Autonomous instruments significantly expand ocean observing : an introduction to the special issue on autonomous and Lagrangian platforms and sensors (ALPS).

Author Posting. © The Oceanography Society, 2017. This article is posted here by permission of The Oceanography Society for personal use, not for redistribution. The definitive version was published in Oceanography 30, no. 2 (2017): 15–17, doi:10.5670/oceanog.2017.211.Oceanography relies heavily on observations to fuel new ideas and drive advances, creating a strong coupling between the science and the technological developments that enable new measurements. Novel observations, such as those that resolve new properties or scales, often lead to advances in understanding. Physical, biological, and chemical processes unfold over a broad range of scales—seconds to decades and millimeters to ocean basins—with critical interactions between scales. Observational studies work within a tradespace that balances spatial and temporal resolution, scope, and resource constraints. New platforms and sensors, along with the novel observational approaches they enable, address this challenge by providing access to an expanding range of temporal and spatial scales

Current measurements off the west coast of South America: November 1981 - March 1985

Several current meter moorings were deployed over the continental margin of Peru along 5° and 10°S to study the Peru current system. The observation period from November 1981 to March 1985 covered the occurrence of El Nino 1982-83. This report presents the six-hourly low-passed data sets of each mooring. Progressive vector diagrams, stick plots and time series of the east- and northward current component, temperature and pressure are shown. Histograms of speed, direction and temperature as well as a statistical page showing means and standard deviations are also included

Numerical study of circulation on the inner Amazon Shelf

Author Posting. © Springer, 2008. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Ocean Dynamics 58 (2008): 187-198, doi:10.1007/s10236-008-0139-4.We studied the circulation on the coastal domain of the Amazon Shelf by applying the hydrodynamic module of the Estuarine and Coastal Ocean Model and Sediment Transport - ECOMSED. The first barotropic experiment aimed to explain the major bathymetric effects on tides and those generated by anisotropy in sediment distribution. We analyzed the continental shelf response of barotropic tides under realistic bottom stress parametrization (Cd), considering sediment granulometry obtained from a faciologic map, where river mud deposits and reworked sediments areas are well distinguished, among others classes of sediments. Very low Cd values were set in the fluid mud regions off the Amapa coast (1.0 10-4 ), in contrast to values around 3:5 10-3 for coarser sediment regions off the Para coast. Three-dimensional experiments represented the Amazon River discharge and trade winds, combined to barotropic tide influences and induced vertical mixing. The quasi-resonant response of the Amazon Shelf to the M2 tide act on the local hydrodynamics by increasing tidal admittance, along with tidal forcing at the shelf break and extensive fluid mud regions. Harmonic analysis of modeled currents agreed well with analysis of the AMASSEDS observational data set. Tidal-induced vertical shear provided strong homogenization of threshold waters, which are subject to a kind of hydraulic control due to the topographic steepness. Ahead of the hydraulic jump, the low-salinity plume is disconnected from the bottom and acquires negative vorticity, turning southeastward. Tides act as a generator mechanism and topography, via hydraulic control, as a maintainer mechanism for the low-salinity frontal zone positioning. Tidally induced southeastward plume fate is overwhelmed by northwestward trade winds so that, along with background circulation, probably play the most important role on the plume fate and variability over the Amazon Shelf

Chronic non-transmural infarction has a delayed recovery of function following revascularization

<p>Abstract</p> <p>Background</p> <p>The time course of regional functional recovery following revascularization with regards to the presence or absence of infarction is poorly known. We studied the effect of the presence of chronic non-transmural infarction on the time course of recovery of myocardial perfusion and function after elective revascularization.</p> <p>Methods</p> <p>Eighteen patients (mean age 69, range 52-84, 17 men) prospectively underwent cine magnetic resonance imaging (MRI), delayed contrast enhanced MRI and rest/stress 99m-Tc-tetrofosmin single photon emission computed tomography (SPECT) before, one and six months after elective coronary artery bypass grafting (CABG) or percutaneous coronary intervention (PCI).</p> <p>Results</p> <p>Dysfunctional myocardial segments (n = 337/864, 39%) were classified according to the presence (n = 164) or absence (n = 173) of infarction. Infarct transmurality in dysfunctional segments was largely non-transmural (transmurality = 31 ± 22%). Quantitative stress perfusion and wall thickening increased at one month in dysfunctional segments without infarction (p < 0.001), with no further improvement at six months. Despite improvements in stress perfusion at one month (p < 0.001), non-transmural infarction displayed a slower and lesser improvement in wall thickening at one (p < 0.05) and six months (p < 0.001).</p> <p>Conclusions</p> <p>Dysfunctional segments without infarction represent repetitively stunned or hibernating myocardium, and these segments improved both perfusion and function within one month after revascularization with no improvement thereafter. Although dysfunctional segments with non-transmural infarction improved in perfusion at one month, functional recovery was mostly seen between one and six months, possibly reflecting a more severe ischemic burden. These findings may be of value in the clinical assessment of regional functional recovery in the time period after revascularization.</p

Clinical impact and 'natural' course of uncorrected tricuspid regurgitation after implantation of a left ventricular assist device: an analysis of the European Registry for Patients with Mechanical Circulatory Support (EUROMACS)

OBJECTIVES: Data on the impact and course of uncorrected tricuspid regurgitation (TR) during left ventricular assist device (LVAD) implantation are scarce and inconsistent. This study explores the clinical impact and natural course of uncorrected TR in patients after LVAD implantation. METHODS: The European Registry for Patients with Mechanical Circulatory Support was used to identify adult patients with LVAD implants without concomitant tricuspid valve surgery. A mediation model was developed to assess the association of TR with 30-day mortality via other risk factors. Generalized mixed models were used to model the course of post-LVAD TR. Joint models were used to perform sensitivity analyses. RESULTS: A total of 2496 procedures were included (median age: 56 years; men: 83%). TR was not directly associated with higher 30-day mortality, but mediation analyses suggested an indirect association via preoperative elevated right atrial pressure and creatinine (P = 0.035) and bilirubin (P = 0.027) levels. Post-LVAD TR was also associated with increased late mortality [hazard ratio 1.16 (1.06-1.3); P = 0.001]. On average, uncorrected TR diminished after LVAD implantation. The probability of having moderate-to-severe TR immediately after an implant in patients with none-to-mild TR pre-LVAD was 10%; in patients with moderate-to-severe TR pre-LVAD, it was 35% and continued to decrease in patients with moderate-to-severe TR pre-LVAD, regardless of pre-LVAD right ventricular failure or pulmonary hypertension. CONCLUSIONS: Uncorrected TR pre-LVAD and post-LVAD is associated with increased early and late mortality. Nevertheless, on average, TR diminishes progr

Psychological Stress-Induced, IDO1-Dependent Tryptophan Catabolism: Implications on Immunosuppression in Mice and Humans

It is increasingly recognized that psychological stress influences inflammatory responses and mood. Here, we investigated whether psychological stress (combined acoustic and restraint stress) activates the tryptophan (Trp) catabolizing enzyme indoleamine 2,3-dioxygenase 1(IDO1) and thereby alters the immune homeostasis and behavior in mice. We measured IDO1 mRNA expression and plasma levels of Trp catabolites after a single 2-h stress session and in repeatedly stressed (4.5-days stress, 2-h twice a day) naïve BALB/c mice. A role of cytokines in acute stress-induced IDO1 activation was studied after IFNγ and TNFα blockade and in IDO1−/− mice. RU486 and 1-Methyl-L-tryptophan (1-MT) were used to study role of glucocorticoids and IDO1 on Trp depletion in altering the immune and behavioral response in repeatedly stressed animals. Clinical relevance was addressed by analyzing IDO1 activity in patients expecting abdominal surgery. Acute stress increased the IDO1 mRNA expression in brain, lung, spleen and Peyer's patches (max. 14.1±4.9-fold in brain 6-h after stress) and resulted in a transient depletion of Trp (−25.2±6.6%) and serotonin (−27.3±4.6%) from the plasma measured 6-h after stress while kynurenine levels increased 6-h later (11.2±9.3%). IDO1 mRNA up-regulation was blocked by anti-TNFα and anti-IFNγ treatment. Continuous IDO1 blockade by 1-MT but not RU486 treatment normalized the anti-bacterial defense and attenuated increased IL-10 inducibility in splenocytes after repeated stress as it reduced the loss of body weight and behavioral alterations. Moreover, kynurenic acid which remained increased in 1-MT treated repeatedly stressed mice was identified to reduce the TNFα inducibility of splenocytes in vitro and in vivo. Thus, psychological stress stimulates cytokine-driven IDO1 activation and Trp depletion which seems to have a central role for developing stress-induced immunosuppression and behavioral alteration. Since patients showed Trp catabolism already prior to surgery, IDO is also a possible target enzyme for humans modulating immune homeostasis and mood

The formation and fate of internal waves in the South China Sea

Internal gravity waves, the subsurface analogue of the familiar surface gravity waves that break on beaches, are ubiquitous in the ocean. Because of their strong vertical and horizontal currents, and the turbulent mixing caused by their breaking, they affect a panoply of ocean processes, such as the supply of nutrients for photosynthesis1, sediment and pollutant transport2 and acoustic transmission3; they also pose hazards for man-made structures in the ocean4. Generated primarily by the wind and the tides, internal waves can travel thousands of kilometres from their sources before breaking5, making it challenging to observe them and to include them in numerical climate models, which are sensitive to their effects6,7. For over a decade, studies8-11 have targeted the South China Sea, where the oceans' most powerful known internal waves are generated in the Luzon Strait and steepen dramatically as they propagate west. Confusion has persisted regarding their mechanism of generation, variability and energy budget, however, owing to the lack of in situ data from the Luzon Strait, where extreme flow conditions make measurements difficult. Here we use new observations and numerical models to (1) show that the waves begin as sinusoidal disturbances rather than arising from sharp hydraulic phenomena, (2) reveal the existence of >200-metre-high breaking internal waves in the region of generation that give rise to turbulence levels >10,000 times that in the open ocean, (3) determine that the Kuroshio western boundary current noticeably refracts the internal wave field emanating from the Luzon Strait, and (4) demonstrate a factor-of-two agreement between modelled and observed energy fluxes, which allows us to produce an observationally supported energy budget of the region. Together, these findings give a cradle-to-grave picture of internal waves on a basin scale, which will support further improvements of their representation in numerical climate predictions