Continuous optical generation of microwave signals for fountain clocks.

For the optical generation of ultrastable microwave signals for fountain clocks, we developed a setup based on a cavity stabilized laser and a commercial frequency comb. The robust system, in operation since 2020, is locked to a 100 MHz output frequency of a hydrogen maser and provides an ultrastable 9.6 GHz signal for the interrogation of atoms in two cesium fountain clocks, acting as primary frequency standards. Measurements reveal that the system provides a phase noise level that enables quantum projection noise limited fountain frequency instabilities at the low 10-14(τ/s)-1/2 level. At the same time, it offers largely maintenance-free operation.

Phase Analysis for Frequency Standards in the Microwave and Optical Domains.

Coherent manipulation of atomic states is a key concept in high-precision spectroscopy and used in atomic fountain clocks and a number of optical frequency standards. Operation of these standards can involve a number of cyclic switching processes, which may induce cycle-synchronous phase excursions of the interrogation signal and thus lead to shifts in the output of the frequency standard. We have built a field-programmable gate array (FPGA)-based phase analyzer to investigate these effects and conducted measurements on two kinds of frequency standards. For the caesium fountains PTB-CSF1 and PTB-CSF2, we were able to exclude phase variations of the microwave source at the level of a few microradians, corresponding to relative frequency shifts of less than [Formula: see text]. In the optical domain, we investigated phase variations in PTB's Yb (+) optical frequency standard and made detailed measurements of acousto-optic modulator (AOM) chirps and their scaling with duty cycle and driving power. We ascertained that cycle-synchronous as well as long-term phase excursion do not cause frequency shifts larger than [Formula: see text].

Methodological complexities and the use of GIS in conducting a community needs assessment of a large U.S. municipality.

Reliable assessment of health and social needs within a community ensures that local input drives strategic planning and programmatic decisions. Results are used to determine the priorities and focus of local public health departments and to support the activities of health and social service agencies. We utilized a geographic information system in the planning, administration, and analysis of a recent community needs assessment to ensure a reliable and randomly distributed sample of a diverse urban population and to allow for small geographic area analysis of disease prevalence data. Collection of location data at the time of the 3,361 face-to-face assessment interviews allowed for the association of spatial data with measures of health conditions and behaviors. Results of the assessment indicated a need for public health programs designed to address emerging public health concerns in the community. Incorporating a spatial component in analyses of morbidity and needs assessment data allows for efficient integration of demographic and socio-economic census data and permits ad hoc analyses of varied and changing geographic strata.

Assessment of physician preparedness and response capacity to bioterrorism or other public health emergency events in a major metropolitan area.

BACKGROUND: The role of physicians in the detection, reporting, and response to infectious disease outbreaks, anomalous biologic events, or other public health emergencies is critical to the community's safety. OBJECTIVE/METHOD: In an effort to assess the level of preparedness of local physicians to respond to such events, the City of Fort Worth Public Health Department, the Fort Worth/Tarrant County Health Authority, and the Tarrant County Medical Society collaborated in designing and administering a cross-sectional study in spring 2006. RESULTS: The results serve as a baseline of the local clinical community's preparedness, with 91% of local physicians reporting their knowledge as "fair-poor," 80% desiring more information, and 83% favoring more training opportunities. CONCLUSION: Information obtained through this assessment is used to help cultivate educational interventions that will enhance the participation, integration, and mobilization of clinicians in the event of a community emergency.

Lay beliefs about high blood pressure in a low- to middle-income urban African-American community: an opportunity for improving hypertension control.

PURPOSE: Lay beliefs about illness are a potential barrier to improving the control of hypertension. We investigated the extent to which lay beliefs about hypertension diverge from current medical understanding. METHODS: We conducted street intercept interviews and focus group discussions in six predominantly African-American census tracts in the southern sector of Dallas County, Texas. Sixty subjects, aged 18 to 67 years, were stopped along popular thoroughfares and administered a brief survey. Additionally, 107 participants were interviewed in 12 homogeneous focus groups, balanced by sex and age (18 to 74 years). Participants were asked about the meaning, causes, consequences, and treatment of high blood pressure. RESULTS: The street intercept data indicated that 35% (n = 21) of respondents related high blood pressure to eating pork or other foods that makes the blood travel too fast to the head, and only 15% (n = 9) related hypertension to an elevated pressure in blood vessels. The focus group data indicated that hypertension was causally linked to eating pork in 8 of the 12 groups; was perceived as a symptomatic illness in all 12 groups; and was considered treatable with vitamins, garlic, and other herbs in 11 groups, with prescription medications in 10 groups and with lifestyle modifications such as weight loss in 8 groups. Hypertension was mentioned as a leading cause of death among African Americans in none of the 4 focus groups of 18-year-old to 29-year-old participants, in 2 of the 4 focus groups of 30-year-old to 49-year-old participants, and in 3 of the 4 focus groups of 50-year-old to 74-year-old participants. CONCLUSIONS: In a low- to middle-income urban African-American community, the predominant beliefs about hypertension diverged sharply from current medical understanding. Lack of appreciation of these lay beliefs by providers may contribute to noncompliance and poor rates of hypertension control.