4,304 research outputs found
Lute, Vihuela, and Early Guitar
ProducciĂłn CientĂficaLutes, guitars, and vihuelas were the principal plucked instruments in use in Europe until around
1800. Ancient forms of the lute existed in many parts of the ancient world, from Egypt and
Persia through to China. It appears to have become known in Europe, where its earliest
associations were with immigrants such as the legendary Persian lutenist Ziryab (b. c. 790âd.
852), who was established in Moorish Spain by 822. The origins of the various flat-backed
instruments that eventually became guitars are more difficult to trace. The vihuela is one such
instrument that evolved in the mid-15th century and was prolific in Spain and its dominions
throughout the 16th century and beyond. Very few plucked instruments, and only a handful of
fragmentary musical compositions, survive from before 1500. The absence of artifacts and
musical sources prior to 1500 has been a point of demarcation in the study of early plucked
instruments, although current research is seeking to explore the continuity of instrumental
practice across this somewhat artificial divide. In contrast, perhaps as many as thirty thousand
worksâperhaps even moreâfor lute, guitar, and vihuela survive from the period 1500â1800.
The music and musical practices associated with them are not well integrated into general
histories of music. This is due in part to the use of tablature as the principal notation format until
about 1800, and also because writers of general histories of music have for the most part
ignored solo instrumental music in their coverage. (For example, the Oxford Anthology of
Western Music, Vol. 1 (2018), designed to accompany chapters 1â11 of Richard Taruskinâs
Oxford History of Western Music, does not contain a single piece of instrumental music prior to
Frescobaldi [1637]). Contrary to this marginalized image, lutes, vihuelas, and guitars were a
revered part of courtly musical culture until well into the 18th century, and constantly present in
urban contexts. After the development of basso continuo practice after 1600, plucked
instruments also became frequent in Christian church music, although the lute was widely
played by clerics of all levels, particularly during the Renaissance. It was also one of the
principal tools used by composers of liturgical polyphony, in part because tablature was the
most common way of writing music in score. From the beginning of music printing, printed
tablatures played a fundamental role in the urban dissemination of music originally for church
and court, and plucked instruments were used widely by all levels of society for both leisure and
pleasure. After 1800, the lute fell from use, the guitar was transformed into its modern form with
single strings, and tablature ceased to be the preferred notation for plucked instruments.Este trabajo forma parte del proyecto de investigaciĂłn âLa obra musical renacentista: fundamentos, repertorios y prĂĄcticasâ HAR 2015-70181-P (MINECO/FEDER, UE
Developmental Systems Theory as a Process Theory
Griffiths and Russell D. Gray (1994, 1997, 2001) have argued that the fundamental unit of analysis in developmental systems theory should be a process â the life cycle â and not a set of developmental resources and interactions between those resources. The key concepts of developmental systems theory, epigenesis and developmental dynamics, both also suggest a process view of the units of development. This chapter explores in more depth the features of developmental systems theory that favour treating processes as fundamental in biology and examines the continuity between developmental systems theory and ideas about process in the work of several major figures in early 20th century biology, most notable C.H Waddington
Biological Information, Causality and Specificity - an Intimate Relationship
In this chapter we examine the relationship between biological information, the key
biological concept of specificity, and recent philosophical work on causation. We begin
by showing how talk of information in the molecular biosciences grew out of efforts to
understand the sources of biological specificity. We then introduce the idea of âcausal
specificityâ from recent work on causation in philosophy, and our own, information
theoretic measure of causal specificity. Biological specificity, we argue, is simple the
causal specificity of certain biological processes. This, we suggest, means that causal
relationships in biology are âinformationalâ relationships simply when they are highly
specific relationships. Biological information can be identified with the storage,
transmission and exercise of biological specificity. It has been argued that causal
relationships should not be regarded as informational relationship unless they are
âarbitraryâ. We argue that, whilst arbitrariness is an important feature of many causal
relationships in living systems, it should not be used in this way to delimit biological
information. Finally, we argue that biological specificity, and hence biological
information, is not confined to nucleic acids but distributed among a wide range of
entities and processes
A Developmental Systems Account of Human Nature
It is now widely accepted that a scientifically credible conception of human nature must reject the folkbiological idea of a fixed, inner essence that makes us human. We argue here that to understand human nature is to understand the plastic process of human development and the diversity it produces. Drawing on the framework of developmental systems theory and the idea of developmental niche construction we argue that human nature is not embodied in only one input to development, such as the genome, and that it should not be confined to universal or typical human characteristics. Both similarities and certain classes of differences are explained by a human developmental system that reaches well out into the 'environment'. We point to a significant overlap between our account and the âLife History Trait Clusterâ account of Grant Ramsey, and defend the developmental systems account against the accusation that trying to encompass developmental plasticity and human diversity leads to an unmanageably complex account of human nature
Genetic, epigenetic and exogenetic information
We describe an approach to measuring biological information where âinformationâ is
understood in the sense found in Francis Crickâs foundational contributions to
molecular biology. Genes contain information in this sense, but so do epigenetic factors, as many biologists have recognized. The term âepigeneticâ is ambiguous, and we
introduce a distinction between epigenetic and exogenetic inheritance to clarify one
aspect of this ambiguity. These three heredity systems play complementary roles in
supplying information for development.
We then consider the evolutionary significance of the three inheritance systems. Whilst
the genetic inheritance system was the key innovation in the evolution of heredity, in
modern organisms the three systems each play important and complementary roles in
heredity and evolution.
Our focus in the earlier part of the paper is on âproximate biologyâ, where information
is a substantial causal factor that causes organisms to develop and causes offspring to
resemble their parents. But much philosophical work has focused on information in
âultimate biologyâ. Ultimate information is a way of talking about the evolutionary
design of the mechanisms of development and inheritance. We conclude by clarifying
the relationship between the two. Ultimate information is not a causal factor that acts
in development or heredity, but it can help to explain the evolution of proximate
information, which is
Wright-Fisher diffusion bridges
{\bf Abstract} The trajectory of the frequency of an allele which begins at
at time and is known to have frequency at time can be modelled
by the bridge process of the Wright-Fisher diffusion. Bridges when are
particularly interesting because they model the trajectory of the frequency of
an allele which appears at a time, then is lost by random drift or mutation
after a time . The coalescent genealogy back in time of a population in a
neutral Wright-Fisher diffusion process is well understood. In this paper we
obtain a new interpretation of the coalescent genealogy of the population in a
bridge from a time . In a bridge with allele frequencies of 0 at
times 0 and the coalescence structure is that the population coalesces in
two directions from to and to such that there is just one
lineage of the allele under consideration at times and . The genealogy
in Wright-Fisher diffusion bridges with selection is more complex than in the
neutral model, but still with the property of the population branching and
coalescing in two directions from time . The density of the
frequency of an allele at time is expressed in a way that shows coalescence
in the two directions. A new algorithm for exact simulation of a neutral
Wright-Fisher bridge is derived. This follows from knowing the density of the
frequency in a bridge and exact simulation from the Wright-Fisher diffusion.
The genealogy of the neutral Wright-Fisher bridge is also modelled by branching
P\'olya urns, extending a representation in a Wright-Fisher diffusion. This is
a new very interesting representation that relates Wright-Fisher bridges to
classical urn models in a Bayesian setting
Non-Newtonian channel flowâexact solutions
In this short communication, exact solutions are obtained for a range of non-Newtonian flows between stationary parallel plates. The pressure-driven flow of fluids with a variational viscosity that adheres to the Carreau governing relationship are considered. Solutions are obtained for both shear-thinning (viscosity decreasing with increasing shear-rate) and shear-thickening (viscosity increasing with increasing shear-rate) flows. A discussion is presented regarding the requirements for such analytical solutions to exist. The dependence of the flow rate on the channel half width and the governing non-Newtonian parameters is also considered
Nucleation and growth in two dimensions
We consider a dynamical process on a graph , in which vertices are
infected (randomly) at a rate which depends on the number of their neighbours
that are already infected. This model includes bootstrap percolation and
first-passage percolation as its extreme points. We give a precise description
of the evolution of this process on the graph , significantly
sharpening results of Dehghanpour and Schonmann. In particular, we determine
the typical infection time up to a constant factor for almost all natural
values of the parameters, and in a large range we obtain a stronger, sharp
threshold.Comment: 35 pages, Section 6 update
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