16,849 research outputs found
Constructed wetlands: Treatment of concentrated storm water runoff (part A)
The aim of this research was to assess the treatment efficiencies for gully pot liquor of experimental vertical-
flow constructed wetland filters containing Phragmites australis (Cav.) Trin. ex Steud. (common
reed) and filter media of different adsorption capacities. Six out of 12 filters received inflow water spiked
with metals. For 2 years, hydrated nickel and copper nitrate were added to sieved gully pot liquor to simulate
contaminated primary treated storm runoff. For those six constructed wetland filters receiving heavy
metals, an obvious breakthrough of dissolved nickel was recorded after road salting during the first winter.
However, a breakthrough of nickel was not observed, since the inflow pH was raised to eight after
the first year of operation. High pH facilitated the formation of particulate metal compounds such as nickel
hydroxide. During the second year, reduction efficiencies of heavy metal, 5-days at 20°C N-Allylthiourea
biochemical oxygen demand (BOD) and suspended solids (SS) improved considerably. Concentrations of
BOD were frequently �20 mg/L. However, concentrations for SS were frequently �30 mg/L. These are
the two international thresholds for secondary wastewater treatment. The BOD removal increased over
time due to biomass maturation, and the increase of pH. An analysis of the findings with case-based reasoning
can be found in the corresponding follow-up paper (Part B)
Genes involved in barley yellow dwarf virus resistance of maize
KEY MESSAGE: The results of our study suggest that genes involved in general resistance mechanisms of plants contribute to variation of BYDV resistance in maize. ABSTRACT: With increasing winter temperatures in Europe, Barley yellow dwarf virus (BYDV) is expected to become a prominent problem in maize cultivation. Breeding for resistance is the best strategy to control the disease and break the transmission cycle of the virus. The objectives of our study were (1) to determine genetic variation with respect to BYDV resistance in a broad germplasm set and (2) to identify single nucleotide polymorphism (SNP) markers linked to genes that are involved in BYDV resistance. An association mapping population with 267 genotypes representing the world’s maize gene pool was grown in the greenhouse. Plants were inoculated with BYDV-PAV using viruliferous Rhopalosiphum padi. In the association mapping population, we observed considerable genotypic variance for the trait virus extinction as measured by double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) and the infection rate. In a genome-wide association study, we observed three SNPs significantly [false discovery rate (FDR) = 0.05] associated with the virus extinction on chromosome 10 explaining together 25 % of the phenotypic variance and five SNPs for the infection rate on chromosomes 4 and 10 explaining together 33 % of the phenotypic variance. The SNPs significantly associated with BYDV resistance can be used in marker assisted selection and will accelerate the breeding process for the development of BYDV resistant maize genotypes. Furthermore, these SNPs were located within genes which were in other organisms described to play a role in general resistance mechanisms. This suggests that these genes contribute to variation of BYDV resistance in maize. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00122-014-2400-1) contains supplementary material, which is available to authorized users
Monoids in the mapping class group
In this article we survey, and make a few new observations about, the
surprising connection between sub-monoids of mapping class groups and
interesting geometry and topology in low-dimensions.Comment: 36 pages, 18 figure
Constructed wetlands: Prediction of performance with case-based reasoning (part B)
The aim of this research was to assess the treatment efficiencies for gully pot liquor of experimental vertical-
flow constructed wetland filters containing Phragmites australis (Cav.) Trin. ex Steud. (common reed)
and filter media of different adsorption capacities. Six out of 12 filters received inflow water spiked with
metals. For 2 years, hydrated nickel and copper nitrate were added to sieved gully pot liquor to simulate
contaminated primary treated storm runoff. The findings were analyzed and discussed in a previous paper
(Part A). Case-based reasoning (CBR) methods were applied to predict 5 days at 20°C N-Allylthiourea biochemical
oxygen demand (BOD) and suspended solids (SS), and to demonstrate an alternative method of
analyzing water quality performance indicators. The CBR method was successful in predicting if outflow
concentrations were either above or below the thresholds set for water-quality variables. Relatively small
case bases of approximately 60 entries are sufficient to yield relatively high predictions of compliance of
at least 90% for BOD. Biochemical oxygen demand and SS are expensive to estimate, and can be cost-effectively
controlled by applying CBR with the input variables turbidity and conductivity
Closed formula for the relative entropy of entanglement in all dimensions
The relative entropy of entanglement is defined in terms of the relative
entropy between an entangled state and its closest separable state (CSS). Given
a multipartite-state on the boundary of the set of separable states, we find a
closed formula for all the entangled state for which this state is a CSS. Quite
amazing, our formula holds for multipartite states in all dimensions. In
addition we show that if an entangled state is full rank, then its CSS is
unique. For the bipartite case of two qubits our formula reduce to the one
given in Phys. Rev. A 78, 032310 (2008).Comment: 8 pages, 1 figure, significantly revised; theorem 1 is now providing
necessary and sufficient conditions to determine if a state is CS
Cabling, contact structures and mapping class monoids
In this paper we discuss the change in contact structures as their supporting
open book decompositions have their binding components cabled. To facilitate
this and applications we define the notion of a rational open book
decomposition that generalizes the standard notion of open book decomposition
and allows one to more easily study surgeries on transverse knots. As a
corollary to our investigation we are able to show there are Stein fillable
contact structures supported by open books whose monodromies cannot be written
as a product of positive Dehn twists. We also exhibit several monoids in the
mapping class group of a surface that have contact geometric significance.Comment: 62 pages, 32 figures. Significant expansion of exposition and more
details on some argument
Rate-dependent morphology of Li2O2 growth in Li-O2 batteries
Compact solid discharge products enable energy storage devices with high
gravimetric and volumetric energy densities, but solid deposits on active
surfaces can disturb charge transport and induce mechanical stress. In this
Letter we develop a nanoscale continuum model for the growth of Li2O2 crystals
in lithium-oxygen batteries with organic electrolytes, based on a theory of
electrochemical non-equilibrium thermodynamics originally applied to Li-ion
batteries. As in the case of lithium insertion in phase-separating LiFePO4
nanoparticles, the theory predicts a transition from complex to uniform
morphologies of Li2O2 with increasing current. Discrete particle growth at low
discharge rates becomes suppressed at high rates, resulting in a film of
electronically insulating Li2O2 that limits cell performance. We predict that
the transition between these surface growth modes occurs at current densities
close to the exchange current density of the cathode reaction, consistent with
experimental observations.Comment: 8 pages, 6 fig
Factors impacting readiness to perform secondary population-based triage during the second wave of COVID-19 in Victoria, Australia: Pilot study
Objective: Pandemics generate such a significant demand for care that traditional triage methods can become saturated. Secondary population-based triage (S-PBT) overcomes this limitation. Although the coronavirus disease (COVID-19) pandemic forced S-PBT into operation internationally during the first year of the pandemic, Australian doctors were spared this responsibility. However, the second wave of COVID-19 provides an opportunity to explore the lived experience of preparing for S-PBT within the Australian context. The aim of this study is to explore the lived experience of preparing to operationalize S-PBT to allocate critical care resources during Australia\u27s second wave of COVID-19 in 2020. Methods: Intensivists and emergency physicians working during the second Victorian COVID-19 surge were recruited by purposive non-random sampling. Semi-structured interviews were hosted remotely, recorded, transcribed, and coded to facilitate a qualitative phenomenological analysis. Results: Six interviews were conducted with an equal mix of intensivists and emergency doctors. Preliminary findings from a thematic analysis revealed 4 themes: (1) threat of resources running; (2) informed decision requiring information; (3) making decisions as we always do; and (4) a great burden to carry. Conclusion: This is the first description of this novel phenomenon within Australia and, in doing so, it identified a lack of preparedness to operationalize S-PBT during the second wave of COVID-19 in Australia
Improved Lower Bounds for Locally Decodable Codes and Private Information Retrieval
We prove new lower bounds for locally decodable codes and private information
retrieval. We show that a 2-query LDC encoding n-bit strings over an l-bit
alphabet, where the decoder only uses b bits of each queried position of the
codeword, needs code length m = exp(Omega(n/(2^b Sum_{i=0}^b {l choose i})))
Similarly, a 2-server PIR scheme with an n-bit database and t-bit queries,
where the user only needs b bits from each of the two l-bit answers, unknown to
the servers, satisfies t = Omega(n/(2^b Sum_{i=0}^b {l choose i})). This
implies that several known PIR schemes are close to optimal. Our results
generalize those of Goldreich et al. who proved roughly the same bounds for
linear LDCs and PIRs. Like earlier work by Kerenidis and de Wolf, our classical
lower bounds are proved using quantum computational techniques. In particular,
we give a tight analysis of how well a 2-input function can be computed from a
quantum superposition of both inputs.Comment: 12 pages LaTeX, To appear in ICALP '0
- …