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Humanitarian surgery is essential to surgical care in limited resource settings. The difficulties associated with resource constraints necessitate special training for civilian surgeons to provide care in these situations. Specific training or curricula for humanitarian surgeons are not well described in the literature. This scoping review summarizes the existing literature and identifies areas for potential improvement. A review of articles describing established courses for civilian surgeons interested in humanitarian surgery, as well as those describing training of civilian surgeons in conflict zones, was performed. A total of 4808 abstracts were screened by two independent reviewers, and 257 abstracts were selected for full-text review. Articles describing prehospital care and military experience were excluded from the full-text review. Of the eight relevant full texts, 10 established courses for civilian surgeons were identified. Cadaver-based teaching combined with didactics were the most common course themes. Courses provided technical education focused on the management of trauma and burns as well as emergencies in orthopedics, neurosurgery, obstetrics, and gynecology. Other courses were in specialty surgery, mainly orthopedics. Two fellowship programs were identified, and these provide a different model for training humanitarian surgeons. Humanitarian surgery is often practiced in austere environments, and civilian surgeons must be adequately trained to first do no harm. Current programs include cadaver-based courses focused on enhancing trauma surgery and surgical subspecialty skills, with adjunctive didactics covering resource allocation in austere environments. Fellowships programs may serve as an avenue to provide a more standardized education and a reliable pipeline of global surgeons. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Discrete component fitting of multi-dimensional NMR data. • Alternative to linear methods using regularization. • New algorithm determines optimum number of components. • Avoids data compression in real-time data processing. Abstract We present a nonlinear inversion method for generating sparse solutions to the Fredholm Integral equation describing two-dimensional distributions of nuclear magnetic resonance (NMR) relaxation times or diffusion coefficients. Our greedy variational method approximates the distribution of exponential rate constants using a sum of Dirac delta functions, which constitute our dictionary elements. The greedy nature of the method promotes sparsity in the representation by iteratively increasing the number of terms. The variational component estimates the parameters of the Dirac delta functions from a continuum at each iteration by reducing the least squares misfit to the data. Unlike sparsity promoting linearized inversion methods, where the dictionary is fixed and can exponentially grow in the case of multiple variables or when searching for higher resolution, the greedy component of our method aims to keep the dictionary small while the variational component keeps the dictionary dynamic. We demonstrate our method with synthetic data and experimental measurements of T 1 - T 2 correlations of liquid-saturated porous rocks. The sparsity of the approximate solutions is ideal for real-time processing and transmission in remote or mobile NMR applications such as well logging. [ABSTRACT FROM AUTHOR]

We search for meridional variation in the abundance of CH 3 D relative to CH 4 on Titan using near-IR spectra obtained with NIRSPAO at Keck, which have a photon-limited signal-to-noise ratio of ∼50. Our observations can rule out a larger than 10% variation in the column of CH 3 D below 50 km. The preferential condensation of the heavy isotopologues will fractionate methane by reducing CH 3 D in the remaining vapor, and therefore these observations place limits on the amount of condensation that occurs in the troposphere. While previous estimates of CH 3 D fractionation on Titan have estimated an upper limit of − 6‰, assuming a solid condensate, we consider more recent laboratory data for the equilibrium fractionation over liquid methane, and use a Rayleigh distillation model to calculate fractionation in an ascending parcel of air that is following a moist adiabat. We find that deep, precipitating convection can enhance the fractionation of the remaining methane vapor by − 10 to − 40‰, depending on the final temperature of the rising parcel. By relating fractionation of our reference parcel model to the pressure level where the moist adiabat achieves the required temperature, we argue that the measured methane fractionation constrains the outflow level for a deep convective event. Observations with a factor of at least 4–6 times larger signal-to-noise are required to detect this amount of fractionation, depending on the altitude range over which the outflow from deep convection occurs. [ABSTRACT FROM AUTHOR]

The spatial distribution of the tropospheric methane on Titan was measured using near-infrared spectroscopy. Ground-based observations at 1.5 μ m (H-band) were performed during the same night using instruments with adaptive optics at both the W.M. Keck Observatory and at the Paranal Observatory on 17 July 2014 UT. The integral field observations with SINFONI on the VLT covered the entire H-band at moderate resolving power, R = λ / Δ λ ≈ 1500 , while the Keck observations were performed with NIRSPAO near 1.5525 μ m at higher resolution, R ≈ 25 , 000 . The moderate resolution observations are used for flux calibration and for the determination of model parameters that can be degenerate in the interpretation of high resolution spectra. Line-by-line calculations of CH 4 and CH 3 D correlated k distributions from the HITRAN 2012 database were used, which incorporate revised line assignments near 1.5 μ m . We fit the surface albedo and aerosol distributions in the VLT SINFONI observations that cover the entire H-band window and used these quantities to constrain the models of the high-resolution Keck NIRSPAO spectra when retrieving the methane abundances. Cassini VIMS images of the polar regions, acquired on 20 July 2014 UT, are used to validate the assumption that the opacity of tropospheric aerosol is relatively uniform below 10 km. We retrieved methane abundances at latitudes between 42°S and 80°N. The tropospheric methane in the Southern mid-latitudes was enhanced by a factor of ∼10–40% over the nominal profile that was measured using the GCMS on Huygens . The northern hemisphere had ∼90% of the nominal methane abundance up to polar latitudes (80°N). These measurements suggest that a source of saturated polar air is equilibrating with dryer conditions at lower latitudes. [ABSTRACT FROM AUTHOR]

Idealized Earth-like general circulation models (GCMs) have been extensively used to study superrotation on so-called "slowly rotating" bodies like Venus and Titan, however they tend to have difficulty producing superrotation if only the rotation rate is reduced to Titan- or Venus-like values. The Rossby number, RO = UI2ΩL, which characterizes the influence of rotation on the circulation, is small for Earth but large for both Venus and Titan. However, the differences in other nondimensional control parameters are often ignored in idealized planetary circulation studies. In this study we use a simplified Earth-like GCM to demonstrate the importance of the other nondimensional parameters in obtaining a superrotating flow, and identify the wave-modes responsible for generating and maintaining superrotation. We show that superrotation only emerges on a planet of slow rotation rate if the atmospheric thermal inertia is simultaneously increased; alternatively, superrotation is obtained if the only planetary radius is reduced. When only the rotation rate is reduced, a nearly axisymmetric circulation with intense Hadley cells is produced that prevents strong and persistent winds over the equator. The mechanism for generating and maintaining superrotation in the model involves a coupling between equatorial and high-latitude waves. However, the generation involves equatorial Kelvin-like waves and maintenance involves equatorial Rossby-like waves. [ABSTRACT FROM AUTHOR]

Highlights: [•] Rapid measurements are implemented at low field. [•] Relaxation time is correlated against magnetic susceptibility contrast. [•] Microscopic sample heterogeneity is measured. [•] Macroscopic structural heterogeneity assessed with rapid profiling. [•] Methods demonstrated on sandstone core plugs. [ABSTRACT FROM AUTHOR]

Abstract: A number of synchronous moons are thought to harbor water oceans beneath their outer ice shells. A subsurface ocean frictionally decouples the shell from the interior. This has led to proposals that a weak tidal or atmospheric torque might cause the shell to rotate differentially with respect to the synchronously rotating interior. Applications along these lines have been made to Europa and Titan. However, the shell is coupled to the ocean by an elastic torque. As a result of centrifugal and tidal forces, the ocean would assume an ellipsoidal shape with its long axis aligned toward the parent planet. Any displacement of the shell away from its equilibrium position would induce strains thereby increasing its elastic energy and giving rise to an elastic restoring torque. In the investigation reported on here, the elastic torque is compared with the tidal torque acting on Europa and the atmospheric torque acting on Titan. Regarding Europa, it is shown that the tidal torque is far too weak to produce stresses that could fracture the ice shell, thus refuting an idea that has been widely advocated. Instead, it is suggested that the cracks arise from time-dependent stresses due to non-hydrostatic gravity anomalies from tidally driven, episodic convection in the satellite’s interior. Two years of Cassini RADAR observations of Titan’s surface have been interpreted as implying an angular displacement of ∼0.24° relative to synchronous rotation. Compatibility of the amplitude and phase of the observed non-synchronous rotation with estimates of the atmospheric torque requires that Titan’s shell be decoupled from its interior. We find that the elastic torque balances the seasonal atmospheric torque at an angular displacement ≲0.05°, effectively coupling the shell to the interior. Moreover, if Titan’s surface were spinning faster than synchronous, the tidal torque tending to restore synchronous rotation would almost certainly be larger than the atmospheric torque. There must either be a problem with the interpretation of the radar observations, or with our basic understanding of Titan’s atmosphere and/or interior. [Copyright &y& Elsevier]

Abstract: We identify mechanisms controlling the distribution of methane convection and large-scale circulation in a simplified, axisymmetric model atmosphere of Titan forced by gray radiation and moist (methane) convection. The large-scale overturning circulation, or Hadley cell, is global in latitudinal extent and provides fundamental control of precipitation and tropospheric winds. The precipitating, large-scale updraft regularly oscillates in latitude with seasons. The distance of greatest poleward excursion of the Hadley cell updraft is set by the mass of the convective layer of the atmosphere; convection efficiently communicates seasonal warming of the surface through the cold and dense lower atmosphere, increasing the heat capacity of the system. The presence of deep, precipitating convection introduces three effects relative to the case with no methane latent heating: (1) convection is narrowed and enhanced in the large-scale updraft of the Hadley cell; (2) the latitudinal amplitude of Hadley cell updraft oscillations is decreased; and (3) a time lag is introduced. These effects are observable in the location and timing of convective methane clouds in Titan’s atmosphere as a function of season. A comparison of simulations over a range of convective regimes with available observations suggest methane thermodynamic–dynamic feedback is important in the Titan climate. [Copyright &y& Elsevier]

The mouse submandibular gland (SMG) epithelium undergoes extensive morphogenetic branching during embryonic development as the first step in the establishment of its glandular structure. However, the specific signaling pathways required for SMG branching morphogenesis are not well understood. Using E13 mouse SMG organ cultures, we showed that inhibitors of phosphatidylinositol 3-kinase (PI 3-kinase), wortmannin and LY294002, substantially inhibited branching morphogenesis in SMG. Branching morphogenesis of epithelial rudiments denuded of mesenchyme was inhibited similarly, indicating that PI 3-kinase inhibitors act directly on the epithelium. Immunostaining and Western analysis demonstrated that the p85 isoform of PI 3-kinase is expressed in epithelium at levels higher than in the mesenchyme. A target of PI 3-kinase, Akt/protein kinase B (PKB), showed decreased phosphorylation at Ser473 by Western analysis in the presence of PI 3-kinase inhibitors. The major lipid product of PI 3-kinase, phosphatidylinositol 3,4,5-trisphosphate (PIP3), was added exogenously to SMG via a membrane-transporting carrier in the presence of PI 3-kinase inhibitors and was found to stimulate cleft formation, the first step of branching morphogenesis. Together, these data indicate that PI 3-kinase plays a role in the regulation of epithelial branching morphogenesis in mouse SMG acting through a PIP3 pathway. [Copyright &y& Elsevier]