The crucial phase of speciation is argued to be the evolution of mating cross-incompatibility (prezygotic incompatibility) between the genotypes distinguishing the prospective species populations. Based on this idea, a single-locus model of speciation is presented, which is shown to be biologically plausible and may help to settle the controversy as to the biological significance of single-locus modes of speciation. The model involves three alleles, two of which characterize in homozygous state the prospective species populations and in heterozygous state their hybrids. (...) The third allele represents a mutant which is equivalent to one of the first two alleles with the exception that it inhibits mating with carriers of the third allele. This third allele is fixed in one population and immigrates into a second population which contains the mutant inhibiting matings with members of the former population. Migration in the reverse direction does not occur. Proceeding from a widely applicable concept of fitness and mating preference it is shown that postzygotic incompatibility (hybrid or heterozygote disadvantage) alone suffices to trigger evolutionary replacement of the extant mating relations in the population receiving immigrants by any arbitrary degree of prezygotic incompatibility. This corroborates Wallace's hypothesis and emphasizes the potential biological relevance of speciation by reinforcement (parapatric speciation) at single gene loci. (shrink)

When applied to a family of sets, the term differentiation designates a measure of the totality of those members which appear in only one of the sets. This basic set theoretic concept involves the formation of intersections, unions, and complements of sets. However, populations as special kinds of sets may share types, but they do not share the carriers of these types; intersections of different populations are thus always empty. The resulting conceptual dilemma is resolved by considering the joint representation (...) of members of different populations that have the same type; populations then intersect with respect to joint representation of types. Two forms of representation reflect relative and absolute characteristics of differentiation by accounting for the distributions of types as relative frequencies within populations (as is commonly done) and as absolute frequencies (including effects of population sizes on differentiation), respectively. Corresponding classes of differentiation measures are developed, and existing measures are discussed in relation to these classes. In particular, the affinity of the measurement of distances between populations and the special case of differentiation of two-population families is examined in order to distinguish between the notions of distance and differentiation. (shrink)

A measure of association is introduced that is based on a conceptual rather than a model approach in order to ensure its broad applicability. The basis of the concept involves two variables or traits and of members of a population. The association of the -state with the -state is measured by the degree to which members of given -state share their -state. This formulation yields an index of association, which is applicable to all categories of traits, including discontinuous and continuous (...) traits as well as combinations of these. Complete association of one trait with the other is equivalent to the existence of a functional relationship of the second to the first trait. Therefore, the degree of association can be understood as the closeness of the relations between two variables to a non-specified functional relationship. This feature in connection with the asymmetry of the index attests its suitability for cause-effect analyses. In fact, the conceptual approach to the measurement of association yields a conclusive method of detection and description of functional relationships between variables together with a method for quantification of the strictness of these relationships. The legitimacy of the correlation coefficient and of disequilibrium indices as measures of association is briefly addressed. (shrink)

Because of their elementary significance in almost all fields of science, measures of association between two variables or traits are abundant and multiform. One aspect of association that is of considerable interest, especially in population genetics and ecology, seems to be widely ignored. This aspect concerns association between complex traits that show variable and arbitrarily defined state differences. Among such traits are genetic characters controlled by many and potentially polyploid loci, species characteristics, and environmental variables, all of which may be (...) mutually and asymmetrically associated. A concept of directed association of one trait with another is developed here that relies solely on difference measures between the states of a trait. Associations are considered at three levels: between individual states of two variables, between an individual state of one variable and the totality of the other variable, and between two variables. Relations to known concepts of association are identified. In particular, measures at the latter two levels turn out to be interpretable as measures of differentiation. Examples are given for areas of application (search for functional relationships, distribution of variation over populations, genomic associations, spatiogenetic structure). (shrink)

The isolation principle rests on defining internal and external differentiation for each subset of at least two objects. Subsets with larger external than internal differentiation form isolated groups in the sense that they are internally cohesive and externally isolated. Objects that do not belong to any isolated group are termed solitary. The collection of all isolated groups and solitary objects forms a hierarchical (encaptic) structure. This ubiquitous characteristic of biological organization provides the motivation to identify universally applicable practical methods for (...) the detection of such structure, to distinguish primary types of structure, to quantify their distinctiveness, and to simplify interpretation of structural aspects. A method implementing the isolation principle (by generating all isolated groups and solitary objects) is proven to be specified by single-linkage clustering. Basically, the absence of structure can be stated if no isolated groups exist, the condition for which is provided. Structures that allow for classifications in the sense of complete partitioning into disjoint isolated groups are characterized, and measures of distinctiveness of classification are developed. Among other primary types of structure, chaining (complete nesting) and ties (isolated groups without internal structure) are considered in more detail. Some biological examples for the interpretation of structure resulting from application of the isolation principle are outlined. (shrink)

On philosophical thoughts of Nikolaus Driyarkara, an Indonesian Jesuit educator and philosopher; collection of articles.

While evenness is understood to be maximal if all types (species, genotypes, alleles, etc.) are represented equally (via abundance, biomass, area, etc.), its opposite, maximal unevenness, either remains conceptually in the dark or is conceived as the type distribution that minimizes the applied evenness index. The latter approach, however, frequently leads to conceptual inconsistency due to the fact that the minimizing distribution is not specifiable or is monomorphic. The state of monomorphism, however, is indeterminate in terms of its evenness/unevenness characteristics. (...) Indeed, the semantic indeterminacy also shows up in the observation that monomorphism represents a state of pronounced discontinuity for the established evenness indices. This serious conceptual inconsistency is latent in the widely held idea that evenness is an independent component of diversity. As a consequence, the established evenness indices largely appear as indicators of relative polymorphism rather than as indicators of evenness. In order to arrive at consistent measures of evenness/unevenness, it seems indispensable to determine which states are of maximal unevenness and then to assess the position of a given type distribution between states of maximal evenness and maximal unevenness. Since semantically, unevenness implies inequality among type representations, its maximum is reached if all type representations are equally different. For given number of types, this situation is realized if type representations, when ranked in descending order, show equal differences between adjacent types. We term such distributions “stepladders” as opposed to “plateaus” for uniform distributions. Two approaches to new evenness measures are proposed that reflect different perspectives on the positioning of type distributions between the closest stepladders and the closest plateaus. Their two extremes indicate states of complete evenness and complete unevenness, and the midpoint is postulated to represent the turning point between prevailing evenness and prevailing unevenness. The measures are graphically illustrated by evenness surfaces plotted above frequency simplices for three types, and by transects through evenness surfaces for more types. The approach can be generalized to include variable differences between types (as required in analyses of functional evenness) by simply replacing types with pairs of different types. Pairs, as the new types, can be represented by their abundances, for example, and these can be modified in various ways by the differences between the two types that form the pair. Pair representations thus consist of both the difference between the paired types and their frequency. Omission of pair frequencies leads to conceptual ambiguity. Given this specification of pair representations, their evenness/unevenness can be evaluated using the same indices developed for simple types. Pair evenness then turns out to quantify dispersion evenness. (shrink)

Beside from the Collegio Romano, the Jesuit Province of Upper Germany with its universities at Dillingen and Ingolstadt was a centre of the intellectual dispute about Perera. Especially his pupil Anton Balduin and the theologian Gregorius de Valencia are central to the controversy. Despite the restraint of the Rector Theodoricus Canisius in the disputations of Balduinus about physics there are theses that show the influence of Balduinus: indeterminate dimensions of prime matter, the question of a maximum and minimum in (...) the natural species, the critics of the aristotelian definition of place, the persistence of forms in elementary mixture. Perera’s history of philosophy in book IV of his De communibus is used several times by Jacobus Pontanus in his discourses at Dillingen university and in his Progymnasmata Latinitatis. (shrink)

En este trabajo se estudia la versión del intelecto agente en cuatro pensadores poco conocidos del s. XIV: 1) Guillermo de Alnwick (Guillelmus de Alnwick). 2) Gregorio de Rimini (Gregorius Ariminensis). 3) Tomás de Bailly (Thomas de Bailly). 4) Pedro de Ailly (Petrus de Ailly).

Divine inspiration through the Holy Ghost is topical in the portraits of Gregory the Great: A dove brings him the divine words, which he writes himself or dictates to his deacon Petrus. Thus the charismatic Father of the Church became, like the Evangelists, a divinely inspired medium who transmitted the mandate of spreading the gospel and guaranteed the heavenly origin of the texts that were recited and sung in the liturgy. The preface ‘Gregorius presul’, which is to be found (...) in variant forms introducing antiphonaries and cantatories, states that Gregory, the “powerful teacher” of church chant, composed the songbooks (composuit hunc libellum musicae artis), thereby sanctifying them. Scholars see in this preface a Carolingian strategy of legitimation based on this dynasty’s theocratic concept of power. Gregorian chant, the quintessence of medieval monophonic tradition, has his origins in the Frankish church adopting the “authentic” Roman rite, which was declared canonical liturgy in all churches of the Frankish empire because of Gregory’s authorship. But the consolidation of Gregory’s myth unintentionally legitimated the process of composition, too, because the connection between the concepts of authorship and inspiration justified the composer’s claim to the ministry of spreading the gospel and of attaining the highest knowledge. (shrink)

In this paper I firstly examine the contents of Escur. Φ III 11, which includes a medical section, an anthology of texts both sacred and profane, and the epistolar exchange between Gregorius Acindynus and Eirene Choumnos. Secondly I go through Eirene’s intellectual background and the books transcribed under her patronage. Thirdly I explain the role played by this Escurialensis in Eirene’s library and in the anti-Palamite circles. Fourthly, basing on different kinds of arguments, I attribute the copying of ff. (...) 83r-156v to Matthew Blastares. (shrink)

A critical review of the editio princeps of the Liber Timothei episcopi de Pascha recently published by Pierre Chambert-Protat and Camille Gerzaguet in the coll. Sources chrétiennes. The article questions the editors’ thesis, at length developed in the Introduction, that the text is only the Latin translation, also known by Gregorius of Elvira and St. Augustine, of a Greek treatise apparently due to one Timothy, bishop of Cybistra in Cappadocia during the first half of the IVth century. It tries (...) to show that this thesis, although not implausible, is not however as strong as its promoters imagine, and that several of their arguments are to be rejected or at least to be qualified. This discussion, which forms the main part of the article, is supplemented by two lists of proposed corrections: the first deals with the Latin text and the second, in an appendix, with its French translation. (shrink)

Questo studio investiga quali siano i punti di contatto tra il filosofo tedesco Friedrich Nietzsche e lo scrittore svedese Hjalmar Söderberg nel romanzo di quest’ultimo Doktor Glas. L’articolo prende in esame due testi nietzschiani finora poco messi in relazione con l’opera söderberghiana, Über Wahrheit und Lüge im außermoralischen Sinne e Die fröhliche Wissenschaft, evidenziando gli influssi che il pensiero del filosofo tedesco ha esercitato sulla concezione del Doktor Glas. L’analisi prende le mosse dai concetti di menzogna e conoscenza così come (...) formulati in Über Wahrheit und Lüge im außermoralischen Sinne e dal concetto di “morte di Dio”, identificando in quest’ultimo il crollo della metafisica nel pensiero filosofico europeo a partire dalla rivoluzione copernicana. Il saggio illustra come a questo cambiamento sia sopraggiunto lo svilupparsi di una nuova sensibilità tecnico-scientifica legata alla physis, cambiamento che vede nella figura del medico il suo massimo esponente. L’articolo mette dunque in luce come nel Doktor Glas il passaggio dalla metafisica alla physis venga rappresentato come un momento di crisi esistenziale, non avendo il medico la capacità di superare il trauma della perdita della metafisica. Quest’incapacità è causata dalla conoscenza, la quale se offre la possibilità di scoprire le menzogne usate dalla società, non consente però di trovare lo stimolo per superare la condizione di vuoto causata dalla “morte di Dio”. Söderberg fornisce dunque nel suo romanzo un’interpretazione pessimistica della crisi di Fin de siècle, inquadrando nella paralisi interiore del dottor Tyko Gabriel Glas e l’omicidio inconcludente del pastore Gregorius il fallimento del passaggio dal paradigma metafisico al paradigma della physis e l’impossibilità di superare la crisi tramite una metamorfosi nella condizione di Übermensch. (shrink)

Die Beschäftigung mit der Hand des Theodoros Skutariotes wird durch das Fehlen eines von ihm subskribierten Exemplars erschwert. Über seine Tätigkeit als Patriarchatsbeamter, Metropolit von Kyzikos und Chronist hinaus ist Theodoros der Forschung jedoch als Handschriftensammler und -besitzer bekannt. Ausgangspunkt jeder Untersuchung zu seinem Schriftstil sind deshalb die Marginalien der Kodizes, die sich in seinem Besitz befanden. Durch seinen autographen, monokondylischen Besitzervermerk †σϰουταϱϊώτου λευίτου θεοδώϱου† konnten bisher sechs Kodizes seiner Bibliothek zugeordnet werden: 1. Marcianus gr. 450, 9./10. Jh., Photius, Bibliotheca. (...) 2. Parisinus gr. 1741, 10. Jh., Sammlung rhetorischer Traktate. 3. Oxoniensis Cromwell 19, 11. Jh. 2. H., Ioannes Chrysostomus, Homiliae 1–45 in Matthaeum. 4. Athous, Kutlumusiu 15 , 12. Jh., Gregorius Nazianzenus; Ioannes Chrysostomus. 5. Parisinus gr. 1234, 13. Jh. 2. H., Nicetas Choniates, Panoplia Dogmatica. 6. Vaticanus gr. 636, 13. Jh. 2. H., Euthymius Zigabenus, In s. Pauli epistulas. (shrink)

Christoph Otto von Schönaich hatte im März 1751 sein Epos Hermann, oder das befreyte Deutschland an Gottsched geschickt. Schönaichs Briefe des Bandes 17 dokumentieren Gottscheds intensive Beschäftigung mit dem Werk, das im September 1751 der Öffentlichkeit mit Gottscheds Einleitung als Nationalepos präsentiert wurde. Als Ratgeber oder Publizist unterstützte Gottsched auch weitere literarische Aktivitäten, so verdankt sich die erste deutsche Ausgabe der Satiren Antioch Dmitrijewitsch Kantemirs einer Anregung Gottscheds. Briefe aus Potsdam informieren über Publikationsvorhaben Julien Offray de La Mettries und anderer (...) Personen im Umfeld des preußischen Hofes. Eine Übersetzung der Poetik des Aristoteles hatte Gottsched 1730 mehrfach in Aussicht gestellt. Nach dessen höflicher Anfrage über den Stand der Dinge begrüßte Gottsched die Übersetzung, die Michael Conrad Curtius fertiggestellt hatte, wenn die Veröffentlichung auch erst 1753 gelang. Der Zürich-Leipziger Literaturstreit findet in mehreren Briefen Ausdruck. So ist einem Bericht des Schleusinger Rektors Johann Heinrich Hausmann zu entnehmen, dass kontroverse Debatten über Klopstocks Messias auch auf gymnasialer Ebene ausgetragen werden. Franz Ignaz (Gregorius) Rothfischer ist erstmals mit einem Brief vertreten, den er noch als Benediktiner unterzeichnet, während Briefe anderer Absender schon den spektakulären Konfessionswechsel erahnen lassen, dessen Vollzug in Leipzig im November 1751 die Öffentlichkeit bewegt. (shrink)