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

Escape path complexity and its context dependency in Pacific blue-eyes (Pseudomugil signifer)

The escape trajectories animals take following a predatory attack appear to show high degrees of apparent 'randomness' - a property that has been described as 'protean behaviour'. Here we present a method of quantifying the escape trajectories of individual animals using a path complexity approach. When fish (Pseudomugil signifer) were attacked either on their own or in groups, we find that an individual's path rapidly increases in entropy (our measure of complexity) following the attack. For individuals on their own, this entropy remains elevated (indicating a more random path) for a sustained period (10 seconds) after the attack, whilst it falls more quickly for individuals in groups. The entropy of the path is context dependent. When attacks towards single fish come from greater distances, a fish's path shows less complexity compared to attacks that come from short range. This context dependency effect did not exist, however, when individuals were in groups. Nor did the path complexity of individuals in groups depend on a fish's local density of neighbours. We separate out the components of speed and direction changes to determine which of these components contributes to the overall increase in path complexity following an attack. We found that both speed and direction measures contribute similarly to an individual's path's complexity in absolute terms. Our work highlights the adaptive behavioural tactics that animals use to avoid predators and also provides a novel method for quantifying the escape trajectories of animals.Comment: 9 page

Employing the Precautionary Principle to Evaluate the Use of E-Cigarettes

Electronic cigarettes (e-cigarettes) have emerged onto the public market as an alternative to tobacco cigarettes; however, science is inconclusive as e-cigarettes have not been thoroughly investigated, including their short- and long-term risks and benefits (1, 2). The question arises of whether e-cigarettes will become the future tobacco crisis. This paper connects the precautionary principle to the use of e-cigarettes in an effort to guide decision-makers in the prevention of adverse health outcomes and societal costs

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

Effects of In-Season Velocity- Versus Percentage-Based Training in Academy Rugby League Players

Purpose: To compare the effects of velocity-based training (VBT) versus percentage-based training (PBT) on strength, speed and jump performance in academy rugby league players during a 7-week in-season mesocycle. Methods: Twenty-seven rugby league players competing in the Super League U19s Championship were randomised to VBT (n = 12) or PBT (n = 15). Both groups completed a 7-week resistance training intervention (2x/week) that involved the back squat. The PBT group used a fixed load based on a percentage of one repetition maximum (1RM), whereas the VBT group used a modifiable load based on individualised velocity thresholds. Biomechanical and perceptual data were collected during each training session. Back squat 1RM, countermovement jump (CMJ), reactive strength index (RSI), sprint times, and back squat velocity at 40-90% 1RM were assessed pre- and post-training. Results: The PBT group showed likely to most likely improvements in 1RM strength and RSI, whereas the VBT group showed likely to very likely improvements in 1RM strength, CMJ height, and back squat velocity at 40 and 60% 1RM. Sessional velocity and power were most likely greater during VBT compared with PBT (standardised mean differences [SMDs] = 1.8 to 2.4), whilst time under tension and perceptual training stress were likely lower (SMDs = 0.49 to 0.66). The improvement in back squat velocity at 60% 1RM was likely greater following VBT compared with PBT (SMD = 0.50). Conclusion: VBT can be implemented during the competitive season, instead of traditional PBT, to improve training stimuli, decrease training stress, and promote velocity-specific adaptations

Early respiratory viral infections in infants with cystic fibrosis

This article is made available for unrestricted research re-use and secondary analysis in any form or by any means with acknowledgement of the original source. These permissions are granted for the duration of the World Health Organization (WHO) declaration of COVID-19 as a global pandemic.Background Viral infections contribute to morbidity in cystic fibrosis (CF), but the impact of respiratory viruses on the development of airway disease is poorly understood. Methods Infants with CF identified by newborn screening were enrolled prior to 4 months of age to participate in a prospective observational study at 4 centers. Clinical data were collected at clinic visits and weekly phone calls. Multiplex PCR assays were performed on nasopharyngeal swabs to detect respiratory viruses during routine visits and when symptomatic. Participants underwent bronchoscopy with bronchoalveolar lavage (BAL) and a subset underwent pulmonary function testing. We present findings through 8.5 months of life. Results Seventy infants were enrolled, mean age 3.1 ± 0.8 months. Rhinovirus was the most prevalent virus (66%), followed by parainfluenza (19%), and coronavirus (16%). Participants had a median of 1.5 viral positive swabs (range 0–10). Past viral infection was associated with elevated neutrophil concentrations and bacterial isolates in BAL fluid, including recovery of classic CF bacterial pathogens. When antibiotics were prescribed for respiratory-related indications, viruses were identified in 52% of those instances. Conclusions Early viral infections were associated with greater neutrophilic inflammation and bacterial pathogens. Early viral infections appear to contribute to initiation of lower airway inflammation in infants with CF. Antibiotics were commonly prescribed in the setting of a viral infection. Future investigations examining longitudinal relationships between viral infections, airway microbiome, and antibiotic use will allow us to elucidate the interplay between these factors in young children with CF

Morphological differences between habitats are associated with physiological and behavioural trade-offs in stickleback (Gasterosteus aculeatus)

F.S. and A.J.W.W. were supported by the Australian Research Council, M.M.W. was supported by The University of St Andrews and R.S.J. and J.T. were supported by Coventry UniversityLocal specialization can be advantageous for individuals and may increase the resilience of the species to environmental change. However, there may be trade-offs between morphological responses and physiological performance and behaviour. Our aim was to test whether habitat-specific morphology of stickleback (Gasterosteus aculeatus) interacts with physiological performance and behaviour at different salinities. We rejected the hypothesis that deeper body shape of fish from habitats with high predation pressure led to decreases in locomotor performance. However, there was a trade-off between deeper body shape and muscle quality. Muscle of deeper-bodied fish produced less force than that of shallow-bodied saltmarsh fish. Nonetheless, saltmarsh fish had lower swimming performance, presumably because of lower muscle mass overall coupled with smaller caudal peduncles and larger heads. Saltmarsh fish performed better in saline water (20 ppt) relative to freshwater and relative to fish from freshwater habitats. However, exposure to salinity affected shoaling behaviour of fish from all habitats and shoals moved faster and closer together compared with freshwater. We show that habitat modification can alter phenotypes of native species, but local morphological specialization is associated with trade-offs that may reduce its benefits.Publisher PDFPeer reviewe

Spiny Mice (\u3cem\u3eAcomys\u3c/em\u3e) Exhibit Attenuated Hallmarks of Aging and Rapid Cell Turnover after UV Exposure in the Skin Epidermis

The study of long-lived and regenerative animal models has revealed diverse protective responses to stressors such as aging and tissue injury. Spiny mice (Acomys) are a unique mammalian model of skin wound regeneration, but their response to other types of physiological skin damage has not been investigated. In this study, we examine how spiny mouse skin responds to acute UVB damage or chronological aging compared to non-regenerative C57Bl/6 mice (M. musculus). We find that, compared to M. musculus, the skin epidermis in A. cahirinus experiences a similar UVB-induced increase in basal cell proliferation but exhibits increased epidermal turnover. Notably, A. cahirinus uniquely form a suprabasal layer co-expressing Keratin 14 and Keratin 10 after UVB exposure concomitant with reduced epidermal inflammatory signaling and reduced markers of DNA damage. In the context of aging, old M. musculus animals exhibit typical hallmarks including epidermal thinning, increased inflammatory signaling and senescence. However, these age-related changes are absent in old A. cahirinus skin. Overall, we find that A. cahirinus have evolved novel responses to skin damage that reveals new aspects of its regenerative phenotype

Relationship between secondary health conditions and life satisfaction in persons with spinal cord injury:study across twenty-one countries

Purpose: To determine the relationships between impact of secondary health conditions (SHCs), treatment of SHCs, and life satisfaction (LS) following spinal cord injury (SCI) across 21 countries. Hypotheses were as follows: (1) Persons with SCI and fewer SHCs report higher LS and (2) Persons who receive treatment for SHCs report higher LS than those who do not receive treatment.Methods: Cross-sectional survey, including 10,499 persons with traumatic or non-traumatic SCI aged 18 years or older and living in the community. To assess SHCs, 14 items adapted from the SCI-Secondary Conditions Scale were used (range 1–5). SHCs index was calculated as the mean of all 14 items. LS was assessed using a selection of 5 items from the World Health Organization Quality of Life Assessment. LS index was calculated as the mean of these 5 items. Results: South Korea, Germany, and Poland exhibited the highest (2.40–2.93) and Brazil, China, and Thailand the lowest (1.79–1.90) impact of SHCs. Indexes for LS and SHCs were inversely correlated (– 0.418; p &lt; 0.001). Mixed Model Analysis showed that the fixed effect (key predictors of the study) of SHCs index (p &lt; 0.001) and the positive interaction between SHCs index and treatment (p = 0.002) were significant determinants of LS.Conclusion: Persons with SCI across the world are more likely to perceive better LS if they experience fewer SHCs and receive treatment for SHCs, in comparison to those who do not. Prevention and treatment of SHCs following SCI should be a high priority in order to improve the lived experience and enhance LS.</p