Reciprocity of Networks with Degree Correlations and Arbitrary Degree Sequences

Although most of the real networks contain a mixture of directed and bidirectional (reciprocal) connections, the reciprocity $r$ has received little attention as a subject of theoretical understanding. We study the expected reciprocity of networks with an arbitrary degree sequence and a broad class of degree correlations by means of statistical ensemble approach. We demonstrate that degree correlations are crucial to understand the reciprocity in real networks and a hierarchy of correlation contributions to $r$ is revealed. Numerical experiments using novel network randomization methods show very good agreement to our analytical estimations.Comment: 8 pages, 3 figures, added a new table and a new figure, accepted for publication in Phys.Rev.

A shallow-water cyrtocrinid crinoid (Articulata) from the upper Albian of the Western Pyrenees, North Spain

The cyrtocrinid crinoid Proholopus holopiformis (Remeš, 1902) is described from the upper Albian succession that may be included in the Albeniz unit to the east of Iruñea-Pamplona (Navarre, Western Pyrenees, Spain). Although based on partially disarticulated material, this taxon preserve calyx, stem, attachment structure, and brachial plates from the arms. Proholopus holopiformis was previously described from the Upper Jurassic-Lower Cretaceous of the Czech Republic and Lower Cretaceous of France and Crimea, thus the occurrence from Spain represents the youngest of the species. This allows a better characterization of the family Proholopodidae that was originally described based on calyx morphology only and expands its distribution to the upper Albian. Proholopus holopiformis inhabited the fore-reef areas of coral-sponge bioconstructions. Based on coral types, crinoids are thought to have dwelled near the euphotic-oligophotic zones transition and, thus, thrive in shallow depths. Most specimens have bite marks compatible with cidaroid predation. This represents one of the youngest occurrences of cyrtocrinids inhabiting shallow marine environments before their migration to the deep sea due to the ongoing Mesozoic Marine Revolution

Comentarios sobre el Orden Público Internacional en sede arbitral internacional, su funcionalidad y su interrelación con el Derecho internacional público = Some reflections regarding International Public policy in international arbitration, its functionality and its interdependence with Public International Law

 Resumen: El derecho del arbitraje internacional no es estrictamente internacional ni doméstico. A decir verdad, aquel cuerpo legal constituye un producto de la voluntad de las partes que han elegido resol­ver sus litigios mediante aquel tipo de mecanismo de solución de controversias. Ahora bien, aunque ello es así, dichas atribuciones presentan ciertos límites. Y es que, los laudos arbitrales internacionales formulados bajo aquellas libertades, son en estricto una forma de justicia privada y, como resultado de ello, los Estados en donde los mismos busquen ser ejecutados podrán rechazar su implementación en ciertas circunstancias. Una de aquellas circunstancias se produce cuando un laudo arbitral infringe el orden público (ordre public) del Estado donde éste busca ser ejecutado. Esta es una regla ampliamente reconocido, sin embargo, genera un problema. Y es que, la noción del orden público es contingente por naturaleza y, dado ello, ha sido nece­sario que su aplicación proceda solo en circunstancias excepcionales. Como resultado de esto, algunos aca­démicos y tribunales estatales han tratado de formular una noción del orden público de tipo internacional con el fin de establecer un contenido más restrictivo a aquella excepción. Sin embargo, esta terminología ha sido construida solo como una forma de identificar una sub-sección del orden público estatal. Esto lleva a ciertas preguntas: ¿Está el arbitraje internacional y, sus instituciones, circunscritas a elementos puramente domésticos? ¿Dónde queda la faceta internacional de los contratos de comercio internacional y de inver­siones si la excepción del orden público fuese a ser analizada desde un enfoque puramente estatal? Estas dudas han sido –tomadas en cuenta de alguna forma, en algunos sistemas legales, en donde el uso del orden público internacional ha sido estructurado en términos verdaderamente internacionales. Sin embargo, esto último también crea interrogantes a plantearse: ¿Qué implica hablar del orden público en el plano interna­cional? ¿Cuál es su contenido y, puede ser utilizado de forma práctica para excluir la ejecución de un laudo arbitral internacional? ¿Cuál es el rol del Derecho Internacional Público en todo esto? ¿Si el verdadero orden público internacional es utilizado, será aquel un punto de contacto entre el Derecho Internacional Público y el Derecho Internacional Privado? Estas y otras interrogantes serán tratadas en este espacio.Palabras clave: arbitraje internacional, orden público, orden público internacional, ejecución de laudos arbitrales, relación entre el derecho internacional público y el derecho internacional privado.Abstract: International arbitration is not domestic nor international in nature. In fact, the law appli­cable to that kind of proceedings can be considered a byproduct of the will of private parties. However, this wide attribution recognized to individuals have some limits. In this regard, it must be born in mind that arbitral awards represent a sort of private justice and, therefore, States requested to execute those kind of decisions can refuse their enforcement within their jurisdictions. One scenario that entails the non-enforcement of and arbitral award happens when the decision collides with the public policy (ordre public) of the State where is supposed to be implemented. This is widely recognized as a fundamental rule in international arbitration, nevertheless, a problem arises. The notion of public policy is contingent in nature and, because of that, it requires to be applied in very specific circumstances. That is why some academics and state tribunals have formulated the notion of international public policy as a term directed to narrow the content of that institution, but using to that end purely domestic legal content. In this sense, the term international public policy emerged as a merely sub-section of domestic public policy divested of any international meaning. In that context: ¿should international arbitration institutions (as the excep­tion of ordre public), be understood by purely domestic elements? ¿Where would be the international aspect of international commercial contract or investment if the exception of public policy is analyzed by purely domestic constructions? Those doubts have pushed in some systems, the formulation of in­ternational public policy in truly international terms. This is somehow welcomed, however, this usage creates additional doubts: ¿What does a public policy of the international realm entail? ¿What is its content and, can that be used in practical ways to exclude the enforcement of and international arbitral award? ¿What is the role of Public International Law in all of this? ¿If truly international public policy is used by domestic tribunals, would that be a point of connection between Public International Law and Private International Law? These and other questions will be entertained in this paper.Keywords: international arbitration, public policy, international public policy, enforcement of ar­bitral awards, public international law – private international law relationship

Optimal map of the modular structure of complex networks

Modular structure is pervasive in many complex networks of interactions observed in natural, social and technological sciences. Its study sheds light on the relation between the structure and function of complex systems. Generally speaking, modules are islands of highly connected nodes separated by a relatively small number of links. Every module can have contributions of links from any node in the network. The challenge is to disentangle these contributions to understand how the modular structure is built. The main problem is that the analysis of a certain partition into modules involves, in principle, as many data as number of modules times number of nodes. To confront this challenge, here we first define the contribution matrix, the mathematical object containing all the information about the partition of interest, and after, we use a Truncated Singular Value Decomposition to extract the best representation of this matrix in a plane. The analysis of this projection allow us to scrutinize the skeleton of the modular structure, revealing the structure of individual modules and their interrelations.Comment: 21 pages, 10 figure

El Unificador Fragmentado. La fenomenología de las normas de ius cogens en un contexto de cambio

La formulación de una teoría coherente sobre la naturaleza de las normas de ius cogens aun hoy constituye un tema irresoluble para la fenomenología del Derecho Internacional. La fascinación que esta categoría legal produce se cimienta en su habilidad para reflejar todo tipo de implicancias teóricas en las demás instituciones del Derecho Internacional. Por ejemplo, existe una interrelación evidente entre las normas de ius cogens y la fragmentación del Derecho Internacional, conexión que se repiten con otras construcciones, con efectos que ponen en cuestión la propia concepción tradicional de nuestra disciplina. En una situación como esta; ¿Podemos seguir entendiendo las fuentes del Derecho Internacional desde una perspectiva tradicional? ¿Especialmente, después de las decisiones emitidas por órganos de adjudicación internacional aceptando su surgimiento de formas única? ¿La concepción tradicional de las fuentes del Derecho Internacional es suficiente? ¿Podemos afirmar que las normas de ius cogens son productos consuetudinarios, como diferentes autores prominentes defienden? ¿O son Principios del Derecho Internacional? ¿Es correcto formular las normas perentorias como categorías borrosas y, al mismo tiempo, esperar que éstas transformen el Derecho Internacional tradicional? Las siguientes líneas tratarán de brindar respuestas a estas preguntas y describen la naturaleza de estas figuras legales.Ius cogens represent –notwithstanding the great attention directed to them– an irresolvable issue in International Law’s phenomenology. The fascination attached to this legal category lies in its ability to reflect all sorts of theoretical implications to every other institution/phenomena of International Law. For example, there is a very evident interplay between Jus Cogens norms and the fragmentation of International Law, and this linkage can be traced as well in other numerous legal constructions, with effects that question the very essence of our discipline. In a context like this, can we still understand the sources of international law in a traditional way, specially, after the practice of adjudicatory bodies accepting the emergence of Jus Cogens in a very unique fashion? Is the traditional conception of the sources of International Law enough to explain this legal category? Can we conclude that Jus Cogens norms represent customary products, as many prominent authors defend? Or are these, Principle of International Law? In the end, it is correct to allow the existence of a blurred category and at the same time hope, somehow, the transformation of International Law? The following lines will be devoted to sketch some answers to these questions and to explain in some extent the nature of these norms

Perplejidades Normativas y Límites de la Actividad Consultiva de la Corte Interamericana de Derechos Humanos. Algunas Lecciones Provenientes de la Adopción de la Opinión Consultiva OC-23/17 sobre «Medio Ambiente y Derechos Humanos»

In November 2017, the Inter-American Court of Human Rights issued an Advisory Opinion on the Environment and Human Rights. The Opinion had an immediate impact on the human rights legal community. It was the first time the Inter-American Court assessed, from a general point of view, the scope of the obligations of the parties to the American Convention in regards to the protection of the environment, in connection with the fulfillment of the human rights enshrined in that instrument. After the issuance of this decision, a majority of scholars saluted the Court’s approach. We think a critical assessment needs to be performed, to the content of this decision. This paper is an opportunity to discuss the possible flows that might have been committed in the adoption of this Advisory Opinion; particularly, regarding the argumentation that the Court followed to expand its jurisdiction and to make justiciable environmental rights that are not expressly included in the American Convention on Human Rights. Particular emphasis, will be given to the fact that the Court did not use to that end, a contentious procedure, but an Advisory Opinion one, resulting in a decision that –according to the Court– has particular legal effects for the parties to the American Convention.En noviembre de 2017, la Corte Interamericana de Derechos Humanos emitió la Opinión Consultiva sobre Medio Ambiente y Derechos Humanos. Su adopción tuvo un impacto inmediato en la comunidad jurídica; particularmente, al ser la primera vez que la Corte analizó –de forma general–, las obligaciones de los Estados parte de la Convención Americana en lo referido a la protección del medio ambiente, en conexión con la protección de los derechos humanos reconocidos en dicho instrumento. Después de la adopción de esta decisión, la mayor parte de académicos, saludarían su contenido. Sin embargo, nosotros creemos que se requiere una aproximación crítica. Este artículo es una oportunidad para considerar las posibles debilidades presentes en la adopción de aquella Opinión; especialmente, en lo que respecta a la argumentación seguida por la Corte para expandir su jurisdicción y hacer posible la judicialización de derechos ambientales, que no se encuentran consagrados en la Convención Americana. Énfasis particular, será dado al hecho de que –en esta oportunidad–, la Corte no utilizó un procedimiento contencioso para realizar aquella expansión legal, sino que –utilizó con ese fin–, una Opinión Consultiva que, según la misma Corte presenta efectos particulares para los Estados parte de la Convención

From modular to centralized organization of synchronization in functional areas of the cat cerebral cortex

Recent studies have pointed out the importance of transient synchronization between widely distributed neural assemblies to understand conscious perception. These neural assemblies form intricate networks of neurons and synapses whose detailed map for mammals is still unknown and far from our experimental capabilities. Only in a few cases, for example the C. elegans, we know the complete mapping of the neuronal tissue or its mesoscopic level of description provided by cortical areas. Here we study the process of transient and global synchronization using a simple model of phase-coupled oscillators assigned to cortical areas in the cerebral cat cortex. Our results highlight the impact of the topological connectivity in the developing of synchronization, revealing a transition in the synchronization organization that goes from a modular decentralized coherence to a centralized synchronized regime controlled by a few cortical areas forming a Rich-Club connectivity pattern.Comment: 24 pages, 8 figures. Final version published in PLoS On

Influencia de los procesos metabólicos rumiales sobre la calidad nutritiva del componente nitrogenado de la dieta

Se ha estudiado la influencia de los procesos metabólicos que tienen lugar en el rumen sobre el valor nutritivo del componente nitrogenado de la dieta, y se han analizado las repercusiones de la sustitución de parte de la proteína por urea sobre dIcha influencia. El coeficiente de digestibilidad verdadero de la proteína de la digesta duodenal de la ov·eja alimentada con alfalfa o con alfalfa más urea es siempre significativamente superior al de la proteína de la alfalfa. Los cambios en el valor biológico son cualitativamente análogos a los de la digestibilidad, pero cuantitativamente mayores. Les procesos metabólicos ruminales inciden favorablemente sobre la calidad nutritiva del componente nitrogenado de la ingesta; la proteína modificada por estos procesos es más fácilmente absorbible y, sobre todo, más eficazment·e utilizable. Esto es cierto incluso cuando parte del nitrógeno proteico es sustituido por nitrógeno ureico.The influence of ruminal metabolic processes on nutritive value of dietary nitrogen was studied. The effect of replacing protein partially by urea was also analyzed. True digestibility coefficient of duodenal contents protein of sheep fed lucerne is always significatively higher than lucerne protein. Biological value shows similar but larger changes. Ruminal metabolic processes act beneficiously on nutritive quality of food nitrogen compounds; protein modified in this way is more easily ab sorbed and better utilized. When a fraction of proteic nitrogen is replaced by ureic nitrogen the same is true