Contradictory Assumptions Research Articles

Model authenticity in learning mathematical experimentation: how students perceive and learn from scientist and peer models

The implementation of video modeling examples of mathematical hands-on experimentation may provide students with authentic and, at the same time, not too cognitively overwhelming experiences. However, the effectiveness of video modeling examples can be influenced by different characteristics of the observed models. On the one hand, based on the model-observer similarity hypothesis, it is likely that the observation of peers is particularly conducive to learning. On the other hand, from an authentic learning perspective, the presence of experts is considered to constitute a core design element of authentic learning settings which may foster motivational and cognitive learning outcomes. Against the background of these contradictory assumptions, the present study investigates the effects of observing models with different degrees of authenticity on students’ perceived authenticity, their situational interest, and their knowledge acquisition. We conducted an experimental study with 105 10th graders who observed either peer or scientist models performing a mathematical hands-on experiment in a video recording. As expected, the results show that students perceived the scientist models as more authentic than the peer models. Furthermore, we found neither a direct effect of condition nor an indirect effect mediated by students’ perceived authenticity of the observed models on students’ situational interest and knowledge acquisition. With this study, we contribute to the literature on the conditions and effects of authentic learning.

Understanding snow saltation parameterizations: lessons from theory, experiments and numerical simulations

Abstract. Drifting and blowing snow are important features in polar and high mountain regions. They control the surface mass balance in windy conditions and influence sublimation of snow and ice surfaces. Despite their importance, model representations in weather and climate assessments have high uncertainties because the associated physical processes are complex and highly variable in space and time. This contribution investigates the saltation system, which is the lower boundary condition for drifting and blowing snow models. Using a combination of (previous) measurements and new physics-based modeling with large-eddy simulation (LES), we show that the prevailing parameterizations that describe the saltation system in atmospheric models are based on contradictory assumptions: while some scaling laws are typical of a saltation system dominated by aerodynamic entrainment, others represent a saltation system controlled by splash. We show that both regimes can exist, depending on the friction velocity. Contrary to sand saltation, aerodynamic entrainment of surface particles is not negligible. It is important at low wind speeds, leading to a saltation height and near-surface particle velocity which increase with the friction velocity. In a splash-dominated saltation regime at higher friction velocities, the saltation height and near-surface particle velocity become invariant with the friction velocity and closer to what is observed with sand. These findings are accompanied by a detailed description of the theoretical, experimental and numerical arguments behind snow saltation parameterizations. This work offers a comprehensive understanding of the snow saltation system and its scaling laws, useful for both modelers and experimentalists.

Pharmaco-Analysis of Psychedelics—Philo-Fictions about New Materialism, Quantum Mechanics, Information Science, and the Philosophy of Immanence

Recent developments regarding the pharmacology of psychoactive substances are significant for treating depressions or opioid addictions. Current theories, hypotheses, and models of drug effects assume a cause–effect narrative, which is based on a stimulus/response mechanism. These narratives prioritize effects rather than conscious experiences. In this sense, drug experiences are quickly subsumed into common categories and codes of biological determinism. If subjective experiences are in the focus of the research, it quickly becomes a link to mystical, spiritual, or transcendental narratives. These classifications lead to epistemological doublets (Gadamer). In this article, psychedelic experiences of drug users are analyzed in the frame of the pharmaco-analysis by Deleuze/Guattari. These framed psychedelic experiences are interpreted by means of a non-philosophical approach through philo-fictions (Laruelle), i.e., contradictory assumptions and hyperspeculations. In this respect, the aim of this article is to bring philo-fictions in relation to psychedelic experiences and to discuss them with models of information science, quantum mechanics, new materialism, and the philosophy of immanence. The result will be an open synthesis, with the assumption of further reflections on the agency, immanence, and the wholeness of matter.

New Mechanistic Insights into the Primary Thermolysis Reactions of 1,3,4,6-Tetranitrooctahydroimidazo-[4,5-d]imidazole (BCHMX) from Predictive Local Coupled Cluster Calculations.

Theoretical studies of the decomposition mechanism of energetic materials quite often scrutinize only the primary thermolysis reactions. However, the secondary reactions are crucial, inter alia, for proper building of the combustion models and understanding the autocatalytic processes. In the present study, we applied predictive DLPNO-CCSD(T) calculations to elucidate the kinetics and decomposition mechanism of a novel promising energetic material, 1,3,4,6-tetranitrooctahydroimidazo [4,5-d] imidazole (BCHMX). We identified eight previously unknown BCHMX conformers, both cis and trans in accordance to the spatial position of the H atoms bonded to a carbon bridge. Among them, the relative enthalpies of cis isomers lie in the narrow range ∼10 kJ mol-1 rendering them thermally accessible in the course of decomposition. The radical N-NO2 bond cleavage via one of the novel conformers is the dominant primary decomposition channel of BCHMX with the kinetic parameters Ea = 168.4 kJ mol-1 and log(A, s-1) = 18.5. We also resolved several contradictory assumptions on the mechanism and key intermediates of BCHMX thermolysis. To get a deeper understanding of the decomposition mechanism, we examined a series of unimolecular and bimolecular secondary channels of BCHMX. Among the former reactions, the C-C bond unzipping followed by another radical elimination of a nitro group is the most energetically favorable pathway with an activation barrier ∼113 kJ mol-1. However, contrary to the literature assumptions, the bimolecular H atom abstraction from a pristine BCHMX molecule by a primary nitramine radical product, not the nitro one, followed by another NO2 radical elimination, is the most important bimolecular secondary thermolysis reaction of BCHMX at lower temperatures. The isokinetic temperature of the bimolecular and unimolecular secondary reactions is ∼620 K. Unimolecular reactions might be important in dilute solutions, where bimolecular reactions are suppressed. The secondary reactions considered in the present work might be pertinent in the case of related energetic nitramines (e.g., RDX, HMX, and CL-20).

On the Estimation of Cross-Firm Productivity Spillovers with an Application to FDI

Abstract We develop a novel methodology for the proxy variable identification of firm productivity in the presence of productivity-modifying learning and spillovers, which facilitates a unified internally consistent analysis of the spillover effects among firms. Contrary to the popular two-step empirical approach, ours does not postulate contradictory assumptions about firm productivity across the estimation steps. Instead, we explicitly accommodate cross-sectional dependence in productivity induced by spillovers, which facilitates identification of both the productivity and spillover effects simultaneously. We apply our model to study cross-firm spillovers in China's electric machinery manufacturing, with a particular focus on productivity effects of inbound FDI.

A linear two-dimensional mathematical model for thin two-layer plates with partial shear interaction, with a view towards application to laminated glass

This work presents a consistent derivation, from three-dimensional linear elasticity, of a two-dimensional mathematical model describing the bending and in-plane stretching behaviours, under a general system of quasi-static distributed loads and prescribed support displacements, of thin two-layer plates with partial shear interaction. This layerwise model is specifically tailored for the requirements posed by the analysis of laminated glass plates commonly used in building structures (consisting of two thin glass layers bonded together by an adhesive interlayer). Our approach, based on Podio-Guidugli’s method of internal constraints, avoids mutually contradictory assumptions (not uncommon in the literature on structural mechanics) and yields a complete two-dimensional characterisation of displacement, strain and stress fields that exactly satisfy the field equations of three-dimensional linear elasticity and the boundary conditions at the end faces. The choice of generalised variables is designed to bring to light the following fundamental conclusion and physical insight: the resulting two-dimensional boundary value problem is a combination of the equations of Kirchhoff and Mindlin plates (with specified rigidities).Two examples illustrate the application of the proposed model: (i) the cylindrical bending of plate strips and (ii) a family of problems with Navier-type analytical solution. The solutions exhibit continuity across the whole range of zero, partial and full interaction between the layers. Moreover, the Navier-type solutions are consistently in close agreement with the results of three-dimensional finite element analyses. On the contrary, analogous results previously reported in the literature exhibit considerable deviations. An explanation for these discrepancies is discussed in detail.

Measuring memory is harder than you think: How to avoid problematic measurement practices in memory research.

We argue that critical areas of memory research rely on problematic measurement practices and provide concrete suggestions to improve the situation. In particular, we highlight the prevalence of memory studies that use tasks (like the "old/new" task: "have you seen this item before? yes/no") where quantifying performance is deeply dependent on counterfactual reasoning that depends on the (unknowable) distribution of underlying memory signals. As a result of this difficulty, different literatures in memory research (e.g., visual working memory, eyewitness identification, picture memory, etc.) have settled on a variety of fundamentally different metrics to get performance measures from such tasks (e.g., A', corrected hit rate, percent correct, d', diagnosticity ratios, K values, etc.), even though these metrics make different, contradictory assumptions about the distribution of latent memory signals, and even though all of their assumptions are frequently incorrect. We suggest that in order for the psychology and neuroscience of memory to become a more cumulative, theory-driven science, more attention must be given to measurement issues. We make a concrete suggestion: The default memory task for those simply interested in performance should change from old/new ("did you see this item'?") to two-alternative forced-choice ("which of these two items did you see?"). In situations where old/new variants are preferred (e.g., eyewitness identification; theoretical investigations of the nature of memory signals), receiver operating characteristic (ROC) analysis should be performed rather than a binary old/new task.

Telomeres in ecology and evolution: A review and classification of hypotheses.

Research on telomeres in the fields of ecology and evolution has been rapidly expanding over the last two decades. This has resulted in the formulation of a multitude of, often name-given, hypotheses related to the associations between telomeres and life-history traits or fitness-facilitating processes (and the mechanisms underlying them). However, the differences (or similarities) between the various hypotheses, which can originate from different research fields, are often not obvious. Our aim here is therefore to give an overview of the hypotheses that are of interest in ecology and evolution and to provide two frameworks that help discriminate among them. We group the hypotheses (i) based on their association with different research questions, and (ii) using a hierarchical approach that builds on the assumptions they make, such as about causality of telomere length/shortening and/or the proposed functional consequences of telomere shortening on organism performance. Both our frameworks show that there exist parallel lines of thoughts in different research fields. Moreover, they also clearly illustrate that there are in many cases competing hypotheses within clusters, and that some of these even have contradictory assumptions and/or predictions. We also touch upon two topics in telomere research that would benefit from further conceptualization. This review should help researchers, both those familiar with and those new to the subject, to identify future avenues of research.

Two Kinds of Postracialism

ABSTRACT Philosophers who work on race and racism have been reluctant to embrace the notion that the United States is, or will soon be, a postracial society. For many, this view is refuted by a wealth of evidence that racism persists in many forms and that race continues to have a significant impact on one's life chances. Nevertheless, some critics of postracialism have refused to reject it in principle or have exempted a particular variety of it from their critiques. This essay attempts to show that the ideal of a postracial society is actually a combination of two contradictory tendencies, each defined by its temporality. Distinguishing these tendencies allows us to see that there are two fundamentally different types of postracialism with contradictory assumptions and conflicting priorities.

On the Paraconsistent Logic CG′3

Paraconsistent logical systems are well-known reasoning frameworks aimed to infer new facts or properties under contradictory assumptions. Applications of these systems are well known in wide range of computer science domains. In this article, we study the paraconsistent logic CG ′ 3 , which can be viewed as an extension of the logic G ′ 3 . CG ′ 3 is also 3 -valued, but with two designated values. Main results can be summarized as follows: a Hilbert-type axiomatization, based on Kalmár’s approach; and a new notion of validity, based on also novel Kripke semantics.

The Influence of Employee Competency in Small and Medium Business Brazil and Brics and Jair Bolsonaro’s 1st Year of Presidency

This study aims to look at employee competency with job satisfaction as an intervening variable at small and medium business (SMB) by consdring the Brazil politics. The political stage in Brazil changed course towards the “right” on 1 January 2019 when the anti-globalist former army officer Jair Bolsonaro was inaugurated as the 38th President of the Republic. That was an abrupt change of ideologies for a country leaded by the “left” (Workers’ Party) in the last 13 years. Scholars made contradictory assumptions about the future of BRICS: one of the most significant economic organisations on the international arena nowadays, within the new Brazilian background. In the beginning of 2019 the opportunity for Braxit was not excluded, although there was no immediate call for it. However, the most common opinion came from pragmatists like N. Muhandiram: they affirmed that the union would keep functioning but it would meet multiple challenges. This article gives an answer to the question why the “right” turn in Brazil affects the relations between the biggest Latin American democracy and BRICS.

New results of fuzzy implications satisfying I(x,I(y,z))=I(I(x,y),I(x,z))

Cruz et al. (2018) [10] investigated the fuzzy generalization of Frege's Law: x→(y→z)≡(x→y)→(x→z), i.e., I(x,I(y,z))=I(I(x,y),I(x,z)), which is called generalized Frege's Law. They showed conditions such that the generalized Frege's Law holds for (S,N)-implications (R-, QL-, D-, (T,N)-, H-, respectively).In this paper, firstly, a new necessary condition such that the generalized Frege's Law holds is given: NI, the natural negation of I, is not continuous or has no fixed point. Based on this result, some propositions in [10] with contradictory assumptions are pointed out, and a correction is given. Secondly, new solutions of the equation I(x,I(y,z))=I(I(x,y),I(x,z)) in (S,N)-implications are given. Finally, the necessary and sufficient conditions under which the generalized Frege's Law holds for the (U,N)-implications (f-, g-, T-Power based implications, respectively) are studied.

Resolving the mystery of the concentration-dependence of amphoteric dopant diffusion in III-V semiconductors

Amphoteric dopants, such as silicon, exhibit a concentration-dependent diffusivity in III-V compounds characterized by a low to negligible diffusion at low dopant concentrations, which increases by orders of magnitude at high concentrations. The reason for this anomalous and non-intuitive diffusivity has largely remained a mystery. Leading models from literature, built to explain existing experimental results, make contradictory assumptions on the nature of the diffusing species, based only on thermodynamic considerations. In this work, we perform ab initio calculations to characterize the kinetics of dopant diffusion in III-V materials revealing how the nature of the primary diffusing species changes with concentration. We use these results to derive a new analytical model which fits historical, as well as more recent, experimental data on Si diffusion in GaAs and In0.57Ga0.43As. This work provides a fundamentals-based understanding of Si diffusion in III-V alloys as well as a new predictive analysis tool while showcasing a mutiscale approach of solving diffusion problems. We hope this work will help guide the design of the next generation of III-V based electronic and photonic devices.

Environmental assessments of biological treatments of biowaste in life cycle perspective: A critical review.

Municipal biowaste is a major environmental issue. Life-cycle assessment is a valuable tool to assess recycling options, and anaerobic digestion and composting have performed adequately. However, reviews indicate several discrepancies between studies. Thus, we critically review 25 life-cycle assessments of the composting and anaerobic digestion of municipal biowaste. Our objective is to identify decisive factors, methodological gaps and processes that affect environmental performance. We generally identified methodological gaps in expanding systems borders. In energy systems, the replaced energy source did not consider power generation or dynamic regulation. All studies adopted mixed energy sources or marginal approaches. Agroecosystems included the carbon sequestration potential and compensation for the production of synthetic fertilizers only. A limited range of scientifically proven benefits of compost use has been reported. In general, studies provided a limited account of the effects of use on land emissions, but contradictory assumptions emerged, mainly in modelling synthetic fertilizer compensation. Only three studies compensated direct emissions from the use of synthetic fertilizers, and none included indirect emissions. Further studies should include an analysis of the additional benefits of compost use, compensate for the effects of emissions from synthetic fertilizer use on land and mix attributional and consequential approaches in energy system expansion.

Paradygmatyczne punkty widzenia nauk o bezpieczeństwie

Kuhn’s concept of paradigm refers to the distinction between mature and pre-paradigmatic science. Different approaches may compete in the latter stage. In security sciences, there is a discussion on the search for paradigms, which can mean a consensus of views within one discipline or contradictory assumptions. The discussion is a consequence of the evolution of this relatively recently emerged discipline and leads to the definition of its specificity. The paper presents various approaches to the paradigm proposed by representatives of security research in the broad sense of the term, which lead to a multi-paradigm shift. The research problem is an attempt to answer the question whether the presented points of view are the basis for formulating coherent assumptions of paradigms on the grounds of safety sciences and which scientists propose paradigms in this scientific discipline. Establishing one common approach as the most effective one will mean that a paradigm of safety science will emerge. Finally, the concept of personal security was proposed in terms of the system paradigm.

Men as promoters of change in ECEC? An international overview

ABSTRACT This paper gives an overview of international developments towards gender balance in the ECEC workforce in the last three decades. Research results on the role of male and female ECEC professionals and strategies for recruiting more men are reflected against goals of gender diversity and equality. As the overview shows, attitudes towards male workers and strategies for increasing participation of men are rooted in diverse and often contradictory assumptions about the ‘nature’ of men and women, their role in children’s gendered development, and the relevance of ECEC for gender equality in general. It is concluded that gender-mixed teams in ECEC institutions need gender-conscious reflection and ongoing development of gender-sensitive pedagogy. Moreover, strategies for employing more men in ECEC have to be embedded in a discourse on gender equality in wider society.

The Duplicity of Choice and Empowerment: Disability Rights Diluted in Australia’s Policies on Assistive Technology

The combination of choice as a contested concept and its increasing adoption as a policy principle necessitates a critical analysis of its interpretation within Australia’s reforms to disability services. While choice may appear to be an abstract and flexible principle in policy, its operationalization in practice tends to come with conditions. This paper investigates the interpretation of choice in the National Disability Insurance Scheme (NDIS), via an interpretive policy analysis of assistive technology (AT) provision. Analysis of policy artefacts reveals a diminishing influence of disability rights in favor of an economic discourse, and contradictory assumptions about choice in the implementation of legislation. The language of choice and empowerment masks the relegation of the presumption of capacity to instead perpetuate professional power in determining access to resources by people with disability.

Thermochemistry, Tautomerism, and Thermal Decomposition of 1,5-Diaminotetrazole: A High-Level ab Initio Study.

Thermochemistry, kinetics, and mechanism of thermal decomposition of 1,5-diaminotetrazole (DAT), a widely used "building block" of nitrogen-rich energetic compounds, were studied theoretically at a high and reliable level of theory (viz., using the explicitly correlated CCSD(T)-F12/aug-cc-pVTZ procedure). Quantum chemical calculations provided detailed insight into the thermolysis mechanism of DAT missing in the existing literature. Moreover, several contradictory assumptions on the mechanism and key intermediates of thermolysis were resolved. The unimolecular primary decomposition reactions of the seven isomers of DAT were studied in the gas phase and in the melt using a simplified model of the latter. The two-step reaction of N2 elimination from the diamino tautomer was found to be the primary decomposition process of DAT in the gas phase and melt. The effective Arrhenius parameters of this process were calculated to be E a = 43.4 kcal mol-1 and log( A/s-1) = 15.2 in a good agreement with the experimental values. Contrary to the existing literature data, all other decomposition channels of DAT isomers turned out to be kinetically unimportant. Apart from this, a new primary decomposition channel yielding N2, cyanamide, and 1,1-diazene was found for some H-bonded dimers of DAT. We also determined a reliable and mutually consistent set of thermochemical values for DAT (Δ f H solid0 = 74.5 ± 1.5 kcal·mol-1) by combining theoretically calculated (W1 multilevel procedure along with an isodesmic reaction) gas phase enthalpy of formation (Δ f H gas0 = 100.7 ± 1.0 kcal·mol-1) and experimentally measured sublimation enthalpy (Δ sub H0 = 26.2 ± 0.5 kcal·mol-1).

Reconciling ethical and economic conceptions of value in health policy using the capabilities approach: A qualitative investigation of Non-Invasive Prenatal Testing

When evaluating new morally complex health technologies, policy decision-makers consider a broad range of different evaluations, which may include the technology's clinical effectiveness, cost effectiveness, and social or ethical implications. This type of holistic assessment is challenging, because each of these evaluations may be grounded in different and potentially contradictory assumptions about the technology's value.One such technology where evaluations conflict is Non-Invasive Prenatal Testing (NIPT). Cost-effectiveness evaluations of NIPT often assess NIPT's ability to deliver on goals (i.e preventing the birth of children with disabilities) that social and ethical analyses suggest it should not have. Thus, cost effectiveness analyses frequently contradict social and ethical assessments of NIPT's value.We use the case of NIPT to explore how economic evaluations using a capabilities approach may be able to capture a broader, more ethical view of the value of NIPT. The capabilities approach is an evaluative framework which bases wellbeing assessments on a person's abilities, rather than their expressed preferences. It is linked to extra-welfarist approaches in health economic assessment. Beginning with Nussbaum's capability framework, we conducted a directed qualitative content analysis of interview data collected in 2014 from 27 Canadian women with personal experience of NIPT. We found that eight of Nussbaum's ten capabilities related to options, states, or choices that women valued in the context of NIPT, and identified one new capability. Our findings suggest that women value NIPT for its ability to provide more and different choices in the prenatal care pathway, and that a capabilities approach can indeed capture the value of NIPT in a way that goes beyond measuring health outcomes of ambiguous social and ethical value. More broadly, the capabilities approach may serve to resolve contradictions between ethical and economic evaluations of health technologies, and contribute to extra-welfarist approaches in the assessment of morally complex health technologies.

SUPECA kinetics for scaling redox reactions in networks of mixed substrates and consumers and an example application to aerobic soil respiration

Abstract. Several land biogeochemical models used for studying carbon–climate feedbacks have begun explicitly representing microbial dynamics. However, to our knowledge, there has been no theoretical work on how to achieve a consistent scaling of the complex biogeochemical reactions from microbial individuals to populations, communities, and interactions with plants and mineral soils. We focus here on developing a mathematical formulation of the substrate–consumer relationships for consumer-mediated redox reactions of the form A + BE→ products, where products could be, e.g., microbial biomass or bioproducts. Under the quasi-steady-state approximation, these substrate–consumer relationships can be formulated as the computationally difficult full equilibrium chemistry problem or approximated analytically with the dual Monod (DM) or synthesizing unit (SU) kinetics. We find that DM kinetics is scaling inconsistently for reaction networks because (1) substrate limitations are not considered, (2) contradictory assumptions are made regarding the substrate processing rate when transitioning from single- to multi-substrate redox reactions, and (3) the product generation rate cannot be scaled from one to multiple substrates. In contrast, SU kinetics consistently scales the product generation rate from one to multiple substrates but predicts unrealistic results as consumer abundances reach large values with respect to their substrates. We attribute this deficit to SU's failure to incorporate substrate limitation in its derivation. To address these issues, we propose SUPECA (SU plus the equilibrium chemistry approximation – ECA) kinetics, which consistently imposes substrate and consumer mass balance constraints. We show that SUPECA kinetics satisfies the partition principle, i.e., scaling invariance across a network of an arbitrary number of reactions (e.g., as in Newton's law of motion and Dalton's law of partial pressures). We tested SUPECA kinetics with the equilibrium chemistry solution for some simple problems and found SUPECA outperformed SU kinetics. As an example application, we show that a steady-state SUPECA-based approach predicted an aerobic soil respiration moisture response function that agreed well with laboratory observations. We conclude that, as an extension to SU and ECA kinetics, SUPECA provides a robust mathematical representation of complex soil substrate–consumer interactions and can be applied to improve Earth system model (ESM) land models.