Measuring displacements of strike-slip paleoearthquakes from trenching excavations requires detailed 3D trenching excavations. Here a new methodology utilizing an iOS based laser scanner and ...structure-from-motion is used to reconstruct stratigraphy and trace a displaced fluvial channel sequence across the Dog Valley fault in Northeastern California. The Dog Valley fault is a left-lateral strike slip fault in the northern Walker Lane. The northern Walker Lane accommodates ~5-7 mm/yr of dextral shear; however, the relative rates of deformation and earthquake history of the fault have not been previously assessed. Here, we present geomorphic mapping observations and preliminary paleoseismic trenching results from the Dog Valley fault. Lidar data reveal a clear east-northeast striking fault trace that extends about ~25 km from the Prosser Creek drainage west of the Polaris Fault near Highway 89 to the northwest flank of Peavine Mountain. The main trace of the fault appears to project through Stampede dam. Youthful fault scarps are visible along much of the fault, with alternating northwest- and southeast-facing scarps. Clear lateral displacements are largely absent along the fault, however right-stepping fault strands, sidehill benches, linear valleys and ridges, and alternating scarp facing directions are all consistent with left-lateral strike slip displacement. Stratigraphic and structural relations exposed in the Dog Valley fault trench show clear truncations and tilting of bedded fluvial and peat deposits and provide evidence for the occurrence of two Holocene earthquakes: the most recent earthquake postdates ~8 ka, and an earlier earthquake is inferred to have occurred between 8491-8345 cal. ybp. Based on 3D excavations of a prominent channel margin, the most recent earthquake was associated with ~ 115 cm of left-lateral displacement, corresponding to an M6.7 earthquake.
National and subspecialty guidelines for lung and esophageal cancers recommend treatment decisions to be made in a multidisciplinary tumor board (MTB). This study prospectively analyzes the actual ...impact of presentation at the thoracic tumor board on decision making in thoracic cancer cases.
During the electronic submission process for presentation at MTB managing physicians documented their current treatment plan. The initial treatment plan was compared with the MTB final recommendation. Patient demographics, physician's proposed treatment plan, MTB recommendation, and documentation of application of MTB recommendations were prospectively recorded in an Institutional Review Board approved database.
Between June 2010 and December 2012, 185 patients with esophageal and 294 patients with lung cancer were presented at the MTB. One hundred sixty-six patients were presented on more than 1 occasion, resulting in 724 assessments of 479 patients. In 48 esophageal cancer patients (26%) and 118 lung cancer patients (40%) MTB recommendations differed from the initial treatment plan. Overall, a differing MTB recommendation from the primary treatment plan occurred in 330 of 724 case presentations (46%). The MTB recommendations changed treatment plans in 40% and staging and assessment plans in 60% of patients. Follow-up in a cohort of 249 patients confirmed that MTB recommendations were followed in 97% of cases.
This study validates the impact of the thoracic MTB. Recommendations will differ from the managing providers' initial plan in 26% to 40% of cases. However, MTB recommendations can be successfully initiated in the majority of patients. Complex thoracic cancer patients will benefit from multidisciplinary review and should ideally be presented at tumor board.
Current models used to assess earthquake and tsunami hazards are inadequate where creep dominates a subduction megathrust. Here we report geological evidence for large tsunamis, occurring on average ...every 300–340 years, near the source areas of the 1946 and 1957 Aleutian tsunamis. These areas bookend a postulated seismic gap over 200 km long where modern geodetic measurements indicate that the megathrust is currently creeping. At Sedanka Island, evidence for large tsunamis includes six sand sheets that blanket a lowland facing the Pacific Ocean, rise to 15 m above mean sea level, contain marine diatoms, cap terraces, adjoin evidence for scour, and date from the past 1700 years. The youngest sheet and modern drift logs found as far as 800 m inland and >18 m elevation likely record the 1957 tsunami. Previously unrecognized tsunami sources coexist with a presently creeping megathrust along this part of the Aleutian Subduction Zone.
Key Points
First geological evidence for prehistoric tsunamis in the Aleutian Arc
Large tsunamis have occurred every 300–340 yrs, on average, offshore Unalaska Island
Previously unrecognized tsunami sources exist along a creeping part of the Aleutian megathrust
Throughout the COVID-19 pandemic, hundreds of millions of people worldwide have become new users of respiratory protective devices. Facemasks and KN95 respirators utilizing an ear loop straps system ...(ELSS) have recently become popular among occupational and non-occupational populations. Part of this popularity is due to the ease of wearability as compared with traditional devices utilizing two headbands, one worn over the head and the other behind the neck-a universal strap system used in NIOSH-certified N95 filtering facepiece respirators (FFRs). Some users convert the two-strap configuration to an adjustable ELSS. The first objective of this pilot study was to quantitatively characterize how such a conversion impacts the respirator fit. Additionally, a novel faceseal (NFS) technology, which has been previously demonstrated to enhance the fit of N95 FFRs, was deployed to modify the ELSS-converted N95 FFRs. The second objective of this study was to quantify the fit improvement that results from adding the NFS to the ELSS. The study was conducted by performing the Occupational Safety and Health Administration (OSHA)-approved quantitative fit testing (QNFT) on 16 human subjects featuring different facial shapes and dimensions. Three models of cup-shaped N95 FFRs were tested in three versions: the standard version with manufacturer's strap system, the ELSS-converted, and the ELSS-converted version modified by adding the NFS. QNFT demonstrated that the fit of an N95 FFR featuring the traditional/standard headbands strap system is negatively impacted when this system is converted to an ELSS. The fit of an ELSS-converted respirator can be significantly improved by the addition of the NFS. We found that the FFR model and the strap system version are significant factors affecting the QNFT-determined respirator fit factor (FF), as well as the OSHA QNFT pass rate (FF ≥100). The findings suggest that the current NFS, if further improved, has a potential for developing a 'universally fitting' ELSS-equipped N95 FFR that can be used by the general public, the vast majority of whom do not have access to OSHA fit requirements.
Can a predominantly creeping segment of a subduction zone generate a great (M > 8) earthquake? Despite Russian accounts of strong shaking and high tsunamis in 1788, geodetic observations above the ...Aleutian megathrust indicate creeping subduction across the Shumagin Islands segment, a well‐known seismic gap. Seeking evidence for prehistoric great earthquakes, we investigated Simeonof Island, the archipelago's easternmost island, and found no evidence for uplifted marine terraces or subsided shorelines. Instead, we found freshwater peat blanketing lowlands, and organic‐rich silt and tephra draping higher glacially smoothed bedrock. Basal peat ages place glacier retreat prior to 10.4 ka and imply slowly rising (<0.2 m/ka) relative sea level since ~3.4 ka. Storms rather than tsunamis probably deposited thin, discontinuous deposits in coastal sites. If rupture of the megathrust beneath Simeonof Island produced great earthquakes in the late Holocene, then coseismic uplift or subsidence was too small (≤0.3 m) to perturb the onshore geologic record.
Key Points
Simeonof Island lacks evidence for great earthquakes and tsunamis
Slow sea-level rise since ~3.4 ka was unperturbed by sudden tectonic jerks
Creeping subduction in the Shumagin gap probably persisted in the late Holocene
This research quantifies streamflow temporal configuration and demonstrates the advantages of examining the hydrologic record on a day‐to‐day basis, heretofore unavailable with statistical‐based ...index parameters. The streamflow chronological structure represents a previously untapped wealth of information that would benefit ecohydrology allowing alternate lines of investigation, re‐evaluating past research in a new light and expanding analysis options for ecohydrologists. Innovative approaches are introduced to quantify this important but overlooked hydrologic property. To accomplish this, a non‐index calculus‐based differential approach has been developed using the lag(1) temporal autocorrelation signature of streamflow. The techniques for quantifying discharge (Q), day‐to‐day discharge change (dQ/dt), rate of day‐to‐day discharge change (d2Q/dt2) and sequential discharge summations are explained and presented using updated data visualization methods. A dam release river impact case study for the Colorado River at Lees Ferry, Arizona, demonstrates this novel way of analyzing and comparing discharge datasets. A set of highly customizable tools for this new approach can be used as a stand‐alone analysis or to complement other existing techniques. The result is a better understanding of the hydrologic regime, permitting more focused research and more effective management planning.
Reactive oxygen species (ROS) are involved in many physiological and pathophysiological cellular processes. We used lymphocytes, which are exposed to highly oxidizing environments during ...inflammation, to study the influence of ROS on cellular function. Calcium ion (Ca(2+)) influx through Ca(2+) release-activated Ca(2+) (CRAC) channels composed of proteins of the ORAI family is essential for the activation, proliferation, and differentiation of T lymphocytes, but whether and how ROS affect ORAI channel function have been unclear. Here, we combined Ca(2+) imaging, patch-clamp recordings, and measurements of cell proliferation and cytokine secretion to determine the effects of hydrogen peroxide (H(2)O(2)) on ORAI channel activity and human T helper lymphocyte (T(H) cell) function. ORAI1, but not ORAI3, channels were inhibited by oxidation by H(2)O(2). The differential redox sensitivity of ORAI1 and ORAI3 channels depended mainly on an extracellularly located reactive cysteine, which is absent in ORAI3. T(H) cells became progressively less redox-sensitive after differentiation into effector cells, a shift that would allow them to proliferate, differentiate, and secrete cytokines in oxidizing environments. The decreased redox sensitivity of effector T(H) cells correlated with increased expression of Orai3 and increased abundance of several cytosolic antioxidants. Knockdown of ORAI3 with small-interfering RNA rendered effector T(H) cells more redox-sensitive. The differential expression of Orai isoforms between naïve and effector T(H) cells may tune cellular responses under oxidative stress.
We propose that the symptoms associated with paraesophageal hernia (PEH) are more diverse than previously suggested, and symptoms and clinical manifestations correlate to the anatomy of the hernia.
...Patients undergoing surgery for PEH were reviewed from a prospective, institutional review board-approved, single-center database. Presenting symptoms, anatomy of the PEH, demographics, and outcomes were analyzed from 2000 to 2010. Presenting symptoms were assessed for incidence and improvement after surgery. Size and configuration of the PEH were assessed with respect to presenting symptoms.
The study included 270 consecutive patients, 63% were female, and the median age was 70 years (range, 39 to 94 years). The most common presenting symptoms were heartburn in 175 patients (65%), early satiety in 136 patients (50%), chest pain in 130 patients (48%), dyspnea in 130 patients (48%), dysphagia in 129 patients (48%), regurgitation in 128 patients (47%), and anemia in 112 patients (41%). Two hundred sixty-nine patients (99.6%) had at least one symptom; the median number of symptoms was 4 (range, 0 to 10). The type of PEH was II (n=10), III (n=206), and IV (n=54), and the percent intrathoracic stomach was less than 50% (n=33), 50% to 74% (n=86), 75% to 99% (n=55), and 100% (n=96). Paraesophageal hernia type was significantly associated with heartburn (type II/III; p=0.005) and dyspnea (type IV; p=0.007). Significant associations included lower percent intrathoracic stomach with regurgitation (p=0.04); higher percent intrathoracic stomach with early satiety (p=0.02), decreased meal size (p=0.007), and dyspnea (p<0.001); and 50% to 74% intrathoracic stomach with anemia (p=0.001). With a median postoperative follow-up of 103 days, symptoms were subjectively better in patients with dyspnea (67%), early satiety (79%), regurgitation (92%), dysphagia (81%), chest pain (76%), and heartburn (93%).
Paraesophageal hernia is associated with a greater diversity of symptomatic presentation than previously thought. Asymptomatic patients are rare, and size and configuration of the hernia are associated with specific symptoms. Patients with large PEHs should be assessed by an experienced surgeon for elective repair.
Objective Assessment of the clinical impact of giant paraesophageal hernias have historically focused on upper gastrointestinal symptoms. This study assesses the effect of paraesophageal hernia ...repair on respiratory function. Methods All patients undergoing repair of giant paraesophageal hernia were prospectively entered into a database approved by the institutional review board. Patients had symptoms documented preoperatively, including dyspnea. Pulmonary function tests (PFTs) were done preoperatively and repeated a median of 106 days after repair (range, 16-660 days). Results Preoperative and postoperative PFTs were obtained in 120 unselected patients treated for paraesophageal hernia between 2000 and 2010. Patients’ median age was 74 years (range, 45-91 years), 74 (62%) were female, and median body mass index was 28.0 (range, 16.8-46.6). Median length of stay was 4 days (range, 3-10 days), and perioperative mortality was zero. Hernias were classified as type II in 3 (3%) patients, III in 92 (77%), and IV in 25 (21%). Percent of intrathoracic stomach was assigned from preoperative contrast studies and grouped as less than 50% (n = 6; 5%), 50% to 74% (n = 35; 29%), 75% to 99% (n = 29; 24%), and 100% (n = 50; 42%). Preoperative symptoms included heartburn 71 (59%), early satiety 65 (54%), dyspnea 63 (52%), chest pain 48 (40%), dysphagia 56 (47%), regurgitation 47 (39%), and anemia 44 (37%). PFTs significantly improved after paraesophageal hernia repair (mean volume change, percent reference change): forced vital capacity +0.30 L,+10.3%pred; FEV1 +0.23 L,+10.4%pred (all P < .001); diffusion capacity of the lung for carbon monoxide +0.58 mL · mm Hg−1 · min−1 ( P = .004), and +2.9%pred ( P = .002). Greater improvements were documented in older patients with significant subjective respiratory symptoms and higher percent of intrathoracic stomach ( P < .01). Conclusions Paraesophageal hernia has a significant effect on respiratory function, which is largely underappreciated. This study demonstrates that these repairs can be done safely and supports routine consideration for elective repair; older patients with borderline respiratory function may achieve substantial improvements in their respiratory status and quality of life.
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