Evolution of Derwael Ice Rise in Dronning Maud Land, Antarctica, over the last millennia

Ice rises situated in the ice-shelf belt around Antarctica have a spatially confined flow regime with local ice divides. Beneath the divides, ice stratigraphy often develops arches with amplitudes that record the divide's horizontal residence time andsurface elevation changes. To investigate the evolution of Derwael Ice Rise, Dronning Maud Land, Antarctica, we combine radar and GPS data from three consecutive surveys, with a two-dimensional, full Stokes, thermomechanically-coupled, transient ice-flow model. We find that the surface mass balance (SMB) is higher on the upwind and lower on the downwind slopes. Near the crest, the SMB is anomalously low and causes arches to form in the shallow stratigraphy, observable by radar. In deeper ice, arches are consequently imprinted by both SMB and ice rheology (Raymond effect). The data show how arch amplitudes decrease as along-ridge slope increases, emphasizing that the lateral positioning of radar cross-sections is important for the arch interpretation. Using the model with three rheologies (isotropic with n = 3,4.5 and anisotropic with n = 3), we show that Derwael Ice Rise is close to steady-state, but is best explained using ice anisotropy and moderate thinning. Our preferred, albeit notunique, scenario suggests that the ice divide has existed for at least 5000 years and lowered at approximately 0.03 m a−1 over the last 3400 years. Independent of the specific thinning scenario, our modeling suggests that Derwael Ice Rise has exhibited a local flow regime at least since the Mid-Holocene

Comparison of volume-controlled and pressure-controlled ventilation during laparoscopic gastric banding in morbidly obese patients

Background There are no guidelines on ventilation modes in morbidly obese patients. We investigated the effects of volume-controlled (VCV) and pressure-controlled ventilation (PCV) on gas exchange, respiratory mechanics, and cardiovascular responses in laparoscopic gastric banding procedures. Methods After Institutional Review Board approval, 24 adult consenting patients scheduled for laparoscopic gastric banding were studied. Anesthesia was standardized using remifentanil, propofol, rocuronium, and sevoflurane. All patients started with VCV with a tidal volume of 10 ml kg(-1) ideal body weight, respiratory rate adjusted to obtain an end-tidal carbon dioxide of 35-40 mmHg, positive end-expiratory pressure of 5 cmH(2)O, an inspiratory pause of 10% and an inspiratory/expiratory ratio of 1:2. Fifteen minutes after pneumoperitoneum, the patients were randomly allocated to two groups. In Group VCV (n=12), ventilation was with the same parameters. In Group PCV (n=12), the airway pressure was set to provide a tidal volume of 10 ml kg(-1) ideal body weight without exceeding 35 cm H2O. Respiratory rate was adjusted to keep an end-tidal carbon dioxide of 35-40 mmHg. Arterial blood samples were drawn after surgical positioning and 15 min after allocation. Analysis of variance (ANOVA) was used for statistical analysis. Results With constant minute ventilation, VCV generates equal airway pressures and cardiovascular effects with a lower Pa-CO2 as compared to PCV (42.5 (5.2) mmHg versus 48.9 (4.3) mmHg, p < 0.01 ANOVA). Arterial oxygenation remained unchanged. Conclusion VCV and PCV appear to be an equally suited ventilatory technique for laparoscopic procedures in morbidly obese patients. Carbon dioxide elimination is more efficient when using VCV

Fxyd2 regulates Aδ- and C-fiber mechanosensitivity and is required for the maintenance of neuropathic pain

Identification of the molecular mechanisms governing sensory neuron subtype excitability is a key requisite for the development of treatments for somatic sensory disorders. Here, we show that the Na,K-ATPase modulator Fxyd2 is specifically required for setting the mechanosensitivity of Aδ-fiber low-threshold mechanoreceptors and sub-populations of C-fiber nociceptors, a role consistent with its restricted expression profile in the spinal somatosensory system. We also establish using the spared nerve injury model of neuropathic pain, that loss of Fxyd2 function, either constitutively in Fxyd2(-/-) mice or acutely in neuropathic rats, efficiently alleviates mechanical hypersensitivity induced by peripheral nerve lesions. The role of Fxyd2 in modulating Aδ- and C-fibers mechanosensitivity likely accounts for the anti-allodynic effect of Fxyd2 knockdown. Finally, we uncover the evolutionarily conserved restricted expression pattern of FXYD2 in human dorsal root ganglia, thus identifying this molecule as a potentially promising therapeutic target for peripheral neuropathic pain management

A capacity assessment framework for the fit-for-purpose land administration systems: the use of unmanned aerial vehicle (UAV) in Rwanda and Kenya

This article presents a novel capacity assessment framework, coined as Fit-For-Purpose capacity assessment framework (FCAF), to measure the capacity of the land administration system compliant with the Fit-For-Purpose approach. The framework incorporates legal, political, operational, social, technical, and technological capacity conditions and provides a holistic view of the capacity development pathways. The FCAF is designed by merging six capacity dimensions, namely regulations, political system, operational unit, social norms, land recording techniques, and software. FCAF systematically identifies context-specific, enabling and impeding capacity components and thus provides a basis to develop the necessary capacity development strategies and interventions. Specifically, FCAF can serve as a useful heuristic for the development of the capacity development strategies for the adaptation and sustainability of the geospatial technologies in land administration systems. In the article, by assessing the capacity needs for the adaptation of unmanned aerial vehicle (UAV) technology in Rwandese and Kenyan land administration systems, the efficacy of the FCAF is tested. The findings suggest that in Rwanda, capacity conditions are more supportive of an easier uptake of UAV. Nonetheless, weak market conditions and strict regulations concerning UAV call for attention. In Kenya, existing institutional and political challenges in the land administration system raise concerns about the reliability and attainability of UAV under the current framework conditions. Despite that, there are more supportive market conditions in Kenya in comparison to Rwanda and multiple non-governmental and private actors that can bolster the adaptation process into a more sustainable and scalable land administration system. The politics and administration of institutional chang

Prevalence of Femoroacetabular Impingement “at-risk” Radiographic Parameters in Young Asymptomatic Chinese and Caucasian Subjects

published_or_final_versio

Neck–size Distributions of Through–pores in Polymer Membranes

AbstractThe capillary flow porometry (CFP) is generally used for measuring the bubble point pressure corresponding to largest through pore–size in the membrane. In present work, the CFP technique was used for developing a methodology for determination of the neck–size distributions in the synthetic membranes. It is important as the transport flux across the membrane is controlled by the neck size of through–pores. Therefore the average, maximum and minimum pore sizes and pore–size distribution in these membranes was determined by CFP and compared with different techniques like Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM) and Molecular Weight Cut–off (MWCO). For the MWCO method, the Stokes radius of solute poly(ethylene oxide) (PEO) was calculated using the method commonly used, and also confirmed by Dynamic Light Scattering (DLS)

Characterization of primary neurospheres generated from mouse ventral rostral hindbrain

Serotonergic (5-HT) neurons of the reticular formation play a key role in the modulation of behavior, and their dysfunction is associated with severe neurological and psychiatric disorders, such as depression and schizophrenia. However, the molecular mechanisms underlying the differentiation of the progenitor cells and the specification of the 5-HT phenotype are not fully understood. A primary neurosphere cell-culture system from mouse ventral rostral hindbrain at embryonic day 12 was therefore established. The generated primary neurospheres comprised progenitor cells and fully differentiated neurons. Bromodeoxyuridine incorporation experiments in combination with immunocytochemistry for neural markers revealed the proliferation capacity of the neural multipotent hindbrain progenitors within neurospheres and their ability to differentiate toward the neuronal lineage and serotonergic phenotype. Gene expression analysis by reverse transcription with the polymerase chain reaction showed that the neurospheres were regionally specified, as reflected by the expression of the transcription factors Gata2 and Pet1. Treatment of dissociated primary neurospheres with exogenous Shh significantly increased the number of 5-HT-immunopositive cells compared with controls, whereas neutralization of endogenous Shh significantly decreased the number of 5-HT neurons. Thus, the primary neurosphere culture system presented here allows the expansion of hindbrain progenitor cells and the experimental control of their differentiation toward the serotonergic phenotype. This culture system is therefore a useful model for in vitro studies dealing with the development of 5-HT neurons