Publications by authors named "Cory Williams"

The acute-phase response (APR) is an adaptive emergency life-history stage, wherein vertebrates exhibit fever and anorexia to survive an infection. However, induced immune responses are energetically costly, and sick animals may reduce physical activity to compensate. Tests of this predicted energetic trade-off in free-ranging animals are rare due to difficulties in measuring individual physiology and behaviour under immune challenge in natural settings.

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Surgery is a significant part of healthcare, but its demand is increasing, leading to challenges in managing patient care. Inefficient perioperative practices and traditional linear models contribute to adverse outcomes and patient anxiety. E-health interventions show promise in improving surgical care, but more research is needed.

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Seasonal affective disorder (SAD) is a recurrent depression triggered by exposure to short photoperiods, with a subset of patients reporting hypersomnia, increased appetite, and carbohydrate craving. Dysfunction of the microbiota - gut - brain axis is frequently associated with depressive disorders, but its role in SAD is unknown. Nile grass rats () are potentially useful for exploring the pathophysiology of SAD, as they are diurnal and have been found to exhibit anhedonia and affective-like behavior in response to short photoperiods.

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Background: Patient Reported Experience Measures (PREMs) provide health organisations insight into how 'person-centric' care is. Qualitative data in PREMs surveys provide essential context about experience but are challenging to analyse at an organisational level.

Objective: To co-design a person-centred coding framework to assist in the analysis of qualitative PREMs data.

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Climate warming is rapid in the Arctic, yet impacts to biological systems are unclear because few long-term studies linking biophysiological processes with environmental conditions exist for this data-poor region. In our study spanning 25 years in the Alaskan Arctic, we demonstrate that climate change is affecting the timing of freeze-thaw cycles in the active layer of permafrost soils and altering the physiology of arctic ground squirrels (). Soil freeze has been delayed and, in response, arctic ground squirrels have delayed when they up-regulate heat production during torpor to prevent freezing.

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Stable isotope mixing models (SIMMs) are widely used for characterizing wild animal diets. Such models rely upon using accurate trophic discrimination factors (TDFs) to account for the digestion, incorporation, and assimilation of food. Existing methods to calculate TDFs rely on controlled feeding trials that are time-consuming, often impractical for the study taxon, and may not reflect natural variability of TDFs present in wild populations.

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Seasonal variation in the availability of essential resources is one of the most important drivers of natural selection on the phasing and duration of annually recurring life-cycle events. Shifts in seasonal timing are among the most commonly reported responses to climate change and the capacity of organisms to adjust their timing, either through phenotypic plasticity or evolution, is a critical component of resilience. Despite growing interest in documenting and forecasting the impacts of climate change on phenology, our ability to predict how individuals, populations, and species might alter their seasonal timing in response to their changing environments is constrained by limited knowledge regarding the cues animals use to adjust timing, the endogenous genetic and molecular mechanisms that transduce cues into neural and endocrine signals, and the inherent capacity of animals to alter their timing and phasing within annual cycles.

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Article Synopsis
  • Many animals, including the arctic ground squirrel, adjust their seasonal behaviors (like reproduction and hibernation) based on temperature changes, but the exact mechanisms are still not fully understood.
  • Research indicates that a signaling pathway involving the hormone thyrotropin (TSH) and thyroid hormones (TH) plays a key role in regulating these seasonal changes in the brain.
  • In a study, male arctic ground squirrels exposed to warmer temperatures showed increased TSH expression and testis mass, while females showed less impact, suggesting potential mismatches in reproductive timing due to rapid climate changes.
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The regulation of seasonality has been an area of interest for decades, yet global climate change has created extra urgency in the quest to understand how sensory circuits and neuroendocrine control systems interact to generate flexibility in biological timekeeping. The capacity of temperature to alter endogenous or photoperiod-regulated neuroendocrine mechanisms driving seasonality, either as a direct cue or through temperature-dependent effects on energy and metabolism, is at the heart of this phenological flexibility. However, until relatively recently, little research had been done on the integration of temperature information in canonical seasonal neuroendocrine pathways, particularly in vertebrates.

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  • * In arctic ground squirrels, researchers found that hibernation triggers a series of hormonal changes that alter brain cells and activate reproductive systems, which may prepare them for the upcoming summer.
  • * Forcing these squirrels to wake up early led to specific hormonal changes in their brains, but did not activate their reproductive systems further, suggesting that the hibernation cycle is crucial for preparing for the brief summer period.
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Shifts in the timing of cyclic seasonal life-history events are among the most commonly reported responses to climate change, with differences in response rates among interacting species leading to phenological mismatches. Within a species, however, males and females can also exhibit differential sensitivity to environmental cues and may, therefore, differ in their responsiveness to climate change, potentially leading to phenological mismatches between the sexes. This occurs because males differ from females in when and how energy is allocated to reproduction, resulting in marked sex-differences in life-history timing across the annual cycle.

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Intra- and inter-specific resource partitioning within predator communities is a fundamental component of trophic ecology, and one proposed mechanism for how populations partition resources is through individual niche variation. The Niche Variation Hypothesis (NVH) predicts that inter-individual trait variation leads to functional trade-offs in foraging efficiency, resulting in populations composed of individual dietary specialists. The degree to which niche specialization persists within a population is plastic and responsive to fluctuating resource availability.

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The development of animal models is a critical step for exploring the underlying pathophysiological mechanisms of major affective disorders and for evaluating potential therapeutic approaches. Although most neuropsychiatric research is performed on nocturnal rodents, differences in how diurnal and nocturnal animals respond to changing photoperiods, combined with a possible link between circadian rhythm disruption and affective disorders, has led to a call for the development of diurnal animal models. The need for diurnal models is most clear for seasonal affective disorder (SAD), a widespread recurrent depressive disorder that is linked to exposure to short photoperiods.

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Hibernation is a unique evolutionary adaptation to conserve energy. During the pre-hibernation (i.e.

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Bayesian stable isotope mixing models (BSIMMs) for δ C and δ N can be a useful tool to reconstruct diets, characterize trophic relationships, and assess spatiotemporal variation in food webs. However, use of this approach typically requires a priori knowledge on the level of enrichment occurring between the diet and tissue of the consumer being sampled (i.e.

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The dynamic relationship between glucocorticoids and behavior are not well understood in wild mammals. We investigated how weather, body condition, and reproduction interact to affect cortisol levels and activity patterns in a free-living population of arctic ground squirrels (Urocitellus parryii). As a proxy for foraging and escape behaviors, collar-mounted accelerometers and light loggers were used to measure above-ground activity levels and the amount of time squirrels spent below the surface, respectively.

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Objective: To investigate the relationship between loneliness and non-prescribed opioid use in patients diagnosed with opioid use disorder (OUD).

Methods: This was a cohort study conducted at a federally qualified health center (FQHC) in New Haven, CT. Patients who were treated for OUD by health center providers and prescribed buprenorphine were eligible.

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Article Synopsis
  • Hibernation helps mammals survive when food is scarce, but it can lead to oxidative damage due to reactive oxygen species (ROS) during rewarming.
  • The study focused on arctic ground squirrels and hypothesized that telomere shortening, an indicator of oxidative damage, would vary by tissue type, particularly in brown adipose tissue (BAT) which is crucial for thermogenesis.
  • Results showed that telomere length dynamics differed in various tissues, with juvenile females experiencing more shortening in BAT and skeletal muscle over time, while in males, longer telomere lengths were observed in BAT at late hibernation, potentially linked to their shorter hibernation durations.
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  • Fisher's principle suggests that the sex ratio in sexually reproducing species tends to stabilize at 1:1 due to the advantages of rare sex individuals in reproduction.
  • In a study of North American red squirrels over 26 years, researchers found that while the overall sex ratio remained equal, specific years with an imbalanced adult sex ratio did not lead to a corresponding bias in offspring sex ratios.
  • The study concluded that environmental fluctuations and the independence of adult and offspring sex ratios may undermine the benefits typically expected from producing offspring of the rarer sex.
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Phenological shifts are the most widely reported ecological responses to climate change, but the requirements to distinguish their causes (i.e. phenotypic plasticity vs.

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Hibernation provides a means of escaping the metabolic challenges associated with seasonality, yet the ability of mammals to prolong or reenter seasonal dormancy in response to extreme weather events is unclear. Here, we show that Arctic ground squirrels in northern Alaska exhibited sex-dependent plasticity in the physiology and phenology of hibernation in response to a series of late spring snowstorms in 2013 that resulted in the latest snowmelt on record. Females and nonreproductive males responded to the >1-month delay in snowmelt by extending heterothermy or reentering hibernation after several days of euthermy, leading to a >2-week delay in reproduction compared to surrounding years.

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Tactics of resource use for reproduction are an important feature of life-history strategies. A distinction is made between 'capital' breeders, which finance reproduction using stored energy, and 'income' breeders, which pay for reproduction using concurrent energy intake. In reality, vertebrates use a continuum of capital-to-income tactics, and, for many species, the allocation of capital towards reproduction is a plastic trait.

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Circadian systems are principally entrained to 24 h light-dark cycles, but this cue is seasonally absent in polar environments. Although some resident polar vertebrates have weak circadian clocks and are seasonally arrhythmic, the arctic ground squirrel (AGS) maintains daily rhythms of physiology and behavior throughout the summer, which includes 6 weeks of constant daylight. Here, we show that persistent daily rhythms in AGS are maintained through a circadian system that readily entrains to the polar day yet remains insensitive to entrainment by rapid light-dark transitions, which AGS generate naturally as a consequence of their semi-fossorial behavior.

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Most organisms have a circadian system, entrained to daily light-dark cycles, that regulates 24-h rhythms of physiology and behavior. It is unclear, however, how circadian systems function in animals that exhibit seasonal metabolic suppression, particularly when this coincides with the long-term absence of a day-night cycle. The arctic ground squirrel, Urocytellus parryii, is a medium-sized, semi-fossorial rodent that appears above-ground daily during its short active season in spring and summer before re-entering a constantly dark burrow for 6 to 9 months of hibernation.

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