Induced seismicity response of hydraulic fracturing: results of a multidisciplinary monitoring at the Wysin site, Poland

Shale oil and gas exploitation by hydraulic fracturing experienced a strong development worldwide over the last years, accompanied by a substantial increase of related induced seismicity, either consequence of fracturing or wastewater injection. In Europe, unconventional hydrocarbon resources remain underdeveloped and their exploitation controversial. In UK, fracturing operations were stopped after the M_w 2.3 Blackpool induced earthquake; in Poland, operations were halted in 2017 due to adverse oil market conditions. One of the last operated well at Wysin, Poland, was monitored independently in the framework of the EU project SHEER, through a multidisciplinary system including seismic, water and air quality monitoring. The hybrid seismic network combines surface mini-arrays, broadband and shallow borehole sensors. This paper summarizes the outcomes of the seismological analysis of these data. Shallow artificial seismic noise sources were detected and located at the wellhead active during the fracturing stages. Local microseismicity was also detected, located and characterised, culminating in two events of M_w 1.0 and 0.5, occurring days after the stimulation in the vicinity of the operational well, but at very shallow depths. A sharp methane peak was detected ~19 hours after the M_w 0.5 event. No correlation was observed between injected volumes, seismicity and groundwater parameters.

The November 2017 Mw 5.5 Pohang earthquake: A possible case of induced seismicity in South Korea

The moment magnitude (M_w) 5.5 earthquake that struck South Korea in November 2017 was one of the largest and most damaging events in that country over the past century. Its proximity to an enhanced geothermal system site, where high-pressure hydraulic injection had been performed during the previous 2 years, raises the possibility that this earthquake was anthropogenic. We have combined seismological and geodetic analyses to characterize the mainshock and its largest aftershocks, constrain the geometry of this seismic sequence, and shed light on its causal factors. According to our analysis, it seems plausible that the occurrence of this earthquake was influenced by the aforementioned industrial activities. Finally, we found that the earthquake transferred static stress to larger nearby faults, potentially increasing the seismic hazard in the area.

[Hemoptysis as the first sign of ruptured thoracic aorta]

Acute aortic rupture is associated with a high mortality. The leading symptoms are chest pain, dyspnea and hemodynamic instability as well as hemoptysis. In the current case report a patient with known coronary artery disease and prior coronary artery bypass surgery presented with hemoptysis. He was initially treated for a presumed gastroenterological disorder. The chest X-ray delineated a structure suggestive of aortic rupture and this diagnosis was confirmed by computed tomography. Emergency treatment was performed by implantation of an endovascular stent prosthesis. This procedure is currently regarded the standard treatment of rupture of the descending thoracic aorta. We conclude our case report with a discussion of epidemiology, symptoms, pathogenesis and therapy of this clinically dramatic disease.

Strong surface contribution to the nonlinear Meissner effect in d-wave superconductors

We demonstrate that in a d-wave superconductor the bulk nonlinear Meissner effect is dominated by a surface effect due to Andreev bound states at low temperatures. The contribution of this surface effect to the nonlinear response coefficient follows a 1/T3 law with the opposite sign compared to the bulk 1/T behavior. The crossover from bulk dominated behavior to surface dominated behavior occurs at a temperature of T/Tc∼1/square root(κ). We present an approximate analytical calculation, which supports our numerical calculations and provides a qualitative understanding of the effect. The effect can be probed by intermodulation distortion experiments.

Effect of surface Andreev bound states on the Bean-Livingston barrier in d-wave superconductors

We study the influence of surface Andreev bound states in d-wave superconductors on the Bean-Livingston surface barrier for entry of a vortex line into a strongly type-II superconductor. Starting from Eilenberger theory, we derive a generalization of London theory to incorporate the anomalous surface currents arising from the Andreev bound states. This allows us to find an analytical expression for the modification of the Bean-Livingston barrier in terms of a single parameter describing the influence of the Andreev bound states. We find that the field of first vortex entry is significantly enhanced. Also, the depinning field for vortices near the surface is renormalized. Both effects are temperature dependent and depend on the orientation of the surface relative to the d-wave gap.

Shadow on the wall cast by an Abrikosov vortex

At the surface of a d-wave superconductor, a zero-energy peak in the quasiparticle spectrum can be observed. This peak appears due to Andreev bound states and is maximal if the nodal direction of the d-wave pairing potential is perpendicular to the boundary. We examine the effect of a single Abrikosov vortex in front of a reflecting boundary on the zero-energy density of states. We can clearly see a splitting of the low-energy peak and therefore a suppression of the zero-energy density of states in a shadowlike region extending from the vortex to the boundary. This effect is stable for different models of the single Abrikosov vortex, for different mean free paths and also for different distances between the vortex center and the boundary. This observation promises to have also a substantial influence on the differential conductance and the tunneling characteristics for low excitation energies.

[Entrapment-syndrome of the popliteal artery: morphological and functional diagnosis using MRT inclusive provocation test]

A 30-year old man with pain in the right calf was submitted. Typical cardiovascular risk factors were excluded. Contrast enhanced MR-angiography at rest showed occlusion of right popliteal artery with collateral vessels due to an abnormal origin of medial head of gastrocnemius muscle at femoral diaphysis. In contrast to a normal MR-angiography at rest the exercise test detected a lateral deviation and a severe functional stenosis of the left popliteal artery. This was caused by an abnormal medial origin of medial head of gastrocnemius muscle at the inner femoral condylus. The patient has been treated with vascular reconstruction combined with myectomy on the right side and with myectomy only on the left side. These findings showed two different types of popliteal artery entrapment syndrome in one patient. MRI is able to detect the different types especially in different stages. Irreversible damages of popliteal artery in early diagnosed stages may thereby be prevented.

Anomalous coherence peak in the microwave conductivity of c-axis oriented MgB2 thin films

The temperature dependence of the real part of the microwave complex conductivity at 17.9 GHz obtained from surface impedance measurements of two c-axis oriented MgB2 thin films reveals a pronounced maximum at a temperature around 0.6 times the critical temperature. Calculations in the frame of a two-band model based on Bardeen-Cooper-Schrieffer (BCS) theory suggest that this maximum corresponds to an anomalous coherence peak resembling the two-gap nature of MgB2. Our model assumes there is no interband impurity scattering and a weak interband pairing interaction, as suggested by band structure calculations. In addition, the observation of a coherence peak indicates that the pi band is in the dirty limit and dominates the total conductivity of our films.

Fermi surface topology and the upper critical field in two-band superconductors: application to MgB2

Recent measurements of the anisotropy of the upper critical field B(c2) on MgB2 single crystals have shown a puzzling strong temperature dependence. Here, we present a calculation of the upper critical field based on a detailed modeling of band structure calculations that takes into account both the unusual Fermi surface topology and the two gap nature of the superconducting order parameter. Our results show that the strong temperature dependence of the B(c2) anisotropy can be understood as an interplay of the dominating gap on the sigma band, which possesses a small c-axis component of the Fermi velocity, with the induced superconductivity on the pi-band possessing a large c-axis component of the Fermi velocity. We provide analytic formulas for the anisotropy ratio at T=0 and T=T(c) and quantitatively predict the distortion of the vortex lattice based on our calculations.

Quantitative ER <--> Golgi transport kinetics and protein separation upon Golgi exit revealed by vesicular integral membrane protein 36 dynamics in live cells

To quantitatively investigate the trafficking of the transmembrane lectin VIP36 and its relation to cargo-containing transport carriers (TCs), we analyzed a C-terminal fluorescent-protein (FP) fusion, VIP36-SP-FP. When expressed at moderate levels, VIP36-SP-FP localized to the endoplasmic reticulum, Golgi apparatus, and intermediate transport structures, and colocalized with epitope-tagged VIP36. Temperature shift and pharmacological experiments indicated VIP36-SP-FP recycled in the early secretory pathway, exhibiting trafficking representative of a class of transmembrane cargo receptors, including the closely related lectin ERGIC53. VIP36-SP-FP trafficking structures comprised tubules and globular elements, which translocated in a saltatory manner. Simultaneous visualization of anterograde secretory cargo and VIP36-SP-FP indicated that the globular structures were pre-Golgi carriers, and that VIP36-SP-FP segregated from cargo within the Golgi and was not included in post-Golgi TCs. Organelle-specific bleach experiments directly measured the exchange of VIP36-SP-FP between the Golgi and endoplasmic reticulum (ER). Fitting a two-compartment model to the recovery data predicted first order rate constants of 1.22 +/- 0.44%/min for ER --> Golgi, and 7.68 +/- 1.94%/min for Golgi --> ER transport, revealing a half-time of 113 +/- 70 min for leaving the ER and 1.67 +/- 0.45 min for leaving the Golgi, and accounting for the measured steady-state distribution of VIP36-SP-FP (13% Golgi/87% ER). Perturbing transport with AlF(4)(-) treatment altered VIP36-SP-GFP distribution and changed the rate constants. The parameters of the model suggest that relatively small differences in the first order rate constants, perhaps manifested in subtle differences in the tendency to enter distinct TCs, result in large differences in the steady-state localization of secretory components.

[Simultaneous or stepwise procedure in combined minimal invasive and conventional operation methods in vascular surgery]

Long-term results of femoral angioplasty and stenting are not as successful as open surgical procedures. Transfemoral retrograde recanalisation of the iliac vessel by semiclosed endarterectomy is a low-invasive procedure. Certainly the outcome is characterised by a number of early occlusions caused by dissections or remaining intimal flaps. Recent advances in endovascular management of occlusive disease have changed the situation. Intraoperative control of lumen by angioscopy and removal of occlusive material via TV-monitored endoscopic manipulation has induced better results of endarterectomy. In addition to this more effective recanalisation, the proximal intimal step, mostly at the level of the iliac bifurcation, is managed by intraoperative balloon dilatation and stenting. This combined approach has reduced the necessity of reoperation by about 15%. The cumulative 5-year patency rate for this combined procedure is 88%.

Epidemiology of respiratory syncytial virus infection requiring hospitalization in East Denmark

BACKGROUND

Prophylaxis against infection caused by respiratory syncytial virus (RSV) with high titered RSV immunoglobulin or humanized antibody may soon be available in Europe.

OBJECTIVE

To study the epidemiology of RSV infections requiring hospitalization in infants <6 months in East Denmark to provide a rational basis for decisions concerning prophylaxis against RSV.

METHOD

Populat ion-based retrospective review of case records of infants <6 months admitted to pediatric departments with RSV infection in East Denmark from November 1, 1995, to April 30, 1996.

RESULTS

Data were obtained from 459 infants. Seventy-three had predisposing conditions: prematurity, 49; pulmonary disease, 2; congenital heart disease, 7; neurologic disease, 6; others, 9. One preterm infant had bronchopulmonary dysplasia. The incidence of RSV infection requiring hospitalization in East Denmark among infants <6 months was estimated to be 34/1000/season. It was 32/1000/season among term infants and 66/ 1000/season among preterm infants (P<0.001). Infants with predisposing conditions and/or nosocomial infection (n = 24) had significantly more severe courses than otherwise healthy infants (P<0.01). One-hundred thirty infants received respiratory support by nasal continuous positive airway pressure, but only six required mechanical ventilation. No infants died.

CONCLUSION

The course of RSV disease in East Denmark was milder than reported elsewhere, possibly as a result of the low prevalence of bronchopulmonary dysplasia in Denmark. However, RSV constitutes a considerable burden to the Danish pediatric health care system, and therefore prophylaxis against RSV is desirable.