554 research outputs found
Evaluation of biofungicides for control of clubroot on canola
Non-Peer ReviewedClubroot of canola, caused by the protist pathogen Plasmodiophora brassicae (Pb), is an
emerging threat to canola production in western Canada. Effective/practical control options
are currently lacking. This study was initiated to assess registered microbial fungicides for
control of clubroot on canola. Selected biofungicides were initially applied as a soil drench
and the fungicides Allegro and Ranman were also included for comparisons. Selected
products were further evaluated at varying concentrations, soil drench volumes, and for seed
treatment. At moderate disease pressure, the biofungicides Serenade and Prestop, as well as
synthetic fungicides Allegro and Ranman were highly effective as a soil-drench treatment,
reducing clubroot severity by 85–100% in controlled conditions. Biofungicide concentration
appeared to be important while soil-drench volumes may be reduced. All products, however,
were significantly less effective or ineffective under extremely high disease pressure. All
products were less efficacious in trials using infested field soils, a circumstance that may be
related to treatment timing. Results from seed-treatment trials were too variable to draw a
conclusion but there was a strong indication that this approach be successful though more
research is required on microbial formulations. Serenade, Prestop, Allegro, and Ranman
should be further evaluated under field conditions for clubroot control
Optimisation and validation of a PCR to detect viable Tenacibaculum maritimum in salmon skin tissue samples
A PCR protocol was optimised and validated for the detection of viable Tenacibaculum maritimum cells in salmon skin tissue. Viability conventional (vPCR) and quantitative PCR (v-qPCR) assays both had a limit of detection of 103 CFU mL−1 viable cells. The v-qPCR assay showed a linear quantification over 4 log units. Conventional vPCR showed complete signal suppression when only dead cells were present at concentrations lower than 106 CFU mL−1. While the v-qPCR did not result in complete suppression when only dead cells were present, a method was developed to determine if viable cells were present based on the % Δ in cycle threshold (Ct) value. The procedure was validated for high-throughput processing and an enrichment protocol was validated to reliably detect low concentrations of viable cells both with and without a high background of dead cells. Performing this protocol on naturally infected tissues showed that vPCR and v-qPCR reduced the potential for false positives compared to using conventional PCR and qPCR. The optimised protocol developed for this study provides an efficient, reliable and robust alternative for the detection of viable T. maritimum in skin tissue
Study of Neutron-Induced Ionization in Helium and Argon Chamber Gases
Ion chambers used to monitor the secondary hadron and tertiary muon beam in
the NuMI neutrino beamline will be exposed to background particles, including
low energy neutrons produced in the beam dump. To understand these backgrounds,
we have studied Helium- and Argon-filled ionization chambers exposed to intense
neutron fluxes from PuBe neutron sources ( MeV). The sources emit
about 10 neutrons per second. The number of ion pairs in the chamber gas
volume per incident neutron is derived. While limited in precision because of a
large gamma ray background from the PuBe sources, our results are consistent
with the expectation that the neutrons interact purely elastically in the
chamber gas.Comment: accepted for publication in NIM
Big Bang Nucleosynthesis with Gaussian Inhomogeneous Neutrino Degeneracy
We consider the effect of inhomogeneous neutrino degeneracy on Big Bang
nucleosynthesis for the case where the distribution of neutrino chemical
potentials is given by a Gaussian. The chemical potential fluctuations are
taken to be isocurvature, so that only inhomogeneities in the electron chemical
potential are relevant. Then the final element abundances are a function only
of the baryon-photon ratio , the effective number of additional neutrinos
, the mean electron neutrino degeneracy parameter , and
the rms fluctuation of the degeneracy parameter, . We find that for
fixed , , and , the abundances of helium-4,
deuterium, and lithium-7 are, in general, increasing functions of .
Hence, the effect of adding a Gaussian distribution for the electron neutrino
degeneracy parameter is to decrease the allowed range for . We show that
this result can be generalized to a wide variety of distributions for .Comment: 9 pages, 3 figures, added discussion of neutrino oscillations,
altered presentation of figure
Use of cultivar resistance and crop rotation with Bacillus subtilis for clubroot control in canola
Non-Peer ReviewedThis study was conducted to assess additional strategies potentially complimentary to cultivar
resistance or biocontrol in control of clubroot. New granular Bacillus subtilis formulations
and a seed dressing method were developed to facilitate biofungicide delivery in field trials.
The granular formulations were applied in furrow during seeding at 50 kg/ha to a clubroot
resistant (CR) and susceptible (CS) canola cultivar, respectively, in three field trials. The seed
dressing applied approximately 1×105 to 5×106 cfu/seed doses of the biocontrol agent, and
was evaluated on the CS cultivar seeded to different crop-rotation scenarios where the plots
had a 1-year, 3-year, or 11-year break from last canola crop. Clubroot disease pressure was
high at all trial sites with disease severity indexes (DSI) ranging from 69% to 98% on the CS
cultivar. None of the granular formulations reduced clubroot substantially, whereas the CR
cultivar showed a high effect, reducing DSI to below 15% and doubling the yield over that of
CS cultivar. Plots of varying rotation showed a pattern of clubroot pathogen pressure, with
those of 1-year break from canola being the highest. The DSI for all rotational scenarios was
high, reaching 100% in short-rotation plots. Biofungicide seed dressing did not reduce DSI,
but longer crop rotation often reduced gall size slightly, showed much milder above-ground
damage, and increased the yield significantly relative to short rotation in two separate trials.
Even a 3-year break from canola was highly beneficial, with the yield doubled as opposed to
that with only 1-year break from canola
Biological anthropology in the Indo-Pacific Region: New approaches to age-old questions
Biological anthropological research, the study of both modern and past humans, is a burgeoning field in the Indo-Pacific region. It is becoming increasingly apparent that the unique environments of the Indo-Pacific have resulted in an archaeological record that does not necessarily align with those in the northern hemisphere. New, regionally-specific archaeological models are being developed, and biological anthropological research has an important role to play in establishing past human experience within these models. In the Indo-Pacific, research using ancient and modern human tissues is adding insight into global processes of prehistoric settlement and migrations, subsistence change and human biosocial adaptation. This review synthesises current themes in biological anthropology in this region. It highlights the diverse methods and approaches used by biological anthropologists to address globally-relevant archaeological questions. In recent decades a collaborative approach between archaeologists, biological anthropologists and local communities has become the norm in the region. The many positive outcomes of this multi-disciplinary approach are highlighted here through the use of regionally-specific case studies. This review ultimately aims to stimulate further collaborations between archaeologists, biological anthropologists and the communities in the region, and demonstrate how the evidence from Indo-Pacific research may be relevant to global archaeological models
Large Second Harmonic Kerr rotation in GaFeO3 thin films on YSZ buffered Silicon
Epitaxial thin films of gallium iron oxide (GaFeO3) are grown on (001)
silicon by pulsed laser deposition (PLD) using yttrium-stabilized zirconia
(YSZ) buffer layer. The crystalline template buffer layer is in-situ PLD grown
through the step of high temperature stripping of the intrinsic silicon surface
oxide. The X-ray diffraction pattern shows c-axis orientation of YSZ and b-axis
orientation of GaFeO3 on Si (100) substrate. The ferromagnetic transition
temperature (TC ~ 215 K) is in good agreement with the bulk data. The films
show a large nonlinear second harmonic Kerr rotation of ~15 degrees in the
ferromagnetic state.Comment: 16 pages, 4 figures, To be published in J. Magn. Magn. Ma
Childhood Adversity Moderates Change in Latent Patterns of Psychological Adjustment during the COVID-19 Pandemic: Results of a Survey of U.S. Adults
Emerging evidence suggests that the consequences of childhood adversity impact later psychopathology by increasing individuals’ risk of experiencing difficulties in adjusting to stressful situations later in life. The goals of this study were to: (a) identify sociodemographic factors associated with subgroups of psychological adjustment prior to and after the onset of the COVID-19 pandemic and (b) examine whether and to what extent types of childhood adversity predict transition probabilities. Participants were recruited via multiple social media platforms and listservs. Data were collected via an internet-based survey. Our analyses reflect 1942 adults (M = 39.68 years); 39.8% reported experiencing at least one form of childhood adversity. Latent profile analyses (LPAs) and latent transition analyses (LTAs) were conducted to determine patterns of psychological adjustment and the effects of childhood adversity on transition probabilities over time. We identified five subgroups of psychological adjustment characterized by symptom severity level. Participants who were younger in age and those who endorsed marginalized identities exhibited poorer psychological adjustment during the pandemic. Childhood exposure to family and community violence and having basic needs met as a child (e.g., food, shelter) significantly moderated the relation between latent profile membership over time. Clinical and research implications are discussed
Restoring shellfish reefs: Global guidelines for practitioners and scientists
Widespread global declines in shellfish reefs (ecosystem-forming bivalves such as oysters and mussels) have led to growing interest in their restoration and protection. With restoration projects now occurring on four continents and in at least seven countries, global restoration guidelines for these ecosystems have been developed based on experience over the past two decades. The following key elements of the guidelines are outlined: (a) the case for shellfish reef resto- ration and securing financial resources; (b) planning, feasibility, and goal set- ting; (c) biosecurity and permitting; (d) restoration in practice; (e) scaling up from pilot to larger scale restoration, (f) monitoring, (g) restoration beyond oyster reefs (specifically mussels), and (h) successful communication for shell- fish reef restoration projects
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