Future Waves
Oswald Lemus
Step One. A specialized marine radar incorporating a vertically-polarized antenna provides lower-wind operability and longer-range observations, resulting in more accurate directional spectra. The radar rotates continuously and uses coherent-on-receive technology to make hundreds of thousands of wavefield velocity measurements per second.
Because the Futurewaves radar directly measures ocean-surface velocities, instead of power-backscatter, it is fully self-calibrating for virtually all sea conditions and can provide accurate measurements over a broad range of wave periods from less than 4.5s up to 28s.
Step Two. Highly advanced, proprietary algorithms developed over 5+ years with Navy R&D funding produce a full directional spectrum with no limitations or assumptions about spectral shape or spreading, with an accuracy possibly exceeding that of a wave buoy (which can produce limited or even false directional information).
Our patent-pending algorithms can combine Doppler data from multiple radars to produce more timely and accurate sea-state information and forecast, which is particularly useful on large vessels or vessels radar-mounting locations that have limited-fields-of-view.
Course and speed recommendations can be set to minimize motions of greatest concern (heave, pitch, roll, or combinations of these). Predictions include motion statistics as well as forecasting of the specific upcoming motions due to the surrounding waves, up to two minutes in advance.
A specially-designed simple yet flexible user interface developed with inputs from hundreds of hours of at-sea interation with ship captains and crew allows for easy access for most important information while still allowing more sophisticated users to access more detailed information.
Through years of research and live testing in the field, GDAPS has refined which equipment and algorithms are best suited for ocean-wave sensing, timing, and vessel motion forecasting leading to the most accurate tool available today.
Under contract with the Office of Naval Research, GDAPS originally developed and employed a 450 pound Advanced Wave Sensing Radar (AWSR). After teaming with the industry-leading radar developers, the FutureWaves specialized radar is now packaged to be easily installed and utilized by any commercial customer.
Alongside the radar system, FutureWaves employs a sophisticated Motion Reference Unit (MRU), metocean sensors, and various GPS nodes. Much like the radar system, years of testing has taken place to determine what performance level is required of these components to optimize system performance.
Briski generally says: "Biological invasions can cause extinctions, cost trillions of dollars in damage and control, and spread diseases." But that is not necessarily the case, which is why Briski prefers a neutral term "non-native species" instead of "invaders." And their numbers are growing rapidly, making large-scale understandings and predictions of invasion patterns crucial to protect environments, economies, and societies.
"We investigated whether the number of non-native species reflects patterns in global biodiversity. We then looked at whether certain groups of species are disproportionately prone to establish in new areas." To do this, the researchers compiled a comprehensive list of non-native species described to date -- there are around 37,000 worldwide -- and grouped them according to biological taxonomy -- from phyla to classes and families. Then, they put them in relation to global biodiversity. The result: whether microscopically small or the size of a hippopotamus, whether on land or under water -- on average about 1% of all living organisms have been transported by humans somewhere in the world.
"Of course, the data situation varies greatly in some cases" Briski points out. Species on land are generally better studied than those in the water. A greater research effort would therefore probably uncover a significant number of new non-native species in marine habitats. Other understudied groups, such as microorganisms, are also likely to be vastly underestimated in non-native species inventories. In addition, richer countries tend to have more research on non-native species than poorer countries. "It is therefore quite possible that there are many non-native species in the tropical rainforest that we simply don't know about."
The researchers found that some groups have excessively established outside their native range, including mammals, birds, fishes, insects, spiders, and plants. Briski: "The most commonly reported introduced non-native species tend to be those that have been introduced intentionally for agriculture, horticulture, forestry or other purposes." And unwanted species always come along with the wanted ones, for example as stowaways on ships. "Nobody wanted to introduce rats, but they have spread across the globe alongside humans," says Briski.
Overall, the results indicate a huge potential for future biological invasions in various species groups. Briski: "If only one per cent of global biodiversity has been affected so far, we can assume that the extent will increase considerably." The randomness of the process is remarkable: "Sooner or later, any species can use our transport manners and routes to reach areas to which it would not naturally have access." The magnitude of environmental and socio-economic impacts due to new invasions is thus likely to rise substantially in the coming decades, particularly as trade and transport accelerate and shift, connecting distant countries and their unique species pools. Briski and colleagues call for urgent action to prevent future introductions and to control the most damaging invaders that are already established.
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Viral reproduction of SARS-CoV-2 provides opportunities for the acquisition of advantageous mutations, altering viral transmissibility, disease severity, and/or allowing escape from natural or vaccine-derived immunity. We use three mathematical models: a parsimonious deterministic model with homogeneous mixing; an age-structured model; and a stochastic importation model to investigate the effect of potential variants of concern (VOCs). Calibrating to the situation in England in May 2021, we find epidemiological trajectories for putative VOCs are wide-ranging and dependent on their transmissibility, immune escape capability, and the introduction timing of a postulated VOC-targeted vaccine. We demonstrate that a VOC with a substantial transmission advantage over resident variants, or with immune escape properties, can generate a wave of infections and hospitalisations comparable to the winter 2020-2021 wave. Moreover, a variant that is less transmissible, but shows partial immune-escape could provoke a wave of infection that would not be revealed until control measures are further relaxed.
Since the SARS-CoV-2 virus was first identified in humans in late 2019, the resulting global pandemic has caused, as of 23rd July 2021, over 190 million confirmed COVID-19 cases and above 4.1 million reported deaths with COVID-19 disease1. As the pandemic continues globally, high SARS-CoV-2 incidence rates act to increase the risk of the virus acquiring additional advantageous mutations2, potentially altering transmissibility, severity, and escape from natural or vaccine-derived immunity.
A range of different VOCs are found in genomically sequenced specimens in England. Of those reported by 31st May 2021 (noting that delays between specimen collection and sequencing can extend to up to three weeks), there had been 846 genomically sequenced samples of B.1.351, 151 of P.1, 43 of B.1.1.7 with E484K, and 9426 of B.1.617.2 variant cases (excluding variant cases not linked to a known COVID-19 case or with provisional sequencing/genotyping results)30. We remark that the frequency of variants among sequenced samples may not be representative of variant frequencies more broadly due to nonrandom selection of samples sent for sequencing.
The infectious-disease dynamics of SARS-CoV-2 result from a complex interaction between the circulation of multiple variants, vaccination, NPI policy, and adherence. Mathematical modelling approaches are an avenue for testing the sensitivity of these dynamics to the underlying assumptions and conveying uncertainty, with the caveat that models must balance biological realism with mathematical and computational tractability and parameter identifiability31. Models have previously demonstrated their usefulness as a tool offering insights on the dynamics of pathogens with multiple lineages32,33. At the original time of writing (May 2021), there was burgeoning interest in modelling to explore the effects of VOCs on the trajectory of the SARS-CoV-2 epidemic. One such paper used a deterministic compartmental model to simulate the impact of the potential introduction of the more transmissible variant, B.1.1.7, into a Colombian population in which previous strains were dominant34. The authors considered the effect on the prevalence of hospitalisation and deaths, and concluded that the introduction of such a variant would necessitate increased NPIs and an increased pace of vaccinations, though the potential immune-escape characteristics of a VOC were not explored. Another example study, considering the spread of the B.1.1.7 variant in Ontario, Canada, devised a two-strain mathematical framework to model both a resident and a mutant-type viral population to estimate the time at which a mutant variant is able to take over a resident-type strain during an emerging infectious-disease outbreak35.
In this study, we use three mathematical models of novel SARS-CoV-2 variant dynamics to evaluate the drivers, and the likely timescales, of SARS-CoV-2 VOC epidemics in England. We demonstrate that a VOC can cause subsequent epidemic outbreaks comparable in magnitude to earlier waves in the pandemic if it possesses either a large transmission advantage over the existing resident variants, or the ability to evade immunity (either infection- or vaccine-derived). Further, even when a novel variant is less transmissible than the locally resident variants, immune escape can lead to a marked wave of infection and consequential hospitalisations. In addition, the reduced transmissibility of such a VOC can allow it to remain difficult to detect, until NPIs are reduced. Finally, we explore the relative timing of VOC-targeted vaccines versus the establishment of community transmission of an emergent VOC, showing a multitude of projected possibilities that demonstrate the need to remain attentive to all potential scenarios.
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