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This text is geared toward students who have an undergraduate degree or extensive coursework in engineering or the physical sciences and who wish to develop their understanding of the essential topics of applied mathematics. The methods covered in the chapters form the core of analysis in engineering and the physical sciences. Readers will learn the solutions, techniques, and approaches that they will use as academic researchers or industrial R&D specialists. For example, they will be able to understand the fundamentals behind the various scientific software packages that are used to solve technical problems (such as the equations describing the solid mechanics of complex structures or the fluid mechanics of short-term weather prediction and long-term climate change), which is crucial to working with such codes successfully. Detailed and numerous worked problems help to ensure a clear and well-paced introduction to applied mathematics. Computational challenge problems at the end of each chapter provide students with the opportunity for hands-on learning and help to ensure mastery of the concepts. Adaptable to one- and two-semester courses.
We present a sediment-mixing process model of till genesis based on data from surface tills of the Saginaw lobe terrain in lower Michigan. Our research uses a spatial approach to understanding glacial landsystems and till genesis. We sampled calcareous till at 336 upland sites and at 17 sites in lacustrine sediment of the Saginaw Lake plain. The loamy tills have bimodal grain-size curves, with a fine-texture mode near the silt–clay boundary and a sand mode. Spatial grouping analysis suggests that tills can be divided into six groups, each with different textures and clay mineral compositions that vary systematically down-ice. The similarity among groups with respect to the silt–clay mode and clay mineralogy argues for a common origin for the fines—illite-rich lacustrine sediment of the Saginaw Lake plain. Fine-textured sediments were probably entrained, transported, and deposited down-ice as till, which also becomes sandier and enriched in kaolinite, reflecting increasing mixing with shallow sandstone bedrock with distance from the lacustrine clay source. Clayey tills on the flanks of the Saginaw terrain may reflect proglacial ponding against nearby uplands. A process model of progressive down-ice mixing of preexisting fine lake sediments with crushed/abraded sandstone bedrock helps to better explain till textures compared with a purely crushing/abrasion process model.
Toad bones, sometimes occurring in great numbers in pit features and other contexts in Native American village and mound sites in the Appalachian Summit, have been interpreted as evidence that toads were consumed, used for their purportedly hallucinogenic toad venom, placed as ritual deposits, or naturally entrapped/intrusive. A paucity or lack of bones of the head in some contexts is suggestive of decapitation and consumption of toads. Alternatively, bones of the head may be less preservable, recoverable, or identifiable. This study examines toad remains on Appalachian Summit late precontact and contact period sites, reviews previous experimentation, and presents a new experimental study undertaken to identify agencies of accumulation. We propose that toads were regularly consumed and possibly as part of ritualized events associated with village and mound construction. The temporal and geographic restriction of this practice to the Pisgah and Qualla phases of the Appalachian Summit suggests subsistence ethnicity as alluded to in historical accounts.
Herbicides used in sugarbeet are commonly adapted from other row crops and may cause injury and yield loss, often associated with environmental and edaphic factors. Glyphosate-resistant (GR) waterhemp in sugarbeet requires PRE herbicide including S-metolachlor for its control. The objectives of this research were to evaluate sugarbeet tolerance to PRE S-metolachlor including air temperature and soil water content interactions with soil series in field and growth chamber experiments. Results from field experiments conducted in 12 environments in 2015, 2016, and 2017 indicated 2.16 or 4.32 kg ai ha-1S-metolachlor applied PRE reduced sugarbeet density and stature but did not reduce root yield, sucrose content, or recoverable sucrose compared to the untreated control in environments with soils with less than 3.5% organic matter (OM) and receiving greater than 40 mm cumulative rainfall within 14 d after planting. In the growth chamber, sugarbeet density and shoot fresh weight following S-metolachlor application was influenced by soil moisture content, air temperature, and soil series but not by S-metolachlor rate. Sugarbeet density was reduced 15% and sugarbeet shoot fresh weight reduced 106% when S-metolachlor was applied to a Glyndon sandy loam (2.6% OM, 9.5% clay) at 100% field capacity (FC) and 14 C compared to S-metolachlor application to a Fargo silty clay (7.7% OM and 54% clay) at 100% FC and 21 C. It is concluded that field selection is an important criterion for managing waterhemp with S-metolachlor applied and tolerance in sugarbeet; more so than S-metolachlor application rate.
The introduction of 2,4-D-resistant soybean and cotton provided growers a new postemergent active ingredient to include in weed management programs. The technology raises concerns regarding potential 2,4-D off-target movement to sensitive vegetation, and spray droplet size is the primary management factor focused on to reduce spray particle drift. The objective of this study was to investigate the droplet size distribution, droplet velocity, and particle drift potential of glyphosate plus 2,4-D choline pre-mixture (Enlist Duo®) applications with two commonly used venturi nozzles in a low-speed wind tunnel. Applications with the TDXL11004 nozzle had larger DV0.1 (291 µm), DV0.5 (544 µm), and DV0.9 (825 µm) values compared to the AIXR11004 nozzle (250, 464, and 709 µm, respectively), and slower average droplet velocity (8.1 m s-1) compared to the AIXR11004 nozzle (9.1 m s-1). Nozzle type had no influence on drift deposition (P = 0.65), drift coverage (P = 0.84), and soybean biomass reduction (P = 0.76). Although the TDXL11004 nozzle had larger spray droplet size, the slower spray droplet velocity could have influenced the nozzle particle drift potential. As a result, both TDXL11004 and AIXR11004 nozzles had similar spray drift potential. Further studies are necessary to understand the impact of droplet velocity on drift potential at field scale, and test how different tank solutions, sprayer configurations, and environmental conditions could influence the droplet size and velocity dynamics and consequent drift potential in pesticide applications.
We investigate the factors associated with the occurrence and abundance of external and blood parasites in African penguins (Spheniscus demersus), an endangered seabird that breeds exclusively on the coasts of Namibia and South Africa. External parasites were collected using the dust-ruffling method from 171 African Penguins admitted at a rehabilitation facility in the Western Cape, South Africa. Additionally, blood smears were obtained upon admission and weekly during rehabilitation and examined for blood parasites. Fleas Parapsyllus longicornis humboldti, ticks Ornithodoros capensis and lice Austrogoniodes demersus were recovered from 93, 63 and 40%, respectively, of the penguins upon admission to the centre. Rescue location and age group were identified as significant determinants of flea abundance, whereas month of admission was a significant determinant of tick abundance. Blood parasites were also common on admission, with Babesia being the most frequent (46% prevalence) whereas Borrelia was recorded sporadically (1.2%) and Plasmodium was recorded once. The prevalence and abundance of ticks on admission was positively associated with Babesia infection on admission. Our findings demonstrate the variability and contributing factor of parasite infections in an endangered species of penguin, and highlight the need for additional research on the parasite–host dynamics involving these potential disease vectors.
BRAC, an international development organization based in Bangladesh, engages community health workers called Shasthya Shebikas (SS) to implement home fortification of foods with micronutrient powders (MNP). We identified factors associated with home visits by SS, at different levels of the BRAC programme-delivery hierarchy, to implement home-fortification interventions.
We conducted a cross-sectional survey, semi-structured interviews, and collected programme-related data from sub-districts included in the caregiver survey of BRAC’s home-fortification programme and performed multilevel logistic regression modelling to investigate factors associated with home visits by SS.
Sixty-eight sub-districts in Bangladesh.
Caregivers of children aged 6–59 months (n 1408) and BRAC’s SS (n 201).
Households with older children (0·55; 0·42, 0·72; P < 0·001) and located >300 m from the SS’s house (0·67; 0·50, 0·89; P = 0·006) were less likely to have been visited by the SS, whereas those with caregivers who had ≥5 years of schooling (1·53; 1·10, 2·12; P = 0·011) were more likely to have been visited by the SS (adjusted OR; 95 % CI). Households in the catchment area of older SS aged >50 years (0·44; 0·21, 0·90; P = 0·025) were less likely to have been visited by the SS, whereas those with SS who received incentives of >800 BDT (3·00; 1·58, 5·58; P = 0·001) were more likely to have been visited by the SS (adjusted OR; 95 % CI).
The number of home visits is a function of the characteristics of SS, factors that characterize the households they serve and characteristics of their organizational context, particularly to implement home fortification of foods with MNP.
Acifluorfen is a non-systemic PPO-inhibiting herbicide commonly used for postemergence Palmer amaranth control in soybean, peanut, and rice across the southern United States. Concerns have been raised regarding herbicide selection pressure and particle drift, increasing the need for application practices that optimize herbicide efficacy while mitigating spray drift. Field research was conducted in 2016, 2017, and 2018 in Mississippi and Nebraska to evaluate the influence of a range of spray droplet sizes [150 μm (Fine) to 900 μm (Ultra Coarse)] using acifluorfen to create a novel Palmer amaranth management recommendation using pulse width modulation (PWM) technology. A pooled site-year generalized additive model (GAM) analysis suggested that 150 μm (Fine) droplets should be used to obtain the greatest Palmer amaranth control and dry biomass reduction. Nevertheless, GAM models indicated that only 7.2% of the variability observed in Palmer amaranth control was due to differences in spray droplet size. Therefore, location-specific GAM analyses were performed to account for geographical differences to increase the accuracy of prediction models. GAM models suggested that 250 μm (Medium) droplets optimize acifluorfen efficacy on Palmer amaranth in Dundee, MS, and 310 μm (Medium) droplets could sustain 90% of maximum weed control. Specific models for Beaver City, NE indicated that 150 μm (Fine) droplets provide maximum Palmer amaranth control, and 340 μm (Medium) droplets could maintain 90% of greatest weed control. For Robinsonville, MS, optimal Palmer amaranth control could be obtained with 370 μm (Coarse) droplets, and 90% maximum control sustained with 680 μm (Ultra Coarse) droplets. Differences in optimal droplet size across location could be a result of convoluted interactions between droplet size, weather conditions, population density, plant morphology, and soil fertility levels. Future research should adopt a holistic approach to identify and investigate the influence of environmental and application parameters to optimize droplet size recommendations.
The Canadian Resident Matching Service (CaRMS) selection process has come under scrutiny due to the increasing number of unmatched medical graduates. In response, we outline our residency program's selection process including how we have incorporated best practices and novel techniques.
We selected file reviewers and interviewers to mitigate gender bias and increase diversity. Four residents and two attending physicians rated each file using a standardized, cloud-based file review template to allow simultaneous rating. We interviewed applicants using four standardized stations with two or three interviewers per station. We used heat maps to review rating discrepancies and eliminated rating variance using Z-scores. The number of person-hours that we required to conduct our selection process was quantified and the process outcomes were described statistically and graphically.
We received between 75 and 90 CaRMS applications during each application cycle between 2017 and 2019. Our overall process required 320 person-hours annually, excluding attendance at the social events and administrative assistant duties. Our preliminary interview and rank lists were developed using weighted Z-scores and modified through an organized discussion informed by heat mapped data. The difference between the Z-scores of applicants surrounding the interview invitation threshold was 0.18-0.3 standard deviations. Interview performance significantly impacted the final rank list.
We describe a rigorous resident selection process for our emergency medicine training program which incorporated simultaneous cloud-based rating, Z-scores, and heat maps. This standardized approach could inform other programs looking to adopt a rigorous selection process while providing applicants guidance and reassurance of a fair assessment.
In turbulent flows subject to strong background rotation, the advective mechanisms of turbulence are superseded by the propagation of inertial waves, as the effects of rotation become dominant. While this mechanism has been identified experimentally (Dickinson & Long, J. Fluid Mech., vol. 126, 1983, pp. 315–333; Davidson, Staplehurst & Dalziel, J. Fluid Mech., vol. 557, 2006, pp. 135–144; Staplehurst, Davidson & Dalziel, J. Fluid Mech., vol. 598, 2008, pp. 81–105; Kolvin et al.Phys. Rev. Lett., vol. 102, 2009, 014503), the conditions of the transition between the two mechanisms are less clear. We tackle this question experimentally by tracking the turbulent front away from a solid wall where jets enter an otherwise quiescent fluid. Without background rotation, this apparatus generates a turbulent front whose displacement recovers the
law classically obtained with an oscillating grid (Dickinson & Long, Phys. Fluids, vol. 21 (10), 1978, pp. 1698–1701) and we further establish the scale independence of the associated transport mechanism. When the apparatus is rotating at a constant velocity perpendicular to the wall where fluid is injected, not only does the turbulent front become mainly transported by inertial waves, but advection itself is suppressed because of the local deficit of momentum incurred by the propagation of these waves. Scale-by-scale analysis of the displacement of the turbulent front reveals that the transition between advection and propagation is local both in space and spectrally, and takes place when the Rossby number based on the considered scale is of order unity, or equivalently, when the scale-dependent group velocity of inertial waves matched the local advection velocity.
Brominated flame retardants (BFR) are primarily used as flame retardant additives in insulating materials. These lipophilic compounds can bioaccumulate in animal tissues, leading to human exposure via food ingestion. Although their concentration in food is not yet regulated, several of these products are recognised as persistent organic pollutants; they are thought to act as endocrine disruptors. The present study aimed to characterise the occurrence of two families of BFRs (hexabromocyclododecane (HBCDD) and polybrominated diphenyl ethers (PBDE)) in hen eggs and broiler or pig meat in relation to their rearing environments. Epidemiological studies were carried out on 60 hen egg farms (34 without an open-air range, 26 free-range), 57 broiler farms (27 without an open-air range, 30 free-range) and 42 pig farms without an open-air range in France from 2013 to 2015. For each farm, composite samples from either 12 eggs, five broiler pectoral muscles or three pig tenderloins were obtained. Eight PBDE congeners and three HBCDD stereoisomers were quantified in product fat using gas chromatography–high-resolution mass spectrometry, or high-performance liquid chromatography–tandem mass spectrometry, respectively. The frequencies of PBDE detection were 28% for eggs (median concentration 0.278 ng/g fat), 72% for broiler muscle (0.392 ng/g fat) and 49% for pig muscle (0.403 ng/g fat). At least one HBCDD stereoisomer was detected in 17% of eggs (0.526 ng/g fat), 46% of broiler muscle (0.799 ng/g fat) and 36% of pig muscle (0.616 ng/g fat). Results were similar in concentration to those obtained in French surveillance surveys from 2012 to 2016. Nevertheless, the contamination of free-range eggs and broilers was found to be more frequent than that of conventional ones, suggesting that access to an open-air range could be an additional source of exposure to BFRs for animals. However, the concentration of BFRs in all products remained generally very low. No direct relationship could be established between the occurrence of BFRs in eggs and meat and the characteristics of farm buildings (age, building materials). The potential presence of BFRs in insulating materials is not likely to constitute a significant source of animal exposure as long as the animals do not have direct access to these materials.
The shape gradient is a local sensitivity function defined on the surface of an object which provides the change in a characteristic quantity, or figure of merit, associated with a perturbation to the shape of the object. The shape gradient can be used for gradient-based optimization, sensitivity analysis and tolerance calculations. However, it is generally expensive to compute from finite-difference derivatives for shapes that are described by many parameters, as is the case for typical stellarator geometry. In an accompanying work (Antonsen, Paul & Landreman J. Plasma Phys., vol. 85 (2), 2019), generalized self-adjointness relations are obtained for magnetohydrodynamic (MHD) equilibria. These describe the relation between perturbed equilibria due to changes in the rotational transform or toroidal current profiles, displacements of the plasma boundary, modifications of currents in the vacuum region or the addition of bulk forces. These are applied to efficiently compute the shape gradient of functions of MHD equilibria with an adjoint approach. In this way, the shape derivative with respect to any perturbation applied to the plasma boundary or coil shapes can be computed with only one additional MHD equilibrium solution. We demonstrate that this approach is applicable for several figures of merit of interest for stellarator configuration optimization: the magnetic well, the magnetic ripple on axis, the departure from quasisymmetry, the effective ripple in the low-collisionality
(Nemov et al.Phys. Plasmas, vol. 6 (12), 1999, pp. 4622–4632) and several finite-collisionality neoclassical quantities. Numerical verification of this method is demonstrated for the magnetic well figure of merit with the VMEC code (Hirshman & Whitson Phys. Fluids, vol. 26 (12), 1983, p. 3553) and for the magnetic ripple with modification of the ANIMEC code (Cooper et al.Comput. Phys. Commun., vol. 72 (1), 1992, pp. 1–13). Comparisons with the direct approach demonstrate that, in order to obtain agreement within several per cent, the adjoint approach provides a factor of
in computational savings.
This study examined the long-term effects of a randomized controlled trial of the Family Check-Up (FCU) intervention initiated at age 2 on inhibitory control in middle childhood and adolescent internalizing and externalizing problems. We hypothesized that the FCU would promote higher inhibitory control in middle childhood relative to the control group, which in turn would be associated with lower internalizing and externalizing symptomology at age 14. Participants were 731 families, with half (n = 367) of the families assigned to the FCU intervention. Using an intent-to-treat design, results indicate that the FCU intervention was indirectly associated with both lower internalizing and externalizing symptoms at age 14 via its effect on increased inhibitory control in middle childhood (i.e., ages 8.5–10.5). Findings highlight the potential for interventions initiated in toddlerhood to have long-term impacts on self-regulation processes, which can further reduce the risk for behavioral and emotional difficulties in adolescence.
− The role of the state as an agent of earth system governance has become more complex, contingent, and interdependent. − Although participatory and collaborative processes have contributed to more effective, equitable, and legitimate environmental governance outcomes in some instances, analyses of these processes should be situated within a broader governance perspective, which recasts questions of policy change around questions of power and justice. −The complexity and normative aspects of agency in earth system governance requires new forms of policy evaluation that account for social impacts and the ability of governance systems to adapt. − Many of the core analytical concepts in ESG–Agency scholarship, such as agency, power, authority, and accountability, remain under-theorized. In addition, some types of actors, including women, labor, non-human agents, those who work against earth system governance, and many voices from the Global South, remain largely hidden. − ESG–Agency scholars need to develop research projects and collaborations in understudied regions while also recruiting and supporting scholars in those regions to engage with this research agenda.
The climate crisis requires nations to achieve human well-being with low national levels of carbon emissions. Countries vary from one another dramatically in how effectively they convert resources into well-being, and some nations with low levels of emissions have relatively high objective and subjective well-being. We identify urgent research and policy agendas for four groups of countries with either low or high emissions and well-being indicators. Least studied are those with low well-being and high emissions. Understanding social and political barriers to switching from high-carbon to lower-carbon modes of production and consumption, and ways to overcome them, will be fundamental.
A large share of our food comes from international supply food chains that are difficult to trace. Therefore, consumers are not aware of their environmental and social effects. We analysed the tomato supply system for Germany. Tomatoes consumed in Germany are produced either in The Netherlands by Polish workers and using large amounts of energy, or in Spain by West African workers and depleting the aquifer. The analysis shows the long-distance effects of food consumption that should be considered when designing strategies for a sustainable global food system. Comparable results can be expected for other food products traded around the world.
A growing body of research suggests that deficient emotional self-regulation (DESR) is common and morbid among attention-deficit/hyperactivity disorder (ADHD) patients. The main aim of the present study was to assess whether high and low levels of DESR in adult ADHD patients can be operationalized and whether they are clinically useful.
A total of 441 newly referred 18- to 55-year-old adults of both sexes with Diagnostic and Statistical Manual of Mental Disorders: Fifth Edition (DSM-5) ADHD completed self-reported rating scales. We operationalized DESR using items from the Barkley Current Behavior Scale. We used receiver operator characteristic (ROC) curves to identify the optimal cut-off on the Barkley Emotional Dysregulation (ED) Scale to categorize patients as having high- versus low-level DESR and compared demographic and clinical characteristics between the groups.
We averaged the optimal Barkley ED Scale cut-points from the ROC curve analyses across all subscales and categorized ADHD patients as having high- (N = 191) or low-level (N = 250) DESR (total Barkley ED Scale score ≥8 or <8, respectively). Those with high-level DESR had significantly more severe symptoms of ADHD, executive dysfunction, autistic traits, levels of psychopathology, and worse quality of life compared with those with low-level DESR. There were no major differences in outcomes among medicated and unmedicated patients.
High levels of DESR are common in adults with ADHD and when present represent a burdensome source of added morbidity and disability worthy of further clinical and scientific attention.