783 research outputs found
Inventing Philosophy
It is often suggested that Americans do not have a culture of their own, or a philosophy of their own. However, this charge assumes a European model of culture and philosophy, which Americans need not imitate. By contrast, this paper suggests an alternative, distinctly American model of philosophy. American philosophical practice is a kind of perpetual rebirth, a continuing innocence. It amounts to starting over, always, every time, and taking nothing for granted
An Active Approach to Voting Verification
As our voting systems have come to rely more deeply on computer technology there have been great opportunities to improve the voting process, however, recently computer scientists and the general public have become wary of the amount of trust we place in the computers running our elections. Many proposals for audit systems to monitor our elections have been created. One popular audit system is the voter verified paper audit trail (VVPAT). Another more recent proposal is the voter verified audio audit transcript trail (VVAATT). In order to compare these two systems we conducted a user study where we purposely added errors to the audit trail in order to see if voters would be able to find these errors. Our results showed that voters found many more errors using the VVAATT system than they did with the VVPAT system
Quantifying the Burden and Trends of Isoniazid Resistant Tuberculosis, 1994–2009
Quantifying isoniazid resistant (INH-R) tuberculosis (TB) is important because isoniazid resistance reduces the probability of treatment success, may facilitate the spread of multidrug resistance, and may reduce the effectiveness of isoniazid preventive therapy (IPT).We used data reported to the World Health Organization between 1994-2009 to estimate the INH-R burden among new and retreatment TB cases. We assessed geographical and temporal variation in INH-R and reported levels in high HIV prevalence countries (≥2%) to understand implications for IPT. 131 settings reported INH-R data since 1994. A single global estimate of the percentage of incident TB cases with INH-R was deemed inappropriate due to particularly high levels in the Eastern European region where 44.9% (95% CI: 34.0%, 55.8%) of incident TB cases had INH-R. In all other regions combined, 13.9% (95% CI: 12.6%, 15.2%) of incident cases had INH-R with the lowest regional levels seen in West/Central Europe and Africa. Where trend data existed, we found examples of rising and falling burdens of INH-R. 40% of high HIV prevalence countries reported national data on INH-R and 7.3% (95% CI: 5.5%, 9.1%) of cases in these settings had INH-R.Outside the Eastern European region, one in seven incident TB cases has INH-R, while this rises to nearly half within Eastern Europe. Many countries cannot assess trends in INH-R and the scarcity of data from high HIV prevalence areas limits insight into the implications for IPT. Further research is required to understand reasons for the observed time trends and to determine the effects of INH-R for control of TB
Predictive power of wastewater for nowcasting infectious disease transmission: A retrospective case study of five sewershed areas in Louisville, Kentucky
Background: Epidemiological nowcasting traditionally relies on count surveillance data. The availability and quality of such count data may vary over time, limiting representation of true infections. Wastewater data correlates with traditional surveillance data and may provide additional value for nowcasting disease trends. Methods: We obtained SARS-CoV-2 case, death, wastewater, and serosurvey data for Jefferson County, Kentucky (USA), between August 2020 and March 2021, and parameterized an existing nowcasting model using combinations of these data. We assessed the predictive performance and variability at the sewershed level and compared the effects of adding or replacing wastewater data to case and death reports. Findings: Adding wastewater data minimally improved the predictive performance of nowcasts compared to a model fitted to case and death data (Weighted Interval Score (WIS) 0.208 versus 0.223), and reduced the predictive performance compared to a model fitted to deaths data (WIS 0.517 versus 0.500). Adding wastewater data to deaths data improved the nowcasts agreement to estimates from models using cases and deaths data. These findings were consistent across individual sewersheds as well as for models fit to the aggregated total data of 5 sewersheds. Retrospective reconstructions of epidemiological dynamics created using different combinations of data were in general agreement (coverage \u3e75%). Interpretation: These findings show wastewater data may be valuable for infectious disease nowcasting when clinical surveillance data are absent, such as early in a pandemic or in low-resource settings where systematic collection of epidemiologic data is difficult
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Bayesian Estimation of Mixture Models with Prespecified Elements to Compare Drug Resistance in Treatment-Naïve and Experienced Tuberculosis Cases
We propose a Bayesian approach for estimating branching tree mixture models to compare drug-resistance pathways (i.e. patterns of sequential acquisition of resistance to individual antibiotics) that are observed among Mycobacterium tuberculosis isolates collected from treatment-naïve and treatment-experienced patients. Resistant pathogens collected from treatment-naïve patients are strains for which fitness costs of resistance were not sufficient to prevent transmission, whereas those collected from treatment-experienced patients reflect both transmitted and acquired resistance, the latter of which may or may not be associated with lower transmissibility. The comparison of the resistance pathways constructed from these two groups of drug-resistant strains provides insight into which pathways preferentially lead to the development of multiple drug resistant strains that are transmissible. We apply the proposed statistical methods to data from worldwide surveillance of drug-resistant tuberculosis collected by the World Health Organization over 13 years
Bayesian Characterization of Main-Sequence Binaries in the Old Open Cluster NGC 188
The binary fractions of open and globular clusters yield powerful constraints on their dynamical state and evolutionary history. We apply publicly available Bayesian analysis tools to a UBV RIJHKS photometric catalog of the open cluster NGC 188 to detect and characterize photometric binaries along the cluster main sequence. This technique has the advantage of self-consistently handling photometric errors, missing data in various bandpasses, and star-by-star prior constraints on cluster membership. Simulations are used to verify uncertainties and quantify selection biases in our analysis, illustrating that among binaries with mass ratios \u3e0.5, we recover the binary fraction to better than 7% in the mean, with no significant dependence on binary fraction and a mild dependence on assumed mass-ratio distribution. Using our photometric catalog, we recover the majority (65% ± 11%) of spectroscopically identified main-sequence binaries, including eight of the nine with spectroscopically measured mass ratios. Accounting for incompleteness and systematics, we derive a mass-ratio distribution that rises toward lower mass ratios (within our q \u3e 0.5 analysis domain). We observe a raw binary fraction for solar-type main-sequence stars with mass ratios q \u3e 0.5 of 42% ± 4%, independent of the assumed mass-ratio distribution to within its uncertainties, consistent with literature values for old open clusters but significantly higher than the field solar-type binary fraction. We confirm that the binaries identified by our method are more concentrated than single stars, in agreement with previous studies, and we demonstrate that the binary nature of those candidates that remain unidentified spectroscopically is strongly supported by photometry from Gaia DR2
Antiviral Resistance and the Control of Pandemic Influenza
BACKGROUND: The response to the next influenza pandemic will likely include extensive use of antiviral drugs (mainly oseltamivir), combined with other transmission-reducing measures. Animal and in vitro studies suggest that some strains of influenza may become resistant to oseltamivir while maintaining infectiousness (fitness). Use of antiviral agents on the scale anticipated for the control of pandemic influenza will create an unprecedented selective pressure for the emergence and spread of these strains. Nonetheless, antiviral resistance has received little attention when evaluating these plans. METHODS AND FINDINGS: We designed and analyzed a deterministic compartmental model of the transmission of oseltamivir-sensitive and -resistant influenza infections during a pandemic. The model predicts that even if antiviral treatment or prophylaxis leads to the emergence of a transmissible resistant strain in as few as 1 in 50,000 treated persons and 1 in 500,000 prophylaxed persons, widespread use of antivirals may strongly promote the spread of resistant strains at the population level, leading to a prevalence of tens of percent by the end of a pandemic. On the other hand, even in circumstances in which a resistant strain spreads widely, the use of antivirals may significantly delay and/or reduce the total size of the pandemic. If resistant strains carry some fitness cost, then, despite widespread emergence of resistance, antivirals could slow pandemic spread by months or more, and buy time for vaccine development; this delay would be prolonged by nondrug control measures (e.g., social distancing) that reduce transmission, or use of a stockpiled suboptimal vaccine. Surprisingly, the model suggests that such nondrug control measures would increase the proportion of the epidemic caused by resistant strains. CONCLUSIONS: The benefits of antiviral drug use to control an influenza pandemic may be reduced, although not completely offset, by drug resistance in the virus. Therefore, the risk of resistance should be considered in pandemic planning and monitored closely during a pandemic
Personal digital assistants to collect tuberculosis bacteriology data in Peru reduce delays, errors, and workload, and are acceptable to users: cluster randomized controlled trial
SummaryObjectivesTo evaluate the effectiveness of a personal digital assistant (PDA)-based system for collecting tuberculosis test results and to compare this new system to the previous paper-based system. The PDA- and paper-based systems were evaluated based on processing times, frequency of errors, and number of work-hours expended by data collectors.MethodsWe conducted a cluster randomized controlled trial in 93 health establishments in Peru. Baseline data were collected for 19 months. Districts (n=4) were then randomly assigned to intervention (PDA) or control (paper) groups, and further data were collected for 6 months. Comparisons were made between intervention and control districts and within-districts before and after the introduction of the intervention.ResultsThe PDA-based system had a significant effect on processing times (p<0.001) and errors (p=0.005). In the between-districts comparison, the median processing time for cultures was reduced from 23 to 8 days and for smears was reduced from 25 to 12 days. In that comparison, the proportion of cultures with delays >90 days was reduced from 9.2% to 0.1% and the number of errors was decreased by 57.1%. The intervention reduced the work-hours necessary to process results by 70% and was preferred by all users.ConclusionsA well-designed PDA-based system to collect data from institutions over a large, resource-poor area can significantly reduce delays, errors, and person-hours spent processing data
Use of cumulative incidence of novel influenza A/H1N1 in foreign travelers to estimate lower bounds on cumulative incidence in Mexico
Background: An accurate estimate of the total number of cases and severity of illness of an emerging infectious disease is
required both to define the burden of the epidemic and to determine the severity of disease. When a novel pathogen first
appears, affected individuals with severe symptoms are more likely to be diagnosed. Accordingly, the total number of cases
will be underestimated and disease severity overestimated. This problem is manifest in the current epidemic of novel
influenza A/H1N1.
Methods and Results: We used a simple approach to leverage measures of incident influenza A/H1N1 among a relatively
small and well observed group of US, UK, Spanish and Canadian travelers who had visited Mexico to estimate the incidence
among a much larger and less well surveyed population of Mexican residents. We estimate that a minimum of 113,000 to
375,000 cases of novel influenza A/H1N1 have occurred in Mexicans during the month of April, 2009. Such an estimate
serves as a lower bound because it does not account for underreporting of cases in travelers or for nonrandom mixing
between Mexican residents and visitors, which together could increase the estimates by more than an order of magnitude.
Conclusions: We find that the number of cases in Mexican residents may exceed the number of confirmed cases by two to
three orders of magnitude. While the extent of disease spread is greater than previously appreciated, our estimate suggests
that severe disease is uncommon since the total number of cases is likely to be much larger than those of confirmed cases
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