Quaternary E-W Extension Uplifts Kythira Island and Segments the Hellenic Arc.

Several crustal and lithospheric mechanisms lead to deformation and vertical motion of the upper plate during subduction, but their relative contribution is often enigmatic. Multiple areas of the Hellenic Forearc have been uplifting since Plio-Quaternary times, yet spatiotemporal characteristics and sources of this uplift are poorly resolved. The remarkable geology and geomorphology of Kythira Island, in the southwestern Hellenic forearc, allow for a detailed tectonic reconstruction since the Late Miocene. We present a morphotectonic map of the island, together with new biostratigraphic dating and detailed analyses of active fault strikes and marine terraces. We find that the Tortonian-Pliocene stratigraphy in Kythira records ∼100 m of subsidence, and a wide coastal rasa marks the ∼2.8-2.4 Ma maximum transgression. Subsequent marine regression of ∼300-400 m and minor E-W tilt are recorded in ∼12 marine terrace levels for which we estimate uplift rates of ∼0.2-0.4 mm/yr. Guided by simple landscape evolution models, we interpret the coastal morphology as the result of initial stability or of slow, gradual sea-level drop since ∼2.8-2.4 Ma, followed by faster uplift since ∼1.5-0.7 Ma. Our findings on- and offshore suggest that E-W extension is the dominant mode of regional active upper crustal deformation, and N-S normal faults accommodate most, if not all of the uplift on Kythira. We interpret the initiation of E-W extension as the result of a change in plate boundary conditions, in response to either propagation of the North Anatolian Fault, incipient collision with the African plate, mantle dynamics or a combination thereof.

Lithospheric flexure and rheology determined by climate cycle markers in the Corinth Rift.

Geomorphic strain markers accumulating the effects of many earthquake cycles help to constrain the mechanical behaviour of continental rift systems as well as the related seismic hazards. In the Corinth Rift (Greece), the unique record of onshore and offshore markers of Pleistocene ~100-ka climate cycles provides an outstanding possibility to constrain rift mechanics over a range of timescales. Here we use high-resolution topography to analyse the 3D geometry of a sequence of Pleistocene emerged marine terraces associated with flexural rift-flank uplift. We integrate this onshore dataset with offshore seismic data to provide a synoptic view of the flexural deformation across the rift. This allows us to derive an average slip rate of 4.5-9.0 mm·yr-1 on the master fault over the past ~610 ka and an uplift/subsidence ratio of 1:1.1-2.4. We reproduce the observed flexure patterns, using 3 and 5-layered lithospheric scale finite element models. Modelling results imply that the observed elastic flexure is produced by coseismic slip along 40-60° planar normal faults in the elastic upper crust, followed by postseismic viscous relaxation occurring within the basal lower crust or upper mantle. We suggest that such a mechanism may typify rapid localised extension of continental lithosphere.

Curso de epidemiología

Este documento de autoría del Dr. Rolando Armijo Rojas, corresponde a la 2a. edición, publicada en el año 1964. En el marco del Proyecto "Biblioteca Digital" de la Universidad de Chile, el libro fue editado en formato electrónico. Los capítulos contenidos son:I.Principios de la epidemiología. II.Las enfermedades transmisibles. III.Enfermedades que se propagan por vía respiratoria. IV.Poliomielitis. V.Enfermedades que se propagan por vía digestiva. VI. Enfermedades que se propagan por contacto directo. VII.Enfermedades transmitidas por artropodos. VIII.Infecciones intrahospitalarias estafilococicas. IX.Tuberculosis. X.Zoonosis. XI. Epidemiología de algunas condiciones no infecciosas. XII.Investigación e informe de epidemias. XIII.Intoxicaciones e infecciones alimentarias. XIV.Evaluación de vacunas. XV.Administración de programas de epidemiología.

Prevalencia de portadores tíficos después del tratamiento con cloramfenicol / Prevalence of typhoid carriers after treatment with choramphenicol

A study of 460 female patients who had been diagnosed as typhoid fever cases and dismissed from the "Hospital de Infecciosos" in Santiago, Chile, during the period 1960-1064 was made for the purpose of determining the rate of Salmonella typhi carriers among them. All of the patients had been treated with chloranphenicol during the acute stage of the disease

Over a two-year period more than 3,000 home visits and nearly 2,000 fecal cultures were made to detect carriers among both the index cases and their suspect contacts. Thirty-four carriers (7.4 per cent) of a minimum duration of two years and an average of 3.7 years' duration were detected and another eight carriers were found among the contacts

Attention is drown to the following associations: the ratio of carriers increases with age and depending on the length of time elapsed between the first sypmptoms and treatment; the ratio is significantly higher when there has been a relapse; there is observable association between being a carrier and the presence of liver disorders

The rate of typhoid fever among contacts exposed to a proven carrier was five times higher than among the families in which no carrier was detected(AU)

Prevalence of typhoid carriers after treatment with chloramphenicol

Now many typhoid fever patients who have been treated with chloramphenicol during the acute phase of their illness remain carriers of Salmonella typhi after their release? A study in Chile identified 7.4 per cent of such cases and made it possible to suggest factors of possible etiological significance.

El problema del aborto provocado en Chile / The problem of induced abortion in Chile

The incidence of induced abortion in Chile, especially among women from 20 to 44 years of age, is well known. On the basis of the 1960 census, the authors obtained random samples from three representative areas in the country: one from the urban population of Santiago, another from Antofagasta, and the third from the Province of Concepción. Through home visits, data relating to abortion were obtained from 3,926 women. After examining and comparing these data from various points of view, the authors conclude that the epidemiological situation with respect to induced abortions in Chile requires urgent preventive measures. There are susceptible groups - such as those 20 to 34 years of age and a small proportion of women with a history of repeated abortions - which amount to a thrid of the total cases examined. The incidence is high among married women, among women with up to three living children, and among those with low incomes. The majority of abortions are performed by non-qualified persons and methods used are dangerous. The authors conclude that contraceptive measures should replace induced abortions

El problema del aborto provocado en Chile / The problem of induced abortion in Chile

The incidence of induced abortion in Chile, especially among women from 20 to 44 years of age, is well known. On the basis of the 1960 census, the authors obtained random samples from three representative areas in the country: one from the urban population of Santiago, another from Antofagasta, and the third from the Province of Concepción. Through home visits, data relating to abortion were obtained from 3,926 women. After examining and comparing these data from various points of view, the authors conclude that the epidemiological situation with respect to induced abortions in Chile requires urgent preventive measures. There are susceptible groups - such as those 20 to 34 years of age and a small proportion of women with a history of repeated abortions - which amount to a thrid of the total cases examined. The incidence is high among married women, among women with up to three living children, and among those with low incomes. The majority of abortions are performed by non-qualified persons and methods used are dangerous. The authors conclude that contraceptive measures should replace induced abortions

Prevalencia de portadores tíficos después del tratamiento con cloramfenicol / Prevalence of typhoid carriers after treatment with choramphenicol

A study of 460 female patients who had been diagnosed as typhoid fever cases and dismissed from the "Hospital de Infecciosos" in Santiago, Chile, during the period 1960-1064 was made for the purpose of determining the rate of Salmonella typhi carriers among them. All of the patients had been treated with chloranphenicol during the acute stage of the disease

Over a two-year period more than 3,000 home visits and nearly 2,000 fecal cultures were made to detect carriers among both the index cases and their suspect contacts. Thirty-four carriers (7.4 per cent) of a minimum duration of two years and an average of 3.7 years' duration were detected and another eight carriers were found among the contacts

Attention is drown to the following associations: the ratio of carriers increases with age and depending on the length of time elapsed between the first sypmptoms and treatment; the ratio is significantly higher when there has been a relapse; there is observable association between being a carrier and the presence of liver disorders

The rate of typhoid fever among contacts exposed to a proven carrier was five times higher than among the families in which no carrier was detected(AU)