829 research outputs found

    Creating a community of learners among college faculty through the use of reflective practice

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    Verification of a Dual-State Extended Kalman Filter with Lidar-Enabled Autonomous Hazard-Detection for Planetary Landers

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    This thesis presents a mathematical model for a LIDAR-enabled Terrain- and Hazard-Relative Navigation sensor and the design and implementation of a dual-state extended Kalman filter. The extended Kalman filter equations are presented in summary. Mathematical models for an altimeter, a velocimeter, a star tracker, and a lidar-enabled mapping/tracking sensor are presented in depth. An explanation of the software designed for computer simulation is included. It is proved through this analysis that, when implemented as part of a well-tuned extended Kalman Filter and in combination with other sensors, the proposed model for a lidar-enabled mapping/tracking sensor significantly reduces estimation error. This enables accurate navigation capable of precision descent-to-landing scenarios

    Department of Insurance

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    Divorce and Real Property on American Indian Reservations: Lessons for First Nations and Canada

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    Four case studies of American Indian nations' treatment of matrimonial real property disputes under formal tribal law, customary law, state law, and some mixtures are presented. Derivative lessons suggest that First Nations, supported by the Government of Canada, ought to develop their own rules and adjudication mechanisms to address these disputes.Quatre études de cas sur la façon dont les nations améridiennes traitent les disputes pour les biens immobiliers matrimoniaux sous la loi tribale formelle, le droit coutumier, le droit interne et quelques mélanges sont présentés. Des leçons dérivées suggÚrent que les PremiÚres nations, appuyées par le gouvernement du Canada, devraient développer leurs propres rÚgles et méchanismes d'adjudication pour adresser ces disputes

    Seizing the Future: Why Some Native Nations Do and Others Don't

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    This study examines the question of why is it that some Native nations seize upon the nation building strategy and take effective control of their futures while others do not. We find that foundational change in a community arises when the external and internal conditions a people face interact with their interpretations of their situation, producing a new, shared "story" of what is possible, and how it can be achieved. The keys to changing a community's "story" are found in proactive decisions to alter internal and external situations, acquire concrete knowledge of the feasible, build on the community's cultural assets, and exercise leadership—especially in educating the people in a new vision.

    IL-1ÎČ, IL-18, and eicosanoids promote neutrophil recruitment to pore-induced intracellular traps following pyroptosis

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    Inflammasomes activate caspase-1, initiating a lytic form of programmed cell death termed pyroptosis, which is an important innate immune defense mechanism against intracellular infections. We recently demonstrated in a mouse infection model of pyroptosis that instead of releasing bacteria into the extracellular space, bacteria remain trapped within the pyroptotic cell corpse, termed the pore-induced intracellular trap (PIT). This trapping mediates efferocytosis of the PIT and associated bacteria by neutrophils; bacteria are subsequently killed via neutrophil ROS. Using this pyroptosis model, we now show that the pro-inflammatory cytokines IL-1ÎČ and IL-18 and inflammatory lipid mediators termed eicosanoids are required for effective clearance of bacteria downstream of pyroptosis. We further show that IL-1ÎČ, IL-18, and eicosanoids affect this in part by mediating neutrophil recruitment to the PIT. This is in addition to our prior findings that complement is also important to attract neutrophils. Thus, the PIT initiates a robust and coordinated innate immune response involving multiple mediators that attract neutrophils to efferocytose the PIT and its entrapped bacteria

    A Survey of Merger Remnants II: The Emerging Kinematic and Photometric Correlations

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    This paper is the second in a series exploring the properties of 51 {\it optically} selected, single-nuclei merger remnants. Spectroscopic data have been obtained for a sub-sample of 38 mergers and combined with previously obtained infrared photometry to test whether mergers exhibit the same correlations as elliptical galaxies among parameters such as stellar luminosity and distribution, central stellar velocity dispersion (σ\sigma∘_{\circ}), and metallicity. Paramount to the study is to test whether mergers lie on the Fundamental Plane. Measurements of σ\sigma∘_{\circ} have been made using the Ca triplet absorption line at 8500 {\AA} for all 38 mergers in the sub-sample. Additional measurements of σ\sigma∘_{\circ} were made for two of the mergers in the sub-sample using the CO absorption line at 2.29 \micron. The results indicate that mergers show a strong correlation among the parameters of the Fundamental Plane but fail to show a strong correlation between σ\sigma∘_{\circ} and metallicity (Mg2_{2}). In contrast to earlier studies, the σ\sigma∘_{\circ} of the mergers are consistent with objects which lie somewhere between intermediate-mass and luminous giant elliptical galaxies. However, the discrepancies with earlier studies appears to correlate with whether the Ca triplet or CO absorption lines are used to derive σ\sigma∘_{\circ}, with the latter almost always producing smaller values. Finally, the photometric and kinematic data are used to demonstrate for the first time that the central phase-space density of mergers are equivalent to elliptical galaxies. This resolves a long-standing criticism of the merger hypothesis.Comment: Accepted Astronomical Journal (to appear in January 2006

    Assessing Landscape Constraints on Species Abundance: Does the Neighborhood Limit Species Response to Local Habitat Conservation Programs?

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    Landscapes in agricultural systems continue to undergo significant change, and the loss of biodiversity is an ever-increasing threat. Although habitat restoration is beneficial, management actions do not always result in the desired outcome. Managers must understand why management actions fail; yet, past studies have focused on assessing habitat attributes at a single spatial scale, and often fail to consider the importance of ecological mechanisms that act across spatial scales. We located survey sites across southern Nebraska, USA and conducted point counts to estimate Ring-necked Pheasant abundance, an economically important species to the region, while simultaneously quantifying landscape effects using a geographic information system. To identify suitable areas for allocating limited management resources, we assessed land cover relationships to our counts using a Bayesian binomial-Poisson hierarchical model to construct predictive Species Distribution Models of relative abundance. Our results indicated that landscape scale land cover variables severely constrained or, alternatively, facilitated the positive effects of local land management for Ring-necked Pheasants

    The X-ray Size-Temperature Relation for Intermediate Redshift Galaxy Clusters

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    We present the first measurements of the X-ray size-temperature (ST) relation in intermediate redshift (z~0.30) galaxy clusters. We interpret the local ST relation (z~0.06) in terms of underlying scaling relations in the cluster dark matter properties, and then we use standard models for the redshift evolution of those dark matter properties to show that the ST relation does not evolve with redshift. We then use ROSAT HRI observations of 11 clusters to examine the intermediate redshift ST relation; for currently favored cosmological parameters, the intermediate redshift ST relation is consistent with that of local clusters. Finally, we use the ST relation and our evolution model to measure angular diameter distances; with these 11 distances we evaluate constraints on Omega_M and Omega_L which are consistent with those derived from studies of Type Ia supernovae. The data rule out a model with Omega_M=1 and Omega_L=0 with 2.5 sigma confidence. When limited to models where Omega_M+Omega_L=1, these data are inconsistent with Omega_M=1 with 3 sigma confidence.Comment: ApJ: submitted April 7, accepted June 28, to appear Dec 1 (vol 544

    SuperMassive Black Holes in Bulges

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    We present spatially extended gas kinematics at parsec-scale resolution for the nuclear regions of four nearby disk galaxies, and model them as rotation of a gas disk in the joint potential of the stellar bulge and a putative central black hole. The targets were selected from a larger set of long-slit spectra obtained with the Hubble Space Telescope as part of the Survey of Nearby Nuclei with STIS (SUNNS). They represents the 4 galaxies (of 24) that display symmetric gas velocity curves consistent with a rotating disk. We derive the stellar mass distribution from the STIS acquisition images adopting the stellar mass-to-light ratio normalized so as to match ground-based velocity dispersion measurements over a large aperture. Subsequently, we constrain the mass of a putative black hole by matching the gas rotation curve, following two distinct approaches. In the most general case we explore all the possible disk orientations, alternatively we constrain the gas disk orientation from the dust-lane morphology at similar radii. In the latter case the kinematic data indicate the presence of a central black hole for three of the four objects, with masses of 10^7 - 10^8 solar masses, representing up to 0.025 % of the host bulge mass. For one object (NGC2787) the kinematic data alone provide clear evidence for the presence of a central black hole even without external constraints on the disk orientation. These results illustrate directly the need to determine black-hole masses by differing methods for a large number of objects, demonstrate that the variance in black hole/bulge mass is much larger than previously claimed, and reinforce the recent finding that the black-hole mass is tightly correlated with the bulge stellar velocity dispersion.Comment: 26 pages, 11 Postscript figures, accepted for publication on Ap
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