275 research outputs found

    Drivers and uncertainties of future global marine primary production in marine ecosystem models

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    Past model studies have projected a global decrease in marine net primary production (NPP) over the 21st century, but these studies focused on the multi-model mean rather than on the large inter-model differences. Here, we analyze model-simulated changes in NPP for the 21st century under IPCC's high-emission scenario RCP8.5. We use a suite of nine coupled carbon–climate Earth system models with embedded marine ecosystem models and focus on the spread between the different models and the underlying reasons. Globally, NPP decreases in five out of the nine models over the course of the 21st century, while three show no significant trend and one even simulates an increase. The largest model spread occurs in the low latitudes (between 30° S and 30° N), with individual models simulating relative changes between −25 and +40 %. Of the seven models diagnosing a net decrease in NPP in the low latitudes, only three simulate this to be a consequence of the classical interpretation, i.e., a stronger nutrient limitation due to increased stratification leading to reduced phytoplankton growth. In the other four, warming-induced increases in phytoplankton growth outbalance the stronger nutrient limitation. However, temperature-driven increases in grazing and other loss processes cause a net decrease in phytoplankton biomass and reduce NPP despite higher growth rates. One model projects a strong increase in NPP in the low latitudes, caused by an intensification of the microbial loop, while NPP in the remaining model changes by less than 0.5 %. While models consistently project increases NPP in the Southern Ocean, the regional inter-model range is also very substantial. In most models, this increase in NPP is driven by temperature, but it is also modulated by changes in light, macronutrients and iron as well as grazing. Overall, current projections of future changes in global marine NPP are subject to large uncertainties and necessitate a dedicated and sustained effort to improve the models and the concepts and data that guide their developmen

    Corrigendum: Short-lived positron emitters in beam-on PET imaging during proton therapy (2015 Phys. Med. Biol. 60 8923)

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    Because of strong indications of multiple counting by the multi-channel scaler (MCS) during most of the experiments described in Dendooven et al (2015 Phys. Med. Biol. 60 8923–47), the production of short-lived positron emitters in the stopping of 55 MeV protons in water, carbon, phosphorus and calcium was remeasured. The new results are reported here. With proper single counting of the MCS, the new production rates are 1.1 to 2.9 times smaller than reported in Dendooven et al (2015 Phys. Med. Biol. 60 8923–47). The omission of the conversion from MCS time bin to time unit in the previous data analysis was corrected, leading to an increase of the production rate by a factor of 2.5 or 10 for some nuclides. The most copiously produced short-lived nuclides and their production rates relative to the relevant long-lived nuclides are: 12N (T 1/2  =  11 ms) on carbon (5.3% of 11C), 29P (T 1/2  =  4.1 s) on phosphorus (23% of 30P) and 38mK (T 1/2  =  0.92 s) on calcium (173% of 38gK). The number of decays integrated from the start of an irradiation as a function of time during the irradiation of PMMA and 4 tissue materials has been determined. For (carbon-rich) adipose tissue, 12N dominates up to 70 s. On bone tissue, 38mK dominates the beam-on PET counts from 0.2–0.7 s until about 80–110 s. Considering nuclides created on phosphorus and calcium, the short-lived ones provide 8 times more decays than the long-lived ones during a 70 s irradiation. Bone tissue will thus be much better visible in beam-on PET compared to PET imaging after an irradiation. From the estimated number of 12N PET counts, we conclude that, for any tissue, except carbon-poor ones, 12N PET imaging potentially provides equal quality proton range information as prompt gamma imaging with an optimized knife-edge slit camera

    Evaluating Oceanic Uptake of Atmospheric CCl4: A Combined Analysis of Model Simulations and Observations

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    We provide new estimates of the air‐sea flux of CCl4 using simulations from a global ocean biogeochemistry model (NEMO‐PlankTOM) in combination with depth‐resolved CCl4 observations from global oceanic databases. Estimates of global oceanic CCl4 uptake are derived from a range of model analyses, including prescribed parameterizations using reported values on hydrolysis and degradation, and analyses optimized using the global observational databases. We evaluate the sensitivity of our results to uncertainties in air‐sea gas exchange parameterization, estimation period, and circulation processes. Our best constrained estimate of ocean CCl4 uptake for the period 1996–2000 is 20.1 Gg/year (range 16.6–22.7), corresponding to estimates of the partial atmospheric lifetime with respect to ocean uptake of 124 (110–150) years. This new oceanic lifetime implies higher emissions of CCl4 than currently estimated and therefore a larger missing atmospheric source of CCl4

    What range of motion is achieved 5 years after external rotationplasty of the shoulder in infants with an obstetric brachial plexus injury?

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    Background Obstetric brachial plexus injuries result from traction injuries during delivery, and 30% of these children have persisting functional limitations related to an external rotation deficit of the shoulder. Little is known about the long-term effect of soft-tissue procedures of the shoulder in patients with obstetric brachial plexus injuries. Questions/purposes (1) After soft-tissue release for patients with passive external rotation less than 20 degrees and age younger than 2 years and for patients older than 2 years with good external rotation strength, what are the improvements in passive external rotation and abduction arcs at 1 and 5 years? (2) For patients who underwent staged tendon transfer after soft-tissue release, what are the improvements in active external rotation and abduction arcs at 1 and 5 years? (3) For patients with passive external rotation less than 20 degrees and no active external rotation, what are the improvements in active external rotation and abduction arcs at 1 and 5 years? Methods This was a retrospective analysis of a longitudinally maintained institutional database. Between 1996 and 2009, 149 children underwent a soft-tissue procedure of the shoulder for an internal rotation contracture. The inclusion criteria were treatment with an internal contracture release and/or tendon transfer, a maximum age of 18 years at the time of surgery, and a minimum follow-up period of 2 years. Six patients were older than 18 years at the time of surgery and 31 children were seen at our clinic until 1 year postoperatively, but because they had good clinical results and lived far away from our center, these children were discharged to physical therapists in their hometown for annual follow-up. Thus, 112 children (59 boys) were available for analysis. Patients with passive external rotation less than 20 degrees and age younger than 2 years and patients older than 2 years with good external rotation strength received soft-tissue release only (n = 37). Of these patients, 17 children did not have adequate active external rotation, and second-stage tendon transfer surgery was performed. For patients with passive external rotation less than 20 degrees with no active external rotation, single-stage contracture release with tendon transfer was performed (n = 68). When no contracture was present (greater than 20 degrees of external rotation) but the patient had an active deficit (n = 7), tendon transfer alone was performed; this group was not analyzed. A functional assessment of the shoulder was performed preoperatively and postoperatively at 6 weeks, 3 months, and annually thereafter and included abduction, external rotation in adduction and abduction, and the Mallet scale. Results Internal contracture release resulted in an improvement in passive external rotation in adduction and abduction of 29 degrees (95% confidence interval, 21 to 38; p < 0.001) and 17 degrees (95% CI, 10 to 24; p < 0.001) at 1 year of follow-up and 25 degrees (95% CI, 15-35; p < 0.001) and 15 degrees (95% CI, 7 to 24; p = 0.001) at 5 years. Because of insufficient strength of the external rotators after release, 46% of the children (17 of 37) underwent an additional tendon transfer for active external rotation, resulting in an improvement in active external rotation in adduction and abduction at each successive follow-up visit. Patients with staged transfers had improved active function; improvements in active external rotation in adduction and abduction were 49 degrees (95% CI, 28 to 69; p < 0.05) and 45 degrees (95% CI, 11 to 79; p < 0.001) at 1 year of follow-up and 38 degrees (95% CI, 19 to 58; p < 0.05) and 23 degrees (95% CI, -8 to 55; p < 0.001) at 5 years. In patients starting with less than 20 degrees of passive external rotation and no active external rotation, after single-stage contracture release and tendon transfer, active ROM was improved. Active external rotation in adduction and abduction were 75 degrees (95% CI, 66 to 84; p < 0.001) and 50 degrees (95% CI, 43 to 57; p < 0.001) at 1 year of follow-up and 65 degrees (95% CI, 50 to 79; p < 0.001) and 40 degrees (95% CI, 28 to 52; p < 0.001) at 5 years. Conclusion Young children with obstetric brachial plexus injuries who have internal rotation contractures may benefit from soft-tissue release. When active external rotation is lacking, soft-tissue release combined with tendon transfer improved active external rotation in this small series. Future studies on the degree of glenohumeral deformities and functional outcome might give more insight into the level of increase in external rotation.Development and application of statistical models for medical scientific researc

    Reading, Trauma and Literary Caregiving 1914-1918: Helen Mary Gaskell and the War Library

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    This article is about the relationship between reading, trauma and responsive literary caregiving in Britain during the First World War. Its analysis of two little-known documents describing the history of the War Library, begun by Helen Mary Gaskell in 1914, exposes a gap in the scholarship of war-time reading; generates a new narrative of "how," "when," and "why" books went to war; and foregrounds gender in its analysis of the historiography. The Library of Congress's T. W. Koch discovered Gaskell's ground-breaking work in 1917 and reported its successes to the American Library Association. The British Times also covered Gaskell's library, yet researchers working on reading during the war have routinely neglected her distinct model and method, skewing the research base on war-time reading and its association with trauma and caregiving. In the article's second half, a literary case study of a popular war novel demonstrates the extent of the "bitter cry for books." The success of Gaskell's intervention is examined alongside H. G. Wells's representation of textual healing. Reading is shown to offer sick, traumatized and recovering combatants emotional and psychological caregiving in ways that she could not always have predicted and that are not visible in the literary/historical record

    Methods for interpreting lists of affected genes obstained in a DNA microarray experiment

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    Background - The aim of this paper was to describe and compare the methods used and the results obtained by the participants in a joint EADGENE (European Animal Disease Genomic Network of Excellence) and SABRE (Cutting Edge Genomics for Sustainable Animal Breeding) workshop focusing on post analysis of microarray data. The participating groups were provided with identical lists of microarray probes, including test statistics for three different contrasts, and the normalised log-ratios for each array, to be used as the starting point for interpreting the affected probes. The data originated from a microarray experiment conducted to study the host reactions in broilers occurring shortly after a secondary challenge with either a homologous or heterologous species of Eimeria. Results - Several conceptually different analytical approaches, using both commercial and public available software, were applied by the participating groups. The following tools were used: Ingenuity Pathway Analysis, MAPPFinder, LIMMA, GOstats, GOEAST, GOTM, Globaltest, TopGO, ArrayUnlock, Pathway Studio, GIST and AnnotationDbi. The main focus of the approaches was to utilise the relation between probes/genes and their gene ontology and pathways to interpret the affected probes/genes. The lack of a well-annotated chicken genome did though limit the possibilities to fully explore the tools. The main results from these analyses showed that the biological interpretation is highly dependent on the statistical method used but that some common biological conclusions could be reached. Conclusion - It is highly recommended to test different analytical methods on the same data set and compare the results to obtain a reliable biological interpretation of the affected genes in a DNA microarray experimen

    Ancient DNA shows domestic horses were introduced in the southern caucasus and anatolia during the bronze age

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    Despite the important roles that horses have played in human history, particularly in the spread of languages and cultures, and correspondingly intensive research on this topic, the origin of domestic horses remains elusive. Several domestication centers have been hypothesized, but most of these have been invalidated through recent paleogenetic studies. Anatolia is a region with an extended history of horse exploitation that has been considered a candidate for the origins of domestic horses but has never been subject to detailed investigation. Our paleogenetic study of pre- and protohistoric horses in Anatolia and the Caucasus, based on a diachronic sample from the early Neolithic to the Iron Age (~8000 to ~1000 BCE) that encompasses the presumed transition from wild to domestic horses (4000 to 3000 BCE), shows the rapid and large-scale introduction of domestic horses at the end of the third millennium BCE. Thus, our results argue strongly against autochthonous independent domestication of horses in Anatolia

    Aberrant Expression of ID2 protein and its correlation with EBV-LMP1 and P16(INK4A) in Classical Hodgkin Lymphoma in China

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    <p>Abstract</p> <p>Background</p> <p>The relationships between the expression of ID2, EBV-LMP1 and P16(INK4A) in Chinese classical Hodgkin lymphoma are unknown and need exploring.</p> <p>Methods</p> <p>Samples of classical Hodgkin lymphoma from 60 Chinese patients were analyzed for the expression of ID2, EBV-LMP1 and p16(INK4A) proteins by immunohistochemistry.</p> <p>Results</p> <p>ID2 protein was expressed in 83.3% of this group of classical Hodgkin lymphoma, staining strongly in both cytoplasm and nucleus of the Hodgkin and Reed-Sternberg (HRS) cells. EBV-LMP1 and P16(INK4A) were overexpressed in 85.0% and 71.7% of Hodgkin lymphoma, respectively. EBV-LMP1 was noted in the cytoplasm, membrane and nucleus of HRS cells; P16(INK4A) was in the nucleus and cytoplasm. Microscopically, ID2, EBV-LMP1 and P16(INK4A) staining distinguished the HRS cells from the complex background of lymphocytes. ID2 was positively correlated with EBV-LMP1(<it>P </it>< 0.01), but P16(INK4A) was inversely related to EBV-LMP1 (<it>P </it>< 0.05).</p> <p>Conclusion</p> <p>It is suggested that ID2, EBV-LMP1 and P16(INK4A) could play an important role in the evolution of classical Hodgkin lymphoma, and be considered as potential adjunct markers to identify HRS cells in diagnosis.</p
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