2,163 research outputs found

    Perceptions of Transactional and Transformational Leaders According to Gender

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    The lack of females occupying leadership positions in the modern workplace has prompted the research of this study. In order to better understand the perceptions that exist regarding successful leadership, this study was conducted with the intention of understanding individual leadership style through the Multifactor Leadership Questionnaire, which measures transactional and transformational leadership styles (Bass and Avolio, 1993). 64 male and female participants, made up of 36 students and 28 individuals in the workforce ages 18-61 with an average age of 31 answered 21 questions to assess their leadership style and 1 to measure who they perceived as a successful leader, with responses coded by gender of responder and response. This study aimed to assess whether males identified more with transactional leadership and females with transformational leadership style, which would confirm current research conducted in the field. The Chi Squared statistical analysis test results showed that 72.4% of males displayed transformational leadership styles, along with 82.9% of females displaying this same style, which showed a lack of significance between gender and difference in leadership style. However, in response to the question asking to identify a successful leader, results showed that most individuals of both gender wrote down a male leader

    Minimum requirements for feedback enhanced force sensing

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    The problem of estimating an unknown force driving a linear oscillator is revisited. When using linear measurement, feedback is often cited as a mechanism to enhance bandwidth or sensitivity. We show that as long as the oscillator dynamics are known, there exists a real-time estimation strategy that reproduces the same measurement record as any arbitrary feedback protocol. Consequently some form of nonlinearity is required to gain any advantage beyond estimation alone. This result holds true in both quantum and classical systems, with non-stationary forces and feedback, and in the general case of non-Gaussian and correlated noise. Recently, feedback enhanced incoherent force sensing has been demonstrated [Nat. Nano. \textbf{7}, 509 (2012)], with the enhancement attributed to a feedback induced modification of the mechanical susceptibility. As a proof-of-principle we experimentally reproduce this result through straightforward filtering.Comment: 5 pages + 2 pages of Supplementary Informatio

    Spatial variation of the physical conditions of molecular gas in galaxies

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    Multi-line studies of CO-12, CO-13, C-18O, HCN, and HCO(+) at 3 mm, 1.3 mm, and 0.8 mm using the Institute for Radio Astronomy in the Millimeter range (IRAM) 30 m telescope, with the IRAM superconductor insulator superconductor (SIS) receivers and the Max Planck Institute for External Physics (MPE) 350 GHz SIS receiver, show that the densities and temperatures of molecular gas in external galaxies change significantly with position. CO-12 measures the densities and temperature of diffuse interclump molecular gas, but not the bulk of the molecular gas. Simple one-component models, with or without external heating, cannot account for the weakness of the CO-12 J = 3 to 2 line relative to J = 2 to 1 and J = 1 to 0. CO-12 does not trace the bulk of the molecular gas, and optical depth effects obviate a straightforward interpretation of CO-12 data. Instead, researchers turned to the optically thin CO isotopes and other molecular species. Isotopic CO lines measure the bulk of the molecular gas, and HCN and HCO(+) pick out denser regions. Researchers find a warm ridge of gas in IC 342 (Eckart et al. 1989), denser gas in the starburst nucleus of IC 342, and a possible hot-spot in NGC 2903. In IC 342, NGC 2146, and NGC 6764, the CO-13 J = 2 to 1 line is subthermally populated, implying gas densities less than or equal to 10(exp 4) cm(-3)

    High angular resolution mm- and submm-observations of dense molecular gas in M82

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    Researchers observed CO(7-6), CO(3-2), HCN(3-2) and HCO+(3-2) line emission toward the starburst nucleus of M82 and have obtained an upper limit to H13CN(3-2). These are the first observations of the CO(7-6), HCN(3-2) and HCO+(3-2) lines in any extragalactic source. Researchers took the CO(7-6) spectrum in January 1988 at the Infrared Telescope Facility (IRTF) with the Max Planck Institute for Extraterrestrial Physics/Univ. of California, Berkeley 800 GHz Heterodyne Receiver. In March 1989 researchers used the Institute for Radio Astronomy in the Millimeter range (IRAM) 30 m telescope to observe the CO(3-2) line with the new MPE 350 GHz Superconductor Insulator Superconductor (SIS) receiver and the HCN(3-2) and HCO+(3-2) lines with the (IRAM) 230 GHz SIS receiver (beam 12" FWHM, Blundell et al. 1988). The observational parameters are summarized

    Dense, Parsec-Scale Clumps Near the Great Annihilator

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    We report on Combined Array for Research in Millimeter-Wave Astronomy and James Clerk Maxwell Telescope observations toward the Einstein source 1E 1740.7–2942, a low-mass X-ray binary commonly known as the "Great Annihilator." The Great Annihilator is known to be near a small, bright molecular cloud in a region largely devoid of emission in ^(12)CO surveys of the Galactic center. This region is of interest because it is interior to the dust lanes which may be the shock zones where atomic gas from the HI nuclear disk is converted into molecular gas. We find that the region is populated with a large number of dense (n ~ 10^5 cm^(–3)) regions of excited gas with small filling factors. The gas appears to have turbulent support and may be the result of sprays of material from collisions in the shock zone. We estimate that ~(1-3) × 10^5 M⊙ of shocked gas resides in our r ~ 3', Δv_(LSR) = 100 km s^(–1) field. If this gas has recently shocked and is interior to the inner Lindblad resonance of the dominant bar, it is in transit to the x_2 disk, suggesting that a significant amount of mass may be transported to the disk by a low filling factor population of molecular clouds with low surface brightness in larger surveys

    Cover crops improve ground cover in a very dry season

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    Take home messages • Previous trials have shown cover crops can increase stored fallow water and improve crop performance and returns in northern farming systems • A cover crop in a long fallow (14 months) in a dry season allowed improved ground cover with no net deficit in soil water. The extra ground cover improved the opportunity to deep plant wheat. • A cover crop in a short fallow had a water cost that translated to a yield penalty. • When the sorghum stopped growing in dry conditions it continued to use water, for no biomass (or cover) increase when it wasn’t sprayed out

    Dense, Parsec-Scale Clumps near the Great Annihilator

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    We report on Combined Array for Research in Millimeter-Wave Astronomy (CARMA) and James Clerk Maxwell Telescope (JCMT) observations toward the Einstein source 1E 1740.7-2942, a LMXB commonly known as the "Great Annihilator." The Great Annihilator is known to be near a small, bright molecular cloud on the sky in a region largely devoid of emission in 12-CO surveys of the Galactic Center. The region is of interest because it is interior to the dust lanes which may be the shock zones where atomic gas from HI nuclear disk is converted into molecular gas. We find that the region is populated with a number of dense (n ~ 10^5 cm^-3) regions of excited gas with small filling factors, and estimate that up to 1-3 x 10^5 solar masses of gas can be seen in our maps. The detection suggests that a significant amount of mass is transported from the shock zones to the GC star-forming regions in the form of small, dense bundles.Comment: 26 pages, 7 figures, accepted for publication by the Astrophysical Journal, abstract abridge

    Modelling Rock Fracture Induced By Hydraulic Pulses

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    Soft cyclic hydraulic fracturing has become an effective technology used in subsurface energy extraction which utilises cyclic hydraulic flow pressure to fracture rock. This new technique induces fatigue of rock to reduce the breakdown pressure and potentially the associated risk of seismicity. To control the fracturing process and achieve desirable fracture networks for enhanced permeability, the rock response under cyclic hydraulic stimulation needs to be understood. However, the mechanism for cyclic stimulation-induced fatigue of rock is rather unclear and to date there is no implementation of fatigue degradation in modelling the rock response under hydraulic cyclic loading. This makes accurate prediction of rock fracture under cyclic hydraulic pressure impossible. This paper develops a numerical method to model rock fracture induced by hydraulic pulses with consideration of rock fatigue. The fatigue degradation is based on S–N curves (S for cyclic stress and N for cycles to failure) and implemented into the constitutive relationship for fracture of rock using in-house FORTRAN scripts and ABAQUS solver. The cohesive crack model is used to simulate discrete crack propagation in the rock which is coupled with hydraulic flow and pore pressure capability. The developed numerical model is validated via experimental results of pulsating hydraulic fracturing of the rock. The effects of flow rate and frequency of cyclic injection on borehole pressure development are investigated. A new loading strategy for pulsating hydraulic fracturing is proposed. It has been found that hydraulic pulses can reduce the breakdown pressure of rock by 10–18% upon 10–4000 cycles. Using the new loading strategy, a slow and steady rock fracture process is obtained while the failure pressure is reduced
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