Effect of future CO2 and temperature regimes on phytoplankton community composition, biomass and photosynthetic rates in the western English Channel

CO2 storage in the oceans is strongly affected by biological processes. Production of organic matter through phytoplankton photosynthesis drives CO2 sequestration, which feeds back to atmospheric CO2 and global climate. The ongoing increase in atmospheric CO2 and temperature is strongly associated with changes in ocean chemistry and increasing seawater temperatures. To investigate these impacts on coastal phytoplankton under conditions predicted for the year 2100 (pCO2 elevated to 800 µatm and +4 °C temperature), three factorial experiments were conducted with natural communities sampled from the western English Channel (WEC). Elevated pCO2 increased phytoplankton biomass by up to 20-fold while elevated temperature resulted in an increase of up to 14-fold. Light-saturated photosynthetic carbon fixation rates increased > 6-fold under elevated pCO2 while an increase of up to 3-fold resulted from elevated temperature. The combined effects of elevated pCO2 and temperature reduced biomass in late summer and had no effects on biomass in the autumn with no significant effects on photosynthetic carbon fixation rates in either season. Individual treatments of elevated pCO2 and temperature resulted in near mono-specific communities: diatoms in late summer and nanophytoplankton in autumn. Combined effects of both factors resulted in the most diverse phytoplankton communities and promoted increased dinoflagellate and Synechococcus biomass at the expense of diatoms and nanophytoplankton. Elevated pCO2 alone promoted dominance of the harmful algal bloom (HAB) species, Phaeocystis in spring and autumn, while the combination of elevated pCO2 and temperature promoted biomass of the HAB species, Prorocentrum minimum in autumn. The results indicate that experimental simulations of year 2100 pCO2 and temperature may significantly modify phytoplankton community structure with a positive feedback on atmospheric CO2 in late summer and no change on feedback in autumn. In either scenario, no increase in phytoplankton productivity during a period of changes in bulk carbonate chemistry resulting from ongoing anthropogenic carbon uptake, may be expected to negatively influence carbon biogeochemistry in the WEC

Learning regexes to extract router names from hostnames

We present the design, implementation, evaluation, and validation of a system that automatically learns to extract router names (router identifiers) from hostnames stored by network operators in different DNS zones, which we represent by regular expressions (regexes). Our supervised-learning approach evaluates automatically generated candidate regexes against sets of hostnames for IP addresses that other alias resolution techniques previously inferred to identify interfaces on the same router. Conceptually, if three conditions hold: (1) a regex extracts the same value from a set of hostnames associated with IP addresses on the same router; (2) the value is unique to that router; and (3) the regex extracts names for multiple routers in the suffix, then we conclude the regex accurately represents the naming convention for the suffix. We train our system using router aliases inferred from active probing to learn regexes for 2550 different suffixes. We then demonstrate the utility of this system by using the regexes to find 105% additional aliases for these suffixes. Regexes inferred in IPv4 perfectly predict aliases for ≈85% of suffixes with IPv6 aliases, i.e., IPv4 and IPv6 addresses representing the same underlying router, and find 9.0 times more routers in IPv6 than found by prior techniques

STEM Hub Capacity Building to Support Evaluative Thinking and Continuous Improvement: An interim report prepared for Oregon’s Chief Education Office

The Educational Policy Improvement Center (EPIC) and the Center for Research on Lifelong STEM Learning at Oregon State University (OSU) are collaborating on a yearlong capacity-building research project in order to better understand the common and unique features and strengths of Oregon’s STEM Hubs. The project is intended to examine the growth and success of the STEM Hubs and their backbone organizations, and to build capacity for evaluative thinking by supporting Hubs in data-driven decision making and continuous improvement. The project is the first of its kind to systematically examine multiple layers of collaboration between publicly funded STEM-focused organizations, partner organizations, and their broader communities. STEM Hubs are multisector partnerships that link local P–20 educators, workforce and economic development groups, community-based organizations, and business/industry representatives in a collaborative effort to transform the landscape of STEM (Science, Technology, Engineering, and Mathematics) and CTE (Career and Technical Education) teaching and learning. STEM Hubs are implementing strategies that include (amongst others) educator professional development on best practices in STEM instruction; in-and out-of-school, hands-on STEM learning experiences for students; and connections to fast-growing STEM employment opportunities in Oregon

Network hygiene, incentives, and regulation: Deployment of source address validation in the internet

The Spoofer project has collected data on the deployment and characteristics of IP source address validation on the Internet since 2005. Data from the project comes from participants who install an active probing client that runs in the background. The client automatically runs tests both periodically and when it detects a new network attachment point. We analyze the rich dataset of Spoofer tests in multiple dimensions: across time, networks, autonomous systems, countries, and by Internet protocol version. In our data for the year ending August 2019, at least a quarter of tested ASes did not filter packets with spoofed source addresses leaving their networks. We show that routers performing Network Address Translation do not always filter spoofed packets, as 6.4% of IPv4/24 tested in the year ending August 2019 did not filter. Worse, at least two thirds of tested ASes did not filter packets entering their networks with source addresses claiming to be from within their network that arrived from outside their network. We explore several approaches to encouraging remediation and the challenges of evaluating their impact. While we have been able to remediate 352 IPv4/24, we have found an order of magnitude more IPv4/24 that remains unremediated, despite myriad remediation strategies, with 21% unremediated for more than six months. Our analysis provides the most complete and confident picture of the Internet's susceptibility to date of this long-standing vulnerability. Although there is no simple solution to address the remaining long-tail of unremediated networks, we conclude with a discussion of possible non-technical interventions, and demonstrate how the platform can support evaluation of the impact of such interventions over time

Distributed modeling of ablation (1996–2011) and climate sensitivity on the glaciers of Taylor Valley, Antarctica

The McMurdo Dry Valleys of Antarctica host the coldest and driest ecosystem on Earth, which is acutely sensitive to the availability of water coming from glacial runoff. We modeled the spatial variability in ablation and assessed climate sensitivity of the glacier ablation zones using 16 years of meteorological and surface mass-balance observations collected in Taylor Valley. Sublimation was the primary form of mass loss over much of the ablation zones, except for near the termini where melt, primarily below the surface, dominated. Microclimates in ~10 m scale topographic basins generated melt rates up to ten times higher than over smooth glacier surfaces. In contrast, the vertical terminal cliffs on the glaciers can have higher or lower melt rates than the horizontal surfaces due to differences in incoming solar radiation. The model systematically underpredicted ablation for the final 5 years studied, possibly due to an increase of windblown sediment. Surface mass-balance sensitivity to temperature was ~−0.02 m w.e. K−1, which is among the smallest magnitudes observed globally. We also identified a high sensitivity to ice albedo, with a decrease of 0.02 having similar effects as a 1 K increase in temperature, and a complex sensitivity to wind speed

Cryptic bacterial pathogens of diatoms peak during senescence of a winter diatom bloom

Summary Diatoms are globally abundant microalgae that form extensive blooms in aquatic ecosys-tems. Certain bacteria behave antagonistically towards diatoms, killing or inhibiting theirgrowth. Despite their crucial implications to diatom bloom and population health, knowledgeof diatom antagonists in the environment is fundamentally lacking. We report systematic characterisation of the diversity and seasonal dynamics of bacterialantagonists of diatoms via plaque assay sampling in the Western English Channel, where dia-toms frequently bloom. Unexpectedly, peaks in detection did not occur during characteristicspring diatom blooms, but coincided with a winter bloom ofCoscinodiscus, suggesting thatthese bacteria likely influence distinct diatom host populations. We isolated multiple bacterial antagonists, spanning 4 classes and 10 bacterial orders. Nota-bly, a diatom attaching RoseobacterPonticoccus alexandriiwas isolated multiple times, indi-cative of a persistent environmental presence. Moreover, many isolates had no prior reportsof antagonistic activity towards diatoms. We verified diatom growth inhibitory effects of eightisolates. In all cases tested, these effects were activated by pre-exposure to diatom organicmatter. Discovery of widespread ‘cryptic’ antagonistic activity indicates that bacterial patho-genicity towards diatoms is more prevalent than previously recognised. Finally, examination of the global biogeography of WEC antagonists revealed co-occurrence patterns with diatom host populations in marine waters globally

Linking a dermal permeation and an inhalation model to a simple pharmacokinetic model to study airborne exposure to di(n-butyl) phthalate

Six males clad only in shorts were exposed to high levels of airborne di(n-butyl) phthalate (DnBP) and diethyl phthalate (DEP) in chamber experiments conducted in 2014. In two 6 h sessions, the subjects were exposed only dermally while breathing clean air from a hood, and both dermally and via inhalation when exposed without a hood. Full urine samples were taken before, during, and for 48 h after leaving the chamber and measured for key DnBP and DEP metabolites. The data clearly demonstrated high levels of DnBP and DEP metabolite excretions while in the chamber and during the first 24 h once leaving the chamber under both conditions. The data for DnBP were used in a modeling exercise linking dose models for inhalation and transdermal permeation with a simple pharmacokinetic model that predicted timing and mass of metabolite excretions. These models were developed and calibrated independent of these experiments. Tests included modeling of the “hood-on” (transdermal penetration only), “hood-off” (both inhalation and transdermal) scenarios, and a derived “inhalation-only” scenario. Results showed that the linked model tended to duplicate the pattern of excretion with regard to timing of peaks, decline of concentrations over time, and the ratio of DnBP metabolites. However, the transdermal model tended to overpredict penetration of DnBP such that predictions of metabolite excretions were between 1.1 and 4.5 times higher than the cumulative excretion of DnBP metabolites over the 54 h of the simulation. A similar overprediction was not seen for the “inhalation-only” simulations. Possible explanations and model refinements for these overpredictions are discussed. In a demonstration of the linked model designed to characterize general population exposures to typical airborne indoor concentrations of DnBP in the United States, it was estimated that up to one-quarter of total exposures could be due to inhalation and dermal uptake

Using a Markov simulation model to assess the impact of changing trends in coronary heart disease incidence on requirements for coronary artery revascularization procedures in Western Australia

<p>Abstract</p> <p>Background</p> <p>The population incidence of coronary heart disease (CHD) has been declining in Australia and many other countries. This decline has been due to reduced population levels of risk factors for CHD and improved medical care for those at higher risk of CHD. However, there are signs that there may be a slowing down or even reversal in the decline of CHD incidence due to the 'obesity epidemic' and other factors and this will have implications for the requirements for surgical treatments for those with CHD.</p> <p>Methods</p> <p>Using a validated Markov simulation model applied to the population of Western Australia, different CHD incidence trend scenarios were developed to explore the effect of changing CHD incidence on requirements for coronary artery bypass graft (CABG) and percutaneous coronary interventions (PCI), together known as coronary artery revascularization procedures (CARPs).</p> <p>Results</p> <p>The most dominant component of CHD incidence is the risk of CHD hospital admission for those with no history of CHD and if this risk leveled off and the trends in all other risks continued unchanged, then the projected numbers of CABGs and PCIs are only minimally changed. Further, the changes in the projected numbers remained small even when this risk was increased by 20 percent (although it is an unlikely scenario). However, when the other CHD incidence components that had also been declining, namely, the risk of CABG and that of CHD death for those with no history of CHD, were also projected to level off as these were declining in 1998-2000 and the risk of PCI for those with no history of CHD (which was already increasing) was projected to further increase by 5 percent, it had a substantial effect on the projected numbers of CARPs.</p> <p>Conclusion</p> <p>There needs to be dramatic changes to several CHD incidence components before it has a substantial impact on the projected requirements for CARPs. Continued monitoring of CHD incidence and also the mix of initial presentation of CHD incidence is required in order to understand changes to future CARP requirements.</p