Development and testing of cabin sidewall acoustic resonators for the reduction of cabin tone levels in propfan-powered aircraft

The use of Helmholtz resonators to increase the sidewall transmission loss (TL) in aircraft cabin sidewalls is evaluated. Development, construction, and test of an aircraft cabin acoustic enclosure, built in support of the Propfan Test Assessment (PTA) program, is described. Laboratory and flight test results are discussed. Resonators (448) were located between the enclosure trim panels and the fuselage shell. In addition, 152 resonators were placed between the enclosure and aircraft floors. The 600 resonators were each tuned to a propfan fundamental blade passage frequency (235 Hz). After flight testing on the PTA aircraft, noise reduction (NR) tests were performed with the enclosure in the Kelly Johnson Research and Development Center Acoustics Laboratory. Broadband and tonal excitations were used in the laboratory. Tonal excitation simulated the propfan flight test excitation. The resonators increase the NR of the cabin walls around the resonance frequency of the resonator array. Increases in NR of up to 11 dB were measured. The effects of flanking, sidewall absorption, cabin absorption, resonator loading of trim panels, and panel vibrations are presented. Resonator and sidewall panel design and test are discussed

OMCat: Catalogue of Serendipitous Sources Detected with the XMM-Newton Optical Monitor

The Optical Monitor Catalogue of serendipitous sources (OMCat) contains entries for every source detected in the publicly available XMM-Newton Optical Monitor (OM) images taken in either the imaging or ``fast'' modes. Since the OM is coaligned and records data simultaneously with the X-ray telescopes on XMM-Newton, it typically produces images in one or more near-UV/optical bands for every pointing of the observatory. As of the beginning of 2006, the public archive had covered roughly 0.5% of the sky in 2950 fields. The OMCat is not dominated by sources previously undetected at other wavelengths; the bulk of objects have optical counterparts. However, the OMCat can be used to extend optical or X-ray spectral energy distributions for known objects into the ultraviolet, to study at higher angular resolution objects detected with GALEX, or to find high-Galactic-latitude objects of interest for UV spectroscopy.Comment: 25 pages, 22 figures, submitted to PAS

Modeling the Local Warm/Hot Bubble

In this paper we review the modeling of the Local Bubble (LB) with special emphasis on the progress we have made since the last major conference "The Local Bubble and Beyond (I)" held in Garching in 1997. Since then new insight was gained into the possible origin of the LB, with a moving group crossing its volume during the last 10 - 15 Myr being most likely responsible for creating a local cavity filled with hot recombining gas. Numerical high resolution 3D simulations of a supernova driven inhomogeneous interstellar medium show that we can reproduce both the extension of the LB and the OVI column density in absorption measured with FUSE for a LB age of 13.5 - 14.5 Myr. We further demonstrate that the LB evolves like an ordinary superbubble expanding into a density stratified medium by comparing analytical 2D Kompaneets solutions to NaI contours, representing the extension of the local cavity. These results suggest that LB blow-out into the Milky Way halo has occurred roughly 5 Myr ago.Comment: 8 pages, 3 figures, to appear in the proceedings of "The Local Bubble and Beyond II", Philadelphia, USA, April 21-24, 200

Clostridium difficile infection among veterans health administration patients

OBJECTIVETo report on the prevalence and incidence of Clostridium difficile infection (CDI) from 2009 to 2013 among Veterans Healthcare Administration patientsDESIGNA retrospective descriptive analysis of data extracted from a large electronic medical record (EMR) databaseSETTINGData were acquired from VHA healthcare records from 2009 to 2013 that included outpatient clinical visits, long-term care, and hospitalized care as well as pharmacy and laboratory information.RESULTSIn 2009, there were 10,207 CDI episodes, and in 2013, there were 12,143 CDI episodes, an increase of 19.0%. The overall CDI rate increased by 8.4% from 193 episodes per 100,000 patient years in 2009 to 209 episodes per 100,000 patient years in 2013. Of the CDI episodes identified in 2009, 58% were identified during a hospitalization, and 42% were identified in an outpatient setting. In 2013, 44% of the CDI episodes were identified in an outpatient setting.CONCLUSIONThis is one of the largest studies that has utilized timely EMR data to describe the current CDI epidemiology at the VHA. Despite an aging population with greater burden of comorbidity than the general US population, our data show that VHA CDI rates stabilized between 2011 and 2013 following increases likely attributable to the introduction of the more sensitive nucleic acid amplification tests (NAATs). The findings in this report will help establish an accurate benchmark against which both current and future VA CDI prevention initiatives can be measured.Infect. Control Hosp. Epidemiol. 2015;36(9):1038–1045</jats:sec

Barkhausen Noise and Critical Scaling in the Demagnetization Curve

The demagnetization curve, or initial magnetization curve, is studied by examining the embedded Barkhausen noise using the non-equilibrium, zero temperature random-field Ising model. The demagnetization curve is found to reflect the critical point seen as the system's disorder is changed. Critical scaling is found for avalanche sizes and the size and number of spanning avalanches. The critical exponents are derived from those related to the saturation loop and subloops. Finally, the behavior in the presence of long range demagnetizing fields is discussed. Results are presented for simulations of up to one million spins.Comment: 4 pages, 4 figures, submitted to Physical Review Letter

A statistical mechanical description of metastable states and hysteresis in the 3D soft-spin random-field model at T=0

We present a formalism for computing the complexity of metastable states and the zero-temperature magnetic hysteresis loop in the soft-spin random-field model in finite dimensions. The complexity is obtained as the Legendre transform of the free-energy associated to a certain action in replica space and the hysteresis loop above the critical disorder is defined as the curve in the field-magnetization plane where the complexity vanishes; the nonequilibrium magnetization is therefore obtained without having to follow the dynamical evolution. We use approximations borrowed from condensed-matter theory and based on assumptions on the structure of the direct correlation functions (or proper vertices), such as a local approximation for the self-energies, to calculate the hysteresis loop in three dimensions, the correlation functions along the loop, and the second moment of the avalanche-size distribution.Comment: 28 pages, 12 figure

X-Ray Constraints on the Warm_hot Intergalactic Medium

Three observational constraints can be placed on a warm-hot intergalactic medium (WHIM) using \rosat PSPC pointed and survey data, the emission strength, the energy spectrum, and the fluctuation spectrum. The upper limit to the emission strength of the WHIM is 7.5 +/- 1.0 keV s^-1 cm^-2 sr^-1 keV^-1 in the 3/4 keV band, an unknown portion of which value may be due to our own Galactic halo. The spectral shape of the WHIM emission can be described as thermal emission with log T=6.42, although the true spectrum is more likely to come from a range of temperatures. The values of emission strength and spectral shape are in reasonable agreement with hydrodynamical cosmological models. The autocorrelation function in the 0.44 keV < E < 1.21 keV band range, w(theta), for the extragalactic soft X-ray background (SXRB) which includes both the WHIM and contributions due to point sources, is less than about 0.002 for 10 arcminutes < theta < 20 arcminutes in the 3/4 keV band. This value is lower than the Croft et al. (2000) cosmological model by a factor of about 5, but is still not inconsistent with cosmological models. It is also found that the normalization of the extragalactic power law component of the soft X-ray background spectrum must be 9.5 +/- 0.9 keV s^-1 cm^-2 sr^-1 keV^-1 to be consistent with the ROSAT All-Sky Survey.Comment: 5 pages, 2 figures, submitted to Astrophysical Journal Letter

Using Cerebrospinal Fluid Biomarker Testing to Target Treatment to Patients with Mild Cognitive Impairment: A Cost-Effectiveness Analysis

Objective Cerebrospinal fluid (CSF) biomarkers are shown to facilitate a risk identification of patients with mild cognitive impairment (MCI) into different risk levels of progression to Alzheimer’s disease (AD). Knowing a patient’s risk level provides an opportunity for earlier interventions, which could result in potential greater benefits. We assessed the cost effectiveness of the use of CSF biomarkers in MCI patients where the treatment decision was based on patients’ risk level. Methods We developed a state-transition model to project lifetime quality-adjusted life-years (QALYs) and costs for a cohort of 65-year-old MCI patients from a US societal perspective. We compared four test-and-treat strategies where the decision to treat was based on a patient’s risk level (low, intermediate, high) of progressing to AD with two strategies without testing, one where no patients were treated during the MCI phase and in the other all patients were treated. We performed deterministic and probabilistic sensitivity analyses to evaluate parameter uncertainty. Results Testing and treating low-risk MCI patients was the most cost-effective strategy with an incremental cost-effectiveness ratio (ICER) of US$37,700 per QALY. Our results were most sensitive to the level of treatment effectiveness for patients with mild AD and for MCI patients. Moreover, the ICERs for this strategy at the 2.5th and 97.5th percentiles were US$18,900 and US$50,100 per QALY, respectively. Conclusion Based on the best available evidence regarding the treatment effectiveness for MCI, this study suggests the potential value of performing CSF biomarker testing for early targeted treatments among MCI patients with a narrow range for the ICER

Destabilizing effects of visual environment motions simulating eye movements or head movements

In the present paper, we explore effects on the human of exposure to a visual virtual environment which has been enslaved to simulate the human user's head movements or eye movements. Specifically, we have studied the capacity of our experimental subjects to maintain stable spatial orientation in the context of moving their entire visible surroundings by using the parameters of the subjects' natural movements. Our index of the subjects' spatial orientation was the extent of involuntary sways of the body while attempting to stand still, as measured by translations and rotations of the head. We also observed, informally, their symptoms of motion sickness

Correction: Thioredoxin Glutathione Reductase from Schistosoma mansoni: An Essential Parasite Enzyme and a Key Drug Target

Correction: Thioredoxin Glutathione Reductase from Schistosoma mansoni: An Essential Parasite Enzyme and a Key Drug Targe