2,203 research outputs found

    Pictorial display of materials and processes aids in fabricating complex assemblies

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    Method uses assembly consisting of single pictorial display showing cutaway view of assembly, subassemblies identified by name and materials, and processes identified by both specification and commercial design. Display is used in engineering, manufacturing, and personnel training

    Common leadership strategies and practices among authentic senior leaders

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    From the early 2000s onwards, authentic leadership has continued to garner growing interest from academia, the public sector, and across multiple industries. Perhaps the reason for the increased focus on authenticity is the unethical behavior demonstrated by a number of leaders from 2000 to 2010. While there is growing interest in demonstrating authenticity as a situational leadership style or even an inherent trait, there is limited research on what leadership strategies or practices are most effective for authentic leaders. This study was designed to apply a common definition, or set of criteria, to identify leaders that are authentic. Once this group of authentic leaders has been identified, research can be conducted to understand common characteristics, traits, styles, practices, and strategies. Conversely, the opportunity exists to understand what common challenges authentic leaders face to determine mitigation strategies. The findings of this study provided exemplary best practices for leaders in business and other fields. To help ground the study, a detailed literature review of leadership theory, and authentic leadership’s place within the study of leadership, was completed. The historical examination of leadership is important as it adds richness and context to how authenticity has risen to prominence within empirical and theoretical research. This research showed that common leadership strategies and practices among authentic leaders include the ability to connect and engage through honest and transparent storytelling. Authentic leaders are vulnerable and transparent, and they enable and engage people and organizations through sharing a compelling vision. Their core leadership approach of honesty and transparency does not change, but they will flex how direct they are based on the situation and audience. In terms of challenges, authentic senior leaders have a high desire for their authentic approach to be reciprocated, and they can be too demanding. In order to overcome these challenges, they try to manage their stress and use physiological and mental means to manage energy. Authentic senior leaders measure success in terms of business results, talent development, and being recognized. The advice they have for future leader is to be one’s authentic self and to understand one’s personal mission and purpose

    Evaluation of ECMWF water vapour fields by airborne differential absorption lidar measurements: a case study between Brazil and Europe

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    International audienceThree extended airborne Differential Absorption Lidar (DIAL) sections of tropospheric water vapour across the tropical and sub-tropical Atlantic in March 2004 are compared to short-term forecasts of the European Centre for Medium Range Weather Forecasts (ECMWF). The humidity fields between 28° S and 36° N exhibit large inter air-mass gradients and reflect typical transport patterns of low- and mid-latitudes like convection (e.g. Hadley circulation), subsidence and baroclinic development with stratospheric intrusion. These processes re-distribute water vapour vertically such that locations with extraordinary dry/moist air-masses are observed in the lower/upper troposphere, respectively. The mixing ratios range over 3 orders of magnitude. Back-trajectories are used to trace and characterize the observed air-masses. Overall, the observed water vapour distributions are largely reproduced by the short-term forecasts at 0.25° resolution (T799/L91), the correlation ranges from 0.69 to 0.92. Locally, large differences occur due to comparably small spatial shifts in presence of strong gradients. Systematic deviations are found associated with specific atmospheric domains. The planetary boundary layer in the forecast is too moist and to shallow. Convective transport of humidity to the middle and upper troposphere tends to be overestimated. Potential impacts arising from data assimilation and model physics are considered. The matching of air-mass boundaries (transport) is discussed with repect to scales and the representativity of the 2-D sections for the 3-D humidity field. The normalized bias of the model with respect to the observations is 6%, 11% and 0% (moist model biases) for the three along-flight sections, whereby however the lowest levels are excluded

    New genus of Late Cretaceous angel shark

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    29 pages : illustrations ; 26 cm.Three-dimensional Late Cretaceous elasmobranch endoskeletal elements (including palatoquadrates, ceratohyals, braincase fragments, and a series of anterior vertebrae) are described from the Late Cretaceous University of Alabama Harrell Station Paleontological Site (HSPS), Dallas County, Alabama. The material is referred to the extant elasmobranch Family Squatinidae on the basis of several distinctive morphological features. It also exhibits features not shared by any modern or fossil Squatina species or the extinct Late Jurassic squatinid Pseudorhina. A new genus and species is erected, despite there being some uncertainty regarding potential synonymy with existing nominal species previously founded on isolated fossil teeth (curiously, no squatinid teeth have been documented from the HSPS). A preliminary phylogenetic analysis suggests that the new genus falls on the squatinid stem, phylogenetically closer to Squatina than Pseudorhina. The craniovertebral articulation in the new genus exhibits features considered convergent with modern batomorphs (skates and rays), including absence of contact between the posterior basicranium and first vertebral centrum, and a notochordal canal which fails to reach the parachordal basicranium. Supporting evidence that similarities in the craniovertebral articulation of squatinoids and batomorphs are convergent rather than synapomorphic (as "hypnosqualeans") is presented by an undescribed Early Jurassic batomorph, in which an occipital hemicentrum articulates with the first vertebral centrum as in all modern sharklike (selachimorph) elasmobranchs. The fossil suggests instead that the batomorph synarcual evolved by fusion of the anterior basiventral and basidorsal cartilages prior to the reduction of the anterior centra and loss of the occipital hemicentrum, not afterward as predicted by the hypnosqualean hypothesis

    Sensitivity studies for a space-based methane lidar mission

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    Methane is the third most important greenhouse gas in the atmosphere after water vapour and carbon dioxide. A major handicap to quantify the emissions at the Earth's surface in order to better understand biosphere-atmosphere exchange processes and potential climate feedbacks is the lack of accurate and global observations of methane. Space-based integrated path differential absorption (IPDA) lidar has potential to fill this gap, and a Methane Remote Lidar Mission (MERLIN) on a small satellite in polar orbit was proposed by DLR and CNES in the frame of a German-French climate monitoring initiative. System simulations are used to identify key performance parameters and to find an advantageous instrument configuration, given the environmental, technological, and budget constraints. The sensitivity studies use representative averages of the atmospheric and surface state to estimate the measurement precision, i.e. the random uncertainty due to instrument noise. Key performance parameters for MERLIN are average laser power, telescope size, orbit height, surface reflectance, and detector noise. A modest-size lidar instrument with 0.45 W average laser power and 0.55 m telescope diameter on a 506 km orbit could provide 50-km averaged methane column measurement along the sub-satellite track with a precision of about 1% over vegetation. The use of a methane absorption trough at 1.65 ÎĽm improves the near-surface measurement sensitivity and vastly relaxes the wavelength stability requirement that was identified as one of the major technological risks in the pre-phase A studies for A-SCOPE, a space-based IPDA lidar for carbon dioxide at the European Space Agency. Minimal humidity and temperature sensitivity at this wavelength position will enable accurate measurements in tropical wetlands, key regions with largely uncertain methane emissions. In contrast to actual passive remote sensors, measurements in Polar Regions will be possible and biases due to aerosol layers and thin ice clouds will be minimised

    Passive remote sensing of columnar water vapour content above land surfaces. Part I: Theoretical algorithm development - Part II: Comparison of OVID measurements with radiosonde and DIAL measurements

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    Various efforts are currently being made to develop remote sensing techniques for high accuracy determination of atmospheric columnar water vapour content above land surfaces. Most of those algorithms are based on radiative transfer calcu lations, however, which have to be verified by spectral airborne or satellite measurements. Initial verification of a new algorithm with the aid of airborne spectral data using the spectrometer OVID (Optical Visible and near Infrared Detector), an airborne water vapour DIAL (Differential Absorption Lidar), an airc;raft humicap sensor and radiosonde data is performed dUIing a flight experiment over Southern Germany. This water vapour algorithm is also dedicated to the MERIS (MEdium Resolution Imaging Spectrometer) in strument on board ESA's satellite ENVISAT which will be launched 1999. Spatial water vapour gradients of &120 = 0.1 g/cm2 over a distance of 100 km were resolved by applying the OVID measurements. The error estimation of the absolute value of the retrieved water vapour contents poses· some problems due to insufficient additional temporal and spatial radiosonde data. However, the principal feasibility has been prove

    MSSM predictions of the neutral Higgs boson masses and LEP II production cross sections

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    Within the framework of the Minimal Supersymmetric Standard Model (MSSM) the Higgs masses and LEP II production cross sections are calculated for a wide range of the parameter space. In addition, the parameter space restricted by unification, electroweak symmetry breaking and other low energy constraints is considered in detail, in which case the masses of all SUSY partners can be estimated, so that their contributions to the radiative corrections can be calculated. Explicit analytical formulae for these contribution are derived. The radiative corrections from the Yukawa couplings of the third generation are found to dominate over the contributions from charginos and neutralinos. Large Higgs mass uncertainties are due to the top mass uncertainty and the unknown sign of the Higgs mixing parameter. For the low tanb scenario the mass of the lightest Higgs is found to be below 103 GeV for a top mass below 190 GeV. The cross section at a LEP energy of 192 GeV is sufficient to find or exclude this low tanb scenario for a top mass below 180 GeV. For the high tanb scenario only a small fraction of the parameter space can be covered, since the Higgs mass is predicted between 105 and 125 GeV in most cases. At the theoretically possible LEP II energy of 205 GeV part of the parameter space for the large tanb scenario would be accessible
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