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S U M M A R Y An 80 km long reversed seismic refraction line (Line 5) was shot over the Tagus Abyssal Plain off Portugal. The main P-wave reflected and refracted phases were modelled both for traveltime and amplitude. The resulting P-wave velocity/depth model has the following features: (a) an extremely thin crust of about 2 km; (b) the absence of oceanic layer 3; and (c) very low upper mantle velocities between 7.6 and 7.9 km s-'. This very unusual seismic velocity crustal structure is quite unlike thinned continental crust but is remarkably similar to the seismic crustal structures found at Atlantic fracture zones, and in particular to the structures found in profiles shot along the transform valley and near ridge-transform intersections. A magnetic anomaly chart seems to allow the possibility of several fracture zones one of which could intersect the centre of Line 5.As an alternative to the fracture zone hypothesis we show that if the oceancontinent transition in the Tagus Abyssal Plain is located at about 11"30'W, in a symmetric position with respect to the ocean-continent transition in the conjugate South Newfoundland Basin, then magnetic anomalies can be modelled simply by assuming sea-floor spreading west of 11'45'W at 10 mm yr-' beginning at M11 time (133 Myr BP), and blocks of rifted continental crust to the east. The location of the proposed ocean-continent transition in the Tagus Abyssal Plain is marked by a well-defined N-S linear magnetic anomaly which is adjacent to the oldest sea-floor spreading block. East of the proposed ocean-continent transition there is an increase in the depth to basement similar to that found east of the ocean-continent transition in the Iberia Abyssal Plain and elsewhere. This model also allows us to explain why Purdy's (1975) seismic refraction line A-AR in the Tagus Abyssal Plain cannot be interpreted as a conventional reversed pair because most of Line A was shot over the ocean-continent transition zone and most of Line A R over thinned continental crust.Remarkably similar velocity/depth structures to that under Line 5 are found close to the ocean-continent transition zone off the whole of western Iberia, in areas which show no clear evidence of fracture zones. Therefore it appears more likely that the seismic structure of Line 5 is due to its proximity to the ocean-continent transition than to a local association with a fracture zone and further, that its structure is typical of this transition off the western margin of Iberia. We also suspect that the low upper mantle velocities associated with the ocean-continent transition indicate the widespread occurrence of serpentinized peridotite.

Western • is bounded by a nonvolcanic rifted continental margin made up of three apparently independent segments. The age of breakup decreases from south to north. Seismic refraction and reflection profiles, and magnetic and gravity data from each segment, show a consistent pattern of geophysical observations across the ocean-continent transition (OCT) zone, which is a few tens of kilometers wide. We emphasize here the discovery of thin (2-4 kin) oceanic crust underlain by 7.6 inn s -1 material within the OCT. The available evidence favors the suggestion that the 7.6 km s -1 layer is serpentinized peridofite and that the thin oceanic crust is primarily the result of a poor magma supply for a few million years immediately after continental brea•p. This thin crust may be the source of some ophiolites which exhibit thin crustal sections and continental margin affinities.

Background and Objective Tendon rupture can result from fluoroquinolone exposure. The objective of this study was to quantify relative and absolute risk and determine how risk is affected by timing of exposure. Methods The UK Health Improvement Network primary care database was used to perform a nested case–control study measuring the association between fluoroquinolone exposure and tendon rupture. Adults with tendon rupture were matched on age, sex, general practice and calendar time to four controls selected from a cohort prescribed systemic fluoroquinolone or co-amoxiclav antibiotics. The relative and absolute risk of tendon rupture with fluoroquinolone exposure was calculated. Results Current fluoroquinolone exposure was associated with an increased risk of any tendon rupture (adjusted incidence rate ratio [aIRR] 1.61, 95% CI 1.25–2.09) and Achilles tendon rupture (aIRR 3.14, 95% CI 2.11–4.65) that persisted for 60 days. Risk increased with cumulative exposure and was greatest when co-prescribed with oral corticosteroids (aIRR 19.36, 95% CI 7.78–48.19 for Achilles tendon rupture). The adjusted rate difference (aRD) with fluoroquinolone exposure was 2.9 and 2.1 per 10,000 patients for any and Achilles tendon rupture, respectively, and was greatest in people aged ≥ 60 years prescribed concomitant oral corticosteroid therapy (aDR 19.6 for any tendon and 6.6 Achilles tendon rupture per 10,000). No association was seen with co-amoxiclav or statin exposure, or with biceps or other tendon ruptures. Conclusions Risk of tendon rupture with fluoroquinolones depends on timing, cumulative dose and concomitant exposure to oral corticosteroids. Absolute risk significantly varied by age and concomitant corticosteroid exposure, affecting elderly patients the greatest. Electronic supplementary material The online version of this article (10.1007/s40261-018-0729-y) contains supplementary material, which is available to authorized users.

IMPORTANCE Peripheral neuropathy has been associated with systemic fluoroquinolone exposure, but risk has been poorly quantified. OBJECTIVE To calculate relative and absolute risk estimates for the association of fluoroquinolone exposure with peripheral neuropathy and to examine how risk may be affected by timing of fluoroquinolone exposure and by other risk factors. DESIGN, SETTING, AND PARTICIPANTSThis nested case-control study used anonymized data from all patients routinely registered with general practices in The Health Improvement Network database, a large primary care population database in the The cohort consisted of 1 338 900 adults issued 1 or more prescriptions of fluoroquinolone (34.3%) or amoxicillin-clavulanate (65.7%) antibiotics. Adults with incident peripheral neuropathy were matched (on age, sex, general practice, and calendar time) with up to 4 controls by using incidence density sampling selected from a cohort prescribed oral fluoroquinolone or amoxicillin-clavulanate antibiotics. Incidence rate ratios of peripheral neuropathy were calculated for fluoroquinolone and for amoxicillin-clavulanate exposure and compared with nonexposure among patients without diabetes, with sensitivity analyses testing the consistency of the results. Population mean-adjusted rate differences were then estimated, including the number needed to harm for various durations of fluoroquinolone therapy. EXPOSURES Current and cumulative exposure to oral fluoroquinolone or amoxicillinclavulanate antibiotics. MAIN OUTCOMES AND MEASURESIncident peripheral neuropathy cases recorded in electronic medical records. RESULTS In total, 5357 patients with incident peripheral neuropathy (mean [SD] age, 65.6 [14.7] years; 2809 women [52.4%]) were matched to 17 285 controls (mean [SD] age, 64.4 [15.2] years; 9485 women [54.9%]) without diabetes. Current oral fluoroquinolone exposure was associated with an increased relative incidence of peripheral neuropathy compared with nonexposure (adjusted incident rate ratio, 1.47; 95% CI, 1.13-1.92). Risk increased by approximately 3% for each additional day of current fluoroquinolone exposure and persisted for up to 180 days following exposure. No significant increased risk was observed with oral amoxicillin-clavulanate exposure. The absolute risk with current oral fluoroquinolone exposure was 2.4 (95% CI, 1.8-3.1) per 10 000 patients per year of current use. The number needed to harm for a 10-day course was 152 083 patients (95% CI, 117 742-202 778) and was greatest among men and among patients older than 60 years. CONCLUSIONS AND RELEVANCEThe results of the present study suggested that oral fluoroquinolone therapy was associated with an increased risk of incident peripheral neuropathy that may depend on the timing of the exposure and the cumulative dose. Health care professionals should consider these potential risks when prescribing fluoroquinolone antibiotics.