1,028 research outputs found
Identification of environmentally stable QTL for resistance against Leptosphaeria maculans in oilseed rape (Brassica napus)
© The Author(s) 2015. This article is published with open access at Springerlink.com. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.Phoma stem canker, caused by Leptosphaeria maculans, is a disease of world-wide importance on oilseed rape (Brassica napus). Quantitative trait locus (QTL) mediated resistance against L. maculans in B. napus is considered to be race non-specific and potentially durable. Identification and evaluation of QTL for resistance to L. maculans is important for breeding oilseed rape cultivars with durable resistance. An oilseed rape mapping population was used to detect QTL for resistance against L. maculans in five winter oilseed rape field experiments under different environments. A total of 17 QTL involved in âfieldâ quantitative resistance against L. maculans were detected and collectively explained 51% of the phenotypic variation. The number of QTL detected in each experiment ranged from two to nine and individual QTL explained 2 to 25% of the phenotypic variation. QTL Ă environment interaction analysis suggested that six of these QTL were less sensitive to environmental factors, so they were considered to be stable QTL. Markers linked to these stable QTL will be valuable for selection to breed for effective resistance against L. maculans in different environments, which will contribute to sustainable management of the disease.Peer reviewe
Assessing Student Participation at School: Developing a Multidimensional Scale
In the past few years there has been a growing interest in student participation at school, and in whether participation is connected with student wellbeing or with academic success. One problem when studying student participation is that it seems to mean different things to different people. For some people it is just about students attending school and going to lessons. For others it is about students making decisions about things that matter to them, or being part of âstudent voiceâ activities at school. Another problem is that we do not have good ways to measure how well schools are doing at student participation, with tools that take account of the different ways that students can participate. This article reports how a new tool has been created to measure student participation. The new tool is called the Student Participation Scale. It was created in New South Wales (NSW), Australia. The researchers read books and articles on student participation. They also talked to school staff and students to find out what student participation meant to them, and they asked them about what questions should go into the tool. Once they created the Student Participation Scale, the researchers tested it on 1,435 secondary school students. The Scale asks 38 questions to measure six types or âelementsâ of student participation:
Students working together with peers and school staff,
Students having a voice about schooling,
Students having a say with influential people at school,
Students having influence on decisions made at school,
Students having a voice about school activities outside of the classroom, and
Students having choice.
These elements of student participation were the same for boys and girls, for different grade or year groups, for students who spoke English as a second language, for students from an Indigenous background, and for students with a disability. The Scale was also consistent and valid. That is, it measured what the researchers said it would measure. The Student Participation Scale is easy and free for schools to use. It can be used to measure which elements of participation are happening most, and which ones schools might try to improve. There is also a guidebook that has instructions and tips for using the Scale in schools
Buried solutions:How Maya urban life substantiates soil connectivity
Soils are a pivot of sustainable development. Yet, urban planning decisions persist in compromising the usability of the urban soils resource. Urban land cover expansion to accommodate an increasing population results in soil sealing. Concealment of and physical obstructions to soils prevent urban populations from engaging with their soil dependency. The concept of soil connectivity recognises that nurturing mutually beneficial soilâsociety relations is an essential dimension for achieving soil security. The concentrated populations of urban environments acutely require productive soilâsociety relations and offer the greatest potential for enhancing soil connectivity. Soil connectivity remains notably under-researched, however, resulting in deficient evidence to substantiate exactly how soil connectivity can contribute to sustaining urban life. The entanglement of soil and urban development has been critical throughout history, but seldom recognised in soil security discourse. We review the manifestation of effective soil connectivity in Precolumbian lowland Maya tropical urbanism. Archaeological evidence reveals, first, that lowland Maya urban settlement patterns largely preserved the availability, proximity, and accessibility of soils in the subdivision and configuration of urban open space. Second, Maya urban life included practices that proactively contributed to the formation of soils by adding to the stock of soils and improving beneficial soil properties of the thin and often nutrient-poor soils resulting from the regionally dominant karstic lithology. Third, a range of Maya landscape modifications and engineering practices enabled the preservation and protection of soils within urban environments. We derive evidence-based insights on an urban tradition that endured for well over two millennia by incorporating intensive soilâsociety relationships to substantiate the concept of soil connectivity. Inspiring urban planning to stimulate soil connectivity through enhancing the engagement with soils in urban life would promote soil security
A Numerical Investigation of the Effects of Classical Phase Space Structure on a Quantum System
We present a detailed numerical study of a chaotic classical system and its
quantum counterpart. The system is a special case of a kicked rotor and for
certain parameter values possesses cantori dividing chaotic regions of the
classical phase space. We investigate the diffusion of particles through a
cantorus; classical diffusion is observed but quantum diffusion is only
significant when the classical phase space area escaping through the cantorus
per kicking period greatly exceeds Planck's constant. A quantum analysis
confirms that the cantori act as barriers. We numerically estimate the
classical phase space flux through the cantorus per kick and relate this
quantity to the behaviour of the quantum system. We introduce decoherence via
environmental interactions with the quantum system and observe the subsequent
increase in the transport of quantum particles through the boundary.Comment: 15 pages, 22 figure
Evolution of genomes, host shifts and the geographic spread of SARS-CoV and related coronaviruses
Severe acute respiratory syndrome (SARS) is a novel human illness caused by a previously unrecognized coronavirus (CoV) termed SARS-CoV. There are conflicting reports on the animal reservoir of SARS-CoV. Many of the groups that argue carnivores are the original reservoir of SARS-CoV use a phylogeny to support their argument. However, the phylogenies in these studies often lack outgroup and rooting criteria necessary to determine the origins of SARS-CoV. Recently, SARS-CoV has been isolated from various species of Chiroptera from China (e.g., Rhinolophus sinicus) thus leading to reconsideration of the original reservoir of SARS-CoV. We evaluated the hypothesis that SARS-CoV isolated from Chiroptera are the original zoonotic source for SARS-CoV by sampling SARS-CoV and non-SARS-CoV from diverse hosts including Chiroptera, carnivores, artiodactyls and humans. Regardless of alignment parameters, optimality criteria, or isolate sampling, the resulting phylogenies clearly show that the SARS-CoV was transmitted to small carnivores well after the epidemic of SARS in humans that began in late 2002. The SARS-CoV isolates from small carnivores in Shenzhen markets form a terminal clade that emerged recently from within the radiation of human SARS-CoV. There is evidence of subsequent exchange of SARS-CoV between humans and carnivores. In addition SARS-CoV was transmitted independently from humans to farmed pigs (Sus scrofa). The position of SARS-CoV isolates from Chiroptera are basal to the SARS-CoV clade isolated from humans and carnivores. Although sequence data indicate that Chiroptera are a good candidate for the original reservoir of SARS-CoV, the structural biology of the spike protein of SARS-CoV isolated from Chiroptera suggests that these viruses are not able to interact with the human variant of the receptor of SARS-CoV, angiotensin-converting enzyme 2 (ACE2). In SARS-CoV study, both visually and statistically, labile genomic fragments and, putative key mutations of the spike protein that may be associated with host shifts. We display host shifts and candidate mutations on trees projected in virtual globes depicting the spread of SARS-CoV. These results suggest that more sampling of coronaviruses from diverse hosts, especially Chiroptera, carnivores and primates, will be required to understand the genomic and biochemical evolution of coronaviruses, including SARS-CoV.Fil: Janies, Daniel. Ohio State University; Estados UnidosFil: Habib, Farhat. Ohio State University; Estados UnidosFil: Alexandrov, Boyan. Ohio State University; Estados UnidosFil: Hill, Andrew. University of Colorado; Estados UnidosFil: Pol, Diego. Museo PaleontolĂłgico Egidio Feruglio; Argentina. Ohio State University; Estados Unidos. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; Argentin
Research needs for optimising wastewater-based epidemiology monitoring for public health protection
Wastewater-based epidemiology (WBE) is an unobtrusive method used to observe patterns in illicit drug use, poliovirus, and severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). The pandemic and need for surveillance measures have led to the rapid acceleration of WBE research and development globally. With the infrastructure available to monitor SARS-CoV-2 from wastewater in 58 countries globally, there is potential to expand targets and applications for public health protection, such as other viral pathogens, antimicrobial resistance (AMR), pharmaceutical consumption, or exposure to chemical pollutants. Some applications have been explored in academic research but are not used to inform public health decision-making. We reflect on the current knowledge of WBE for these applications and identify barriers and opportunities for expanding beyond SARS-CoV-2. This paper critically reviews the applications of WBE for public health and identifies the important research gaps for WBE to be a useful tool in public health. It considers possible uses for pathogenic viruses, AMR, and chemicals. It summarises the current evidence on the following: (1) the presence of markers in stool and urine; (2) environmental factors influencing persistence of markers in wastewater; (3) methods for sample collection and storage; (4) prospective methods for detection and quantification; (5) reducing uncertainties; and (6) further considerations for public health use
Control of Dynamical Localization
Control over the quantum dynamics of chaotic kicked rotor systems is
demonstrated. Specifically, control over a number of quantum coherent phenomena
is achieved by a simple modification of the kicking field. These include the
enhancement of the dynamical localization length, the introduction of classical
anomalous diffusion assisted control for systems far from the semiclassical
regime, and the observation of a variety of strongly nonexponential lineshapes
for dynamical localization. The results provide excellent examples of
controlled quantum dynamics in a system that is classically chaotic and offer
new opportunities to explore quantum fluctuations and correlations in quantum
chaos.Comment: 9 pages, 7 figures, to appear in Physical Review
The road to deterministic matrices with the restricted isometry property
The restricted isometry property (RIP) is a well-known matrix condition that
provides state-of-the-art reconstruction guarantees for compressed sensing.
While random matrices are known to satisfy this property with high probability,
deterministic constructions have found less success. In this paper, we consider
various techniques for demonstrating RIP deterministically, some popular and
some novel, and we evaluate their performance. In evaluating some techniques,
we apply random matrix theory and inadvertently find a simple alternative proof
that certain random matrices are RIP. Later, we propose a particular class of
matrices as candidates for being RIP, namely, equiangular tight frames (ETFs).
Using the known correspondence between real ETFs and strongly regular graphs,
we investigate certain combinatorial implications of a real ETF being RIP.
Specifically, we give probabilistic intuition for a new bound on the clique
number of Paley graphs of prime order, and we conjecture that the corresponding
ETFs are RIP in a manner similar to random matrices.Comment: 24 page
Chaos in a double driven dissipative nonlinear oscillator
We propose an anharmonic oscillator driven by two periodic forces of
different frequencies as a new time-dependent model for investigating quantum
dissipative chaos. Our analysis is done in the frame of statistical ensemble of
quantum trajectories in quantum state diffusion approach. Quantum dynamical
manifestation of chaotic behavior, including the emergence of chaos, properties
of strange attractors, and quantum entanglement are studied by numerical
simulation of ensemble averaged Wigner function and von Neumann entropy.Comment: 9 pages, 18 figure
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