A number of studies indicate that tropical arthropods should be particularly vulnerable to climate warming. If these predictions are realized, climate warming may have a more profound impact on the ...functioning and diversity of tropical forests than currently anticipated. Although arthropods comprise over two-thirds of terrestrial species, information on their abundance and extinction rates in tropical habitats is severely limited. Here we analyze data on arthropod and insectivore abundances taken between 1976 and 2012 at two midelevation habitats in Puerto Rico’s Luquillo rainforest. During this time, mean maximum temperatures have risen by 2.0 °C. Using the same study area and methods employed by Lister in the 1970s, we discovered that the dry weight biomass of arthropods captured in sweep samples had declined 4 to 8 times, and 30 to 60 times in sticky traps. Analysis of long-term data on canopy arthropods and walking sticks taken as part of the Luquillo Long-Term Ecological Research program revealed sustained declines in abundance over two decades, as well as negative regressions of abundance on mean maximum temperatures. We also document parallel decreases in Luquillo’s insectivorous lizards, frogs, and birds. While El Niño/Southern Oscillation influences the abundance of forest arthropods, climate warming is the major driver of reductions in arthropod abundance, indirectly precipitating a bottom-up trophic cascade and consequent collapse of the forest food web.
Microchromosomes, once considered unimportant shreds of the chicken genome, are gene-rich elements with a high GC content and few transposable elements. Their origin has been debated for decades. We ...used cytological and whole-genome sequence comparisons, and chromosome conformation capture, to trace their origin and fate in genomes of reptiles, birds, and mammals. We find that microchromosomes as well as macrochromosomes are highly conserved across birds and share synteny with single small chromosomes of the chordate amphioxus, attesting to their origin as elements of an ancient animal genome. Turtles and squamates (snakes and lizards) share different subsets of ancestral microchromosomes, having independently lost microchromosomes by fusion with other microchromosomes or macrochromosomes. Patterns of fusions were quite different in different lineages. Cytological observations show that microchromosomes in all lineages are spatially separated into a central compartment at interphase and during mitosis and meiosis. This reflects higher interaction between microchromosomes than with macrochromosomes, as observed by chromosome conformation capture, and suggests some functional coherence. In highly rearranged genomes fused microchromosomes retain most ancestral characteristics, but these may erode over evolutionary time; surprisingly, de novo microchromosomes have rapidly adopted high interaction. Some chromosomes of early-branching monotreme mammals align to several bird microchromosomes, suggesting multiple microchromosome fusions in a mammalian ancestor. Subsequently, multiple rearrangements fueled the extraordinary karyotypic diversity of therian mammals. Thus, microchromosomes, far from being aberrant genetic elements, represent fundamental building blocks of amniote chromosomes, and it is mammals, rather than reptiles and birds, that are atypical.
The adaptive significance of acute pain (to withdraw from tissue-damaging or potentially tissue-damaging external stimuli, and to enhance the salience of the stimulus resulting in escape and ...avoidance learning) and tonic pain (to enforce recuperation by punishing movement) are well-accepted 1. Pain researchers, however, generally assert that chronic pain has no adaptive significance, representing instead a pathophysiological state. This belief was recently challenged by the observation 2 that nociceptive sensitization caused by a chronic pain-producing injury reduced predation risk in squid (Doryteuthis pealeii). In that study, injury to an arm (removal of the tip with a scalpel) 6 hours prior led to increased targeting by black sea bass, resulting in decreased survival of the squid in a 30-minute trial featuring free interaction between predator and prey. The surprising finding was that anesthesia during surgery, preventing the chronic nociceptor sensitization associated with such injuries, led to even lower probability of survival. That is, the likely presence of pain increased apparent fitness, and the authors concluded that the chronic pain state and its associated nociceptive sensitization represented an adaptive function. Pain-induced defensive behaviors affecting fitness have also been reported in crustaceans (Gammarus fossarum) 3. It is, however, currently unknown whether this may also be true in any other species, including in Mammalia.
Studies in invertebrates suggest that the adaptive value of chronic pain may lie in producing hypervigilance to predation. Lister et al. test the hypothesis that chronic pain may produce hypervigilance in mice. Using an octagonal maze, they show that mouse avoidance of fox urine is increased after experimental nerve injury producing chronic pain.
Summary
Human factors in anaesthesia were first highlighted by the publication of the Anaesthetists Non‐Technical Skills Framework, and since then an awareness of their importance has gradually ...resulted in changes in routine clinical practice. This review examines recent literature around human factors in anaesthesia, and highlights recent national reports and guidelines with a focus on team working, communication, situation awareness and human error. We highlight the importance of human factors in modern anaesthetic practice, using the example of complex trauma.
Cs2LiYCl6:Ce (CLYC) has been demonstrated to be sensitive to thermal neutrons via the 6Li(n, α)t reaction, and recently to fast neutrons via the 35Cl(n,p) reaction. The scintillation properties of ...CLYC have been investigated in more detail to further understand its capabilities. Pulses from thermal neutron, fast neutron, and γ-ray induced excitations were captured, digitized over a 16μs time range, and analyzed to identify the scintillation mechanisms responsible for the observed shapes. Additionally, the timing resolutions of CLYC crystals of different sizes were measured in coincidence with a fast CeBr3 scintillator. The effect of high count rates on fast neutron energy resolution and pulse-shape discrimination was investigated up to 45kHz.
The encoding of noxious stimuli into action potential firing is largely mediated by nociceptive free nerve endings. Tissue inflammation, by changing the intrinsic properties of the nociceptive ...endings, leads to nociceptive hyperexcitability, and thus to the development of inflammatory pain. Here, we showed that tissue inflammation-induced activation of the mammalian target of rapamycin complex 2 (mTORC2) triggers changes in the architecture of nociceptive terminals and leads to inflammatory pain. Pharmacological activation of mTORC2 induced elongation and branching of nociceptor peripheral endings and caused long-lasting pain hypersensitivity. Conversely, nociceptor-specific deletion of the mTORC2 regulatory protein, Rictor, prevented inflammation-induced elongation and branching of cutaneous nociceptive fibers and attenuated inflammatory pain hypersensitivity. Computational modelling demonstrated that mTORC2-mediated structural changes in the nociceptive terminal tree are sufficient to increase the excitability of nociceptors. Targeting mTORC2 using a single injection of antisense oligonucleotide against Rictor provided long-lasting alleviation of inflammatory pain hypersensitivity. Collectively, we showed that tissue inflammation-induced activation of mTORC2 causes structural plasticity of nociceptive free nerve endings in the epidermis and inflammatory hyperalgesia, representing a therapeutic target for inflammatory pain.
Repeated or prolonged, but not short-term, general anesthesia during the early postnatal period causes long-lasting impairments in memory formation in various species. The mechanisms underlying ...long-lasting impairment in cognitive function are poorly understood. Here, we show that repeated general anesthesia in postnatal mice induces preferential apoptosis and subsequent loss of parvalbumin-positive inhibitory interneurons in the hippocampus. Each parvalbumin interneuron controls the activity of multiple pyramidal excitatory neurons, thereby regulating neuronal circuits and memory consolidation. Preventing the loss of parvalbumin neurons by deleting a proapoptotic protein, mitochondrial anchored protein ligase (MAPL), selectively in parvalbumin neurons rescued anesthesia-induced deficits in pyramidal cell inhibition and hippocampus-dependent long-term memory. Conversely, partial depletion of parvalbumin neurons in neonates was sufficient to engender long-lasting memory impairment. Thus, loss of parvalbumin interneurons in postnatal mice following repeated general anesthesia critically contributes to memory deficits in adulthood.
Conservation laws are deeply related to any symmetry present in a physical system
. Analogously to electrons in atoms exhibiting spin symmetries
, it is possible to consider neutrons and protons in ...the atomic nucleus as projections of a single fermion with an isobaric spin (isospin) of t = 1/2 (ref.
). Every nuclear state is thus characterized by a total isobaric spin T and a projection T
-two quantities that are largely conserved in nuclear reactions and decays
. A mirror symmetry emerges from this isobaric-spin formalism: nuclei with exchanged numbers of neutrons and protons, known as mirror nuclei, should have an identical set of states
, including their ground state, labelled by their total angular momentum J and parity π. Here we report evidence of mirror-symmetry violation in bound nuclear ground states within the mirror partners strontium-73 and bromine-73. We find that a J
= 5/2
spin assignment is needed to explain the proton-emission pattern observed from the T = 3/2 isobaric-analogue state in rubidium-73, which is identical to the ground state of strontium-73. Therefore the ground state of strontium-73 must differ from its J
= 1/2
mirror bromine-73. This observation offers insights into charge-symmetry-breaking forces acting in atomic nuclei.
The carpometric characteristics, major antioxidant components, and antioxidant activity of three commercial New Zealand tomato cultivars, Excell, Tradiro, and Flavourine were studied in a greenhouse ...over a period of 8 months. The variations in the solar radiations received, temperature inside the greenhouse, and changes in the fruit load over the study period significantly (
P
<
0.05
) affected the antioxidant components of tomatoes. The total phenolics and antioxidant activity in the three cultivars ranged from 169 to 579
mg gallic acid equivalents/100
g dry matter (DM) and 1684 to 3340
μ
m TEAC/100
g DM, respectively, during the study period. The mean total phenolics and antioxidant activity of the three cultivars was 62% and 39% higher, respectively, in summer (December–February) than in spring (September–November). The ascorbic acid and lycopene content of the three cultivars varied between 165 and 252
mg/100
g DM and from 19 to 73
mg/100
g DM, respectively, during the study period. The mean lycopene content of the three cultivars was 31% lower in the summer months than at other times of the study. This study indicates that the antioxidant components of tomatoes can vary considerably with the changes in environmental conditions within the greenhouse and the levels of antioxidants in greenhouse grown tomatoes could be elevated throughout the growing season by modifying the environmental conditions inside the greenhouses.
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