Introduction: unmarried and unknown: urban men and women in the low countries since the early modern period

This essay introduces a special issue on The Lure of the City that examines the attraction of towns to unmarried men and women in the Low Countries during the early modern period and the nineteenth century. The issue has the relation between singles and cities as its main focus. Singles were present in disproportionately large numbers in urban areas, but the question is why? This essay sets out the historiographical framework for the contributions in the issue, discusses the sources and methodologies used, and provides a brief overview of the evolution of singleness in the Low Countries. The contributions all demonstrate the relevance of a comparative approach. It is revealed that towns and cities not only attracted but also created singles, that they offered different opportunities for different groups of unmarried people and that they affected men and women differently. Finally, it appears that not every town and city was attractive to men and women without a spouse

Stadsgeschiedenis in buitenlandse tijdschriften (2018)

Cities, Migration and Global Interdependenc

Micropropagación de plantas de lechosa en recipientes de inmersión temporal a partir de brotes axilares Micropropagation of papaya plants in temporary immersion recipients from axilary shoots

Título en ingles: Micropropagation of papaya plants in temporary immersion recipients from axilary shootsTítulo corto: Micropropagación de lechosa en recipientes de inmersión temporal.Resumen: Se estandarizaron las condiciones de iniciación, multiplicación, enraizamiento y aclimatización de plantas hermafroditas de lechosa cv Maradol provenientes de brotes axilares, producidos en recipientes de inmersión temporal RITA®. En cada envase, contentivo de 200 ml de medio de cultivo líquido de Fitch, se colocaron cuatro brotes de 2 a 3 cm de longitud. Los biorreactores se conectaron a tres líneas de inmersión de 5, 2 y 1 min cada 4h y se colocaron 6 envases en promedio por línea, en condiciones de fotoperíodo de 16 h. Transcurridos 30 a 45 días, se cuantificaron los brotes y se clasificaron de acuerdo al tamaño: 2 cm (pequeños), entre 2 a 3 cm (medianos),  ˃ 3 cm con y sin raíz (grandes). Los dos primeros tipos de brotes se continuaron multiplicando en los mismos medios; y los más elongados se aclimatizaron utilizando el Sistema Autotrófico Hidropónico (SAH). Se determinó la sanidad y la fidelidad de las plantas producidas mediante pruebas de ELISA y RAPD, respectivamente. Durante un periodo de 6 meses se reciclaron un total de 47 recipientes, los cuales produjeron 1.091 brotes: 377  pequeños; 482 medianos; 175 grandes sin raíz y 57 con raíz. Usando el SAH se obtuvo 89,5% de plantas aclimatizadas cuando se usaron brotes enraizados, y 41,6% a partir de brotes sin  raíces. Con la combinación de las técnicas RITA y SAH se logró un sistema continuo y eficiente de producción de plantas sanas y fieles al tipo, en comparación con los métodos convencionales de micropropagación y aclimatización.Palabras clave: Carica papaya, RITA®, sistema autotrófico, estabilidad genética.Key words: Carica papaya, RITA®, autotrophic system, genetic stability.Recibido: mayo 16 de 2014   Aprobado: abril 21 de 2015We standardized initiation, multiplication, rooting and acclimatization conditions of papaya cv Maradol hermaphrodite plants from axillary buds produced in temporary immersion reactor RITA®. Recipients contained 200 ml of Fitch liquid culture medium, and four shoots of 2 to 3 cm. in length were placed in each. The bioreactors were connected to three different immersion lines of 5, 2, and 1 min each 4h, with 6 containers per line on average, in 16 h photoperiod. After 30 to 45 days, the shoots produced were quantified and classified according to size: 2 cm (small), from 2 to 3 cm (medium), 3 cm with or without roots (large). The first two types of shoots were multiplied in the same culture media, and more elongated shoots were acclimatized using Autotrophic Hydroponic System (AHS). The sanity and fidelity of the produced plants were determined using ELISA and RAPD, respectively. For a period of six months 47 vessels were recycled and 1,091 shoots were produced: 377 small; 482 medium; 175 large without roots and 57 rooted shoots. Using AHS, 89.5% acclimatized plants were obtained when rooted shoots were used, and 41.6% from rootless shoots. With the combination of RITA and AHS techniques we achieved a continuous and efficient production of healthy and true to type papaya plants, in comparison to conventional micropropagation and acclimatization procedures.Key words: Carica papaya, RITA®, autotrophic system, genetic stability