Papers by Francis Johnson
Global Journal of Science Frontier Research, 2020
In response to the global COVID-19 pandemic, this work aims to understand the early time evolutio... more In response to the global COVID-19 pandemic, this work aims to understand the early time evolution and the spread of the disease outbreak with a data driven approach. To this effect, we applied Susceptible- Infective-Recovered/Removed (SIR) epidemiological model on the disease. Additionally, we used the Machine Learning linear regression model on the historical COVID-19 data to predict the earlier stage of the disease. The evolution of the disease spread with the Mathematical SIR model and Machine Learning regression model for time series forecasting of the COVID-19 data without, and with lags and trends, was able to capture the early spread of the disease. Consequently, we suggest that if using a more advanced epidemiological model, and sophisticated machine learning regression models on the COVID-19 data, we can understand, as well as predict the long time evolution of the disease spread.
Environmental Innovation and Societal Transitions, 2019
Abstract As cities in East Africa keep growing, so too will demand for charcoal – the region’s pr... more Abstract As cities in East Africa keep growing, so too will demand for charcoal – the region’s preferred urban fuel – placing increasing pressure on rural landscapes where it is produced. How can charcoal production and supply be made sustainable? What are the implications of sustainable charcoal policies and practices for achieving a low-carbon pathway and protecting the environment? This paper presents case study research focusing on Kitui County, one of the main charcoal production areas in Kenya. Risk and uncertainty of sustainable charcoal policies in Kitui were assessed using complementary methods of stakeholder workshops, informant interviews and agent-based modelling. This interdisciplinary approach combined policy research and simulation modelling, where local perspectives and data were included directly in the modelling. These methods facilitated critique of behaviour concerning agency and corruption. Stakeholders valued the ability to access detailed information on micro-interactions and consider policy performance regarding both financial flows and biomass extraction.
Journal of magnetic resonance (San Diego, Calif. : 1997), Jan 15, 2018
Test disk electrodes were fabricated from carbon nanotubes (CNT) using the Carbon Nanotube Templa... more Test disk electrodes were fabricated from carbon nanotubes (CNT) using the Carbon Nanotube Templated Microfabrication (CNT-M) technique. The CNT-M process uses patterned growth of carbon nanotube forests from surfaces to form complex patterns, enabling electrode sizing and shaping. The additional carbon infiltration process stabilizes these structures for further processing and handling. At a macroscopic scale, the electrochemical, electrical and magnetic properties, and magnetic resonance imaging (MRI) characteristics of the disk electrodes were investigated; their microstructure was also assessed. CNT disk electrodes showed electrical resistivity around 1 Ω·cm, charge storage capacity between 3.4 and 38.4 mC/cm, low electrochemical impedance and magnetic susceptibility of -5.9 to -8.1 ppm, closely matched to that of tissue (∼-9 ppm). Phantom MR imaging experiments showed almost no distortion caused by these electrodes compared with Cu and Pt-Ir reference electrodes, indicating the...
Planetary and Space Science, 1970
Abstract The rates of heat input into the mesosphere and lower thermosphere are calculated and co... more Abstract The rates of heat input into the mesosphere and lower thermosphere are calculated and compared with the heat losses. The worldwide average eddy diffusion coefficient required to maintain continuity in the heat budget is calculated and found to vary from ...
Proceedings of the IEEE, 1964
Clinical cancer research : an official journal of the American Association for Cancer Research, Jul 30, 2016
To determine the maximum tolerated dose and to assess the safety, tolerability, and potential act... more To determine the maximum tolerated dose and to assess the safety, tolerability, and potential activity of LB-100, a first-in-class small molecule inhibitor of protein phosphatase 2A (PP2A) in adult patients with progressive solid tumors. LB-100 was administered intravenously daily for 3 days in 21-day cycles in a 3+3 dose-escalation design. There were 29 patient entries over 7 dose escalations. One patient stopped treatment after one dose because of an acute infection and was re-enrolled after recovery; each course was analyzed as a separate patient entry. Two patients had dose-limiting toxicity (reversible increases in serum creatinine or calculated serum creatinine clearance) at the 3.1mg/m2 level. Probable or possible study drug-related Grade 3 adverse events occurred in 6 (20.7%) patients [anemia (n=2), decreased creatinine clearance, dyspnea, hyponatremia, and lymphopenia]. Ten (50%) of 20 response-evaluable patients had stable disease for 4 or more cycles. One patient with pan...
DNA repair, Oct 29, 2016
Translesion DNA synthesis (TLS) operates when replicative polymerases are blocked by DNA lesions.... more Translesion DNA synthesis (TLS) operates when replicative polymerases are blocked by DNA lesions. To investigate the mechanism of mammalian TLS, we employed a plasmid bearing a single 7-(deoxyadenosine-N(6)-yl)-aristolactam I (dA-AL-I) adduct, which is generated by the human carcinogen, aristolochic acid I, and genetically engineered mouse embryonic fibroblasts. This lesion induces A to T transversions at a high frequency. The simultaneous knockouts of the Polh, Poli and Polk genes did not influence the TLS efficiency or the coding property of dA-AL-I, indicating that an unknown DNA polymerase(s) can efficiently catalyze the insertion of a nucleotide opposite the adduct and subsequent extension. Similarly, knockout of the Rev1 gene did not significantly affect TLS. However, knockout of the Rev3l gene, coding for the catalytic subunit of polζ, drastically suppressed TLS and abolished dA-AL-I to T transversions. The results support the idea that Rev1 is not essential for the cellular ...
Semiannual Status Report Period Ending 15 Mar 1975 Texas Univ Dallas, Jun 1, 1975
The Environmental Law Reporter, 2014
Biofuels for Poverty Reduction and Environmental Restoration : the Case of Jatropha in Zambia
Petroleum-recovery techniques are being developed for the many shallow, low-productive, heavy-oil... more Petroleum-recovery techniques are being developed for the many shallow, low-productive, heavy-oil sand deposits in Kansas, Oklahoma, and Missouri. In 1971, the Bureau of Mines began a field experiment in Labette County, Kansas, using a recovery method that combines chemical explosive fracturing to create communication between wells with solvent injection to dilute the oil and lower its viscosity. Through laboratory tests, a commercial solvent that significantly lowered the viscosity of the oil and yet retained the asphaltenes in solution was selected. Core soaking experiments using the solvent selected revealed that the length of time the solvent is allowed to stay in contact with the core and the surface area-to-volume ratio in the core materially affects the SolFrac recovery process. The fracturing, production, and injection techniques used in the field experiment are described and the production results given.
The Nordic Centre of Excellence for Strategic Adaptation Research (NORD-STAR) aspires to a Nordic... more The Nordic Centre of Excellence for Strategic Adaptation Research (NORD-STAR) aspires to a Nordic region that can adapt sustainably to the impacts of climate change and the consequences of climate policy. Pursuing innovative science, sound economic analysis and effective communication, NORD-STAR aims to enable Nordic stakeholders to design and implement successful adaptation policy and practice. NORD-STAR fosters a strategic approach to climate adaptation, making a novel contribution to the Nordic adaptation knowledge base. NORD-STAR is funded by the Norden Top-Level Research Initiative sub-programme 'Effect Studies and Adaptation to Climate Change.' www.nord-star.info The NORD-STAR Working Paper Series has been established to expedite the dissemination of research results from NORD-STAR and to facilitate scientific discussion. All manuscripts submitted for publication in the Working Paper Series are subject to peer-review. The Working Paper Series is managed by an editorial team consisting of an editor and the co-leaders of the NORD-STAR Science Domain.
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Papers by Francis Johnson