81 research outputs found
Experimental reversion of the optimal quantum cloning and flipping processes
The quantum cloner machine maps an unknown arbitrary input qubit into two
optimal clones and one optimal flipped qubit. By combining linear and
non-linear optical methods we experimentally implement a scheme that, after the
cloning transformation, restores the original input qubit in one of the output
channels, by using local measurements, classical communication and feedforward.
This significant teleportation-like method demonstrates how the information is
preserved during the cloning process. The realization of the reversion process
is expected to find useful applications in the field of modern multi-partite
quantum cryptography.Comment: 10 pages, 3 figure
Vegetation maps based on remote sensing are informative predictors of habitat selection of grassland birds across a wetness gradient
Vegetation is a major environmental factor influencing habitat selection in bird species. High resolution mapping of vegetation cover is essential to model the distribution of populations and improve the management of breeding habitats. However, the task is challenging for grassland birds because microhabitat variations relevant at the territory scale cannot be measured continuously over large areas to delineate areas of higher suitability. Remote sensing may help to circumvent this problem. We addressed this issue by using two methods. We (i) mapped the continuous Ellenberg index of moisture and (ii) identified 5 vegetation classes distributed accross the wetness gradient. These two methods produced consistent output maps, but they also provided more information about vegetation structure, and possibly trophic resources. In spite of the apprent uniformity of meadows, our data show that birds do not settle randomly along the moisture and vegetation gradients. Overall birds tend to avoid the driest vegetation classes, i.e. the highest grounds. Thus, vegetation maps based on remote sensing could be valuable tools to study habitat selection and niche partition in grassland bird communities. It is also a valuable tool for conservation and habitat management
Olfactory and visual species recognition in newts and their role in hybridization
Mating patterns between hybridizing taxa are often conditional to the mechanisms underlying species recognition. During mate choice, individuals often assess information displayed by potential mates on several sensory channels. The reliance on more than one modality is particularly expected whenever transmission conditions are variable or signals subject to wear. Determining the sensory bases of species recognition is, thus, crucial to assess the effect of the signalling environment on the hybridization process between species where mate choice occurs. We addressed this issue in two newt species, Lissotriton helveticus and L. vulgaris, that hybridize and breed in aquatic habitats disturbed by various natural processes. We measured visual and olfactory preferences in males and females. Visual and olfactory recognition was detected in L. helveticus males and L. vulgaris females. In contrast, we observed limited olfactory recognition in L. helveticus females and no evidence of recognition at all in L. vulgaris males. In addition, one single variable, body size, strongly influenced female preference. Ecological factors modulating visual signalling conditions and the body size ratio in males are, thus, likely to influence the probability of heterospecific mating. This study highlights the need to consider more largely environmental factors affecting communication in the hybridization process
UV wavelengths experienced during development affect larval newt visual sensitivity and predation efficiency
We experimentally investigated the influence of developmental plasticity of ultraviolet (UV) visual sensitivity on predation efficiency of the larval smooth newt, Lissotriton vulgaris. We quantified expression of SWS1 opsin gene (UV-sensitive protein of photoreceptor cells) in the retinas of individuals who had developed in the presence (UV+) or absence (UV-) of UV light (developmental treatments), and tested their predation efficiency under UV+ and UV- light (testing treatments). We found that both SWS1 opsin expression and predation efficiency were significantly reduced in the UV- developmental group. Larvae in the UV- testing environment displayed consistently lower predation efficiency regardless of their developmental treatment. These results prove for the first time, we believe, functional UV vision and developmental plasticity of UV sensitivity in an amphibian at the larval stage. They also demonstrate that UV wavelengths enhance predation efficiency and suggest that the magnitude of the behavioural response depends on retinal properties induced by the developmental lighting environment
Within-Host Speciation of Malaria Parasites
BACKGROUND: Sympatric speciation—the divergence of populations into new species in absence of geographic barriers to hybridization—is the most debated mode of diversification of life forms. Parasitic organisms are prominent models for sympatric speciation, because they may colonise new hosts within the same geographic area and diverge through host specialization. However, it has been argued that this mode of parasite divergence is not strict sympatric speciation, because host shifts likely cause the sudden effective isolation of parasites, particularly if these are transmitted by vectors and therefore cannot select their hosts. Strict sympatric speciation would involve parasite lineages diverging within a single host species, without any population subdivision. METHODOLOGY/PRINCIPAL FINDINGS: Here we report a case of extraordinary divergence of sympatric, ecologically distinct, and reproductively isolated malaria parasites within a single avian host species, which apparently occurred without historical or extant subdivision of parasite or host populations. CONCLUSIONS/SIGNIFICANCE: This discovery of within-host speciation changes our current view on the diversification potential of malaria parasites, because neither geographic isolation of host populations nor colonization of new host species are any longer necessary conditions to the formation of new parasite species
Hybridization but No Evidence for Backcrossing and Introgression in a Sympatric Population of Great Reed Warblers and Clamorous Reed Warblers
Hybridization is observed frequently in birds, but often it is not known whether the hybrids are fertile and if backcrossing occurs. The breeding ranges of the great reed warbler (Acrocephalus arundinaceus) and the clamorous reed warbler (A. stentoreus) overlap in southern Kazakhstan and a previous study has documented hybridization in a sympatric population. In the present study, we first present a large set of novel microsatellite loci isolated and characterised in great reed warblers. Secondly, we evaluate whether hybridization in the sympatric breeding population has been followed by backcrossing and introgression
Value-Chain Wide Food Waste Management: A Systematic Literature Review
© 2019, Springer Nature Switzerland AG. The agriculture value chain, from farm to fork, has received enormous attention because of its key role in achieving United Nations Global Challenges Goals. Food waste occurs in many different forms and at all stages of the food value chain, it has become a worldwide issue that requires urgent actions. However, the management of food waste has been traditionally segmented and in an isolated manner. This paper reviews existing work that has been done on food waste management in literature by taking a holistic approach, in order to identify the causes of food waste, food waste prevention strategies, and elicit recommendations for future work. A five step systematic literature review has been adopted for a thorough examination of the existing research on the topic and new insights have been obtained. The findings suggest that the main sources of food waste include food overproduction and surplus, food waste caused by processing, logistical inconsistencies, and households. Main food waste prevention strategies have been revealed in this paper include policy solutions, packaging solutions, date-labelling solutions, logistics solutions, changing consumers’ behaviours, and reuse and redistribution solutions. Future research directions such as using value chain models to reduce food waste and forecasting food waste have been identified in this paper. This study makes a contribution to the extant literature in the field of food waste management by discovering main causes of food waste in the value chain and eliciting prevention strategies that can be used to reduce/eliminate relevant food waste
Ecological character displacement in the face of gene flow: Evidence from two species of nightingales
<p>Abstract</p> <p>Background</p> <p>Ecological character displacement is a process of phenotypic differentiation of sympatric populations caused by interspecific competition. Such differentiation could facilitate speciation by enhancing reproductive isolation between incipient species, although empirical evidence for it at early stages of divergence when gene flow still occurs between the species is relatively scarce. Here we studied patterns of morphological variation in sympatric and allopatric populations of two hybridizing species of birds, the Common Nightingale (<it>Luscinia megarhynchos</it>) and the Thrush Nightingale (<it>L. luscinia</it>).</p> <p>Results</p> <p>We conducted principal component (PC) analysis of morphological traits and found that nightingale species converged in overall body size (PC1) and diverged in relative bill size (PC3) in sympatry. Closer analysis of morphological variation along geographical gradients revealed that the convergence in body size can be attributed largely to increasing body size with increasing latitude, a phenomenon known as Bergmann's rule. In contrast, interspecific interactions contributed significantly to the observed divergence in relative bill size, even after controlling for the effects of geographical gradients. We suggest that the divergence in bill size most likely reflects segregation of feeding niches between the species in sympatry.</p> <p>Conclusions</p> <p>Our results suggest that interspecific competition for food resources can drive species divergence even in the face of ongoing hybridization. Such divergence may enhance reproductive isolation between the species and thus contribute to speciation.</p
Introgression and rapid species turnover in sympatric damselflies
<p>Abstract</p> <p>Background</p> <p>Studying contemporary hybridization increases our understanding of introgression, adaptation and, ultimately, speciation. The sister species <it>Ischnura elegans </it>and <it>I. graellsii </it>(Odonata: Coenagrionidae) are ecologically, morphologically and genetically similar and hybridize. Recently, <it>I. elegans </it>has colonized northern Spain, creating a broad sympatric region with <it>I. graellsii</it>. Here, we review the distribution of both species in Iberia and evaluate the degree of introgression of <it>I. graellsii </it>into <it>I. elegans </it>using six microsatellite markers (442 individuals from 26 populations) and five mitochondrial genes in sympatric and allopatric localities. Furthermore, we quantify the effect of hybridization on the frequencies of the genetically controlled colour polymorphism in females of both species.</p> <p>Results</p> <p>In a principal component analysis of the microsatellite data, the first two principal components summarised almost half (41%) of the total genetic variation. The first axis revealed a clear separation of <it>I. graellsii </it>and <it>I</it>. <it>elegans </it>populations, while the second axis separated <it>I. elegans </it>populations. Admixture analyses showed extensive hybridization and introgression in <it>I. elegans </it>populations, consistent with <it>I. elegans </it>backcrosses and occasional F<sub>1</sub>-hybrids, suggesting hybridization is on-going. More specifically, approximately 58% of the 166 Spanish <it>I. elegans </it>individuals were assigned to the <it>I. elegans </it>backcross category, whereas not a single of those individuals was assigned to the backcross with <it>I. graellsii</it>. The mitochondrial genes held little genetic variation, and the most common haplotype was shared by the two species.</p> <p>Conclusions</p> <p>The results suggest rapid species turnover in sympatric regions in favour of <it>I. elegans</it>, corroborating previous findings that <it>I. graellsii </it>suffers a mating disadvantage in sympatry with <it>I. elegans</it>. Examination of morph frequency dynamics indicates that hybridization is likely to have important implications for the maintenance of multiple female morphs, in particular during the initial period of hybridization.</p
Vocal Communications and the Maintenance of Population Specific Songs in a Contact Zone
Bird song has been hypothesized to play a role in several important aspects of the biology of songbirds, including the generation of taxonomic diversity by speciation; however, the role that song plays in speciation within this group may be dependent upon the ability of populations to maintain population specific songs or calls in the face of gene flow and external cultural influences. Here, in an exploratory study, we construct a spatially explicit model of population movement to examine the consequences of secondary contact of populations singing distinct songs. We concentrate on two broad questions: 1) will population specific songs be maintained in a contact zone or will they be replaced by shared song, and 2) what spatial patterns in the distribution of songs may result from contact? We examine the effects of multiple factors including song-based mating preferences and movement probabilities, oblique versus paternal learning of song, and both cultural and genetic mutations. We find a variety of conditions under which population specific songs can be maintained, particularly when females have preferences for their population specific songs, and we document many distinct patterns of song distribution within the contact zone, including clines, banding, and mosaics
- …