Seismically-induced landslides by a low-magnitude earthquake: The Mw 4.7 Ossa De Montiel event (central Spain)

The Ossa de Montiel (2015/02/23, Mw 4.7) earthquake struck the central part of Spain and was felt far from the epicenter (> 300 km). Even though ground shaking was slight (Imax = V, EMS-98 scale), the earthquake triggered many small rock falls, most at distances of 20–30 km from the epicenter, greater than previously recorded in S Spain (16 km) for earthquakes of similar magnitudes. The comparative analysis of available data for this event with records from other quakes of the Betic cordillera (S and SE Spain) seems to indicate a slower pattern of ground-motion attenuation in central Spain. This could explain why slope instabilities occurred at larger distances. Instability was more frequent, and occurred at larger distances, in road cuts than in natural slopes, implying that such slope types are highly susceptible to seismically induced landslides.This work has been funded by Spanish Ministry of Economy and Competitiveness, research project CGL2011-30153-C02-02, and by the research groups RNM-374 (Junta de Andalucía), TECTAC (UCM-910368) and VIGROB-184 (Universidad de Alicante). Mr. Loffredo acknowledges funding of the Università di Roma — La Sapienza (post-graduate grant) (Concorso A N.480 - Area CUN 04)

Visual dysfunction in patients with mitochondrial myopathies. I. Electrophysiologic impairments.

Seventeen patients with biopsy-confirmed mitochondrial progressive external ophthalmoplegia underwent electroretinography and visual evoked potential testing to checkerboard-reversal stimuli to investigate subclinical visual dysfunction. Seven patients (41%) had impaired Snellen visual acuity that was never less than 0.6. Thirteen patients (76%) showed electroretinographic and/or visual evoked potential alterations, whereas six (35%) showed impairment on both tests. Two patients showed delayed VEP P100 latency without fundus, electroretinographic or visual acuity anomalies. Visual dysfunctions were not related to age at onset and course of the disease

Stevens-Johnson syndrome: a clinical and histological study.

A description is given of a case of Stevens-Johnson syndrome clinically and histologically ascertained in a middle-aged male with typical localization and later chronicity of the ocular involvement. Besides, an outline is drawn of its clinical picture and of the etiopathogenetical hypothesis, dwelling upon the allergic hypothesis though not excluding the iatrogenic one

Analysis of foveation duration and repeatability at different gaze positions in patients affected by congenital nystagmus.

Congenital nystagmus (CN) is a disturbance of the oculomotor centers which develops at birth or in the first months of life. Nystagmus consists essentially in involuntary, conjugated, horizontal rhythmic movements of the eye. Its pathogenesis is still unknown. Current therapies for CN aim to increase the patient’s visual acuity by means of refraction defects correction, drug delivery and ocular muscle surgery. Eye movement recording supports for accurate diagnosis, for patient follow-up and for therapy evaluation. In general, CN patients show a considerable decrease of visual acuity (image fixation on the retina is obstructed by nystagmus continuous oscillations) and severe postural alterations such as the anomalous head position, searched by patient to obtain a better fixation of the target image onto the retina. Often CN presents ‘neutral zones’ corresponding to particular gaze angles, in which nystagmus amplitude minimizes allowing a longer foveation time and a more stable repositioning of foveations, increasing visual acuity. Selected patients’ eye movements were recorded by using EOG or infrared oculography devices. Visual stimulation was delivered by means of an arched LED bar covering a visual field of –30 +30 degrees with respect to the central position. Computation of CN concise parameters allows in-dept analysis of foveations and estimation of visual acuity at different gaze angles. Preliminary results show a maximum of visual acuity at a specific gaze angle; this angle is mostly located at the patient’s right side for the analyzed group

Geological risks in large cities: The landslides triggered in the city of Rome (Italy) by the rainfall of 31 January-2 February 2014

An exceptional rainfall battered the city of Rome (Italy) from 31 January to 2 February 2014. The event had variable intensity and duration in the different parts of the city. The exceptionality of the event lies in the intensity of rainfall cumulated in 6 hours (return period > 50 years) and in its uneven distribution over the urban area. The event triggered a number of landslides of different type, which caused substantial damage. Researchers from the Centro di Ricerca per i Rischi Geologici (Research Centre on Prediction, Prevention and Control of Geological Risks - CERI) of the University of Rome "Sapienza" carried out field surveys and assessments immediately after the event. The team detected and inventoried 68 landslides, mostly occurring in the sandy and sandy-silty deposits of the Monte Mario, Ponte Galeria and Valle Giulia Formations. The complete inventory of the landslides is accessible via WebGIS on CERI's website http://www.ceri.uniroma1.it/cn/landslidesroma.jsp. The spatial distribution of the landslides evidences that 69% occurred in clastic deposits of sedimentary origin and only 6% in volcanic deposits. This finding disagrees with more general statistical data, based on the inventory of Rome's historical landslides, indicating that almost 41% of slope instabilities occur in volcanic deposits and almost 12% in sedimentary ones. In the data reported here, this apparent contradiction is justified by the fact that most the rainfall under review was concentrated in the north-western portion of Rome's urban area, whose hills accommodate outcrops of dominantly sedimentary deposits from Plio-Pleistocene marine and continental cycles. © Sapienza Università Editrice