ecology in low-nutrient, chemotrophic-based environments.

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Groundwater is a vital ecosystem of the global water cycle, hosting unique biodiversity and providing essential services to societies. Despite being the largest unfrozen freshwater resource, in a period of depletion by extraction and pollution, groundwater environments have been repeatedly overlooked in global biodiversity conservation agendas. Disregarding the importance of groundwater as an ecosystem ignores its critical role in preserving surface biomes.

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  • * In an investigation of subterranean isopods from Western Australia, seven endoglucanase genes were identified across both surface and cave species, suggesting these genes have been retained.
  • * Analysis indicates most cellulase genes are under purifying selection, showing they likely produce functional peptides, while some adaptations in subterranean lineages point to evolutionary changes linked to their unique environments and energy sources.
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Background: Anchialine environments, in which oceanic water mixes with freshwater in coastal aquifers, are characterised by stratified water columns with complex physicochemical profiles. These environments, also known as subterranean estuaries, support an abundance of endemic macro and microorganisms. There is now growing interest in characterising the metabolisms of anchialine microbial communities, which is essential for understanding how complex ecosystems are supported in extreme environments, and assessing their vulnerability to environmental change.

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  • Tropical cyclones (TCs) are influenced by the intertropical convergence zone (ITCZ), and understanding how TCs respond to changes in the ITCZ's position is crucial, especially in the Southern Hemisphere.
  • A new study analyzed a 1500-year record of ITCZ movements in tropical Australia to better understand the relationship between ITCZ shifts and TC activity in subtropical regions.
  • The findings indicate that as the ITCZ moves southward, it leads to increased rainfall from TCs in subtropical areas, suggesting that TCs could become more significant for moisture availability in Western Australia due to climate change.
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Subterranean habitats are generally very stable environments, and as such evolutionary transitions of organisms from surface to subterranean lifestyles may cause considerable shifts in physiology, particularly with respect to thermal tolerance. In this study we compared responses to heat shock at the molecular level in a geographically widespread, surface-dwelling water beetle to a congeneric subterranean species restricted to a single aquifer (Dytiscidae: Hydroporinae). The obligate subterranean beetle Paroster macrosturtensis is known to have a lower thermal tolerance compared to surface lineages (CT 38 °C cf.

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Thermal tolerance limits in animals are often thought to be related to temperature and thermal variation in their environment. Recently, there has been a focus on studying upper thermal limits due to the likelihood for climate change to expose more animals to higher temperatures and potentially extinction. Organisms living in underground environments experience reduced temperatures and thermal variation in comparison to species living in surface habitats, but how these impact their thermal tolerance limits are unclear.

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Objective: To compare the attenuation of the medial coronoid process (MCP) in dogs with and without arthroscopically confirmed evidence of medial coronoid disease (MCD).

Animals: The database at our institution was searched for cases with thoracic limb lameness, diagnosed with MCD by arthroscopic examination that had CT as part of their investigation and compared with a control group of elbow joints from cadavers euthanized for reasons unrelated to MCD. A total of 84 elbow joints were included that met these criteria.

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The suborder Gobioidei is among the most diverse groups of vertebrates, comprising about 2310 species. In the fossil record gobioids date back to the early Eocene (c. 50 m.

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In the framework of neutral theory of molecular evolution, genes specific to the development and function of eyes in subterranean animals living in permanent darkness are expected to evolve by relaxed selection, ultimately becoming pseudogenes. However, definitive empirical evidence for the role of neutral processes in the loss of vision over evolutionary time remains controversial. In previous studies, we characterized an assemblage of independently-evolved water beetle (Dytiscidae) species from a subterranean archipelago in Western Australia, where parallel vision and eye loss have occurred.

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Groundwater biota are crucial for the ecological functioning of subterranean ecosystems. However, while knowledge of the taxonomic diversity of groundwater invertebrates (stygofauna) is increasing, functional ecological information is still limited. Here, we investigate seldom empirically tested assumptions around stygofaunal trophic plasticity in coping with oligotrophic habitats.

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Objectives: To describe dye distribution and spinal nerve involvement after a simulated erector spinae plane (ESP) block performed on fresh equine cadavers.

Study Design: Experimental cadaver study.

Animals: A group of 11 adult equine cadavers.

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Groundwaters host vital resources playing a key role in the near future. Subterranean fauna and microbes are crucial in regulating organic cycles in environments characterized by low energy and scarce carbon availability. However, our knowledge about the functioning of groundwater ecosystems is limited, despite being increasingly exposed to anthropic impacts and climate change-related processes.

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Most subterranean animals are assumed to have evolved from surface ancestors following colonization of a cave system; however, very few studies have raised the possibility of "subterranean speciation" in underground habitats (i.e., obligate cave-dwelling organisms [troglobionts] descended from troglobiotic ancestors).

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Article Synopsis
  • Food web dynamics are essential for understanding the ecology of ecosystems, but studying trophic interactions in groundwater ecosystems is challenging due to their hidden nature.
  • Researchers applied a complex Bayesian mixing model to analyze the diets of subterranean beetles and their prey, using various isotopic data and genetic information to refine their findings.
  • Their results showed that the most accurate feeding preferences were determined using the multi-factorial Bayesian model, emphasizing that amphipods were consistently preferred by the beetles, and the integration of genetic data improved dietary estimates significantly.
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Freshwater ecosystems play a key role in shaping the global carbon cycle and maintaining the ecological balance that sustains biodiversity worldwide. Surficial water bodies are often interconnected with groundwater, forming a physical continuum, and their interaction has been reported as a crucial driver for organic matter (OM) inputs in groundwater systems. However, despite the growing concerns related to increasing anthropogenic pressure and effects of global change to groundwater environments, our understanding of the dynamics regulating subterranean carbon flows is still sparse.

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  • - The subterranean islands hypothesis suggests that many aquatic species in the Yilgarn region are evolutionarily isolated in aquifers, leading to limited understanding of terrestrial subterranean invertebrates found in calcretes.
  • - Researchers studied subterranean Collembola species from the Yilgarn calcretes to see if troglobitic species in non-aquatic areas are also limited in distribution, using mtDNA barcoding to analyze 183 individuals from this genus.
  • - Findings revealed at least 25 new Collembola species, highlighting a rich diversity within just 10 calcretes, indicating a complex evolutionary history shaped by environmental changes in Australia’s arid zone.
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  • The Parabathynellidae family, a little-researched group of crustaceans in Australia, has many unsurveyed habitats, particularly in the Pilbara region.
  • Researchers used molecular techniques on genetic data to discover between eight and 24 potential new species from this area.
  • The findings reveal a significant increase in known biodiversity of Parabathynellidae, highlighting the importance of exploring new localities as many species appear to be geographically restricted and represent only a small portion of Australia.
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Subterranean ecosystems host highly adapted aquatic invertebrate biota which play a key role in sustaining groundwater ecological functioning and hydrological dynamics. However, functional biodiversity studies in groundwater environments, the main source of unfrozen freshwater on Earth, are scarce, probably due to the cryptic nature of the systems. To address this, we investigate groundwater trophic ecology via stable isotope analysis, employing δ13C and δ15N in bulk tissues, and amino acids.

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The formation of the Australian arid zone, Australia's largest and youngest major biome, has been recognized as a major driver of rapid evolutionary radiations in terrestrial plants and animals. Here, we investigate the phylogenetic diversity and evolutionary history of subterranean short-tailed whip scorpions (Schizomida: Hubbardiidae), which are a significant faunal component of Western Australian hypogean ecosystems. We sequenced two mitochondrial (12S, COI) and three nuclear DNA markers (18S, 28S, ITS2) from ∼600 specimens, largely from the genera Draculoides and Paradraculoides, including 20 previously named species and an additional 56 newly identified operational taxonomic units (OTUs).

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