A potential microbial control for fireweed (Epilobium angustifolium)

Des plants infectés d'épi lobe à feuilles étroites (Epilobium angustifolium) ont été récoltés au Québec et les organismes isolés de ces plants ont été évalués comme agents potentiels de lutte biologique. Treize champignons pathogènes ont été isolés et trois d'entre eux (Colletotrichum dematium, Seimatosporium kriegerianum et Alternaria alternata) ont été virulents lors d'essais préliminaires de sélection. Le plus virulent de ceux-ci, C. dematium, a causé d'importantes lésions sur les feuilles et les tiges des plantes infectées et a été sélectionné pour une étude plus approfondie. La production d'inoculum a été optimale sur gélose à base d'extrait de malt modifié, et la virulence a été augmentée par l'enlèvement de la matrice des conidies à l'aide d'acide tannique et par l'addition d'extraits d'Aloe saponaria. La champignon a été pathogène pour l'épilobe à feuilles étroites et l'E. lanceolatum, alors que les autres espèces évaluées ont été résistantes ou immunisées. Les dimensions des conidies et des appressoria et le nombre restreint de plantes-hôtes supportent l'hypothèse que cet isolât pourrait être une forme-espèce non répertoriée. L'application d'une formulation de conidies âgées de 10 à 15 j, à une concentration de 109 conidies m-2 et après une période de rosée de 18 à 24 h, a causé la mortalité de 100% des rosettes d'épilobe à feuilles étroites âgées de 7 semaines dans les 48 h suivant l'application. La virulence a été réduite chez les plantes plus âgées. Dans l'essai au champ, la croissance des rosettes infectées a diminué de 33%. Ces résultats démontrent le potentiel de C. dematium comme agent de lutte biologique en sylviculture contre les plantules d'épilobe à feuilles étroites.Diseased fireweed (Epilobium angustifolium) plants were collected in Quebec and organisms isolated from these plants were evaluated as potential biocontrol agents. Thirteen pathogenic fungi were isolated and three of these (Colletotrichum dematium, Seimatosporium kriegerianum, and Alternaria alternata) were virulent in initial screening assays. C. dematium was selected for further study because it was the most virulent pathogen, causing large necrotic lesions on leaves and stems of infected plants. Inoculum production was optimized on modified malt extract agar and the virulence enhanced by suppression of the conidial matrix with tannic acid and the addition of extracts of Aloe saponaria. The fungus was pathogenic to fireweed and E. lanceolatum, while other test species were very resistant or immune. Measurements of conidial and appressorial dimensions and its restricted host range support the hypothesis that the isolate may be an unreported form-species. Application of formulated conidia consistently provided 100% mortality of 7-wk-old inoculated fireweed rosettes within 48 h using 109 conidia m-2, from 10- to 15-d-old inoculum, and a 18- to 24-h dew period. Virulence was diminished in older plants. In field trials, growth of inoculated rosettes was reduced by 33%. These results suggest that C. dematium is a promising candidate for further development as a control agent for seedling fireweed in silviculture

The feasibility of a randomised controlled trial of Dyadic Developmental Psychotherapy

Background: Maltreated children have significant and complex problems which clinicians find difficult to diagnose and treat. Previous US pilot work suggests that Dyadic Developmental Psychotherapy (DDP) may be effective; however, rigorous evidence from a randomised controlled trial (RCT) is lacking. The purpose of this study is to establish the feasibility of an RCT of DDP by exploring the ways that DDP is operating across different UK sites and the impacts of current practice on the potential set-up of an RCT. Methods: Qualitative methods (interviews, focus groups and teleconferences) were used to explore trial feasibility with therapists and service managers from teams implementing both DDP and possible control interventions. Data were analysed thematically and related to various aspects of trial design. Results: DDP was commonly regarded as having a particular congruence with the complexity of maltreatment-associated problems and a common operating model of DDP was evident across sites. A single control therapy was harder to establish, however, and it is likely to be a non-specific and context-dependent intervention/s offered within mainstream Child and Adolescent Mental Health Services (CAMHS). Because a ‘gold standard’ Treatment as Usual (TAU) does not currently exist, randomisation between DDP and TAU (CAMHS) therefore looks feasible and ethical. The nature of family change during DDP was regarded as multi-faceted, non-linear and relationship-based. Assessment tools need to be carefully considered in terms of their ability to capture change that covers both individual child and family-based functioning. Conclusions: An RCT of DDP is feasible and timely. This study has demonstrated widespread interest, support and engagement regarding an RCT and permissions have been gained from sites that have shown readiness to participate. As maltreated children are among the most vulnerable in society, and as there are currently no treatments with RCT evidence, such a trial would be a major advance in the field

Constraints on composite Dirac neutrinos from observations of galaxy clusters

Recently, to explain the origin of neutrino masses a model based on confining some hidden fermionic bound states into right-handed chiral neutrinos has been proposed. One of the consequences of condensing the hidden sector fields in this model is the presence of sterile composite Dirac neutrinos of keV mass, which can form viable warm dark matter particles. We have analyzed constraints on this model from the observations of satellite based telescopes to detect the sterile neutrinos in clusters of galaxies.Comment: 17 pages, 2 figures, minor modifications, a reference is added, this manuscript is published in Physics Letters

Cosmological parameter estimation using Very Small Array data out to ℓ= 1500

We estimate cosmological parameters using data obtained by the Very Small Array (VSA) in its extended configuration, in conjunction with a variety of other cosmic microwave background (CMB) data and external priors. Within the flat Λ cold dark matter (ΛCDM) model, we find that the inclusion of high-resolution data from the VSA modifies the limits on the cosmological parameters as compared to those suggested by the Wilkinson Microwave Anisotropy Probe (WMAP) alone, while still remaining compatible with their estimates. We find that Ωbh2= 0.0234+0.0012−0.0014, Ωdmh2= 0.111+0.014−0.016, h= 0.73+0.09−0.05, nS= 0.97+0.06−0.03, 1010AS= 23+7−3 and τ= 0.14+0.14−0.07 for WMAP and VSA when no external prior is included. On extending the model to include a running spectral index of density fluctuations, we find that the inclusion of VSA data leads to a negative running at a level of more than 95 per cent confidence ( nrun=−0.069 ± 0.032 ), something that is not significantly changed by the inclusion of a stringent prior on the Hubble constant. Inclusion of prior information from the 2dF galaxy redshift survey reduces the significance of the result by constraining the value of Ωm. We discuss the veracity of this result in the context of various systematic effects and also a broken spectral index model. We also constrain the fraction of neutrinos and find that fν < 0.087 at 95 per cent confidence, which corresponds to mν < 0.32 eV when all neutrino masses are equal. Finally, we consider the global best fit within a general cosmological model with 12 parameters and find consistency with other analyses available in the literature. The evidence for nrun < 0 is only marginal within this model

Influences of Non-fullerene Acceptor Fluorination on Three-Dimensional Morphology and Photovoltaic Properties of Organic Solar Cells

Fluorination of conjugated molecules has been established as an effective structural modification strategy to influence properties and has attracted extensive attention in organic solar cells (OSCs). Here, we have investigated optoelectronic and photovoltaic property changes of OSCs made of polymer donors with the non-fullerene acceptors (NFAs) ITIC and IEICO and their fluorinated counterparts IT-4F and IEICO-4F. Device studies show that fluorinated NFAs lead to reduced Voc but increased Jsc and fill-factor (FF), and therefore, the ultimate influence to efficiency depends on the compensation of Voc loss and gains of Jsc and FF. Fluorination lowers energy levels of NFAs, reduces their electronic band gaps, and red-shifts the absorption spectra. The impact of fluorination on the molecular order depends on the specific NFA, and the conversion of ITIC to IT-4F reduces the structural order, which can be reversed after blending with the donor PBDB-T. Contrastingly, IEICO-4F presents stronger π–π stacking after fluorination from IEICO, and this is further strengthened after blending with the donor PTB7-Th. The photovoltaic blends universally present a donor-rich surface region which can promote charge transport and collection toward the anode in inverted OSCs. The fluorination of NFAs, however, reduces the fraction of donors in this donor-rich region, consequently encouraging the intermixing of donor/acceptor for efficient charge generation

Correlating three-dimensional morphology with function in PBDB-T:IT-M non-fullerene organic solar cells

In this work, the correlation between three‐dimensional morphology and device performance of PBDB‐T:IT‐M non‐fullerene organic solar cells is investigated. We found that a PBDB‐T‐rich top layer formed when the PBDB‐T:IT‐M film is cast on PEDOT:PSS, indicating a vertical component distribution that will hinder electron transport toward the cathode in a conventional device. This PBDB‐T‐rich top layer remained upon low‐temperature annealing at 80 °C, but disappeared when the annealing temperature is raised, resulting in an optimum annealing temperature of 160 °C for conventional devices as the removal of this polymer‐rich layer facilitates electron transport toward the top cathode layer. The PBDB‐T‐rich layer is also found in the surface region of the PBDB‐T:IT‐M film cast on a TiO2 substrate, but in this case it remained after thermal annealing at 80 or 160 °C, leading to a favorable vertical stratification for efficient charge collection in inverted devices. Although thermal annealing can enhance the crystallinity of PBDB‐T:IT‐M blend and lead to improved charge mobility, the correlation length of the PBDB‐T component increased excessively under annealing at 160 °C. Further, the packing of IT‐M clusters became loose upon high temperature annealing, an effect we believe results in more diffuse interfaces with PBDB‐T that result in reduced charge separation efficiency, consequently reducing the short‐circuit current in the inverted devices

Constraints on the Ultra High Energy Photon flux using inclined showers from the Haverah Park array

We describe a method to analyse inclined air showers produced by ultra high energy cosmic rays using an analytical description of the muon densities. We report the results obtained using data from inclined events (60^{\circ}<\theta<80^{\circ}) recorded by the Haverah Park shower detector for energies above 10^19 eV. Using mass independent knowledge of the UHECR spectrum obtained from vertical air shower measurements and comparing the expected horizontal shower rate to the reported measurements we show that above 10^19 eV less than 48 % of the primary cosmic rays can be photons at the 95 % confidence level and above 4 X 10^19 eV less than 50 % of the cosmic rays can be photonic at the same confidence level. These limits place important constraints on some models of the origin of ultra high-energy cosmic rays.Comment: 45 pages, 25 figure

Collinear helium under periodic driving: stabilization of the asymmetric stretch orbit

The collinear eZe configuration of helium, with the electrons on opposite sides of the nucleus, is studied in the presence of an external electromagnetic (laser or microwave) field. We show that the classically unstable "asymmetric stretch" orbit, on which doubly excited intrashell states of helium with maximum interelectronic angle are anchored, can be stabilized by means of a resonant driving where the frequency of the electromagnetic field equals the frequency of Kepler-like oscillations along the orbit. A static magnetic field, oriented parallel to the oscillating electric field of the driving, can be used to enforce the stability of the configuration with respect to deviations from collinearity. Quantum Floquet calculations within a collinear model of the driven two-electron atom reveal the existence of nondispersive wave packets localized on the stabilized asymmetric stretch orbit, for double excitations corresponding to principal quantum numbers of the order of N > 10.Comment: 13 pages, 12 figure

Academic freedom: in justification of a universal ideal

This paper examines the justification for, and benefits of, academic freedom to academics, students, universities and the world at large. The paper surveys the development of the concept of academic freedom within Europe, more especially the impact of the reforms at the University of Berlin instigated by Wilhelm von Humboldt. Following from this, the paper examines the reasons why the various facets of academic freedom are important and why the principle should continue to be supported

An analysis of the quality of experimental design and reliability of results in tribology research

In recent years several high profile projects have questioned the repeatability and validity of scientific research in the fields of psychology and medicine. In general, these studies have shown or estimated that less than 50% of published research findings are true or replicable even when no breaches of ethics are made. This high percentage stems from widespread poor study design; either through the use of underpowered studies or designs that allow the introduction of bias into the results. In this work, we have aimed to assess, for the first time, the prevalence of good study design in the field of tribology. A set of simple criteria for factors such as randomisation, blinding, use of control and repeated tests has been made. These criteria have been used in a mass review of the output of five highly regarded tribology journals for the year 2017. In total 379 papers were reviewed by 26 reviewers, 28% of the total output of the journals selected for 2017. Our results show that the prevalence of these simple aspects of study design is poor. Out of 290 experimental studies, 2.2% used any form of blinding, 3.2% used randomisation of either the tests or the test samples, while none randomised both. 30% repeated experiments 3 or more times and 86% of those who repeated tests used single batches of test materials. 4.4% completed statistical tests on their data. Due to the low prevalence of repeated tests and statistical analysis it is impossible to give a realistic indication of the percentage of the published works that are likely to be false positives, however these results compare poorly to other more well studied fields. Finally, recommendations for improved study design for researchers and group design for research group leaders are given