Enhanced Understanding of Infectious Diseases by Fusing Multiple Datasets: A Case Study on Malaria in the Western Brazilian Amazon Region

BACKGROUND: A common challenge to the study of several infectious diseases consists in combining limited cross-sectional survey data, collected with a more sensitive detection method, with a more extensive (but biased) syndromic sentinel surveillance data, collected with a less sensitive method. Our article describes a novel modeling framework that overcomes this challenge, resulting in enhanced understanding of malaria in the Western Brazilian Amazon. METHODOLOGY/PRINCIPAL FINDINGS: A cohort of 486 individuals was monitored using four cross-sectional surveys, where all participants were sampled regardless of symptoms (aggressive-active case detection), resulting in 1,383 microscopy and 1,400 polymerase chain reaction tests. Data on the same individuals were also obtained from the local surveillance facility (i.e., passive and active case detection), totaling 1,694 microscopy tests. Our model accommodates these multiple pathogen and case detection methods. This model is shown to outperform logistic regression in terms of interpretability of its parameters, ability to recover the true parameter values, and predictive performance. We reveal that the main infection determinant was the extent of forest, particularly during the rainy season and in close proximity to water bodies, and participation on forest activities. We find that time residing in Acrelandia (as a proxy for past malaria exposure) decreases infection risk but surprisingly increases the likelihood of reporting symptoms once infected, possibly because non-naïve settlers are only susceptible to more virulent Plasmodium strains. We suggest that the search for asymptomatic carriers should focus on those at greater risk of being infected but lower risk of reporting symptoms once infected. CONCLUSIONS/SIGNIFICANCE: The modeling framework presented here combines cross-sectional survey data and syndromic sentinel surveillance data to shed light on several aspects of malaria that are critical for public health policy. This framework can be adapted to enhance inference on infectious diseases whenever asymptomatic carriers are important and multiple datasets are available

A Directly-Written Monolithic Waveguide-Laser Incorporating a DFB Waveguide-Bragg Grating

We report the fabrication and performance of the first C-band directly-written monolithic waveguide-laser. The waveguide-laser device was created in an Erbium and Ytterbium doped phosphate glass host and consisted of an optical waveguide that included a distributed feedback Bragg grating structure. The femtosecond laser direct-write technique was used to create both the waveguide and the waveguide-Bragg grating simultaneously and in a single processing step. The waveguide-laser was optically pumped at approximately 980 nm and lased at 1537nm with a bandwidth of less than 4 pm.Comment: 6 pages, 13 references, 4 figure

An Electron-Diffraction Investigation of Several Unsaturated Conjugated Molecules

[Summary] The electron-diffraction investigation of formaldehyde, glyoxal, dimethylgloxal, oxalyl chloride, and vinyl ether has shown that the conjugating power of two carbon-oxygen double bonds is of the same magnitude as the conjugating power of two carbon-carbon double bonds. The criterion for the magnitude of the conjugating power is the decrease in the carbon-carbon single bond distance. The carbon-carbon single bond distance in glyoxal and dimethylgloxal is 1.47Å (lg), and the carbon-carbon single bond distance in butadiene and cyclopentadiene is 1.46Å (lh). These distances are the same within the experimental error of the determination. The investigation of formaldehyde (li) gave a reliable value of the carbon-oxygen double bond distance of 1.21Å. In oxalyl chloride the carbon-carbon bond distance is only 1.50Å instead of 1.47Å as in glyoxal and dimethylgloxal (lg). The carbon-chlorine bond distance in the. same molecule is 1.72Å, a shortening of of 0.04Å. The value of 1.50Å may be explained by the competition of a free electron pair on the chlorine atom with the carbon-carbon single bond for the carbon-oxygen double bond. In vinyl ether a bond shortening of only 0.02Å in each bond or 0.04Å total shortening is reported. The shortening may be summed in this molecule as the heat of hydrogenation data(10) show that the amount of resonance in vinyl ether is the same as in ethyl vinyl ether. The shortening is due to the resonance between a tree electron pair on the oxygen atom and the two carbon-carbon double bonds. This shortening is less than that shown by the chloroethylenes(3) but the difference in electronegativity of chlorine and oxygen may well explain this fact. The molecules glyoxal, dimethylgloxal, oxalyl chloride and vinyl ether are all found to be coplanar and trans with the exception of oxalyl chloride in which the (COCl) groups are rotated 17° from the trans position. The potential barrier restricting rotation in the first three molecules was found to be greater than five kcals. and it is indicated that the potential curve for oxalyl chloride will show a double minimum. No estimate was made at the potential barrier in vinyl ether.</p

Is Earth-based scaling a valid procedure for calculating heat flows for Mars?

Heat flow is a very important parameter for constraining the thermal evolution of a planetary body. Several procedures for calculating heat flows for Mars from geophysical or geological proxies have been used, which are valid for the time when the structures used as indicators were formed. The more common procedures are based on estimates of lithospheric strength (the effective elastic thickness of the lithosphere or the depth to the brittle–ductile transition). On the other hand, several works by Kargel and co-workers have estimated martian heat flows from scaling the present-day terrestrial heat flow to Mars, but the so-obtained values are much higher than those deduced from lithospheric strength. In order to explain the discrepancy, a recent paper by Rodriguez et al. (Rodriguez, J.A.P., Kargel, J.S., Tanaka, K.L., Crown, D.A., Berman, D.C., Fairén, A.G., Baker, V.R., Furfaro, R., Candelaria, P., Sasaki, S. [2011]. Icarus 213, 150–194) criticized the heat flow calculations for ancient Mars presented by Ruiz et al. (Ruiz, J., Williams, J.-P., Dohm, J.M., Fernández, C., López, V. [2009]. Icarus 207, 631–637) and other studies calculating ancient martian heat flows from lithospheric strength estimates, and casted doubts on the validity of the results obtained by these works. Here however we demonstrate that the discrepancy is due to computational and conceptual errors made by Kargel and co-workers, and we conclude that the scaling from terrestrial heat flow values is not a valid procedure for estimating reliable heat flows for Mar

Mathematical Modeling of the Effectiveness of Facemasks in Reducing the Spread of Novel Influenza A (H1N1)

On June 11, 2009, the World Health Organization declared the outbreak of novel influenza A (H1N1) a pandemic. With limited supplies of antivirals and vaccines, countries and individuals are looking at other ways to reduce the spread of pandemic (H1N1) 2009, particularly options that are cost effective and relatively easy to implement. Recent experiences with the 2003 SARS and 2009 H1N1 epidemics have shown that people are willing to wear facemasks to protect themselves against infection; however, little research has been done to quantify the impact of using facemasks in reducing the spread of disease. We construct and analyze a mathematical model for a population in which some people wear facemasks during the pandemic and quantify impact of these masks on the spread of influenza. To estimate the parameter values used for the effectiveness of facemasks, we used available data from studies on N95 respirators and surgical facemasks. The results show that if N95 respirators are only 20% effective in reducing susceptibility and infectivity, only 10% of the population would have to wear them to reduce the number of influenza A (H1N1) cases by 20%. We can conclude from our model that, if worn properly, facemasks are an effective intervention strategy in reducing the spread of pandemic (H1N1) 2009

Diaqua­tetra­chloridotin(IV)–diglyme (1/2)

In the title 1:2 adduct, [SnCl4(H2O)2]·2C6H14O3, the SnIV atom (site symmetry 2) adopts a cis-SnO2Cl4 octa­hedral geometry. In the crystal structure, O—H⋯O hydrogen bonds lead to associations of one metal complex and two diglyme mol­ecules