Habitat loss and change are often implicated as the primary causes of species extinction. Although any population can be instantly imperiled by catastrophe, most habitat loss occurs gradually, thus enabling affected individuals an adaptive advantage to occupy the best of their dwindling opportunities. I demonstrate how to infer the advantage between two habitats for any density and frequency-dependent strategy of habitat selection.
View Article and Find Full Text PDFPurpose: We hypothesized that the time-dependent diffusivity at short diffusion times, as measured by oscillating gradient spin echo (OGSE) diffusion MRI, can characterize tissue microstructures in glioma patients.
Theory And Methods: Five adult patients with known diffuse glioma, including two pre-surgical and three with new enhancing lesions after treatment for high-grade glioma, were scanned in an ultra-high-performance gradient 3.0T MRI system.
The coexistence of competing species requires density feedbacks that have a larger effect on their own species' population growth than they do on others in the assembly. The feedbacks are often associated with behavioral tradeoffs that enable species to differentially exploit underlying axes of heterogeneity. Conjoining theories of species coexistence with foraging behavior and density-dependent habitat selection reveals that such tradeoffs impinge on invasion probabilities and equilibrium dynamics emerging from species' differences in habitat use.
View Article and Find Full Text PDFPurpose: Asymmetric gradient coils introduce zeroth- and first-order concomitant field terms, in addition to higher-order terms common to both asymmetric and symmetric gradients. Salient to compensation strategies is the accurate calibration of the concomitant field spatial offset parameters for asymmetric coils. A method that allows for one-time calibration of the offset parameters is described.
View Article and Find Full Text PDFJ Am Acad Psychiatry Law
September 2022
Most competence restoration occurs in secure inpatient settings. As states struggle with strained resources and seek to best utilize restoration services, factors such as charge severity and violence risk remain key considerations in determining the appropriate setting for an individual's competence restoration. This study offers a quantitative analysis of aggressive behavior during inpatient restoration efforts and whether criminal charge severity correlates with inpatient aggression.
View Article and Find Full Text PDFI merge publicly available data on CO2 emissions, with patterns of human movement, to analyze the anticipated effects of human migration on the abilities of nations to attain 2030 UNFCCC CO2 emission targets. I do so at both global (175 countries) and national (Canada and the USA) scales. The analyses reveal that mean per capita CO2 emissions are nearly three times higher in countries with net immigration than in countries with net emigration.
View Article and Find Full Text PDFMultiple-choice (MC) anatomy "spot-tests" (identification-based assessments on tagged cadaveric specimens) offer a practical alternative to traditional free-response (FR) spot-tests. Conversion of the two spot-tests in an upper limb musculoskeletal anatomy unit of study from FR to a novel MC format, where one of five tagged structures on a specimen was the answer to each question, provided a unique opportunity to assess the comparative validity and reliability of FR- and MC-formatted spot-tests and the impact on student performance following the change of test format to MC. Three successive year cohorts of health science students (n = 1,442) were each assessed by spot-tests formatted as FR (first cohort) or MC (following two cohorts).
View Article and Find Full Text PDFHabitat selection is expected to balance benefits and costs that maximizes fitness. Using a rare data set on collared lemming (Dicrostonyx groenlandicus) winter nest location spanning more than two decades, we show that lemmings actively select for Salix snow beds, likely due to its favorable micro-climate, and that lemming habitat selection was density-dependent. Lemmings nevertheless exhibited some flexibility in their habitat selection, which appeared to be influenced by the year-to-year variation in snow conditions.
View Article and Find Full Text PDFPurpose: Demonstrating multifield and inverse contrast switching of magnetocaloric high contrast ratio MRI labels that either have increasing or decreasing moment versus temperature slopes depending on the material at physiological temperatures and different MRI magnetic field strengths.
Methods: Two iron-rhodium samples of different purity (99% and 99.9%) and a lanthanum-iron-silicon sample were obtained from commercial vendors.
Periodontal disease is an age-associated disorder clinically defined by periodontal bone loss, inflammation of the specialized tissues that surround and support the tooth, and microbiome dysbiosis. Currently, there is no therapy for reversing periodontal disease, and treatment is generally restricted to preventive measures or tooth extraction. The FDA-approved drug rapamycin slows aging and extends lifespan in multiple organisms, including mice.
View Article and Find Full Text PDFAn optimal habitat-selecting organism should use a dispersal strategy that enables occupation of the habitat yielding greatest fitness. The strategy is complicated when habitat quality varies through time. Theory predicts that the long-term distribution of individuals will match mean habitat quality while undermatching current habitat quality.
View Article and Find Full Text PDFUnderstanding how events at the molecular and cellular scales contribute to tissue form and function is key to uncovering the mechanisms driving animal development, physiology and disease. Elucidating these mechanisms has been enhanced through the study of model organisms and the use of sophisticated genetic, biochemical and imaging tools. Here, we present an accessible method for non-invasive imaging of at high resolution using micro-computed tomography (µ-CT).
View Article and Find Full Text PDFLemmings are a key component of tundra food webs and changes in their dynamics can affect the whole ecosystem. We present a comprehensive overview of lemming monitoring and research activities, and assess recent trends in lemming abundance across the circumpolar Arctic. Since 2000, lemmings have been monitored at 49 sites of which 38 are still active.
View Article and Find Full Text PDFNeurodevelopmental disorders (NDD) are genetically and phenotypically heterogeneous conditions due to defects in genes involved in development and function of the nervous system. Individuals with NDD, in addition to their primary neurodevelopmental phenotype, may also have accompanying syndromic features that can be very helpful diagnostically especially those with recognizable facial appearance. In this study, we describe ten similarly affected individuals from six unrelated families of different ethnic origins having bi-allelic truncating variants in TMEM94, which encodes for an uncharacterized transmembrane nuclear protein that is highly conserved across mammals.
View Article and Find Full Text PDFPurpose: To develop switchable and tunable labels with high contrast ratio for MRI using magnetocaloric materials that have sharp first-order magnetic phase transitions at physiological temperatures and typical MRI magnetic field strengths.
Methods: A prototypical magnetocaloric material iron-rhodium (FeRh) was prepared by melt mixing, high-temperature annealing, and ice-water quenching. Temperature- and magnetic field-dependent magnetization measurements of wire-cut FeRh samples were performed on a vibrating sample magnetometer.
The hereditary spastic paraplegias (HSP) are a clinically and genetically heterogeneous group of disorders characterized by progressive lower limb spasticity. Mutations in subunits of the heterotetrameric (ε-β4-μ4-σ4) adaptor protein 4 (AP-4) complex cause an autosomal recessive form of complicated HSP referred to as "AP-4 deficiency syndrome". In addition to lower limb spasticity, this syndrome features intellectual disability, microcephaly, seizures, thin corpus callosum and upper limb spasticity.
View Article and Find Full Text PDFBackground: With the recent implementation of the Medicare Quality Payment Program, providers face increasing accountability for delivering high-quality care. Such pay-for-performance programs aim to leverage systematic data captured by electronic health record (EHR) systems to measure performance; however, the fidelity of EHR query for assessing performance has not been validated compared with manual chart review. We sought to determine whether our institution's methodology of EHR query could accurately identify cases in which providers failed to prescribe statins for eligible patients with coronary artery disease.
View Article and Find Full Text PDFBackground: Hippocampal volume loss is a hallmark of clinical depression. Chronic stress produces volume loss in the hippocampus in humans and atrophy of CA3 pyramidal cells and suppression of adult neurogenesis in rodents.
Methods: To investigate the relationship between decreased adult neurogenesis and stress-induced changes in hippocampal structure and volume, we compared the effects of chronic unpredictable restraint stress and inhibition of neurogenesis in a rat pharmacogenetic model.
Federal funding for basic scientific research is the cornerstone of societal progress, economy, health and well-being. There is a direct relationship between financial investment in science and a nation's scientific discoveries, making it a priority for governments to distribute public funding appropriately in support of the best science. However, research grant proposal success rate and funding level can be skewed toward certain groups of applicants, and such skew may be driven by systemic bias arising during grant proposal evaluation and scoring.
View Article and Find Full Text PDFThe neuroinflammatory autoimmune disease Aicardi-Goutières syndrome (AGS) develops from mutations in genes encoding several nucleotide-processing proteins, including RNase H2. Defective RNase H2 may induce accumulation of self-nucleic acid species that trigger chronic type I interferon and inflammatory responses, leading to AGS pathology. We created a knock-in mouse model with an RNase H2 AGS mutation in a highly conserved residue of the catalytic subunit, Rnaseh2a(G37S/G37S) (G37S), to understand disease pathology.
View Article and Find Full Text PDFThe role of human endogenous retroviruses (HERVs) in disease pathogenesis is unclear. We show that HERV-K is activated in a subpopulation of patients with sporadic amyotrophic lateral sclerosis (ALS) and that its envelope (env) protein may contribute to neurodegeneration. The virus was expressed in cortical and spinal neurons of ALS patients, but not in neurons from control healthy individuals.
View Article and Find Full Text PDFPurpose: X-ray irradiation of tumors causes diverse effects on the tumor microenvironment, including metabolism. Recent developments of hyperpolarized (13)C-MRI enabled detecting metabolic changes in tumors using a tracer [1-(13)C]pyruvate, which participates in important bioenergetic processes that are altered in cancers. Here, we investigated the effects of X-ray irradiation on pyruvate metabolism in squamous cell carcinoma (SCCVII) and colon cancer (HT-29) using hyperpolarized (13)C-MRI.
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