Challenges of dehydration result in a behavioral shift in invasive toads

The adaptive nature of invasive species facilitates their survival in conditions that differ markedly from their native range. Behavioral changes in invasive populations are poorly explored but offer a wide potential when combined with physiological traits. For amphibians invading xeric habitats, finding water is important to function optimally and avoid dehydration. The water-finding hypothesis postulates that survival can be enhanced through the increased behavioral ability to find water. We tested the water-finding hypothesis in guttural toads (Sclerophrys gutturalis) from their native range and an invasive population. Additionally, we tested if artificially elevated corticosterone levels, which increase during dehydration, affect behavioral traits linked to water balance. In a labyrinth experiment, we observed the toads’ ability to find water in different hydration states (100%, 90%, and 80%). We found that individuals from the invasive population took longer to engage in water-searching behavior and spent more time close to the water source after finding it. Toads from the invasive population were also more active, and at 90% hydration, their attempts to find water increased. Moreover, artificially increasing corticosterone in fully hydrated invasive toads increased water-finding success. Our experiments demonstrated that invasive toads show water-conservation behaviors that can optimize water balance and might facilitate survival in an invaded xeric environment. Additionally, we suggest a link between elevated corticosterone levels and water-finding success. Our results lend support to the importance of behavior in successful invasions and the modulation of water-finding behavior by corticosterone

Importance of diagnostic setting in determining mortality in patients with new-onset heart failure: temporal trends in Denmark 1997–2017

Aim: To investigate temporal trends in inpatient vs. outpatient diagnosis of new-onset heart failure (HF) and the subsequent risk of death and hospitalization. Methods and results: Using nationwide registers, 192 581 patients with a first diagnosis of HF (1997–2017) were included. We computed incidences of HF, age-standardized mortality rates, and absolute risks (ARs) of death and hospitalization (accounting for competing risk of death) to understand the importance of the diagnosis setting in relation to subsequent mortality and hospitalization. The overall incidence of HF was approximately the same (170/100 000 persons) every year during 1997–2017. However, in 1997, 77% of all first diagnoses of HF were made during a hospitalization, whereas the proportion was 39% in 2017. As inpatient diagnoses decreased, outpatient diagnoses increased from 23% to 61%. Outpatients had lower mortality and hospitalization rates than inpatients throughout the study period, although the 1-year age-standardized mortality rate decreased for each inpatient (24 to 14/100-person) and outpatient (11 to 7/100-person). One-year and five-year AR of death decreased by 11.1% and 17.0%, respectively, for all HF patients, while the risk of hospitalization for HF did not decrease significantly (1.13% and 0.96%, respectively). Conclusion: Between 1997 and 2017, HF changed from being primarily diagnosed during hospitalization to being mostly diagnosed in the outpatient setting. Outpatients had much lower mortality rates than inpatients throughout the study period. Despite a significant decrease in mortality risk for all HF patients, neither inpatients nor outpatients experienced a reduction in the risk of an HF hospitalization

Challenges of a novel range: water balance, stress, and immunity in an invasive toad

Species introduced by human activities can alter the normal functioning of ecosystems promoting negative impacts on native biodiversity, as they can rapidly expand their population size, demonstrating phenotypic plasticity and possible adaptive capacity to novel environments. Twenty years ago, the guttural toad, Sclerophrys gutturalis, was introduced to a peri-urban area of Cape Town, with cooler and drier climatic characteristics than its native source population, Durban, South Africa. Our goal was to understand the phenotypic changes, in terms of physiology and immunity, of populations in native and novel environments. We evaluated body index (BI), field hydration level, plasma corticosterone levels (CORT), proportion of neutrophils: lymphocytes (N: L), plasma bacterial killing ability (BKA), and hematocrit (HTC) in the field, and after standardized stressors (dehydration and movement restriction) in males from the native and invasive populations. Toads from the invasive population presented lower BI and tended to show a lower field hydration state, which is consistent with living in the drier environmental conditions of Cape Town. Additionally, invasive toads also showed higher BKA and N:L ratio under field conditions. After exposure to stressors, invasive animals presented higher BKA than the natives. Individuals from both populations showed increased CORT after dehydration, an intense stressor for these animals. The highest BKA and N:L ratio in the field and after submission to stressors in the laboratory shows that the invasive population has a phenotype that might increase their fitness, leading to adaptive responses in the novel environment and, thus, favoring successful dispersion and population increase

Spatial resolution in inverse problems:the EZIE satellite mission

Abstract Inverse modeling has become one of the primary methods for studying ionospheric electrodynamics, especially when using magnetic field measurements from below the ionosphere. We present a method for quantifying the spatial resolution in an inverse model for non-uniformly sampled spatial data. This method provides a tool for assessing if a model can resolve the physical phenomena of interest. We quantify the spatial resolution for the Spherical Elementary Current System basis functions to model the ionospheric dynamics. Our results apply to models with spatially confined model parameters, unlike spherical harmonics where the model parameters describe the amplitude of global surface functions. The method is demonstrated for the upcoming Electrojet Zeeman Imaging Explorer cubesat mission which will provide spatially distributed remote sensing measurements of the magnetic field in the mesosphere. We show that, including measurements from a single ground magnetometer can significantly improve the spatial resolution. However, the impact of including a ground magnetometer depends on the relative position of the station with respect to the mesospheric measurements. In addition, a method for reducing two regularization parameters to one is presented. Reducing the amount of regularization parameters simplifies the optimization problem and facilitates a fair comparison between the models with and without a ground magnetometer

COVID-19 As A Chronic Stressor And The Importance Of Individual Identity: A Data-Driven Look At Academic Productivity During The Pandemic

The COVID-19 pandemic impacted personal and professional life. For academics, research, teaching, and service tasks were upended and we all had to navigate the altered landscape. However, some individuals faced a disproportionate burden, particularly academics with minoritized identities or those who were early career, were caregivers, or had intersecting identities. As comparative endocrinologists, we determine how aspects of individual and species-level variation influence response to, recovery from, and resilience in the face of stressors. Here, we flip that framework and apply an integrative biological lens to the impact of the COVID-19 chronic stressor on our endocrine community. We address how the pandemic altered impact factors of academia (e.g., scholarly products) and relatedly, how factors of impact (e.g., sex, gender, race, career stage, caregiver status, etc.) altered the way in which individuals could respond. We predict the pandemic will have long-term impacts on the population dynamics, composition, and landscape of our academic ecosystem. Impact factors of research, namely journal submissions, were altered by COVID-19, and women authors saw a big dip. We discuss this broadly and then report General and Comparative Endocrinology (GCE) manuscript submission and acceptance status by gender and geographic region from 2019 to 2023. We also summarize how the pandemic impacted individuals with different axes of identity, how academic institutions have responded, compile proposed solutions, and conclude with a discussion on what we can all do to (re)build the academy in an equitable way. At GCE, the first author positions had gender parity, but men outnumbered women at the corresponding author position. Region of manuscript origin mattered for submission and acceptance rates, and women authors from Asia and the Middle East were the most heavily impacted by the pandemic. The number of manuscripts submitted dropped after year 1 of the pandemic and has not yet recovered. Thus, COVID-19 was a chronic stressor for the GCE community

Readmission and death in patients admitted with new-onset versus worsening of chronic heart failure: insights from a nationwide cohort

Aim: To examine the rates of all‐cause mortality and heart failure (HF) readmission in patients hospitalized with decompensated HF according to HF duration – new‐onset HF and worsening of chronic HF. Methods and results: In this nationwide observational cohort study, 17 176 patients were included at first hospital admission for HF in the period 2013–2015 using data from Danish nationwide registries. In total, 8860 (51.6%) patients were admitted with new‐onset HF and 8316 (48.4%) with worsening of chronic HF. Patients with worsening of chronic HF were characterized by a greater comorbidity burden compared with patients with new‐onset HF. The rates of outcomes were examined by multivariable Cox regression models, adjusted for age, sex, and comorbidity. Worsening of chronic HF was associated with a higher rate of the composite endpoint of all‐cause mortality or HF readmission [hazard ratio (HR) 1.37, 95% confidence interval (CI) 1.31–1.43], all‐cause mortality (HR 1.22, 95% CI 1.16–1.28), and HF readmission (HR 1.81, 95% CI 1.69–1.93) compared with new‐onset HF. There was an interaction between atrial fibrillation (AF), HF duration, and outcome: in worsening of chronic HF, the rate of the composite endpoint was higher in patients with AF compared with those without (HR 1.12, 95% CI 1.07–1.19), whereas in new‐onset HF, the rate of the composite endpoint was lower in patients with AF compared with those without (HR 0.91, 95% CI 0.85–0.96) (P‐value for interaction <0.001). Conclusions: Among patients hospitalized with decompensated HF, worsening of chronic HF was associated with poorer outcomes compared with new‐onset HF