Hormonal interactions in the control of Arabidopsis hypocotyl elongation

The Arabidopsis hypocotyl, together with hormone mutants and chemical inhibitors, was used to study the role of auxin iri cell elongation and its possible interactions with ethylene and gibberellin. When wild-type Arabidopsis seedlings were grown on media containing a range of auxin concentrations, hypocotyl growth was inhibited. However, when axr1-12 and 35S-iaaL (which have reduced auxin response and levels, respectively) were grown in the same conditions, auxin was able to promote hypocotyl growth. In contrast, auxin does not promote hypocotyl growth of axr3-1, which has phenotypes that suggest an enhanced auxin response. These results are consistent with the hypothesis that auxin levels in the wild-type hypocotyl are optimal for elongation and that additional auxin is inhibitory. When ethylene responses were reduced using either the ethylene-resistant mutant etr1 or aminoethoxyvinylglycine, an inhibitor of ethylene synthesis, auxin responses were unchanged, indicating that auxin does not inhibit hypocotyl elongation through ethylene. To test for interactions between auxin and gibberellin, auxin mutants were grown on media containing gibberellin and gibberellin mutants were grown on media containing auxin. The responses were found to be the same as wild-type Arabidopsis seedlings in all cases. In addition, 1 muM of the auxin transport inhibitor 1-naphthylphthalmic acid does not alter the response of wild-type seedlings to gibberellin. Double mutants were made between gibberellin and auxin mutants and the phenotypes of these appear additive. These results indicate that auxin and gibberellin are acting independently in hypocotyl elongation. Thus auxin, ethylene, and gibberellin each regulate hypocotyl elongation independently

The Effects of Patient Characteristics on Clinician’s Adherence to Preventive Practice Guidelines

ABSTRACT BACKGROUND: The existence of health disparities confirms that not all patients, regardless of differences in patient demographics, are provided quality healthcare (Agency of Health Care Research and Quality, 2003). Moreover, research suggests that health disparities may be present due to the inadequate delivery of medical services (S. Haist, J. Wilson, M. Lineberry, & C. Griffith, 2007; Van Ryn, Burgess, Malat, & Griffin, 2006). The differences in the delivery of care and services to ethnic minorities and those of low socioeconomic status warrant examining the role healthcare providers play in the causation of these health disparities (Smedley, Stith, & Nelson, 2003). OBJECTIVE: The purpose of the study is to identify differences in routine screening practices of Physician Assistants and determine if such differences are associated with patients’ race and socioeconomic status. DESIGN: One hundred and twelve (N = 112) practicing Physician Assistants (N = 142) in Kentucky were surveyed and randomly assigned to receive one of four clinical vignettes. The likelihood of offering different routine screening recommendations was examined based on patient race and socioeconomic status. MAIN MEASURES: We investigated the mean differences of selected preventative care recommendation options for vignette patients as a function of patient race and socioeconomic status. KEY RESULTS: A multivariate analysis revealed that the race of a patient had a statistically significant multivariate effect on differences in screening recommendation, (p =.017) for hypertension (HTN), p=.017, immunization, p=.002. Univariate analysis showed statistically significant differences, with the African American patient were significantly less likely to receive screening for hypertension (HTN), (M = 3.42), 95% CI [3.24, 3.59], or immunizations (M = 2.45), 95% CI [2.21, 2.69] when compared to Caucasian women (M = 3.71, 2.98), 95% CIs [3.55, 3.88], [2.76, 3.23], respectively. CONCULSION: The findings suggest that the race of the patient in the vignette influenced the likelihood of receiving screening recommendations. The findings show that care delivered by Physician Assistants (PAs), are a possible source of healthcare disparities between patients from racial/ethnic minority backgrounds and their Caucasian counterparts. Keywords: disparities, health education, race & ethnicity, socioeconomic, preventive car

Fabrication and verification testing of ETM 30 cm diameter ion thrusters

Engineering model designs and acceptance tests are described for the 800 and 900 series 30 cm electron bombardment thrustors. Modifications to the test console for a 1000 hr verification test were made. The 10,000 hr endurance test of the S/N 701 thruster is described, and post test analysis results are included

Specification and implementation of computer network protocols

A reliable and effective computer network can only be achieved by adopting efficient and error-free communication protocols. Therefore, the protocol designer should produce an unambiguous specification meeting these requirements. Techniques for producing protocol specifications have been the subject of intense interest over the last few years. This is partly due to the advent of an international standard for networking. A variety of methods have been employed, some of which are described in detail in this thesis. [Continues.

Auxiliary propulsion system flight package

Hughes Aircraft Company developed qualified and integrated flight, a flight test Ion Auxiliary Propulsion System (IAPS), on an Air Force technology satellite. The IAPS Flight Package consists of two identical Thruster Subsystems and a Diagnostic Subsystem. Each thruster subsystem (TSS) is comprised of an 8-cm ion Thruster-Gimbal-Beam Shield Unit (TGBSU); Power Electronics Unit; Digital Controller and Interface Unit (DCIU); and Propellant Tank, Valve and Feed Unit (PTVFU) plus the requisite cables. The Diagnostic Subsystem (DSS) includes four types of sensors for measuring the effect of the ion thrusters on the spacecraft and the surrounding plasma. Flight qualifications of IAPS, prior to installation on the spacecraft, consisted of performance, vibration and thermal-vacuum testing at the unit level, and thermal-vacuum testing at the subsystem level. Mutual compatibility between IAPS and the host spacecraft was demonstrated during a series of performance and environmental tests after the IAPS Flight Package was installed on the spacecraft. After a spacecraft acoustic test, performance of the ion thrusters was reverified by removing the TGBSUs for a thorough performance test at Hughes Research Laboratories (HRL). The TGBSUs were then reinstalled on the spacecraft. The IAPS Flight Package is ready for flight testing when Shuttle flights are resumed

The effects of velocities and lensing on moments of the Hubble diagram

We consider the dispersion on the supernova distance-redshift relation due to peculiar velocities and gravitational lensing, and the sensitivity of these effects to the amplitude of the matter power spectrum. We use the MeMo lensing likelihood developed by Quartin, Marra & Amendola (2014), which accounts for the characteristic non-Gaussian distribution caused by lensing magnification with measurements of the first four central moments of the distribution of magnitudes. We build on the MeMo likelihood by including the effects of peculiar velocities directly into the model for the moments. In order to measure the moments from sparse numbers of supernovae, we take a new approach using Kernel Density Estimation to estimate the underlying probability density function of the magnitude residuals. We also describe a bootstrap re-sampling approach to estimate the data covariance matrix. We then apply the method to the Joint Light-curve Analysis (JLA) supernova catalogue. When we impose only that the intrinsic dispersion in magnitudes is independent of redshift, we find $\sigma_8=0.44^{+0.63}_{-0.44}$ at the one standard deviation level, although we note that in tests on simulations, this model tends to overestimate the magnitude of the intrinsic dispersion, and underestimate $\sigma_8$. We note that the degeneracy between intrinsic dispersion and the effects of $\sigma_8$ is more pronounced when lensing and velocity effects are considered simultaneously, due to a cancellation of redshift dependence when both effects are included. Keeping the model of the intrinsic dispersion fixed as a Gaussian distribution of width 0.14 mag, we find $\sigma_8 = 1.07^{+0.50}_{-0.76}$.Comment: 16 pages, updated to match version accepted in MNRA

Engineering model 8-cm thruster subsystem

An Engineering Model (EM) 8 cm Ion Thruster Propulsion Subsystem was developed for operation at a thrust level 5 mN (1.1 mlb) at a specific impulse 1 sub sp = 2667 sec with a total system input power P sub in = 165 W. The system dry mass is 15 kg with a mercury-propellant-reservoir capacity of 8.75 kg permitting uninterrupted operation for about 12,500 hr. The subsystem can be started from a dormant condition in a time less than or equal to 15 min. The thruster has a design lifetime of 20,000 hr with 10,000 startup cycles. A gimbal unit is included to provide a thrust vector deflection capability of + or - 10 degrees in any direction from the zero position. The EM subsystem development program included thruster optimization, power-supply circuit optimization and flight packaging, subsystem integration, and subsystem acceptance testing including a cyclic test of the total propulsion package