671 research outputs found
Mineral potential modelling of orogenic gold systems in the granites-tanami Orogen, Northern Territory, Australia: A multi-technique approach
In this study we adopted fuzzy inference system (FIS), transformed predictor map-based random forest (RF) and feed-forward deep neural network (FF-DNN) approaches to mineral potential modelling (MPM) of the Granites-Tanami Orogen (GTO), Northern Territory, Australia, to (i) predict gold prospectivity, and (ii) compare the performance of these models to those previously generated in the study area. The current study, which utilized 19 predictor maps previously developed by Roshanravan et al. (2020) in the framework of a mineral systems approach, took into consideration the learnings gained and results obtained from previous approaches to modelling the gold potential of the GTO (Roshanravan et al., 2020: continuous fuzzy gamma, geometric average, data-driven index overlay and non-transformed predictor map-based RF; Roshanravan et al., 2021: cuckoo optimization algorithm). Importantly, our study area extending over > 46,000 km2 in the GTO, represents one of the few, if not the only, areas worldwide that has been subjected to eight different modelling techniques, an approach that delivered unique insights that cannot be achieved by utilizing a single technique. For example, our multi-technique approach enabled us to study what effect predictor maps may have on model performance and resulting mineral potential maps. In the case of data-driven MPM with RF, arguably-one of the most popular machine learning techniques, the effect of non-transformed (i.e., original) and transformed (i.e., derivative) predictor maps has never been evaluated simultaneously. To achieve this, we generated a transformed predictor map-based RF potential model with the aim of comparing it to the non-transformed predictor map-based RF model of Roshanravan et al. (2020). The FF-DNN and Mamdani-type FIS approaches to MPM were carried out specifically for the purpose of comparing and further investigating the modelling results. With respect to the Mamdani-type FIS, the concentration-area (C-A) fractal technique served to more objectively determine thresholds of the underlying mathematical functions, a novel approach that aids in reducing bias resulting from human input and expert opinion. The thresholded results demonstrate that the RF potential map generated with transformed predictor maps outperformed all other data-driven and continuous models. Overall, our multi-technique approach to MPM and the comparing and contrasting of a large set of resulting gold potential models, not only offered insights that helped to develop and calibrate new tools and techniques but also delivered what we believe are more robust gold exploration targets. As a result, we strongly recommend to using a multi-technique approach to MPM, which we hope will soon replace the currently accepted and widely utilized single-technique approach
Unconformity-type uranium systems: a comparative review and predictive modelling of critical genetic factors
A review of descriptive and genetic models is presented for unconformity-type uranium deposits with particular attention given to spatial representations of key process components of the mineralising system and their mappable expressions. This information formed the basis for the construction of mineral potential models for the world's premier unconformity-style uranium provinces, the Athabasca Basin in Saskatchewan, Canada (>650,000 t U3 O8), and the NW McArthur Basin in the Northern Territory, Australia (>450,000 t U3 O8). A novel set of ‘edge’ detection routines was used to identify high-contrast zones in gridded geophysical data in support of the mineral potential modelling. This approach to geophysical data processing and interpretation offers a virtually unbiased means of detecting potential basement structures under cover and at a range of scales. Fuzzy logic mineral potential mapping was demonstrated to be a useful tool for delineating areas that have high potential for hosting economic uranium concentrations, utilising all knowledge and incorporating all relevant spatial data available for the project area. The resulting models not only effectively ‘rediscover’ the known uranium mineralisation but also highlight several other areas containing all of the mappable components deemed critical for the accumulation of economic uranium deposits. The intelligence amplification approach to mineral potential modelling presented herein is an example of augmenting expert-driven conceptual targeting with the powerful logic and rationality of modern computing. The result is a targeting tool that captures the current status quo of geospatial and exploration information and conceptual knowledge pertaining to unconformity-type uranium systems. Importantly, the tool can be readily updated once new information or knowledge comes to hand. As with every targeting tool, these models should not be utilised in isolation, but as one of several inputs informing exploration decision-making. Nor should they be regarded as ‘treasure maps’, but rather as pointers towards areas of high potential that are worthy of further investigation
Stereoselective routes to aryl substituted γ-butyrolactones and their application towards the synthesis of highly oxidised furanocembranoids
Titanium chelate addition of aryl nucleophiles to cyclopropyl aldehyde 6 followed by a tin-catalyzed one-pot retro-aldol, acetalisation and lactonisation sequence afforded cis and trans γ-aryllactone acetals. A γ-furyllactone derived by this approach was further transformed in two steps to model compounds for the oxidised northeastern sectors of selected Pseudopterogorgia diterpenoids
Fiskalische Wirkungen der Einführung eines gesetzlichen Mindestlohns
Der BMAS Forschungsbericht "Fiskalische Wirkungen der Einführung eines gesetzlichen Mindestlohns" quantifiziert die mindestlohnbedingten Veränderungen von Einnahmen- und Ausgaben des öffentlichen Gesamthaushalts, also im Steuer- und Transfersystem sowie auf der Ebene der Gesetzlichen Sozialversicherungen. Ausgangspunkt für die Berechnungen stellt ein Literaturüberblick zum aktuellen Stand der quantitativ orientierten Forschung zu den Wirkungen des gesetzlichen Mindestlohns in Deutschland dar. Die durchgeführten Berechnungen erfolgen dann mit Hilfe des Mikrosimulationsmodells der Prognos auf Basis der Daten des sozio-oekonomischen Panels. Zur Abgrenzung mindestlohninduzierter Lohneffekte werden im Datensatz verschiedene Beschäftigtengruppen identifiziert. Für diese Gruppen werden kontrafaktische Stundenlöhne und Arbeitszeiten bestimmt, die als Grundlage für die Modellrechnungen "ohne Mindestlohn" genutzt werden. Abschließend erfolgt die Abschätzung der Mindestlohneffekte auf die fiskalischen Einnahmen und Ausgaben für unterschiedliche Szenarien, um die mögliche Spannbreite der Effekte aufzuzeigen.The BMAS research report "Fiscal Effects of the Introduction of a Statutory Minimum Wage" quanti-fies the minimum wage-related changes in income and expenditure in the overall public budget, i.e. in the tax and transfer system and the statutory social insurance scheme. The starting point for these calculations is an overview of the literature on the latest quantitative research into the impact of the statutory minimum wage in Germany. The calculations are then carried out with the help of Prognos‘ microsimulation model based on data from the Socio-Economic Panel. In the data set, various em-ployee groups are identified to differentiate minimum wage effects. Counterfactual hourly wages and working hours are determined for these groups, which are then used as the basis for the "without minimum wages" model calculations. Finally, the minimum wage effects on fiscal income and ex-penditure are estimated for different scenarios to show the possible range of effects
On the complete classification of the unitary N=2 minimal superconformal field theories
Aiming at a complete classification of unitary N=2 minimal models (where the
assumption of space-time supersymmetry has been dropped), it is shown that each
modular invariant candidate of a partition function for such a theory is indeed
the partition function of a minimal model. A family of models constructed via
orbifoldings of either the diagonal model or of the space-time supersymmetric
exceptional models demonstrates that there exists a unitary N=2 minimal model
for every one of the allowed partition functions in the list obtained from
Gannon's work.
Kreuzer and Schellekens' conjecture that all simple current invariants can be
obtained as orbifolds of the diagonal model, even when the extra assumption of
higher-genus modular invariance is dropped, is confirmed in the case of the
unitary N=2 minimal models by simple counting arguments.Comment: 53 pages; Latex; minor changes in v2: intro expanded, references
added, typos corrected, footnote added on p31; renumbering of sections; main
theorem reformulated for clarity, but contents unchanged. Minor revisions in
v3: typos corrected, footnotes 5, 6 added, lemma 1 and section 3.3.2
rewritten for greater generality, section 3.3 review removed. To appear in
Comm. Math. Phy
Abnormal Motor Activity and Thermoregulation in a Schizophrenia Rat Model for Translational Science
Schizophrenia is accompanied by altered motor activity and abnormal thermoregulation; therefore, the presence of these symptoms can enhance the face validity of a schizophrenia animal model. The goal was to characterize these parameters in freely moving condition of a new substrain of rats showing several schizophrenia-related alterations.Male Wistar rats were used: the new substrain housed individually (for four weeks) and treated subchronically with ketamine, and naive animals without any manipulations. Adult animals were implanted with E-Mitter transponders intraabdominally to record body temperature and locomotor activity continuously. The circadian rhythm of these parameters and the acute effects of changes in light conditions were analyzed under undisturbed circumstances, and the effects of different interventions (handling, bed changing or intraperitoneal vehicle injection) were also determined.Decreased motor activity with fragmented pattern was observed in the new substrain. However, these animals had higher body temperature during the active phase, and they showed wider range of its alterations, too. The changes in light conditions and different interventions produced blunted hyperactivity and altered body temperature responses in the new substrain. Poincaré plot analysis of body temperature revealed enhanced short- and long-term variabilities during the active phase compared to the inactive phase in both groups. Furthermore, the new substrain showed increased short- and long-term variabilities with lower degree of asymmetry suggesting autonomic dysregulation.In summary, the new substrain with schizophrenia-related phenomena showed disturbed motor activity and thermoregulation suggesting that these objectively determined parameters can be biomarkers in translational research
Metabolic network alterations as a supportive biomarker in dementia with Lewy bodies with preserved dopamine transmission
Search for supersymmetry in events with b-quark jets and missing transverse energy in pp collisions at 7 TeV
Results are presented from a search for physics beyond the standard model
based on events with large missing transverse energy, at least three jets, and
at least one, two, or three b-quark jets. The study is performed using a sample
of proton-proton collision data collected at sqrt(s) = 7 TeV with the CMS
detector at the LHC in 2011. The integrated luminosity of the sample is 4.98
inverse femtobarns. The observed number of events is found to be consistent
with the standard model expectation, which is evaluated using control samples
in the data. The results are used to constrain cross sections for the
production of supersymmetric particles decaying to b-quark-enriched final
states in the context of simplified model spectra.Comment: Submitted to Physical Review
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