Inferring muscle functional roles of the ostrich pelvic limb during walking and running using computer optimization

Owing to their cursorial background, ostriches (Struthio camelus) walk and run with high metabolic economy, can reach very fast running speeds and quickly execute cutting manoeuvres. These capabilities are believed to be a result of their ability to coordinate muscles to take advantage of specialized passive limb structures. This study aimed to infer the functional roles of ostrich pelvic limb muscles during gait. Existing gait data were combined with a newly developed musculoskeletal model to generate simulations of ostrich walking and running that predict muscle excitations, force and mechanical work. Consistent with previous avian electromyography studies, predicted excitation patterns showed that individual muscles tended to be excited primarily during only stance or swing. Work and force estimates show that ostrich gaits are partially hip-driven with the bi-articular hip–knee muscles driving stance mechanics. Conversely, the knee extensors acted as brakes, absorbing energy. The digital extensors generated large amounts of both negative and positive mechanical work, with increased magnitudes during running, providing further evidence that ostriches make extensive use of tendinous elastic energy storage to improve economy. The simulations also highlight the need to carefully consider non-muscular soft tissues that may play a role in ostrich gait

On the Complexity of Establishing Hereditary Graph Properties via Vertex Splitting

Vertex splitting is a graph operation that replaces a vertex v with two nonadjacent new vertices u, w and makes each neighbor of v adjacent with one or both of u or w. Vertex splitting has been used in contexts from circuit design to statistical analysis. In this work, we generalize from specific vertex-splitting problems and systematically explore the computational complexity of achieving a given graph property Π by a limited number of vertex splits, formalized as the problem Π Vertex Splitting (Π-VS). We focus on hereditary graph properties and contribute four groups of results: First, we classify the classical complexity of Π-VS for graph properties characterized by forbidden subgraphs of order at most 3. Second, we provide a framework that allows one to show NP-completeness whenever one can construct a combination of a forbidden subgraph and prescribed vertex splits that satisfy certain conditions. Using this framework we show NP-completeness when Π is characterized by sufficiently well-connected forbidden subgraphs. In particular, we show that F-Free-VS is NP-complete for each biconnected graph F. Third, we study infinite families of forbidden subgraphs, obtaining NP-completeness for Bipartite-VS and Perfect-VS, contrasting the known result that Π-VS is in P if Π is the set of all cycles. Finally, we contribute to the study of the parameterized complexity of Π-VS with respect to the number of allowed splits. We show para-NP-hardness for K₃-Free-VS and derive an XP-algorithm when each vertex is only allowed to be split at most once, showing that the ability to split a vertex more than once is a key driver of the problems' complexity

Información, redes y narrativas de interés chilenoen el Diario de noticias sobresalientes en Limay Noticias de Europa, de 1700 a 1711

Sin resume

An overview of education and religious content teaching within the Slovenian education system

Šolstvo je eden izmed ključnih elementov, na katerem stoji naša družba. V preteklosti se je sistem šolanja oblikoval in urejal postopoma, skladno z razvojem posameznih držav. Poseben pomen je šolstvo pridobilo, ko ga je pod svoje okrilje vzela državna oblast in začela urejati njegovo organizacijo in vsebino. Avtor nam predstavi ključne mejnike, ki so, gledano z vidika zakonodaje, vplivali na razvoj šolstva pri nas. Pod drobnogled vzame verski pouk in opredeljuje, na podlagi katerih zakonov in odlokov sta se v preteklosti njegov pomen in vsebina spreminjala. Prvoten namen verskega pouka je bil v vzgoji državljanov, vendar se je poudarek skozi zgodovino spreminjal. Veliko je bilo odvisno od zahtev zakonodajalca, ki je sčasoma vedno odločneje posegal v ureditev in vsebino celotnega šolstva, tudi na področje verske vzgoje in izobraževanja. Posebnost naših krajev je, da smo bili Slovenci skoraj 50 let pod močnim vplivom komunizma, ki je radikalno umaknil vsakršno versko vzgojo iz šolskega sistema, kar se pozna še danes. Izgradnja pluralne družbe, ki bo enako obravnavala verne in neverne, je izziv, ki si ga moramo postaviti visoko na prioritetno mesto, da nam bo v času migracij in trkov različnih kultur uspelo ohraniti svojo identiteto ter hkrati v polnosti spoštovati druge.Education is one of the key elements on which our society stands. In the past, the school system has been designed and regulated gradually, in line with the development of individual countries. Education gained special significance when the state authorities took it under their wing and began to regulate its organization and content. The author presents the key milestones that, from the point of view of legislation, have influenced the development of education in Slovenia. It takes a closer look at religious studies and identifies which laws and ordinances have changed its meaning and content in the past. The original purpose of religious studies was in upbringing citizens, but the emphasis has changed throughout history. Much depended on the requirements of the legislator, who over time increasingly resolutely intervened in the regulation and content of the entire school system, including the field of religious education. The peculiarity of our places is that we, Slovenes, have been under the strong influence of communism for almost 50 years, which radically removed any religious education from the school system, which is still seen today. Building a plural society that treats believers and non-believers alike is a challenge that we must prioritize in order to maintain our identity during migrations and clashes of different cultures, while fully respecting others

The Vascularization of the Digestive Tract Studied by Scanning Electron Microscopy with Special Emphasis on the Teeth, Esophagus, Stomach, Small and Large Intestine, Pancreas, and Liver

The periodontal vessels in adult rats show a ladder-like pattern; in guinea pigs molars, by contrast, they present a honey-comb pattern. The vascular architecture in human teeth seems to be similar to that of rabbits. In guinea pigs, rats, rabbits and humans esophagus circumferential vessels give off perforating vessels. In human esophagus the number and diameter of the vessels in the submucous venous plexus decrease from proximal to distal. In the stomach the subepithelial capillary network shows a honey-comb pattern reflecting the arrangement of the gastric pits. A local portal system between the gastric glands and the surface mucosal cells for the transport of HCO3- ions has been suggested. In the small intestine of humans and rabbits the existence of a dual blood supply of the villus has meanwhile been established. It consists of pericryptal capillaries for the lower portion of the villus (tuft pattern) and a direct arterial supply up to the villus tip (fountain pattern). The colonic microvasculature closely resembles that of the stomach. In the pancreas the insulo-acinar portal system is physiologically significant in that it connects the venules draining the islets with the acini. Venous sphincters in the vascular system of the exocrine pancreas of the rat are of particular functional importance. The hepatic sinusoids are supplied both by the hepatic artery and the branches of the portal vein. The peribiliary plexus is supplied by the afferent vessels of the hepatic artery, the efferent vessels drain the plexus either into the sinusoids or into the lobular vein

Saberes hemisféricos: Sarmiento de Gamboa y sus textos sobre el estrecho de Magallanes

This article examines Pedro Sarmiento de Gamboa’s texts on the Magellan region, the formation of specific geographic knowledge, his methods of operation and rhetoric, as well as his critical understanding of the process of mundialization and the place of the Spanish language at the end of the sixteenth century. Textual analysis focuses on the Relación of the irst voyage to the Strait of Magellan, written by Sarmiento in 1580, and on a sonnet of the same author, published in Madrid in 1591, by the end of his life. It also analyzes the reception and usage of Sarmiento’s Relación in Bartolomé Leonardo de Argensola’s Historia de las Islas Malucas (1609) and Bernardo Iriarte’s Viaje al Estrecho de Magallanes (1768).Este artículo estudia los textos de Pedro Sarmiento de Gamboa sobre la región magallánica y la formación de un conocimiento geográico especíico, sus métodos de operación y su retórica, así como su entendimiento crítico de la mundialización y del lugar de la lengua castellana a inales del siglo XVI. El análisis textual se concentra en la Relación del primer viaje al Estrecho de Magallanes, escrita por Sarmiento en 1580, y en un soneto del mismo autor publicado al inal de su vida, en Madrid en 1591; así como en la recepción de dicha relación y su uso en los impresos de Bartolomé Leonardo de Argensola (Historia de las Islas Malucas, 1609) y Bernardo Iriarte (Viaje al Estrecho de Magallanes, 1768)

Noticias sobre las "Cartas y relaciones del Estrecho de Magallanes (1580-1590)", según la edición de Joaquín Zulena Carrandi

No presenta resume

The Microvasculature of the Guinea Pig Ureter. A Scanning Electron Microscopic Investigation

In 24 albinotic guinea pigs (Cavia porcellus) the gross vasculature and the microvascular architecture of the ureter were studied by light microscopy of tissue blocks and by scanning electron microscopy of vascular casts. The guinea pig ureter is supplied by the renal artery proximally, by the aorta and the internal iliac artery in its mid-segment, and by the uterine and prostatic as well as by the vesical arteries distally. The main arterial trunks run alongside the ureter before they branch to send perforating arterioles to the muscular coat and the mucosal lining. The draining venules are found on both sides of the ureter and form transverse anastomoses. Communications between the arterioles are also located on both sides, but longitudinally arranged. The capillary network of the mucosal lining shows an undulating pattern with tortuous vessels and lies just below the epithelium. The muscular coat and the adventitia have no prominent capillaries of their own. Large arteries are embedded in the adventitia, large veins in the lamina propria. In analogy to human anatomy the vascular arrangement found suggests that, if the ureters are excised in transplant surgery, a lateral incision should be used for the abdominal portion, while the pelvic portion is best approached by a medial incision

Esophageal Vasculature in the Guinea Pig: A Scanning Electron Microscope Study of Vascular Corrosion Casts

The esophageal vascularization of adult male and female albinotic Guinea pigs (Cavia porcellus) is studied by means of light microscopically evaluated serial sections and by scanning electron microscopy (SEM) of vascular corrosion casts. Bronchoesophageal artery (cervical portion), direct branches of tha aorta, recurrent branches of the intercostal arteries (thoracic portion) as well as of the left gastric artery (abdominal portion) supply the esophagus; internal jugular vein, inferior thyroid vein (cervical portion), azygos vein, intercostal veins (thoracic portion) and portal vein, gastroepiploic vein and cranial pancreatoduodenal vein (abdominal portion) drain it. Longitudinally arranged arterioles, venules and capillaries lying at the level of the lamina propria of the esophageal mucosa around the whole circumference of the organ are the most striking vascular features, whereby the venules are considered as those vessels from which esophageal varices arise under pathological conditions

“EN EL REINO QUE PIÉLAGO ES DE TIERRA”: EL TERREMOTO DE CONCEPCIÓN DE 1730 EN LIMA FUNDADA DE PEDRO DE PERALTA BARNUEVO

This article is divided into two parts: a study of Pedro de Peralta’s verses on the 1730 earthquake of Concepción, included in his epic poem Lima fundada o Conquista del Perú (Lima, 1732); and a critical edition of them (octaves 55-70 of Canto VII). The study analyzes Peralta’s poem and creates a context for the understanding of earthquake narratives in colonial Andes, proposing that they serve to symbolically link distant geographical areas to the center of the Viceroyalty, and to open spaces for Criollo politics and the praise of dignitaries, such as Bishop Escandón; as well to construct an exemplary scene of Catholic charity and piety. The study also analyzes the limits of the epic genre and official discourse in Lima fundadaEl presente artículo está dividido en dos partes: un estudio de los versos de Pedro de Peralta sobre el terremoto de Concepción en 1730, incluidos en su poema Lima fundada o Conquista del Perú (Lima, 1732); y una edición crítica de dichos versos (octavas 55-70 del canto VII). El estudio crea un contexto para comprender las narrativas de terremotos en el mundo colonial andino, y propone que éstas sirven para conectar simbólicamente puntos geográficamente distantes a la capital virreinal; para abrir espacios a la política criolla y los elogios de dignatarios, como el obispo Escandón; y para construir una escena ejemplar de caridad y piedad católicas. Asimismo, el estudio analiza los límites del género épico y el discurso oficial en Lima fundad