Body temperature and activity patterns of free-living laughing kookaburras: the largest kingfisher is heterothermic.

We show that free-ranging Laughing Kookaburras (Dacelo novaeguineae), the largest kingfishers, are heterothermic. Their minimum recorded body temperature (Tb) was 28.6°C, and the maximum daily Tb range was 9.1°C, which makes kookaburras only the second coraciiform species and the only member of the Alcedinidae known to be heterothermic. The amplitude of nocturnal body temperature variation for wild, free-living kookaburras during winter was substantially greater than the mean of 2.6°C measured previously for captive kookaburras. Calculated metabolic savings from nocturnal heterothermia were up to 5.6 ± 0.9 kJ per night. There was little effect of ambient temperature on any of the calculated Tb-dependent variables for the kookaburras, although ambient temperature did influence the time that activity commenced for these diurnal birds. Kookaburras used endogenous metabolic heat production to rewarm from low Tb, rather than relying on passive rewarming. Rewarming rates (0.05 ± 0.01°C min−1) were consistent with those of other avian species. Captivity can have major effects on thermoregulation for birds, and therefore the importance of field studies of wild, free-living individuals is paramount for understanding the biology of avian temperature regulation

Prompt neutrino fluxes in the atmosphere with PROSA parton distribution functions

Effects on atmospheric prompt neutrino fluxes of present uncertainties affecting the nucleon composition are studied by using the PROSA fit to parton distribution functions (PDFs). The PROSA fit extends the precision of the PDFs to low x, which is the kinematic region of relevance for high-energy neutrino production, by taking into account LHCb data on charm and bottom hadroproduction. In the range of neutrino energies explored by present Very Large Volume Neutrino Telescopes, it is found that PDF uncertainties are far smaller with respect to those due to renormalization and factorization scale variation and to assumptions on the cosmic ray composition, which at present dominate and limit our knowledge of prompt neutrino fluxes. A discussion is presented on how these uncertainties affect the expected number of atmospheric prompt neutrino events in the analysis of high-energy events characterized by interaction vertices fully contained within the instrumented volume of the detector, performed by the IceCube collaboration.Comment: 36 pages, 17 figures, 1 tabl

Snoozing through the storm: torpor use during a natural disaster

Although storms provide an extreme environmental challenge to organisms and are predicted to increase in frequency and intensity due to climate change, there are no quantitative observations on the behaviour and physiology of animals during natural disasters. We provide the first data on activity and thermal biology of a free-ranging, arboreal mammal during a storm with heavy rain and category 1 cyclone wind speeds. We studied a population of sugar gliders (Petaurus breviceps), a species vulnerable to bad weather due to their small body size and mode of locomotion, in a subtropical habitat during spring when storms are common. Although torpor is generally rare in this species, sugar gliders remained inactive or reduced foraging times during the storm and further minimized energy demands by entering deep torpor. All animals survived the storm and reverted to normal foraging activity during the following night(s). It thus appears that heterothermic mammals have a crucial adaptive advantage over homeothermic species as they can outlast challenging weather events, such as storms and floods, by reducing metabolism and thus energetic needs

A new cue for torpor induction: charcoal, ash and smoke

Recent work has shown that the use of torpor for energy conservation increases after forest fires in heterothermic mammals, probably in response to the reduction of food. However, the specific environmental cues for this increased torpor expression remain unknown. It is possible that smoke and the novel substrate of charcoal and ash act as signals for an impending period of starvation requiring torpor. We therefore tested the hypothesis that the combined cues of smoke, a charcoal/ash substrate and food shortage will enhance torpor expression in a small forest-dwelling marsupial, the yellowfooted antechinus (Antechinus flavipes), because like other animals that live in fire-prone habitats they must effectively respond to fires to ensure survival. Activity and body temperature patterns of individuals in outdoor aviaries were measured under natural environmental conditions. All individuals were strictly nocturnal, but diurnal activity was observed shortly after smoke exposure. Overall, torpor in females was longer and deeper than that in males. Interestingly, while both males and females increased daily torpor duration during food restriction by >2-fold as anticipated, a combination of food restriction and smoke exposure on a charcoal/ash substrate further increased daily torpor duration by ∼2-fold in both sexes. These data show that this combination of cues for torpor induction is stronger than food shortage on its own. Our study provides significant new information on how a small forest-dwelling mammal responds to fire cues during and immediately after a fire and identifies a new, not previously recognised, regulatory mechanism for thermal biology in mammals

Physiological and behavioral responses of an arboreal mammal to smoke and charcoal-ash substrate.

The recent observation that torpor plays a key role in post-fire survival has been mainly attributed to the reduced food resources after fires. However, some of these adjustments can be facilitated or amplified by environmental changes associated with fires, such as the presence of a charcoal-ash substrate. In a previous experiment on a small terrestrial mammal the presence of charcoal and ash linked to food restriction intensified torpor use. However, whether fire cues also act as a trigger of torpor use when food is available and whether they affect other species including arboreal mammals remains elusive. To evaluate whether smoke, charcoal and ash can act as proximate triggers for an impending period of food shortage requiring torpor for mammals, we conducted an experiment on captive sugar gliders (Petaurus breviceps), a small, arboreal marsupial, housed in outside aviaries under different food regimes and natural ambient conditions. When food was available, fire simulation via exposure to smoke and charcoal-ash substrate caused a significant earlier start of activity and a significant decrease in resting body temperature. In contrast, only when food was withheld, did smoke and charcoal-ash exposure significantly enhance torpor depth and duration. Thus, our study not only provides evidence that fire simulation does affect arboreal and terrestrial species similarly, but also suggests that smoke and ash were presumably selected as cues for torpor induction because they indicate an impending lack of food

Structural Equation Modeling of Multiple-Indicator Multimethod-Multioccasion Data: A Primer

We provide a tutorial on how to analyze multiple-indicator multi-method (MM) longitudinal (multi-occasion, MO) data. Multiple-indicator MM-MO data presents specific challenges due to (1) different types of method effects, (2) longitudinal and cross-method measurement equivalence (ME) testing, (3) the question as to which process characterizes the longitudinal course of the construct under study, and (4) the issue of convergent validity versus method-specificity of different methods such as multiple informants. We present different models for multiple-indicator MM-MO data and discuss a modeling strategy that begins with basic single-method longitudinal confirmatory factor models and ends with more sophisticated MM-MO models. Our proposed strategy allows researchers to identify a well-fitting and possibly parsimonious model through a series of model comparisons. We illustrate our proposed MM-MO modeling strategy based on mother and father reports of inattention in a sample of N = 805 Spanish children

Examining Quadratic Relationships Between Traits and Methods in Two Multitrait-Multimethod Models

Multitrait-multimethod (MTMM) analysis is one of the most frequently employed methods to examine the validity of psychological measures. Confirmatory factor analysis (CFA) is a commonly used analytic tool for examining MTMM data through the specification of trait and method latent variables. Most contemporary CFA-MTMM models either do not allow estimating correlations between the trait and method factors or they are restricted to linear trait-method relationships. There is no theoretical reason why trait and method relationships should always be linear, and quadratic relationships are frequently proposed in the social sciences. In this article, we present two approaches for examining quadratic relations between traits and methods through extended latent difference and latent means CFA-MTMM models (Pohl et al., 2008; Pohl and Steyer, 2010). An application of the new approaches to a multi-rater study of the nine inattention symptoms of attention-deficit/hyperactivity disorder in children (N = 752) and the results of a Monte Carlo study to test the applicability of the models under a variety of data conditions are described

Applying and Interpreting Mixture Distribution Latent State-Trait Models

Latent state-trait (LST) models are commonly applied to determine the extent to which observed variables reflect trait-like versus state-like constructs. Mixture distribution LST (M-LST) models relax the assumption of population homogeneity made in traditional LST models, allowing researchers to identify subpopulations (latent classes) with differing trait- and state-like attributes. Applications of M-LST models are scarce, presumably because of the analysis complexity. We present a step-by-step tutorial for evaluating M-LST models based on an application to mother, father, and teacher reports of children’s inattention (n = 811). In the application, we found three latent classes for mother and father reports and four classes for teacher reports. All reporter solutions contained classes with very low, low, and moderate levels of inattention. The teacher solution also contained a class with high inattention. Comparable mother and father (but not teacher) classes exhibited similar levels of trait and state variance

Nano-technology and nano-toxicology

Rapid developments in nano-technology are likely to confer significant benefits on mankind. But, as with perhaps all new technologies, these benefits are likely to be accompanied by risks, perhaps by new risks. Nano-toxicology is developing in parallel with nano-technology and seeks to define the hazards and risks associated with nano-materials: only when risks have been identified they can be controlled. This article discusses the reasons for concern about the potential effects on health of exposure to nano-materials and relates these to the evidence of the effects on health of the ambient aerosol. A number of hypotheses are proposed and the dangers of adopting unsubstantiated hypotheses are stressed. Nano-toxicology presents many challenges and will need substantial financial support if it is to develop at a rate sufficient to cope with developments in nano-technology

Spin Liquid State in an Organic Mott Insulator with Triangular Lattice

$^{1}$H NMR and static susceptibility measurements have been performed in an organic Mott insulator with nearly isotropic triangular lattice, $\kappa$-(BEDT-TTF)$_{2}$Cu$_{2}$(CN)$_{3}$, which is a model system of frustrated quantum spins. The static susceptibility is described by the spin $S$ = 1/2 antiferromagnetic triangular-lattice Heisenberg model with the exchange constant $J$ $\sim$ 250 K. Regardless of the large magnetic interactions, the $^{1}$H NMR spectra show no indication of long-range magnetic ordering down to 32 mK, which is four-orders of magnitude smaller than $J$. These results suggest that a quantum spin liquid state is realized in the close proximity of the superconducting state appearing under pressure.Comment: 4 pages, 4 figure