Successive Steps Research Articles

Powder Metallurgy Processing to Enhance Superelasticity and Shape Memory in Polycrystalline Cu–Al–Ni Alloys: Reference Material for Additive Manufacturing

Shape memory alloys (SMAs) are functional materials with a wide range of applications, from the aerospace sector to the biomedical field. Nowadays, there is a worldwide interest in developing SMAs through powder metallurgy like additive manufacturing (AM), which allows innovative building processes. However, producing SMAs using AM techniques is particularly challenging because of the microstructure required to obtain optimal functional properties. This aspect is critical in the case of Cu–Al–based SMAs, due to their high elastic anisotropy, making them brittle in polycrystalline form. In this work, we approached the processing of a Cu–Al–Ni SMA following a specific powder metallurgy route: gas atomization of a pre-alloyed melt; compaction of the atomized powders through hot isostatic pressing; and a final hot rolling plus thermal treatments. Then, the microstructure of the material was characterized by electron microscopy showing a specific [001] texture in the rolling direction that improved the functional behavior. The successive processing steps produce an increase of about 40 °C in the martensitic transformation temperatures, which can be well controlled and reproduced through the developed methodology. The thermomechanical functional properties of superelasticity and shape memory were evaluated on the final SMA. Outstanding, fully recoverable superelastic behavior of 4.5% in tension, as well as a ±5% full shape memory recovery in bending, were reported for many cycles. These experiments demonstrate the enhanced mechanical and functional properties obtained in polycrystalline Cu–Al–Ni SMAs by powder metallurgy. The present results pave the road for producing this kind of SMA with the new AM technologies, which always produce polycrystalline components and can improve their processes taking the powder metallurgy SMA, here produced, as reference material.

Toffoli gate implementation method based on Margolus gate on four or more qubits

This paper considers the method of building the Toffoli Gate based on the Margolus Gate on four or more qubits. In the first part of the considered method, the modification of the Margolus gate on four or more qubits is suggested. In the second part of the method, the modification of the Margolus gate is transformed into the modification of the Toffoli gate implementation using step-by-step phase rotation compensations. The phase rotation compensation for an N-qubit quantum circuit can be performed with N successive steps, where at each step the gates with phase rotation pi/2^(s-1) are added, where s is the step number, starting from one. The compensation phase requires 2 two-qubit gates and 2N-1 one-qubit gates.

Successful steps on the way to a non-invasive glucose monitoring system

Successful steps on the way to a non-invasive glucose monitoring system

An efficient droplet-vitrification cryopreservation procedure for high imperatorin-yielding hairy root clones of Urena lobata

The valuable anti-cancer and anti-inflammatory secondary metabolite, imperatorin, has been found in the hairy roots (HRs) of Urena lobata. However, an increasing number of problems related to cryo-injury and cryoprotectant toxicity could potentially reduce the quality of root clones, highlighting the need to develop a reliable technique for long-term preservation. Based on the impact of the successive steps of the initial droplet-vitrification procedure employed for cryopreservation of HRs using the histological evaluation of plasmolysis, various selected factors were independently investigated. The maximum plasmolysis was observed after the preculture with 0.5 M sucrose (46.59 %) and the dehydration treatment (48.32 %). In the improved cryopreservation procedure, when prolonged preculture for 72 h in liquid WPM with 0.3 M sucrose and dehydration in the appropriate vitrification solution, which included 30 % (w/v) glycerol and 50 % (w/v) sucrose, for 10 min at 0 °C, the plasmolysis in the two steps was significantly reduced in comparison with the untreated control. The cryopreserved HRs could increase their regeneration to 93.3 % and regenerated root length to 4.65 cm. Their growth and imperatorin production were almost the same as those of untreated controls after three to five subsequent subcultures. Our results have demonstrated that our new approach, which only focuses on the key factors that significantly increase the plasmolysis, modifies their level to fit with the HR cells of U. lobata. The early application of the plasmolysis evaluation method may immediately screen the impact of factors on individual root cells instead of spending time and cost evaluating the recovery of root tips at each step to develop an efficient cryopreservation procedure.

Quantitative analysis of cannabinoids and metabolites in oral fluid by volumetric absorptive microsampling combined with UHPLC-HRMS.

With recent evolution of cannabis legalization around the world and multiplication of cannabis derived products, identifying and qualifying cannabis consumption has a proven interest. Although blood, plasma, and urine are common matrices widely used in toxicology laboratories, oral fluid presents specific advantages. In the context of doping tests, addiction consultation or roadside checks, where other matrices are impractical to collect or can be adulterated, oral fluid is a promising matrix that allows a non-invasive, rapid, and monitored self-sampling. However, available devices required a consequent volume of oral fluid,more than 250 µL, sometimes difficult to collect. We present here a fully optimized quantitative method for seven cannabinoids, including four metabolites, in oral fluid, Δ9-tetrahydrocannabinol, 11-hydroxy-Δ9-tetrahydrocannabinol and 11-nor-9-carboxy-Δ9-tetrahydrocannabinol; cannabidiol, 7-hydroxy and 7-carboxycannabidiol; and cannabinol. After self-collection of 20 µL using an accurate and precise volumetric absorptive microsampling device (VAMS®), cannabinoids were derivatized with 2-fluoro-1-methylpyridinium p-toluenesulfonate to increase sensitivity. The successive steps of the proposed method, including biosampling, 1 h sample preparation with derivatization, and acquisition by ultrahigh-performance liquid chromatography coupled to high-resolution mass spectrometry, were fully optimized. A limit of quantification of 0.5 ng/mL (≈10 pg per sampling) was thus targeted, adapted to the legal threshold required by the authorities and to clinical monitoring. Applied to six cannabis consumers, the proposed method made it possible to quantify in 20 µL oral fluid samples, Δ9-tetrahydrocannabinol ranging from 0.5 to 6236 ng/mL, cannabidiol from 0.6 to 190 ng/mL and cannabinol from 0.5 to 118 ng/mL.

Assessing Species Richness with Camera Trap Surveys During Five Years of Large-Scale Mining Disruptions

In the Northern Cape Province of South Africa, an investigation was launched into the impact of large-scale open-pit mining on wildlife ecology and populations, more specifically on the animal species richness and detection rates across different vegetation types. Using camera traps, we monitored a 43,000-hectare area, which included active mining areas and adjacent lands, over a period of five years (2020–2024). Data on 44 animal species ranging from small mammals to large megaherbivores were collected, with a large variation in species richness across the study site being observed. The detection of species that are of conservation concern, such as the vulnerable Temminck’s ground pangolin (Smutsia temminckii) and endangered mountain reedbuck (Redunca fulvorufula), highlighted additional potential risks that mining activities pose to biodiversity in the area, emphasizing the importance of monitoring biodiversity in areas that are impacted by large-scale anthropogenic and mining activities. Furthermore, the results suggest that some areas may require a more targeted approach to conservation in order to mitigate the disruptive effect of mining. Benchmarking the species present and proving the presence of endangered and vulnerable species prove the successful first steps into understanding habitat disruption caused by mining activities and will guide future conservation and management efforts.

Indene as an alternative hydrogen carrier: Performance of supported noble metal catalysts for indene and indane hydrogenation

We propose in this article the use of indene, obtained from the light fraction of coal tar rectification, as a Liquid Organic Hydrogen Carrier (LOHC), with a thorough study of its hydrogenation. The hydrogenation process, conducted on noble metal catalysts (Pd, Pt, Rh, and Ru) supported by activated carbon or alumina, involves the rapid conversion of indene to indane, followed by the formation of cis- and trans-hydrindane. Carbon-supported catalysts exhibited faster reactions rates, with catalytic activities varying among metal phases, Rh and Ru being the most active. Indene was found to have an inhibitory effect on the hydrogenation reactions. While Ru catalysts enhance cracking, Rh catalysts are the most selective for total hydrogenation. The study highlights that Ru catalysts favour cracking reactions more than Rh. The proposed reaction mechanisms involve successive steps and follow a Langmuir-Hinshelwood type kinetics, confirming the inhibitory effect of indene.

Non-target risk assessment of Cotesia typhae, a potential biological control agent of the Mediterranean corn borer

Biocontrol of exotic insect pests can be achieved by introducing natural enemies from the native range. This method has been successful in controlling many pests worldwide, but negative effects on local non-targets have sometimes occurred. Before the introduction of exotic macro-organisms useful for crop protection, a risk assessment is mandatory under EU regulations. In this study, we assessed the non-target risks of the larval parasitoid Cotesia typhae (Hymenoptera, Braconidae), a potential agent for inundative biocontrol of the Mediterranean corn borer Sesamia nonagrioides (Lepidoptera, Noctuidae), both natives to Sub-Saharan Africa. The effects of C. typhae on 8 non-target species was determined by sequential analysis under laboratory conditions, including tests of acceptance, development monitoring, olfactory attractiveness and in planta parasitism test. The results varied considerably between species. By multiplying the probability of outcome of the successive steps of the parasitism process, we estimated that non-target species had lower average risks of C. typhae development (1 % of non-target larvae at risk) and of induced mortality (5 %) compared to S. nonagrioides larvae (41 and 42 % respectively). The highest mortality risk in planta was observed for the cattail stemborer, Nonagria typhae (9 %), although it was still lower than for the target species (33 %). These host range results and the low survival capacity of the parasitoid at winter temperatures, suggest a low long-term environmental risk, which is supported by the estimation of the global risk index proposed by van Lenteren et al. (2003). The host range and impact of C. typhae in field conditions will soon be determined.

An assessment of Rare Earth Elements in borehole cores from the Ermelo, Witbank and Waterberg Coalfields, South Africa: Focus on mode of occurrence

There is currently limited knowledge concerning South African coal deposits as hosts for rare earth elements (REE). This project aims to determine the concentration of REE, including yttrium and scandium (REY+Sc) in various coal seams and adjacent sediments in borehole cores from the Ermelo, Witbank, and Waterberg coalfields in South Africa. Coal petrography (maceral count and vitrinite reflectance), XRD, XRF, sequential chemical extraction procedure (SCEP) before ICP-MS, and mineral liberation analysis (MLA) were conducted on the coal and associated sediment samples. The coals were inertinite-rich, medium-rank bituminous coal, with moderate to high ash content. The two dominant minerals in all the coalfields are kaolinite and quartz, except for sample ZBS2M, where dolomite was dominant. The dominant major oxides are Al2O3, SiO2, Fe2O3, and CaO, which concur with the XRD results. The ICP-MS results following SCEP indicated that both coal and the associated sediments were light REY+Sc dominant. There was also an elevation of medium REY+Sc in the Witbank coal's associated sediment samples. Notably, the samples with the highest REY+Sc results were the sediment samples. The Waterberg samples had the lowest REY+Sc from both the coal (less than 2 μg/g to 7 μg/g) and associated sediments (2 μg/g to 15 μg/g). While the highest REY+Sc was yielded from the Witbank-associated sediments (500 μg/g to 2,500 μg/g). The carbonate fraction step proved to be the most successful leaching step, as most REY+Sc was recovered in that step for all coalfields. In addition to the carbonate fraction, the silicates and sulfide fraction in the Witbank samples, and the ion-exchangeable fraction for the Waterberg-associated sediments samples proved successful in leaching out the REY+Sc. MLA determined that monazite and xenotime in all the coal samples were the REY+Sc-bearing minerals.

Unlocking Photocycloaddition Reactivity of Tropolone by Cage-Confined Visible-Light Photocatalysis for Multilevel Selective Transformation.

The precise asymmetric photochemical transformation of organic compounds containing multiple reactive sites presents significant progress in synthetic chemistry. Herein, we report an unprecedented visible-light-induced cascade transformation of tropolone cyclic triene derivatives by using chiral photoactive metal-organic cages (cPMOCs) as enzyme-mimicking multipocket photocatalysts. The cage-confined photocatalysis promotes three successive elementary steps, i.e., enantioselective [2 + 2] photocycloaddition with chalcone, regio-, and diastereoselective α-ketol rearrangement, and a stereoselective 1,3-acyl shift, resulting in bicyclo[3.2.2]nonane skeleton with multichiral-centers unattainable by other methods. This study demonstrates how complex synthetic challenges of peri-, chemo-, and stereoselectivities could be subtly manipulated by cage-confined supramolecular catalysis for exploration of new reactivities.

Assessment of land restoration from optical satellite image time-series

Abstract. Ecosystem conservation and restoration is recognized by the international community as a key strategy for human well-being as well as our planet’s health. Assessing the efficiency of actions implemented in this context is essential, as their application on the ground may prove challenging. In the present paper, we present a methodology for characterising vegetation regeneration. This methodology has been developed and tested at the scale of the Sao Paulo state. It is based on two successive steps. Firstly, annual land cover maps are produced with breakpoints detection and Random Forest classification. This process is performed on biophysical variables derived from more than 10 000 optical images (2016 – 2021 included) and 4774 reference data. Secondly, we applied an expert-based rules algorithm to derive land regeneration map from annual land cover time series. The distinction is made between natural and anthropogenic regeneration. The accuracy assessment shows an overall accuracy of more than 80% for both the annual land cover maps and the regeneration map.

Lipoxygenase activity in tropical fish: Changes during surimi processing and some biochemical characterization in lizardfish (Saurida tumbil).

The lipoxygenase (LOX) activity of major tropical fish used for surimi production, including threadfin bream (TB), lizardfish (LZ), and goatfish (GF), was measured in the gills, skin, and muscle. The highest LOX activity was observed in the LZ samples (p<0.05), with the gills exhibiting the greatest activity at 376.56U/mg (p<0.05). The highest peroxide value was detected in the TB samples, particularly in the gills (p<0.05). Docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) were the main polyunsaturated fatty acids in all the tissues and surimi. The total lipid and DHA contents of washed mince reduced considerably after the screw press process. Although LOX activity decreased during surimi production, a residual activity of 21.33U/g was observed in the finished surimi. LOX was partially purified and characterized from LZ gills. The purification was conducted using two successive chromatographic steps, Sephacryl S-200 and diethylaminoethyl (DEAE)-sepharose, resulting in a 3.52% yield and a 22.43-fold increase in purity. The optimum activity was found at 25°C and pH 7.5, with pH stability between 6.0 and 8.5. The relatively high thermal stability at 4°C-10°C suggested that LOX might contribute to fish lipid oxidation during cold storage. The enzyme was thermally inactivated at 60°C. The preferred substrate was EPA. LOX from the LZ gills was inhibited by 1mM ethylenediaminetetraacetic acid and activated by 1mM Fe2+, Na+, and Ca2+. PRACTICAL APPLICATION: Elucidating lipoxygenase activity and lipid oxidation in various tropical fish tissues, as well as understanding the characteristics of LOX, can help take appropriate postharvest actions to afford high-quality surimi.

Efficient interaction-based offline runtime verification of distributed systems with lifeline removal

Runtime Verification (RV) refers to a family of techniques in which system executions are observed and confronted to formal specifications, with the aim of identifying faults. In offline RV, observation and verification are done in two separate and successive steps. In this paper, we define an approach to offline RV of Distributed Systems (DS) against interactions. Interactions are formal models describing communications within a DS. A DS is composed of subsystems deployed on different machines and interacting via message passing to achieve common goals. Therefore, observing executions of a DS entails logging a collection of local execution traces, one for each subsystem, collected on its host machine. We call multi-trace such observational artifacts. A major challenge in analyzing multi-traces is that there are no practical means to synchronize the ends of observations of all the local traces. We address this via an operation called lifeline removal, which we apply on-the-fly to the specification during the verification of a multi-trace once a local trace has been entirely analyzed. This operation removes from the interaction the specification of actions occurring on the subsystem that is no longer observed. This may allow further execution of the specification by removing potential deadlock. We prove the correctness of the resulting RV algorithm and introduce two optimization techniques, which we also prove correct. We implement a Partial Order Reduction (POR) technique by selecting a one-unambiguous action (as a unique first step to a linearization) whose existence is determined via the lifeline removal operator. Additionally, Local Analyses (LOC), i.e., the verification of local traces, can be leveraged during the global multi-trace analysis to prove failure more quickly. Experiments illustrate the application of our RV approach and the benefits of our optimizations.

Inversion of downhole resistivity properties through infrared spectroscopy and whole‐rock geochemistry using machine‐learning

AbstractThe electrical properties of rocks are widely used in the geophysical exploration of natural resources, such as minerals, hydrocarbons and groundwater. In mining exploration, the primary goal is to map electrically anomalous geological features associated with different mineralization styles, such as clay alteration haloes, metal oxides and sulphides, weathered crystalline rocks or fractured zones. As such, the reconciliation of geophysical data with geological information (geochemistry, mineralogy, texture and lithology) is a critical step and can be performed based on petrophysical properties collected either on core samples or as downhole measurements. Based on data from 189 diamond drill cores collected for uranium exploration in the Athabasca Basin (Saskatchewan, Canada), this paper presents a case study of reconciliation of downhole resistivity probing with core sample geochemistry and short‐wave infrared spectroscopy (350–2500 nm) through three successive steps: (i) multivariate analysis of resistivity and other petrophysical properties (porosity, density) against geochemical and infrared spectroscopy information to characterize electrical properties of rocks with respect to other physical parameters, (ii) a machine‐learning workflow integrating geochemistry and spectral signatures in order to infer synthetic resistivity logs along with uncertainties. The best model in the basin was Light Gradient‐Boosting Machine with pairwise log‐ratio, which yielded a coefficient of determination R2 = 0.80 (root mean square error = 0.16), and in the basement, support vector regression with data fusion of infrared spectroscopy and pairwise log‐ratios on geochemistry yielded R2 = 0.82 (root mean square error = 0.35); (iii) the best model was then fitted on an area that was excluded from the original dataset (Getty Russell property) in order to infer synthetic resistivity logs for that zone. Software code is publicly available. This workflow can be re‐used for the valorization of legacy datasets.

Cryo-electron microscopy structure of the di-domain core of Mycobacterium tuberculosis polyketide synthase 13, essential for mycobacterial mycolic acid synthesis.

Mycobacteria are known for their complex cell wall, which comprises layers of peptidoglycan, polysaccharides and unusual fatty acids known as mycolic acids that form their unique outer membrane. Polyketide synthase 13 (Pks13) of Mycobacterium tuberculosis, the bacterial organism causing tuberculosis, catalyses the last step of mycolic acid synthesis prior to export to and assembly in the cell wall. Due to its essentiality, Pks13 is a target for several novel anti-tubercular inhibitors, but its 3D structure and catalytic reaction mechanism remain to be fully elucidated. Here, we report the molecular structure of the catalytic core domains of M. tuberculosis Pks13 (Mt-Pks13), determined by transmission cryo-electron microscopy (cryoEM) to a resolution of 3.4 Å. We observed a homodimeric assembly comprising the ketoacyl synthase (KS) domain at the centre, mediating dimerization, and the acyltransferase (AT) domains protruding in opposite directions from the central KS domain dimer. In addition to the KS-AT di-domains, the cryoEM map includes features not covered by the di-domain structural model that we predicted to contain a dimeric domain similar to dehydratases, yet likely lacking catalytic function. Analytical ultracentrifugation data indicate a pH-dependent equilibrium between monomeric and dimeric assembly states, while comparison with the previously determined structures of M. smegmatis Pks13 indicates architectural flexibility. Combining the experimentally determined structure with modelling in AlphaFold2 suggests a structural scaffold with a relatively stable dimeric core, which combines with considerable conformational flexibility to facilitate the successive steps of the Claisen-type condensation reaction catalysed by Pks13.

Collaborative design approach to identify research and innovation needs within the European smart building community.

Upgrading the level of smartness in buildings can significantly contribute to improve our quality and sustainability of living, through increased energy efficiency, optimised resource management, and improved air quality and comfort. However, the fragmented nature of the sector makes it challenging to identify what is technically, socially and economically achieved today in Europe in terms of building smartness, and what should be developed and financially supported tomorrow to accelerate the roll-out of smart and energy efficient buildings. This paper introduces the collaborative process developed to involve a large community of experts in detecting and formalising research and innovation gaps related to smart buildings. This process is composed of four successive steps: 1) a communication phase to invite volunteer experts to join the proposed task forces; 2) The organisation and facilitation of online brainstorming workshops to identify research & innovation (R&I) gaps; 3) the collective drafting of a white paper synthesising the brainstorming outcomes; and 4) an open consultation to collect additional external feedback before finalising the white paper. The collaborative process developed was tested over 18 months and implemented on 12 different topics relying on 27 brainstorming workshops. Building on the collective knowledge of 135 participants, it enabled identification a significant series of R&I gaps related to smart buildings. The collective sessions as well as the open consultation phases showed overall some clear convergence on the gaps identified. It can therefore be concluded the outcome of the collaborative process reached a consensus among the targeted innovation community. The feedback collected on the process, shows that the frequency, duration and attendance of the brainstorming workshops proposed were very relevant, while the selection of online participatory tools could still be improved. This process could be replicated in other frameworks where research and innovation gaps are sought for.

From experimentation to scaling: what shapes the funnel of AI adoption?

ABSTRACT Firms tend to manage the diffusion of complex and uncertain technologies through a ‘funnel', whereby firms first experiment (test and learn), then decide to exploit and scale technology. We study how internal and external factors typically affecting Artificial Intelligence (AI) adoption influence the successive steps of the funnel for a sample of large firms worldwide. We demonstrate that competition influences AI adoption more at the exploitation than at the experimentation phase. Conversely, technology complements are more relevant at the start of the funnel, in contrast to organizational complements which are most relevant to ensure embedding of AI technologies in business practices.

Differential Hall Effect Metrology for Electrical Characterization of Advanced Semiconductor Layers

Semiconductor layers employed in fabricating advanced node devices are becoming thinner and their electrical properties are diverging from those established for highly crystalline standards. Since these properties also change as a function of depth within the film, accurate carrier profiling solutions are required. The Differential Hall Effect (DHE) technique has the unique capability of measuring mobility and carrier concentration (active carriers) through the depth of a semiconductor film. It comprises making successive sheet resistance and sheet Hall coefficient measurements as the thickness of the electrically active layer at a test region is reduced through successive material removal steps. Difference equations are then used to process the data and plot the desired depth profiles. The fundamentals of DHE were established in 1960s. Recently, the adaption of electrochemical processing for the material removal steps, and the integration of all other functionalities in a Differential Hall Effect Metrology (DHEM) tool, has made this technique more practical and accurate and improved its depth resolution to a sub-nm range. In this contribution, we review the development history of this important technique and present data from recent characterization work carried out on Si, Ge and SiGe layers.

Square-Planar Nickel Bis(phosphinopyridyl) Complexes for Long-Lived Photocatalytic Hydrogen Evolution.

Phosphinopyridyl ligands are used to synthesize a class of Ni(II) bis(chelate) complexes, which have been comprehensively characterized in both solid and solution phases. The structures display a square-planar configuration within the primary coordination sphere, with axially positioned labile binding sites. Their electrochemical data reveal two redox couples during the reduction process, suggesting the possibility of accessing two-electron reduction states. Significantly, these complexes serve as robust catalysts for homogeneous photocatalytic H2 evolution. In a system utilizing an organic photosensitizer and a sacrificial electron donor, an optimal turnover number of 27,100 is achieved in an alcohol-containing aqueous solution. A series of photophysical and electrochemical measurements were conducted to elucidate the reaction mechanism of photocatalytic hydrogen generation. Density function theory calculations propose a catalytic pathway involving two successive one-electron reduction steps, followed by two proton discharges. The sustained photocatalytic activity of these complexes stems from their distinct ligand system, which includes phosphine and pyridine donors that aid in stabilizing the low oxidation states of the Ni center.

Competence in Unsustainability Resolution—A New Paradigm

Environmental unsustainability in coupled human–nature systems is accumulating. Yet, there is no accreditation requirement for unsustainability resolution competency in higher education. Thus, a new and complete representation of the pedagogy for unsustainability resolution competence has been induced, using what is already available and working. The nature of unsustainability problems points to collaboration and holism attitudes. Resolution requires social skills, namely participation, perspective taking, and the generation of social capital, and cognitive skills, namely project management, knowledge building, and modeling. Resolution is scaffolded in three successive steps during the collaborative process within a systems approach: (i) collapse complexity; (ii) select a path/trajectory; and (iii) operationalize a plan. The hierarchically cumulative abilities toward unsustainability resolution competence are to source data and information about the coupled human–nature system (SEARCH); simplify the dynamics of the human–nature system (SIMULATE); generate and test alternative paths and end points for the coupled human–nature system (STRATEGIZE); chose a favorable path among the available alternatives (SELECT); operationalize the favorable path into a plan (strategy–program–project) with measurable management and policy objectives (IMPLEMENT); and develop criteria/indicators to monitor and adjust when necessary the implementation of the plan toward system goals (STEER). For each one of these learning objectives, the Bloom’s taxonomy and a progression from behaviorist through cognitivist to constructivist tools apply. The development of mastery requires the comparison and contrast of many similar cases with the same unsustainability problem and project-based learning with specific cases for deep learning. In this way, it is the resolutions of unsustainability in human–nature systems that will be accumulating.