171,704 research outputs found
Preface: 18th Cologne–Twente Workshop on graphs and combinatorial optimization (CTW 2020)
No full textChirurgia in due fasi nelle IV Classi di Misch tramite dispositivo S.I.S.:un caso clinico
No full textLa ratio nella selezione del lembo di accesso in endodonzia chirurgica:revisione della letteratura
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Megalomma pacifici
No full textMegalomma pacifici (Grube, 1859) Figures 19A–K, 20A–J Sabella pacifici Grube, 1859: 9. Pseudopotamilla panamica Chamberlin, 1919: 268–269, Pl. 3, Fig. 8 fide Knight-Jones, 1997: 314. Megalomma pacifici.— Knight-Jones, 1997: 316, Figs 1A–E. Type material examined. [ZMUC] POL–1985, holotype incomplete (lacking posterior abdomen) of Sabella pacifici Grube, 1859, Punta Arenas, Costa Rica. [MCZ] 72, holotype complete (but broken in two parts) of Pseudopotamilla panamica Chamberlin, 1919, Panama, Coll. A. Agassiz with the following note in label: “In 1937 species identified by Hartman as M. vesiculosum (Montagu), reported in the Bull MCZ Vol. LXIII, No 6: 268–69”. Additional material examined. [Harlan Dean, personal collection ] Costa Rica, Bahía Salinas, Coll. Dean, H., on rocky intertidal (1 female). Playa Panamá, Papaguayo, Colls Dean, H. & J. A. Vargas, August 1999, rocky intertidal (1 spec.). [ZMUC] POL–1986, Costa Rica, Punta Arenas, Realejo, September 1845, Legit Orsted (1 female). [USNM] Acc. 292580, Panama, Shore of Perico Island, Sta. 252–1, lower part of sand beach, soft mud, hard sand/shell, January 25, 1978, Coll. Jones, M. L. (1 spec.). [ECOSUR] OH-P0282, Guerrero, Acapulco, Hornos beach, 16° 51’ 6.4’’ N, 99° 54’ 1’’ W, April 20, 2008, Colls SISV & LFCP, in sponge (1 spec). [ECOSUR] OH-P0284, Oaxaca, Pueto Angel, Panteon Beach, 15° 39’ 51.7’’ N 96° 29’ 44.8’’ W, April 16, 2008, Colls SISV & LFCP, in sabellariid reef (1spec). [ECOSUR] OH-P0285, Guerrero, Acapulco, Hornos beach, 16° 51’ 6.4’’ N, 99° 54’ 1’’ W, April 19, 2008, Colls SISV & LFCP, in oyster Spondylus calcifer (1 spec). [ECOSUR] OH-P0287, Oaxaca, Pueto Angel, Panteon Beach, 15° 39’ 51.7’’ N, 96° 29’ 44.8’’ W, April 16, 2008, Colls SISV & LFCP, in sabellariid reef (1 spec.). [ECOSUR] OH-P0289, Guerrero, Acapulco, Hornos beach, 16° 51’ 6.4’’ N, 99° 54’ 1’’ W, April 19, 2008, Colls SISV & LFCP, in oyster Spondylus calcifer (1 spec.). Diagnosis. Eyes in most radioles (spherical); ocular spots in ventralmost radioles; dorsal margins of collar fused to faecal groove; thoracic chaetae Type C; abdominal chaetae broadly hooded. Description. Branchial crown longer than thorax with 24 radiolar pairs (12–20). Branchial crown with orange bands along entire length (brown in old preserved material). Outer surfaces of radioles quadrangular basally, rounded distally. Sub-distal compound eyes present in most radioles. Dorsalmost pair of radioles with large, spherical and short tips (Figs 19D, 20J). Lateral and ventral radioles with spherical eyes decreasing their size towards ventral radioles (Fig. 19E–F). Ventralmost radioles with ocular spots and long tips (Fig. 19G). Dorsal collar margins rounded posteriorly, fused to faecal groove, forming broad gap (Figs 20B, H, 19A–B). Dorsal lappets absent. Dorsal pockets well developed (Figs 19A–B, 20B, H). Ventral lappets triangular, not overlapping (Figs 19C, 20C, F). Anterior peristomial ring exposed dorsally between dorsal pockets. Lateral margins of collar covering basal union of radioles (Figs 19B–C). Dorsal lips erect, triangular about one-quarter length of branchial crown, with midrib and dorsal pinnular appendages. Ventral lips short, broadly rounded. Ventral sacs present. Caruncle and keel absent. Total thorax-abdomen length 34 (19–34) mm, maximum width 5 (2) mm throughout most of thorax. Seven thoracic chaetigers (7). Dorsal thorax dark, except for faecal groove. Lateral margin of ventral thoracic shields brown colored. Ventral shields orange. Thoracic tori longest on chaetigers 2–3. Tori in chaetigers 2–3 occupy the entire distance between notopodia and ventral shield margins (Figs 19C, 20D–E), contacting shields. Inferior thoracic chaetae Type C (Fig. 19H). Thoracic uncini with crest surmounted by 8–10 rows of numerous minute teeth, handles 2x length of main fang (Fig. 19I). Companion chaetae with teardrop-shaped membranes (Fig. 19I). Abdomen with 40 chaetigers (42–65). Abdominal chaetae broadly hooded (Fig. 19K); chaetae in posterior row longer than those in anterior row. Abdominal uncini with main fang surmounted by 8–10 rows of numerous minute teeth (Fig. 19J). Pygidium trilobed with three groups of 4–5 red pygidial eyespots, unequal in size (Fig. 20I). Abdominal posterior of holotype regenerating (Fig. 20G). Tube attached to large basal stone and composed by shell fragments, echinoderm spines and coralline sand (Fig. 20A). Remarks. Megalomma pacifici, M. circumspectum and M. georgiense n. sp., share the presence of ocular spots in ventralmost radioles. In M. georgiense n. sp., the dorsal collar margins are not fused to faecal groove (fused in M. pacifici and M. circumspectum). Megalomma pacifici differs from M. circumspectum by having the anterior peristomial ring exposed between dorsal pockets (not exposed in M. circumspectum) and the thoracic tori longest in chaetigers 2–3 and in contact with ventral shields (same length in all segments and separate from ventral shields in M. circumspectum).Published as part of Tovar-Hernández, María Ana & Carrera-Parra, Luis F., 2011, Megalomma Johansson, 1925 (Polychaeta: Sabellidae) from America and other world-wide localities, and phylogenetic relationships within the genus 2861, pp. 1-71 in Zootaxa 2861 (1) on page 44, DOI: 10.11646/zootaxa.2861.1.1, http://zenodo.org/record/528635
HETEROCROMATINA CONSTITUTIVA Y LOCALIZACIÓN DE REGIONES ORGANIZADORAS DEL NUCLEOLO EN BATRACHOIDES PACIFICI (GÜNTHER 1861) (TELEOSTEI: BATRACHOIDIDAE)
No full textRESUMEN: Batrachoides pacifici posee un cariotipo 2n=46, NF=64 constituido por 3 pares metacéntricos (M), 4 pares submetacéntricos (SM), 2 pares subtelocéntricos (ST) y 14 pares acrocéntricos (A). Las Regiones Organizadoras del Nucleolo (RON) fueron detectadas en el extremo terminal de los brazos cortos de un par acrocéntrico de tamaño mediano. La tinción secuencial permitió identificar a estos elementos como el par 21. El bandeo C reveló bloques de heterocromatina constitutiva en las regiones centroméricas y pericentroméricas de casi todos los cromosomas. En algunos cromosomas también fueron observadas regiones intersticiales banda-C positivas. Los datos presentados y su comparación con los de otras especies de la familia indican que el estudio del cariotipo tiene un potencial citotaxonómico de gran valor que pueden contribuir a dilucidar las relaciones filogenéticas en los Batrachoididae. Palabras Clave: Heterocromatina Constitutiva (Bandas-C), Regiones Organizadoras del Nucleolo (RON) Abstract: Batrachoides pacifici has a karyotype 2n=46, NF=64 comprising 3 metacentric pairs (M), 4 submetacentric pairs (SM), 2 subtelocentric pairs (ST), and 14 acrocentric pairs (A). The Nucleolus Organizer Regions (NOR) were detected at the terminal short arm of a medium-size acrocentric pair. Sequential staining allowed for identification of these elements as pair 21. C-banding revealed clusters of constitutive heterochromatin located on the centromeric and pericentromeric regions of almost all chromosomes. Interstitial C-band positive regions were also observed in some chromosomes. The data presented and their comparison with those of the other species of the family indicate that the study of the karyotype has a valuable cytotaxonomic potential, a proposition which could prove very useful in contributing to elucidate the phylogenetic relationships of Batrachoididae. Key words: Batrachoides pacifici, constitutive heterochromatin (C-bands), Nucleolus Organizer Regions (NOR
Projected perspective reformulations with applications in design problems
No full textThe Perspective Relaxation (PR) is a general approach for constructing tight approximations to Mixed Integer Non Linear Programs (MINLP) with semicontinuous variables. The PR of a MINLP can be formulated either as a Mixed Integer Second Order Cone Program (provided that the original objective function is SOCP-representable), or as a Semi-Infinite MINLP. In this paper, we show that under some further assumptions (rather restrictive, but satisfied in several practical applications), the PR of a Mixed Integer Quadratic Program can also be reformulated as a piecewise quadratic problem, ultimately yielding a QP relaxation of roughly the same size of the standard continuous relaxation. Furthermore, if the original problem has some exploitable structure, then this structure is typically preserved in the reformulation, thus allowing the construction of specialized approaches for solving the PR. We report on implementing these ideas on two MIQPs with appropriate structure: a sensor placement problem and a quadratic-cost (single-commodity) network design problem
Exact Algorithms for a discrete metric labeling problem
No full textAbstractWe are given a edge-weighted undirected graph G=(V,E) and a set of labels/colors C={1,2,…,p}. A non-empty subset Cv⊆C is associated with each vertex v∈V. A coloring of the vertices is feasible if each vertex v is colored with a color of Cv. A coloring uniquely defines a subset E′⊆E of edges having different colored endpoints. The problem of finding a feasible coloring which defines a minimum weight E′ is, in general, NP-hard. In this work we first propose polynomial time algorithms for some special cases, namely when the input graph is a tree, a cactus or with bounded tree-width. Then, an implicit enumeration scheme for finding an optimal coloring in the general case is described and computational results are presented
PLASMA ARRICCHITO DI PIASTRINE (PRP). METODI DI ESTRAZIONE E POTENZIALITA' D'USO. REVISIONE DELLA LETTERATURA
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