Imaging the Galápagos mantle plume with an unconventional application of floating seismometers.

We launched an array of nine freely floating submarine seismometers near the Galápagos islands, which remained operational for about two years. P and PKP waves from regional and teleseismic earthquakes were observed for a range of magnitudes. The signal-to-noise ratio is strongly influenced by the weather conditions and this determines the lowest magnitudes that can be observed. Waves from deep earthquakes are easier to pick, but the S/N ratio can be enhanced through filtering and the data cover earthquakes from all depths. We measured 580 arrival times for different raypaths. We show that even such a limited number of data gives a significant increase in resolution for the oceanic upper mantle. This is the first time an array of floating seismometers is used in seismic tomography to improve the resolution significantly where otherwise no seismic information is available. We show that the Galápagos Archipelago is underlain by a deep (about 1900 km) 200-300 km wide plume of high temperature, with a heat flux very much larger than predicted from its swell bathymetry. The decrease of the plume temperature anomaly towards the surface indicates that the Earth's mantle has a subadiabatic temperature gradient.

Areas prone to slow slip events impede earthquake rupture propagation and promote afterslip.

At subduction zones, transient aseismic slip occurs either as afterslip following a large earthquake or as episodic slow slip events during the interseismic period. Afterslip and slow slip events are usually considered as distinct processes occurring on separate fault areas governed by different frictional properties. Continuous GPS (Global Positioning System) measurements following the 2016 Mw (moment magnitude) 7.8 Ecuador earthquake reveal that large and rapid afterslip developed at discrete areas of the megathrust that had previously hosted slow slip events. Regardless of whether they were locked or not before the earthquake, these areas appear to persistently release stress by aseismic slip throughout the earthquake cycle and outline the seismic rupture, an observation potentially leading to a better anticipation of future large earthquakes.

Factors associated with regional rheumatic pain disorders in a population of Puerto Ricans with diabetes mellitus.

The aim of the study was to determine the prevalence and factors associated with bursitis/tendonitis disorders in Puerto Ricans with diabetes mellitus (DM). A cross-sectional study was performed in 202 adult Puerto Ricans (100 DM patients and 102 non-diabetic subjects). For each participant, a complete medical history and a musculoskeletal exam were systematically performed. Socio-demographic parameters, health-related behaviors, comorbidities, and pharmacotherapy were determined for all subjects. For DM patients, disease duration, glycemic control, and DM long-term complications were also examined. Multivariate logistic regression analyses were used to determine the factors associated with bursitis/tendonitis disorders. The mean (SD) age for DM patients and non-diabetic controls were 53.3 (12.9) and 50.0 (13.1) years; 64.0 and 64.7 % of DM patients and controls were females, respectively. Overall, the prevalence of bursitis/tendonitis was higher in DM patients than among non-diabetics (59.0 % vs. 29.4 %, p < 0.01). In multivariate analyses, DM patients had 2.47 (95 % CI 1.05, 5.84) the odds of having bursitis/tendonitis as compared to non-diabetics. Specifically, DM patients had a higher frequency of flexor tenosynovitis, De Quervain's tenosynovitis, lateral epicondylitis, medial epicondylitis, trochanteric bursitis, and anserine bursitis than non-diabetic subjects (p < 0.05). Among DM patients, multivariate analyses showed that those with bursitis/tendonitis were more likely to be female [OR (95 % CI) 4.55 (1.42, 14.55)] and have peripheral vascular disease [OR (95 % CI) 8.48 (1.71, 41.93)]. In conclusion, bursitis/tendonitis disorders were common in this population of Hispanics with DM. Among DM patients, bursitis/tendonitis disorders were more frequent in women and those with long-term complications such as peripheral vascular disease.

Inflammatory myopathy as the initial presentation of cryoglobulinaemic vasculitis.

Cryoglobulinaemic vasculitis is characterised by immunoglobulin deposition at low temperatures. The most common manifestations are cutaneous involvement, arthralgias, Raynaud's phenomenon, peripheral neuropathy and renal disease. Myopathy is unusual and only a few cases have been reported. Here, we present a 31-year-old woman who developed progressive muscle weakness involving upper and lower extremities, dysphagia, paraesthesias and palpable purpura. Diagnostic studies revealed elevated creatine kinase, diffuse myopathic and sensorimotor axonal neuropathy on electromyography and nerve conduction studies, and inflammatory myopathy on muscle biospsy. Cryoglobulin levels were elevated on two occasions. She responded favourably to cyclophosphamide and high-dose corticosteroids. Cyclophosphamide was continued for 1 year followed by methotrexate. Prednisone was gradually tapered and discontinued 1 year later. She remained in clinical remission after 4 years of follow-up. This case suggests that cryoglobulinaemia should be considered in the differential diagnosis of a patient presenting with inflammatory myopathy.

Association of hand or knee osteoarthritis with diabetes mellitus in a population of Hispanics from Puerto Rico.

BACKGROUND: Although a higher prevalence of osteoarthritis (OA) has been reported among diabetes mellitus (DM) patients, inconsistencies and limitations of observational studies have precluded a conclusive association. OBJECTIVE: The objective of this study was to evaluate the association of hand or knee OA with DM in a population of Hispanics from Puerto Rico. METHODS: A cross-sectional study was performed in 202 subjects (100 adult DM patients as per the National Diabetes Data Group Classification and 102 nondiabetic subjects). Osteoarthritis of hand and knee was ascertained using the American College of Rheumatology classification criteria. Sociodemographic characteristics, health-related behaviors, comorbidities, pharmacotherapy, and DM clinical manifestations were determined. Multivariable logistic regression was used to evaluate the association of DM with hand or knee OA and to evaluate factors associated with hand or knee OA among DM patients. RESULTS: The mean (SD) age for DM patients was 51.6 (13.1) years; 64.0% were females. The mean (SD) DM duration was 11.0 (10.4) years. The prevalence of OA in patients with DM and nondiabetic subjects was 49.0% and 26.5%, respectively (P < 0.01). In the multivariable analysis, patients with DM had 2.18 the odds of having OA when compared with nondiabetic subjects (95% confidence interval [CI], 1.12-4.24). In a subanalysis among DM patients, female patients were more likely to have hand or knee OA (odds ratio [95% CI], 5.06 [1.66-15.66]), whereas patients who did not use insulin alone for DM therapy were more likely to have OA (odds ratio [95% CI], 4.44 [1.22-16.12]). CONCLUSIONS: In this population of Hispanics from Puerto Rico, DM patients were more likely to have OA of hands or knees than were nondiabetic subjects. This association was retained in multivariable models accounting for established risk factors for OA. Among DM patients, females were at greater risk for OA, whereas the use of insulin was negatively associated.