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The Keck Interferometer (KI) combined the two 10 m W. M. Keck Observatory telescopes on Mauna Kea, Hawaii, as a long-baseline near- and mid-infrared interferometer. Funded by NASA, it operated from 2001 until 2012. KI used adaptive optics on the two Keck telescopes to correct the individual wavefronts, as well as active fringe tracking in all modes for path-length control, including the implementation of cophasing to provide long coherent integration times. KI implemented high sensitivity fringe-visibility measurements at H(1.6 ?m), K(2.2 ?m), and L(3.8 ?m) bands, and nulling measurements at Nband (10 ?m), which were used to address a broad range of science topics. Supporting these capabilities was an extensive interferometer infrastructure and unique instrumentation, including some additional functionality added as part of the NSF-funded ASTRA program. This paper provides an overview of the instrument architecture and some of the key design and implementation decisions, as well as a description of all of the key elements and their configuration at the end of the project. The objective is to provide a view of KI as an integrated system, and to provide adequate technical detail to assess the implementation. Included is a discussion of the operational aspects of the system, as well as of the achieved system performance. Finally, details on V2calibration in the presence of detector nonlinearities as applied in the data pipeline are provided.

To assess the association between statin therapy and risk of Alzheimer disease (AD) in a prospective cohort study with documented statin exposure and incident dementia.

Accurate information on prognosis of ALS is useful to patients, families, and clinicians.

A population-based case-control study in western Washington state was performed to assess the relation between head trauma and meningioma. Based on 200 case and 400 control subjects, head trauma was associated with an increased risk of meningioma (odds ratio 1.83; 95 CI 1.28, 2.62), especially head traumas occurring 10 to 19 years before reference date (odds ratio 4.33; 95 CI 2.06, 9.10). A dose-response relationship was present for number, but not severity, of head traumas. Whether the associations observed in this study are causal remains unclear.

A detailed assessment of intra- and inter-reader variation in the interpretation of brain SPECT scans has been performed. A random sample was selected from scans performed at a communityteaching hospital in Seattle. Scans were interpreted independently by three experienced readers who were blinded to all patient information. Forty-eight scans were interpreted twice by each reader, for a total of 288 readings. Readers recorded detailed assessments of individual lesions and overall impressions using a standardized reporting form. Intra-observer agreement as reflected in per cent agreement for severity scores ranged from 65 to 100. Intra-observer agreement on the ‘overall impression’ was very good for Alzheimer's pattern (kappa 0.73-1.00), and fair to good for the ‘heterogeneous pattern’ (kappa 0.30-0.63). Inter-observer agreement, as reflected in per cent agreement, ranged from 29 to 100. Inter-observer agreement about the ‘overall impression’ was fair to moderate for Alzheimer's pattern (kappa 0.24-0.54) and was poor for the descriptors ‘heterogeneous’ and ‘normal’. It is concluded that brain SPECT has great potential value in many important conditions. This study demonstrates a need for further work in the areas of pattern definition and reduction of observer variation.

The Neuropathology Task Force of the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) has developed a practical and standardized neuropathology protocol for the postmortem assessment of dementia and control subjects. The protocol provides neuropathologic definitions of such terms as “definite Alzheimer's disease” (AD), “probable AD,” “possible AD,” and “normal brain” to indicate levels of diagnostic certainty, reduce subjective interpretation, and assure common language. To pretest the protocol, neuropathologists from 15 participating centers entered information on autopsy brains from 142 demented patients clinically diagnosed as probable AD and on eight nondemented patients. Eighty-four percent of the dementia cases fulfilled CERAD neuropathologic criteria for definite AD. As increasingly large numbers of prospectively studied dementia and control subjects are autopsied, the CERAD neuropathology protocol will help to refine diagnostic criteria, assess overlapping pathology, and lead to a better understanding of early subclinical changes of AD and normal aging.

To examine the relationship between dietary vitamin C and hip bone mineral density (BMD) in postmenopausal women.

The Consortium to Establish a Registry for Alzheimer's Disease (CERAD) has developed brief, comprehensive, and reliable batteries of clinical and neuropsychological tests for assessment of patients with the clinical diagnosis of Alzheimer's disease (AD). We administered these batteries in a standardized manner to more than 350 subjects with a diagnosis of AD and 275 control subjects who were enrolled in a nationwide registry by a consortium of 16 university medical centers. The tests selected for this study measured the primary cognitive manifestations of AD across a range of severity of the disorder, and discriminated between normal subjects and those with mild and moderate dementia. The batteries also detected deterioration of language, memory, praxis, and general intellectual status in subjects returning for reassessment 1 year later. Interrater and testretest reliabilities were substantial. Long-term observations of this cohort are in progress in an effort to validate the clinical and neuropsychological assessments and to confirm the diagnosis by postmortem examinations. Although information on validation is limited thus far, the CERAD batteries appear to fill a need for a standardized, easily administered, and reliable instrument for evaluating persons with AD in multicenter research studies as well as in clinical practice.

To examine whether ingestion of aspartame is associated with headaches, we conducted a double-blind crossover study using volunteers with self-identified headaches after using aspartame. Of the 32 subjects randomized to receive aspartame (approximately 30 mg/kg/d) and placebo in a two-treatment, four-period crossover design, 18 completed the full protocol, seven completed part of the protocol before withdrawing due to adverse effects, three withdrew for other reasons, two were lost to follow-up, one was withdrawn due to noncompliance, and one withdrew and gave no reason. Each experimental period was 7 days long. Subjects reported headaches on 33 of the days during aspartame treatment, compared with 24 on placebo treatment (p0.04). Subjects who were “very sure” prior to the study that aspartame triggered some of their headaches reported larger treatment differences (aspartame 0.37 headache-days, placebo 0.18 headache-days; p< 0.001) than subjects who were “somewhat sure” (aspartame 0.29 headache-days, placebo 0.22 headache-days; p0.51) or "not sure" (aspartame 0.33 headache-days, placebo 0.39 headache-days; p0.51). There was no significant treatment difference in the length or intensity of headaches or in the occurrence of side effects associated with the headaches. This experiment provides evidence that, among individuals with self-reported headaches after ingestion of aspartame, a subset of this group report more headaches when tested under controlled conditions. It appears that some people are particularly susceptible to headaches caused by aspartame and may want to limit their consumption.

Reliable information on rate of progression of cognitive impairment in probable Alzheimer's disease (AD) is important for evaluating possible beneficial effects of therapeutic agents and in planning long-term care for patients with this chronic illness. However, wide variability exists in published rates of change for psychometric measures of the dementing process, and there is need for an accurate analysis of large numbers of persons with the disorder studied over long periods. Utilizing the large, well-characterized sample of the Consortium to Establish a Registry for Alzheimer's Disease and employing a least squares regression method to adjust for different levels of impairment and periods of observation, we report rates of change on the Short Blessed Test, Mini-Mental State Examination, Blessed Dementia Scale, Clinical Dementia Rating, and other cognitive measures in 430 patients with probable AD (mean age at entry 70.9 ± 8.0 SD years) studied for up to 4 years. We found that rate-of-change determinations are less reliable when the observation period is 1 year or less, that dementia progression may be nonlinear when described by certain measures, and that simple change scores do not accurately characterize the rate of decline. We also found that rate of progression in AD is determined by the severity of cognitive impairment: the less severe the dementia, the slower the rate of decline.

Preliminary animal and human data suggest that estrogens may be protective against Alzheimer's disease in women. In a population-based case-control study at Group Health Cooperative of Puget Sound, Seattle, Washington, the authors compared the exposure of estrogen replacement therapy of 107 female Alzheimer's disease cases with 120 age- and sex-matched controls by using computerized pharmacy data. The cases were obtained from the Alzheimer's Disease Patient Registry of the University of Washington, Seattle, Washington, which is based on the enumerated health plan population from 1987 to 1992. Newly recognized cases of probable Alzheimer's disease according to standardized diagnostic criteria were ascertained, evaluated, and enrolled in the Registry. The controls were selected from the same defined population by stratified random sampling. When the authors applied logistic regression, ever use of estrogens did not show an association with Alzheimer's disease (adjusted odds ratio = 1.1, 95 percent confidence interval 0.6-1.8). Oral and vaginal estrogens yielded similar results. In conclusion, this study provides no evidence that estrogen replacement therapy has an impact on the risk of Alzheimer's disease in women.

To test whether increased platelet membrane fluidity as measured by decreased steady state fluorescence anisotropy rsof diphenylhexatriene is a biologicdiagnostic marker for Alzheimer's disease AD, we enrolled 95 clinically diagnosed, probable AD cases from our Alzheimer's Disease Patient Registry and 133 control subjects of similar age and sex randomly selected from the same population base as the cases. We measured rsin platelet membranes following published assay procedures. Laboratory personnel and investigators were blind to the identity of the samples cases and controls were assayed in random order. Our analyses showed that the distributions of rsvalues were unimodal and similar for cases and controls. The overall mean differences control meancase mean for the two established assay methods tested were 0.0011 and 0.0003. A nonparametric Wilcoxon rank sum test also showed no difference between cases and controls. Multivariate analysis adjusted for the significant effects of the processing date and analysis platelet recovery led to a final model with the adjusted mean difference of 0.0007 for the principal method. Increased platelet membrane fluidity is not an antemortem diagnostic or biologic marker for AD in our population.

This case-control study investigates whether history of organic solvent exposure is associated with increased risk of Alzheimer's disease. The study base includes about 23,000 persons aged 60 years or more from the local membership of a health maintenance organization in Seattle, Washington, who entered the study between 1987 and 1992. Probable Alzheimer's disease cases (n = 193) who had presented with new dementia symptoms were identified, enrolled, and diagnosed by our Alzheimer's Disease Patient Registry following standardized criteria. Control subjects (n = 243), free of dementia and neurologic disease causing dementia, were selected randomly from the study base and frequency matched to cases for age and sex. Proxy informants provided specific solvent exposure history as well as job descriptions likely to involve solvent use as part of a comprehensive risk factor interview. Kappa statistics indicated substantial agreement for control-control proxy solvent responses. History of exposure to one or more solvent groups (benzene and toluene; phenols and alcohols; ketones; other solvents) yielded an adjusted Alzheimer's disease odds ratio of 2.3 (95 percent confidence interval 1.1-4.7); among males only, it increased to 6.0 (95% confidence interval 2.1-17.2). Thus, past exposure to organic solvents may be associated with onset of Alzheimer's disease.

The statistical problem of spurious correlation occurs when ratio variables with the same denominator are correlated. The correlation between two variables is also altered when heterogeneous groups are pooled. The problem is illustrated in the assessment of steady-state plasma levels of carbamazepine (CBZ), CBZ-10, 11-epoxide (CBZ-epoxide), and 10, 11-dihydro-10, 11-trans-dihydroxy-CBZ (CBZ-diol) in 12 epileptic patients on CBZ monotherapy and 12 epileptic patients on CBZ polytherapy. Expressing outcomes as dose/level ratios and metabolite level/parent drug level ratios is shown to be inappropriate, leading to spurious correlation. The amount of spurious correlation induced can be assessed by use of available statistical methodology, as is illustrated in this paper. More appropriate, alternative approaches are illustrated, using the data on the 24 patients with epilepsy.

We investigated whether cigarette smoking is negatively associated with Alzheimer's disease (AD) in a population-based, frequency-matched, case-control study of 152 AD patients and 180 controls. Ever having smoked was associated with lower risk of AD (adjusted odds ratio 0.61; 95 confidence interval: 0.37–0.99). Additional multivariate analyses demonstrated that education and history of hypertension modified this association. The direction of the modification was for higher education level and history of hypertension to further reduce the risk. The “dose response” pattern showed the greatest risk reduction among those who smoked least and suggests a biologic mechanism of a dose-dependent up-regulation of nicotinic (cholinergic) brain receptors. These data, although consistent with current opinion about pathophysiology of AD, do not suggest smoking should be used as a preventive strategy for AD.

The relation between head trauma and Alzheimer's disease was one of four major risk factors explored in a case-control study of 130 matched pairs; cases were clinically diagnosed between January 1980 and June 1985 at two geriatric psychiatric clinics in Seattle, Washington, and controls were friends or nonblood relatives of the cases. Subjects were matched by age, sex, and relationship between the case and his or her surrogate respondent. Head injuries which resulted in a loss of consciousness or which caused the subject to seek medical care were documented by means of interviews with surrogate respondents. A history of head injury was recorded for 24% of the cases and 8.5% of the controls, yielding an odds ratio of 3.5 (95% confidence interval 1.5-8.3) in conditional logistic regression analysis adjusted for age at onset of disease symptoms and family history of Alzheimer's disease. The estimated risk of Alzheimer's disease increased as the time between the last head trauma event and the onset of disease symptoms diminished (p = 0.002). This trend remained statistically significant (p = 0.006) when head injuries which occurred within 5 years of onset of the disease were excluded from the analysis. There was some difference between cases and controls for the average duration of unconsciousness in events accompanied by such a loss, but this was not statistically significant. The two groups were also similar in the circumstances surrounding the injuries and in the frequency of alcohol problems. This is the third case-control study to find a statistically significant association between head trauma and Alzheimer's disease.

Group B streptococci (GBS) are the most common cause of pneumonia and sepsis during the neonatal period; however, the pathogenesis of this infection is poorly understood. We investigated the ability of GBS to enter epithelial cells in culture. Two strains of GBS were capable of invading immortalized respiratory epithelial cell lines in vitro at different levels, suggesting strain differences in invasiveness. Intracellular replication was not observed. Invasion required actin microfilaments but not microtubular cytoskeletal elements. Active bacterial protein, DNA, and RNA syntheses were required for invasion. These findings are consistent with our previous observation of intracellular GBS in the lungs of infected primates. We hypothesize that this organism may access the bloodstream by direct invasion of the epithelial cell barrier.

All 1998 resident infant deaths in the 1969--1977 King County, Washington birth cohort of 139,132 resident live births comprise the data base for epidemiologic comparisons of the sudden infant death syndrome (SIDS) with eight other major infant mortality components: hyaline membrane disease; respiratory distress syndrome; asphyxia of the newborn; immaturity; birth injury; congenital malformation; infection; and "all other." These components were compared with respect to age at death; sex; race; prior fetal loss; prior live-born, now dead; birth plurality; birth weight; maternal age; birth order; marital status; prenatal care; and season of death in an attempt to determine the uniqueness of these purported SIDS risk factors. Only the age at death distribution unequivocally distinguished SIDS from the other components. The combination of low maternal age and multiparity was demonstrated to be putatively synergistic for risk of SIDS, hyaline membrane disease, and respiratory disease syndrome. Only deaths from infection exhibited seasonal variation similar to SIDS. These observations probably reflect secondary associations with as yet unidentified primary risk factors relatable to maternal experience.

We introduce an observational tool based on visibility nulls in optical spectro-interferometry fringe data to probe the structure of stellar atmospheres. In a preliminary demonstration, we use both Navy Precision Optical Interferometer (NPOI) data and stellar atmosphere models to show that this tool can be used, for example, to investigate limb darkening.Using bootstrapping with either multiple linked baselines or multiple wavelengths in optical and infrared spectro-interferometric observations of stars makes it possible to measure the spatial frequency u0at which the real part of the fringe visibility Re(V)vanishes. That spatial frequency is determined by u0=B⊥/λ0, where B⊥is the projected baseline length, and λ0is the wavelength at which the null is observed. Since B⊥changes with the Earth’s rotation, λ0also changes. If u0is constant with wavelength, λ0varies in direct proportion to B⊥. Any departure from that proportionality indicates that the brightness distribution across the stellar disk varies with wavelength via variations in limb darkening, in the angular size of the disk, or both.In this paper, we introduce the use of variations of u0with λas a means of probing the structure of stellar atmospheres. Using the equivalent uniform disk diameter θUD,0(λ0), given by θUD,0=1.22/u0(λ0), as a convenient and intuitive parameterization of u0(λ0), we demonstrate this concept by using model atmospheres to calculate the brightness distribution for νOphiuchi and to predict θUD,0(λ0), and then comparing the predictions to coherently averaged data from observations taken with the NPOI.

In a population-based case-control study of 200 cases and 400 controls in western Washington State, the authors assessed associations between meningioma and ionizing radiation in medical and occupational settings. No significant associations were observed for diagnostic studies or occupational settings, but associations were observed for radiation therapy to head or neck (odds ratio 3.7, 95% CI 1.5 to 9.5), especially for neoplastic conditions. Only four patients (2%) had meningiomas that followed high-dose cranial radiation.

Serum prolactin levels rise after generalized tonic-clonic and partial complex seizures, but not after pseudoepileptic seizures. The criteria for a significant elevation in serum prolactin vary with individual investigators. The prevalence of pseudoseizures in the population studied determines the predictive value of serum prolactin determinations. In populations where most patients have epilepsy, a rise in serum prolactin is highly predictive for true epilepsy, but no increase in serum prolactin is not predictive for pseudoseizures.

The authors report the input referred low-frequency noise (2 – 100 kHz) spectra of 0.2 µm-gate-length GaAs MESFETs which were gate-recess-etched using a selective Freon 12 based dry-etching process. For comparison, the noise spectra of nonselective wet-chemical, ammonia-based gate-recess-etched devices are also presented. Little change in low-frequency noise performance is observed for devices dry-etched for 30 – 50 s, demonstrating the latitude of the dry-etch process. Additionally, the input referred noise of the wet-etched devices was greater than that of 30, 40 and 50 s dry-etched devices, suggesting that the dry-etching process may passivate traps contributing to the low-frequency noise component of the MESFETs.

Context.Giant stars, and especially C-rich giants, contribute significantly to the chemical enrichment of galaxies. The determination of precise parameters for these stars is a necessary prerequisite for a proper implementation of this evolutionary phase in the models of galaxies. Infrared interferometry opened new horizons in the study of the stellar parameters of giant stars, and provided new important constraints for the atmospheric and evolutionary models.

To investigate the association of early-life factors with AD.