Evidence of Fluid Induced Earthquake Swarms From High Resolution Earthquake Relocation in the Main Ethiopian Rift

Fluid overpressure and fluid migration are known to be able to trigger or induce fault slip. However, relatively little is known about the role of fluids on generating earthquakes in some of the major continental rifts. To address this, we investigate the interaction between fluids and faults in the Main Ethiopian Rift (MER) using a large seismicity catalog that covers both the rift axis and rift margin. We performed cross-correlation analysis on four major earthquake clusters (three within the rift and one on the rift margin) in order to significantly improve accuracy of the earthquake relative relocations and to quantify families of earthquakes in which waveforms are similar. We also analyzed variation of seismicity rate and seismic moment release through time for the four clusters. The major results are that for all four clusters the earthquake relocations are 5–15 km deep, aligned to clear N-NNE striking, steeply (>60°) dipping planes. For the three clusters within the rift, the cross-correlation analysis identifies earthquake families that occur in short swarms during which seismic rate and moment release increases. Together, this space and time pattern of the seismicity strongly points toward them being fluid induced, with fluid likely sourced from depth such as mantle derived CO2. In contrast, the seismicity on the rift margin lacks earthquake families, with occurrence of earthquakes more continuous in nature, which we interpret as pointing toward tectonic stress-driven microseismic creep. Overall, our results suggest that deep sourced fluid migration within the rift is an important driver of earthquake activity

Minimally-invasive treatments for benign thyroid nodules: recommendations for information to patients and referring physicians by the Italian Minimally-Invasive Treatments of the Thyroid group

Purpose: In this paper, the members of the Italian Working Group on Minimally-Invasive Treatments of the Thyroid (MITT group) aim to summarize the most relevant information that could be of help to referring physicians and that should be provided to patients when considering the use of MITT for the treatment of benign thyroid nodules. Methods: An interdisciplinary board of physicians with specific expertise in the management of thyroid nodules was appointed by the Italian MITT Group. A systematic literature search was performed, and an evidence-based approach was used, including also the knowledge and the practical experience of the panelists to develop the paper. Results: The paper provides a list of questions that are frequently asked by patients to operators performing MITT, each with a brief and detailed answer and more relevant literature references to be consulted. Conclusions: This paper summarizes the most relevant information to be provided to patients and general practitioners/referring physicians about the use of MITT for the treatment of benign thyroid nodules

Mapping Hydrothermal Alteration at the Fentale-Dofan Magmatic Segment of the Main Ethiopian Rift

The Main Ethiopian Rift (MER) is characterized by extensional tectonics and volcanism, associated with active hydrothermal systems, hydrothermal alteration and fumarolic deposits. The spatial distribution of these hydrothermal products and their link with faults and rock types provides important clues to what controls fluid flow in the subsurface. However, little is known about this in the East African Rift. We address this issue with a multidisciplinary approach in the Fentale-Dofan magmatic segment of the MER, an area characterized by intense volcanic and tectonic activity and a geothermal prospect. Primarily we conduct mapping of hydrothermal alteration and fumarolic deposits, and rock lithologies using a surface feature classification technique of multispectral satellite images. Then we interpret the map using a new database of faults and active hydrothermal manifestations such as hot-springs and fumaroles. We find that the surface hydrothermal alteration and deposits are mainly focused near Fentale and the Dofan Volcanic Complex (DVC). At DVC the hydrothermal products are focused on rhyolites on the western side of the volcano, in an area of intense NNE striking, rift parallel faults. At Fentale volcano the hydrothermal products are mainly associated with ignimbrite and show a circular pattern around the volcanic edifice, but also in places follow the NNE striking faults. At Fentale, the more complex association of hydrothermal products and active manifestations around the edge of the ignimbrite suggests formation contacts may also localize fluid flow in places. At both volcanoes the association between hydrothermal products with either the rhyolites and ignimbrites is likely due to them being relatively easily altered (in comparison to basalt), and also their brittle nature allows for fracturing through which localized fluid flow can occur (as opposed to the sediments). The general pattern of hydrothermal products suggests a stronger structural influence at the DVC with respect to Fentale. The presence of hydrothermal products and active hydrothermal manifestations, along with other lines of evidence such as locus of subsurface dike intrusion at the volcanic centres, suggest that discrete and localized magma reservoirs beneath Fentale and the DVC are the heat source for hydrothermal circulation. Our study also demonstrates that geology, including hydrothermal deposits, can be successfully mapped using automated remote sensing based classification

Capillaroscopic evidence of microvascular damage in volleyball players

Volleyball players experience repetitive stress that involves their hands and, in particular, their fingers. Literature reports that repetitive trauma can lead to local vascular abnormalities, such as reduced capillarization and lower resting blood flow. These anomalies could be related to the presence of dysfunctional endothelium. The aim of this study is to correlate the capillaroscopic findings by nailfold video capillaroscopy (NVC) to volleyball practice in order to early detect possible anomalies and perform an adequate follow-up to avoid damages that could negatively affect sport practice and the players’ health status. In this study, 38 subjects were enrolled, 19 volleyball players and 19 healthy non-players as a comparison group. In almost all the players, we found capillaroscopic alterations of the “aspecific pattern” type without substantial gender differences. We may assume that the repeated traumas involving players’ fingers can negatively modify their microcirculation. Based on these observations, it could be a desirable clinical practice to screen professional volleyball players with NVC in order to implement preventive strategies aimed at protecting the health of athletes

Indeterminate tcdB using a Clostridium difficile PCR assay: a retrospective cohort study

Abstract Background C. difficile (CD) real-time polymerase chain reaction (PCR) for toxin B gene (tcdB) is more sensitive, and reduces turnaround time when compared to toxin immunoassay. We noted typical amplification curves with high tcdB cycle thresholds (Ct) and low endpoints (Ept) that are labeled negative by the Xpert® C. difficile assay (Cepheid) and undertook this study to determine their significance. Methods We defined an indeterminate CD assay result as detection of a typical PCR amplification curve with an Ept >10 that was interpreted as negative by the Xpert® assay. Samples with indeterminate Xpert® result were collected for 5 months and retested by Xpert®, cultured for toxigenic CD, and isolates subjected to PCR ribotyping, detection of toxin genes and multilocus variable-number tandem repeat analysis (MLVA) typing. Chart reviews were completed to assess if patients met the Society of Healthcare Epidemiology of America and the Infectious Diseases Society of America CD infection (CDI) clinical case definition. Illness severity was compared with tcdB Ct and culture results. Results During the 5-month study period, 48/3620 (1%) of specimens were indeterminate and 387/3620 (11%) were positive. Of the 48 patients with indeterminate results, 39 (81%) met the clinical case definition of CDI, and 7 of these (18%) met criteria for severe CDI. Toxigenic stool cultures were positive for 86% (6/7) of patients with severe CDI, 19% (6/32) of patients with non-severe CDI, and 44% (4/9) of patients who did not meet the clinical case definition of CDI (p = 0.002). Lower tcdB Ct and higher Ept were associated with greater likelihood of toxigenic culture positivity (p = 0.03) and more severe symptoms (p = 0.06). Indeterminate results were not associated with a particular technologist or instrument module, or CD strain type. Conclusions A subset of specimens (1%) using the Xpert® C. difficile assay have typical amplification curves and are interpreted as negative. At least one-third of these results are associated with positive CD culture. The mechanism of these indeterminate results is not technique-related, equipment-related, or due to particular CD strains. Clinicians should be aware that even PCR testing has the potential to miss CDI cases and further highlights the importance of clinical context when interpreting results

Five-year results of radiofrequency and laser ablation of benign thyroid nodules: a multicenter study from the Italian minimally-invasive treatments of the thyroid group

Background: Radiofrequency and laser ablation (RFA and LA) are effective treatments for benign thyroid nodules. Due to their relatively recent introduction into clinical practice, there are limited long-term follow-up studies. This study aimed to evaluate technique efficacy, rate of regrowth and retreatment over 5 years following RFA or LA and to identify predictive factors of outcome. Methods: In this multicenter retrospective study, the rate of technique efficacy, regrowth, and retreatment were evaluated in 406 patients treated with either RFA or LA and followed for 5 years after initial treatment. Propensity score matching was used to compare treatments. Cumulative incidence studies with hazard models were used to describe regrowth and retreatment trends and to identify prognostic factors. Logistic regression models and receiver operating characteristics analyses were used for risk factors and their cut-offs. Results: RFA and LA significantly reduced benign thyroid nodule volume, and this reduction was generally maintained for 5 years. Technique efficacy (defined as a reduction 65 50% after 1 year from the treatment) was achieved in 74% of patients (85% in the RFA and 63% in the LA group). Regrowth occurred in 28% of patients (20% in the RFA and 38% in the LA group). In the majority of cases, further treatment was not required as only 18% of patients were retreated (12% in the RFA and 24% in the LA group). These data were confirmed by propensity score matching. Cumulative incidence studies showed that RFA was associated with a lower risk of regrowth and a lower risk of requiring retreatment over time. Overall, technique inefficacy and regrowth were associated with low energy delivery. Retreatments were more frequent in young patients, in large nodules, in patients with lower volume reduction at 1-year, and in cases of low energy delivery (optimal cut-off was 918 J/mL for RFA). Conclusions: Both thermal ablation techniques result in a clinically significant and long-lasting volume reduction of benign thyroid nodules. The risk of regrowth and needing retreatment was lower after RFA. The need for retreatment was associated with young age, large baseline volume, and treatment with low energy delivery