Water in Mid Ocean Ridge Basalts: Some Like it Hot, Some Like it Cold

The presence in the Earth’s mantle of even small amounts of water and other volatiles has major effects: first, it lowers drastically mantle’s viscosity, thereby facilitating convection and plate tectonics; second, it lowers the melting temperature of the rising mantle affecting the formation of the oceanic crust. H2O concentration in oceanic basalts stays below 0.2 wt% except for basalts sampled near “hot spots” that contain significantly more H2O than normal MORB, implying that their mantle plume sources are unusually H2O-rich. Basalts sampled in the Equatorial Atlantic close to the Romanche transform, a thermal minimum in the Ridge system, have a H2O content that increases as the ridge is cooled approaching the transform offset. These basalts are Na-rich, being generated by low degrees of melting of the mantle, and contain unusually high ratios of light versus heavy rare earth elements implying the presence of garnet in the melting region. H2O enrichment is due not to an unusually H2O-rich mantle source, but to a low extent of melting of the upwelling mantle, confined to a deep wet melting region. Numerical models predict that this wet melting process takes place mostly in the mantle zone of stability of garnet. This prediction is verified by the geochemistry of our basalts showing that garnet must indeed have been present in their mantle source. Thus, oceanic basalts are H2O-rich not only near “hot spots”, but also at “cold spots”

Petrology, Mineral and Isotope Geochemistry of the External Liguride Peridotites (Northern Apennines, Italy)

Mantle peridotites of the External Liguride (EL) units (Northern Apennines) represent slices of subcontinental lithospheric mantle emplaced at the surface during early stages of rifting of the Jurassic Ligurian Piemontese basin. Petrological, ion probe and isotopic investigations have been used to unravel the nature of their mantle protolith and to constrain the timing and mechanisms of their evolution. EL peridotites are dominantly fertile spinel Iherzolites partly recrystallizfd in the plagiodase Iherzplite stability field Clinopyroxenes stable in the spinel-facies assemblage have nearly fiat REE patterns (CeN/SmN=0·6-0·8) at (10-16)×C1 and high Na, Sr, Ti and Zr contents. Kaersutitic-Ti-pargasitic amphiboles also occur in the spinel-facies assemblage. Their LREE-depleted REE spectra and very low Sr, Zr and Ba contents indicate that they crystallized from hydrous fluids with low concentrations of incompatible elements. Thermometric estimates on the spinelfacies parageneses yield lithospheric equilibrium temperatures in the range 1000-1100°C, in agreement with the stability of amphibole, which implies T<1100°C. Sr and Nd isotopic compositions, determined on carefully handpicked clinopyroxene separates, plot within the depleted end of the MORB field (87Sr/86Sr=0·70222-0·70263; 143Nd/144Nd=0·513047-0·513205) similar to many subcontinental orogenic spinel Iherzolites from the western Mediterranean area (e.g. Ivrea Zpne and Lanzfl N). The interpretation of the EL Iherzolites as subcontinental lithospheric mantle is reinforced by the occurrence of one extremely depleted isotopic composition (87Sr/86Sr=0·701736; 143Nd/144Nd=0·513543). Sr and Nd model ages, calculated assuming both CHUR and DM mantle sources, range between 2·4 Ga and 780 Ma. In particular, the 1·2-Ga Sr age and the 780-Ma Nd age can be regarded as minimum ages of differentiation. The transition from spinel-to plagioclase-facies assemblage, accompanied by progressive deformation (from granular to tectonite-mylonite textures), indicate that the EL Iherzolites experienced a later, subsolidus decompressional evolution, starting from subcontinental lithospheric levels. Sm/Nd isochrons on plagioclase-clinopyroxene pairs furnish ages of ∽165 Ma. This early Jurassic subsolidus decompressional history is consistent with uplift by means of denudation in response to passive and asymmetric lithospheric extension. This is considered to be the most suitable geodynamic mechanism to account for the exposure of huge bodies of subcontinental lithospheric mantle during early stages of opening of an oceanic basi

The screening for depression and neurocognitive disorders in subjects newly diagnosed with HIV

Background Inflammatory mediators may be relevant to explain the frequent comorbidity between depression, neurocognitive disorders and HIV. HIV induces activation of inflammatory mediators, mainly cytokines, that have been involved in the onset of depression and response to antidepressant treatment. Aim To identify recurring profiles of inflammatory biomarkers subtending depression, effectiveness of antidepressants and neurocognitive disorders among HIV-infected individuals. Methods All adult newly HIV-diagnosed out-patients attending HIV clinics in three towns of Northern Italy were screened, assessed for depression and studied immunologically and for neurocognitive disorders. Results Twenty-five patients have been enrolled so far: of these, 35% were positive to PHQ-9 screening, of which 6 were positive to the diagnostic assessment for depression. No neurocognitive disorders were found among the patients. As the project will develop, it is expected that frequency of depression, neurocognitive disorders and effective antidepressant treatment will be found to correlate to the profile of immune biomarkers. These findings might help to understand the etiology of depression in HIV, and specifically the role of inflammation and immunological changes

The complex interface between economy and healthcare : An introductory overview for clinicians

In a period of generalized economic crisis, it seems particularly appropriate to try to manage a continuing growing sector such as healthcare in the best possible way. The crucial aim of optimization of available healthcare resources is obtaining the maximum possible benefit with the minimum expenditure. This has important social implications, whether individual citizens or tax-funded national health services eventually have to pay the bill. The keyword here is efficiency, which means either, maximizing the benefit from a fixed sum of money, or minimizing the resources required for a defined benefit. In order to achieve these objectives, economic evaluation is a helpful tool. Five different types of economic evaluation exist in the health-care field: cost-minimization, cost-benefit, cost-consequences, cost-effectiveness and cost-utility analysis. The objective of this narrative review is to provide an overview of the principal methods used for economic evaluation in healthcare. Economic evaluation represents a starting point for the allocation of resources, the decision of the valuable investments and the division of budgets across different health programs. Moreover, economic evaluation allows the comparison of different procedures in terms of quality of life and life expectancy, bearing in mind that cost-effectiveness is only one of multiple facets in the decision making-process. Economic evaluation is important to critically evaluate clinical interventions and ensure that we are implementing the most cost-effective management protocols. Clinicians are called to fulfill the complex task of optimizing the use of resources, and, at the same time, improving the quality of healthcare assistance

Wound care challenges in children and adults with spina bifida: An open-cohort study

Skin breakdown is a frequent concern for individuals with spina bifida. We explored wound incidence in patients with spina bifida and how it varies across a person\u27s life span and functional neurologic level. We examined the settings in which skin breakdown most commonly occurred, looking for evidence of chronic, non-healing wounds. We also sought to develop criteria to improve wound monitoring. We identified reported wound episodes in an open-cohort study over a 13-year period, examining the hospital and outpatient clinical records of spina bifida patients at Children\u27s National Medical Center (CNMC). Current age, age at wound presentation, sex, weight, functional neurologic level, wound location, setting in which the wound was acquired, the development of a chronic wound, and presence of a shunt were recorded. Of the 376 patients in our clinical population, 123 (average age: 18.8 years, range: infancy–56 years) developed a total of 375 wounds; the majority of patients who developed one wound went on to develop one or more additional wounds, and 20 patients developed chronic wounds. Our data suggest that age bracket (adolescents), wheelchair use, and bare feet, as well as possibly obesity and reduced executive functioning, are key risk factors for wound development. These findings have led to a focused effort to increase wound education and prevention. In addition we report on our early experience using a wound care specialist to champion this initiative

The SCN8A encephalopathy mutation p.Ile1327Val displays elevated sensitivity to the anticonvulsant phenytoin

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/134291/1/epi13461_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/134291/2/epi13461.pd

Birth of an ocean in the Red Sea: Initial pangs

We obtained areal variations of crustal thickness, magnetic intensity, and degree of melting of the sub- axial upwelling mantle at Thetis and Nereus Deeps, the two northernmost axial segments of initial oceanic crustal accretion in the Red Sea, where Arabia is separating from Africa. The initial emplacement of oceanic crust occurred at South Thetis and Central Nereus roughly $2.2 and$2 Ma, respectively, and is taking place today in the northern Thetis and southern Nereus tips. Basaltic glasses major and trace element com- position suggests a rift-to-drift transition marked by magmatic activity with typical MORB signature, with no contamination by continental lithosphere, but with slight differences in mantle source composition and/or potential temperature between Thetis and Nereus. Eruption rate, spreading rate, magnetic intensity, crustal thickness and degree of mantle melting were highest at both Thetis and Nereus in the very initial phases of oceanic crust accretion, immediately after continental breakup, probably due to fast mantle upwelling enhanced by an initially strong horizontal thermal gradient. This is consistent with a rift model where the lower continental lithosphere has been replaced by upwelling asthenosphere before continental rupturing, implying depth-dependent extension due to decoupling between the upper and lower lithosphere with man- tle-lithosphere-necking breakup before crustal-necking breakup. Independent along-axis centers of upwell- ing form at the rifting stage just before oceanic crust accretion, with buoyancy-driven convection within a hot, low viscosity asthenosphere. Each initial axial cell taps a different asthenospheric source and serves as nucleus for axial propagation of oceanic accretion, resulting in linear segments of spreading

The role of cryptotephra in refining the chronology of Late Pleistocene human evolution and cultural change in North Africa

© 2014.Sites in North Africa hold key information for dating the presence of Homo sapiens and the distribution of Middle Stone Age (MSA), Middle Palaeolithic (MP) and Later Stone Age (LSA) cultural activity in the Late Pleistocene. Here we present new and review recently published tephrochronological evidence for five cave sites in North Africa with long MSA/MP and LSA cultural sequences. Four tephra horizons have been identified at the Haua Fteah (Cyrenaica, Libya). They include cryptotephra evidence for the Campanian Ignimbrite (CI) eruption dating to ~39 ka that allows correlation with other Palaeolithic sequences in the eastern Mediterranean and as far north as Russia. Cryptotephra have also been recorded from the Moroccan sites of Taforalt, Rhafas and Dar es-Soltane 1. At Taforalt the geochemical composition suggests a provenance in the Azores, while examples from Sodmein (Egypt) appear to derive from central Anatolia and another unknown source. In these latter examples chemical compositional data from relevant proximal volcanic centres is currently lacking so the identification of tephra in layers of known age and cultural association provides the first reliable age determinations for distal volcanic events and their geographical extent. The future potential for tephrochronological research in North Africa is also discussed

Is Shifting to a Progestin Worthwhile When Estrogen-Progestins Are Inefficacious for Endometriosis-Associated Pain?

The purpose of this study was to assess the proportion of patients satisfied with their treatment after a change from a low-dose oral contraceptive (OC) to norethisterone acetate (NETA) because of inefficacy of OC on pain symptoms. To this end, prospective, self-controlled study was conducted on 153 women using OC as a treatment for endometriosis and with persistence of one or more moderate or severe pain symptoms. At baseline and during 12 months after a shift from OC to oral NETA, 2.5 mg/d, pelvic pain was measured by means of a 0- to 10-point numerical rating scale and a multidimensional categorical rating scale. Variations in health-related quality of life, psychological status, and sexual function were also evaluated with validated scales. At the end of the study period, participants indicated the degree of satisfaction with their treatment according to a 5-degree scale from very satisfied to very dissatisfied. A total of 28 women dropped out of the study, the main reason was intolerable side effects (n = 15). At 12-month assessment, 70% of participants were very satisfied or satisfied with NETA treatment (intention-to-treat analysis). Statistically significant improvements were observed in health-related quality of life, psychological status, and sexual function. At per-protocol analysis, almost half of the patients (58/125) reported suboptimal drug tolerability. However, complaints were not severe enough to cause dissatisfaction, drug discontinuation, or request for surgery. These encouraging results could be used to counsel women with symptomatic endometriosis not responding to OC and to inform their decisions on modifications of disease management