Hillslopes record the growth and decay of landscapes

Earth's surface archives the combined history of tectonics and erosion, which tend to roughen landscapes, and sediment transport and deposition, which smooth them. We analyzed hillslope morphology in the tectonically active Dragon’s Back Pressure Ridge in California, United States, to assess whether tectonic uplift history can be reconstructed using measurable attributes of hillslope features within landscapes. Hilltop curvature and hillslope relief mirror measured rates of vertical displacement caused by tectonic forcing, and their relationships are consistent with those expected when idealizing hillslope transport as a nonlinear diffusion process. Hilltop curvature lags behind relief in its response to changing erosion rates, allowing growing landscapes to be distinguished from decaying landscapes. Numerical modeling demonstrates that hillslope morphology may be used to infer changes in tectonic rates

Global projection of lead-zinc supply from known resources

© 2018 by the authors. Lead and zinc are used extensively in the construction and automotive industries, and require sustainable supply. In order to understand the future availability of lead and zinc, we have projected global supplies on a country-by-country basis from a detailed global assessment of mineral resources for 2013. The model GeRS-DeMo was used to create projections of lead and zinc production from ores, as well as recycling for lead. Our modelling suggests that lead and zinc production from known resources is set to peak within 15 years (lead 2025, zinc 2031). For lead, the total supply declines relatively slowly post peak due to recycling. If additional resources are found, these peaks would shift further into the future. These results suggest that lead and zinc consumers will need to plan for the future, potentially by: seeking alternative supplies (e.g., mine tailings, smelter/refinery slags); obtaining additional value from critical metals contained in lead-zinc ore deposits to counter lower grade ores; identifying potential substitutes; redesigning their products; or by contributing to the development of recycling industries

Hypermethioninaemia due to methionine adenosyltransferase I/III (MAT I/III) deficiency: diagnosis in an expanded neonatal screening programme

The Expanded Newborn Screening Program (MS/MS) in the region of Galicia (NW Spain) was initiated in 2000 and includes the measurement of methionine levels in dried blood spots. Between June 2000 and June 2007, 140 818 newborns were analysed, and six cases of persistent hypermethioninaemia were detected: one homocystinuria due to cystathionine β-synthase (CβS) deficiency, and five methionine adenosyltransferase I/III (MAT I/III) deficiencies. The five cases of MAT I/III deficiency represent an incidence of 1/28 163 newborns. In these five patients, methionine levels in dried blood spots ranged from 50 to 147 μmol/L. At confirmation of the persistence of the hypermethioninaemia in a subsequent plasma sample, plasma methionine concentrations were moderately elevated in 4 of the 5 patients (mean 256 μmol/L), while total homocysteine (tHcy) was normal; the remaining patient showed plasma methionine of 573 μmol/L and tHcy of 22.8 μmol/L. All five patients were heterozygous for the same dominant mutation, R264H in the MAT1A gene. With a diet not exceeding recommended protein requirements for their age, all patients maintained methionine levels below 300 μmol/L. Currently, with a mean of 2.5 years since diagnosis, the patients are asymptomatic and show developmental quotients within the normal range. Our results show a rather high frequency of hypermethioninaemia due to MAT I/III deficiency in the Galician neonatal population, indicating a need for further studies to evaluate the impact of persistent isolated hypermethioninaemia in neonatal screening programmes

Environmental influences on familial discordance of phenotype in people with homocystinuria: a case report

<p>Abstract</p> <p>Introduction</p> <p>Non-heritable factors may have an influence on the clinical expression of monogenic inherited metabolic diseases.</p> <p>Case presentation</p> <p>This is a case report of a man whose mother had been diagnosed late in childhood with pyridoxine responsive homocystinuria with lens dislocation and neurodevelopmental delay. These severe complications were not observed in her son who was pyridoxine unresponsive but who had been treated appropriately since early infancy.</p> <p>Conclusion</p> <p>The phenotype of people with homocystinuria can be discordant within a family, with variability in metabolic and clinical expression depending upon both the genotype and therapeutic interventions. Offspring of people with homocystinuria should be screened in early infancy and, if positive, treated appropriately whether they have pyridoxine responsive or unresponsive disease.</p

Location matters:Valuing firm-specific nonmarket risk in the global mining industry

Research summary Using collective action and social movement theory, we investigate the potential incentives and ability of stakeholders to engage in collective action that can increase firm-specific nonmarket risk of mining companies. We argue that proximity to the nearest environmentally sensitive water source increases the probability that local stakeholders will take collective actions that impose material costs on the focal mine. We hypothesize that stock markets recognize this nonmarket risk and apply a discount on announcements related to mines located near such areas, and that these risks are moderated by the type of mineral, the nature of the water source, and the strength of host country institutions. Using a unique data set and an event study method, we find support for most of our arguments. Managerial summary We argue that mines located near environmentally sensitive water sources are subject to nonmarket risks arising from the potential collective actions of local stakeholders and their allies. Stakeholder mobilization can impose material costs on a mine in the form of delays, regulatory hurdles, and closure. We find that stock markets recognize these nonmarket risks and apply a discount on announcements by mining companies whose mines are located near environmentally sensitive water sources, particularly rivers. However, we also find that investor reaction is stronger in countries with strong institutions that support collective action. Thus, nonmarket risk management is important even in countries that are typically characterized by low political and institutional risks. We discuss the degree to which these results can be generalized beyond mining

Quantum confined acceptors and donors in InSe nanosheets

We report on the radiative recombination of photo-excited carriers bound at native donors and acceptors in exfoliated nanoflakes of nominally undoped rhombohedral gamma-polytype InSe. The binding energies of these states are found to increase with the decrease in flake thickness, L. We model their dependence on L using a two-dimensional hydrogenic model for impurities and show that they are strongly sensitive to the position of the impurities within the nanolayer. (c) 2014 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License

Newborn Screening for Homocystinuria Revealed a High Frequency of MAT I/III Deficiency in Iberian Peninsula

Acessível em: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4375120/Homocystinuria due to cystathionine β-synthase deficiency or "classical homocystinuria" is a rare autosomal recessive condition resulting in altered sulfur metabolism with elevated methionine and homocysteine in plasma and homocystine in urine. This condition is characterized by a high clinical heterogeneity, which contributes to late clinical diagnosis, usually only made after irreversible damage has occurred. Treatment is effective if started before clinical symptoms. The analysis of methionine levels by tandem mass spectrometry (MS/MS) allows the newborn screening for homocystinuria, but false-positive results can be frequently obtained and lead to the unwanted identification of methionine adenosyl transferase (MAT I/III) deficiency. This latter condition is biochemically characterized by isolated persistent hypermethioninemia, accompanied in some individuals with slightly elevated levels of homocysteine in plasma. A dominant form of MAT I/III deficiency, associated with mutation p.R264H, seems to be very frequent in the Iberian Peninsula and usually has a clinically benign course. Both these metabolic disorders are screened in Galicia and Portugal since the introduction of the MS/MS technology, in 2000 and 2004, respectively, resulting in the identification of three patients with classical homocystinuria and 44 patients with MAT I/III deficiency. All but one heterozygous parent of MAT I/III patients, identified with the p.R264H mutation, are healthy adults around the age of 30/40. The implementation of a second-tier test for homocysteine in dried blood spots would considerably reduce the number of MAT I/III-deficient patients identified and improve the specificity and positive predictive value for classical homocystinuria screening