5,335 research outputs found
Corrigendum. Maars to calderas: end-members on a spectrum of explosive volcanic depressions
A corrigendum on
Maars to calderas: end-members on a spectrum of explosive volcanic depressions
by Palladino, D. M., Valentine, G. A., Sottili, G., and Taddeucci, J. (2015). Front. Earth Sci. 3:36.
doi: 10.3389/feart.2015.00036
Reason for Corrigendum:
In the original article (Palladino et al., 2015), there was an error in Figure 1. The vertical axis
of the qualitative plot reported erroneously “ratio of juvenile to lithic materials in deposits outside
of depression”. The correct wording is as follows: “ratio of juvenile to total (i.e., juvenile+lithic)
materials in deposits outside of depression”. In fact, as it was reported correctly in the text, the
amount of juvenilematerial (i.e., scoria or pumice) deposited ouside the different types of explosive
volcanic depressions increases from zero (i.e., no juvenile, all lithic products), as is the case of
hydrothermal (phreatic) explosion craters, to become largely dominant over the lithic component
in the case of ash flow deposits associated with large overpressure collapse calderas. The corrected Figure 1 appears below. The authors apologize for this error and state that this does not change the scientific conclusions of the article in any way
Ready, set, oh no? Prepare for possible online accessibility issues before they arise
Trying to make your online resources more accessible but aren\u27t sure where the vendor\u27s interface might cause problems? Do you collect Accessibility Compliance Reports (sometimes referred to as a Voluntary Product Accessibility Template or VPAT) and file it away without doing anything with the information contained within? Find out how the Online Resources and Services Librarian at the University of North Dakota’s School of Medicine and Health Sciences Library Resources has partnered with UND’s Equity Compliance and Education Manager to take accessibility compliance to the next level. We’ve augmented the basic University requirement to check a box into a more comprehensive process that ensures we’re proactively attending to our users’ current and future needs. We work internally and with vendors to identify and track the potential failing points of our online resources as identified in their ACR. We then, prior to purchase approval or renewal, develop a plan to mitigate the accessibility barriers within the platform and provide equally effective alternative access to the material. Once the resource is made available within our ILS, we inform users of known accessibility barriers and make sure they know how to contact us with questions or for assistance. In this lightning talk, we’ll discuss going beyond basic internal requirements to establish more rigorous measures that better meets users where they are and before they know they need help. You’ll discover how to identify and track potential problems, how to communicate to your users regarding accessibility concerns, and how to maintain contact with your vendors and publishers to advocate for your users
The C(3P) + NH3 reaction in interstellar chemistry: II. Low temperature rate constants and modeling of NH, NH2 and NH3 abundances in dense interstellar clouds
A continuous supersonic flow reactor has been used to measure rate constants
for the C + NH3 reaction over the temperature range 50 to 296 K. C atoms were
created by the pulsed laser photolysis of CBr4. The kinetics of the title
reaction were followed directly by vacuum ultra-violet laser induced
fluorescence (VUV LIF) of C loss and through H formation. The experiments show
unambiguously that the reaction is rapid at 296 K, becoming faster at lower
temperatures, reaching a value of 1.8 10-10 cm3 molecule-1 s-1 at 50 K. As this
reaction is not currently included in astrochemical networks, its influence on
interstellar nitrogen hydride abundances is tested through a dense cloud model
including gas-grain interactions. In particular, the effect of the
ortho-to-para ratio of H2 which plays a crucial role in interstellar NH3
synthesis is examined
Species Segregation and Functional Groups in the Hill Country of New Zealand
In the hill country of New Zealand, the soil-sward relationship on hill microrelief was studied. Three categories of slope or microsites were distinguished: low, medium and high. The hypothesis was that soil variables of neighbouring microsites differ, and because of this, there is a segregation of species or functional groups of species between the microsites. Soil features, botanical composition and total annual yield were measured in the slope categories in two similar paddocks; one of which had received long-term phosphorus fertilisation and a non-fertilised paddock. ANOVA, cluster analysis and canonical variate analysis were performed on the data. Unsaturated hydraulic conductivity, slope, bulk density, volumetric soil moisture, soil total nitrogen content, soil phosphorus content and soil compressibility explained most of the variation between microsites. All the measured variables showed that differences amongst microsites were larger than between paddocks. The soil of the low slopes was more developed and fertile than the soil of the other microsites. From the botanical composition, seven functional groups were determined. Low slope microsites yielded significantly greater dry matter than medium and high slopes and were dominated by high fertility grasses and Lolium perenne. Low fertility species and Agrostis capillaris dominated the high slope category. Dicotyledons that colonised high fertility and species with low presence were indifferent to changes in the soil variables. The group of medium fertility species was intermediate between the high and low fertility groups. In conclusion, environmental variables segregated species and functional groups. Species and functional groups differed in ecological strategy. High competitors dominated in environments with high availability of resource. Environments with low resources availability were dominated by stress tolerant species
Microrheology with optical tweezers: data analysis
We present a data analysis procedure that provides the solution to a long-standing issue in microrheology studies, i.e. the evaluation of the fluids' linear viscoelastic properties from the analysis of a finite set of experimental data, describing (for instance) the time-dependent mean-square displacement of suspended probe particles experiencing Brownian fluctuations. We report, for the first time in the literature, the linear viscoelastic response of an optically trapped bead suspended in a Newtonian fluid, over the entire range of experimentally accessible frequencies. The general validity of the proposed method makes it transferable to the majority of microrheology and rheology techniques
Embodied learning: Responding to AIDS in Lesotho's education sector
This is an Author's Accepted Manuscript of an article published in Children's Geographies, 7(1), 2009. Copyright @ 2009 Taylor & Francis, available online at: http://www.tandfonline.com/doi/abs/10.1080/14733280802630981.In contrast to pre-colonial practices, education in Lesotho's formal school system has historically assumed a Cartesian separation of mind and body, the disciplining of students' bodies serving principally to facilitate cognitive learning. Lesotho has among the highest HIV-prevalence rates worldwide, and AIDS has both direct and indirect impacts on the bodies of many children. Thus, students' bodies can no longer be taken for granted but present a challenge for education. Schools are increasingly seen as a key point of intervention to reduce young people's risk of contracting the disease and also to assist them to cope with its consequences: there is growing recognition that such goals require more than cognitive learning. The approaches adopted, however, range from those that posit a linear and causal relationship between knowledge, attitudes and practices (so-called ‘KAP’ approaches, in which the role of schools is principally to inculcate the pre-requisite knowledge) to ‘life skills programmes’ that advocate a more embodied learning practice in schools. Based on interviews with policy-makers and practitioners and a variety of documentary sources, this paper examines a series of school-based AIDS interventions, arguing that they represent a less radical departure from ‘education for the mind’ than might appear to be the case. The paper concludes that most interventions serve to cast on children responsibility for averting a social risk, and to ‘normalise’ aberrant children's bodies to ensure they conform to what the cognitively-oriented education system expects
Mutations in the Drosophila melanogaster gene three rows permit aspects of mitosis to continue in the absence of chromatid segregation
We have cloned the three rows (thr) gene, by a combination of chromosome microdissection and P element tagging. We describe phenotypes of embryos homozygous for mutations at the thr locus. Maternal mRNA and protein appear to be sufficient to allow 14 rounds of mitosis in embryos homozygous for thr mutations. However, a small percentage of cells in syncytial blastoderm stage thr embryos sink into the interior of the embryo as if they have failed to divide properly. Following cellularisation all cells complete mitosis 14 normally. All cells become delayed at mitosis 15 with their chromosomes remaining aligned on the spindle in a metaphase-like configuration, even though both cyclins A and B have both been degraded. As cyclin B degradation occurs at the metaphase-anaphase transition, subsequent to the microtubule integrity checkpoint, the delay induced by mutations at the thr locus defines a later point in mitotic progression. Chromosomes in the cells of thr embryos do not undertake anaphase separation, but remain at the metaphase plate. Subsequently they decondense. A subset of nuclei go on to replicate their DNA but there is no further mitotic division
A special simplex in the state space for entangled qudits
Focus is on two parties with Hilbert spaces of dimension d, i.e. "qudits". In
the state space of these two possibly entangled qudits an analogue to the well
known tetrahedron with the four qubit Bell states at the vertices is presented.
The simplex analogue to this magic tetrahedron includes mixed states. Each of
these states appears to each of the two parties as the maximally mixed state.
Some studies on these states are performed, and special elements of this set
are identified. A large number of them is included in the chosen simplex which
fits exactly into conditions needed for teleportation and other applications.
Its rich symmetry - related to that of a classical phase space - helps to study
entanglement, to construct witnesses and perform partial transpositions. This
simplex has been explored in details for d=3. In this paper the mathematical
background and extensions to arbitrary dimensions are analysed.Comment: 24 pages, in connection with the Workshop 'Theory and Technology in
Quantum Information, Communication, Computation and Cryptography' June 2006,
Trieste; summary and outlook added, minor changes in notatio
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