Determinantes de la eficiencia en el canal de distribución: análisis en agencias de viajes

El incremento de la competencia entre agencias de viajes y el impacto del comercio electrónico como una alternativa al canal de distribución turístico tradicional han dado lugar a un entorno en el que la gestión eficiente de los recursos productivos resulta fundamental para las agencias de viajes. Así, el objetivo del trabajo consiste en estimar la eficiencia con la que operan los intermediarios del sector minorista español de distribución turístico, y conocer la influencia de algunos de sus factores determinantes (salarios, antigüedad y oferta de servicios de comercio electrónico). La metodología de investigación se apoya en la estimación de una frontera paramétrica de naturaleza estocástica. El análisis empírico efectuado sobre una muestra de 1086 agencias de viajes en 2004 evidencia bajos niveles de eficiencia, que son explicados por el nivel de salarios medio y por la antigüedad de la agencia.

El sur también existe: las relaciones migratorias entre las islas Baleares y la Argelia francesa (1830-1962)

La Argelia francesa (1830-1962) constituyó un poderoso polo de atracción para los habitantes de las islas Baleares y del sudeste peninsular. En este artículo se analizan las relaciones migratorias y comerciales entre el archipiélago balear y su por entonces próspero vecino del sur. Además, también se estudian los diferentes exilios que vincularon las dos riberas del Mediterráneo. Para realizar este artículo se han combinado tanto fuentes primarias como la bibliografía existente.

A new boundary-based morphological model

Mathematical morphology addresses the problem of describing shapes in an n-dimensional space using the concepts of set theory. A series of standardized morphological operations are defined, and they are applied to the shapes to transform them using another shape called the structuring element. In an industrial environment, the process of manufacturing a piece is based on the manipulation of a primitive object via contact with a tool that transforms the object progressively to obtain the desired design. The analogy with the morphological operation of erosion is obvious. Nevertheless, few references about the relation between the morphological operations and the process of design and manufacturing can be found. The non-deterministic nature of classic mathematical morphology makes it very difficult to adapt their basic operations to the dynamics of concepts such as the ordered trajectory. A new geometric model is presented, inspired by the classic morphological paradigm, which can define objects and apply morphological operations that transform these objects. The model specializes in classic morphological operations, providing them with the determinism inherent in dynamic processes that require an order of application, as is the case for designing and manufacturing objects in professional computer-aided design and manufacturing (CAD/CAM) environments. The operators are boundary-based so that only the points in the frontier are handled. As a consequence, the process is more efficient and more suitable for use in CAD/CAM systems.

Afghanistan-Pakistan Border Region, 1897 (Raster Image)

This layer is a georeferenced raster image of the historic paper map entitled: W. & A.K. Johnston's war map of the Northwest Indian frontier. It was published by W. & A.K. Johnston in 1897. Scale [ca.1:430,000]. Covers the Afghanistan-Pakistan border region.The image inside the map neatline is georeferenced to the surface of the earth and fit to the Asia North Lambert Conformal Conic coordinate system. All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows features such as drainage, roads, railroads, cities and other human settlements, administrative and territorial boundaries, and more. Shows contested border region and areas of active hostilities. Relief shown by shading. Includes also inset maps: British Baluchistan -- India.This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.

Free State Region, South Africa, 1899 (Raster Image)

This layer is a georeferenced raster image of the historic paper map entitled: Stanford's new map of the Orange Free State, the southern part of the South African Republic, the northern frontier of Cape Colony, Natal, Basutoland and Delagoa Bay. It was published by E. Stanford in 1899. Scale 1:1,000,000 The image inside the map neatline is georeferenced to the surface of the earth and fit to the Africa Lambert Conformal Conic projected coordinate system. All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows features such as drainage, cities and other human settlements, roads, railroads and stations, administrative and territorial boundaries, shoreline features, and more. Relief shown by shading and spot heights.This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.

Eastern Turkistan

specially prepared for the Foreign Department, from India ; published under direction of Colonel F. B. Longe, R. E., Surveyor General of India.

Esperanto for histones: CENP-A, not CenH3, is the centromeric histone H3 variant

The first centromeric protein identified in any species was CENP-A, a divergent member of the histone H3 family that was recognised by autoantibodies from patients with scleroderma-spectrum disease. It has recently been suggested to rename this protein CenH3. Here, we argue that the original name should be maintained both because it is the basis of a long established nomenclature for centromere proteins and because it avoids confusion due to the presence of canonical histone H3 at centromeres.

Polo-like kinase 4 controls centriole duplication but does not directly regulate cytokinesis

Centrioles organize the centrosome, and accurate control of their number is critical for the maintenance of genomic integrity. Centrioles duplicate once per cell cycle, and duplication is coordinated by Polo-like kinase 4 (Plk4). We previously demonstrated that Plk4 accumulation is autoregulated by its own kinase activity. However, loss of heterozygosity of Plk4 in mouse embryonic fibroblasts has been proposed to cause cytokinesis failure as a primary event, leading to centrosome amplification and gross chromosomal abnormalities. Using targeted gene disruption, we show that human epithelial cells with one inactivated Plk4 allele undergo neither cytokinesis failure nor increase in centrosome amplification. Plk4 is shown to localize exclusively at the centrosome, with none in the spindle midbody. Substantial depletion of Plk4 by small interfering RNA leads to loss of centrioles and subsequent spindle defects that lead to a modest increase in the rate of cytokinesis failure. Therefore, Plk4 is a centriole-localized kinase that does not directly regulate cytokinesis.

Highly dynamic host actin reorganization around developing Plasmodium inside hepatocytes

Plasmodium sporozoites are transmitted by Anopheles mosquitoes and infect hepatocytes, where a single sporozoite replicates into thousands of merozoites inside a parasitophorous vacuole. The nature of the Plasmodium-host cell interface, as well as the interactions occurring between these two organisms, remains largely unknown. Here we show that highly dynamic hepatocyte actin reorganization events occur around developing Plasmodium berghei parasites inside human hepatoma cells. Actin reorganization is most prominent between 10 to 16 hours post infection and depends on the actin severing and capping protein, gelsolin. Live cell imaging studies also suggest that the hepatocyte cytoskeleton may contribute to parasite elimination during Plasmodium development in the liver.

The trail drivers of Texas : interesting sketches of early cowboys and their experiences on the range and on the trail during the days that tried men's souls: true narratives related by real cow-punchers and men who fathered the cattle industry in Texas /

Mode of access: Internet.

Davy Crockett, American comic legend,

Aids personal and bibliographical: A word on the almanacs: Notes to frontier humor and legend, p. 164-171.

Davy Crockett, American comic legend;

Anecdotes and woocuts selected from the Crockett almanacs (1835-1856) cf. Editors̓ note.

Adventures in error,

"Errata" slip inserted.

Early days of the Lake Superior copper country.

Mode of access: Internet.

The birth of Yugoslavia,

"Portions of this book which deal with Yugoslav-Albanian affairs have appeared in the Fortnightly review and, expanded from there, in a volume entitled A difficult frontier.