Revision of type and non-type material assigned to the genus Orthocladius by Goetghebuer (1940–1950), deposited in the Royal Belgian Institute of Natural Sciences (Diptera: Chironomidae)

Selected type and non-type material belonging to the genus Orthocladius van der Wulp, 1874 (Diptera: Chironomidae) sensu G OETGHEBUER (1940\u20131950), deposited in the Royal Belgian Institute of Natural Sciences (RBINS), originally comprising specimens dry pinned or stored in isinglass, were mounted on microscope slides and re-examined. Other chironomids present in the RBINS collection belonging to other genera were also examined. Fifty slides were prepared and identified to species, or to generic level when the condition of the specimens did not allow species identification. The following types, representing taxa formerly considered as nomina dubia, were examined and the concerned species are stated here as valid: Georthocladius collarti (Goetghebuer, 1941) comb. nov., Georthocladius scaturiginis (Goetghebuer, 1940) comb. nov., Lapposmittia succinea (Goetghebuer, 1942) comb. nov., Orthocladius (Euorthocladius) tolleti Goetghebuer, 1944 (new subgenus placement), Orthocladius (Orthocladius) timoni Goetghebuer & Timon-David, 1939, Pseudorthocladius hockaiensis (Goetghebuer, 1933). Orthocladius (Orthocladius) mitisi Goetghebuer, 1938, previously stated as junior synonym of Orthocladius (Orthocladius) glabripennis (Goetghebuer, 1921), is reinstated as valid species. The following new synonyms are proposed: Georthocladius (Georthocladius) collarti = Parachaetocladius retezati Albu, 1972: 19, syn. nov.; Cricotopus (Paratrichocladius) rufiventris (Meigen, 1830) = Orthocladius franzi Goetghebuer, 1949, syn. nov.; Cricotopus (Paratricho-cladius) skirwithensis Edwards, 1929 = Orthocladius nigritus Goetghebuer, 1938, syn. nov. = Paratrichocladius spiesi Ashe & O\u2019Connor, 2012; Hydrobaenus distylus (Potthast, 1914) = Orthocladius antennalis Goetghebuer, 1944, syn. nov. Lecto-types of Orthocladius collarti Goetghebuer, 1941, Orthocladius antennalis Goetghebuer, 1944, Orthocladius timoni Goetghebuer & Timon-David, 1939, and Orthocladius hockaiensis Goetghebuer, 1933 are designated. Non-type material assigned to Orthocladius was also mounted on slides and identified. Although a list of the non-Orthocladius taxa is also provided, no taxonomic changes are proposed for the latter

Early amniotomy after cervical ripening for induction of labor: a systematic review and meta-analysis of randomized controlled trials

OBJECTIVE DATA: Timing of artificial rupture of membranes (ie, amniotomy) in induction of labor is controversial, because it has been associated not only with shorter labors, but also with fetal nonreassuring testing, at times necessitating cesarean delivery. The aim of this systematic review and metaanalysis of randomized trials was to evaluate the effectiveness of early amniotomy vs late amniotomy or spontaneous rupture of membranes after cervical ripening. STUDY: The search was conducted with the use of electronic databases from inception of each database through February 2019. Review of articles included the abstracts of all references that were retrieved from the search. STUDY APPRAISAL AND SYNTHESIS METHODS: Selection criteria included randomized clinical trials that compared early amniotomy vs control (ie, late amniotomy or spontaneous rupture of membranes) after cervical ripening with either Foley catheter or prostaglandins at any dose. The primary outcome was the incidence of cesarean delivery. The summary measures were reported as summary relative risk with 95% of confidence interval with the use of the random effects model of DerSimonian and Laird. RESULTS: Four trials that included 1273 women who underwent cervical ripening with either Foley catheter or prostaglandins and then were assigned randomly to either early amniotomy, late amniotomy, or spontaneous rupture of membranes (control subjects) were included in the review. Women who were assigned randomly to early amniotomy had a similar risk of cesarean delivery (31.1% vs 30.9%; relative risk, 1.05; 95% confidence interval, 0.71-1.56) compared with control subjects and had a shorter interval from induction to delivery of approximately 5 hours (mean difference, -4.95 hours; 95% confidence interval, -8.12 to -1.78). Spontaneous vaginal delivery was also reduced in the early amniotomy group, but only 1 of the included trials reported this outcome (67.5% vs 69.1%; relative risk, 0.78; 95% confidence interval, 0.66-0.93). No between-group differences were reported in the other obstetrics or perinatal outcomes. CONCLUSION: After cervical ripening, routine early amniotomy does not increase the risk of cesarean delivery and reduces the interval from induction to delivery

Biotic and abiotic factors affecting the microbiota of Chrysomelidae inhabiting wetland vegetation

A subject of particular interest concerns the understanding of which biotic and/or abiotic factors shape the insect’s microbiota composition and diversity. In this study, we focus our attention on the microbiota associated with leaf beetles (Coleoptera: Chrysomelidae) inhabiting a freshwater wetland in Northern Italy for investigating which factors shape it in this peculiar environment. A DNA metabarcoding approach targeting the 16S rRNA has been used to characterize the bacteria associated with seven leaf beetles species living in different zones of the wetland (trees/shrubs, meadow and emergent vegetation zones). The obtained results suggest that three factors potentially affecting microbiota diversity and composition are species membership in the first place, then living zone in the wetland and sex. Within the studied species, males were found possibly more prone to acquire bacteria from the surrounding environment, while females’ microbiota of most of the species resulted dominated by symbiotic bacteria (reproductive manipulators, e.g. Wolbachia, or other symbionts with functional roles in the species, e.g. Candidatus Macropleicola in Donacia genus). The present study, even if based on a limited sample size, contributed to exploring the factors affecting the composition and diversity of bacteria associated with Chrysomelidae

The microbiota of Idaea inquinata developing on dry herbs

Idaea inquinata (Scopoli) (Lepidoptera: Geometridae, Idaeini) is a potential pest of stored food, mainly dry herbs. In this study, the role of diet in the shaping of the I. inquinata-associated bacterial community was investigated and its impact on insect performance (i.e., proportion of adult emergence and duration of postembryonic development). Larvae were reared on three diets with different nutritional compositions: (1) Matricaria chamomilla L. flowers, (2) Angelica archangelica L. roots, and (3) artificial diet. A DNA metabarcoding approach targeting V1-V2 and V4 regions of the bacterial 16S rRNA was adopted to characterize the bacterial communities associated with adults and larvae reared on different diets, and estimate their composition and diversity. The core microbiota of this species was found to include some bacterial genera commonly associated with Lepidoptera. When a coverage-based integration of rarefaction and extrapolation of Hill numbers was used to compare groups of samples, the microbial diversity (estimated as phylogenetic diversity) differed among individuals reared on different diets, and also between larvae vs. adults. The lowest taxon diversity was found associated with individuals reared on M. chamomilla. Larvae fed with this fiber-rich diet had also a significantly slower development. The composition of the microbial community varied among individuals with different diets, but not between adults vs. larvae. This study highlights the important role of diet in shaping I. inquinata microbiota, but also suggests that the microbiota of non-feeding adult moths could be partially inherited from larvae

Mechanisms for electron transport in atomic-scale one-dimensional wires: soliton and polaron effects

We study one-electron tunneling through atomic-scale one-dimensional wires in the presence of coherent electron-phonon (e-ph) coupling. We use a full quantum model for the e-ph interaction within the wire with open boundary conditions. We illustrate the mechanisms of transport in the context of molecular wires subject to boundary conditions imposing the presence of a soliton defect in the molecule. Competition between polarons and solitons in the coherent transport is examined. The transport mechanisms proposed are generally applicable to other one-dimensional nanoscale systems with strong e-ph coupling.Comment: 7 pages, 4 figures, accepted for publication in Europhys. Let

Theory of Vibrationally Inelastic Electron Transport through Molecular Bridges

Vibrationally inelastic electron transport through a molecular bridge that is connected to two leads is investigated. The study is based on a generic model of vibrational excitation in resonant transmission of electrons through a molecular junction. Employing methods from electron-molecule scattering theory, the transmittance through the molecular bridge can be evaluated numerically exactly. The current through the junction is obtained approximately using a Landauer-type formula. Considering different parameter regimes, which include both the case of a molecular bridge that is weakly coupled to the leads, resulting in narrow resonance structures, and the opposite case of a broad resonance caused by strong interaction with the leads, we investigate the characteristic effects of coherent and dissipative vibrational motion on the electron transport. Furthermore, the validity of widely used approximations such as the wide-band approximation and the restriction to elastic transport mechanisms is investigated in some detail.Comment: Submited to PRB, revised version according to comments of referees (minor text changes and new citations

Electron transport in nanotube--molecular wire hybrids

We study contact effects on electron transport across a molecular wire sandwiched between two semi-infinite (carbon) nanotube leads as a model for nanoelectrodes. Employing the Landauer scattering matrix approach we find that the conductance is very sensitive to parameters such as the coupling strength and geometry of the contact. The conductance exhibits markedly different behavior in the two limiting scenarios of single contact and multiple contacts between the molecular wire and the nanotube interfacial atoms. In contrast to a single contact the multiple-contact configuration acts as a filter selecting single transport channels. It exhibits a scaling law for the conductance as a function of coupling strength and tube diameter. We also observe an unusual narrow-to-broad-to-narrow behavior of conductance resonances upon decreasing the coupling.Comment: 4 pages, figures include

Quantum inelastic conductance through molecular wires

We calculate non-perturbatively the inelastic effects on the conductance through a conjugated molecular wire-metal heterojunction, including realistic electron-phonon coupling. We show that at sub-band-gap energies the current is dominated by quantum coherent transport of virtual polarons through the molecule. In this regime, the tunneling current is strongly increased relative to the case of elastic scattering. It is essential to describe the full quantum coherence of the polaron formation and transport in order to obtain correct physics. Our results are generally applicable to one-dimensional atomic or molecular wires.Comment: 4 pages, 4 figures, accepted for publication in Physical Review Letter

Coherent electron-phonon coupling and polaron-like transport in molecular wires

We present a technique to calculate the transport properties through one-dimensional models of molecular wires. The calculations include inelastic electron scattering due to electron-lattice interaction. The coupling between the electron and the lattice is crucial to determine the transport properties in one-dimensional systems subject to Peierls transition since it drives the transition itself. The electron-phonon coupling is treated as a quantum coherent process, in the sense that no random dephasing due to electron-phonon interactions is introduced in the scattering wave functions. We show that charge carrier injection, even in the tunneling regime, induces lattice distortions localized around the tunneling electron. The transport in the molecular wire is due to polaron-like propagation. We show typical examples of the lattice distortions induced by charge injection into the wire. In the tunneling regime, the electron transmission is strongly enhanced in comparison with the case of elastic scattering through the undistorted molecular wire. We also show that although lattice fluctuations modify the electron transmission through the wire, the modifications are qualitatively different from those obtained by the quantum electron-phonon inelastic scattering technique. Our results should hold in principle for other one-dimensional atomic-scale wires subject to Peierls transitions.Comment: 21 pages, 8 figures, accepted for publication in Phys. Rev. B (to appear march 2001

A soil fungus confers plant resistance against a phytophagous insect by disrupting the symbiotic role of its gut microbiota

Plants generate energy flows through natural food webs, driven by competition for resources among organisms, which are part of a complex network of multitrophic interactions. Here, we demonstrate that the interaction between tomato plants and a phytophagous insect is driven by a hidden interplay between their respective microbiotas. Tomato plants colonized by the soil fungus Trichoderma afroharzianum, a beneficial microorganism widely used in agriculture as a biocontrol agent, negatively affects the development and survival of the lepidopteran pest Spodoptera littoralis by altering the larval gut microbiota and its nutritional support to the host. Indeed, experiments aimed to restore the functional microbial community in the gut allow a complete rescue. Our results shed light on a novel role played by a soil microorganism in the modulation of plant-insect interaction, setting the stage for a more comprehensive analysis of the impact that biocontrol agents may have on ecological sustainability of agricultural systems