Major abdominal surgery in Jehovah’s Witnesses

Introduction Patients who are Jehovah’s Witnesses pose difficult ethical and moral dilemmas for surgeons because of their refusal to receive blood and blood products. This article outlines the personal experiences of six Jehovah’s Witnesses who underwent major abdominal surgery at a single institution and also summarises the literature on the perioperative care of these patients. Methods The patients recorded their thoughts and the dilemmas they faced during their surgical journey. We also reviewed the recent literature on the ethical principles involved in treating such patients and strategies recommended to make surgery safer. Results All patients were supported in their decision making by the clinical team and the Hospital Liaison Committee for Jehovah’s Witnesses. The patients recognised the ethical and moral difficulties experienced by clinicians in this setting. However, they described taking strength from their belief in Jehovah. A multitude of techniques are available to minimise the risk associated with major surgery in Jehovah’s Witness patients, many of which have been adopted to minimise unnecessary use of blood products in general. Nevertheless, the risks of catastrophic haemorrhage and consequent mortality remain an unresolved issue for the treating team. Conclusions Respect for a patient’s autonomy in this setting is the overriding ethical principle, with detailed discussion forming an important part of the preparation of a Jehovah’s Witness for major abdominal surgery. Clinicians must be diligent in the documentation of the patient’s wishes to ensure all members of the team can abide by these

Parametric Amplification of Nonlinear Response of Single Crystal Niobium

Giant enhancement of the nonlinear response of a single crystal Nb sample, placed in {\it a pumping ac magnetic field}, has been observed experimentally. The experimentally observed amplitude of the output signal is about three orders of magnitude higher than that seen without parametric pumping. The theoretical analysis based on the extended double well potential model provides a qualitative explanation of the experimental results as well as new predictions of two bifurcations for specific values of the pumping signal.Comment: 6 pages, 10 figure

Characterization of the stretched exponential trap-time distributions in one-dimensional coupled map lattices

Stretched exponential distributions and relaxation responses are encountered in a wide range of physical systems such as glasses, polymers and spin glasses. As found recently, this type of behavior occurs also for the distribution function of certain trap time in a number of coupled dynamical systems. We analyze a one-dimensional mathematical model of coupled chaotic oscillators which reproduces an experimental set-up of coupled diode-resonators and identify the necessary ingredients for stretched exponential distributions.Comment: 8 pages, 8 figure

Postseismic Deformation Following the 2015 M_w7.8 Gorkha (Nepal) Earthquake: New GPS Data, Kinematic and Dynamic Models, and the Roles of Afterslip and Viscoelastic Relaxation

We report Global Positioning System (GPS) measurements of postseismic deformation following the 2015 M_w7.8 Gorkha (Nepal) earthquake, including previously unpublished data from 13 continuous GPS stations installed in southern Tibet shortly after the earthquake. We use variational Bayesian Independent Component Analysis (vbICA) to extract the signal of postseismic deformation from the GPS time series, revealing a broad displacement field extending >150 km northward from the rupture. Kinematic inversions and dynamic forward models show that these displacements could have been produced solely by afterslip on the Main Himalayan Thrust (MHT) but would require a broad distribution of afterslip extending similarly far north. This would require the constitutive parameter (a − b)σ to decrease northward on the MHT to ≤0.05 MPa (an extreme sensitivity of creep rate to stress change) and seems unlikely in light of the low interseismic coupling and high midcrustal temperatures beneath southern Tibet. We conclude that the northward reach of postseismic deformation more likely results from distributed viscoelastic relaxation, possibly in a midcrustal shear zone extending northward from the seismogenic MHT. Assuming a shear zone 5–20 km thick, we estimate an effective shear‐zone viscosity of ~3·10¹⁶–3·10¹⁷ Pa·s over the first 1.12 postseismic years. Near‐field deformation can be more plausibly explained by afterslip itself and implies (a − b)σ ~ 0.5–1 MPa, consistent with other afterslip studies. This near‐field afterslip by itself would have re‐increased the Coulomb stress by ≥0.05 MPa over >30% of the Gorkha rupture zone in the first postseismic year, and deformation further north would have compounded this reloading

Musculoskeletal deformities following repair of large congenital diaphragmatic hernias

Split-abdominal wall muscle flap Purpose: Large congenital diaphragmatic hernias (CDH) can be repaired with either a muscle flap or prosthetic patch. The purpose of this study was to assess the frequency and severity of scoliosis, chest wall, and abdominal wall deformities following these repairs. Methods: Neonates who underwent CDH repair (1989-2012) were retrospectively reviewed. We then validated our retrospective review by comparing results of a focused radiologic evaluation and clinical examination of patients with large defects seen in prospective follow-up clinic. Tests for association were made using Fisher's exact test. Results: 236 patients survived at least 1 year. Of these patients, 30 had a muscle flap, and 13 had a patch repair. Retrospectively, we identified pectus in 9% of primary repairs, 47% of flap repairs, and 54% of patch repairs. We identified scoliosis in 7% of primary repairs, 13% of flap repairs, and 15% of patch repairs. Prospectively, 75% of flap patients and 67% of patch patients had pectus and 13% of flap patients and 33% of patch patients had scoliosis. There was no significant difference between flap and patch patients. Conclusions: Scoliosis and pectus deformity were common in children with large CDH. The operative technique did not appear to affect the incidence of subsequent skeletal deformity. © 2014 Elsevier Inc. All rights reserved. Large congenital diaphragmatic hernias (CDHs) require repair with either a patch or an autologous tissue transfer. Repair with a prosthetic patch is the technique used by most surgeons Methods Study population After obtaining approval from the Institutional Review Board, a retrospective review of all children with CDH repair at our regional tertiary care children's hospital from 1989 to 2012 was performed. The patients were categorized by the technique of their repair. Repair types included primary repair, split abdominal wall muscle flap and synthetic patch. Paper and electronic medical records were reviewed to obtain demographic data, and diagnosis of skeletal deformities as well as any treatment for the skeletal deformities. Electronic charts were searched for the key words "pectus" and "scoliosis," and those specific notes were reviewed. These diagnoses were made by a variety of physicians including radiologists, orthopedists and primary care physicians and were not always confirmed by a focused follow-up visit by a pediatric surgeon. In order to check the validity of our retrospective review, patients with large defects were seen prospectively for focused follow-up and a single pediatric radiologist (G.H.) reviewed the most current chest radiograph to evaluate for scoliosis greater than 10 degrees. The results of follow-up were correlated with our retrospective review

Organic nitrate and secondary organic aerosol yield from NO3 oxidation of ß-pinene evaluated using a gas-phase kinetics/aerosol partitioning model

The yields of organic nitrates and of secondary organic aerosol (SOA) particle formation were measured for the reaction NO3+beta-pinene under dry and humid conditions in the atmosphere simulation chamber SAPHIR at Research Center Julich. These experiments were conducted at low concentrations of NO3 (NO3+N2O5 < 10 ppb) and beta-pinene (peak similar to 15 ppb), with no seed aerosol. SOA formation was observed to be prompt and substantial (similar to 50% mass yield under both dry conditions and at 60% RH), and highly correlated with organic nitrate formation. The observed gas/aerosol partitioning of organic nitrates can be simulated using an absorptive partitioning model to derive an estimated vapor pressure of the condensing nitrate species of p(vap) similar to 5x10(-6) Torr (6.67x10(-4) Pa), which constrains speculation about the oxidation mechanism and chemical identity of the organic nitrate. Once formed the SOA in this system continues to evolve, resulting in measurable aerosol volume decrease with time. The observations of high aerosol yield from NOx-dependent oxidation of monoterpenes provide an example of a significant anthropogenic source of SOA from biogenic hydrocarbon precursors. Estimates of the NO3+beta-pinene SOA source strength for California and the globe indicate that NO3 reactions with monoterpenes are likely an important source (0.5-8% of the global total) of organic aerosol on regional and global scales

A versatile vacuum ultraviolet ion source for reduced pressure bipolar chemical ionization mass spectrometry

We present the development of a chemical ionization mass spectrometer ion source specifically designed for in situ measurements of trace gases in the upper troposphere and lower stratosphere. The ion source utilizes a commercially available photoionization krypton lamp, primarily emitting photons in the vacuum ultraviolet (VUV) region at wavelengths of 124 and 117&thinsp;nm (corresponding to energies of 10 and 10.6&thinsp;eV, respectively), coupled to a commercially available Vocus proton transfer reaction mass spectrometer. The VUV ion source can produce both negative and positive reagent ions; however, here we primarily focus on generating iodide anions (I&minus;). The instrument's drift tube (also known as ion&ndash;molecule reactor) operates at pressures between 2 and 10&thinsp;mbar, which facilitates ambient sampling at atmospheric pressures as low as 50&thinsp;mbar. The low operating pressure reduces secondary ion chemistry that can occur in iodide chemical ionization mass spectrometry (CIMS). It also allows the addition of water vapor to the drift tube to exceed typical ambient humidity by more than 1 order of magnitude, significantly reducing ambient humidity dependence of sensitivities. An additional benefit of this ion source and drift tube is a 10- to 100-fold reduction in nitrogen consumed during operation relative to standard I&minus; ion sources, resulting in significantly reduced instrument weight and operational costs. In iodide mode, sensitivities of 76&thinsp;cps&thinsp;ppt&minus;1 for nitric acid, 35&thinsp;cps&thinsp;ppt&minus;1 for Br2 and 8.9&thinsp;cps&thinsp;ppt&minus;1 for Cl2 were achieved. Lastly, we demonstrate that this ion source can generate benzene () and ammonium () reagent ions to expand the number of detected atmospheric trace gases.</p

The Role of Sulfur Dioxide in Stratospheric Aerosol Formation Evaluated by Using in situ Measurements in the Tropical Lower Stratosphere

Stratospheric aerosols (SAs) are a variable component of the Earth\u27s albedo that may be intentionally enhanced in the future to offset greenhouse gases (geoengineering). The role of tropospheric-sourced sulfur dioxide (SO2) in maintaining background SAs has been debated for decades without in situ measurements of SO2 at the tropical tropopause to inform this issue. Here we clarify the role of SO2 in maintaining SAs by using new in situ SO2 measurements to evaluate climate models and satellite retrievals. We then use the observed tropical tropopause SO2 mixing ratios to estimate the global flux of SO2 across the tropical tropopause. These analyses show that the tropopause background SO2 is about 5 times smaller than reported by the average satellite observations that have been used recently to test atmospheric models. This shifts the view of SO2 as a dominant source of SAs to a near-negligible one, possibly revealing a significant gap in the SA budget. ©2017. American Geophysical Union