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1.
Cell Rep Phys Sci ; 3(2)2022 Feb 16.
Article in English | MEDLINE | ID: mdl-35265868

ABSTRACT

Preventing spontaneous crystallization of supersaturated solutions by additives is of critical interest to successful process design and implementation, with numerous applications in chemical, pharmaceutical, medical, pigment, and food industries, but challenges remain in laboratory and industry settings and fundamental understanding is lacking. When copresented with antifreeze proteins (AFPs), otherwise spontaneously crystallizing osmolytes are maintained at high supersaturations for months in over-wintering organisms. Thus, we here explore the inhibition phenomenon by AFPs, using persistent crystallization of a common sugar alcohol, D-mannitol, as a case study. We report experimentally that DAFP1, an insect AFP, completely inhibits D-mannitol nucleation. Computer simulations reveal a new mechanism for crystallization inhibition where the population of the crystal-forming conformers are selectively bound and randomized in solution by hydrogen bonding to the protein surface. These results highlight the advantages of using natural polymers to address crystallization inhibition challenges and suggest new strategies in controlling the nucleation processes.

2.
Sensors (Basel) ; 20(10)2020 May 25.
Article in English | MEDLINE | ID: mdl-32466175

ABSTRACT

In recent years, artificial intelligence (AI) has started to manifest itself at an unprecedented pace. With highly sophisticated capabilities, AI has the potential to dramatically change our cities and societies. Despite its growing importance, the urban and social implications of AI are still an understudied area. In order to contribute to the ongoing efforts to address this research gap, this paper introduces the notion of an artificially intelligent city as the potential successor of the popular smart city brand-where the smartness of a city has come to be strongly associated with the use of viable technological solutions, including AI. The study explores whether building artificially intelligent cities can safeguard humanity from natural disasters, pandemics, and other catastrophes. All of the statements in this viewpoint are based on a thorough review of the current status of AI literature, research, developments, trends, and applications. This paper generates insights and identifies prospective research questions by charting the evolution of AI and the potential impacts of the systematic adoption of AI in cities and societies. The generated insights inform urban policymakers, managers, and planners on how to ensure the correct uptake of AI in our cities, and the identified critical questions offer scholars directions for prospective research and development.


Subject(s)
Artificial Intelligence , Natural Disasters , Pandemics , Cities , Humans , Prospective Studies
3.
Gen Comp Endocrinol ; 162(3): 313-8, 2009 Jul.
Article in English | MEDLINE | ID: mdl-19371744

ABSTRACT

Dependent young are often easy targets for predators, so for many parent vertebrates, responding to offspring-directed threats is a fundamental part of reproduction. We tested the parental adrenocortical response of the endangered black-capped vireo (Vireo atricapilla) and the common white-eyed vireo (V. griseus) to acute and chronic threats to their offspring. Like many open-nesting birds, our study species experience high offspring mortality. Parents responded behaviorally to a predator decoy or human 1-2m from their nests, but, in contrast to similar studies of cavity-nesting birds, neither these acute threats nor chronic offspring-directed threats altered plasma corticosterone concentrations of parents. Although parents in this study showed no corticosterone response to offspring-directed threats, they always increased corticosterone concentrations in response to capture. To explain these results, we propose that parents perceive their risk of nest-associated death differently depending on nest type, with cavity-nesting adults perceiving greater risk to themselves than open-nesters that can readily detect and escape from offspring-directed threats. Our results agree with previous studies suggesting that the hypothalamic-pituitary-adrenal axis, a major physiological mechanism for coping with threats to survival, probably plays no role in coping with threats to offspring when risks to parents and offspring are not correlated. We extend that paradigm by demonstrating that nest style may influence how adults perceive the correlation between offspring-directed and self-directed threats.


Subject(s)
Adrenal Cortex Hormones/blood , Hypothalamo-Hypophyseal System/physiology , Nesting Behavior/physiology , Passeriformes/physiology , Pituitary-Adrenal System/physiology , Predatory Behavior , Stress, Psychological/blood , Animals , Corticosterone/blood , Passeriformes/blood
4.
Proc Biol Sci ; 276(1658): 961-9, 2009 Mar 07.
Article in English | MEDLINE | ID: mdl-19129135

ABSTRACT

Anthropogenic or natural disturbances can have a significant impact on wild animals. Therefore, understanding when, how and what type of human and natural events disturb animals is a central problem in wildlife conservation. However, it can be difficult to identify which particular environmental stressor affects an individual most. We use heart rate telemetry to quantify the energy expenditure associated with different types of human-mediated and natural disturbances in a breeding passerine, the white-eyed vireo (Vireo griseus). We fitted 0.5g heart rate transmitters to 14 male vireos and continuously recorded heart rate and activity for two days and three nights on a military installation. We calibrated heart rate to energy expenditure for five additional males using an open-flow, push-through respirometry system showing that heart rate predicted 74 per cent of energy expenditure. We conducted standardized disturbance trials in the field to experimentally simulate a natural stressor (predator presence) and two anthropogenic stressors. Although birds initially showed behavioural and heart rate reactions to some disturbances, we could not detect an overall increase in energy expenditure during 1- or 4-hours disturbances. Similarly, overall activity rates were unaltered between control and experimental periods, and birds continued to perform parental duties despite the experimental disturbances. We suggest that vireos quickly determined that disturbances were non-threatening and thus showed no (costly) physiological response. We hypothesize that the lack of a significant response to disturbance in vireos is adaptive and may be representative of animals with fast life histories (e.g. short lifespan, high reproductive output) so as to maximize energy allocation to reproduction. Conversely, we predict that energetic cost of human-mediated disturbances will be significant in slow-living animals.


Subject(s)
Energy Metabolism , Songbirds/physiology , Animals , Human Activities , Male , Paternal Behavior
5.
Ecology ; 88(11): 2729-35, 2007 Nov.
Article in English | MEDLINE | ID: mdl-18051640

ABSTRACT

Many young birds on the Arctic tundra are confronted by a challenging task: they must molt their feathers and accumulate fat stores for the autumn migration before climatic conditions deteriorate. Our understanding of the costs and constraints associated with these stages is extremely limited. We investigated post-juvenal molt and premigratory fattening in free-ranging juvenile White-crowned Sparrows (Zonotrichia leucophrys gambelii) on the Arctic tundra. We found evidence for trade-offs between premigratory fat accumulation and molt: heavily molting birds had significantly less fat. Birds increased the rate of fat accumulation as the season progressed, but we found no evidence of a similar increase in rate of molt. Using a controlled captive study to isolate the energetic costs of body feather replacement, we found no difference in fat or size-corrected mass of birds actively growing body feathers as compared to controls. Molting birds, however, consumed 17% more food than controls, suggesting a significant cost of body feather growth. Our results provide evidence of significant costs, constraints, and trade-offs associated with post-juvenal molt and premigratory fat accumulation in young Arctic birds.


Subject(s)
Adipose Tissue/anatomy & histology , Animal Migration/physiology , Energy Intake/physiology , Molting/physiology , Sparrows/physiology , Adipose Tissue/growth & development , Animals , Arctic Regions , Feathers/growth & development , Female , Male , Nutritional Requirements , Time Factors
6.
Proc Biol Sci ; 271 Suppl 6: S498-500, 2004 Dec 07.
Article in English | MEDLINE | ID: mdl-15801615

ABSTRACT

The steroid hormone testosterone regulates aggressive behaviour in many vertebrates and is important for territorial defence among males of the same species. However, its role in mediating interspecific competition, and ultimately species distributions, is unknown. We show that testosterone may influence the geographical replacement of one species by another. Townsend's warblers (Dendroica townsendi) have replaced hermit warblers (D. occidentalis) over a vast portion of their historical range, partly because Townsend's males are more aggressive than hermit males and outcompete them for territories in areas of sympatry. We report differences in plasma androgen levels that parallel these aggressive asymmetries and the historical pattern of species replacement between Townsend's and hermits. Using hybrids, we provide evidence that these hormonal differences are partially genetically based and thus may have evolved through sexual selection during Pleistocene glacial maxima. Hormone-behaviour mechanisms can therefore have important effects on species distributions and can even influence the pathways underlying extinction.


Subject(s)
Aggression , Androgens/blood , Demography , Hybridization, Genetic , Songbirds/metabolism , Territoriality , Analysis of Variance , Animals , Geography , Male , Population Dynamics , Radioimmunoassay , Selection, Genetic , Songbirds/genetics , Songbirds/physiology , Species Specificity , Washington
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