1,704 research outputs found

    Meta-awareness during day and night: the relationship between mindfulness and lucid dreaming.

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    The present study explored the relationship between lucidity in dreams (awareness of dreams while dreaming) and mindfulness during wakefulness, also considering meditation as a possible moderating variable. An online survey was completed by 528 respondents, of whom 386 (73.1%) had lucid dream experiences. The reported frequency of lucid dreams was found to be positively related to higher dispositional mindfulness in wakefulness. This relationship was only present in those participants who reported acquaintance with meditation. Regarding the dimensions of mindfulness, lucid dream frequency was more strongly associated with mindful presence rather than acceptance. The findings support the notion of an existing relationship between lucidity in dreams and mindfulness during wakefulness, yet it remains unclear whether the relationship is influenced by actual meditation practice or whether it reflects some natural predispositions. Future studies should examine the role of different meditation practices, investigate personality variables that might influence the relationship, and explore how different facets of mindfulness and lucidity interrelate. Keywords: lucid dreaming; mindfulness; meditatio

    Summer Dormancy and Survival of Tall Fescue in Relation to Endophyte Presence

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    True summer dormancy in temperate perennial grasses is the ability to survive summer stresses by ceasing growth and senescing vegetative tissues independently of water supply, as opposed to summer-active grasses, which respond to rains by continuing growth, but senesce during droughts (Volaire and Norton 2006). Summer dormancy is a common drought-escape mechanism for Mediterranean-origin perennial grasses, but is also being considered as a potentially useful trait in semiarid to humid zones whose climates are not strictly Mediterranean, but where temperate grass survival is threatened by summer heat and water deficits (Malinowski et al. 2005). Moreover, summer dormancy may provide a mechanism for adapting to climate change patterns that exacerbate summer stresses (West et al. 2009). Tall fescue [Lolium arundinaceum (Schreb.) S.J. Darbyshire] populations exhibit a range of summer dormancy potentials from nondormant (summer active) to varying levels of incomplete dormancy, but not complete dormancy (Norton et al. 2006). Summer drought survival of tall fescue is generally aided by symbiosis with a fungal endophyte [Neotyphodium coenophialum (Morgan-Jones & Gams) Glenn, Bacon & Hanlin comb.], and this endophyte is endemic in nearly all native populations of tall fescue (West 1994). Little is known of the influence of the endophyte on the expression of summer dormancy in their grass hosts or of the role of endophytes in host drought survival. We investigated the influence of environment and endophyte presence on expression of summer dormancy and survival in tall fescue in relation to expression of biochemical protectants

    Breeding Cool-Season Forage Grasses for a Warming Climate

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    In many parts of the world, changing climatic conditions are resulting in increased temperatures and more variable precipitation, intensifying the duration and severity of drought, especially in summer. Warming climate is considered one reason for the increasing failure of traditional, summer-active cool-season perennial grasses at the margin of their zone of adaptation in naturally C4 grass-dominated ecosystems of the Southern Great Plains of the USA. Two cool-season perennial forage grasses orchardgrass (Dactylis glomerata L.) and tall fescue (Lolium arundinaceum (Schreb.) Darbysh.) are of major economic and ecological importance in these regions. In 2008, we initiated a breeding program of summer-dormant (Mediterranean) cool-season perennial grasses originating from the Mediterranean Basin, including tall fescue, orchardgrass, and perennial ryegrass. In this publication, we present breeding history and morphological characteristics of cv. Yonatan (also known under research name TAL-02), a new cultivar of summer-dormant tall fescue. Recurrent selection cycles were conducted to develop cv. Yonatan during 2007-2010. Evaluations were performed on several locations across north Texas, Australia and New Zealand during 2015-2020. Yonatan tall fescue has improved forage production and persistence compared with check cultivars Flecha and Chisholm. It also differs from them in terms of wider leaves, earlier maturity, and development of a bulbous storage organ at the base of the tiller. Yonatan is adapted to changing climatic conditions in the Southern Great Plains of the USA, Australia, and New Zealand

    Modified ultrafast thermometer UFT-M and temperature measurements during Physics of Stratocumulus Top (POST)

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    A modified UFT-M version of the ultrafast airborne thermometer UFT, aimed at in-cloud temperature measurements, was designed for the Physics of Stratocumulus Top (POST) field campaign. Improvements in its construction resulted in the sensor's increased reliability, which provided valuable measurements in 15 of the 17 flights. Oversampling the data allowed for the effective correction of the artefacts resulting from the interference with electromagnetic transmissions from on-board avionic systems and the thermal noise resulting from the sensor construction. The UFT-M records, when averaged to the 1.4 and 55 m resolutions, compared to the similar records of a thermometer in a Rosemount housing, indicate that the housing distorts even low-resolution airborne temperature measurements. Data collected with the UFT-M during the course of POST characterise the thermal structure of stratocumulus and capping inversion with the maximum resolution of ~1 cm. In this paper, examples of UFT-M records are presented and discussed

    Entrainment rates and microphysics in POST stratocumulus

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    The article of record as published may be located at http://dx.doi.org/10.1002/jgrd.50878An aircraft field study (POST; Physics of Stratocumulus Top) was conducted off the central California coast in July and August 2008 to deal with the known difficulty of measuring entrainment rates in the radiatively important stratocumulus (Sc) prevalent in that area. The Center for Interdisciplinary Remotely-Piloted Aircraft Studies Twin Otter research aircraft flew 15 quasi-Lagrangian flights in unbroken Sc and carried a full complement of probes including three high-data-rate probes: ultrafast temperature probe, particulate volume monitor probe, and gust probe. The probes’ colocation near the nose of the Twin Otter permitted estimation of entrainment fluxes and rates with an in-cloud resolution of 1m. Results include the following: Application of the conditional sampling variation of classical mixed layer theory for calculating the entrainment rate into cloud top for POST flights is shown to be inadequate for most of the Sc. Estimated rates resemble previous results after theory is modified to take into account both entrainment and evaporation at cloud top given the strong wind shear and mixing at cloud top. Entrainment rates show a tendency to decrease for large shear values, and the largest rates are for the smallest temperature jumps across the inversion. Measurements indirectly suggest that entrained parcels are primarily cooled by infrared flux divergence rather than cooling from droplet evaporation, while detrainment at cloud top causes droplet evaporation and cooling in the entrainment interface layer above cloud top.NSF supported H. Gerber, G. Frick, and S. Malinowski (ATM-0735121, AGS-1020445), D. Khelif (ATM-0734323), and S. Krueger (ATM-0735118). The Office of Naval Research and the Naval Postgraduate School supported in part the deployment of the Twin Otter aircraft

    Anomalous Paramagnetic Effects in the Mixed State of LuNi2B2C

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    Anomalous paramagnetic effects in dc magnetization were observed in the mixed state of LuNi2B2C, unlike any reported previously. It appears as a kink-like feature for H > 30 kOe and becomes more prominent with increasing field. A specific heat jump at the corresponding temperature suggests that the anomaly is due to a true bulk transition. A magnetic flux transition from a square to an hexagonal lattice is consistent with the anomaly.Comment: 5 pages, 4 figure

    Demagnetization of Quantum Dot Nuclear Spins: Breakdown of the Nuclear Spin Temperature Approach

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    The physics of interacting nuclear spins arranged in a crystalline lattice is typically described using a thermodynamic framework: a variety of experimental studies in bulk solid-state systems have proven the concept of a spin temperature to be not only correct but also vital for the understanding of experimental observations. Using demagnetization experiments we demonstrate that the mesoscopic nuclear spin ensemble of a quantum dot (QD) can in general not be described by a spin temperature. We associate the observed deviations from a thermal spin state with the presence of strong quadrupolar interactions within the QD that cause significant anharmonicity in the spectrum of the nuclear spins. Strain-induced, inhomogeneous quadrupolar shifts also lead to a complete suppression of angular momentum exchange between the nuclear spin ensemble and its environment, resulting in nuclear spin relaxation times exceeding an hour. Remarkably, the position dependent axes of quadrupolar interactions render magnetic field sweeps inherently non-adiabatic, thereby causing an irreversible loss of nuclear spin polarization.Comment: 15 pages, 3 figure

    Anisotropy of Thermal Conductivity and Possible Signature of the Fulde-Ferrell-Larkin-Ovchinnikov state in CeCoIn_5

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    We have measured the thermal conductivity of the heavy-fermion superconductor CeCoIn_5 in the vicinity of the upper critical field, with the magnetic field perpendicular to the c axis. Thermal conductivity displays a discontinuous jump at the superconducting phase boundary below critical temperature T_0 ~ 1 K, indicating a change from a second to first order transition and confirming the recent results of specific heat measurements on CeCoIn_5. In addition, the thermal conductivity data as a function of field display a kink at a field H_k below the superconducting critical field, which closely coincides with the recently discovered anomaly in specific heat, tentatively identified with the appearance of the spatially inhomogeneous Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) superconducting state. Our results indicate that the thermal conductivity is enhanced within the FFLO state, and call for further theoretical investigations of the order parameter's real space structure (and, in particular, the structure of vortices) and of the thermal transport within the inhomogeneous FFLO state.Comment: 19 pages, 6 figures, submitted to Prhys. Rev.

    Magnetism and unconventional superconductivity in Cen_nMm_mIn3n+2m_{3n+2m} heavy-fermion crystals

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    We review magnetic, superconducting and non-Fermi-liquid properties of the structurally layered heavy-fermion compounds Cen_nMm_mIn3n+2m_{3n+2m} (M=Co, Rh, Ir). These properties suggest d-wave superconductivity and proximity to an antiferromagetic quantum-critical point.Comment: submitted 23rd International Conference on Low Temperature Physics (LT-23), Aug. 200
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