Biomedical subjects

R E Miles

Publications and source records attributed to R E Miles.

12 recordsLinked to original sources

PubMed2005

The analysis of human cortical bone by terahertz time-domain spectroscopy.

Samples of cortical bone, derived from human femur, have been studied using terahertz time-domain transmission spectroscopy. The relationship between the broadband THz parameters and the previously acquired values of Young's modulus and x-ray attenuation (CT number), and the density of each bone sample, is investigated. The only significant correlation is that between THz transmission and sample density, suggesting that the potential use of THz radiation as a non-invasive probe of bone quality is limited. The spectra of absorption coefficient and refractive index are plotted over the frequency range 0.1-1.25 THz. There is evidence that the sample hydration state is a factor in the resultant THz parameters.

Bone Density↗

PubMed2002

Evaluation of image quality in terahertz pulsed imaging using test objects.

As with other imaging modalities, the performance of terahertz (THz) imaging systems is limited by factors of spatial resolution, contrast and noise. The purpose of this paper is to introduce test objects and image analysis methods to evaluate and compare THz image quality in a quantitative and objective way, so that alternative terahertz imaging system configurations and acquisition techniques can be compared, and the range of image parameters can be assessed. Two test objects were designed and manufactured, one to determine the modulation transfer functions (MTF) and the other to derive image signal to noise ratio (SNR) at a range of contrasts. As expected the higher THz frequencies had larger MTFs, and better spatial resolution as determined by the spatial frequency at which the MTF dropped below the 20% threshold. Image SNR was compared for time domain and frequency domain image parameters and time delay based images consistently demonstrated higher SNR than intensity based parameters such as relative transmittance because the latter are more strongly affected by the sources of noise in the THz system such as laser fluctuations and detector shot noise.

Diagnostic Imaging↗

PubMed1996

Occupational outcome in military aviators after psychiatric hospitalization.

OBJECTIVE: To determine if psychiatric hospitalization precluded a return to occupational status in United States Air Force aviators. DESIGN: A 7-yr retrospective review that joined hospitalization and occupational databases using individual identifiers. SUBJECTS: From a population of over 35,000 USAF rated aviation officers present between January 1986 and December 1990, 214 were both psychiatrically hospitalized and on flying status the quarter prior. PRIMARY OUTCOME MEASURE: Return to flying duties during a minimum follow-up period of 2 yr. RESULTS: Within 2 yr from psychiatric admission, 138 (64.5%) aviators returned to flying status; 141 (65.9%) returned over 7 yr. In this patient population, an affective disorder diagnosis predicted poor outcome (chi 2 = 12.86; df = 1; p = 0.0003), independent of length of hospitalization. CONCLUSION: Psychiatric hospitalization did not prevent a return to flying status for a majority of these high functioning aviators. Although an affective disorder diagnosis negatively affected occupational outcome, it is unclear whether institutional policy or poor prognosis was etiologic.

Adjustment Disorders↗

PubMed1994

Viral hepatitis in the U.S. Air Force, 1980-89: an epidemiological and serological study.

This paper reports the epidemiology of hospital-diagnosed acute viral hepatitis in U.S. Air Force personnel from 1980-89. First hospitalizations for viral hepatitis generally declined, ranging from 24.6 to 47.2 per 100,000 personnel. Hepatitis rates were higher among men, (RR = 1.3; 95% C.I., 1.1-1.5) and higher among blacks, compared to whites (RR = 1.4; 95% C.I., 1.3-1.6). Analysis of risk associated with various occupations demonstrated an increased risk of viral hepatitis for procedurally oriented medical personnel (physicians, clinical nurses, dentists) when compared to all other occupations (RR = 1.5; 95% C.I., 1.1-1.9). Pilots and navigators demonstrated a decreased risk of acute viral hepatitis. Members hospitalized for hepatitis B had a prior or concurrent diagnosis for sexually transmitted disease in 37% of cases; for drug abuse, 32% of cases. Serum samples from 332 individuals demonstrated that hepatitis A had the highest rate of agreement (84%) between serology and hospital discharge diagnosis. Only 3% of individuals with the diagnosis of NANB hepatitis were positive for hepatitis C.

Adolescent↗

PubMed1981

Life events stress, subjective appraisal and somatization in hypertension: a pilot study.

The present pilot study was designed as a multivariate test of stress as a factor in hypertension. A model is proposed that includes family history of hypertension, high life stress exposure, the subjective appraisal of being under considerable stress, and the tendency to somatize stress cardiovascularly. Health risk behaviors frequently implicated in hypertensive disease were also measured. A sample of 76 low income black adults were interviewed privately and classified into two groups on the basis of "no elevated blood pressure readings" or "1 + elevated readings." Univariate comparisons generally supported the hypotheses. Multivariate stepwise discriminant analyses also were conducted as a stricter test of the model. Six factors were identified as the major discriminators between the groups: cardiovascular and renal symptoms, family history of high blood pressure, proportion of negative to total life change events, and electrodermal and gastrointestinal somatic reactions. Age and positive life stress experiences were also important discriminators.

Adult↗

PubMed1979

Miles's six other maxims of management.

Rufus Miles has suggested that where you stand depends on where you sit. But the converse may also be true with regard to your acceptance of his six other maxims: Where you sit may depend on where you stand--that is, on whether you accept the truth of these maxims.

Administrative Personnel↗

PubMed1978

Organizational strategy, structure, and process.

Organizational adaptation is a topic that has received only limited and fragmented theoretical treatment. Any attempt to examine organizational adaptation is difficult, since the process is highly complex and changeable. The proposed theoretical framework deals with alternative ways in which organizations define their product-market domains (strategy) and construct mechanisms (structures and processes) to pursue these strategies. The framework is based on interpretation of existing literature and continuing studies in four industries (college textbook publishing, electronics, food processing, and health care).

Goals↗

PubMed1978