Screening Eucalyptus cloeziana and E. argophloia populations for resistance to Puccinia psidii

Disease screening to determine the threat Puccinia psidii poses to plantation and native eucalypts in Australia was undertaken in half-sib families of two contrasting eucalypt species, Eucalyptus cloeziana and E. argophloia. Artificial inoculation with a single-lesion isolate of P. psidii was used to screen these species for resistance to the biotype of P. psidii established in Australia. The objective was to characterize resistance to P. psidii within these two distinct species: E. argophloia, a vulnerable species with a narrow distribution, and E. cloeziana, a species with a broad and extensive distribution in Queensland. Results for E. cloeziana indicate that inland provenances are more resistant to P. psidii infection than provenances from coastal regions. Heritability estimates for the two assessment systems used (resistance on a 1-to-5 ordinal scale verses resistance on a 0-to-1 binomial scale) were low to high (0.24 to 0.63) for E. argophloia and moderate to high (0.4 to 0.91) for E. cloeziana, indicating a significant level of additive genetic variance for rust resistance within the populations. This study demonstrates the potential to select resistant families within the tested populations and indicates that P. psidii could detrimentally affect these species in native forests, nurseries, and plantations. Disease screening to determine the threat Puccinia psidii poses to plantation and native eucalypts in Australia was undertaken in half-sib families of two contrasting eucalypt species, Eucalyptus cloeziana and E. argophloia. Artificial inoculation with a single-lesion isolate of P. psidii was used to screen these species for resistance to the biotype of P. psidii established in Australia. The objective was to characterize resistance to P. psidii within these two distinct species: E. argophloia, a vulnerable species with a narrow distribution, and E. cloeziana, a species with a broad and extensive distribution in Queensland. Results for E. cloeziana indicate that inland provenances are more resistant to P. psidii infection than provenances from coastal regions. Heritability estimates for the two assessment systems used (resistance on a 1-to-5 ordinal scale verses resistance on a 0-to-1 binomial scale) were low to high (0.24 to 0.63) for E. argophloia and moderate to high (0.4 to 0.91) for E. cloeziana, indicating a significant level of additive genetic variance for rust resistance within the populations. This study demonstrates the potential to select resistant families within the tested populations and indicates that P. psidii could detrimentally affect these species in native forests, nurseries, and plantations

Timing of Early-Life Stress and the Development of Brain-Related Capacities

This work is licensed under a Creative Commons Attribution 4.0 International License.Early-life stress (ELS) poses risks for developmental and mental health problems throughout the lifespan. More research is needed regarding how specific ELS experiences influence specific aspects of neurodevelopment. We examined the association between ELS, defined as severe adversity (e.g., domestic violence, caregiver drug use) and severe relational poverty (e.g., caregiver neglect, lack of caregiver attunement), occurring during the first 2 months of life and a variety of brain-related, clinician-rated functions, including self-regulation and relational capacities. Interdisciplinary clinicians using the Neurosequential Model of Therapeutics (NMT), an approach to clinical problem solving, reported on the timing and type of treatment-seeking children’s (N = 2,155; 8–10 years) stressful experiences during four developmental periods: Perinatal (0–2 months), Infancy (2–12 months), Early Childhood (13 months to 4 years), and Childhood (4–11 years). They also reported on children’s current functioning in 32 brain-related domains (e.g., sleep, arousal, impulsivity, empathy, concrete cognition). Non-negative matrix factorization (NMF) was conducted on the 32 brain-related domains to identify latent factors, yielding four factors comprising Sensory Integration, Self-Regulation, Relational, and Cognitive functioning. Regularized hierarchical models were then used to identify associations between ELS and each latent factor while controlling for stress occurring during subsequent developmental periods, and children’s current degree of relational health. ELS (stress occurring during the first 2 months of life), specifically a severe lack of positive relational experiences (e.g., caregiver neglect, lack of caregiver attunement), was associated with the Sensory Integration and Self-Regulation factors. The Relational factor was better explained by stress occurring during childhood, and the Cognitive factor by stress occurring during infancy and childhood. Implications for how the timing and type of stress experiences may influence brain-related outcomes that are observed in clinical settings are discussed. Future directions include longitudinal follow-ups and greater specification of environmental variables, such as types of interventions received and when they were received, that may interact with ELS experiences to influence brain-related outcomes

Screening Eucalyptus cloeziana and E. argophloia populations for resistance to Puccinia psidii

Disease screening to determine the threat Puccinia psidii poses to plantation and native eucalypts in Australia was undertaken in half-sib families of two contrasting eucalypt species, Eucalyptus cloeziana and E. argophloia. Artificial inoculation with a single-lesion isolate of P. psidii was used to screen these species for resistance to the biotype of P. psidii established in Australia. The objective was to characterize resistance to P. psidii within these two distinct species: E. argophloia, a vulnerable species with a narrow distribution, and E. cloeziana, a species with a broad and extensive distribution in Queensland. Results for E. cloeziana indicate that inland provenances are more resistant to P. psidii infection than provenances from coastal regions. Heritability estimates for the two assessment systems used (resistance on a 1-to-5 ordinal scale verses resistance on a 0-to-1 binomial scale) were low to high (0.24 to 0.63) for E. argophloia and moderate to high (0.4 to 0.91) for E. cloeziana, indicating a significant level of additive genetic variance for rust resistance within the populations. This study demonstrates the potential to select resistant families within the tested populations and indicates that P. psidii could detrimentally affect these species in native forests, nurseries, and plantations. Disease screening to determine the threat Puccinia psidii poses to plantation and native eucalypts in Australia was undertaken in half-sib families of two contrasting eucalypt species, Eucalyptus cloeziana and E. argophloia. Artificial inoculation with a single-lesion isolate of P. psidii was used to screen these species for resistance to the biotype of P. psidii established in Australia. The objective was to characterize resistance to P. psidii within these two distinct species: E. argophloia, a vulnerable species with a narrow distribution, and E. cloeziana, a species with a broad and extensive distribution in Queensland. Results for E. cloeziana indicate that inland provenances are more resistant to P. psidii infection than provenances from coastal regions. Heritability estimates for the two assessment systems used (resistance on a 1-to-5 ordinal scale verses resistance on a 0-to-1 binomial scale) were low to high (0.24 to 0.63) for E. argophloia and moderate to high (0.4 to 0.91) for E. cloeziana, indicating a significant level of additive genetic variance for rust resistance within the populations. This study demonstrates the potential to select resistant families within the tested populations and indicates that P. psidii could detrimentally affect these species in native forests, nurseries, and plantations

Selection of Corymbia citriodora for pulp productivity

Evaluation of a series of spotted gum (Corymbia citirodora) progeny trials, established in the subtropical region of Queensland, Australia, was undertaken to provide information for the development of advanced-generation breeding populations suitable for pulp production. Measurements of growth at two ages were combined with assessments of wood density and pulp yield from a selected sample of provenances to provide comparisons between provenances, to generate genetic parameter estimates and to predict genetic gain potential. Although growth at this age was moderate relative to other eucalypts, the near-infrared predictions of average wood density of 756 kg m-3 and pulp yield of 55% indicate the species has considerable potential as a pulpwood crop. A pulp productivity breeding objective was used to identify production populations using a range of selection trait weightings to determine potential genetic gain for pulp productivity. Genetic parameters indicated (1) levels of genetic control were moderate for all traits and higher for wood property traits, (2) genetic improvements could be achieved by selection among and within provenances with greater levels of improvement available from selection within populations, (3) genotype by environment interactions were negligible, (4) genetic correlations between traits were favourable, and (5) selection of volume production alone would maximise improvements in pulp productivity

Context and Scale Mediate the Impact of Climate on a Widespread Avian Predator

Anthropogenic climate change is threatening biodiversity as I currently understand it. There is now a large body of work highlighting species responses, globally, to this threat. Importantly, responses at the species level emerge from responses at lower levels of biological organization (individuals and populations) across a species’ geographic range. For widespread species in particular, perturbations due to climate warming or other environmental changes in one part of a species’ range may not have the same effect as in another part of that species’ range. In fact, different populations within a species may show opposing trends in response to the same environmental stressor. Species level responses also have consequences for higher levels of biological organization (communities and ecosystems), depending on the rate and duration of the response. Integrating across biological, spatial, and temporal scales is therefore critical to a deeper understanding of biotic responses to anthropogenic climate change. My dissertation takes an integrative, multi-scale approach to better understand the role climate has played in shaping the distribution and dynamics of an iconic falcon in North America, the American kestrel. This species, a widespread generalist that is common across North America, is experiencing one of the most dramatic declines among all North American raptor species. Determining the degree to which anthropogenic climate change has played a role in this decline, or not, is an urgent area of inquiry. My second chapter addresses gaps in knowledge by presenting an analysis of whether the interactive effects of climate, the structure and composition of the landscape, and primary productivity of the breeding grounds have impacted nest success in a population of American kestrels in the high desert region of Central Oregon over a 7-year period and examining how the spatial and temporal grain of the data impacts results. I find that primary productivity has greater explanatory power than either climate or landscape variables. However, seasonal variables (nest initiation date, nest age and day-of-year) emerge as the most important predictors of variation in nest success regardless of primary production. These models also suggest that longer-term annual averages of environmental variables may not be as informative with respect to nest success as variables that capture within-season variation in the environment. In addition, I find no evidence of advancing phenology as has been found in other populations in similar habitats and at similar latitudes as this population. Chapters 3 and 4 of my dissertation I turn to the relationship between body size and climate in the American kestrel. Evidence from bird species worldwide has shown reductions in mean body sizes over the past 50-100 years consistent with the notion of a response to climate warming. Body size has been shown to scale allometrically with many fundamental physiological, ecological, and evolutionary processes, raising concerns that asynchronous shifts in body size among species could lead to unexpected shifts in community and ecosystem dynamics. Yet previous studies of body size in birds vary with respect to how body size is measured. Measuring size is not a trivial matter, and the methods used can impact interpretation. In Chapter 3, I quantify size of kestrel sternums, a structural size element, via 3D geometric morphometrics to assess which standard non-structural (linear) morphological measurements that are typically applied to living birds or historical museum specimens (study skins) best capture the true structural size of a specimen. I find that single, commonly applied proxy measures of size in birds, such as mass, wing cord, or tarsus length, are poor representatives of structural size in the American kestrel, and that a combination of measurements from the wing, tail, leg and bill may be more appropriate for studies relating size to environmental parameters in this species. In Chapter 4, I then use a combination of measurements from a data set of museum study skins to evaluate the degree to which American kestrels across North and Central America conform to Bergmann’s Rule and Allen’s rule, common ecogeographic rules relating body size and appendage length, respectively, to latitude. I use a spatial regression framework to examine patterns in size and appendage length across 60° of latitude and over a 112-year period. I then integrate climate models with satellite-derived data on primary productivity and a dataset of competitor richness and body sizes compiled from the literature to test common hypotheses about the mechanisms underlying these patterns. I find no evidence for a change in the average body size of kestrels through time when examined at the continental scale, although, at smaller spatial scales, many regions do show significant trends in morphology through time. I do find support for Bergmann’s rule in American kestrels across the Northern hemisphere. In addition, the mechanism predicting size variation in American kestrels are found to be congruent across different spatial scales. I also find that bill size in American kestrels aligns with predictions from Allen’s rule. Taken as a whole, the studies presented in this dissertation add to the body of research currently underway to address the long-term declines in an iconic species of the American landscape. The research integrates insights across scales, from a single population in Central Oregon experiencing variability in climate and microhabitats over a sub-decadal period to multiple populations and subspecies arrayed across the entire North American continent that have been shaped by anthropogenic climate change over more than a century. In doing so, this work also addresses logistical concerns in how size is measured in birds and addresses a long-standing debate over the multiple potential drivers of Bergmann’s Rule, a fundamental ecogeographical rule found in every ecology textbook

Superconducting Order Parameter in Bi-Layer Cuprates: Occurrence of π\pi Phase Shifts in Corner Junctions

We study the order parameter symmetry in bi-layer cuprates such as YBaCuO, where interesting $\pi$ phase shifts have been observed in Josephson junctions. Taking models which represent the measured spin fluctuation spectra of this cuprate, as well as more general models of Coulomb correlation effects, we classify the allowed symmetries and determine their associated physical properties. $\pi$ phase shifts are shown to be a general consequence of repulsive interactions, independent of whether a magnetic mechanism is operative. While it is known to occur in d-states, this behavior can also be associated with (orthorhombic) s-symmetry when the two sub-band gaps have opposite phase. Implications for the magnitude of $T_c$ are discussed.Comment: 5 pages, RevTeX 3.0, 9 figures (available upon request

Phenomenological BCS theory of the high-TcT_c cuprates

A BCS model characterized by a phenomenological pair potential with on-site ($V_0$), nearest ($V_1$), and next nearest ($V_2$) neighbour coupling constants, and an empirical quasiparticle dispersion taken from angle-resolved photoemission spectra is considered. The model can consistently explain the experimental data concerning the pair state of the hole doped cuprates. Three ingredients are required to make the interpretation possible: the existence of flat bands, a very small effective on-site repulsion, and a slightly dominating effective nnn attraction $V_2$ of the order of 60-80meV with a ratio $V_2/V_1 \approx 1.5$.Comment: 13 pages, uuencoded Postscrip

Macroscopic Symmetry Group Describes Josephson Tunneling in Twinned Crystals

A macroscopic symmetry group describing the superconducting state of an orthorhombically twinned crystal of YBCO is introduced. This macroscopic symmetry group is different for different symmetries of twin boundaries. Josephson tunneling experiments performed on twinned crystals of YBCO determine this macroscopic symmetry group and hence determine the twin boundary symmetry (but do not experimentally determine whether the microscopic order parameter is primarily d- or s-wave). A consequence of the odd-symmetry twin boundaries in YBCO is the stability of vortices containing one half an elementary flux quantum at the intersection of a twin boundary and certain grain boundaries.Comment: 6 pages, to be published in the Proceedings of the MOS96 Conference in the Journal of Low Temperature Physic

Degenerate ground state and anomalous flux hysteresis in an YBa2Cu3O7 grain boundary r.f. SQUID

We report measurements of the flux hysteresis curves and trapped flux distribution in an YBa2Cu3O7 r.f. SQUID containing two closely spaced grain boundary Josephson junctions in parallel. Broadening of the flux distribution from T = 15 K to 30 K is followed by a bifurcation at T = 35 K which corresponds to a degenerate ground state. Above T ~ 40 K the bifurcation disappears, the flux distribution narrows significantly and small secondary loops appear in the hysteresis curves. This behaviour can be modelled qualitatively if we assume a temperature dependent second harmonic term in the current-phase relationship of the junctions.Comment: 10 pages, 7 figure

Orthorhombically Mixed s and dx2−y2_{x^2-y^2} Wave Superconductivity and Josephson Tunneling

The effect of orthorhombicity on Josephson tunneling in high T$_c$ superconductors such as YBCO is studied for both single crystals and highly twinned crystals. It is shown that experiments on highly twinned crystals experimentally determine the symmetry of the superconducting twin boundaries (which can be either even or odd with respect to a reflection in the twinning plane). Conversely, Josephson experiments on highly twinned crystals can not experimentally determine whether the superconductivity is predominantly $s$-wave or predominantly $d$-wave. The direct experimental determination of the order-parameter symmetry by Josephson tunneling in YBCO thus comes from the relatively few experiments which have been carried out on untwinned single crystals.Comment: 5 pages, RevTeX file, 1 figure available on request ([email protected]