427 research outputs found
Melanism as a potential thermal benefit in eastern fox squirrels (Sciurus niger)
Melanistic fox squirrels (Sciurus niger) have expanded westward and increased in frequency in the Omaha, Nebraska, and Council Bluffs, Iowa, metropolitan areas. The selective advantage of melanism is currently unknown, but thermal advantages have been hypothesized, especially in winter. No difference in metabolic response curves were measured between melanistic (black) and rufus (orange) fox squirrels. When exposed to sunny skies, both melanistic and rufus squirrels had higher surface (skin and fur) temperature as ambient temperatures increased. Melanistic squirrel surface temperatures did not differ when squirrels were exposed to sunny or cloudy skies. However, rufus individuals showed significantly lower increases in surface temperatures when under cloudy skies. During fall months, rufus individuals were about 1.5 times more active throughout the day than melanistic individuals. However, in winter, melanistic fox squirrels were approximately 30% more active in the mornings (before 13:00) compared to rufus squirrels. Pre-winter body condition was higher in melanistic (25.5 ± 1.8 g/cm) compared to rufus (20.30 ± 3.6 g/cm) fox squirrels; however, there were no significant differences between melanistic (22.8 ± 1.4 g/cm) and rufus (23.9 ± 0.8 g/cm) fox squirrel post-winter body condition. The results of this study indicate that melanistic fox squirrels may have a slight winter thermal advantage over rufus fox squirrels by maintaining higher skin temperatures
Erratum to: Melanism as a potential thermal benefit in eastern fox squirrels (Sciurus niger)
Melanistic fox squirrels (Sciurus niger) have expanded westward and increased in frequency in the Omaha, Nebraska, and Council Bluffs, Iowa, metropolitan areas. The selective advantage of melanism is currently unknown, but thermal advantages have been hypothesized, especially in winter. No difference in metabolic response curves were measured between melanistic (black) and rufus (orange) fox squirrels. When exposed to sunny skies, both melanistic and rufus squirrels had higher surface (skin and fur) temperature as ambient temperatures increased. Melanistic squirrel surface temperatures did not differ when squirrels were exposed to sunny or cloudy skies. However, rufus individuals showed significantly lower increases in surface temperatures when under cloudy skies. During fall months, rufus individuals were about 1.5 times more active throughout the day than melanistic individuals. However, in winter, melanistic fox squirrels were approximately 30% more active in the mornings (before 13:00) compared to rufus squirrels. Pre-winter body condition was higher in melanistic (25.5 ± 1.8 g/cm) compared to rufus (20.30 ± 3.6 g/cm) fox squirrels; however, there were no significant differences between melanistic (22.8 ± 1.4 g/cm) and rufus (23.9 ± 0.8 g/cm) fox squirrel post-winter body condition. The results of this study indicate that melanistic fox squirrels may have a slight winter thermal advantage over rufus fox squirrels by maintaining higher skin temperatures
Assessing the use of artificial substrates to monitor Gambierdiscus populations in the Florida Keys
© The Author(s), 2017. This is the author's version of the work. It is posted here under a nonexclusive, irrevocable, paid-up, worldwide license granted to WHOI. It is made available for personal use, not for redistribution. The definitive version was published in Harmful Algae 68 (2017): 52-66, doi:10.1016/j.hal.2017.07.007.Four distinct coastal locations were sampled on a monthly basis near Long Key (Florida Keys,
USA) over a 13-month period to study Gambierdiscus population dynamics on different
substrates, including four macrophyte species (Dictyota spp., Halimeda spp., Laurencia spp., and
Thalassia testudinum) and three artificial substrates (polyvinyl chloride (PVC) tiles, burlap, and
fiberglass window screen). Cell densities of Gambierdiscus were generally lower on Dictyota
versus Halimeda and Laurencia. Cell densities of Gambierdiscus were significantly correlated
among macrophyte hosts in 54% of the comparisons, and between macrophyte hosts and
artificial substrates in 72% of the comparisons. Predictive slopes determined from regression
analyses between cell densities on artificial substrates and macrophyte hosts indicated that, on an
areal basis, fewer cells were present on macrophytes versus artificial substrates (cells cm-2) and
that slope variation (error) among the different macrophytes and sites ranged from 5% to 200%,
averaging 61% overall. As the data required log-transformation prior to analyses, this level of
error translates into two-orders of magnitude in range of estimation of the overall average
abundance of Gambierdiscus cells on macrophytes (135 cells g-1 wet weight); 20 to 2690 cells g-1 ww. The lack of consistent correlation among Gambierdiscus cell densities on macrophytes
versus artificial substrates, coupled with the high level of error associated with the predictive
slope estimations, indicates that extreme caution should be taken when interpreting the data
garnered from artificial substrate deployments, and that such deployments should be thoroughly
vetted prior to routine use for monitoring purposes.Funding for this work was provided by NOAA NOS
(Cooperative Agreements NA11NOS478-0060 and NA11NOS4780028)
Relationships between affiliative social behavior and hair cortisol concentrations in semi-free ranging rhesus monkeys
Sociality is a fundamental aspect of human behavior and health. One benefit of affiliative social relationships is reduced short-term levels of glucocorticoids (GCs), which are indicative of physiological stress. Less is known, however, about chronic GC production in relation to affiliative social behavior. To address this issue, we studied a semi-free ranging troop of rhesus macaques (Macaca mulatta) and collected hair samples to measure hair cortisol concentrations (HCCs), as a measure of chronic GC production, during routine biannual exams. We collected social behavior (both aggressive and affiliative) and hair samples for 32 adult female rhesus macaques over one year (Experiment 1). Our results indicated that adult females who initiated higher levels of social affiliation had significantly lower levels of HCCs. Neither the initiation nor the receipt of aggression were significantly related to HCCs in this study. In a second experiment we studied 28 mother-infant dyads for the first 90 days postpartum to examine mother-infant facial interactions (i.e. mutual gazing). We analyzed HCCs during weaning approximately one year later, which is a major transitional period. We found that infants that engaged in higher levels of mutual gazing in the first 90 days postpartum had significantly lower levels of HCCs during weaning. Finally, we studied 17 infant rhesus macaques (13 males) to examine whether social behavior (such as play) in the first five months of life correlated with infant HCCs over those months (Experiment 3). We found that infant males that engaged in more social play had significantly lower levels of HCCs. By relying on an animal model, our study shows that affiliative social traits are associated with lower long-term GC production. Future research should address the complex interactions between social behavior, chronic GC production, and mental and physical health
Results of a feasibility randomised controlled trial (RCT) for WATCH IT: a programme for obese children and adolescents
Background: In the evaluation of childhood obesity interventions, few researchers undertake a rigorous feasibility stage in which the design and procedures of the evaluation process are examined. Consequently, phase III studies often demonstrate methodological weaknesses. Purpose: Our aim was to conduct a feasibility trial of the evaluation of WATCH IT, a community obesity intervention for children and adolescents. We sought to determine an achievable recruitment rate; acceptability of randomisation, assessment procedures, and dropout rate; optimal outcome measures for the definitive trial; and a robust sample size calculation. Method: Our goal was to recruit 70 participants over 6 months, randomise them to intervention or control group, and retain participation for 12 months. Assessments were taken prior to randomisation and after 6 and 12 months. Procedures mirrored those intended for a full-scale trial, but multiple measures of similar outcomes were included as a means to determine those most appropriate for future research. Acceptability of the research and impact of the research on the programme were ascertained through interviewing participants and staff. Results: We recruited 70 participants and found that randomisation and data collection procedures were acceptable. Self-referral (via media promotion) was more effective than professional referral. Blinding of assessors was sustained to a reasonable degree, and optimal outcome measures for a full-scale trial were identified. Estimated sample size was significantly greater than sample sized reported in published trials. There was some negative impact on the existing programme as a result of the research, a lesson for designers of future trials. Limitations: We successfully recruited socially disadvantaged families, but the majority of families were of White British nationality. The composition of the participants was an added valuable lesson, suggesting that recruitment strategies to obtain a more heterogeneous ethnic sample warrant consideration in future research. Conclusions: This study provided us with confidence that we can run a phase III multi-centre trial to test the effectiveness of WATCH IT. Importantly, it was invaluable in informing the design not only of that trial but also of future evaluations of childhood obesity treatment interventions
A typology of drought decision making: Synthesizing across cases to understand drought preparedness and response actions
Drought is an inescapable reality in many regions, including much of the western United States. With climate change, droughts are predicted to intensify and occur more frequently, making the imperative for drought management even greater. Many diverse actors â including private landowners, business owners, scientists, non-governmental organizations (NGOs), and managers and policymakers within tribal, local, state, and federal government agencies â play multiple, often overlapping roles in preparing for and responding to drought. Managing water is, of course, one of the most important roles that humans play in both mitigating and responding to droughts; but, focusing only on âwater managersâ or âwater managementâ fails to capture key elements related to the broader category of drought management. The respective roles played by those managing drought (as distinct from water managers), the interactions among them, and the consequences in particular contexts, are not well understood. Our team synthesized insights from 10 in-depth case studies to understand key facets of decision making about drought preparedness and response. We present a typology with four elements that collectively describe how decisions about drought preparedness and response are made (context and objective for a decision; actors responsible; choice being made or action taken; and how decisions interact with and influence other decisions). The typology provides a framework for system-level understanding of how and by whom complex decisions about drought management are made. Greater system-level understanding helps decision makers, program and research funders, and scientists to identify constraints to and opportunities for action, to learn from the past, and to integrate ecological impacts, thereby facilitating social learning among diverse participants in drought preparedness and response
Human-AI Teaming During an Ongoing Disaster: How Scripts Around Training and Feedback Reveal this is a Form of Human-Machine Communication
Humans play an integral role in identifying important information from social media during disasters. While human annotation of social media data to train machine learning models is often viewed as human-computer interaction, this study interrogates the ontological boundary between such interaction and human-machine communication. We conducted multiple interviews with participants who both labeled data to train machine learning models and corrected machine-inferred data labels. Findings reveal three themes: scripts invoked to manage decision-making, contextual scripts, and scripts around perceptions of machines. Humans use scripts around training the machineâa form of behavioral anthropomorphismâto develop social relationships with them. Correcting machine-inferred data labels changes these scripts and evokes self-doubt around who is right, which substantiates the argument that this is a form of human-machine communication
Lipidomic Evaluation of Feline Neurologic Disease after AAV Gene Therapy
GM1 gangliosidosis is a fatal lysosomal disorder, for which there is no effective treatment. Adeno-associated virus (AAV) gene therapy in GM1 cats has resulted in a greater than 6-fold increase in lifespan, with many cats remaining alive at \u3e 5.7 years of age, with minimal clinical signs. Glycolipids are the principal storage product in GM1 gangliosidosis whose pathogenic mechanism is not completely understood. Targeted lipidomics analysis was performed to better define disease mechanisms and identify markers of disease progression for upcoming clinical trials in humans. 36 sphingolipids and subspecies associated with ganglioside biosynthesis were tested in the cerebrospinal fluid of untreated GM1 cats at a humane endpoint ( approximately 8 months), AAV-treated GM1 cats ( approximately 5 years old), and normal adult controls. In untreated GM1 cats, significant alterations were noted in 16 sphingolipid species, including gangliosides (GM1 and GM3), lactosylceramides, ceramides, sphingomyelins, monohexosylceramides, and sulfatides. Variable degrees of correction in many lipid metabolites reflected the efficacy of AAV gene therapy. Sphingolipid levels were highly predictive of neurologic disease progression, with 11 metabolites having a coefficient of determination (R(2)) \u3e 0.75. Also, a specific detergent additive significantly increased the recovery of certain lipid species in cerebrospinal fluid samples. This report demonstrates the methodology and utility of targeted lipidomics to examine the pathophysiology of lipid storage disorders
Neonatal face-to-face interactions promote later social behaviour in infant rhesus monkeys
In primates, including humans, mothers engage in face-to-face interactions with their infants, with frequencies varying both within and across species. However, the impact of this variation in face-to-face interactions on infant social development is unclear. Here we report that infant monkeys (Macaca mulatta) who engaged in more neonatal face-to-face interactions with mothers have increased social interactions at 2 and 5 months. In a controlled experiment, we show that this effect is not due to physical contact alone: monkeys randomly assigned to receive additional neonatal face-to-face interactions (mutual gaze and intermittent lip-smacking) with human caregivers display increased social interest at 2 months, compared with monkeys who received only additional handling. These studies suggest that face-to-face interactions from birth promote young primate social interest and competenc
Glucocorticoids accelerate maturation of the heme pathway in fetal liver through effects on transcription and DNA methylation
<p>Glucocorticoids are widely used in threatened preterm labor to promote maturation in many organ systems in preterm babies and have significant beneficial effects on morbidity and mortality. We performed transcriptional profiling in fetal liver in a rat model of prenatal glucocorticoid exposure and identified marked gene expression changes in heme biosynthesis, utilization, and degradation pathways in late gestation. These changes in gene expression associated with alterations in DNA methylation and with a reduction in hepatic heme concentration. There were no persistent differences in gene expression, DNA methylation, or heme concentrations at 4 weeks of age, suggesting that these are transient effects. Our findings are consistent with glucocorticoid-induced accelerated maturation of the haematopoietic system and support the hypothesis that glucocorticoids can drive changes in gene expression in association with alterations in DNA methylation.</p
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