Random lasing from optical fibers with phase separated glass cores.

A novel random laser, integrating a passive optical fiber with a phase separated aluminosilicate core-silica cladding as the feedback medium, is proposed and presented. The core exhibits greatly enhanced Rayleigh scattering, therefore requiring a significantly reduced length of scattering fiber (4 m) for lasing. With a Yb-doped fiber as the gain medium, the fiber laser operates at 1050 nm with low threshold power and possesses an output that can be amplified through conventional means. Furthermore, the laser was found to have a high degree of spatial coherence, spectral broadening with increasing input power, and temporal spectral variation. The facile setup and results herein pave the way for further study and applications based on low threshold random fiber lasers.

Highly nonlinear yttrium-aluminosilicate optical fiber with a high intrinsic stimulated Brillouin scattering threshold.

Highly nonlinear (high-NA small-mode-area) optical fibers also possessing an intrinsically high stimulated Brillouin scattering threshold are described. More specifically, silica clad, yttrium-aluminosilicate core fibers are shown to exhibit an intrinsically low Brillouin gain coefficient between 0.125 and 0.139×10-11 m/W and a Brillouin gain linewidth of up to 500 MHz. Losses on the order of 0.7 dB/m were measured, resulting from impurities in the precursor materials. Nonlinear refractive index values are determined to be similar to that of silica, but significant measurement uncertainty is attributed to the need to estimate dispersion curves since their direct measurement could not be made. The interest for highly nonlinear optical fibers with a low intrinsic Brillouin gain coefficient is expected to continue, especially with the growing developments of narrow-linewidth high-energy laser systems.

Single- and few-moded lithium aluminosilicate optical fiber for athermal Brillouin strain sensing.

Results are presented toward realizing a true single-mode fiber whose Brillouin frequency shift is independent of temperature, while its dependence on strain is comparable to conventional high-silica-content single-mode fibers. Demonstrated here is a fiber with a negative thermal sensitivity dν/dT of -0.26 MHz/K and a strain sensitivity of +406 MHz/%. The suppression of the Brillouin thermal response is enabled by the large thermal expansion coefficient of the group I oxide-containing silica glass network.

Building a gateway to promote cardiovascular health research in African-American communities: lessons and findings from the field.

African American communities traditionally mistrust academic research. This forms a significant barrier to understanding cardiovascular risk factors in this population, which bears an excess risk of cardiovascular disease and stroke. A clergy/academic partnership was established to build a gateway for salient research and for improving resources for reducing cardiovascular disease risk in the community. From this partnership emanated the African American Family Heart Study. People with a family history of premature coronary heart disease (CHD) have an increased risk for the disease--as high as 12 times that of the general population, if among siblings. Considerably less is known about the actual remediable risk factors in African American families with premature CHD. We initiated the Family Heart Study with a full characterization of 161 apparently healthy, unaffected 30- to 59-year-old African Americans whose siblings were 85 African American index cases with documented premature CHD prior to 60 years of age. We compared their risk factor values to population reference norms obtained in the Third National Health and Nutrition Examination Survey (NHANES III) and the National Health Interview Survey (NHIS) for cigarette smoking. Only 13% of African American male siblings and 14% of female siblings from these families were without any major remediable risk factors. The fact that so many siblings were at extremely high risk calls into question the current applications by provider systems of national guidelines in high-risk African American families. This is an easily identifiable population that would be likely to benefit greatly from targeted screening and culturally sensitive and appropriate treatment.

Building a gateway to promote cardiovascular health research in African American communities: lessons and findings from the field.

African American communities traditionally mistrust academic research. This forms a significant barrier to understanding cardiovascular risk factors in this population, which bears an excess risk of cardiovascular disease and stroke. A clergy/academic partnership was established to build a gateway for salient research and for improving resources for reducing cardiovascular disease risk in the community. From this partnership emanated the African American Family Heart Study. People with a family history of premature coronary heart disease (CHD) have an increased risk for the disease--as high as 12 times that of the general population, if among siblings. Considerably less is known about the actual remediable risk factors in African American families with premature CHD. We initiated the Family Heart Study with a full characterization of 161 apparently healthy, unaffected 30- to 59-year-old African Americans whose siblings were 85 African American index cases with documented premature CHD prior to 60 years of age. We compared their risk factor values to population reference norms obtained in the Third National Health and Nutrition Examination Survey (NHANES III) and the National Health Interview Survey (NHIS) for cigarette smoking. Only 13% of African American male siblings and 14% of female siblings from these families were without any major remediable risk factors. The fact that so many siblings were at extremely high risk calls into question the current applications by provider systems of national guidelines in high-risk African American families. This is an easily identifiable population that would be likely to benefit greatly from targeted screening and culturally sensitive and appropriate treatment.

A partnership with minority populations: a community model of effectiveness research.

This paper describes a community-based approach, including a partnership of an academic medical institution and a high-risk, urban, African-American population, directed at decreasing premature morbidity and mortality and enhancing health and functional status. The intervention approach is based on a model of community-based leadership and "ownership" of interventions and programs to enhance sustainability of effective approaches, and it follows specific stages to assure appropriate assessment and evaluation. Initial efforts were directed at the control of hypertension and were coordinated through decentralized mayor's stations in Baltimore, Maryland. This approach was successful in significantly enhancing control of hypertension and reducing related morbidity and mortality. Over time, an enhanced partnership has been coordinated through churches in the community and organized around a program entitled "Heart, Body, and Soul." Current efforts are directed at the major risk factors and preventable and/or controllable problems in the population, such as hypertension, smoking, obesity, diabetes, hyperlipidemia, and cervical and breast cancer. Key components include the training of neighborhood health workers to provide screening, counseling, monitoring, support, and follow-up; enhanced access to care; training of high school students as health counselors; and use of media to promote healthier life-styles.

Patients' responses to short obstetrical hospital stays during a nurses' strike.

A 1984 St. Paul nurses' strike led to a reduction in the length of obstetrical hospital stays, and this effect persisted after the strike. The mean length of hospitalization for vaginal deliveries was 2.7 days before the strike, 1.6 days during the strike, and 2.4 days after the strike. Forty-nine women who delivered during the strike completed questionnaires investigating their attitudes about their length of hospital stay. Although the mean patient response to length of stay was slightly positive, several patients were dissatisfied with their short hospital stays. Patients who stayed for two days or longer were more positive about their length of stay than those who stayed for shorter periods of time. It was planned that most women with vaginal deliveries would be discharged within 24 hours; however, 11 of the 36 women with vaginal deliveries stayed two days or more. This study demonstrates the need to individualize discharge plans. Not all women with vaginal deliveries can be discharged within 24 hours, and one may expect some patient dissatisfaction when early discharge is mandated.