Flow dynamics and mixing processes in hydraulic jump arrays: Implications for channel-lobe transition zones

A detailed field investigation of a saline gravity current in the southwest Black Sea has enabled the first complete analysis of three-dimensional flow structure and dynamics of a series of linked hydraulic jumps in stratified, density-driven, flows. These field observations were collected using an acoustic Doppler current profiler mounted on an autonomous underwater vehicle, and reveal that internal mixing processes in hydraulic jumps, including flow expansion and recirculation, provide a previously unrecognised mechanism for grain-size sorting and segregation in stratified density-driven flows. Field observations suggest a newly identified type of hydraulic jump, that is a stratified low Froude number (< 1.5–2) subaqueous hydraulic jump, with an enhanced ability to transport sediment downstream of the jump, in comparison to hydraulic jumps in other subaerial and submarine flows. These novel field data underpin a new process-based conceptual model of channel lobe transition zones (CLTZs) that explains the scattered offset nature of scours within such settings, the temporal variations in infill and erosion between adjacent scours, how bed shear stresses are maintained across the CLTZ, and why the locus of deposition is so far downstream of the scour zone

Spatial and temporal analysis of extreme sea level and storm surge events around the coastline of the UK

In this paper we analyse the spatial footprint and temporal clustering of extreme sea level and skew surge events around the UK coast over the last 100 years (1915-2014). The vast majority of the extreme sea level events are generated by moderate, rather than extreme skew surges, combined with spring astronomical high tides. We distinguish four broad categories of spatial footprints of events and the distinct storm tracks that generated them. There have been rare events when extreme levels have occurred along two unconnected coastal regions during the same storm. The events that occur in closest succession (< 4 days) typically impact different stretches of coastline. The spring/neap tidal cycle prevents successive extreme sea level events from happening within 4-8 days. Finally, the 2013/14 season was highly unusual in the context of the last 100 years from an extreme sea level perspective

Spontaneous splenic rupture in an active duty Marine upon return from Iraq: a case report

<p>Abstract</p> <p>Introduction</p> <p>Atraumatic splenic rupture is a rare event that has been associated with several infectious disease processes. In the active duty military population, potential exposure to these pathogens is significant. Here we discuss the case of an active duty Marine with spontaneous splenic rupture upon return from a six-month deployment in Iraq.</p> <p>Case presentation</p> <p>A previously healthy 30-year-old Caucasian male active duty Marine presented with abdominal pain, fever and diarrhea after deployment to Iraq in support of Operation Iraqi Freedom. Based on clinical and radiographic evidence, a diagnosis of spontaneous splenic rupture was ultimately suspected. After exploratory laparotomy with confirmation of rupture, splenectomy was performed, and the patient made a full, uneventful recovery. Histopathologic examination revealed mild splenomegaly with a ruptured capsule of undetermined cause.</p> <p>Conclusion</p> <p>Spontaneous splenic rupture is a rare event that may lead to life-threatening hemorrhage if not diagnosed and treated quickly. Although the cause of this patient's case was unknown, atraumatic splenic rupture has been associated with a variety of infectious diseases and demonstrates some risks the active duty military population may face while on deployment. Having an awareness of these pathogens and their role in splenic rupture, clinicians caring for military personnel must be prepared to recognize and treat this potentially fatal complication.</p

Evaluation of phenolic contents and antioxidant activity of various solvent extracts of Sonchus asper (L.) Hill

<p>Abstract</p> <p>Background</p> <p><it>Sonchus asper </it>(SA) is traditionally used for the treatment of various ailments associated with liver, lungs and kidneys. This study was aimed to investigate the therapeutic potential of nonpolar (hexane, SAHE; ethyl acetate, SAEE and chloroform, SACE) and polar (methanol, SAME) crude extracts of the whole plant.</p> <p>Methods</p> <p>To achieve these goals, several parameters including free-radical (DPPH^•, ABTS^•+, H₂O₂and ^•OH) scavenging, iron chelating activity, scavenging of superoxide radicals, total flavonoids and total phenolic content (TPC) were examined.</p> <p>Results</p> <p>The SA extracts presented a remarkable capacity to scavenge all the tested reactive species with IC₅₀values being found at the μg ⁄ ml level. The SAME was shown to have the highest TPCs while lowest IC₅₀values for the DPPH^•, ABTS^•+radical scavenging capacities and iron chelating scavenging efficiency, moreover, SAME had best activities in scavenging of superoxide radicals and hydrogen peroxide as well as potently scavenged the hydroxyl radicals.</p> <p>Conclusion</p> <p>These results suggest the potential of <it>S. asper </it>as a medicine against free-radical-associated oxidative damage.</p

Effects of selective serotonin reuptake inhibitor treatment on plasma oxytocin and cortisol in major depressive disorder

Background: Oxytocin is known for its capacity to facilitate social bonding, reduce anxiety and for its actions on the stress hypothalamopituitary adrenal (HPA) axis. Since oxytocin can physiologically suppress activity of the HPA axis, clinical applications of this neuropeptide have been proposed in conditions where the function of the HPA axis is dysregulated. One such condition is major depressive disorder (MDD). Dysregulation of the HPA system is the most prominent endocrine change seen with MDD, and normalizing the HPA axis is one of the major targets of recent treatments. The potential clinical application of oxytocin in MDD requires improved understanding of its relationship to the symptoms and underlying pathophysiology of MDD. Previous research has investigated potential correlations between oxytocin and symptoms of MDD, including a link between oxytocin and treatment related symptom reduction. The outcomes of studies investigating whether antidepressive treatment (pharmacological and non-pharmacological) influences oxytocin concentrations in MDD, have produced conflicting outcomes. These outcomes suggest the need for an investigation of the influence of a single treatment class on oxytocin concentrations, to determine whether there is a relationship between oxytocin, the HPA axis (e.g., oxytocin and cortisol) and MDD. Our objective was to measure oxytocin and cortisol in patients with MDD before and following treatment with selective serotonin reuptake inhibitors, SSRI. Method: We sampled blood from arterial plasma. Patients with MDD were studied at the same time twice; pre- and post- 12 weeks treatment, in an unblinded sequential design (clinicaltrials.govNCT00168493). Results: Results did not reveal differences in oxytocin or cortisol concentrations before relative to following SSRI treatment, and there were no significant relationships between oxytocin and cortisol, or these two physiological variables and psychological symptom scores, before or after treatment. Conclusions: These outcomes demonstrate that symptoms of MDD were reduced following effective treatment with an SSRI, and further, stress physiology was unlikely to be a key factor in this outcome. Further research is required to discriminate potential differences in underlying stress physiology for individuals with MDD who respond to antidepressant treatment, relative to those who experience treatment resistance.Charlotte Keating, Tye Dawood, David A Barton, Gavin W Lambert and Alan J Tilbroo

The effect of atmospheric acid processing on the global deposition of bioavailable phosphorus from dust

The role of dust as a source of bioavailable phosphorus (Bio-P) is quantified using a new parameterization for apatite dissolution in combination with global soil data maps and a global aerosol transport model. Mineral dust provides 31.2 Gg-P yr-1 of Bio-P to the oceans, with 14.3 Gg-P yr-1 from labile P present in the dust, and an aditional 16.9 Gg-P yr from acid dissolution of apatite in the atmosphere, representing an increase of 120%. The North Atlantic, north west Pacific, and Mediterranean Sea are identified as important sites of Bio-P deposition from mineral dust. The acid dissolution process increases the fraction of total-P that is bioavailable from ~10% globally from the labile pool to 23% in the Atlantic Ocean, 45% in the Pacific Ocean, and 21% in the Indian Ocean, with an ocean global mean value of 22%. Strong seasonal variations, especially in the North Pacific, northwest Atlantic, and Indian Ocean, are driven by large-scale meteorology and pollution sources from industrial and biomass-burning regions. Globally constant values of total-P content and bioavailable fraction used previously do not capture the simulated variability. We find particular sensitivity to the representation of particle-to-particle variability of apatite, which supplies Bio-P through acid-dissolution, and calcium carbonate, which helps to buffer the dissolution process. A modest 10% external mixing results in an increase of Bio-P deposition by 18%. The total Bio-P calculated here (31.2 Gg-P yr-1) represents a minimum compared to previous estimates due to the relatively low total-P in the global soil map used

Physical forcing and physical/biochemical variability of the Mediterranean Sea: a review of unresolved issues and directions for future research

This paper is the outcome of a workshop held in Rome in November 2011 on the occasion of the 25th anniversary of the POEM (Physical Oceanography of the Eastern Mediterranean) program. In the workshop discussions, a number of unresolved issues were identified for the physical and biogeochemical properties of the Mediterranean Sea as a whole, i.e., comprising the Western and Eastern sub-basins. Over the successive two years, the related ideas were discussed among the group of scientists who participated in the workshop and who have contributed to the writing of this paper. Three major topics were identified, each of them being the object of a section divided into a number of different sub-sections, each addressing a specific physical, chemical or biological issue: 1. Assessment of basin-wide physical/biochemical properties, of their variability and interactions. 2. Relative importance of external forcing functions (wind stress, heat/moisture fluxes, forcing through straits) vs. internal variability. 3. Shelf/deep sea interactions and exchanges of physical/biogeochemical properties and how they affect the sub-basin circulation and property distribution. Furthermore, a number of unresolved scientific/methodological issues were also identified and are reported in each sub-section after a short discussion of the present knowledge. They represent the collegial consensus of the scientists contributing to the paper. Naturally, the unresolved issues presented here constitute the choice of the authors and therefore they may not be exhaustive and/or complete. The overall goal is to stimulate a broader interdisciplinary discussion among the scientists of the Mediterranean oceanographic community, leading to enhanced collaborative efforts and exciting future discoveries

Does the oxytocin receptor polymorphism (rs2254298) confer 'vulnerability' for psychopathology or 'differential susceptibility'? insights from evolution

The diathesis-stress model of psychiatric conditions has recently been challenged by the view that it might be more accurate to speak of 'differential susceptibility' or 'plasticity' genes, rather than one-sidedly focusing on individual vulnerability. That is, the same allelic variation that predisposes to a psychiatric disorder if associated with (developmentally early) environmental adversity may lead to a better-than-average functional outcome in the same domain under thriving (or favourable) environmental conditions. Studies of polymorphic variations of the serotonin transporter gene, the monoamino-oxidase-inhibitor A coding gene or the dopamine D4 receptor gene indicate that the early environment plays a crucial role in the development of favourable versus unfavourable outcomes. Current evidence is limited, however, to establishing a link between genetic variation and behavioural phenotypes. In contrast, little is known about how plasticity may be expressed at the neuroanatomical level as a 'hard-wired' correlate of observable behaviour. The present review article seeks to further strengthen the argument in favour of the differential susceptibility theory by incorporating findings from behavioural and neuroanatomical studies in relation to genetic variation of the oxytocin receptor gene. It is suggested that polymorphic variation at the oxytocin receptor gene (rs2254298) is associated with sociability, amygdala volume and differential risk for psychiatric conditions including autism, depression and anxiety disorder, depending on the quality of early environmental experiences. Seeing genetic variation at the core of developmental plasticity can explain, in contrast to the diathesis-stress perspective, why evolution by natural selection has maintained such 'risk' alleles in the gene pool of a population