839 research outputs found

    Stability Analysis of Slide at Milepost 152.7, I 64, Carter County

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    A visual inspection of a slide near Milepost 153 on I 64 was made April 11, 1972, and reported in a memorandum prepared by B. H. Banks on April 12, 1972. The Division of Research made recommendations for correcting this situation in a memorandum to A. R. Romine on June 30, 1972. These recommendations were based on a limited field investigation and a stability analysis of a proposed berm to be located near Station 3483+00. In a letter dated August 18, 1972, Mr. A. J. Horner of FHWA requested borings be made at the site to establish rock depth and to obtain samples for triaxial testing. That correspondence indicated that, to be eligible for FAI participation, a more complete analysis of the slip would be needed. Results of the present investigation which conform to the FHWA request are presented herein. Translatory slope stability analyses were not performed since the circular slope stability analysis was more applicable in this particular situation. Slope stability computations (Bishop\u27s circular method) were carried out in terms of effective stress using shear strength parameters obtained from consolidated, isotropic, undrained triaxial tests with pore pressure measurements. The major objective of the study was to check a remedial solution previously proposed (see APPENDIX). The investigation was conducted under Research Study KYP-72-38 entitled Landslides and maintenance project SP 22-538-28L

    Stability of a Side-Hill Embankment

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    The report submitted herein is a case history describing observations and in-depth analyses made at a highway site involving a massive, unstable side-hill embankment located on I-64 in Boyd County. The in-depth study was initiated in January 1973. The I-64 site was selected for study because it contained several design, construction and maintenance features as well as soil types that are typical of many highway embankments in Kentucky. Side-hill fill situations are common design problems and oftentimes have required extensive maintenance after construction. Major objectives of the study were to 1) determine the causes of instability of the I-64 embankment, 2) check a remedial solution previously reported for the I-64 site and present alternative solutions if necessary, 3) determine short-term (initial) and long-term safety factors of the embankment slopes, and 4) compare theoretical shear surfaces obtained from a slope stability program based on Bishop\u27s simplified method of slices with actual failure points obtained from slope indicators and surface observations. All slope stability computations were carried out in terms of effective stress using shear strength parameters obtained from consolidated, isotropic, undrained triaxial tests with pore pressure measurements

    Blood pressure and cardiac autonomic adaptations to isometric exercise training: A randomized sham‐controlled study

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    Isometric exercise training (IET) is increasingly cited for its role in reducing resting blood pressure (BP). Despite this, few studies have investigated a potential sham effect attributing to the success of IET, thus dictating the aim of the present study. Thirty physically inactive males (n = 15) and females (n = 15) were randomly assigned into three groups. The IET group completed a wall squat intervention at 95% peak heart rate (HR) using a prescribed knee joint angle. The sham group performed a parallel intervention, but at an intensity (<75% peak HR) previously identified to be inefficacious over a 4-week training period. No-intervention controls maintained their normal daily activities. Pre- and post-measures were taken for resting and continuous blood pressure and cardiac autonomic modulation. Resting clinic and continuous beat-to-beat systolic (−15.2 ± 9.2 and −7.3 ± 5.6 mmHg), diastolic (−4.6 ± 5 and −4.5 ± 5.1), and mean (−7 ± 4.2 and −7.5 ± 5.3) BP, respectively, all significantly decreased in the IET group compared to sham and no-intervention control. The IET group observed a significant decrease in low-frequency normalized units of heart rate variability concurrent with a significant increase in high-frequency normalized units of heart rate variability compared to both the sham and no-intervention control groups. The findings of the present study reject a nonspecific effect and further support the role of IET as an effective antihypertensive intervention. Clinical Trials ID: NCT05025202

    Blood pressure and cardiac autonomic adaptations to isometric exercise training: A randomized sham-controlled study

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    Isometric exercise training (IET) is increasingly cited for its role in reducing resting blood pressure (BP). Despite this, few studies have investigated a potential sham effect attributing to the success of IET, thus dictating the aim of the present study. Thirty physically inactive males (n=15) and females (n=15) were randomly assigned into 3 groups. The IET group completed a wall-squat intervention at 95% peak heart rate (HR) using a prescribed knee joint angle. The sham group performed a parallel intervention, but at an intensity (<75% peak HR) previously identified to be inefficacious over a 4-week training period. No-intervention controls maintained their normal daily activities. Pre- and post-measures were taken for resting and continuous blood pressure and cardiac autonomic modulation. Resting clinic and continuous beat to beat systolic (-15.2±9.2 and -7.3±5.6 mmHg), diastolic (-4.6±5 and -4.5±5.1) and mean (-7±4.2 and -7.5±5.3) BP, respectively, all significantly decreased in the IET group compared to sham and no-intervention control. The IET group observed a significant decrease in low frequency normalised units of heart rate variability concurrent with a significant increase in high frequency normalised units of heart rate variability compared to both the sham and no-intervention control groups. The findings of the present study reject a non-specific effect and further support the role of IET as an effective anti-hypertensive intervention

    Flood plain management through allocation of land uses–a dynamic programming model

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    Despite heroic structural measures, flood damages continue to rise. This research develops a means for identifying more nearly optimal patterns of land use with particular reference to timing, depth, and duration of flooding. The major premise is that flood plain management is best viewed as a problem of allocating land uses to land parcels. A dynamic programming model is developed to determine what combination of downstream uses, which require flood protection, and upstream uses, which may increase runoff or provide protection through longer water retention, should be encouraged. The dynamic programming model and an associated simplified routing technique are demonstrated on a real watershed. Desirable extensions of the model are identified. One major result of the project is the realization of a need to classify watersheds by the degree of effective interdependence among land use decisions so as to determine the most appropriate types of analytical model s and public sector interventions for particular cases. Thinking about flood management as a problem of land use allocation is shown to be a fruitful conceptualization for exploring the issues, for developing models, and for identifying appropriate public sector interventions.U.S. Geological SurveyU.S. Department of the InteriorOpe

    Model for floodplain management in urbanizing areas

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    A target land use pattern found using a dynamic programming model is shown to be a useful reference for comparing the success of floodplain management policies. At least in the test case, there is interdependence in the land use allocation for floodplain management--that is, a good solution includes some reduction of current land use in the floodplain and some provision of detention storage. For the test case, current floodplain management policies are not sufficient; some of the existing floodplain use should be removed. Although specific land use patterns are in part sensitive to potential error in land value data and to inaccuracy in the routing model, the general conclusion that some existing use must be removed is stable within the range of likely error. Trend surface analysis is shown to be a potentially useful way of generating bid price data for use in land use allocation models. Sensitivity analysis of the dynamic programming model with respect to routing of hydrographs is conducted through simulation based on expected distributions of error.U.S. Geological SurveyU.S. Department of the InteriorOpe

    Global Star Formation Rate Density over 0.7<z<1.9

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    We determine the global star formation rate density at 0.7<z<1.9 using emission-line selected galaxies identified in Hubble Space Telescope Near Infrared Camera and Multi-Object Spectrograph (HST-NICMOS) grism spectroscopy observations. Observing in pure parallel mode throughout HST Cycles 12 and 13, our survey covers ~104 arcmin2 from which we select 80 galaxies with likely redshifted Ha emission lines. In several cases, a somewhat weaker [OIII] doublet emission is also detected. The Ha luminosity range of the emission-line galaxy sample is 4.4 x 10^41 < L(Ha) < 1.5 x 10^43 erg/s. In this range, the luminosity function is well described by a Schechter function with phi* = (4.24\pm3.55) x 10^-3 Mpc^-3, L* = (2.88\pm1.58) x 10^42 erg/s, and alpha = -1.39\pm0.43. We derive a volume-averaged star formation rate density of 0.138\pm0.058 Msun/yr/Mpc3 at z=1.4 without an extinction correction. Subdividing the redshift range, we find star formation rate densities of 0.088\pm0.056 Msun/yr/Mpc3 at z=1.1 and 0.265\pm0.174 Msun/yr/Mpc3 at z=1.6. The overall star formation rate density is consistent with previous studies using Ha when the same average extinction correction is applied, confirming that the cosmic peak of star formation occurs at z>1.5.Comment: Accepted for publication in Ap

    Stochastic Gravitational Wave Background from Coalescing Binary Black Holes

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    We estimate the stochastic gravitational wave (GW) background signal from the field population of coalescing binary stellar mass black holes (BHs) throughout the Universe. This study is motivated by recent observations of BH-Wolf-Rayet star systems and by new estimates in the metallicity abundances of star forming galaxies that imply BH-BH systems are more common than previously assumed. Using recent analytical results of the inspiral-merger-ringdown waveforms for coalescing binary BH systems, we estimate the resulting stochastic GW background signal. Assuming average quantities for the single source energy emissions, we explore the parameter space of chirp mass and local rate density required for detection by advanced and third generation interferometric GW detectors. For an average chirp mass of 8.7M⊙M_{\odot}, we find that detection through 3 years of cross-correlation by two advanced detectors will require a rate density, r0≄0.5Mpc−3Myr−1r_0 \geq 0.5 \rm{Mpc}^{-3} \rm{Myr}^{-1}. Combining data from multiple pairs of detectors can reduce this limit by up to 40%. Investigating the full parameter space we find that detection could be achieved at rates r0∌0.1Mpc−3Myr−1r_0 \sim 0.1 \rm{Mpc}^{-3} \rm{Myr}^{-1} for populations of coalescing binary BH systems with average chirp masses of ∌15M⊙\sim 15M_{\odot} which are predicted by recent studies of BH-Wolf-Rayet star systems. While this scenario is at the high end of theoretical estimates, cross-correlation of data by two Einstein Telescopes could detect this signal under the condition r0≄10−3Mpc−3Myr−1r_0 \geq 10^{-3} \rm{Mpc}^{-3} \rm{Myr}^{-1}. Such a signal could potentially mask a primordial GW background signal of dimensionless energy density, ΩGW∌10−10\Omega_{\rm{GW}}\sim 10^{-10}, around the (1--500) Hz frequency range.Comment: 22 pages, 5 figures, 2 tables, Accepted for publication by Ap

    Building a stochastic template bank for detecting massive black hole binaries

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    Coalescence of two massive black holes is the strongest and most promising source for LISA. In fact, gravitational signal from the end of inspiral and merger will be detectable throughout the Universe. In this article we describe the first step in the two-step hierarchical search for gravitational wave signal from the inspiraling massive BH binaries. It is based on the routinely used in the ground base gravitational wave astronomy method of filtering the data through the bank of templates. However we use a novel Monte-Carlo based (stochastic) method to lay a grid in the parameter space, and we use the likelihood maximized analytically over some parameters, known as F-statistic, as a detection statistic. We build a coarse template bank to detect gravitational wave signals and to make preliminary parameter estimation. The best candidates will be followed up using Metropolis-Hasting stochastic search to refine the parameter estimation. We demonstrate the performance of the method by applying it to the Mock LISA data challenge 1B (training data set).Comment: revtex4, 8 figure

    A 15-Year Analysis of Early and Late Autologous Hematopoietic Stem Cell Transplant in Relapsed, Aggressive, Transformed, and Nontransformed Follicular Lymphoma

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    AbstractAutologous stem cell transplant (ASCT) has been shown to be an effective treatment for follicular lymphoma (FL). We explored our experience in ASCT for FL among all patients treated over a 15-year period from diagnosis through their entire treatment history including relapse post ASCT. All patients who underwent an unpurged ASCT for relapsed, advanced FL between June 1990 and December 2000 were analyzed. After salvage therapy they received melphalan/etoposide/total body irradiation, BCNU, etoposide, cytarabine, melphalan (BEAM), or cyclophosphamide BCNU etoposide (CBV) as conditioning for the ASCT. One hundred thirty-eight patients with a median age of 48 years and a median follow-up of 7.6 years were analyzed. The majority were of the subtype grade 1, nontransformed (FL-NT), having had 1 prior chemotherapy. The progression-free (PFS) and overall survival (OS) of the FL-NT at 10 years were 46% and 57%, respectively, and at 5 years for the transformed (FL-T) were 25% and 56%, respectively, of which only the PFS was significantly different (P = .007). The median OS from diagnosis was 16 years for the FL-NT. ASCT positively altered the trend of shorter remissions with subsequent chemotherapies, and there was no difference in OS between those who had 1, 2, or >2 chemotherapies prior to ASCT. Salvage therapy for relapse post ASCT was effective (OS >1 year) in a third of patients. Unpurged ASCT is an effective tool in the treatment of relapsed, aggressive FL-NT and FL-T, is superior to retreatment with standard chemotherapy, is effective at various stages of treatment, is likely to have a beneficial influence on the natural history of this disease, and the disease is amenable to salvage therapy post-ASCT relapse
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