Tm3+/Ho3+ codoped tellurite fiber laser

Continuous-wave and Q-switched lasing from a Tm 3+ /Ho 3+ codoped tellurite fiber is reported. An Yb 3+ /Er 3+ -doped silica fiber laser operating at 1.6μm was used as an in-band pump source, exciting the Tm 3+ ions into the F 4 3 level. Energy is then nonradiatively transferred to the upper laser level, the I 7 5 state of Ho 3+ . The laser transition is from the I 7 5 level to the I 8 5 level, and the resulting emission is at 2.1μm . For continuous wave operation, the slope efficiency was 62% and the threshold 0.1W ; the maximum output demonstrated was 0.16W . Mechanical Q switching resulted in a pulse of 0.65μJ energy and 160ns duration at a repetition rate of 19.4kHz

Michael Handelsman: estudioso, archivero y crítico de la prosa literaria escrita por mujeres en Ecuador (Tributo)

This paper intends to recognize and highlight the outstanding input made by critic Michael Handelsman in his study on narrative (both essayistic and fictional) written by women in Ecuador. It is important to highlight the scope of a work committed to place women’s writing in the cultural and political sphere and show its impact on the public and social scene, in the horizon of its production, circulation and reception possibilities. Handelsman’s writings (where he studies essays, novels, short stories and magazines written by Ecuadorian women) are approached with the purpose of observing his reading strategies, which lead him to conceive Literature as a struggle scenario for female writers: a space of self-representation, resistance and production of knowledge, in tension with a system of patriarchal values. Above all, this paper is a tribute to the task continually performed by Michael Handelsman for some decades, with generosity and lucidity, in the search and construction of the corpus that constitutes its object of study. It is a corpus scattered through libraries, archives, magazines, anthologies, which Handelsman has located, attended to, taken care of, systematized, periodized, valued, placed for debate, generated affiliations therewith, always insisting on the existence and scope of the valuable –and sometimes forgotten narrative tradition– produced in Ecuador by female writers.Este trabajo tiene como propósito reconocer y destacar el notable aporte realizado por el crítico Michael Handelsman en el estudio de la narrativa (ensayística y de ficción) escrita por mujeres en Ecuador. Interesa resaltar los alcances de una labor empeñada en situar la escritura de mujeres en el terreno de la esfera cultural y política, de su impacto en la escena pública y social, en el horizonte de sus condiciones de posibilidad de producción, así como de circulación y recepción. Los escritos de Handelsman son atendidos (en los que estudia ensayos, novelas, cuentos y revistas escritas por mujeres ecuatorianas) con el propósito de observar sus estrategias de lectura que lo llevan a pensar la literatura como un escenario de lucha para las mujeres escritoras: espacio de autorepresentación, de resistencia y producción de conocimiento, en tensión con un sistema de valores de origen patriarcal. Sobre todo, este trabajo es un homenaje y tributo a la tarea que Michael Handelsman ha desempeñado de manera sostenida durante algunas décadas, con generosidad y lucidez en la búsqueda y construcción de su corpus objeto de estudio. Un corpus disperso en bibliotecas, archivos, revistas, antologías, que Handelsman ha sabido ubicar, atender, cuidar, sistematizar, periodizar, valorar, poner en debate, generar filiaciones e insistentemente señalar la existencia y alcances de esa valiosa, y a veces olvidada tradición narrativa producida en Ecuador por escritoras mujeres

Analyse de la motivation et du processus décisionnel d'investissement en "crowdfunding"

Avant 2008, la réalité du financement des entreprises et des startups se résumait aux crédits bancaires et à l’aide financière de la famille ou des amis. Mais ça... c’était avant ! Aujourd’hui, l’émergence du financement participatif (« crowdfunding ») leur permet d’élargir leurs sources de financement externe. En effet, elles peuvent à présent obtenir le soutien financier de particuliers (en anglais, « the crowd »). Le principe du « crowdfunding » est simple. Il est inspiré du dicton français : « Les petits ruisseaux font les grandes rivières ». Grâce au financement participatif, les entrepreneurs peuvent récolter de petites sommes d’argent auprès d’un grand nombre de personnes pour financer la réalisation d’un projet. Ce travail va s’intéresser plus spécifiquement au « crowdinvesting », qui permet à des investisseurs d’apporter une contribution financière à un projet et de devenir ainsi actionnaires de l’entreprise qu’ils soutiennent. En outre, le sujet principal concerne les investisseurs, leur intérêt à investir et les critères de décision qu’ils utilisent. La problématique à laquelle j’ai souhaité répondre est : Que recherchent ou qu’attendent ces investisseurs et comment prennent-­ils leurs décisions d’investissement ? Afin de réaliser ce travail, un sondage a été fait auprès de 163 personnes. L’analyse de la motivation des investisseurs a été réalisée grâce au modèle des quatre valeurs de Sweeney et Soutar (2001) : la valeur fonctionnelle et qualité, la valeur monétaire, la valeur émotionnelle et la valeur sociale. Les résultats ont permis de définir différentes variables qui conduisent un investisseur à soutenir un projet par le biais du « crowdinvesting ». En ce qui concerne le processus décisionnel d’investissement, l’analyse a été effectuée grâce aux précédents travaux sur les « Business Angels ». Selon les résultats, ces derniers et les investisseurs en « crowdinvesting » sont similaires sur certains points, et appliquent des critères de décision similaires tout au long de leur processus

Зависимость физико-химических свойств ВТСП-соединений от размера кристаллитов

Керамическим методом с предварительным получением прекурсора синтезированы материалы состава Bi2Sr2Ca1−xLnxCu2Oу (Ln – La, Nd, Y, Ho, Lu) и Bi2Sr2−xLnxCaCu2Oу (Ln – La, Nd, Ho, Lu). Исследованы микроструктура, область гомогенности, электрофизические характеристики, кислородная стехиометрия систем Bi2Sr2Ca1−xLnxCu2Oу (Ln – La, Nd, Y, Ho, Lu) и Bi2Sr2−xLnxCaCu2Oу (Ln – La, Nd, Ho, Lu) в зависимости от степени замещения х и температуры перехода в сверхпроводящее состояние Тсon. Изучено влияние условий термической обработки на размеры кристаллитов, величину кислородного индекса и критическую температуру. Получены наноразмерные частицы (Dср = 0,5—1,5 мкм). Показано, что границы области гомогенности уменьшаются от 0 ≤ x ≤ 0,3 по Lu3+ к 0 ≤ x ≤ 0,05 по La3+.Керамічною методою з попереднім одержанням прекурсору синтезовано матеріяли складу Bi2Sr2Ca1−xLnxCu2Oу (Ln – La, Nd, Y, Ho, Lu) та Bi2Sr2−xLnxCaCu2Oу (Ln – La, Nd, Ho, Lu). Досліджено мікроструктуру, область гомогенности, електрофізичні характеристики й кисневу стехіометрію систем Bi2Sr2Ca1−xLnxCu2Oу (Ln – La, Nd, Y, Ho, Lu) і Bi2Sr2−xLnxCaCu2Oу (Ln – La, Nd, Ho, Lu) залежно від ступеня заміщення х та температури переходу в надпровідний стан Тсon. Вивчено вплив умов термічного оброблення на розмір зерна, величину кисневого індексу та критичну температуру. Одержано нанорозмірні частинки (Dсер = 0,5—0,15 мкм). Показано, що межі гомогенности зменшуються від 0 ≤ x ≤ 0,3 за Lu3+ до 0 ≤ x ≤ 0,05 за La3+.The samples of Bi2Sr2Ca1−xLnxCu2Oу (Ln–La, Nd, Y, Ho, Lu) and Bi2Sr2−xLnxCaCu2Oу (Ln–La, Nd, Ho, Lu) are synthesized using the ceramic technique with precursor. For Bi2Sr2Ca1−xLnxCu2Oy (Ln–La, Nd, Y, Ho, Lu) and Bi2Sr2−xLnxCaCu2Oу (Ln–La, Nd, Ho, Lu) systems, the dependences of microstructure, homogeneity region, electrophysical properties, and oxygen nonstoichiometry on their composition (x) and Tcon value are studied. Influence of heat-treatment conditions on the sizes of crystallites, value of oxygen index, and critical temperature is studied. As shown, the homogeneity region becomes narrower when going from 0 ≤ x ≤ 0.3 for Lu3+ to 0 ≤ x ≤ 0.05 for La3+

La sencilla lucidez de Pedro Jorge Vera. Notas a propósito de su cuentística (Homenaje)

A privileged genre in Latin America, short stories have had, and still have, highly esteemed cultivators in the region such as the late Ecuadorian writer Pedro Jorge Vera, a creator whose birth centennial is celebrated in 2014, on the occasion of which this paper examines some of his most important stories in order to highlight their humanistic and denunciatory will of the social injustices and prejudices suffered by the poorest and least privileged sectors of Latin America. With their lucid simplicity, Vera’s stories stand out for the stylistic organicity of their writing, the broad thematic spectrum and the rich range of narrative procedures which very effectively convey the charges of the stories told. Distinctive features of this manner of proceeding are the fully developed, the rapid progress of the action and compact structure, the unpredictability of their outcomes, the sobriety and accuracy of the narrative discourse, the decisive role of deconstructive procedures and preference for problematic, contradictory characters.Género privilegiado en América Latina, el cuento ha tenido y tiene cultores de alta estima en la región como el desaparecido escritor ecuatoriano Pedro Jorge Vera, creador cuyo centenario de nacimiento se celebra en este 2014, y con motivo del cual el presente ensayo examina algunos de sus cuentos más importantes con el propósito de destacar su definida voluntad humanista y denunciatoria de las injusticias y prejuicios sociales padecidos por los sectores más humildes o menos privilegiados de América Latina. Exponentes de una poética de lúcida sencillez, los cuentos de Vera sobresalen por la organicidad estilística de su escritura, el amplio espectro temático y la rica gama de procedimientos narrativos que vehiculan con suma eficacia los encargos de las historias narradas. Rasgos distintivos de ese proceder son los comienzos en pleno desarrollo, el rápido progreso de la acción y compacta estructura, la imprevisión de sus desenlaces, la sobriedad y precisión del discurso narrativo, el papel decisivo de procedimientos deconstructores y la preferencia por personajes problemáticos, contradictorios

Michael Handelsman, pionero en los estudios de la literatura afroecuatoriana (Tributo)

This article reviews Michael Handelsman’s contributions to studies on Afro-Ecuadorian Literature. Handelsman is a pioneer in the field, and his book published in 1999, Lo afro y la plurinacionalidad: el caso ecuatoriano visto desde su literatura, is the most outstanding contribution and the most careful and profound study regarding the importance of observing, in the turn of the century, the contributions made by Afro-Ecuadorian writers, particularly in a moment in which the debate on pluri-nationality is crucial. The main objective of Handelsman’s book is to think a pluri-national Ecuador from the Afro-Ecuadorian community’s production, and not just from the centrality as traditionally assigned to Indigenous communities. For this, the author will study different literary expressions, from the perception of the Afro subject in the works produced by the Guayaquil Group, going through the works of the most outstanding Afro-Ecuadorian writers of the 20th Century, until reaching the diverse expressions about the Afro, expressed in cultural magazines throughout the past century.Este artículo revisa los aportes de Michael Handelsman a los estudios de la literatura afroecuatoriana. Handelsman es un pionero en el campo y su libro de 1999, Lo afro y la plurinacionalidad: el caso ecuatoriano visto desde su literatura, es el mayor aporte y el estudio más cuidadoso y profundo respecto de la importancia de observar, en el giro del siglo, los aportes de escritores afro en nuestro país, particularmente en un momento en el que el debate en torno a la plurinacionalidad es central. El objetivo principal del libro de Handelsman es pensar un Ecuador plurinacional desde el aporte de la comunidad afro y no solo desde la centralidad tradicionalmente otorgada a las comunidades indígenas. Para esto, el autor estudiará diferentes expresiones literarias, desde la percepción del sujeto afro en la literatura del Grupo de Guayaquil, pasando por la obra de los mayores escritores afroecuatorianos del siglo XX, hasta las diferentes expresiones sobre lo afro vertidas en revistas culturales a lo largo del siglo pasado

Determination of morphological, phenological pomological characteristics in some jujube genotypes and investigation of hybridization possibilities

Bu çalışma Aydin ili Kızılcaköy’deki bir meyve bahçesinde 2012 ve 2013 yıllarında yürütülmüştür. Küçük (HK), orta (HO) ve büyük (HB) meyveli olmak üzere üç farklı hünnap (Ziziphus jujuba Mill.) genotipi kullanılmıştır. Morfolojik ölçüm değerleri şu şekildedir: ağaç boyu 4.0 m (HK)-5.7 m(HB), gövde çevresi 26 cm (HO)-36 cm (HB), çapı 8.3 cm (HO)-11.5 cm (HB); kök sürgününün ana gövdeye mesafesi 5.8 m (HK)-8.0 m (HB) ve boyu 56.3 cm (HO)-62.2 cm (HB); bir yaşlı dalın uzunluğu 46.00 cm (HK)-86.50 cm (HO), çapı 5.00 cm (HK)-12.32 cm (HO) ve sayısı 5.67 adet (HK)-10.50 adet (HO); yan sürgün uzunluğu 23.85 cm (HK)-28.94 cm (HB) ve çapı 4.61 cm (HK)-5.02 cm (HB), yaprak sayısı 4.00 adet (HK)-6.47 (HO), diken sayısı 1.70 adet (HB)-2.00 (HK ve HO); yaprak uzunluğu 6.81 cm (HB)-18.20 cm (HK), çapı 1.54 cm (HB)-1.73 cm HO, yaprakçık sayısı 4.42 adet (HB)-14.46 adet (HK); yaprakçık uzunluğu 32.79 mm (HK)-47.20 mm (HB) ve eni 17.46 mm (HK)-27.05 mm (HB), kalınlığı 0.23 mm (HB)-0.59 mm (HO); koltuk yaprağı uzunluğu 51.27 cm (HO)-62.39 cm (HB) ve eni 30.94 cm (HO)-34.36 mm (HB), kalınlığı 0.28 mm (HB)-0.31 mm (HO); boğumdaki diken sayısı 0.16 adet (HK)-1.70 adet (HO); kapalı çiçek tomurcuğu boyu 1.55 mm (HK)-2.03 mm (HO), eni 2.36 mm (HK)-3.49 mm (HB); açmış çiçek boyu 1.60 cm (HK)-2.60 mm (HB), eni 5.51 mm (HK)-7.21 mm (HB). Yaprakların üst ve alt yüzeylerindeki klorofil miktarı hünnap genotiplerinde (58.50 (HO)-69.82 (HK)) farklı olmamıştır. Fenolojik gözlemlerden çiçeklenme 30 Nisan ile 09 Temmuz 2012 tarihleri arasında oluşmuştur. 20 Ağustos 2013 ben düşme tarihidir. Pomolojik gözlemlerden meyve eni 24.02 mm (HK)-37.35 mm (HB), boyu 29.47 mm (HK)-43.73 mm (HB) ve ağırlığı 8.21 g (HK)-28.85 g (HB) arasındadır. Meyve eti sertliği (3.49 (HK)-3.89 (HO)), L, a, b renk değerleri, SÇKM (25.73 (HB)-32.00 (HK)), TA (11.57 (HB)-12.13 (HO)), pH (4.64 (HO ve HB)-4.87 (HK)) hünnap genotipleri arasında farklı olmamıştır. Panelistlere göre meyvenin tadı elmaya benzemektedir. Tohum eni 8.18 mm (HK)-9.43 mm (HO) ve boyu 15.99 mm (HK)- 25.38 mm (H O), ağırlığı 0.68 g (HK)-1.16 g (HB)’dir. Tek yıllık sürgün üzerinde tomurcuk, çiçek ve meyve aynı anda gözlenebilmektedir. Hünnabın bir çiçekteki başçık sayısı tüm genotiplerde 5 adettir. Bir başçıktaki çiçek tozu sayısı 171.85 adet (HO)-760.00 adet (HK), bir çiçekteki çiçek tozu sayısı 859.25 (HO)-3800.00 adet (HK) arasında değişmiştir. Üç genotipte yapılan çiçek tozu IKI canlılık testinde 2012’de %85.59 (HK)-%92.26 (HB), 2013’te %64.94 (HO)-%89.78 (HB) değerleri bulunmuştur.. Çiçek tozu çimlendirme testine göre %1 agar+%15 sakkaroz besi ortamında çimlenme değerleri %1.92 (HO)-%24.48 (HB) arasında elde edilmiştir. 2012’de üç hünnap genotipindeki açık tozlama gözleminde meyve tutumu %18.81 (HO)-%42.39 (HB) arasında bulunmuştur. 2013 yılı HB × HK karşılıklı tozlaması sonucu 6 adet melez meyve oluşmuştur.This study was conducted in a fruit orchard located in Kızılcaköy, Aydın in 2012 and 2013. There are three different fruit size, namely small (HK), medium (HO) and large (HB), jujube (Ziziphus jujuba Mill.) genotypes were used. For morphological observations, the values were as follows: tree height 4.0 m (HK)-5.7 m(HB), circumference 26 cm (HO)-36 cm (HB), diameter 8.3 cm (HO)-11.5 cm (HB); root sucker distance 5.8 m (HK)-8.0 m (HB) and 56.3 cm (HO)-62.2 cm (HB); one-year-old branch length 46.00 cm (HK)-86.50 cm (HO), diameter 5.00 cm (HK)-12.32 cm (HO), and number 5.67 adet (HK)-10.50 adet (HO); side shoot length 23.85 cm (HK)-28.94 cm (HB) and diameter 4.61 cm (HK)-5.02 cm (HB), leaf number 4.00 adet (HK)-6.47 (HO), and thorn number 1.70 adet (HB)-2.00 (HK ve HO); leaf length 6.81 cm (HB)-18.20 cm (HK), diameter 1.54 cm (HB)-1.73 cm HO, and leaflet number 4.42 adet (HB)-14.46 adet (HK); leaflet length 32.79 mm (HK)-47.20 mm (HB) and width 17.46 mm (HK)-27.05 mm (HB), and thickness 0.23 mm (HB)-0.59 mm (HO); axillary leaf length 51.27 cm (HO)-62.39 cm (HB) and width 30.94 cm (HO)-34.36 mm (HB), and thickness 0.28 mm (HB)-0.31 mm (HO); thorn number at the node 0.16 adet (HK)-1.70 adet (HO); closed flower bud height 1.55 mm (HK)-2.03 mm (HO), width 2.36 mm (HK)-3.49 mm (HB); open flower height 1.60 cm (HK)-2.60 mm (HB), width 5.51 mm (HK)-7.21 mm (HB); Chlorophyll amounts in upper- and lower-side of leaves did not differ in different jujube genotypes (58.50 (HO)-69.82 (HK)). For phenological observations, flowering occurred between 30 April and 09 July in 2012. Veraison date was 20 August 2013. For pomological measurements, the fruit values are as follows: width 24.02 mm (HK)-37.35 mm (HB), length 29.47 mm (HK)-43.73 mm (HB), and weigth 8.21 g (HK)-28.85 g (HB). Fruit firmness (3.49 (HK)-3.89 (HO)), L, a, b values, TSS (25.73 (HB)-32.00 (HK)), TA (11.57 (HB)-12.13 (HO)), pH (4.64 (HO ve HB)-4.87 (HK)) did not significantly different among jujube genotypes. The taste of the fruit resembles to apple according to panelists. The values for seeds were width 8.18 mm (HK)-9.43 mm (HO) and length 15.99 mm (HK)-25.38 mm (HO), and weigth 0.68 g (HK)-1.16 g (HB). The flower buds, fowers, and fruit can be observed at the same time on the tree. The number of anthers per flower is five in three jujube genotypes. The number of pollens per anther was changed 171.85 (HO)-760.00 (HK) and that of per flower was changed 859.25 (HO)-3800.00 (HK). The pollen viability with IKI test was 85.59% (HK)-92.26% (HB) in 2012 and 64.94% (HO)-89.78% (HB) in 2013. The highest pollen germination was obtained as 1.92% (HO)-24.48% (HB) with 1% agar+15% saccharose. In open-pollination, fruit set was found 18.81% (HO)-42.39% (HB) in 2012 in three jujube genotypes. In HB × HK hybrid combination, six fruit were obtained

A Michael Handelsman: pensador-hacedor-escritor de afán intercultural y decolonial (Tributo)

This letter to Michael Handelsman is an exercise of reflection in which Catherine Walsh writes “co(n)versifying and co-thinking” with said author. The clear purpose is to remember and highlight the literary, intercultural and de-colonial task carried out by Handelsman, with relation to his work as a scholar devoted to Ecuadorian Literature, particularly, Afro-Ecuadorian, without having left aside –despite adopting the aforementioned point of view–, a reading of culture and society as a whole. Walsh’s words arise from a strong critic against literate power and a declared “personal-political-intellectual” empathy with her interlocutor, as privileged places of expression.Esta carta dirigida a Michael Handelsman es un ejercicio de reflexión en el que Catherine Walsh escribe “con-versando y co-pensando” con el explícito propósito de recordar y destacar la labor literaria, intercultural y decolonial de Handelsman, en relación a su labor como estudioso de la literatura ecuatoriana, de manera particular afro-ecuatoriana, cuya mirada afrocentrada no ha dejado de leer, desde ese lugar, la cultura y la sociedad en su conjunto. Las palabras de Walsh se entretejen desde una rotunda crítica al poder letrado y una declarada empatía afectiva “personal-político-intelectual” con su interlocutor, como lugares privilegiados de enunciación

Development of flashlamp-pumped Q-switched Ho:Tm:Cr:YAG lasers for mid-infrared LIDAR application

A flashlamp-pumped 2.1 micron Ho:Tm:Cr:YAG laser was studied for both normal mode and Q-switched operations under a wide variety of experimental conditions in order to optimize performance. Laser output energy, slope efficiency, threshold and pulselength were determined as a function of operating temperature, output mirror reflectivity, input electrical energy and Q-switch opening time. The measured normal-mode laser thresholds of a Ho(3+) (0.45 atomic percent):Tm(3+) (2.5 atomic percent):Cr(3+) (0.8 atomic percent):YAG crystal ranged form 26 to 50 J between 120 and 200 K with slope efficiencies up to 0.36 percent with a 60 percent reflective output mirror. Under Q-switched operation the slope efficiency was 90 percent of the normal-mode result. Development of solid state lasers with Ho(3+), Tm(3+) and/or Er(3+) doped crystals has been pursued by NASA for eye-dafe mid-infrared LIDAR (light detection and ranging) application. As a part of the project, the authors have been working on evaluating Ho(3+):Tm(3+):Cr(3+):YAG crystals for normal-mode and Q-switched 2.1 micron laser operations in order to determine an optimum Tm(3+) concentration under flashlamp pumping conditions. Lasing properties of the Ho(3+) in the mid-infrared region have been studied by many research groups since the early 1960's. However, the technology of those lasers is still premature for lidar application. In order to overcome the inefficiency related to narrow absorption bands of the Ho(3+), Tm(3+) and Er(3+), the erbium has been replaced by chromium. The improvement in flashlamp-pumped Ho(3+) laser efficiency has been demonstrated recently by several research groups by utilizing the broad absorption spectrum of Cr(3+) which covers the flashlamp's emission spectrum. Efficient energy transfer to the Tm(3+) and then the Ho(3+) occurs subsequently. It is known that high Tm(3+) concentration and low Ho(3+) concentration are preferred to achieve a quantum efficiency approaching two and to avoid large reabsorption losses. However, determination of the optimum Tm(3+) concentration required to ensure efficient energy transfer from Cr(3+) to Tm(3+) and from Tm(3+) to Ho(3+) has not been made in the Ho:Tm:CR:YAG crystal. The results obtained so far are given