Prescreening of biological and biorational fungicides against common hemp pathogens using in vitro analyses

Upon reintroduction of hemp in 2014 and legalization in 2018, labeled pesticides have remained limited. Further, consumer demand has aimed the market toward organic or chemical-free production systems. In efforts to manage diseases and pests in fields and greenhouses, producers turn toward biological and biorational formulations. Efficacy of these fungicides against common aerial diseases of hemp is largely unpublished. Challenges of efficacy testing, however, further delay or discourage research. In this study, we evaluated screening methods against some common biological products. The aim was to test a screening model in order to examine products against fungal pathogens and to identify demonstrable differences under controlled conditions. Thus, in this study, we prescreen 11 biological and biorational fungicides against four common fungal leaf and flower pathogens using three bioassays. Confirmation that the major modes of action for these products have measurable activity against major pathogens of hemp serves as a first step toward more complex field studies.

Recovery and Characterization of Orbital Angular Momentum Modes with Ghost Diffraction Holography

Orbital angular momentum (OAM) of optical vortex beams has been regarded as an independent physical dimension of light with predominant information-carrying potential. However, the presence of scattering environment and turbulent atmosphere scrambles the helical wavefront and destroys the orthogonality of modes in vortex beam propagation. Here, we propose and experimentally demonstrate a new basis for the recovery of the OAM mode using a holographic ghost diffraction scheme. The technique utilizes the speckle field generated from a rotating diffuser for optical vortex mode encoding, and the fourth-order correlation of the speckle field for the efficient recovery of the associated modes. Furthermore, we successfully demonstrate the complex-field recovery of OAM modes by the adoption of a holography scheme in combination with the ghost diffraction system. We evaluate the feasibility of the approach by simulation and followed by experimental demonstration for the recovery of various sequentially encoded OAM modes. Finally, the efficacy of the recovered modes was quantitatively analyzed by an OAM mode analysis utilizing orthogonal projection scheme.

Diversity of mistletoes and their distribution in Dramaga Campus, West Java, Indonesia

Mistletoes are flowering plants in the Santalales order that parasitize the branches of trees and shrubs. The objective of this research was to reveal the diversity of mistletoe species and record their distribution within this study site. The study site was Dramaga Campus (240 ha), which consisted of a mosaic of tree plantation, experimental fields, buildings, and a housing complex. Field research was conducted in February-March 2021 by censusing all mistletoes, their distribution, and plant species parasitized by the mistletoes. There were 351 individual mistletoes found, consisted of 5 species: Dendrophthtoepentandra (55.2%), Viscum ovalifolium (32.3%), Scurrula atropurpurea (9.1%), Macrosolen chochinchinensis (2.8%), and Viscum articulatum (0.6%). These mistletoes were found mostly on branches or twigs (99.1%) and few on trunks (0.9%) of 49 tree species (25 families) having an average height of 14.9±4.2m, and diameter 34.11± 22.22cm. Tree species frequently parasitized were Falcataria moluccana (32.8%), followed by Samanea saman (12.5%), and Averrhoa carambola (7.7%). Most mistletoes were found in the open area (99.1%), including on trees between/among buildings and along roads/streets, mainly on the south and southeast part of the campus. The mistletoe attacked in this research location was included in the low category (79.4%).

Measuring migration 2.0: a review of digital data sources

The interest in human migration is at its all-time high, yet data to measure migration is notoriously limited. “Big data” or “digital trace data” have emerged as new sources of migration measurement complementing ‘traditional’ census, administrative and survey data. This paper reviews the strengths and weaknesses of eight novel, digital data sources along five domains: reliability, validity, scope, access and ethics. The review highlights the opportunities for migration scholars but also stresses the ethical and empirical challenges. This review intends to be of service to researchers and policy analysts alike and help them navigate this new and increasingly complex field.

Gravitational waves and dark photon dark matter from axion rotations

An axion rotating in field space can produce dark photons in the early universe via tachyonic instability. This explosive particle production creates a background of stochastic gravitational waves that may be visible at pulsar timing arrays or other gravitational wave detectors. This scenario provides a novel history for dark photon dark matter. The dark photons may be warm at a level detectable in future 21-cm line surveys. For a consistent cosmology, the radial direction of the complex field containing the axion must be thermalized. We explore a concrete thermalization mechanism in detail and also demonstrate how this setup can be responsible for the generation of the observed baryon asymmetry.

Wind turbine main-bearing lubrication – Part 1: An introductory review of elastohydrodynamic lubrication theory

This paper is the first in a two-part study on lubrication in wind turbine main-bearings. Elastohydrodynamic lubrication is a complex field, the formulas and results from which should not be applied blindly, but with proper awareness and consideration of their context, validity and limitations in any given case. The current paper, “Part 1”, therefore presents an introductory review of elastohydrodynamic lubrication theory in order to provide this necessary background and context in an accessible form, promoting cross-disciplinary understanding. Fundamental concepts, derivations and formulas are presented, followed by the more advanced topics of: starvation, dynamic effects, surface roughness interactions and grease lubrication. “Part 2” applies the presented material in order to analyse wind turbine main-bearing lubrication in the context of available film thickness formulas and related results from lubrication theory. Aside from the main-bearing, the material presented here is also applicable to other lubricated non-conformal contacts in wind turbines, including pitch and yaw bearings and gear-teeth.

An 𝔽 p2 -maximal Wiman sextic and its automorphisms

In 1895 Wiman introduced the Riemann surface 𝒲 of genus 6 over the complex field ℂ defined by the equation X 6+Y 6+ℨ 6+(X 2+Y 2+ℨ 2)(X 4+Y 4+ℨ 4)−12X 2 Y 2 ℨ 2 = 0, and showed that its full automorphism group is isomorphic to the symmetric group S 5. We show that this holds also over every algebraically closed field 𝕂 of characteristic p ≥ 7. For p = 2, 3 the above polynomial is reducible over 𝕂, and for p = 5 the curve 𝒲 is rational and Aut(𝒲) ≅ PGL(2,𝕂). We also show that Wiman’s 𝔽192 -maximal sextic 𝒲 is not Galois covered by the Hermitian curve H19 over the finite field 𝔽192 .