429 research outputs found

    Decomposing tournaments into paths

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    We consider a generalisation of Kelly's conjecture which is due to Alspach, Mason, and Pullman from 1976. Kelly's conjecture states that every regular tournament has an edge decomposition into Hamilton cycles, and this was proved by Kühn and Osthus for large tournaments. The conjecture of Alspach, Mason, and Pullman asks for the minimum number of paths needed in a path decomposition of a general tournament T . There is a natural lower bound for this number in terms of the degree sequence of T and it is conjectured that this bound is correct for tournaments of even order. Almost all cases of the conjecture are open and we prove many of them

    Decomposing tournaments into paths

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    In this work we consider a generalisation of Kelly's conjecture which is due Alspach, Mason, and Pullman from 1976. Kelly's conjecture states that every regular tournament has an edge decomposition into Hamilton cycles, and this was proved by Kühn and Osthus for large tournaments. The conjecture of Alspach, Mason, and Pullman concerns general tournaments and asks for the minimum number of paths needed in an edge decomposition of each tournament into paths. There is a natural lower bound for this number in terms of the degree sequence of the tournament and they conjecture this bound is correct for tournaments of even order. Almost all cases of the conjecture are open and we prove many of them

    Traditional Owners of the Great Barrier Reef: the next generation of Reef 2050 actions

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    In short, this Report: Confirms that there are two options for progressing the integration of Traditional Owner interests in the Reef 2050 Plan. Option 1 (Business As Usual) represents a continuation of the current approach of Government-based review and refinement of the (now 23) Traditional Owner actions in the Reef 2050 Plan. Option 2 (Towards Genuine Co-governance) represents Government taking a far more negotiated approach at the GBR-wide level (and subsequently down to local scales) that applies the principles of Free Prior and Informed Consent. Based on extensive engagement concerning the aspirations of Traditional Owners and their support organisations across the GBR, the overwhelming stated desire and demand is for genuine partnership in the overarching governance of the Reef and far deeper ownership of, and participation in, its active day to day management (Option 2). There is an unambiguous view that the foundations set in the Reef 2050 Plan (Option 1), while a step in the right direction, simply reflect Traditional Owner aspirations in someone else’s planning. Meanwhile, a consistent message from Traditional Owners, fuelled by their existing and emerging rights in sea country, is that this more passive form of involvement cannot continue into the future; that a genuine form of agreement making and active implementation (from GBR to local scales) must emerge

    Palaeoenvironmental and diagenetic reconstruction of a closed-lacustrine carbonate system - the challenging marginal setting of the Miocene Ries Crater Lake (Germany)

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    Chemostratigraphic studies on lacustrine sedimentary sequences provide essential insights on past cyclic climatic events, on their repetition and prediction through time. Diagenetic overprint of primary features often hinders the use of such studies for palaeoenvironmental reconstruction. Here the potential of integrated geochemical and petrographic methods is evaluated to record freshwater to saline oscillations within the ancient marginal lacustrine carbonates of the Miocene Ries Crater Lake (Germany). This area is critical because it represents the transition from shoreline to proximal domains of a hydrologically closed system, affected by recurrent emergent events, representing the boundaries of successive sedimentary cycles. Chemostratigraphy targets shifts related to subaerial exposure and/or climatic fluctuations. Methods combine facies changes with δ13C–δ18O chemostratigraphy from matrix carbonates across five closely spaced, temporally equivalent stratigraphic sections. Isotope composition of ostracod shells, gastropods and cements is provided for comparison. Cathodoluminescence and back‐scatter electron microscopy were performed to discriminate primary (syn‐)depositional, from secondary diagenetic features. Meteoric diagenesis is expressed by substantial early dissolution and dark blue luminescent sparry cements carrying negative δ13C and δ18O. Sedimentary cycles are not correlated by isotope chemostratigraphy. Both matrix δ13C and δ18O range from ca −7·5 to +4·0‰ and show clear positive covariance (R = 0·97) whose nature differs from that of previous basin‐oriented studies on the lake: negative values are here unconnected to original freshwater lacustrine conditions but reflect extensive meteoric diagenesis, while positive values probably represent primary saline lake water chemistry. Noisy geochemical curves relate to heterogeneities in (primary) porosity, resulting in selective carbonate diagenesis. This study exemplifies that ancient lacustrine carbonates, despite extensive meteoric weathering, are able to retain key information for both palaeoenvironmental reconstruction and the understanding of diagenetic processes in relation to those primary conditions. Also, it emphasizes the limitation of chemostratigraphy in fossil carbonates, and specifically in settings that are sensitive for the preservation of primary environmental signals, such as lake margins prone to meteoric diagenesis

    Total Observed Organic Carbon (TOOC): A synthesis of North American observations

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    Measurements of organic carbon compounds in both the gas and particle phases measured upwind, over and downwind of North America are synthesized to examine the total observed organic carbon (TOOC) over this region. These include measurements made aboard the NOAA WP-3 and BAe-146 aircraft, the NOAA research vessel Ronald H. Brown, and at the Thompson Farm and Chebogue Point surface sites during the summer 2004 ICARTT campaign. Both winter and summer 2002 measurements during the Pittsburgh Air Quality Study are also included. Lastly, the spring 2002 observations at Trinidad Head, CA, surface measurements made in March 2006 in Mexico City and coincidentally aboard the C-130 aircraft during the MILAGRO campaign and later during the IMPEX campaign off the northwestern United States are incorporated. Concentrations of TOOC in these datasets span more than two orders of magnitude. The daytime mean TOOC ranges from 4.0 to 456 μgC m^−3 from the cleanest site (Trinidad Head) to the most polluted (Mexico City). Organic aerosol makes up 3–17% of this mean TOOC, with highest fractions reported over the northeastern United States, where organic aerosol can comprise up to 50% of TOOC. Carbon monoxide concentrations explain 46 to 86% of the variability in TOOC, with highest TOOC/CO slopes in regions with fresh anthropogenic influence, where we also expect the highest degree of mass closure for TOOC. Correlation with isoprene, formaldehyde, methyl vinyl ketene and methacrolein also indicates that biogenic activity contributes substantially to the variability of TOOC, yet these tracers of biogenic oxidation sources do not explain the variability in organic aerosol observed over North America. We highlight the critical need to develop measurement techniques to routinely detect total gas phase VOCs, and to deploy comprehensive suites of TOOC instruments in diverse environments to quantify the ambient evolution of organic carbon from source to sink

    Impact of volcanism on the sedimentary record of the Neuquén rift basin, Argentina: towards a cause and effect model

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    The analysis of volcano-sedimentary infill in sedimentary basins constitutes a challenge for basin analysis and hydrocarbon exploration worldwide. In order to understand the contribution of volcanism to the sedimentary record in rift basins, we study the Jurassic effusive-explosive volcanic infill of an inverted extensional depocentre at the Neuquén Basin, Argentina. A cause and effect model that evaluates the relationship between volcanism and sedimentation was devised to develop a conceptual model for the tectono-stratigraphic evolution of this volcanic rift basin. We show how the variations in the volcanism, coupled with the activity of extensional faults, determined the types of volcanic edifices (i.e., composite volcanoes, graben-calderas, and lava fields). Volcanic edifices controlled the stacking patterns of the volcanic units as well as sedimentary systems. The landform of the volcanic edifices, as well as the styles and scales of the eruptions governed the sedimentary input to the basin, setting the main variables of the sedimentary systems, such as provenance, grain size, transport and deposition and geometry. As a result, the contrasting volcaniclastic input, from higher volcaniclastic input to lower volcaniclastic input, associated with different subsidence patterns, determined the high-resolution syn-rift infill patterns of the extensional depocentre. The cause and effect model presented in this study isolates the variables of the volcanic environments that control the sedimentary scenarios. We suggest that, by adjusting the first order input parameters of the model, these cause and effect scenarios could be adapted to similar rift basins, in order to establish predictive facies models with stratigraphic controls, and the impact of volcanism on their stratigraphic records.Fil: D'Elia, Leandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones Geológicas. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Investigaciones Geológicas; ArgentinaFil: Martí, Joan. Consejo Superior de Investigaciones Científicas. Instituto de Ciencias de la Tierra Jaume Almera; EspañaFil: Muravchik, Martin. University Of Bergen; Noruega. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Bilmes, Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico de Geología y Paleontología.; ArgentinaFil: Franzese, Juan Rafael. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones Geológicas. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Investigaciones Geológicas; Argentin

    Atomic characterization of Si nanoclusters embedded in SiO2 by atom probe tomography

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    Silicon nanoclusters are of prime interest for new generation of optoelectronic and microelectronics components. Physical properties (light emission, carrier storage...) of systems using such nanoclusters are strongly dependent on nanostructural characteristics. These characteristics (size, composition, distribution, and interface nature) are until now obtained using conventional high-resolution analytic methods, such as high-resolution transmission electron microscopy, EFTEM, or EELS. In this article, a complementary technique, the atom probe tomography, was used for studying a multilayer (ML) system containing silicon clusters. Such a technique and its analysis give information on the structure at the atomic level and allow obtaining complementary information with respect to other techniques. A description of the different steps for such analysis: sample preparation, atom probe analysis, and data treatment are detailed. An atomic scale description of the Si nanoclusters/SiO2 ML will be fully described. This system is composed of 3.8-nm-thick SiO layers and 4-nm-thick SiO2 layers annealed 1 h at 900°C

    Necessary connections: ‘Feelings photographs’ in criminal justice research

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    Visual representations of prisons and their inmates are common in the news and social media, with stories about riots, squalor, drugs, self-harm and suicide hitting the headlines. Prisoners’ families are left to worry about the implications of such events on their kin, while those incarcerated and less able to understand social cues, norms and rules, are vulnerable to deteriorating mental health at best, to death at worst. As part of the life-story method in my research with offenders who are on the autism spectrum, have mental health problems and/or have learning difficulties, and prisoner’s mothers, I asked participants to take photographs, reflecting upon their experiences. Photographs in this case, were primarily used to help respondents consider and articulate their feelings in follow-up interviews. Notably, seeing (and imagining) is often how we make a connection to something (object or feeling), or someone (relationships), such that images in fiction, news/social media, drama, art, film and photographs can shape the way people think and behave – indeed feel about things and people. Images and representations ought to be taken seriously in researching social life, as how we interpret photographs, paintings, stories and television shows is based on our own imaginings, biography, culture and history. Therefore, we look at and process an image before words escape, by ‘seeing’ and imagining. How my participants and I ‘collaborate’ in doing visual methods and then how we make meaning of the photographs in storying their feelings, is insightful. As it is, I wanted to enable my participants to make and create their own stories via their photographs and narratives, whilst connecting to them, along with my own interpretation and subjectivities

    Ganetespib in combination with pemetrexed-platinum chemotherapy in patients with pleural Mesothelioma (MESO-02) : a phase Ib trial

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    Purpose: Ganetespib, a highly potent, small molecule Heatshock protein 90 inhibitor, has potential efficacy in malignant pleural mesothelioma (MPM) via activity on critical survival pathways and known synergies with antifolates and platinum chemotherapy. We conducted a dose-escalation study to identify the Maximum Tolerated Dose (MTD) of ganetespib in chemotherapy-naïve MPM patients. Experimental Design: MESO-02 (ClinicalTrials.gov: NCT01590160) was a non-randomized, multicentre, phase Ib trial of 3-weekly ganetespib (100 mg/m2, 150 mg/m2, 200 mg/m2; days 1 and 15) with pemetrexed (500 mg/m2; day 1) and cisplatin (75 mg/m2; day 1) or carboplatin (area under concentration-time curve 5; day 1) in MPM patients. Dose-escalation was performed using the 3+3 design (cisplatin) and accelerated titration design (carboplatin). Secondary endpoints included best response, progression-free survival (PFS) and pharmacogenomic analyses. Results: Of 27 patients enroled (cisplatin, n=16; carboplatin, n=11), 3 experienced dose-limiting toxicities: grade 3 nausea (cisplatin, n=1; carboplatin, n=1); grade 2 infusion-related reaction (carboplatin, n=1). Ganetespib's MTD was 200 mg/m2. Partial response was observed in 14/27 patients (52%; 61% in 23 response-evaluable patients) and 13/21 (62%) with epithelioid histology. At the MTD, 10/18 patients (56%) had partial response, 15/18 (83%) had disease control, and median PFS was 6.3 months (95% CI 5.0-10.0). One responder exhibited disease control beyond 50 months. Global Loss of Heterozygosity was associated with shorter time to progression (Hazard Ratio 1.12, 95% CI 1.02-1.24; p=0.018). Conclusions: Ganetespib can be combined safely with pemetrexed and platinum chemotherapy to treat patients with MPM. This class of agent should be investigated in larger randomized studies
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