Monitoring Seismic Velocity Changes Across the San Jacinto Fault Using Train-Generated Seismic Tremors

Microseismic noise has been used for seismic velocity monitoring. However, such signals are dominated by low-frequency surface waves that are not ideal for detecting changes associated with small tectonic processes. Here we show that it is possible to extract stable, high-frequency body waves using seismic tremors generated by freight trains. Such body waves allow us to focus on small velocity perturbations in the crust with high spatial resolution. We report on 10 years of seismic velocity temporal changes at the San Jacinto Fault. We observe and map a two-month-long episode of velocity changes with complex spatial distribution and interpret the velocity perturbation as produced by a previously undocumented slow-slip event. We verify the hypothesis through numerical simulations and locate this event along a fault segment believed to be locked. Such a slow-slip event stresses its surroundings and may trigger a major earthquake on a fault section approaching failure.

Review article: cytomegalovirus and inflammatory bowel disease

BACKGROUND

The association between ulcerative colitis and cytomegalovirus (CMV) has been recognised for over 50 years; and the role of CMV in ulcerative colitis in general, and steroid resistance in particular, remains a topic of ongoing controversy. The outcome for patients with CMV reactivation appears worse than that for patients without reactivation, but it is not entirely clear whether CMV is a contributor or a bystander and if treatment with anti-virals alters the course of inflammatory bowel disease (IBD).

AIM

To review the role of CMV associated with IBD, including epidemiology, clinical features, diagnosis and management strategies.

METHODS

By reviewing literature available on CMV associated with IBD in adult patients. A PubMed literature search was performed using the following terms individually or in combination: CMV colitis, cytomegalovirus colitis, IBD and CMV, CMV treatment.

RESULTS

Cytomegalovirus reactivation is common in patients with severe colitis, with a reported prevalence of 4.5-16.6%, and as high as 25% in patients requiring colectomy for severe colitis. The outcome for this group of patients appears worse than that for patients without reactivation; however, reported remission rates following treatment with anti-viral therapy are as high as 71-86%.

CONCLUSIONS

Evidence, although not conclusive, supports testing for CMV colonic disease in cases of moderate to severe colitis, by processing biopsies for haematoxylin and eosin staining with immunohistochemistry and/or, CMV DNA real-time polymerase chain reaction; and if present treating with ganciclovir.

Recurrence of pulmonary mucinous cystic tumor of borderline malignancy

Cystic mucinous tumors of the lung are recently described neoplasms whose histology is different from most lung adenocarcinomas, and represent a spectrum of malignant potential. Little is known of the behavior of the more malignant subtype. We present a cystic mucinous tumor of borderline malignancy that recurred locally following initial limited resection, and was treated with lobectomy.

Senior Fitness-For the Health of It

Exercise won't reverse the aging process, but older adults who exercise regularly can improve cardiovascular endurance, physical work capacity, and bone mineral content and lead more vital lives.