bluuebunny/crossref_metadata_2025_split huggingface dataset:
Poincaré sequences, homoclinic bifurcation, and chaos
Authors: Jordan D W , Smith P 
Published: November 2023

Abstract
Important features can be totally obscured in such a diagram, but Poincare maps can be used to detect underlying structure, such as periodic solutions having the forcing or a subharmonic frequency. In this context the investigation of periodic solutions, nearly periodic solutions, and similar phenomena is to a considerable extent an exploratory matter in which computation plays at the present time a very significant part. A search for hidden periodicities, such as subharmonic periods, is best carried out by starting with a period in mind and then looking for solutions with this period. In that case a variant of the Poincare map is usually more profitable-if the solutions sought have period T, then we should plot on the x, y plane (if two dimensions are being considered) a sequence of points calculated at times T, 2T, 3T, ... along the phase paths starting from various states, and sec whether any of these sequences indicate that we are approaching a periodic solution. However, this does not quite fit the definition of a Poincare map, which does not involve any mention of time intervals but picks out intersections of a phase path under investigation with another given curve (the section’). The two procedures can with advantage for the analysis (especially in multidimensional cases) be brought together in a manner suggested by the following example.
Speciation and the island condition
Authors: Whittaker Robert J , Fernández-Palacios José María 
Published: November 2023

Abstract
it is the circumstance, that several of the islands possess their own species of the tortoise, mocking-thrush, finches, and numerous plants, these species having the same general habitats, occupying analogous situations, and obviously filling the same place in the natural economy of this archipelago, that strikes me with wonder. It may be suspected that some of these representative species, at least in the case of the tortoise and some of the birds, may here-after prove to be only well-marked races; but this would be of equally great interest to the philosophical naturalist . . .(Charles Darwin in 1845, writing about the Galápagos archipelago. From Ridley 1994, p. 79) Having covered the more important microevolutionary processes and outcomes in the previous chapter, the aim of this chapter is to provide the basic frameworks by which we understand macroevolutionary patterns of change on islands.
Island theory and conservation
Authors: Whittaker Robert J , Fernández-Palacios José María 
Published: November 2023

Abstract
The classical paradigm in ecology, with its emphasis on the stable state, its suggestion of natural systems as closed and self-regulating, and its resonance with the nonscientific idea of the balance of nature, can no longer serve as an adequate foundation for conservation. (Pickett et al. 1992, p. 84) The fragmented world of biological communities in the future will be so different from that of the past, that we must reformulate preservation strategies to forms that go beyond thinking only of preserving microcosms of the original community types. (Kellman 1996, p. 115) Our species has had a profound influence on the ecology and biodiversity of the planet, altering the composition and functioning of ecosystems across the globe. Our actions in some respects represent merely the latest driver of change, concentrated largely within one interglacial of a period, the Quaternary (the past c.2 Ma), which has seen repeated dramatic fluctuations in climate.
Fountains
Authors: Berthoz Alain 
Published: November 2023

Abstract
The elegant gastronomic soirees of the Taste-Vin confrérie at the renowned Clos de Vougeot vineyard in Burgundy offer a feast of delectable dishes and fine wines. But palate fatigue quickly sets in, and the pleasure runs the risk of diminishing if the palate is not given a break. Tradition demands that the meal be interrupted by a lemon sorbet whose pallor and simple roundness contrast with the thousand subtleties of the dishes that preceded it. Its acidity provides a reference for better appreciating both the foregoing flavours and those to come. Floating in alcohol, the sorbet takes on the milky colour of a light fog suspended in the silver goblet. The combination of simplicity and sharpness renews the desire of the tongue to venture further. This chapter, devoted to fountains, has a similar role.
Vitality in music and dance as basic existential experience: Applications in teaching music
Authors: Fröhlich Charlotte 
Published: November 2023

Abstract
For about 70 years, following the teachings of Carl Orff and Emile Jaques-Dalcroze (Orff and Keetman 1950; Jaques-Dalcroze 1921), music pedagogy has brought music and movement together, and more time has been given to improvisation in both classroom music lessons and instrumental teaching. It is time to ask what experiences have encouraged this trend, and what research findings may validate a style of teaching that cultivates intuitions for body movement. It is also time to consider developing new teaching approaches that might refine the existing methods.
Apolipoprotein E, Amyloid β Peptide, And Alzheimer‘s Disease
Authors: Wahrle Suzanne E , Holtzman David M 
Published: November 2023

Abstract
Alzheimer‘s disease (AD) is the most common cause of dementia. Pathological examination of brains from AD patients reveals two key features: extracellular deposits of amyloid peptide (AP) and intracellular aggregates of hyperphosphorylated tau protein. It is hypothesized that AP aggregation and deposition is a critical early event in AD pathogenesis that initiates a cascade of events including neuronal dysfunction, tau aggregation and hyperphosphorylation, and neuronal death. These downstream events ultimately result in the cognitive impairments characteristic of AD (Hardy and Selkoe 2002).
Ngf Family Of Neurotrophins And Their Receptors: Early Involvement In The Progression Of Alzheimer‘s Disease
Authors: Mufson Elliott J , Counts Scott E , Fahnestock, Margaret , Ginsberg Stephen D 
Published: November 2023

Abstract
Cholinergic basal forebrain (CBF) neurons of the nucleus basalis (NB) provide the major cholinergic innervation to the cortical mantle, are selectively vulnerable in late-stage Alzheimer‘s disease (AD), and require the neurotrophin nerve growth factor (NGF) for survival. The neurobiological events underlying the eventual demise of NB neurons during the progression of AD remain unknown. Our group investigated the molecular events underlying the degeneration of cholinotrophic basal forebrain neurons in tissue harvested from subjects participating in a longitudinal clinical pathological study of ageing and AD.
Clinical Assessment Of Alzheimer‘s Disease
Authors: Bhattacharyya Sarmishtha , Overshott, Ross , Burns Alistair 
Published: November 2023

Abstract
In the past the symptoms of dementia were often dismissed as an inevitable accompaniment of advanced age. With raised public awareness of dementia, and the development of memory clinics, patients and doctors are now less likely to accept cognitive impairment as ‘just old age ‘. Patients and their carers are increasingly requesting assessment in the hope that they can receive a diagnosis and treatment.
Recurrent Viruses and Theories Of Sexऻ
Authors: Hamilton W D 
Published: November 2023

Abstract
The review by Lin Chao1 on sex in RNA viruses presents a balanced view of the merits of what may be called the ‘positive eugenical ’ and ‘negative eugenical ’ theories of sex as applied to these viruses. Judging between these I share his preference for the negative, both on his specific viral arguments and in general. However, his survey steps across an intermediate yet fairly distinct theory which I think has stronger evidence than either extreme.2 In discussing the influenza virus he comes close to, but doesn ’t mention, some good evidence for this theory.
On First Looking Into A British Treasurey
Authors: Hamilton W D 
Published: November 2023

Abstract
When I was a boy, Britain was way ahead of the rest of the world in the publishing of books on natural history—indeed until quite recently colleagues from America, Eastern Europe and Japan would gasp at the wealth of our productions and wish they had something similar: the pages and pages of coloured plates of set butterflies and moths, of beetles, bugs, painted toadstools, and the colour-illustrated ﬂoras that soon covered not only Britain but also Northern Europe.
How to catch the red queen?
Authors: Ebert Dieter 
Published: November 2023

Abstract
In 1980 Bill Hamilton published a paper with the attention-getting title ‘Sex versus non-sex versus parasite ‘, in which he proposed that parasitic diseases are an important factor for the maintenance of sexual reproduction. This hypothesis came to be known as the Red Queen hypothesis because it is based on the idea that hosts and parasites are in a never-ending race, just as the Red Queen in Lewis Carroll ’s fairy tale cannot stop running, or else she would lose her position. Although the Red Queen hypothesis attracted a lot of attention, more than ten years after it was proposed very little empirical work had yet been conducted on it. Surprisingly, the widespread support that the hypothesis had earned by the early 1990s among many evolutionary ecologists was not based on hard data, but on its plausibility and the increasing recognition that parasites are indeed everywhere.
A View From Mars
Authors: Brown Sam P 
Published: November 2023

Abstract
By the time I encountered the name W. D. Hamilton, I had already abandoned the science of biology as being impossibly dull. As an idle second-year philosophy student, I chanced upon a dog-eared copy of Dawkins ‘ The Selfish Gene on a friend ’s bookshelf. This book knocked my socks off. I was filled with wonder at the forces of evolution, and the force of Bill ’s ideas. Bill ’s memes certainly had a dramatic effect on my behaviour. With near missionary zeal I at last experienced a sense of calling beyond the college bar. Within weeks I was even pleading to be re-admitted to the biology programme I had so gleefully escaped only a year before. Bill had been a biology undergraduate in Cambridge 30 years before me, and had not been enamoured with the prevalent disregard for evolutionary analyses.
Shapes and numbers
Authors: Bradley Christopher J 
Published: November 2023

Abstract
The ‘numbers’ in the title of this chapter are actually integers, but the title is determined by the fact that well-known names for what we consider here are such things as triangular numbers, polygonal numbers, and polyhedral numbers. In this chapter we try to provide material that is either new or less well known, rather than provide what tends to be given in books on recreational mathematics. We start by considering the triangular numbers in some detail, highlighting their connection with the squares, and in particular dealing with the representation of positive integers as the sum of triangular numbers. In doing this we draw attention to the connections that exist between theorems on triangular numbers and square numbers. We point out that any primitive Pythagorean triplet also has its analogue amongst the triangular numbers. We then describe other shapes and the numbers associated with them. Next we consider the problem of determining which polygonal numbers are also square numbers or triangular numbers. For some polygonal numbers only a FB01nite number of them are squares, but for others there are an inFB01nite number. The Pell equation once again features in this problem. Finally, we give a brief account of the Catalan numbers.
Touching Circles and spheres
Authors: Bradley Christopher J 
Published: November 2023

Abstract
It has been known for a long time, see Pedoe (1970), that the curvatures of four mutually touching circles are related by a single straightforward equation. The result was FB01rst obtained by Descartes (1901). In this chapter we show that inFB01nite chains of touching circles, all with integer curvatures, can be formed. This means that the circles involved all have rational radii. Furthermore, we show how to obtain all such chains. In the FB01rst section we deal with the singular case when one of the circles degenerates into a line. In the next section we deal with the case of sequences of mutually touching circles in two dimensions. We then go on to show how to generalise to sequences of mutually touching spheres in three dimensions, and FB01nally to mutually touching hyperspheres in four dimensions. InFB01nite chains exist in all of these cases, and recurrence relations are established to show how they are formed.
Strange and chaotic attractors
Authors: Bertuglia Cristoforo Sergio , Vaio Franco 
Published: November 2023

Abstract
In the early 1970s, mathematicians David Ruelle and Floris Takens introduced the concept of the strange attractor to describe the phenomenon of turbulence (Ruelle and Takens, 1971; see also Ruelle, 1991). A strange attractor is a subset of points in the phase space that is fundamentally different to that of the objects belonging to ordinary Euclidean geometry; it is a geometric object characterized by a dimension that is not an integer number. The French mathematician of Polish origin Benoit Mandelbrot, also in the 1970s, coined the expression ‘fractal’ to indicate geometric objects whose dimension is not integer (Mandelbrot, 1975): strange attractors are fractal objects.
Modelling
Authors: Bertuglia Cristoforo Sergio , Vaio Franco 
Published: November 2023

Abstract
During our entire lives we learn to construct mental models of the world that surrounds us. Catching a falling object by anticipating where it is going to fall before it gets there, understanding the thoughts of an interlocutor before he speaks on the basis of a few signs, deciphering the intentions of an opponent before he acts; these are just a few examples of how we read a situation and its various aspects, something that we all do constantly, constructing models based on our store of previous experiences as well as our attempts or mistakes. As we said in Chapter 1, in science, the study of systems that evolve over time, i.e. of systems whose state changes over time, is particularly interesting. The swinging of a pendulum, the radioactive decay of a substance, the movement of the planets in the solar system, the growth of a plant, the trend in the number of individuals of a particular population in a defined territory, the flow of road traffic along a street or that of telephone communications in a channel and the trend of a stock exchange index, are just some examples of what we mean by a system that evolves over time. In each of the above examples, as in many others, we have a set of states at various points in time and we seek a law of motion that reproduces the succession of these states over time. A large part of scientific work, from the very origins of science onwards, has concentrated on establishing the ‘right’ law of motion to describe the evolution of a system over time, based on observations of a limited set of successive states (Casti, 2000). When these activities lead to the formulation of recurrences (laws) in a mathematical language, then we have a mathematical model.
Linearity as a first, often insufficient approximation
Authors: Bertuglia Cristoforo Sergio , Vaio Franco 
Published: November 2023

Abstract
The perception that we have of reality and, in particular, of the dynamic processes that we observe therein, is such that rarely, if at all, do we witness a direct and strict proportionality between ca use and effect (in more specific contexts, other expressions could be used, such as proportionality between input and output, between stimulus and response, between action and reaction, and more besides). In fact, at times actions of relatively small intensities produce consequences that appear to be disproportionately large with respect to the size of the action, or, vice versa, actions that we consider to have a large intensity have unexpectedly little effect with respect to our expectations. Situations of this nature are very frequent and typical to our perception of reality.
Nonlinear models in social processes: the Volterra-Lotka model applied to urban and regional science
Authors: Bertuglia Cristoforo Sergio , Vaio Franco 
Published: November 2023

Abstract
As we mentioned at the beginning of Chapter 12, several variants of the Volterra-Lotka model have been used to model urban and regional systems. The dynamics obtained generally lead back to those obtained with the ecological models iJlustrated in Chapter 12. Nevertheless, it is evident that ecological models can only be applied through homologies, i.e. purely formal equivalences conducted between the biological sphere and that of urban and regional science; meanings relating to other scientific sectors can under no circumstance be strictly attributed to the magnitudes typical of urban and regional science.
Dynamical systems and chaos
Authors: Bertuglia Cristoforo Sergio , Vaio Franco 
Published: November 2023

Abstract
Before proceeding, we would like to remind readers of a concept that was stated in Chapter 8: by dynamical system we simply mean a system of equations that define the evolution of a set of state variables in discrete or continuous time. It is therefore important not to confuse the abstract mathematical concept of dynamical system, with that of system, which for the sake of clarity we will call real, and which instead refers to the empirical observation of phenomena and to the measurement of series of data. The mathematical models we are examining are written in the form of dynamical systems: therefore the properties of the models that we wil1 be discussing should be considered properties of dynamical systems.
Stability in dynamical systems
Authors: Bertuglia Cristoforo Sergio , Vaio Franco 
Published: November 2023

Abstract
As a mathematical model in the form of a dynamical system evolves, it generates a sequence (sets) of numbers that represent states in a phase space, i.e. an orbit; the meaning that is attributed to these (sets of) numbers depends on different factors, as we have discussed on several previous occasions. Of these, we have the problem of sensitivity to (small) changes in the initial conditions, that is to say the study of ‘by how much’ said changes influence (‘propagate’) the numerical values calculated for future states, provoking large or small variations of the same. The stability characteristics of the orbit have to be analysed, which requires, first and foremost, a definition of stability and a method to quantify it. We will be examining this in this section.
A nonlinear discrete model: the logistic map
Authors: Bertuglia Cristoforo Sergio , Vaio Franco 
Published: November 2023

Abstract
In this section we want to continue our discussion of the growth model presented in Chapter 20, the logistic law, illustrating the dynamics of the version in discrete time (20.4). We are particularly interested in showing how a simple nonlinear growth model such as (20.4), that determines the logistic growth of a population, can in some cases generate chaos. In Chapter 22 we will be illustrating various examples produced by means of numerical simulations, as well as some applications of the logistic map in regional sciences. Readers interested in a complete description of the properties of the dynamics of the logistics map can find detailed and in-depth discussions of the mathematical aspects, which in this text are only briefly mentioned, in two fundamental articles. These are works that have reproposed the logistic map to scholars in recent decades, more than a century after Verhulst introduced it: the work of Robert May (1976), the first, in recent years to examine the properties of the map, and that of Mitchell Feigenbaum (1978), whose content is more technical, in which specific aspects are looked at in more depth and generalized.
Some aspects of the classical vision of science
Authors: Bertuglia Cristoforo Sergio , Vaio Franco 
Published: November 2023

Abstract
Before actually going into the merits of complexity, we would like to define a framework, albeit partial, of the scientific thought in the eras, prior to modern times, in which the concept of complexity was developed. Let us return to astronomy. In the long history of attempts that man has made to formulate predictions for the future, a crucial moment, as we know, was Newton’s discovery that the motion of the planets could be described by a particular type of equation, differential equations, that he himself invented, which, therefore, became the main tool, if not the only one, that enabled scientists to look into the future. From astronomy and, in particular, from the successes achieved in celestial mechanics based on Newton’s brilliant intuitions (1687), dassical science, and more specifically mathematical physics that originated from celestial mechanics, started their extraordinary development.
From determinism to complexity: selforganization, a new understanding of system dynamics
Authors: Bertuglia Cristoforo Sergio , Vaio Franco 
Published: November 2023

Abstract
According to Newtonian theory, as we know, space is assumed to be an absolute entity and time a magnitude independent of the former and reversib]e. All of the processes described within the Newtonian framework are reversible. In other words, there is no way of distinguishing between the motion of a body subjected to the action of a force and that of the same body subjected to a force opposite to the previous one, but with time that goes backwards; both appear to be natural. As we know, this schema is completely based on the concept of space provided by Euclidean geometry; it was accepted, used and deve]oped for over a century, after Newton created it, and became one of the distinguishing elements of Kantian philosophy.
What is complexity?
Authors: Bertuglia Cristoforo Sergio , Vaio Franco 
Published: November 2023

Abstract
Over the past 30 years, there has been considerable progress in studies and research in a number of separate areas that are, however, united by the expression ‘complexity science’. Said research work has led to the development of useful techniques and has generated significant and explicative metaphors. However, to date, the work conducted in this field has not been founded on a coherent ‘complexity theory’ even though it is a commonly used expression (even we will be using it in the following sections), nor has it been formalized into a system of axioms and theorems that can be generally applied across the various disciplines. Our further investigation of the subject of complexity will not be based on an abstract view of the latter; we will be looking more at how it manifests itself.
Complexity and evolution
Authors: Bertuglia Cristoforo Sergio , Vaio Franco 
Published: November 2023

Abstract
In this chapter we will be presenting several applications of the ideas proposed by the new approach of complexity to the evolution of systems, focusing particularly on biological systems and on the appearance of life following a spontaneous process of self-organization. Is there is a general tendency for complexity to increase as a system evolves, just like, in a closed system, there is a tendency of the entropy to increase? This question assumes particular importance, for example, in biology, regarding the evolution of living species, but not only this. The evolution of a complex system is spontaneous, whether it is a natural system, like a galaxy, a planetary system, a biological organism, a crystal, a liquid or a real gas in which the interactions between molecules, etc. are not negligible, or whether it is a social system, such as a human population, an economic aggregate or a language (intended in the strict sense, as a complex of phonemes, words, rules of syntax, etc.). Systems are usual1y assumed to evolve over time towards an increase in complexity, but little or nothing is known of the mechanism that could cause the evolution in that direction, rather than towards a simplification or a reduction in complexity.