3,605 research outputs found
Saddle towers and minimal <i>k</i>-noids in ℍ<sup>2</sup> × ℝ
No full textAbstractGiven k ≥ 2, we construct a (2k − 2)-parameter family of properly embedded minimal surfaces in ℍ2 × ℝ invariant by a vertical translation T, called saddle towers, which have total intrinsic curvature 4π(1 − k), genus zero and 2k vertical Scherk-type ends in the quotient by T. Each of those examples is obtained from the conjugate graph of a Jenkins–Serrin graph over a convex polygonal domain with 2k edges of the same (finite) length. As limits of saddle towers, we obtain properly embedded minimal surfaces, called minimal k-noids, which are symmetric with respect to a horizontal slice (in fact they are vertical bi-graphs) and have total intrinsic curvature 4π(1 − k), genus zero and k vertical planar ends.</jats:p
Cryptodacus bernardoi Rodriguez & Rodriguez, new species
No full textCryptodacus bernardoi Rodriguez & Rodriguez, new species Figs. 1, 2, 5 –8, 14, 15, 19, 22, 23, 28 –31, 38– 42 Diagnosis. Modified couplets to the latter are provided to include C. bernardoi. It differs from all other species of Cryptodacus in the strongly sinuous shapes of the apical section of vein R 4 + 5 and crossvein dm-m. It differs from all other species except C. obliquus Hendel in lacking brown markings on the face; from all other species except C. trinotatus by the form of the sublateral postsutural vitta on the scutum, which is almost complete, but interrupted anterior to the intra-alar seta; and from other species except C. tau (Foote) by the entirely yellow abdominal syntergite 1 + 2 (Figs. 22, 23). Other useful diagnostic characters include: gena (Figs. 5, 6,) entirely yellow; posterior side of head yellow except lateral occipital sclerite with elongate brown spot; scutellum with base brown, brown area extended to basal scutellar seta; wing (Fig. 19) cell dm with basal and apical hyaline areas, discal band covering posterior part of crossvein dm-m, middle of dm-m without brown border; abdominal tergites 3–4 with broad brown bands, that on tergite 5 sometimes narrowly divided into 3 parts; oviscape yellow (Figs. 1, 20); aculeus tip with large serrations (Figs. 28–30). Description. Length 4.8 –5.0 mm. Mesonotum length 1.5–1.7 mm. Wing length 3.2–3.5 mm, width 1.3–1.5 mm, length/width ratio: 2.3. Measurements made on holotype female and one paratype male. Head (Figs. 5–8): Mostly pale yellow. Ocellar tubercle brown. Orbital plate with irregular brown stripe. Frons with pair of large dark brown spots aligned with and including base of middle frontal seta. 3 frontal setae; 2 orbital setae, well separated, distance between them 2.3–2.6 times distance from anterior seta to eye margin. Ocellar setae weak, 1.5 –2.0 times length of ocellar tubercle. Lunule entirely dark brown. Face entirely pale yellow, without brown spots; ventral margin strongly arched; gena and postgena entirely pale yellow. Posterior side of head entirely pale yellow except lateral occipital sclerite with elongate brown spot. Clypeus, prementum and palpus entirely yellow. Antenna with scape and pedicel yellow, first flagellomere dark yellow except moderate brown on apex, elongate, 4.5 –5.0 times as long as wide, apex flattened, in lateral view rounded. Arista short pubescent on distal half. Thorax (Figs. 14, 15): Mostly dark brown to black, with following whitish markings: postpronotal lobe and presutural lateral margin of scutum, connected to band on transverse suture; band on transverse suture (interrupted medially), extended across posterior part of notopleuron and posterior margin of anepisternum, almost reaching katepisternum; elongate spot on dorsal margin of katepisternum, not extending to katepisternal seta; single medial and paired sublateral postsutural vittae on scutum, medial vitta short, extended anteriorly almost to level of transverse suture, and posteriorly to midway between levels of acrostichal and dorsocentral setae, lateral vitta connected to band on transverse suture, extending almost to level of postalar seta but not reaching intra-alar seta; rectangular area posterior and lateral to intra-alar seta; and scutellum except base, brown part extending to and including base of basal scutellar seta. Scutum entirely microtrichose. Chaetotaxy normal for genus, postpronotal, 2 notopleural, 1 anepisternal, anepimeral, katepisternal, postsutural supra-alar, intra-alar, postalar, dorsocentral, acrostichal, and 2 scutellar setae well developed. Presutural supra-alar seta relatively small, half to two-thirds size of postsutural supra-alar seta. Dorsocentral seta aligned one-half to two-thirds distance from postsutural supra-alar seta to postalar seta. Legs mostly pale yellow, mid and hind coxae with small lateral brown areas, fore and mid tibiae pale brown, hind tibia dark brown, all tarsi pale brown. Wing (Fig. 19): With 4 bands: subbasal band, entirely brown, extended from cells bc and c to midlength of vein CuA+CuP, covering base of cell br, all of cells bm and bcu, and base of cell m 4 (except bordering fold); discal band, connected to subbasal band in cell c, curved posteriorly and extended to posterior wing margin distally in cell m 4, covering cell r 1 posterior to pterostigma, base of cell r 2 + 3, apex of cell br, crossvein r-m and posterior half of crossvein dm-m, dark brown anteriorly, from cell r 1 to middle of cell dm orange medially with broad, dark brown margins, posterior quarter paler brown; narrow, brown subapical band from distal part of cell r 1 to anterior end of crossvein dm-m, faint in cells r 1 and r 2 + 3; and narrow faint brown anterior apical band from distal part of cell r 2 + 3 to apex of vein M 1. Vein M 4 very narrowly bordered by brown between subbasal and discal bands. Cell dm with anterior apical corner hyaline. Crossvein r-m at 0.71 distance from bm-m to dm-m, entirely covered by dark brown distal margin of discal band. Crossvein dm-m and apical section of vein R 4 + 5 sinuous. Abdomen (female, Figs. 1, 22, male, Figs. 2, 23): Predominantly yellow, including all of syntergite 1 + 2. Tergite 3 with broad dark brown band. Tergite 4 and female tergite 5 with broad dark brown band or series of narrowly separated rectangular marks. Male tergite 5 laterally with paired ovoid brown marks, longer than wide, and medially with much smaller, inverted U-shaped brown mark or pair of brown spots. Female tergite 6 laterally with paired rectangular brown mark, medially usually with two small brown spots. Tergites with sparse black setulae. Female terminalia (Figs. 22, 28– 31): oviscape pale yellow, 0.89–0.92 mm long (n= 2). Aculeus (Fig. 28) 0.60 mm long, tip (Figs. 29, 30) 0.10 mm long, with apical 0.04 mm triangular and serrate, 0.05 mm wide, with 6–9 teeth on each side. Two spermathecae (Fig. 31) subcylindrical, with helical surface texture and elongate base. Male terminalia (Figs. 38–42): epandrium in lateral view wider than long, dorsally dark brown with black setulae, ventrally pale brown. Lateral surstylus in lateral view 3.5 times longer than wide, with glabrous, slightly curved elongated acute apex and distinct anteromedial lobe. Medial surstylus elongate two-thirds as long as lateral surstylus. Proctiger ovoid, entirely membranous, with sparse minute brown setulae. Distiphallus (Figs. 39, 41) moderately long and slender in ventral and lateral views, apex of internal tube bilobed. Type data. Holotype ♀ (IAvH), COLOMBIA: Cundinamarca: Anolaima, Vereda Santo Domingo, finca Villa Mariana [4.80171 °N 74.47542 °W], 1532 m, multilure trap, 3 Sep 2015, P. A. Rodriguez, A. L. Norrbom. Paratypes: COLOMBIA: Cundinamarca: Anolaima, Vereda Santo Domingo, finca Villa Mariana, 1532 m, multilure trap, 3 Sep 2015, P. A. Rodriguez, A. L. Norrbom, 1 ♂ (USNM); same locality, multilure trap, 21 Sep 2015, P. A. Rodriguez, 2 ♀ (ICAMF 00000044); same, multilure trap, 28 Sep 2015, P. A. Rodriguez, 2 ♀ (FSCA); same locality, reared from fruits of Phoradendron sp. near piperoides (Kunth) Trel., collected 13 Sep 2015, emerged 1 Oct 2015, P. A. Rodriguez, 1 ♂ 2 ♀ (USNM). Guaduas, Vereda el Raisal, predio el Cajón km 39 vía Bogotá-Guaduas [5 º07’09”N 74 º 57 ’02”W], 1421 m, McPhail trap 18, 22 Aug 2014, E. Quiroga, 1 ♂ 1 ♀ (ICAMF 00000045). Distribution. Cryptodacus bernardoi is known only from Colombia in Cundinamarca department in the municipios of Anolaima and Guaduas at middle altitudes on the west side of the eastern cordillera. Host plant. Three of the paratypes were reared from tiny fruits of Phoradendron sp. near piperoides (Kunth) Trel. (Figs. 43, 44), which was found parasitizing the upper part of a Psidium guajava L. shrub. This host plant is locally known by the common names “muérdago”, “matapalo”, “injerto” and “pajarito”. Phoradendron is variously classified in the Santalaceae or Viscaceae. The only previous host data for Cryptodacus was the single record of C. silvai Lima from fruit of “herva de passarinho” (Loranthus sp.) from southern Brazil (Lima 1947). The Loranthaceae, Santalaceae (and Viscaceae, when recognized as distinct from Santalaceae) belong to the order Santalales, many of which are parasitic plants. Etymology. This species is named for José Bernardo Rodríguez, father of the senior author. Comments. This species runs with difficulty in the keys of Norrbom (1994) and Norrbom & Korytkowski (2008). C. bernardoi may be most closely related to C. lopezi Norrbom, which has a similar aculeus, or it may belong to a clade along with that species and C. tau and trinotatus. The abdominal pattern is intermediate between those species, which have a distinct medial brown vitta or pair of vittae bordered by white or yellow sublateral areas on at least tergite 5 and female tergite 6, and the predominantly brown pattern in other species. In C. bernardoi the bands on tergites 4–5 in the male and 5–6 in the female may be interrupted. These four species also have the head mostly or entirely yellow posteriorly. The males were described only for C. bernardoi, C. obliquus, C. parkeri and C. tau.Published as part of Rodriguez, Pedro Alexander, Rodriguez, Erick J., Norrbom, Allen L. & Arévalo, Emilio, 2016, A new species and new records of Cryptodacus (Diptera: Tephritidae) from Colombia, Bolivia and Peru, pp. 276-290 in Zootaxa 4111 (3) on pages 277-279, DOI: 10.11646/zootaxa.4111.3.5, http://zenodo.org/record/26487
Identificación de malezas en fincas cultivadas con banano en la zona bananera del Magdalena (región norte de Orihueca).
No full textEl presente estudio se realizó en treinta (30) fincas del corregimiento de Orihueca (Zona Bananera del Magdalena), en el segundo semestre del año 1982 (agosto - septiembre). La Zona Bananera del Magdalena, está ubicada en la parte Noroccidental del Departamento del Magdalena, entre el Litoral Atlántico y el Rio Fundación y se encuentra enmarcada en las siguientes coordenadas geográficas longitud oeste: 740 07' - 740 24' Latitud Norte : 110 01' - 10° 22' La altura sobre el nivel del mar de la zona estudiada varía entre 2 y 80 m una precipitación promedio anual de 1500 mm, una temperatura promedio de 30.5° y una humedad relativa de 80.5%. Para realizar la colección de las malezas se dividió imaginariamente cada finca en 6 estratos de diferentes áreas, tomando en cada estrato 3 muestreos, al azar de 1 M2 y en cada uno de ellos se determinó el total de las plantas en el metro cuadra do, el número de cada uno de los especímenes presentes; por cada espécimen se tomaron 3 ejemplares, los cuales se formalizaron para luego someterlos al proceso de conservación en el herbario de la Universidad Tecnológica del Magdalena. Los ejemplares fueron identificados con la ayuda del Doctor Henry Sogamoso y la señora Neovis de López, utilizando para e lb o el material con que cuenta el herbario de la Universidad, además de claves y textos básicos para este tipo de trabajos El porcentaje de malezas de hoja ancha y hoja angosta se de - terminó sumando las malezas que se encontraron en los 180 muestreos de éstas se sacaron el total de malezas de hoja ancha y hoja angosta y mediante una relación se determinó el porcentaje. De igual manera se procedió para la obtención del porcentaje individual de cada maleza En los 180 muestreos realizados en las fincas encuestadas se contabilizaron un total de 2.603 malezas en ellas se encontraron 22 familias, 35 géneros y 40 especies. Del total de las malezas contabilizadas se encontró que el 62.97% pertenecen al tipo de malezas de hoja angosta y el 37.03% a malezas de hoja ancha La familia que se presentó con mayor incidencia fue la Cypera ceae y la familia Boraginaceae presentó menor porcentaje de in cidencia. La especie que se present6 con mayor frecuencia fue Cyperus rotundus L. en tanto que Amaranthus spinosua L. fue la de menor incidencia En la zona estudiada la maleza de hoja angosta que se presentó con mayor frecuencia fue Cyperus rotundus L. y la maleza de ho ja ancha que se presentó con mayor incidencia fue Doxantha ung1112-cati L. la maleza Cyperus globulosus Aubl y Eleusine indi ca (I) Garent se presentaron con menor incidencia, en tanto que Amaranthus spinosus L. fue la maleza de hoja ancha que pre sentó menor porcentaje de incidencia La finca que presentó mayor población de malezas fue San Jacin to II, siendo la finca liaría Luisa la de menor población La finca que mostró un mejor programa de control de malezas fue la finca María Luisa y la finca San Jacinto I fue la que mayor población de malezas presentó
Evaluación de efectos generados por cambio de políticas institucionales en el rendimiento académico de estudiantes de ingeniería industrial de la Universidad del Magdalena a través de cadenas de Markov
No full textA través de este proyecto de investigación, se busca evaluar el impacto de las nuevas modalidades de grado en el programa de Ingeniería Industrial por medio de una matriz markoviana en la cual se evaluaran no solo el tiempo promedio que tarda un estudiante de ingeniería industrial de la universidad del Magdalena, desde el momento que inicia su carrera, hasta cursar sus créditos académicos y de este punto hasta que se titula, el tiempo que permanece cesante el estudiante desde que termina sus créditos hasta que toma el grado, basándose en factores como la cantidad de créditos cursados, cancelación de semestres, cantidad de créditos perdidos, entre otros; sino también, la determinación de cuál de las diferentes modalidades es más demandada por los estudiantes, la probabilidad de deserción académica en el avance por semestres, entre muchos más aspectos que se deben tener en cuenta para mejorar falencias que afectan al programa de Ingeniería Industrial de esta casa de estudio
La oralidad fingida en La profezia dell'armadillo de Zerocalcare: reflexiones en torno a la traducción de la variación lingüística
No full textThis study examines the graphic novel La profezia dell’armadillo (The Armadillo Prophecy, 2011) by Zerocalcare, an autobiographical comic -the author describes a personal journey from his early childhood years to the present day– which occupies a central position in his narrative career. This novel, moreover, provides an exceptional gateway into Zerocalcare’s storytelling and his media or transmedia ecosystem. The article is organized by first reviewing the concept of feigned orality. Thereafter, the notion of transmedia storytelling is presented and illustrates the author's biographical and creative trajectory. Based on the words of the author himself –“scrivo come parlo” (I write how I speak, 2015)– we identify the idiolect of the main characters, a mixture of standard Italian and expressions in Romanesco dialect, and analyse the Spanish translation. Finally, we draw some conclusions on the translation method used to render the Romanesco dialect, based on a comparison of some original and translated segments from the novel
Influencia de corredores biológicos sobre murciélagos en un paisaje fragmentado del Magdalena Medio, Colombia
No full textLa fragmentación del hábitat es una de las principales amenazas para la biodiversidad a nivel mundial. En Colombia, el Magdalena Medio, una región altamente intervenida debido a la agricultura y ganadería extensiva, enfrenta graves desafíos en la conservación de su biodiversidad. Para mitigar estos efectos, se han implementado proyectos de restauración para recuperar la conectividad de las especies, incluyendo la creación de corredores biológicos para el paso de fauna entre parches de bosque. En este estudio se evaluó el efecto de los corredores biológicos, como estrategia de restauración, sobre la composición y diversidad de murciélagos en un bosque fragmentado del Magdalena Medio (Cimitarra, Santander). Para ello, se emplearon 57 redes de niebla para capturar murciélagos en cuatro tipos de coberturas: potreros, corredores sembrados, corredores naturales y fragmentos de bosque, y se analizó y comparó la composición y diversidad taxonómica y funcional de especies en cada una de estas. Los resultados mostraron que los corredores biológicos actúan como hábitats intermedios, favoreciendo la conectividad y sosteniendo una mayor diversidad de murciélagos en comparación con los potreros. Además, los corredores preservan funciones ecosistémicas clave para los murciélagos, destacando su papel fundamental en la restauración ecológica de paisajes fragmentados. Este estudio contribuye al entendimiento de estrategias de restauración en la conservación de murciélagos en el Magdalena Medio.Fundación Proyecto PrimatesPregradoEcología y conservació
A preliminary evaluation of shallow-water rhodolith beds in Bahia Magdalena, Mexico
No full textThe aim of the present study was to describe the structure of shallow-water rhodolith beds from Bahia Magdalena, one of the most productive estuarine systems of the Mexican Pacific coasts. From September 2008 to May 2009 four rhodolith beds were found (between 1 and 3 m depth) and population descriptors such as rhodolith density, size classes, branch density, volume and weight were determined. The dominant rhodolith forming species was Lithophyllum margaritae. The size of beds ranged from 7,600 to 17,800 m2 approximately with densities from 42.2 to 215.9 ind.m-2. In these beds, L. margaritae shows fruticose and foliose growth forms, from which spherical forms were predominant (81-99%). Branch density (from 3.0 to 13.3 branches.cm-2) varied significantly (p O objetivo do presente estudo foi descrever a estrutura de bancos de rodolitos de áreas rasas da Bahia Magdalena, um dos sistemas estuarinos mais produtivos da costa pacífica mexicana. Quatro bancos de rodolitos situados entre 1 e 3m de profundidade foram avaliados em relação a densidade, classes de tamanho, densidade dos ramos, volume e peso no período de setembro de 2008 a maio de 2009. A espécie dominante no local foi Lithophyllum margaritae. O tamanho dos bancos variou de 7,600 a 17,800 m² aproximadamente, com densidades de 42.2-215.9 ind.m-2 . Foram observadas formas de crescimento fruticosa e folhosa em L. margaritae, sendo a forma esférica predominante (81-99%). A densidade dos ramos (3.0-13.3 ramos.cm-2) variou significativamente (p < 0.05) entre os bancos. O volume médio (2.0-400 ml) e o peso úmido (32.4-84.8 g) não tiveram diferenças significativas entre os locais, mas uma correlação positiva significativa (r = 0.95, p < 0.05) foi encontrada entre os parâmetros. O tamanho das plantas variou de 2.0 a 11.5 centímetros predominando o padrão entre 40.1-60 mm. As diferenças na densidade de rodolitos, densidade dos ramos e a esfericidade foram atribuídas às condições hidrodinâmicas diferenciadas nos locais. Estes bancos também foram um importante habitat para uma grande diversidade de esponjas associadas. A ordenação das amostras com o escalonamento multidimensional não-métrico (MDS) indicou grande variabilidade na distribuição das assembléias de esponjas entre os bancos, estas diferen��as provavelmente são resultado de diferenças nas condições ambientais. Embora estes bancos de rodolitos não sejam tão extensos quanto os de outras regiões, nossas pesquisas preliminares revelaram que estes bancos são um habitat comum na Bahia Magdalena e provavelmente têm um papel importante na produtividade do sistema estuarino da região
El ser racializado: el concepto de raza en las experiencias autobiográficas de Richard Rodriguez y Kevin R. Johnson
No full textabstract: Race is a complex system founded on social ideologies that categorize and evaluate human beings into different groups based on their visible characteristics (e.g., skin color) that, according to this notion of race, indicate a person's personal traits (e.g., intelligence). The concept of race has been an integral part of American society since the ratification of the United States Constitution in the late 18th century. Early on, the practice of race within American society established one particular group as the norm: the White Anglo-Saxon Protestant. By the late 19th and early 20th centuries, the distinctions among racial groups essentially came down to "white" and "nonwhite." Consequently, certain social inequalities were bestowed upon those groups that did not fit the model of the dominant "white" group. Autobiographies, especially those from marginalized groups, can serve as an important source of these social disparities since the author is able to recount their own social experiences vis-à-vis racial practices within society. With this in mind, this thesis analyses the concept of race in relation to the personal experiences of two authors through their respective autobiographies: Hunger of Memory: The Education of Richard Rodriguez (1982) by Richard Rodriguez and How Did You Get to Be Mexican?: A White/Brown Man's Search for Identity (1999) by Kevin R. Johnson. The critical work of Paula M. L. Moya, Linda Martín Alcoff, Hazel Rose Markus, George M. Fredrickson, Genaro M. Padilla and others are used as the theoretical framework in the literary analysis of these authors' texts. In summary, the results of this study demonstrate the concept of race as a salient aspect in regards to the ideological formation of each respective author.Dissertation/ThesisM.A. Spanish 201
The long-wavelength view of GG Tau A: rocks in the ring world
No full textWe present the first detection of GG Tau A at centimetre wavelengths, made with the Arcminute Microkelvin Imager Large Array at a frequency of 16 GHz (λ = 1.8 cm). The source is detected at >6 σrms with an integrated flux density of S16GHz = 249 ± 45 µJy. We use these new centimetre-wave data, in conjunction with additional measurements compiled from the literature, to investigate the long-wavelength tail of the dust emission from this unusual protoplanetary system. We use an MCMC-based method to determine maximum likelihood parameters for a simple parametric spectral model and consider the opacity and mass of the dust contributing to the microwave emission. We derive a dust mass of Md ~ 0.1 Msun, constrain the dimensions of the emitting region and find that the opacity index at λ > 7 mm is less than unity, implying a contribution to the dust population from grains exceeding ~4 cm in size. We suggest that this indicates coagulation within the GG Tau A system has proceeded to the point where dust grains have grown to the size of small rocks with dimensions of a few centimetres. Considering the relatively young age of the GG Tau association in combination with the low derived disc mass, we suggest that this system may provide a useful test case for rapid core accretion planet formation models
Research compendium for "Niche shifts after long-distance dispersal events in bipolar sedges (Carex, Cyperaceae)"
No full text<p>Research compendium (code and data) used for the species distribution modelling analyses in the following journal publication:</p>
<p>Villaverde T, González-Moreno P, Rodríguez-Sánchez F & Escudero M. (2017) Niche shifts after long-distance dispersal events in bipolar sedges (<em>Carex</em>, Cyperaceae). <em>American Journal of Botany</em>.</p>
<p>Compendium URL: https://doi.org/10.5281/zenodo.896787</p>
<p>Author: Francisco Rodriguez-Sanchez ([email protected])</p>
<p> </p>
- …
