Assessment of institutional barriers to the use of natural gas fuel in automotive vehicle fleets

Institutional barriers to the use of natural gas as a fuel for motor vehicle fleets were identified. Recommendations for barrier removal were developed. Eight types of institutional barriers were assessed: (1) lack of a national standard for the safe design and certification of natural gas vehicles and refueling stations; (2) excessively conservative or misapplied state and local regulations, including bridge and tunnel restrictions, restrictions on types of vehicles that may be fueled by natural gas, zoning regulations that prohibit operation of refueling stations, parking restrictions, application of LPG standards to LNG vehicles, and unintentionally unsafe vehicle or refueling station requirements; (3) need for clarification of EPA's tampering enforcement policy; (4) the U.S. hydrocarbon standard; (5) uncertainty concerning state utility commission jurisdiction; (6) sale for resale prohibitions imposed by natural gas utility companies or state utility commissions; (7) uncertainty of the effects of conversions to natural gas on vehicle manufactures warranties; and (8) need for a natural gas to gasoline equivalent units conversion factor for use in calculation of state road use taxes

Optical Monitoring of Quasars: I. Variability

We present an analysis of quasar variability from data collected during a photometric monitoring of 50 objects carried out at CNPq/Laboratorio Nacional de Astrofisica, Brazil, between March 1993 and July 1996. A distinctive feature of this survey is its photometric accuracy, ~ 0.02 V mag, achieved through differential photometry with CCD detectors, what allows the detection of faint levels of variability. We find that the relative variability, delta = sigma / L, observed in the V band is anti-correlated with both luminosity and redshift, although we have no means of discovering the dominant relation, given the strong coupling between luminosity and redshift for the objects in our sample.We introduce a model for the dependence of quasar variability on frequency that is consistent with multi-wavelength observations of the nuclear variability of the Seyfert galaxy NGC 4151. We show that correcting the observed variability for this effect slightly increases the significance of the trends of variability with luminosity and redshift. Assuming that variability depends only on the luminosity, we show that the corrected variability is anti-correlated with luminosity and is in good agreement with predictions of a simple Poissonian model. The energy derived for the hypothetical pulses, ~ 10^50 erg, agrees well with those obtained in other studies. We also find that the radio-loud objects in our sample tend to be more variable than the radio-quiet ones, for all luminosities and redshifts.Comment: 17 pages, 12 figures, accepted for publication in MNRAS (uses MNRAS style

Correlated radial velocity and X-ray variations in HD 154791/4U 1700+24

We present evidence for approximately 400-d variations in the radial velocity of HD 154791 (V934 Her), the suggested optical counterpart of 4U 1700+24. The variations are correlated with the previously reported approximately 400 d variations in the X-ray flux of 4U 1700+24, which supports the association of these two objects, as well as the identification of this system as the second known X-ray binary in which a neutron star accretes from the wind of a red giant. The HD 154791 radial velocity variations can be fit with an eccentric orbit with period 404 +/- 3 d, amplitude K=0.75 +/- 0.12 km/s and eccentricity e=0.26 +/- 0.15. There are also indications of variations on longer time scales >~ 2000 d. We have re-examined all available ASM data following an unusually large X-ray outburst in 1997-98, and confirm that the 1-d averaged 2-10 keV X-ray flux from 4U 1700+24 is modulated with a period of 400 +/- 20 d. The mean profile of the persistent X-ray variations was approximately sinusoidal, with an amplitude of 0.108 +/- 0.012 ASM count/s (corresponding to 31% rms). The epoch of X-ray maximum was approximately 40 d after the time of periastron according to the eccentric orbital fit. If the 400 d oscillations from HD 154791/4U 1700+24 are due to orbital motion, then the system parameters are probably close to those of the only other neutron-star symbiotic-like binary, GX 1+4. We discuss the similarities and differences between these two systems.Comment: 6 pages, 2 figures; accepted by Ap

Model-based prediction of optogenetic sound encoding in the human cochlea by future optical cochlear implants

When hearing fails, electrical cochlear implants (eCIs) partially restore hearing by direct stimulation of spiral ganglion neurons (SGNs). As light can be better confined in space than electrical current, optical CIs (oCIs) provide more spectral information promising a fundamental improvement of hearing restoration by cochlear implants. Here, we turned to computer modelling for predicting the outcome of optogenetic hearing restoration by future oCIs in humans. We combined three-dimensional reconstruction of the human cochlea with ray-tracing simulation of emission from LED or laser-coupled waveguide emitters of the oCI. Irradiance was read out at the somata of SGNs. The irradiance values reached with waveguides were about 14 times higher than with LEDs, at the same radiant flux of the emitter. Moreover, waveguides outperformed LEDs regarding spectral selectivity. oCIs with either emitter type showed greater spectral selectivity when compared to eCI. In addition, modeling the effects of the source-to-SGN distance, orientation of the sources and impact of scar tissue further informs the development of optogenetic hearing restoration

Software for Data Acquisition AMC Module with PCI Express Interface

Free Electron Laser in Hamburg (FLASH) and XRay Free Electron Laser (XFEL) are linear accelerators that require a complex and accurate Low Level Radio Frequency (LLRF) control system. Currently working systems are based on aged Versa Module Eurocard (VME) architecture. One of the alternatives for the VME bus is the Advanced Telecommunications and Computing Architecture (ATCA) standard. The ATCA based LLRF controller mainly consists of a few ATCA carrier boards and several Advanced Mezzanine Cards (AMC). AMC modules are available in variety of functions such as: ADC, DAC, data storage, data links and even CPU cards. This paper focuses on the software that allows user to collect and plot the data from commercially available TAMC900 board

Dietary Sodium Restriction and Vascular Dysfunction with Aging

Endothelial dysfunction, commonly assessed as a decline in endothelium-dependent dilation (EDD), is a clinically important predictor of future cardiovascular diseases (CVD). EDD is reduced with age and elevated systolic blood pressure (SBP), whether assessed as brachial artery flow-mediated dilation (FMDBA) or as the forearm blood flow response to acetylcholine (FBFACh). Thus, establishing the efficacy of interventions that may preserve EDD in this population is a high biomedical research priority. Dietary sodium restriction (DSR) is one potential intervention. While the influence of sodium on BP is widely documented and appreciated, high dietary sodium has other adverse effects on cardiovascular health, independent of its effect on BP. Accordingly, the purpose of these studies was to determine a) if reduced sodium intake is associated with enhanced EDD in middle-aged and older adults (MA/O) with moderately elevated SBP; b) if DSR improves EDD in this group; and c) the physiological mechanisms mediating any improvements. In cross-sectional analyses, FMDBA was 52% higher in subjects self-reporting low sodium intake (73±6 mmol/d), without differences in endothelium-independent dilation (EID), SBP or other subject characteristics. In the entire cohort, FMDBA was inversely related to dietary sodium intake (%Δ r=-0.53, p\u3c0.01). In the intervention study, EDD was 71% (FMDBA) and 53% (peak FBFACh) higher following 4 weeks of low sodium (70±8 mmol/day) vs. normal sodium (153±7 mmol/day) intake (p\u3c0.05; randomized cross-over design), whereas EID did not change. The improvements in EDD remained significant when correcting for SBP, and other subject characteristics/dietary factors did not change. Functional improvements were mediated by increased nitric oxide (NO) bioavailability (significant reduction in FBFACh with co-infusion of an endothelial nitric oxide synthase inhibitor), increased tetrahydrobiopterin (BH4) bioavailability (FMDBA no longer improved with oral BH4) and reduced oxidative stress (FMDBA and FBFACh no longer improved with ascorbic acid infusion; reduced endothelial cell nitrotyrosine abundance). In conclusion, DSR reverses endothelial dysfunction in MA/O with moderately elevated SBP by enhancing NO and BH4 bioavailability and reducing oxidative stress. Thus, the physiological mechanisms modulating benefits of DSR are beyond BP lowering alone, and the potential impact of DSR upon CVD risk may be even greater than previously appreciated

The transcriptional transactivator Tat selectively regulates viral splicing

HIV-1 gene expression requires both viral and cellular factors to control and coordinate transcription. While the viral factor Tat is known for its transcriptional transactivator properties, we present evidence for an unexpected function of Tat in viral splicing regulation. We used a series of HIV-1 reporter minigenes to demonstrate that Tat’s role in splicing is dependent on the cellular co-transcriptional splicing activators Tat-SF1 and CA150. Surprisingly, we show that this Tat-mediated splicing function is independent from transcriptional activation. In the context of the full-length viral genome, this mechanism promotes an autoregulatory feedback that decreases expression of tat and favors expression of the env-specific mRNA. Our data demonstrate that Tat-mediated regulation of transcription and splicing can be uncoupled and suggest a mechanism for the involvement of specific transcriptional activators in splicing

Enhanced Care Assistant Training to Address the Workforce Crisis in Home Care: Changes Related to Job Satisfaction and Career Commitment

Changes in job satisfaction and career commitment were observed as a consequence of a geriatric case management training program focusing on skills development among personal care attendants in home care. A comparison of pretraining and posttraining scores uncovered a statistically signifi cant increase in Intrinsic Job Satisfaction scores for participants 18–39 years of age, whereas levels declined among the group of middle aged participants and no change was observed among participants age 52 and older. On the other hand, a statistically signifi cant decline in Extrinsic Job Satisfaction was documented over all participants, but this was found to be primarily due to declines among participants 40–51 years of age. When contacted 6–12 months after the training series had concluded, participants indicated that the training substantially increased the likelihood that they would stay in their current jobs and improved their job satisfaction to some extent. A comparison of pretraining and posttraining scores among participants providing follow-up data revealed a statistically signifi cant improvement in levels of Career Resilience. These results are discussed as they relate to similar training models and national data sets, and recommendations are offered for targeting future educational programs designed to address the long-term care workforce shortage