Predictions of the emergence of vaccine-resistant hepatitis B in The Gambia using a mathematical model

Vaccine escape variants of hepatitis B virus (HBV) have been identified world-wide. A mathematical model of HBV transmission is used to investigate the potential pattern of emergence of such variants. Attention is focused on The Gambia as a country with high quality epidemiological data, universal infant immunization and in which escape mutants after childhood infections have been observed. We predict that a variant cannot become dominant for at least 20 years from the start of vaccination, even when using a vaccine which affords no cross protection. The dominant factor responsible for this long time scale is the low rate of infectious contacts between infected and susceptible individuals (we estimate the basic reproduction number of hepatitis B in The Gambia to be 1·7). A variant strain that achieves high prevalence will also take many years to control, and it is questionable whether emergence will be identifiable by sero-surveillance until of high prevalence. The sensitivity of the model predictions to epidemiological and demographic factors is explored

Predictions of the emergence of vaccine-resistant hepatitis B in The Gambia using a mathematical model

Vaccine escape variants of hepatitis B virus (HBV) have been identified world-wide. A mathematical model of HBV transmission is used to investigate the potential pattern of emergence of such variants. Attention is focused on The Gambia as a country with high quality epidemiological data, universal infant immunization and in which escape mutants after childhood infections have been observed. We predict that a variant cannot become dominant for at least 20 years from the start of vaccination, even when using a vaccine which affords no cross protection. The dominant factor responsible for this long time scale is the low rate of infectious contacts between infected and susceptible individuals (we estimate the basic reproduction number of hepatitis B in The Gambia to be 1·7). A variant strain that achieves high prevalence will also take many years to control, and it is questionable whether emergence will be identifiable by sero-surveillance until of high prevalence. The sensitivity of the model predictions to epidemiological and demographic factors is explored

Drivers of distribution trends and success: Consumers, technology, competition, EU

Hungary's domestic markets and export markets are growing. Entry into a unified European market is rapidly approaching. What are the things in the area of distribution to which Hungarian firms should be paying attention to enable them to prosper in these growing markets? This presentation will discuss: infrastructure drivers; consumer drivers; technology drivers including paperless systems for ordering, payment, and shipping; European integration; electronic commerce; structural changes, organization and competition in vertical distribution systems

Perception Visualization: Seeing Through the Eyes of a DNN

Artificial intelligence (AI) systems power the world we live in. Deep neural networks (DNNs) are able to solve tasks in an ever-expanding landscape of scenarios, but our eagerness to apply these powerful models leads us to focus on their performance and deprioritises our ability to understand them. Current research in the field of explainable AI tries to bridge this gap by developing various perturbation or gradient-based explanation techniques. For images, these techniques fail to fully capture and convey the semantic information needed to elucidate why the model makes the predictions it does. In this work, we develop a new form of explanation that is radically different in nature from current explanation methods, such as Grad-CAM. Perception visualization provides a visual representation of what the DNN perceives in the input image by depicting what visual patterns the latent representation corresponds to. Visualizations are obtained through a reconstruction model that inverts the encoded features, such that the parameters and predictions of the original models are not modified. Results of our user study demonstrate that humans can better understand and predict the system's decisions when perception visualizations are available, thus easing the debugging and deployment of deep models as trusted systems.Comment: Accepted paper at BMVC 2021 (Proceedings not available yet

Consequences of Thymidine Catabolism for Estimates of Bacterial Production: An Example from a Coastal Marine Sediment

Radioactively labeled thymidine (TdR) has been used extensively to measure bacterial production in aquatic environments, but critical assumptions of the TdR technique often have gone untested. In this study of a coastal marine sediment, the metabolic fate of methyl [3H]TdR and methyl [14C]TdR was at variance with the assumptions necessary for determining bacterial production. Only 2% of incorporated radioactivity was recovered in the DNA fraction of TCA-insoluble material following time-course incubations of l-300 min. At least the methyl group of TdR was extensively catabolized, as shown by copious production of 14C02. The temporal patterns of 3H : 14C ratios in macromolecular fractions indicated that products of catabolism were recycled into the DNA fraction. The accuracy of the TdR technique depends in large part on the degree to which such catabolism occurs

An initial assessment of native and invasive tunicates in shellfish aquaculture of the North American east coast

Author Posting. © The Author(s), 2010. This is the author's version of the work. It is posted here by permission of John Wiley & Sons for personal use, not for redistribution. The definitive version was published in Journal of Applied Ichthyology 26, Supple.s2 (2010): 8-11, doi:10.1111/j.1439-0426.2010.01495.x.The objective of the study was to assess the distribution of native and invasive tunicates in the fouling community of shellfish aquaculture gear along the U.S. east coast of the Atlantic. Since the 1980s, several species of invasive tunicates have spread throughout the coastal waters of the North American east coast and have become dominant fouling organisms on docks, boat hulls, mooring lines, and in shellfish aquaculture. Invasive and native tunicates negatively impact shellfish aquaculture through increased maintenance costs and reduced shellfish growth. While the presence of alien tunicates has been well documented at piers, harbors, and marinas, there are few published reports of invasive tunicate impacts to aquaculture. We surveyed shellfish aquaculture operations at Martha’s Vineyard, Massachusetts and shellfish aquaculturists in other areas along the North American east coast and report high levels of fouling caused by seven invasive, three native, and two cryptogenic species of tunicates. All study sites were fouled by one or more tunicate species. Biofouling control treatments varied among aquaculture sites and were effective in removing tunicates. Invasive and native tunicates should be considered when assessing the economic impacts of fouling organisms to the aquaculture industry.This work was funded in part by Sailors’ Snug Harbor of Boston, the Adelaide and Charles Link Foundation, and the NOAA Aquatic Invasive Species Program

NovaSAR and SSTL S1-4: SAR and EO Data Fusion

The NovaSAR and SSTL S1-4 satellites were launched into a 580 km sun-synchronous orbit on 16th September 2018. NovaSAR is an S-band Synthetic Aperture Radar (SAR) platform, and SSTL S1-4 hosts a multi-spectral (RGB, NIR) and panchromatic electro-optical (EO) high-resolution payload1. As the satellites are adjacent in orbit, with NovaSAR leading SSTL S1-4 by ~15 minutes, this provides an opportunity to demonstrate the benefits of using SAR and EO data together. The key demonstration principles are: to show the complementary nature of near-contemporaneous SAR and EO data, tipping and cueing opportunities of a tandem sensor, and to demonstrate the superiority of one technology for a specific application. The ability to undertake enhanced vessel detection using machine learning algorithms, to use bathymetry with EO and SAR imagery to get a more complete picture, and to detect oil spills in SAR imagery have been demonstrated. This proves the capability of the technologies, and their strengths as joint and separate data sources, helping to inform future mission concepts

Ascidians at the Pacific and Atlantic entrances to the Panama Canal

© The Author(s), 2011. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Aquatic Invasions 6 (2011): 371-380, doi:10.3391/ai.2011.6.4.02.The Panama Canal region is susceptible to non-native species introductions due to the heavy international shipping traffic through the area. Ascidian introductions are occurring worldwide but little is known about introductions at the Panama Canal. Surveys were conducted in 2002, 2008, and 2009 within the Pacific and Atlantic entrances to the canal. We found a high diversity of ascidians on both sides of the canal, dominated by non-native species; six species occurred at both Pacific and Atlantic Panama sites. This is the first report of Polyandrocarpa anguinea and P. sagamiensis in Atlantic Panama waters and Ascidia incrassata, Ascidia sydneiensis, Botrylloides nigrum, Botryllus planus, Didemnum perlucidum, Diplosoma listerianum, Microcosmus exasperatus, Polyandrocarpa zorritensis, Polyclinum constellatum, Symplegma brakenhielmi, Symplegma rubra, and Trididemnum orbiculatum in Pacific Panama waters. The canal may serve as a major invasion corridor for ascidians and should be monitored over time.Funding for this project came from WHOI Ocean Life Institute-Tropical Research Initiative to Carman and CNPq to Rocha

Health practices, risk factors, and chronic disease in Tecumseh

Seven health practices previously found to be associated with a self-report index of good health and with lower mortality in the Alameda County studies were related to several measures of health in a cohort of 880 men and 973 women, ages 35-69, who were participants in the Tecumseh Community Health Study. The health measures were prevalence of three diagnoses--coronary heart disease (CHD), hypertension, and chronic bronchitis--and levels of five risk factors--systolic and diastolic blood pressures, serum total cholesterol, blood glucose, and FEV1. Four of the practices--desirable relative weight, physical activity, never having smoked, and moderate or no alcohol drinking--were associated significantly with one or more of the health measures. Eating breakfast, limited between-meal eating, and sleeping 7 or 8 hr were not related to the health measures. Combining all seven health practices into an index produced a measure that was more strongly associated negatively with CHD prevalence than was any one of the component practices. However, the index was no more strongly associated with any of the other health measures than were the relevant separate practices. Desirable weight was more highly associated (negatively) with hypertension and blood pressure than the index was, as was never having smoked with chronic bronchitis (negatively) and FEV1 (positively).Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/25178/1/0000617.pd