ABSTRACT
Surviving changing climate conditions is particularly difficult for organisms such as insects that depend on environmental temperature to regulate their physiological functions. Insects are ...extremely threatened by global warming, since many do not have enough physiological tolerance even to survive continuous exposure to the current maximum temperatures experienced in their habitats. Here, we review literature on the physiological mechanisms that regulate responses to heat and provide heat tolerance in insects: (i) neuronal mechanisms to detect and respond to heat; (ii) metabolic responses to heat; (iii) thermoregulation; (iv) stress responses to tolerate heat; and (v) hormones that coordinate developmental and behavioural responses at warm temperatures. Our review shows that, apart from the stress response mediated by heat shock proteins, the physiological mechanisms of heat tolerance in insects remain poorly studied. Based on life‐history theory, we discuss the costs of heat tolerance and the potential evolutionary mechanisms driving insect adaptations to high temperatures. Some insects may deal with ongoing global warming by the joint action of phenotypic plasticity and genetic adaptation. Plastic responses are limited and may not be by themselves enough to withstand ongoing warming trends. Although the evidence is still scarce and deserves further research in different insect taxa, genetic adaptation to high temperatures may result from rapid evolution. Finally, we emphasize the importance of incorporating physiological information for modelling species distributions and ecological interactions under global warming scenarios. This review identifies several open questions to improve our understanding of how insects respond physiologically to heat and the evolutionary and ecological consequences of those responses. Further lines of research are suggested at the species, order and class levels, with experimental and analytical approaches such as artificial selection, quantitative genetics and comparative analyses.
ABSTRACT
Range shifts can rapidly create new areas of geographic overlap between formerly allopatric taxa and evidence is accumulating that this can affect species persistence. We review the emerging ...literature on the short‐ and long‐term consequences of these geographic range shifts. Specifically, we focus on the evolutionary consequences of novel species interactions in newly created sympatric areas by describing the potential (i) short‐term processes acting on reproductive barriers between species and (ii) long‐term consequences of range shifts on the stability of hybrid zones, introgression and ultimately speciation and extinction rates. Subsequently, we (iii) review the empirical literature on insects to evaluate which processes have been studied, and (iv) outline some areas that deserve increased attention in the future, namely the genomics of hybridisation and introgression, our ability to forecast range shifts and the impending threat from insect vectors and pests on biodiversity, human health and crop production. Our review shows that species interactions in de novo sympatric areas can be manifold, sometimes increasing and sometimes decreasing species diversity. A key issue that emerges is that climate‐induced hybridisations in insects are much more widespread than anticipated and that rising temperatures and increased anthropogenic disturbances are accelerating the process of species mixing. The existing evidence only shows the tip of the iceberg and we are likely to see many more cases of species mixing following range shifts in the near future.
Single‐ and few‐layer transition metal dichalcogenides have recently emerged as a new family of layered crystals with great interest , not only from the fundamental point of view, but also because of ...their potential application in ultrathin devices. Here the electronic properties of semiconducting MX2, where M =Mo or W and X = S or Se, are reviewed. Based on of density functional theory calculations, which include the effect of spin‐orbit interaction, the band structure of single‐layer, bilayer and bulk compounds is discussed. The band structure of these compounds is highly sensitive to elastic deformations, and it is reviewed how strain engineering can be used to manipulate and tune the electronic and optical properties of those materials. Further, the effect of disorder and imperfections in the lattice structure and their effect on the optical and transport properties of MX2 is discussed. The superconducting transition in these compounds, which has been observed experimentally, is analyzed, as well as the different mechanisms proposed so far to explain the pairing. Finally, a discussion on the excitonic effects which are present in these systems is included.
The recent isolation of atomically thin films of semiconducting transition metal dichalcogenides MX2(M = Mo, W and X = S, Se) has opened new opportunities for the application of two‐dimensional crystals in digital electronics, spintronics and optoelectronics devices. This family of semiconductors presents a number of remarkable features such as spin‐valley coupling, superconductivity, excitonic effects etc., which dramatically depend on their thickness (number of layers) and which are briefly reviewed in this article.
The muon tagging is an essential tool to distinguish between gamma and hadron-induced showers in wide field-of-view gamma-ray observatories. In this work, it is shown that an efficient muon tagging ...(and counting) can be achieved using a water Cherenkov detector with a reduced water volume and 4 PMTs, provided that the PMT signal spatial and time patterns are interpreted by an analysis based on machine learning (ML). The developed analysis has been tested for different shower and array configurations. The output of the ML analysis, the probability of having a muon in the WCD station, has been used to notably discriminate between gamma and hadron induced showers with
S
/
B
∼
4
for shower with energies
E
0
∼
1
TeV. Finally, for proton-induced showers, an estimator of the number of muons was built by means of the sum of the probabilities of having a muon in the stations. Resolutions about
20
%
and a negligible bias are obtained for vertical showers with
N
μ
>
10
.
Detecting and identifying pathogen bacteria is essential to ensure quality at all stages of the food chain and to diagnose and control microbial infections. Traditional detection methods, including ...those based on cell culturing, are tedious and time-consuming, and their further application in real samples generally implies more complex pretreatment steps. Even though state-of-the-art techniques for detecting microorganisms enable the quantification of very low concentrations of bacteria, to date it has been difficult to obtain successful results in real samples in a simple, reliable, and rapid manner. In this Article, we demonstrate that the label-free detection and identification of living bacteria in real samples can be carried out in a couple of minutes and in a direct, simple, and selective way at concentration levels as low as 6 colony forming units/mL (CFU) in complex matrices such as milk or 26 CFU/mL in apple juice where the pretreatment step of samples is extremely easy. We chose Escherichia coli (E. coli) CECT 675 cells as a model organism as a nonpathogenic surrogate for pathogenic E. coli O157:H7 to test the effectiveness of a potentiometric aptamer-based biosensor. This biosensor uses single-walled carbon nanotubes (SWCNT) as excellent ion-to-electron transducers and covalently immobilized aptamers as biorecognition elements. The selective aptamer−target interaction significantly changes the electrical potential, thus allowing for both interspecies and interstrain selectivity and enabling the direct detection of the target. This technique is therefore a powerful tool for the immediate identification and detection of microorganisms. We demonstrate the highly selective detection of living bacteria with an immediate linear response of up to 104 CFU/mL. The biosensor can be easily built and used, is regenerated without difficulty, and can be used at least five times with no loss in the minimum amount of detected bacteria.
Aims
To evaluate the influence of gestational diabetes mellitus on neonatal birthweight, macrosomia and weight discrepancy in twin neonates.
Methods
An observational retrospective study was ...performed. One hundred and six women with gestational diabetes and twin pregnancy and 166 twin controls who delivered viable fetuses > 24 weeks were included. Impact of maternal pre‐pregnancy BMI, smoking habit, method of conception, chorionicity, gestational age at delivery, mode of delivery and hypertensive complications were also analysed. The effect of maternal hyperglycaemia and metabolic control in gestational diabetes pregnancies was assessed.
Results
Gestational hypertension and pre‐eclampsia were significantly higher in the group with gestational diabetes (21.5% vs. 6.3%, P = 0.007 and 6.2% vs. 0%, P = 0.025). There were no differences in the incidence of macrosomia (5.7% vs. 7.2%, P = 0.803), large for gestational age (10.3% vs. 13.2%, P = 0.570), small for gestational age (10.3% vs. 12.0%, P = 0.701), severely small for gestational age (6.6% vs. 7.8%, P = 0.814) or weight discrepancy (20.6% vs. 15.2%, P = 0.320) in the group with gestational diabetes compared with twin pregnancies without diabetes. There were no differences when comparing insulin‐requiring gestational diabetes pregnancies and twins without diabetes for any of the neonatal weight outcomes. There was no relationship between third trimester HbA1c and neonatal birthweight or infant birthweight ratio.
Conclusion
Gestational diabetes did not increase the risk of macrosomia or weight discrepancy of twin newborns. Furthermore, glycaemic control did not influence the rate of any of the weight outcomes in our study population. In twin pregnancies, gestational diabetes was associated with a higher risk of gestational hypertension and pre‐eclampsia.
What's new?
Although gestational diabetes mellitus is clearly associated with macrosomia, its influence on weight outcome (including macrosomia, growth restriction and growth discrepancy) in twin pregnancies remains controversial.
In our study population, there were no differences in the incidence of macrosomia, large for gestational age, small for gestational age; severely small for gestational age or weight discrepancy between twin pregnancies complicated by gestational diabetes and controls. Neither were there differences when comparing insulin‐requiring gestational diabetes pregnancies and the control group for any of the neonatal weight outcomes. There was no relationship between third trimester HbA1c and neonatal birthweight or infant birthweight ratio.
Maternal mild hyperglycaemia may be physiological or ‘beneficial’ on twin pregnancies as a response for an increased demand of energy and nutrients, counterbalancing other known factors responsible for growth restriction in these pregnancies.
In this paper we report the first biosensor that is able to detect Staphylococcus aureus in real-time. A network of single-walled carbon nanotubes (SWCNTs) acts as an ion-to-electron potentiometric ...transducer and anti-S. aureus aptamers are the recognition element. Carbon nanotubes were functionalized with aptamers using two different approaches: (1) non-covalent adsorption of drop-casted pyrenil-modified aptamers onto the external walls of the SWCNTs; and (2) covalent bond formation between amine-modified aptamers and carboxylic groups previously introduced by oxidation at the ends of the SWCNTs. Both of these approaches yielded functional biosensors but there were large differences in the minimum detectable bacteria concentration and sensitivity values. With covalent functionalization, the minimum concentration detected was 8×102colony-forming units (CFU)/mL and the sensitivity was 0.36mV/Decade. With the non-covalent approach, the sensitivity was higher (1.52mV/Decade) but the minimum concentration detected was greatly affected (107CFU/mL). In both cases, potential as a function of Decade of bacteria concentration was linear. Functional biosensors were used to test real samples from freshly excised pig skin, contaminated with the target microorganism, as a surrogate for human skin.
Keeping the doctor away: An aptamer attached to an electrode coated with single‐walled carbon nanotubes interacts selectively with bacteria (see picture). The resulting electrochemical response is ...highly accurate and reproducible and starts at ultralow bacteria concentrations, thus providing a simple, selective method for pathogen detection.
The Mercedes water Cherenkov detector Assis, P.; Bakalová, A.; Barres de Almeida, U. ...
The European physical journal. C, Particles and fields,
10/2022, Letnik:
82, Številka:
10
Journal Article
Recenzirano
Odprti dostop
The concept of a small, single-layer water Cherenkov detector, with three photomultiplier tubes (PMTs), placed at its bottom in a
120
∘
star configuration (
Mercedes
Water Cherenkov Detector) is ...presented. The PMTs are placed near the lateral walls of the stations with an adjustable inclination and may be installed inside or outside the water volume. To illustrate the technical viability of this concept and obtain a first-order estimation of its cost, an engineering design was elaborated. The sensitivity of these stations to low energy Extensive Air Shower (EAS) electrons, photons and muons is discussed, both in compact and sparse array configurations. It is shown that the analysis of the intensity and time patterns of the PMT signals, using machine learning techniques, enables the tagging of muons, achieving an excellent gamma/hadron discrimination for TeV showers. This concept minimises the station production and maintenance costs, allowing for a highly flexible and fast installation. Mercedes Water Cherenkov Detectors (WCDs) are thus well-suited for use in high-altitude large gamma-ray observatories covering an extended energy range from the low energies, closing the gap between satellite and ground-based measurements, to very high energy regions, beyond the PeV scale.
Identifying environmental factors that structure intraspecific genetic diversity is of interest for both habitat preservation and biodiversity conservation. Recent advances in statistical and ...geographical genetics make it possible to investigate how environmental factors affect geographic organisation and population structure of molecular genetic diversity within species. Here we present a study on a common and wide ranging insect, the blue tailed damselfly Ischnuraelegans, which has been the target of many ecological and evolutionary studies. We addressed the following questions: (i) Is the population structure affected by longitudinal or latitudinal gradients?; (ii) Do geographic boundaries limit gene flow?; (iii) Does geographic distance affect connectivity and is there a signature of past bottlenecks?; (iv) Is there evidence of a recent range expansion and (vi) what is the effect of geography and climatic factors on population structure? We found low to moderate genetic sub-structuring between populations (mean F(ST) = 0.06, D(est) = 0.12), and an effect of longitude, but not latitude, on genetic diversity. No significant effects of geographic boundaries (e.g. water bodies) were found. F(ST)-and D(est)-values increased with geographic distance; however, there was no evidence for recent bottlenecks. Finally, we did not detect any molecular signatures of range expansions or an effect of geographic suitability, although local precipitation had a strong effect on genetic differentiation. The population structure of this small insect has probably been shaped by ecological factors that are correlated with longitudinal gradients, geographic distances, and local precipitation. The relatively weak global population structure and high degree of genetic variation within populations suggest that I. elegans has high dispersal ability, which is consistent with this species being an effective and early coloniser of new habitats.
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