2,095 research outputs found
Epidemiology of coagulase-negative staphylococci intramammary infection in dairy cattle and the effect of bacteriological culture misclassification
Data-based estimates of interannual sea–air CO<sub>2</sub>flux variations 1957–2020 and their relation to environmental drivers
Remote sensing applications to resource problems in South Dakota
The author has identified the following significant results. Change in the vegetative structure was taking place in the Black Hills. Temporal analysis of the areal extent of open meadows was accomplished using black and white and color infrared aerial photography. A reduction of nearly 1100 hectares of open meadows was determined using photointerpretation. Techniques were developed for the management of meandering lakes, including use of LANDSAT imagery for continuous monitoring, classification of hydrophytes on low altitude CIR imagery, and planning and evaluation of improvements and multiple uses on aerial photography and photo mosaics. LANDSAT data were analyzed statistically from small and entire study scene areas to determine the effect of soils stratifications of corn signatures. Band 5 early season and band 7 later season recorded the strongest evidence of the influence of soils on corn signatures. Significant strata were determined by a multiple range test
Analytical approximation for the sphere-sphere Coulomb potential
A simple analytical expression, which closely approximates the Coulomb
potential between two uniformly charged spheres, is presented. This expression
can be used in the optical potential semiclassical analyses which require that
the interaction be analytic on and near the real r-axis.Comment: 4 pages including 3 figures and 1 tabl
What applying growthmixture modeling can tell us about predictors of number line estimation
Number line estimation tasks have been considered a good indicator of mathematical competency for many years and are traditionally analyzed by fitting individual regression curves to individual responders. We innovate on this technique by applying growth mixture modeling and compare it to traditional regression using a sample of 2nd graders (n = 325) who completed both 0–20 and 0–100 number line tasks. We explore the effects of gender, special education needs, and migration background. Using growth mixture modeling, more children were identified as logarithmic responders than were identified using regressions. Growth mixture modeling was able to identify the significant effects of gender on class membership for both tasks, and of special education needs for the 0–20 task. Overall, growth mixture modeling provided a more complete picture of individual response patterns than traditional regression techniques. We discuss the implications of these findings and provide recommendations for future researchers to use growth mixture modeling with future number line task analyses
Young people, inequality and violence during the COVID-19 lockdown in Uganda
This working paper reports findings from a qualitative study on how response measures during the early stages of the COVID-19 pandemic in Uganda have affected the lives of adolescent young people. The study was conducted as part of a broader research project: Contexts of Violence in Adolescence Cohort Study (CoVAC), with data collected through mobile phone interviews in May-June 2020 with 18 girls and 16 boys (mainly aged 16-19 years) who have been participants in our longitudinal study. The data are contextualized within longitudinal biographical narratives of these young people that have been developed since 2018 and which helped us to illuminate the significance of the crisis in their everyday lives. The analysis shows how effects on young people of the lockdown varied according to gender, location, mobility and socio-economic background, amplifying inequalities and creating the conditions for multiple forms of violence
Escape Behavior of Quantum Two-Particle Systems with Coulomb Interactions
Quantum escapes of two particles with Coulomb interactions from a confined
one-dimensional region to a semi-infinite lead are discussed by the probability
of particles remaining in the confined region, i.e. the survival probability,
in comparison with one or two free particles. For free-particle systems the
survival probability decays asymptotically in power as a function of time. On
the other hand, for two-particle systems with Coulomb interactions it shows an
exponential decay in time. A difference of escape behaviors between Bosons and
Fermions is considered as quantum effects of identical two particles such as
the Pauli exclusion principle. The exponential decay in the survival
probability of interacting two particles is also discussed in a viewpoint of
quantum chaos based on a distribution of energy level spacings.Comment: 10 pages, 7 figure
Model estimates of metazoans' contributions to the biological carbon pump
Funding: This work was supported by the Centre for Ocean Life, a VKR Centre of Excellence funded by the Villum Foundation, and by the Gordon and Betty Moore Foundation (grant no. 5479). André W. Visser was funded in part through the Horizon 2020 project ECOTIP (grant no. 869383). Andrew S. Brierley and Roland Proud were funded in part through the EU BG3 project “SUMMER” and BG8 project “Mission Atlantic”. Collated echo-sounder data obtained from the British Oceanographic Data Centre (BODC) included observations made during the Atlantic Meridional Transect. The Atlantic Meridional Transect (AMT) is funded by the UK Natural Environment Research Council through its National Capability Long-term Single Centre Science Programme, Climate Linked Atlantic Sector Science (grant number NE/R015953/1).The daily vertical migrations of fish and other metazoans actively transport organic carbon from the ocean surface to depth, contributing to the biological carbon pump. We use an oxygen-constrained, game-theoretic food-web model to simulate diel vertical migrations and estimate near-global (global ocean minus coastal areas and high latitudes) carbon fluxes and sequestration by fish and zooplankton due to respiration, fecal pellets, and deadfalls. Our model provides estimates of the carbon export and sequestration potential for a range of pelagic functional groups, despite uncertain biomass estimates of some functional groups. While the export production of metazoans and fish is modest (∼20 % of global total), we estimate that their contribution to carbon sequestered by the biological pump (∼800 PgC) is conservatively more than 50 % of the estimated global total (∼1300 PgC) and that they have a significantly longer sequestration timescale (∼250 years) than previously reported for other components of the biological pump. Fish and multicellular zooplankton contribute about equally to this sequestered carbon pool. This essential ecosystem service could be at risk from both unregulated fishing on the high seas and ocean deoxygenation due to climate change.Publisher PDFPeer reviewe
Intraspecific and biogeographical variation in foliar fungal communities and pathogen damage of native and invasive Phragmites australis
AimRecent research has highlighted that the relationship between species interactions and latitude can differ between native and invasive plant taxa, generating biogeographical heterogeneity in community resistance to plant invasions. In the first study with foliar pathogens, we tested whether co‐occurring native and invasive lineages of common reed (Phragmites australis) exhibit non‐parallel latitudinal gradients in foliar fungal communities, pathogen susceptibility and damage, and whether these biogeographical patterns can influence the success of invasion.LocationNorth America.Time period2015–2017.Major taxa studiedPerennial grass P. australis.MethodsWe surveyed 35 P. australis field populations, spanning 17° latitude and comprising four phylogeographical lineages, including one endemic to North America and one invasive from Europe. For each population, we quantified the percentage of leaf pathogen damage and cultured fungi from diseased leaves, which we identified using molecular tools. To assess whether latitudinal gradients in pathogen damage had a genetic basis, we inoculated plants from 73 populations with four putative pathogens in a complementary common garden experiment and measured P. australis susceptibility (i.e., diseased leaf area).ResultsWe isolated 84 foliar fungal taxa. Phragmites australis lineage influenced fungal community composition but not diversity. Despite the invasive European P. australis lineage being the least susceptible to three of the four pathogens tested in the common garden experiment, pathogen damage in the field was similar between native and invasive lineages, providing no evidence that release from foliar pathogens contributes to the success of invasion. Genetically based latitudinal gradients in pathogen susceptibility observed in the common garden were isolate specific and obscured by local environmental conditions in the field, where pathogen damage was threefold higher for northern compared with southern populations, regardless of lineage.Main conclusionsOur results highlight that host plant lineage and genetically based biogeographical gradients strongly influence foliar fungal communities and pathogen susceptibility, but do not translate to patterns of pathogen damage observed in the field.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/155999/1/geb13097.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/155999/2/geb13097_am.pd
- …