The origin of bulk silicate Earth carbon inventory is unknown and the fate of carbon during the early Earth differentiation and core formation is a missing link in the evolution of the terrestrial ...carbon cycle. Here we present high pressure (P)–temperature (T) experiments that offer new constraints upon the partitioning of carbon between metallic and silicate melt in a shallow magma ocean. Experiments were performed at 1–5GPa, 1600–2100°C on mixtures of synthetic or natural silicates (tholeiitic basalt/alkali basalt/komatiite/fertile peridotite) and Fe–Ni–C±Co±S contained in graphite or MgO capsules. All the experiments produced immiscible Fe-rich metallic and silicate melts at oxygen fugacity (fO2) between ∼IW-1.5 and IW-1.9. Carbon and hydrogen concentrations of basaltic glasses and non-glassy quenched silicate melts were determined using secondary ionization mass spectrometry (SIMS) and speciation of dissolved C–O–H volatiles in silicate glasses was studied using Raman spectroscopy. Carbon contents of metallic melts were determined using both electron microprobe and SIMS. Our experiments indicate that at core-forming, reduced conditions, carbon in deep mafic–ultramafic magmas may dissolve primarily as various hydrogenated species but the total carbon storage capacity, although is significantly higher than solubility of CO2 under similar conditions, remains low (<500ppm). The total carbon content in our reduced melts at graphite saturation increases with increasing melt depolymerization (NBO/T), consistent with recent spectroscopic studies, and modestly with increasing hydration. Carbon behaves as a metal-loving element during core-mantle separation and our experimental DCmetal/silicate varies between ∼4750 and ⩾150 and increases with increasing pressure and decreases with increasing temperature and melt NBO/T.
Our data suggest that if only a trace amount of carbon (∼730ppm C) was available during early Earth differentiation, most of it was partitioned to the core (with 0.20–0.25wt.% C) and no more than ∼10–30% of the present-day mantle carbon budget (50–200ppm CO2) could be derived from a magma ocean residual to core formation. With equilibrium core formation removing most of the carbon initially retained in the terrestrial magma ocean, explanation of the modern bulk silicate Earth carbon inventory requires a later replenishment mechanism. Partial entrapment of metal melt in solid silicate matrix, carbon ingassing by magma ocean–atmosphere interaction, and carbon outgassing from the core aided by reaction of core metal and deeply subducted water are some of the viable mechanisms.
The composition and evolution of a metallic planetary core is determined by the behavior with pressure of the eutectic and the liquidus on the Fe-rich side of the Fe–FeS eutectic. New experiments at ...6GPa presented here, along with existing experimental data, inform a thermodynamic model for this liquidus from 1bar to at least 10GPa. Fe–FeS has a eutectic that becomes more Fe-rich but remains constant in T up to 6GPa. The 1bar, 3GPa, and 6GPa liquidi all cross at a pivot point at 1640±5K and FeS₃₇±₀.₅. This liquid/crystalline metal equilibrium is T–x-fixed and pressure independent through 6GPa. Models of the 1bar through 10GPa experimental liquidi show that with increasing P there is an increase in the T separation between the liquidus and the crest of the metastable two-liquid solvus. The solvus crest decreases in T with increasing P. The model accurately reproduces all the experimental liquidi from 1bar to 10GPa, as well as reproducing the 0–6GPa pivot point. The 14GPa experimental liquidus (Chen et al., 2008a,b) deviates sharply from the lower pressure trends indicating that the 0–10GPa model no longer applies to this 14GPa data.
Nanoparticles (NPs) are widely used in many industrial applications. NP fate and behavior in seawater are a very important issue for the assessment of their environmental impact and potential ...toxicity. In this study, the toxic effects of two nanomaterials, silicon dioxide (SiO
2
) and titanium dioxide (TiO
2
) NPs with similar primary size (~20 nm), on marine microalgae
Dunaliella tertiolecta
were investigated and compared. The dispersion behavior of SiO
2
and TiO
2
NPs in seawater matrix was investigated together with the relative trend of the exposed algal population growth. SiO
2
aggregates rapidly reached a constant size (600 nm) irrespective of the concentration while TiO
2
NP aggregates grew up to 4 ± 5 μm. The dose–response curve and population growth rate alteration of marine alga
D. tertiolecta
were evaluated showing that the algal population was clearly affected by the presence of TiO
2
NPs. These particles showed effects on 50 % of the population at 24.10 19.38–25.43 mg L
−1
(EC50) and a no observed effect concentration (NOEC) at 7.5 mg L
−1
. The 1 % effect concentration (EC1) value was nearly above the actual estimated environmental concentration in the aquatic environment. SiO
2
NPs were less toxic than TiO
2
for
D. tertiolecta
, with EC50 and NOEC values one order of magnitude higher. The overall toxic action seemed due to the contact between aggregates and cell surfaces, but while for SiO
2
a direct action upon membrane integrity could be observed after the third day of exposure, TiO
2
seemed to exert its toxic action in the first hours of exposure, mostly via cell entrapment and agglomeration.
Background
The Wechsler Intelligence Scale for Children – Fourth Edition often produces floor effects in individuals with intellectual disability. Calculating respondents' Z or age‐equivalent scores ...has been claimed to remedy this problem.
Method
The present study applied these methods to the Wechsler Intelligence Scale for Children – Fourth Edition scores of 198 individuals diagnosed with intellectual disability. Confirmatory factor analysis and profile analysis were conducted using a Bayesian approach.
Results
The intelligence structure in intellectual disability resembled the one previously reported for typical development, suggesting configural but not metric invariance. When Z or age‐equivalent scores (but not traditional scaled scores) were used, the average profile resembled the one previously reported for other neurodevelopmental disorders.
Conclusions
Both methods avoided any floor effects, generating similar but not identical profiles. Despite some practical and conceptual limitations, age‐equivalent scores may be easier to interpret. This was true even for a subgroup of individuals with more severe disabilities (mean IQ < 43).
The classification of mental, behavioural and neurodevelopmental disorders in the World Health Organization's International Classification of Diseases 11th revision (ICD-11) includes a comprehensive ...set of behavioural indicators (BIs) within the neurodevelopmental disorders grouping. BIs can be used to assess the severity of disorders of intellectual development in situations in which standardised measures of intellectual functioning and adaptive behaviours are not available or feasible. This international study examines the implementation characteristics of the BIs and compares them to standardised measures for assessing the severity of intellectual impairment and adaptive behaviours in disorders of intellectual development and autism spectrum disorder (ASD). The clinical utility of the ICD-11 and the fidelity of its application in international clinical settings were also assessed.
A total of 116 children and adolescents (5-18 years old) with a suspected or established diagnosis of disorders of intellectual development were included across four sites Italy (n = 18), Sri Lanka (n = 19) and two sites in India (n = 79). A principal component analysis was conducted to evaluate the application of the ICD-11 guidance for combining severity levels.
Assessment using the BIs showed a higher proportion of individuals classified with mild severity, whereas the standardised measures indicated a higher proportion of severe ratings. Additionally, individuals with co-occurring ASD tended to have more severe impairments compared with those without ASD, as indicated by both BIs and standardised measures. Overall, the BIs were considered clinically useful, although more time and consideration were required when applying the guidelines for individuals with a co-occurring disorder of intellectual development and ASD. The principal component analysis revealed one principal component representing overall disorders of intellectual development severity levels.
The ICD-11 BIs can be implemented as intended in international clinical settings for a broad range of presentations of individuals with neurodevelopmental disorders. Use of the BIs results in similar severity diagnoses to those made using standardised measures. The BIs are expected to improve the reliability of severity assessments in settings where appropriate standardised measures for intellectual and adaptive behaviours are not available or feasible.
The study aimed to prospectively assess incidence and risk factors for colistin-associated nephrotoxicity. This is a secondary analysis of a multicentre, randomized clinical trial, comparing efficacy ...and safety of colistin versus the combination of colistin plus rifampicin in severe infections due to extensively drug-resistant (XDR) Acinetobacter baumannii. The primary end point was acute kidney injury (AKI) during colistin treatment, assessed using the AKI Network Criteria, and considering death as a competing risk. A total of 166 adult patients without baseline kidney disease on renal replacement therapy were studied. All had life-threatening infections due to colistin-susceptible XDR A. baumannii. Patients received colistin intravenously at the same initial dose (2 million international units (MIU) every 8 h) with predefined dose adjustments according to the actual renal function. Serum creatinine was measured at baseline and at days 4, 7, 11, 14 and 21 (or last day of therapy when discontinued earlier). Outcomes assessed were ‘time to any kidney injury’ (AKI stages 1–3) and ‘time to severe kidney injury’ (considering only AKI stages 2–3 as events). When evaluating overall mortality, AKI occurrence was modelled as a time-dependent variable. AKI was observed in 84 patients (50.6%, stage 1 in 40.4%), with an incidence rate of 5/100 person-days (95% CI 4–6.2). Risk estimates of AKI at 7 and 14 days were 30.6% and 58.8%. Age and previous chronic kidney disease were significantly associated with any AKI in multivariable analysis. Neither ‘any’ nor ‘severe AKI’ were associated with on-treatment mortality (p 0.32 and p 0.54, respectively). AKI occurs in one-third to one-half of colistin-treated patients and is more likely in elderly patients and in patients with kidney disease. As no impact of colistin-associated AKI on mortality was found, this adverse event should not represent a reason for withholding colistin therapy, whenever indicated.
Background
Students with intellectual disabilities (IDs) have various learning difficulties and are at risk for school failure. Large inter‐individual differences are described for reading, but it is ...unclear how these vary as a function of grade. The aim of this study was to examine various reading fluency, accuracy and comprehension parameters in second‐to‐eighth‐grade Italian children with either borderline intellectual functioning (BIF) or mild ID (MID).
Methods
We examined 106 children with BIF (67 M and 39 F) and 168 children with MID (107 M and 61 F). The children were in the second to eighth grade and were comparable for chronological age (7 to 14 years). They were administered a battery of tests that assessed fluency and accuracy of word, pseudo‐word and text reading, as well as text comprehension. Standardised scores allowed us to compare the performance of the two groups with normative values.
Results
Children with ID obtained generally low scores compared with normative values. Those with MID had greater difficulty than those with BIF. Furthermore, difficulty was greater for speed than for accuracy measures and for words than for pseudo‐words. Difficulty (particularly in the case of reading speed) tended to be pronounced at later grades. Marked individual differences were present independently of MID–BIF subgrouping, as well as stimulus category and reading parameter.
Conclusions
As a group, children with ID showed difficulty in reading acquisition; the effect was greater for children with more severe ID, but large individual differences were observed in children with both BIF and MID. Relatively spared pseudo‐word reading skills indicate efficient use of the grapheme‐to‐phoneme conversion routine. This processing mode may prove more ineffective at higher levels of schooling when even in regular orthographies such as Italian typically developing children rely on lexical activation.
Background
The World Health Organization (WHO) has approved the 11th Revision of the International Classification of Diseases (ICD‐11). A version of the ICD‐11 for Mental, Behavioural and ...Neurodevelopmental Disorders for use in clinical settings, called the Clinical Descriptions and Diagnostic Requirements (CDDR), has also been developed. The CDDR includes behavioural indicators (BIs) for assessing the severity of disorders of intellectual development (DID) as part of the section on neurodevelopmental disorders. Reliable and valid diagnostic assessment measures are needed to improve identification and treatment of individuals with DID. Although appropriately normed, standardised intellectual and adaptive behaviour assessments are considered the optimal assessment approach in this area, they are unavailable in many parts of the world. This field study tested the BIs internationally to assess the inter‐rater reliability, concurrent validity, and clinical utility of the BIs for the assessment of DID.
Methods
This international study recruited a total of 206 children and adolescents (5–18 years old) with a suspected or established diagnosis of DID from four sites across three countries Sri‐Lanka (n = 57), Italy (n = 60) and two sites in India (n = 89). Two clinicians assessed each participant using the BIs with one conducting the clinical interview and the other observing. Diagnostic formulations using the BIs and clinical utility ratings were collected and entered independently after each assessment. At a follow‐up appointment, standardised measures (Leiter‐3, Vineland Adaptive Behaviour Scales‐II) were used to assess intellectual and adaptive abilities.
Results
The BIs had excellent inter‐rater reliability (intra‐class correlations ranging from 0.91 to 0.97) and good to excellent concurrent validity (intra‐class correlations ranging from 0.66 to 0.82) across sites. Compared to standardised measures, the BIs had more diagnostic overlap between intellectual and adaptive functioning. The BIs were rated as quick and easy to use and applicable across severities; clear and understandable with adequate to too much level of detail and specificity to describe DID; and useful for treatment selection, prognosis assessments, communication with other health care professionals, and education efforts.
Conclusion
The inclusion of newly developed BIs within the CDDR for ICD‐11 Neurodevelopmental Disorders must be supported by information on their reliability, validity, and clinical utility prior to their widespread adoption for international use. BIs were found to have excellent inter‐rater reliability, good to excellent concurrent validity, and good clinical utility. This supports use of the BIs within the ICD‐11 CDDR to assist with the accurate identification of individuals with DID, particularly in settings where specialised services are unavailable.
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