Non-monotonic ageing notions are looked upon as an extension of the corresponding monotonic ageing notions in this work. In particular, the New Better than Used in Expectation (NBUE) and the corresponding non-monotonic analogue New Worse then Better than Used in Expectation (NWBUE) classes of life distributions is considered. Some additional results for the NBUE class are obtained. While many properties of the NBUE class carry over in an analogous way to the NWBUE class, it is shown by means of counterexamples that the moment bounds do not. Some corrective results with respect to popular notions of the NWBUE class are also presented.
In this paper, we provide a comprehensive cross-country validation study of compositional mortality modeling and forecasting methods. Thus, we consider two one-to-one transformations: the cumulative distribution function and the centered log-ratio transformation in compositional data analysis. Between the two transformations, the cumulative distribution function provides a scale-free way to visualize the gender gap and cross-country heterogeneity in the probability of dying by sex and country. Drawing on age-specific period life-table death counts from 24 countries in the Human Mortality Database (2025), we assess and compare the point and interval forecast accuracy of the two transformations, using the same forecasting method. Enhancing the forecast accuracy of period life-table death counts is of significant value to demographers, who rely on such forecasts to estimate survival probabilities and life expectancy, and to actuaries, who use them to price annuities across various entry ages and maturities.
Life-science experimental methods generate vast and ever-increasing volumes of data, which provide highly valuable research resources. However, management of these data is nontrivial and applicable software solutions are currently subject to intensive development. The solutions mainly fall into one of the two groups: general data management systems (e.g. Onedata, iRODS, B2SHARE, CERNBox) or very specialised data management solutions (e.g. solutions for biomolecular simulation data, biological imaging data, genomic data). To bridge this gap between them, we provide Onedata4Sci, a prototype data management solution, which is focused on the management of life science data and covers four key steps of the data life cycle, i.e. data acquisition, user access, computational processing and archiving. Onedata4Sci is based on the Onedata data management system. It is written in Python, fully containerised, with the support for processing the stored data in Kubernetes. The applicability of Onedata4Sci is shown in three distinct use cases -- plant imaging data, cellular imaging data, and cryo-electron microscopy data. Despite the use cases covering very different types of data and user patterns, Onedata4Sci demonstrated an ability to successfully handle all these conditions. Complete source codes of Onedata4Sci are available on GitHub (https://github.com/CERIT-SC/onedata4sci), and its documentation and manual for installation are also provided.
We introduce a mathematical framework for statistical exoplanet population and astrobiology studies that may help directing future observational efforts and experiments. The approach is based on a set of differential equations and provides a time-dependent mapping between star formation, metal enrichment, and the occurrence of exoplanets and potentially life-harboring worlds over the chemo-population history of the solar neighborhood. Our results are summarized as follows: 1) the formation of exoplanets in the solar vicinity was episodic, starting with the emergence of the thick disk about 11 Gyr ago; 2) within 100 pc from the Sun, there are as many as 11,000 (eta/0.24) Earth-size planets in the habitable zone ("temperate terrestrial planets" or TTPs) of K-type stars. The solar system is younger than the median TTP, and was created in a star formation surge that peaked 5.5 Gyr ago and was triggered by an external agent; 3) the metallicity modulation of the giant planet occurrence rate results in a later typical formation time, with TTPs outnumbering giant planets at early times; 4) the closest, life-harboring Earth-like planet would be < 20 pc away if microbial life arose as soon as it did on Earth in > 1 % of the TTPs around K stars. If simple life is abundant (fast abiogenesis), it is also old, as it would have emerged more than 8 Gyr ago in about one third of all life-bearing planets today. Older Earth analogs are more likely to have developed sufficiently complex life capable of altering the environment and producing detectable oxygenic biosignatures.
Physical mechanism for the creation of solar spicules is proposed with three stages of their life cycle. It is assumed that at stage-I, the density hump is formed locally in the xy-plane in lower chromosphere in the presence of temperature gradients of electrons and ions along z-axis (the vertical direction). In this region, the density structure of quasi-neutral $(n_i\simeq n_e=n)$ plasma after taking birth is accelerated in the vertical direction due to the thermal force ${\bf F}_{th} \propto \nabla n(x,y,t) \times (\nabla T_e + \nabla T_i)$. The exact time-dependent analytical solution of two fluid plasma equations is presented assuming that density is maximum at the center and decays away from it gradually. The two dimensional (2D) density structure is created as a step function $H(t)$ in time at bottom of the chromosphere and consequently the vertical plasma velocity turns out to be the ramp function of time $R(t)=t H(t)$ whereas the source term $S(x,y,t)$ for the density follows the delta function $δ(t)$ form. The upward acceleration ${\bf a}=a(x,y)\hat{z}$ produced in this density structure is greater than the downward constant solar acceleration $-{\bf g}_\odot$ in the chromosphere. In the transition region (TR), the temperature gradients are steeper; therefore, the upward acceleration increases in magnitude $g_\odot << a$ and the density hump spends lesser time there. This is stage-II of its life cycle. In stage-III, the density structure enters into corona where the gradients of temperatures vanish and the structure decelerates to zero velocity under the action of the solar gravitational force.
In his seminal paper, Phan Minh Dung (1995) proposed abstract argumentation framework, which models argumentation using directed graphs where structureless arguments are the nodes and attacks among the arguments are the edges. In the following years, many extensions of this framework were introduced. These extensions typically add a certain form of structure to the arguments. This thesis showcases two such extensions -- value-based argumentation framework by Trevor Bench-Capon (2002) and semi-abstract argumentation framework by Esther Anna Corsi and Christian Fermüller (2017). The former introduces a mapping function that links individual arguments to a set of ordered values, enabling a distinction between objectively and subjectively acceptable arguments. The latter links claims of individual arguments to propositional formulae and then applies newly-introduced attack principles in order to make implicit attacks explicit and to enable a definition of a consequence relation that relies on neither the truth values nor the interpretations in the usual sense. The contribution of this thesis is two-fold. Firstly, the new semi-abstract value-based argumentation framework is introduced. This framework maps propositional formulae associated with individual arguments to a set of ordered values. Secondly, a complex moral dilemma is formulated using the original and the value-based argumentation frameworks showcasing the expressivity of these formalisms.
AbstractSome people display a general attitude towards God which does not fulfil the criteria of full-blown faith but also does not amount to lack of faith. I argue that in some cases such an attitude, best described as partial faith, is likely to be the all-things-considered best option – even if God exists and the best possible relationship with God is the greatest possible good. This is because, in a universe as religiously ambiguous as ours, some people seem unable to have full-blown faith, and for some others such faith is likely to be possible only at the cost of contradicting some values relevant for the relationship to God. Somehow paradoxically, God-related worries and doubts leading to spiritual struggles and enquiries can improve one's relationship with God, so that, for some people at some times, the advantages of partial faith may override those of full-blown faith. If I am right, it offers some reason to think that partial faith does not deserve the criticism which has traditionally been directed at it. In addition to that, I argue that, independently of the normative assessment, partial faith is a useful descriptive concept, which can throw light on many issues surrounding faith in general and make it easier to describe some themes belonging to continental philosophy of religion in analytic terms.
Exoplanets orbiting in the habitable zone around M-dwarf stars have been prime targets in the search for life due to the long lifetimes of the host star, the prominence of such stars in the galaxy, and the apparent excess of terrestrial planets found around M-dwarfs. However, the heightened stellar activity of M-dwarfs and the often tidally locked planets in these systems have raised questions about the habitability of these planets. In this letter we examine another significant challenge that may exist: these systems seem to lack the architecture necessary to deliver asteroids to the habitable terrestrial planets, and asteroid impacts may play a crucial role in the origin of life. The most widely accepted mechanism for producing a stable asteroid belt and the late stage delivery of asteroids after gas disk dissipation requires a giant planet exterior to the snow line radius. We show that none of the observed systems with planets in the habitable zone of their star also contain a giant planet and therefore are unlikely to have stable asteroid belts. We consider the locations of observed giant planets relative to the snow line radius as a function of stellar mass and find that there is a population of giant planets outside of the snow line radius around M-dwarfs. Therefore, asteroid belt formation around M-dwarfs is generally possible. However, we find that multi-planetary system architectures around M-dwarfs can be quite different from those around more massive stars.
According to models such as panspermia or the Nebula-Relay hypothesis, the ancestors of life on Earth once lived in molecular clouds. Then what are the energy source and bioenergetics for such lifeforms? In this paper, we propose a new bioenergetic mechanism powered by cosmic ray ionization of hydrogen molecules and we argue that it may relate to or be the origin of chemiosmosis. Based on this mechanism, we suggest that the Last Universal Common Ancestor is a type of lifeform that utilize hydrogen molecules as donors of electron transport chains.
Christian Kuehn, Nils Berglund, Christian Bick
et al.
In this paper, we review several results from singularly perturbed differential equations with multiple small parameters. In addition, we develop a general conceptual framework to compare and contrast the different results by proposing a three-step process. First, one specifies the setting and restrictions of the differential equation problem to be studied and identifies the relevant small parameters. Second, one defines a notion of equivalence via a property/observable for partitioning the parameter space into suitable regions near the singular limit. Third, one studies the possible asymptotic singular limit problems as well as perturbation results to complete the diagrammatic subdivision process. We illustrate this approach for two simple problems from algebra and analysis. Then we proceed to the review of several modern double-limit problems including multiple time scales, stochastic dynamics, spatial patterns, and network coupling. For each example, we illustrate the previously mentioned three-step process and show that already double-limit parametric diagrams provide an excellent unifying theme. After this review, we compare and contrast the common features among the different examples. We conclude with a brief outlook, how our methodology can help to systematize the field better, and how it can be transferred to a wide variety of other classes of differential equations.
Jonathan M. Borwein (1951-2016) was a prolific mathematician whose career spanned several countries (UK, Canada, USA, Australia) and whose many interests included analysis, optimisation, number theory, special functions, experimental mathematics, mathematical finance, mathematical education, and visualisation. We describe his life and legacy, and give an annotated bibliography of some of his most significant books and papers.
Multivariate time series (MTS) prediction is ubiquitous in real-world fields, but MTS data often contains missing values. In recent years, there has been an increasing interest in using end-to-end models to handle MTS with missing values. To generate features for prediction, existing methods either merge all input dimensions of MTS or tackle each input dimension independently. However, both approaches are hard to perform well because the former usually produce many unreliable features and the latter lacks correlated information. In this paper, we propose a Learning Individual Features (LIFE) framework, which provides a new paradigm for MTS prediction with missing values. LIFE generates reliable features for prediction by using the correlated dimensions as auxiliary information and suppressing the interference from uncorrelated dimensions with missing values. Experiments on three real-world data sets verify the superiority of LIFE to existing state-of-the-art models.
The managed-metabolism hypothesis suggests that a cooperation barrier must be overcome if self-producing chemical organizations are to transition from non-life to life. This barrier prevents un-managed, self-organizing, autocatalytic networks of molecular species from individuating into complex, cooperative organizations. The barrier arises because molecular species that could otherwise make significant cooperative contributions to the success of an organization will often not be supported within the organization, and because side reactions and other free-riding processes will undermine cooperation. As a result, the barrier seriously limits the possibility space that can be explored by un-managed organizations, impeding individuation, complex functionality and the transition to life. The barrier can be overcome comprehensively by appropriate management which implements a system of evolvable constraints. The constraints support beneficial co-operators and suppress free riders. In this way management can manipulate the chemical processes of an autocatalytic organization, producing novel processes that serve the interests of the organization as a whole and that could not arise and persist spontaneously in an un-managed chemical organization. Management self-organizes because it is able to capture some of the benefits that are produced when its management of an autocatalytic organization promotes beneficial cooperation. Selection therefore favours the emergence of managers that take over and manage chemical organizations so as to overcome the cooperation barrier. The managed-metabolism hypothesis shows that if management is to overcome the cooperation barrier comprehensively, its interventions must be digitally coded. In this way, the hypothesis accounts for the two-tiered structure of all living cells in which a digitally-coded genetic apparatus manages an analogically-informed metabolism.
This paper starts with a biographical sketch of the life of Josef Meixner. Then his motivations to work on orthogonal polynomials and special functions are reviewed. Meixner's 1934 paper introducing the Meixner and Meixner-Pollaczek polynomials is discussed in detail. Truksa's forgotten 1931 paper, which already contains the Meixner polynomials, is mentioned. The paper ends with a survey of the reception of Meixner's 1934 paper.
It is a measure of the importance and profundity of Marvin Kenneth Simon's contributions to communication theory that this tribute article and tutorial about his life and work is of current research relevance in spite of the continually accelerating rate of evolution in this area. Marv, as the entire community affectionately knew him, was one of the most prolific and influential communications researchers of his generation. Moreover, he laid the foundation for many of the techniques used in communication systems today. Marv's tragic death on September 23, 2007 continues to engender pangs not only of sadness at the passing of a great friend to many in our community, but also of regret that he is no longer with us to help in resolving the many challenges facing communication systems today.
S. Blair Hedges, Julie Marin, Michael Suleski
et al.
Genomic data are rapidly resolving the tree of living species calibrated to time, the timetree of life, which will provide a framework for research in diverse fields of science. Previous analyses of taxonomically restricted timetrees have found a decline in the rate of diversification in many groups of organisms, often attributed to ecological interactions among species. Here we have synthesized a global timetree of life from 2,274 studies representing 50,632 species and examined the pattern and rate of diversification as well as the timing of speciation. We found that species diversity has been mostly expanding overall and in many smaller groups of species, and that the rate of diversification in eukaryotes has been mostly constant. We also identified, and avoided, potential biases that may have influenced previous analyses of diversification including low levels of taxon sampling, small clade size, and the inclusion of stem branches in clade analyses. We found consistency in time-to-speciation among plants and animals, approximately two million years, as measured by intervals of crown and stem species times. Together, this clock-like change at different levels suggests that speciation and diversification are processes dominated by random events and that adaptive change is largely a separate process.
Through the use of a system-building approach, an approach that includes finding common ground for the various philosophical paradigms within statistics, Erich L. Lehmann is responsible for much of the synthesis of classical statistical knowledge that developed from the Neyman--Pearson--Wald school. A biographical sketch and a brief summary of some of his many contributions are presented here. His complete bibliography is also included and the references present many other sources of information on his life and his work.
We report the discovery of a planet with a high planet-to-star mass ratio in the microlensing event MOA-2009-BLG-387, which exhibited pronounced deviations over a 12-day interval, one of the longest for any planetary event. The host is an M dwarf, with a mass in the range 0.07 M_sun < M_host < 0.49M_sun at 90% confidence. The planet-star mass ratio q = 0.0132 +- 0.003 has been measured extremely well, so at the best-estimated host mass, the planet mass is m_p = 2.6 Jupiter masses for the median host mass, M = 0.19 M_sun. The host mass is determined from two "higher order" microlensing parameters. One of these, the angular Einstein radius θ_E = 0.31 +- 0.03 mas, is very well measured, but the other (the microlens parallax π_E, which is due to the Earth's orbital motion) is highly degenate with the orbital motion of the planet. We statistically resolve the degeneracy between Earth and planet orbital effects by imposing priors from a Galactic model that specifies the positions and velocities of lenses and sources and a Kepler model of orbits. The 90% confidence intervals for the distance, semi-major axis, and period of the planet are 3.5 kpc < D_L < 7.9 kpc, 1.1 AU < a < 2.7AU, and 3.8 yr < P < 7.6 yr, respectively.