This paper reports a numerical study on the aeroacoustic response of a rectangular T-junction with merging mean flows. The primary motivation of the work is to explain the high sound amplification, recently seen experimentally, when introducing a small merging bias flow. The acoustic results are found solving the compressible Linearized Navier–Stokes Equations (LNSEs) in the frequency domain, where the base flow is first obtained using RANS with a k–ε turbulence model. The model predicts the measured scattering data well, including the amplitude and Strouhal number for the peak amplification, if the effect of eddy viscosity damping is included. It is found that the base flow changes significantly with the presence of a small bias flow. Compared to pure grazing flow a strong unstable shear layer is created in the downstream main duct starting from the T-junction trailing edge. This means that the main region of vortex–sound interaction is moved away from the junction to a downstream region much larger than the junction width. To analyze the sound amplification in this region Howe׳s energy corollary and the growth of acoustic density are used.

Many shark and ray species (Class Chondrichthyes, herein ‘sharks’) are threatened by overfishing. Tackling this requires implementation of context-specific fisheries management measures, which are both technically effective and socio-economically feasible. Here we explore the cost-effectiveness of various input-oriented management measures for mitigating capture of seven priority shark taxa (i.e., threatened and CITES-listed species) in a small-scale longline mixed-species shark fishery in Indonesia, where there is a need to balance difficult trade-offs between conservation and socio-economic objectives. We apply Boosted Regression Trees (BRT) to analyse five years of landings and profit data, to identify and assess the relative influence of different plausible management measures (e.g., effort restrictions, gear restrictions, spatio-temporal closures). We then use predictive models to inform a semi-quantitative assessment of the hypothetical cost-effectiveness of these management measures, based on the estimated conservation benefits (reduced risk of capture of priority taxa) and socio-economic cost (relative profit foregone). Our results show that fishery closures in January–March, depth limits at <100 m, hook limits at <500 hooks, and gear restrictions on bottom longlines could have the greatest relative conservation impact for lowest profit foregone. However, there are clear trade-offs between taxa, with these measures primarily benefiting Critically Endangered bottlenose wedgefish (Rhynchobatus Australiae) and scalloped hammerheads (Sphyrna lewini), while potentially increasing pressure on Vulnerable silky sharks (Carcharhinus falciformis) and Endangered mako sharks (Isurus spp.). When shark fishing is important for economic welfare, and entire fishery closures or buy-outs are unfeasible, managing small-scale shark fisheries for multiple outcomes may require hard choices. This may require prioritising slow-growing Critically Endangered taxa for protection – by restricting fishing during seasons and at depths in which they are most susceptible to capture – while faster-growing taxa can continue to provide benefits for coastal communities.

Public health measures to prevent, detect, and respond to events are essential to control public health risks, including infectious disease outbreaks, as highlighted in the International Health Regulations (IHR). In light of the outbreak of 2019 novel coronavirus disease (COVID-19), we aimed to review existing health security capacities against public health risks and events.We used 18 indicators from the IHR State Party Annual Reporting (SPAR) tool and associated data from national SPAR reports to develop five indices: (1) prevent, (2) detect, (3) respond, (4) enabling function, and (5) operational readiness. We used SPAR 2018 data for all of the indicators and categorised countries into five levels across the indices, in which level 1 indicated the lowest level of national capacity and level 5 the highest. We also analysed data at the regional level (using the six geographical WHO regions).Of 182 countries, 52 (28%) had prevent capacities at levels 1 or 2, and 60 (33%) had response capacities at levels 1 or 2. 81 (45%) countries had prevent capacities and 78 (43%) had response capacities at levels 4 or 5, indicating that these countries were operationally ready. 138 (76%) countries scored more highly in the detect index than in the other indices. 44 (24%) countries did not have an effective enabling function for public health risks and events, including infectious disease outbreaks (7 [4%] at level 1 and 37 [20%] at level 2). 102 (56%) countries had level 4 or level 5 enabling function capacities in place. 32 (18%) countries had low readiness (2 [1%] at level 1 and 30 [17%] at level 2), and 104 (57%) countries were operationally ready to prevent, detect, and control an outbreak of a novel infectious disease (66 [36%] at level 4 and 38 [21%] at level 5).Countries vary widely in terms of their capacity to prevent, detect, and respond to outbreaks. Half of all countries analysed have strong operational readiness capacities in place, which suggests that an effective response to potential health emergencies could be enabled, including to COVID-19. Findings from local risk assessments are needed to fully understand national readiness capacities in relation to COVID-19. Capacity building and collaboration between countries are needed to strengthen global readiness for outbreak control.None.

The amount of phosphorus in the total environment is finite, yet recent estimates suggest that more than enough phosphate ore resources exist in the lithosphere to meet future increases in demand during the next century. Still, it remains unclear how the accessibility of this resource stock – which is heterogeneous in terms of grade and location – will change as currently accessible resources are utilized, as extraction and processing technologies develop, and as the relative economic costs vary. This study uses an economic framework, the World Trade Model with Rectangular Choice-of-Technology, to link estimates of known geological resources of various grades with the technically and economically accessible reserves. Using the most recent public data on phosphate ore stocks and mining and technological capacity, this study estimates that the ~ 400,000 teragrams (Tg) of known apatite ore (> 1% P2O5 content) equate to ~ 110,000 Tg when converted to potential reserves (~ 30% P2O5) using existing technologies, with over half of these remaining potential reserves converted from resources with grades below 20% P2O5. Corresponding global reserves are estimated at ~ 70,000 Tg using the Rectangular Choice-of-Technology model, but since any reserve estimate is contingent on the state of the world economy, a set of five illustrative scenarios are constructed to show how this estimate can vary between ~ 67,000 and ~ 98,000 Tg with only a small number of changes to the economic and technical parameters and variables. Calculating accessibility using consistent definitions for resources and reserves while distinguishing between grades not only creates a clearer picture of remaining non-renewable resources, but creates a framework that can be used to explore future geopolitical scenarios about ore availability, extraction technologies, supply networks, and global commodity prices.

Between now and the year 2000 the U.S.A. will use as much in the way of resources, including energy, as in all its previous history. To cover this energy need, offshore petroleum operations are, and will be, very important. However, the continental shelf is also an area of great environmental concern, and accidents occurring in the course of these operations could cause great harm to the environment. The U.S. Geological Survey is responsible for insuring that such operations are conducted safely. In order to prevent accidents or, should they occur, minimize the damage done, the Survey has devised a number of safety systems, which it is still refining. It also has the legal power to make sure that these regulations are fully observed, and a comprehensive inspection system has been developed.