3,493 research outputs found

    Comment on "The global tree restoration potential"

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    Bastin et al. (Reports, 5 July 2019, p. 76) state that the restoration potential of new forests globally is 205 gigatonnes of carbon, conclude that “global tree restoration is our most effective climate change solution to date,” and state that climate change will drive the loss of 450 million hectares of existing tropical forest by 2050. Here we show that these three statements are incorrect

    Post-immunization leucocytosis and its implications for the management of febrile infants.

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    AIMS: Clinical guidelines for management of infants with fever but no evident focus of infection recommend that those aged 1-3 months with a white cell count >15 × 109/l have a full septic screen and be admitted for parenteral antibiotics. However, there is limited information about leucocyte changes following routine immunization, a common cause of fever. We investigated white cell counts shortly after routine immunization in Ugandan infants under 3 months of age. METHODS: White cell counts were measured in 212 healthy infants following routine immunizations (DTwP-HepB-Hib, oral polio and pneumococcal conjugate 7 vaccines) received prior to 3 months of age. RESULTS: Mean leucocyte counts increased from 9.03 × 109/l (95% confidence interval 8.59-9.47 × 109/l) pre-immunizations to 16.46 × 109/l (15.4-17.52 × 109/l) at one-day post-immunizations at 6 weeks of age, and 15.21 × 109/l (14.07-16.36 × 109/l) at one-day post-immunizations at 10 weeks of age. The leucocytosis was primarily a neutrophilia, with neutrophil percentages one-day post-immunization of 49% at 6 weeks of age and 46% at 10 weeks of age. White cell parameters returned to baseline by two-days post-immunization. No participant received antibiotics when presenting with isolated fever post-immunization and all remained well at follow-up. CONCLUSIONS: In our study almost half the children <3 months old presenting with fever but no evident focus of infection at one-day post-immunization met commonly used criteria for full septic screen and admission for parenteral antibiotics, despite having no serious bacterial infection. These findings add to the growing body of literature that questions the utility of white blood cell measurement in identification of young infants at risk of serious bacterial infections, particularly in the context of recent immunizations, and suggest that further exploration of the effect of different immunization regimes on white cell counts is needed. This observational work was nested within a clinical trial, registration number ISRCTN59683017

    Concurrent and distinct transcription and translation of transforming growth factor-beta type I and type II receptors in rodent embryogenesis

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    The transforming growth factor-betas (TGF-betas) are multifunctional regulatory polypeptides that play a crucial role in many cell processes and function through a set of cell surface protein receptors that includes TGF-beta type I (RI) and type II (RII). The present study reports a comprehensive comparison of the patterns of expression of TGF-beta RI and RII proteins and mRNAs in the developing mouse embryo using immunohistochemical and in situ hybridization analyses. Although widespread expression of both TGF-beta receptors was detected throughout the embryonic development period so that many similarities occur in localization of the TGF-beta receptors, TGF-beta RI was expressed in a well-defined, non-uniform pattern that was different in many respects from that of TGF-beta RII. Whereas higher levels of TGF-beta RI compared to TGF-beta RII were detected in some tissues of the embryo at the beginning of organogenesis, the level of TGF-beta RII increased more dramatically than that of TGF-beta RI during late organogenesis; this was especially true in many neural structures where TGF-beta RI and RII were comparable by day 16. The lung, kidney and intestine, in which epithelial-mesenchymal interactions occur, showed a complex pattern of TGF-beta RI and Rll expression. Additionally, northern blot hybridization and reverse transcription-polymerase chain reaction (RT-PCR) amplification showed non-uniform expression of the transcripts for TGF-beta RI and RII in embryonic and adult mouse and rat tissues. These data show that regulation of TGF-beta1 RI and RII occurs concurrently, but distinctly, in a spatial and temporal manner in rodent embryogenesis which may allow control of signal transduction of TGF-beta during development

    Dynamic monitoring of the shelf life of Cobia (Rachycentron canadum): a study on the applicability of a smart photochromic indicator.

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    To ensure the marketing of fresh fish-based products, it is necessary to develop fast methods that assess its freshness in real time. This study therefore evaluated the applicability of a photochromic time?temperature indicator (TTI) to monitor the time and temperature history during the period of validity of the whole fish of the cobia specimen stored in ice. The TTI response was both visibly interpreted as well as adaptable to measurement using suitable equipment. The results showed that the smart indicator activated during 6 s of ultraviolet light showed a similar rate of deterioration of the analysed product visual response, proving to be a dynamic shelf life indicator that can assure consumers the ultimate quality point of the entire cobia easily, cheaply and accurately

    Anemia Offers Stronger Protection Than Sickle Cell Trait Against the Erythrocytic Stage of Falciparum Malaria and This Protection Is Reversed by Iron Supplementation.

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    BACKGROUND: Iron deficiency causes long-term adverse consequences for children and is the most common nutritional deficiency worldwide. Observational studies suggest that iron deficiency anemia protects against Plasmodium falciparum malaria and several intervention trials have indicated that iron supplementation increases malaria risk through unknown mechanism(s). This poses a major challenge for health policy. We investigated how anemia inhibits blood stage malaria infection and how iron supplementation abrogates this protection. METHODS: This observational cohort study occurred in a malaria-endemic region where sickle-cell trait is also common. We studied fresh RBCs from anemic children (135 children; age 6-24months; hemoglobin <11g/dl) participating in an iron supplementation trial (ISRCTN registry, number ISRCTN07210906) in which they received iron (12mg/day) as part of a micronutrient powder for 84days. Children donated RBCs at baseline, Day 49, and Day 84 for use in flow cytometry-based in vitro growth and invasion assays with P. falciparum laboratory and field strains. In vitro parasite growth in subject RBCs was the primary endpoint. FINDINGS: Anemia substantially reduced the invasion and growth of both laboratory and field strains of P. falciparum in vitro (~10% growth reduction per standard deviation shift in hemoglobin). The population level impact against erythrocytic stage malaria was 15.9% from anemia compared to 3.5% for sickle-cell trait. Parasite growth was 2.4 fold higher after 49days of iron supplementation relative to baseline (p<0.001), paralleling increases in erythropoiesis. INTERPRETATION: These results confirm and quantify a plausible mechanism by which anemia protects African children against falciparum malaria, an effect that is substantially greater than the protection offered by sickle-cell trait. Iron supplementation completely reversed the observed protection and hence should be accompanied by malaria prophylaxis. Lower hemoglobin levels typically seen in populations of African descent may reflect past genetic selection by malaria. FUNDING: National Institute of Child Health and Development, Bill and Melinda Gates Foundation, UK Medical Research Council (MRC) and Department for International Development (DFID) under the MRC/DFID Concordat

    Light curves of hydrogen-poor Superluminous Supernovae from the Palomar Transient Factory

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    We investigate the light-curve properties of a sample of 26 spectroscopically confirmed hydrogen-poor superluminous supernovae (SLSNe-I) in the Palomar Transient Factory (PTF) survey. These events are brighter than SNe Ib/c and SNe Ic-BL, on average, by about 4 and 2~mag, respectively. The peak absolute magnitudes of SLSNe-I in rest-frame gg band span 22Mg20-22\lesssim M_g \lesssim-20~mag, and these peaks are not powered by radioactive 56^{56}Ni, unless strong asymmetries are at play. The rise timescales are longer for SLSNe than for normal SNe Ib/c, by roughly 10 days, for events with similar decay times. Thus, SLSNe-I can be considered as a separate population based on photometric properties. After peak, SLSNe-I decay with a wide range of slopes, with no obvious gap between rapidly declining and slowly declining events. The latter events show more irregularities (bumps) in the light curves at all times. At late times, the SLSN-I light curves slow down and cluster around the 56^{56}Co radioactive decay rate. Powering the late-time light curves with radioactive decay would require between 1 and 10M{\rm M}_\odot of Ni masses. Alternatively, a simple magnetar model can reasonably fit the majority of SLSNe-I light curves, with four exceptions, and can mimic the radioactive decay of 56^{56}Co, up to 400\sim400 days from explosion. The resulting spin values do not correlate with the host-galaxy metallicities. Finally, the analysis of our sample cannot strengthen the case for using SLSNe-I for cosmology.Comment: 120 pages, 48 figures, 78 tables. ApJ in pres

    Iron for Africa-Report of an Expert Workshop.

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    Scientific experts from nine countries gathered to share their views and experience around iron interventions in Africa. Inappropriate eating habits, infections and parasitism are responsible for significant prevalence of iron deficiency, but reliable and country-comparable prevalence estimates are lacking: improvements in biomarkers and cut-offs values adapted to context of use are needed. Benefits of iron interventions on growth and development are indisputable and outweigh risks, which exist in populations with a high infectious burden. Indeed, pathogen growth may increase with enhanced available iron, calling for caution and preventive measures where malaria or other infections are prevalent. Most African countries programmatically fortify flour and supplement pregnant women, while iron deficiency in young children is rather addressed at individual level. Coverage and efficacy could improve through increased access for target populations, raised awareness and lower cost. More bioavailable iron forms, helping to decrease iron dose, or prebiotics, which both may lower risk of infections are attractive opportunities for Africa. Fortifying specific food products could be a relevant route, adapted to local context and needs of population groups while providing education and training. More globally, partnerships involving various stakeholders are encouraged, that could tackle all aspects of the issue

    Thermodynamic modelling of BFS-PC cements under temperature conditions relevant to the geological disposal of nuclear wastes

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    Intermediate level waste produced in UK nuclear power generation is encapsulated or immobilised in blended cements comprising blast furnace slag (BFS) and Portland cement (PC), to be emplaced in a proposed geological disposal facility (GDF). The wasteforms are expected to be exposed to temperatures from 35 to 80 °C during the initial 150 years of GDF operation. Thermodynamic modelling is applied here to describe the phase assemblages of hydrated 1:1, 3:1 and 9:1 BFS-PC blends, with the participation of hydrogarnet as an important phase above 60 °C. The chemical composition of the main phase forming in these systems, an aluminium rich calcium silicate hydrate (C-A-S-H), was well described by a solid-solution model with explicit Al incorporation, although the Al/Si ratio was systematically slightly under-predicted. The developed thermodynamic model predicts the correct phase assemblage across varying temperature regimes, making it a valuable tool to assess the effects of temperature on cements
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