Investigation of frequency noise and spectrum linewidth in semiconductor optical amplifier

The characteristics of FM noise and linewidth of semiconductor optical amplifier without facet mirrors were theoretically analyzed and experimentally confirmed. The concept of discrete longitudinal mode for the spontaneous emission was introduced as the basis of quantum mechanical characteristics, allowing the quantitative examination of noise sources. The continuously broaden output spectrum profile of the amplified spontaneous emission (ASE) was well explained as a spectrum broadening of each longitudinal mode. We found that the linewidth of the inputted signal light hardly changes by the optical amplification in the SOA. The FM noise increases proportional to square value of the noise frequency and less affected by the electron density fluctuation, the linewidth enhancement factor and the ASE. The higher FM noise in the higher noise frequency is caused by the intrinsic phase fluctuation on the optical emission. The characteristics of the linewidth and the noise frequency dependency were experimentally confirmed

Shigella spp. surveillance in Indonesia: the emergence or reemergence of S. dysenteriae.

From June 1998 through November 1999, Shigella spp. were isolated in 5% of samples from 3,848 children and adults with severe diarrheal illness in hospitals throughout Indonesia. S. dysenteriae has reemerged in Bali, Kalimantan, and Batam and was detected in Jakarta after a hiatus of 15 years

Physicians' willingness to be vaccinated with a smallpox vaccine to prevent monkeypox viral infection: A cross-sectional study in Indonesia

Background Although there is no licensed vaccine for monkeypox, smallpox vaccine has been shown to be 85% effective in preventing the monkeypox. This study was conducted to assess the willingness of frontline healthcare providers to be vaccinated with smallpox vaccine to prevent monkeypox. Methods A cross-sectional study was conducted in Indonesia. The willingness was assessed under two scenarios: fully subsidized and non-subsidized vaccine. Explanatory variables such as sociodemographic profile, workplace and professional characteristics, and knowledge of monkeypox were collected. A logistic regression assessed the influence of these explanatory variables on participants’ willingness. Results Out of 510 received participants’ responses, 407 (79.8%) were analyzed. With a fully subsidized vaccine scenario, 381 (93.6%) of the participants were willing to be vaccinated and in an unadjusted analysis, gender, education, monthly income, and type of workplace were associated with willingness. With a non-subsidized vaccine (i.e. the vaccine price was US$ 17.9), the proportion who were willing to be vaccinated decreased to 71.9%. In adjusted analyses for both scenarios, gender was the only independent predictor for willingness; men were less willing to be vaccinated than women, adjusted odds ratio (aOR): 0.37; 95% confidence interval (CI): 0.16, 0.87 and aOR: 0.42; 95%CI: 0.27, 0.67, respectively for subsidized and non-subsidized scenario. Conclusion Vaccine price and gender are important factors for physicians' willingness to be vaccinated for smallpox vaccine prevent monkeypox in Indonesia. These findings indicate that achieving high vaccine converge may require partially or fully subsidized vaccines, along with a clear guideline and recommendation from authorities

Acceptance and willingness to pay for a hypothetical vaccine against monkeypox viral infection among frontline physicians: A cross-sectional study in Indonesia

Background A clinical trial is ongoing to evaluate the safety and efficacy of a monkeypox vaccine among healthcare workers (HCWs). The critical question that needs to be addressed is whether HCWs are willing to accept and purchase this vaccine. The objective of this study was to evaluate the acceptance and willingness to pay (WTP) for the vaccine among HCWs. Methods From May to July 2019, a cross-sectional study was conducted among registered general practitioners (GPs) in Indonesia. A contingent valuation method was employed to evaluate the WTP. Besides acceptance and WTP, various explanatory variables were also collected and assessed. A logistic regression and a multivariable linear regression were used to explore the explanatory variables influencing acceptance and WTP, respectively. Results Among 407 respondents, 391 (96.0) expressed acceptance of a free vaccination. The mean and median WTP was US 37.0(95CI:US 32.76�US 41.23) and US 17.90(95CI:US 17.90�US 17.90), respectively. In an unadjusted analysis, those 30 years old or younger had 2.94 times greater odds of vaccine acceptance compared to those who were older (95CI: 1.07�8.08). Location of alma mater, type of workplace, length of individual medical experience, and monthly income of GPs were all significantly associated with WTP. Conclusion Although the vast majority of GPs would accept a freely provided vaccine, they were also somewhat price sensitive. This finding indicates that partial subsidy maybe required to achieve high vaccine coverage, particularly among GPs at community health centres or those with a shorter duration of medical practice