The debate between ΛCDM and MOND is often cast in terms of competing gravitational theories. However, recent philosophical discussion suggests that the ΛCDM–MOND debate demonstrates the challenges of multiscale modeling in the context of cosmological scales. I extend this discussion and explore what happens when the debate is thought to be about modeling rather than about theory, offering a model-focused interpretation of the ΛCDM–MOND debate. This analysis shows how a model-focused interpretation of the debate provides a better (...) understanding of challenges asso- ciated with extension to a different scale or domain, which are tied to commitments about explanatory fit. (shrink)

The \CDM cosmological model is remarkable: with just six parameters it describes the evolution of the Universe from a very early time when all structures were quantum fluctuations on subatomic scales to the present, and it is consistent with a wealth of high-precision data, both laboratory measurements and astronomical observations. However, the foundation of \CDM involves physics beyond the standard model of particle physics: particle dark matter, dark energy and cosmic inflation. Until this ‘new physics’ is clarified, \CDM is at (...) best incomplete and at worst a phenomenological construct that accommodates the data. I discuss the path forward, which involves both discovery and disruption, some grand challenges and finally the limits of scientific cosmology. (shrink)

In the paper we show that modern cosmology has a status of effective theory of the Universe similarly to the standard models in particle physics. We illustrate that the source of such a point of view is the fact that the complete theory of the Universe (TOE) should be complicated enough to derive observables. The role of epistemological emergence in the context of cosmological models (Cold Dark Matter vs. Lambda Cold Dark Matter) is also investigated. We demonstrate that while the (...) effective theories of the Universe are not conceptually simple and elegant, their strength lies in the predictive accuracy and data fitting required for the model testing. (shrink)

While $$\Lambda $$ Λ CDM has emerged as the standard model of cosmology, a small group of physicists defends modified newtonian dynamics (MOND) as an alternative view on cosmology. Exponents of MOND have employed a broad, at times explicitly philosophical, conceptual perspective in arguing their case. This paper offers reasons why that MONDian defense has been ineffective. First, we argue that the defense is ineffective according to Popperian or Lakatosian views–ostensibly the preferred philosophical views on theory assessment of proponents of (...) MOND. Second, we argue that the defense of MOND can instead best be reconstructed as an instance of meta-empirical theory assessment. The formal employment of meta-empirical assessment by MONDians is unconvincing, however, because it lacks a sufficient epistemic foundation. Specifically, the MONDian No Alternatives Argument relies on falsifiability or explanation conditions that lack epistemic relevance, while the argument from Unexpected Explanatory Success fails since there is a known alternative to MOND. In the last part of the paper, we draw some lessons for applications of meta-empirical assessment more generally. (shrink)

Cosmologists take the $\Lambda$CDM model to be a permanent contribution to our knowledge of the universe, based on the success of precision cosmology. Consistent, independent determinations of the parameters in this model encourage physicists to take it seriously. This stance incurs an obligation to resolve any discrepancies by reanalyzing measurements or adding further complexity. Recent observations in cosmology indicate a tension between “local” and “global” determinations of the Hubble constant. Here I argue that this tension illustrates one of the benefits (...) of taking the model seriously and consider the challenges to making a case for the permanence of $\Lambda$CDM. (shrink)

In recent years, apparently the Big Bang as described by the Lambda CDM-Standard Model Cosmology has become widely accepted by majority of physics and cosmology communities. Even some people have concluded that it has no serious alternative in horizon. Is that true? First, as we argued elsewhere, Big Bang story relies on singularity. In other words, when we are able to describe the observed data without invoking singularity, then Big Bang model is no longer required. Therefore, here we explore a (...) few alternative stories other than Big Bang story, which most cosmologists believe it is the nearest to Biblical account of creation. We would argue that re-reading of Genesis 1:2 will lead us to another viable story, albeit the alternative has not been developed rigorously as LCDM theories. We also briefly discuss a fluid Maxwell equations of Prof. Tsutomu Kambe based on vortex sound theory. (shrink)

The standard model of cosmology is acclaimed in physics as accurate, robust, well-tested, our best scientific theory of the cosmos, but it has had serious anomalies for a while, including the Hubble tension, anomalous galaxies, and the completely unexplained nature of dark energy and dark matter. And lurking behind it all is the lack of a unified theory: General Relativity (GR) and quantum mechanics (QM) are inconsistent. Now startling new observations by the James Webb Space Telescope (JWST) in 2022 of (...) the early universe present the strongest challenge yet to the standard model, and whispers have started that this shows there is something wrong with the fundamental theory, General Relativity itself. This would be a crisis for cosmology. But haven’t they tested this theory already, and shown it is correct? How could it turn out wrong at this late stage? Here we compare the standard cosmology with an alternative fundamental theory, that has a strikingly different overall cosmological behavior: a simple cyclic expansion function. It is simple and deterministic. There are only two or three general parameters. The interesting result is that this alternative cosmology: (A) closely matches the expansion observed and modelled through the CDM standard model, now going back to red-shifts of 5-15; and (B) it also predicts unexpected early galaxy formation now being reported by the JWST. The point here is not to try to prove this alternative theory however, but rather show how it compares to the conventional cosmology. This show us clearly how weak the empirical evidence for the standard model really is against a counterfactual fundamental theory. Some results established in science are robust against theory change, but we find the standard cosmological model and the implications drawn from it are not robust at all. (shrink)

Cognitive diagnostic models show great promise in language assessment for providing rich diagnostic information. The lack of a full understanding of second language listening subskills made model selection difficult. In search of optimal CDM that could provide a better understanding of L2 listening subskills and facilitate accurate classification, this study carried a two-layer model selection. At the test level, A-CDM, LLM, and R-RUM had an acceptable and comparable model fit, suggesting mixed inter-attribute relationships of L2 listening subskills. At the item (...) level, Mixed-CDMs were selected and confirmed the existence of mixed relationships. Mixed-CDMs had better model and person fit than G-DNIA. In addition to statistical approaches, the content analysis provided theoretical evidence to confirm and amend the item-level CDMs. It was found that semantic completeness pertaining to the attributes and item features may influence the attribute relationships. Inexplicable attribute conflicts could be a signal of suboptimal model choice. Sample size and the number of multi-attribute items should be taken into account in L2 listening cognitive diagnostic modeling studies. This study provides useful insights into the model selection and the underlying cognitive process for L2 listening tests. (shrink)

According to the standard interpretation of Einstein’s field equations, gravity consists of mass-energy curving spacetime, and an additional physical force or entity—denoted by Λ (the ‘cosmological constant’)—is responsible for the Universe’s metric-expansion. Although General Relativity’s direct predictions have been systematically confirmed, the dominant cosmological model thought to follow from it—the ΛCDM (Lambda cold dark matter) model of the Universe’s history and composition—faces considerable challenges, including various observational anomalies and experimental failures to detect dark matter, dark energy, or inflation-field candidates. (...) This paper shows that Einstein’s Equivalence Principle entails two possible physical interpretations of General Relativity’s field equations. Although the field equations facially appear to support the standard interpretation—that gravity consists of mass-energy curving spacetime—the field equations can be equivalently understood as holding that gravitational effects instead result from mass-energy accelerating the metric-expansion of a second-order spacetime fabric superimposed upon an absolute, first-order Euclidean space, resulting in the observational appearance of spacetime curvature. This alternative interpretation of relativity is shown to be empirically equivalent to the standard interpretation of relativity, albeit with a changing value for Λ (which is similar to how Λ is understood in the conception of Λ as ‘quintessence’, but in this case takes Λ to be gravity). The reconceptualization is then shown to potentially resolve major observational anomalies for the ΛCDM model, including recent observations conflicting with ΛCDM predictions, as well as failures to directly detect dark matter, dark energy, and inflation field/particle candidates. (shrink)

In the framework of contemporary cosmology, the age-old aspiration to inquire the outer limits of the universe translates into our effort to observe the initial stages of cosmic history. Thanks to a fortunate combination of astronomical circumstances, and pushing mm-wave technology to its limits, today we are able to image the early universe in great detail, back at a time when cosmic age was only 0.0027% of its present value. The state of the art in the field has been set (...) by the ESA Planck mission, launched in 2009, dedicated to precision measurements of the cosmic microwave background. Planck observed the full sky for 4 years in a wide frequency range, reaching μK sensitivity both in temperature and polarization. The latest results, published by the Planck Collaboration in 2018, are in exquisite agreement with the simplest 6-parameter ΛCDM model and constrain the main cosmological parameters with percent-level accuracy. Furthermore, the Planck data yield insight on the very early universe, opening the way to a new generation of experiments searching for the possible signatures of primordial gravitational waves in the CMB polarization pattern. (shrink)

One purpose of cognitive diagnostic model is designed to make inferences about unobserved latent classes based on observed item responses. A heuristic for test construction based on the CDM information index proposed by Henson and Douglas has a far-reaching impact, but there are still many shortcomings. He and other researchers had also proposed new methods to improve or overcome the inherent shortcomings of the CDI test assembly method. In this study, one test assembly method of maximizing the minimum inter-class distance (...) is proposed by using mixed-integer linear programming, which aims to overcome the shortcomings that the CDI method is limited to summarize the discriminating power of each item into a single CDI index while neglecting the discriminating power for each pair of latent classes. The simulation results show that compared with the CDI test assembly and random test assembly, the new test assembly method performs well and has the highest accuracy rate in terms of pattern and attributes correct classification rates. Although the accuracy rate of the new method is not very high under item constraints, it is still higher than the CDI test assembly with the same constraints. (shrink)

In spite of successful tests, the standard cosmological model, the $$\varLambda$$ CDM model, possesses the most problematic concept: the initial singularity, also known as the big bang. In this paper—by adopting the Kantian difference between to think of an object and to cognize an object—it is proposed a degree of scientificity using fuzzy sets. Thus, the notion of initial singularity will not be conceived of as a scientific issue because it does not belong to the fuzzy set of what is (...) known. Indeed, the problematic concept of singularity is some sort of what Kant called the noumenon, but science, on the other hand, is constructed in the phenomenon. By applying the fuzzy degree of scientificity in cosmological models, one concludes that cosmologies with a contraction phase before the current expansion phase are potentially more scientific than the standard model. At the end of this article, it is shown that Kant’s first antinomy of pure reason indicates a limit to our cosmological models. (shrink)

According to the standard model of cosmology, Λ\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\Lambda $$\end{document}CDM, the mass-energy budget of the current stage of the universe is not dominated by the luminous matter that we are familiar with, but instead by some form of dark matter (and dark energy). It is thus tempting to adopt scientific realism about dark matter. However, there are barely any constraints on the myriad of possible properties of this entity—it is not even certain (...) that it is a form of matter. In light of this underdetermination I advocate caution: we should not (yet) be dark matter realists. The “not(-yet)-realism” that I have in mind is different from Hacking’s (Philos Sci 56 (4), 555–581, 1989) anti-realism, in that it is semantic rather than epistemological. It also differs from the semantic anti-realism of logical empiricism, in that it is naturalistic, such that it may only be temporary and does not automatically apply to all other unobservables (or even just to all other astronomical unobservables, as with Hacking’s anti-realism). The argument is illustrated with the analogy of the much longer history of the concept of a gene, as the current state of the concept of dark matter resembles in some relevant ways that of the early concept of genes. (shrink)

We review the observational foundations of the ΛCDMΛCDM model, considered by most cosmologists as the standard model of cosmology. The Cosmological Principle, a key assumption of the model is shown to be verified with increasing accuracy. The fact that the Universe seems to have expanded from a hot and dense past is supported by many independent probes . The explosion of detailed observations in the last few decades has allowed for precise measurements of the cosmological parameters within Friedman–Lemaître–Robertson–Walker cosmologies leading (...) to the ΛCDMΛCDM model: an apparently flat Universe, dominated by a cosmological constant, whose matter component is dominantly dark. We describe and discuss the various observational probes that led to this conclusion and conclude that the ΛCDMΛCDM model, although leaving a number of open questions concerning the deep nature of the constituents of the Universe, provides the best theoretical framework to explain the observations. (shrink)

The main foundations of the standard \CDM model of cosmology are that: the redshifts of the galaxies are due to the expansion of the Universe plus peculiar motions; the cosmic microwave background radiation and its anisotropies derive from the high energy primordial Universe when matter and radiation became decoupled; the abundance pattern of the light elements is explained in terms of primordial nucleosynthesis; and the formation and evolution of galaxies can be explained only in terms of gravitation within a inflation (...) + dark matter + dark energy scenario. Numerous tests have been carried out on these ideas and, although the standard model works pretty well in fitting many observations, there are also many data that present apparent caveats to be understood with it. In this paper, I offer a review of these tests and problems, as well as some examples of alternative models. (shrink)

The purpose of cognitive diagnostic modeling is to classify students' latent attribute profiles using their responses to the diagnostic assessment. In recent years, each diagnostic classification model makes different assumptions about the relationship between a student's response pattern and attribute profile. The previous research studies showed that the inappropriate DCMs and inaccurate Q-matrix impact diagnostic classification accuracy. Artificial Neural Networks have been proposed as a promising approach to convert a pattern of item responses into a diagnostic classification in some research (...) studies. However, the ANNs methods produced very unstable and unappreciated estimation unless a great deal of care was taken. In this research, we combined ANNs with two typical DCMs, the deterministic-input, noisy, “and” gate model and the deterministic-inputs, noisy, “or” gate model, within a semi-supervised learning framework to achieve a robust and accurate classification. In both simulated study and real data study, the experimental results showed that the proposed method could achieve appreciated performance across different test conditions, especially when the diagnostic quality of assessment was not high and the Q-matrix contained misspecified elements. This research study is the first time of applying the thinking of semi-supervised learning into CDM. Also, we used the validating test to choose the appropriate parameters for the ANNs instead of using typical statistical criteria. (shrink)

I try to revive, and possibly reconcile, a debate started a few years ago, about the relative roles of a bare cosmological constant and of a vacuum energy, by taking the attitude to try to get the most from the physics now available as established. I notice that the bare cosmological constant of the Einstein equations, which is there ever since GR emerged, is actually constrained (if not measured) indirectly combining the effective cosmological constant observed now, as given by (...) class='Hi'>ΛCDM Precision Cosmology, with the cumulative vacuum contribution of the particles of the Standard Model, SM. This comes out when the vacuum energy is regularized, as given by many Authors, still within well established Quantum Field Theory, QFT, but without violating Lorentz invariance. The fine tuning, implied by the compensation to a small positive value of the two large contributions, could be seen as offered by Nature, which provides one more fundamental constant, the bare Lambda. The possibility is then discussed of constraining (measuring) directly such a bare cosmological constant by the features of primordial gravitational wave signals coming from epoch’s precedent to the creation of particles. I comment on possibilities that would be lethal, that is if the vacuum does not gravitate. This last issue is often raised, and I discuss the current situation about. Finally a hint is briefly discussed for a possible “bare Lambda inflation” process. (shrink)

This paper explores whether the Clean Development Mechanism (CDM), a flexibility mechanism under the Kyoto Protocol, has contributed to poverty alleviation in countries that host CDM projects. We argue that the CDM should deliver pro-poor benefits to the communities in which projects are established, since poverty alleviation is integral to sustainable development, which is one of the main purposes of the CDM. After briefly discussing the background of the CDM, we discuss assessment difficulties to which research is prone when evaluating (...) CDM projects for alleged sustainable development contributions. Section 4 brings together and analyses available empirical research on the pro-poor benefits the CDM purportedly delivers to host country communities, concluding that the CDM has failed to deliver poverty alleviation. Therefore, without attempting to be exhaustive, we suggest policy reforms that aim to redirect the CDM to those most in need of assistance. (shrink)

Tetrahymena has been used as a model cell system in many studies of morphogenesis, conjugation, gene mapping, cell division and growth kinetics. In this article, we consider some advances which have resulted from the successful development of a chemically defined medium (CDM), and how subsequent work has extended the contribution that this organism has made to our understanding of different aspects of growth, nutrition, cell cycle control, cytokinesis and intercellular signalling. Finally, we discuss the considerable potential that has arisen for (...) the biotechnological exploitation of this big and rapidly growing eukaryotic cell. (shrink)

This paper examines the ethical implications of the Clean Development Mechanism, the United Nation’s climate change initiative that provides incentives to countries and firms in developed countries to motivate investments in greenhouse gas reduction projects in developing countries. Using the tenets of agency theory, we present a solid waste management project in El Salvador as an illustrative example of how the CDM can produce a disproportionately high social cost for the most marginalized populations in the developing world. We suggest that (...) the UN needs to reformulate the CDM so that it more effectively aligns the divergent goals of multiple actors and upholds the UN’s principles for sustainable development, including ethical firm-level behavior. By providing incentives for environmental, economic, and social value creation, the CDM would not only promote ethical norms for profit-seeking firms that participate in the program but also reinforce the UN’s twin pro-poor and environmental objectives. (shrink)

The high precision attained by cosmological data in the last few years has increased the interest in exact solutions. Analytic expressions for solutions in the Standard Model are presented here for all combinations of Λ = 0, Λ ≠ 0, κ = 0, and κ ≠ 0, in the presence and absence of radiation and nonrelativistic matter. The most complete case (here called the ΛγCDM Model) has Λ ≠ 0, κ ≠ 0, and supposes the presence of radiation and dust. (...) It exhibits clearly the recent onset of acceleration. The treatment includes particular models of interest such as the ΛCDM Model (which includes the cosmological constant plus cold dark matter as source constituents). (shrink)

A central component to scientific practice is the construction and use of scientific models. Scientists believe that the success of a model justifies making claims that go beyond the model itself. However, philosophical analysis of models suggests that drawing inferences about the world from successful models is more complex. In this dissertation I develop a framework that can help disentangle the related strands of evaluation of model success, model extendibility, and the ability to draw ampliative inferences about the world from (...) models. I present and critically assess two leading accounts of model assessment, arguing that neither is sufficient to provide a complete understanding of model evaluation. I introduce a more powerful framework incorporating elements of the two views, which can help answer these three questions: What is the target of evaluation in model assessment? How does that evaluation proceed? What licenses us in making inferences about the real world, based on the evaluation of our models as successful? The framework identifies two distinct targets of model evaluation: representational similarity between the model and target system, and the adequacy of the model as a tool to answer questions. Both assessments must be relativized to a purpose, of which there are three general kinds: descriptive, predictive, and explanatory. These purposes differ in the way they inform the similarity relation, which is relevant for the similarity assessment, and the output they produce, which is relevant for the adequacy assessment. Any model can be assessed relative to any purpose, however a model encodes certain decisions made during the model’s construction, which impact its ability to be applied to a new purpose or new domain. My framework shows that extending a model, and drawing inferences from it, depends on its representational similarity. I apply this framework to several examples taken from astrophysics showing in detail how it can help illuminate the structure of the models, as well as make the justification for inferences made from them clear. The final chapter is a detailed analysis of a contemporary debate surrounding the use of models in astrophysics, between proponents of MOND and the standard ΛCDM model. (shrink)

The study hypothesizes that the environmental, social, and governance of the host country have a significant effect on clean development mechanism implementation. As CDM incorporates sustainable development as one of the objectives for the green transition, many countries endeavor to adopt and implement CDM as their cleaner production method. Based on the institutional theory, the study aims to investigate the mechanism by which the institutional process of each ESG pillar makes an opportunity for a host country and to see how (...) such country-specific factors influence the implementation of CDM projects. A county-year unbalanced sample drawn from World Bank and multinational CDM project data was analyzed using panel logistic and Poisson regression. Panel regression results show that high-energy intensity and low renewable electricity output as an environmental pillar positively affect CDM implementation. Unemployment and undernourishment as a social pillar positively affect CDM whereas low government effectiveness and the high rule of law positively affect CDM. In the results of zero-inflated Poisson regression, the direction of government effectiveness was upturned. The findings have broadened and deepened the ESG pillar based on the institutional theory and emphasized sustainable development rather than economic outputs. (shrink)

Cognitive diagnostic assessment has been developed rapidly to provide fine-grained diagnostic feedback on students’ subskills and to provide insights on remedial instructions in specific domains. To date, most cognitive diagnostic studies on reading tests have focused on retrofitting a single booklet from a large-scale assessment. Critical issues in CDA involve the scarcity of research to develop diagnostic tests and the lack of reliability and validity evidence. This study explored the development and validation of the Diagnostic Chinese Reading Comprehension Assessment for (...) primary students under the CDA framework. Reading attributes were synthesized based on a literature review, the national curriculum criteria, the results of expert panel judgments, and student think-aloud protocols. Then, the tentative attributes were used to construct three booklets of reading comprehension items for 2–6 graders at three key stages. The assessment was administered to a large population of students in grades 2–6 from 20 schools in a district of Changchun City, China. Q-matrices were compared and refined using the model-data fit and an empirical validation procedure, and five representative cognitive diagnostic models were compared for optimal performance. The fit indices suggested that a six-attribute structure and the G-DINA model were best fitted for the reading comprehension assessment. In addition, diagnostic reliability, construct, internal and external validity results were provided, supporting CDM classifications as reliable, accurate, and useful. Such diagnostic information could be utilized by students, teachers, and administrators of reading programs and instructions. (shrink)

As of September 2005, the co-founders of Waste Concern, an organisation dedicated to improving waste recycling in Bangladesh, are considering making a change to their model in order to get approval from the municipal government for a large-scale composting site. Since its inception in 1995, Waste Concern has followed a decentralised composting model whereby each composting site is a small-scale operation processing 3 tons of organic waste per day. In this model, they have relied on land and waste supply from (...) the Dhaka City Council (DCC) municipal government. Now, they are working with Dutch-based World Wide Recycling BV (WWR) to set up a 700-ton per day composting plant, which will enable them to earn tradable certificates for US$11 per ton of reduced methane gas, making it the first in the world to garner credits through composting waste under the United Nations Clean Development Mechanism (CDM). To launch the composting site, they face the hurdle of getting DCC’s approval. They have three alternatives: (1) follow through with the original plan whereby the municipality would supply both the land and waste, which entails waiting for DCC’s approval; (2) purchase the land for the composting site and rely on the municipality for a waste supply; or, (3) purchase the land and take on the responsibility of waste collection themselves. In their considerations, they need to weigh the financial and social aspects and determine an appropriate structure for their organisation. (shrink)

As of September 2005, the co-founders of Waste Concern, an organisation dedicated to improving waste recycling in Bangladesh, are considering making a change to their model in order to get approval from the municipal government for a large-scale composting site. Since its inception in 1995, Waste Concern has followed a decentralised composting model whereby each composting site is a small-scale operation processing 3 tons of organic waste per day. In this model, they have relied on land and waste supply from (...) the Dhaka City Council (DCC) municipal government. Now, they are working with Dutch-based World Wide Recycling BV (WWR) to set up a 700-ton per day composting plant, which will enable them to earn tradable certificates for US$11 per ton of reduced methane gas, making it the first in the world to garner credits through composting waste under the United Nations Clean Development Mechanism (CDM). To launch the composting site, they face the hurdle of getting DCC’s approval. They have three alternatives: (1) follow through with the original plan whereby the municipality would supply both the land and waste, which entails waiting for DCC’s approval; (2) purchase the land for the composting site and rely on the municipality for a waste supply; or, (3) purchase the land and take on the responsibility of waste collection themselves. In their considerations, they need to weigh the financial and social aspects and determine an appropriate structure for their organisation. (shrink)

This richly illustrated book discusses the ways in which astronomy expanded after 1945 from a modest discipline to a robust and modern science. It begins with an introduction to the state of astronomy in 1945 before recounting how in the following years, initial observations were made in hitherto unexplored ranges of wavelengths, such as X-radiation, infrared radiation and radio waves. These led to the serendipitous discovery of more than a dozen new phenomena, including quasars and neutron stars, that each triggered (...) a new area of research. The book goes on to discuss how after 1985, the further, systematic exploration of the earlier discoveries led to long-term planning and the construction of new, large telescopes on Earth and in Space. Key scientific highlights described in the text are the detection of exoplanets, the unexpected discovery of the accelerated expansion of the Universe, a generally accepted model for the large-scale properties of the Universe and the ΛCDM theory that explains how the galaxies and stars of the present Universe were formed from minute irregularities in the homogenous gas that filled the early Universe. All these major scientific achievements came at a price, namely the need to introduce two new phenomena that are as yet unexplained by physics: inflation and dark energy. Probably the deepest unsolved question has to be: Why did all of this start with a Big Bang? (shrink)

Cognitive diagnosis models allow classifying respondents into a set of discrete attribute profiles. The internal structure of the test is determined in a Q-matrix, whose correct specification is necessary to achieve an accurate attribute profile classification. Several empirical Q-matrix estimation and validation methods have been proposed with the aim of providing well-specified Q-matrices. However, these methods require the number of attributes to be set in advance. No systematic studies about CDMs dimensionality assessment have been conducted, which contrasts with the vast (...) existing literature for the factor analysis framework. To address this gap, the present study evaluates the performance of several dimensionality assessment methods from the factor analysis literature in determining the number of attributes in the context of CDMs. The explored methods were parallel analysis, minimum average partial, very simple structure, DETECT, empirical Kaiser criterion, exploratory graph analysis, and a machine learning factor forest model. Additionally, a model comparison approach was considered, which consists in comparing the model-fit of empirically estimated Q-matrices. The performance of these methods was assessed by means of a comprehensive simulation study that included different generating number of attributes, item qualities, sample sizes, ratios of the number of items to attribute, correlations among the attributes, attributes thresholds, and generating CDM. Results showed that parallel analysis, factor forest model, and model comparison are suitable alternatives to determine the number of attributes in CDM applications, with an overall percentage of correct estimates above 76% of the conditions. The accuracy increased to 97% when these three methods agreed on the number of attributes. In short, the present study supports the use of three methods in assessing the dimensionality of CDMs. This will allow to test the assumption of correct dimensionality present in the Q-matrix estimation and validation methods, as well as to gather evidence of validity to support the use of the scores obtained with these models. The findings of this study are illustrated using real data from an intelligence test to provide guidelines for assessing the dimensionality of CDM data in applied settings. (shrink)

Pokazujemy, że kosmologia współczesna posiada cechy efektywnej teorii fizycznej podobnej do standardowego modelu cząstek elementarnych. Obecnie mamy do czynienia z konstytuowaniem się tzw. standardowego modelu kosmologicznego. W pracy wskazujemy na cechy charakterystyczne takiego modelu, który jest modelem kosmologicznym o maksymalnej symetrii (jednorodność i izotropowość przestrzenna) wypełnionego materią barionową i ciemną materią oraz ciemną energią (ze stałą kosmologiczną). Model ten jest nazywany modelem standardowym LCDM (Lambda - Cold - Dark Matter model) i jest rozwiązaniem klasycznych równań Einsteina z członem kosmologicznym.Proces wyłonienia (...) się modelu LCDM z modelu CDM można traktować jako proces emer- gencji epistemologicznej. Wskazujemy na dwa użyteczne pojęcia: bifurkacji i strukturalnej niestabilności, które mogą być użyteczne w konceptualizacji predykatu nowy, w opisie pojęcia emergencji standardowego modelu kosmologicznego. Na marginesie naszych rozważań formułujemy koncepcję bifurkacyjnego rozwoju kosmologii w drodze kolejnej bifurkacji jej parametrów. Wówczas przejście od modelu dynamicznego CDM do modelu LCDM posiada charakter bifurkacji typu widłowego. Ten scenariusz jest zgodny ze scenariuszem nieliniowego rozwoju nauki Michała Hellera. (shrink)

We formulate a cosmogonic indifference principle in cosmology in terms of a dynamical system theory. While the choice between generic and fine tuned initial condition for our Universe has a rather philosophical character, there is a very generic set of initial conditions which give rise to the concordance inflectional ΛCDM model which becomes in good agreement with astronomical observations.

We propose an adynamical, background independent approach to quantum gravity and unification whereby the fundamental elements of Nature are graphical units of space, time and sources. The transition amplitude for these elements of “spacetimesource” is computed using a path integral with discrete Gaussian graphical action. The unit of action for a spacetimesource element is constructed from a difference matrix K and source vector J on the graph, as in lattice gauge theory. K is constructed from graphical relations so that it (...) contains a non-trivial null space, and J is then restricted to the column space of K which ensures it is distributed in a divergence-free fashion over the spacetime defined by the element. This rule for the relational construct of K and J is our proposed fundamental axiom of physics and results in a self-consistency relationship between sources, the spacetime metric, and the stress-energy-momentum content of the element, rather than a dynamical law for time-evolved entities. In its most general form, the set of fundamental elements employed by lattice gauge theory contains scalar fields on nodes and links, and vector fields on nodes. To complete the fundamental set, we propose the addition of scalar fields on plaquettes and vector fields on links. We use this approach via modified Regge calculus to correct proper distance in the Einstein-deSitter cosmology model yielding a fit of the Union2 Compilation supernova data that matches ɅCDM without having to invoke accelerating expansion or dark energy. (shrink)

We present a one per cent measurement of the cosmic distance scale from the detections of the baryon acoustic oscillations in the clustering of galaxies from the Baryon Oscillation Spectroscopic Survey, which is part of the Sloan Digital Sky Survey III. Our results come from the Data Release 11 sample, containing nearly one million galaxies and covering approximately 8500 square degrees and the redshift range 0.2 < z < 0.7. We also compare these results with those from the publicly released (...) DR9 and DR10 samples. Assuming a concordance Λ cold dark matter cosmological model, the DR11 sample covers a volume of 13 Gpc3 and is the largest region of the Universe ever surveyed at this density. We measure the correlation function and power spectrum, including density-field reconstruction of the BAO feature. The acoustic features are detected at a significance of over 7σ in both the correlation function and power spectrum. Fitting for the position of the acoustic features measures the distance relative to the sound horizon at the drag epoch, rd, which has a value of rd,fid = 149.28 Mpc in our fiducial cosmology. We find DV = at z = 0.32 and DV = at z = 0.57. At 1.0 per cent, this latter measure is the most precise distance constraint ever obtained from a galaxy survey. Separating the clustering along and transverse to the line of sight yields measurements at z = 0.57 of DA = and H =. Our measurements of the distance scale are in good agreement with previous BAO measurements and with the predictions from cosmic microwave background data for a spatially flat CDM model with a cosmological constant. © 2014 The Author Published by Oxford University Press on behalf of the Royal Astronomical Society. (shrink)

The Kyoto Protocol and its implementation brought forward issues of climate change and its mitigation strategy by national measures through the creation of market mechanisms in carbon trading. The trading of emission certificates has become an important trade commodity worldwide, and its markets have diversified. While this opportunity has created new markets for entrepreneurs and actors that range from farmers to brokers, unequal involvement in most developing countries is noted. This has been mostly observed in those countries where entrepreneurship is (...) often regarded as the cornerstone of economic growth and social improvement. South Africa has spearheaded other African countries in its implementation of Clean Development Mechanism (CDM) projects leading to carbon trading. Based on our research on South African entrepreneurship and its involvement in the carbon market, we conclude that albeit a number of opportunities, the biggest challenge for entrepreneurial participation in the carbon market remains in the nature and processes of CDM project implementation, the lack of a clear supportive system, limited access to financing and—more importantly—general ignorance of the trading opportunities by entrepreneurs. The complex nature of CDM projects themselves limits participation due to lack of the necessary skills on the national level leading to uneven distribution of CDM projects on provincial levels in South Africa. Recommendations are provided to overcome the obstacles and to promote entrepreneurial activity in the carbon market. (shrink)