302 research outputs found
An Imaging Study of Working Memory: The Effects of Concurrent Articulation on Phonological Tasks and the Cerebellum's Role
Recent work has shown that cerebellar patients have difficulty with particular types of rhyme judgments (pairs with phonological and orthographic mismatch), as well as working memory tasks (Ben-Yehudah and Fiez, 2008). Both working memory and rhyme judgment tasks can be disrupted by concurrent articulation (Gathercole and Baddeley, 1994; Besner 1987), indicating a possible set of common regions in the cerebellum. In a review investigating the effects of concurrent articulation on phonological judgment tasks, Besner (1987) found differential effects for rhyme judgments compared to homophone and non-word homophone judgments. Interestingly, there may be differences even within rhyme judgments where word pairs with mixed phonological and orthographic (visual) similarity are more affected by concurrent articulation (Johnston and McDermott, 1986). We performed a behavioral experiment (Experiment 1) to replicate the effects found by both Besner and Johnston and McDermott. Our behavioral experiment found similar results. Concurrent articulation decreased the accuracy of rhyme judgments but not homophone and non-word homophone judgments; within the rhyme judgment task, word pairs with mixed phonology and orthography were the most affected. In order to elucidate the potential role of the cerebellum in these tasks, we designed a neuroimaging experiment (Experiment 2) with both a working memory component and a phonological tasks component. We identified a set of ten regions that were positively active during the working memory task and used this set of regions to explore potential regions of overlap between working memory and rhyme judgment, but not homophone and non-word homophone judgments. Of the ten regions active for the phonological tasks, only one bilateral region in the superior cerebellum showed a significant task effect. Counter to what we had hypothesized, it showed greater activation for the homophone and non-word homophone judgments than the rhyme judgments. While our results show a separation of the tasks in this bilateral region, further study is necessary to help explain why we saw lower activation for rhyming in this region and why we were unable to identify any rhyme specific areas within the cerebellum
Inositol 1,3,4,5,6-pentakisphosphate 2-kinase is a distant IPK member with a singular inositide binding site for axial 2-OH recognition
Inositol phosphates (InsPs) are signaling molecules with multiple roles in cells. In particular Graphic (InsP6) is involved in mRNA export and editing or chromatin remodeling among other events. InsP6 accumulates as mixed salts (phytate) in storage tissues of plants and plays a key role in their physiology. Human diets that are exclusively grain-based provide an excess of InsP6 that, through chelation of metal ions, may have a detrimental effect on human health. Ins(1,3,4,5,6)P5 2-kinase (InsP5 2-kinase or Ipk1) catalyses the synthesis of InsP6 from InsP5 and ATP, and is the only enzyme that transfers a phosphate group to the axial 2-OH of the myo-inositide. We present the first structure for an InsP5 2-kinase in complex with both substrates and products. This enzyme presents a singular structural region for inositide binding that encompasses almost half of the protein. The key residues in substrate binding are identified, with Asp368 being responsible for recognition of the axial 2-OH. This study sheds light on the unique molecular mechanism for the synthesis of the precursor of inositol pyrophosphates
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Impacts of elevated atmospheric CO₂ on nutrient content of important food crops.
One of the many ways that climate change may affect human health is by altering the nutrient content of food crops. However, previous attempts to study the effects of increased atmospheric CO2 on crop nutrition have been limited by small sample sizes and/or artificial growing conditions. Here we present data from a meta-analysis of the nutritional contents of the edible portions of 41 cultivars of six major crop species grown using free-air CO2 enrichment (FACE) technology to expose crops to ambient and elevated CO2 concentrations in otherwise normal field cultivation conditions. This data, collected across three continents, represents over ten times more data on the nutrient content of crops grown in FACE experiments than was previously available. We expect it to be deeply useful to future studies, such as efforts to understand the impacts of elevated atmospheric CO2 on crop macro- and micronutrient concentrations, or attempts to alleviate harmful effects of these changes for the billions of people who depend on these crops for essential nutrients
Quantitative trait loci conferring grain mineral nutrient concentrations in durum wheat 3 wild emmer wheat RIL population
Mineral nutrient malnutrition, and particularly
deficiency in zinc and iron, afflicts over 3 billion people
worldwide. Wild emmer wheat, Triticum turgidum ssp.
dicoccoides, genepool harbors a rich allelic repertoire for
mineral nutrients in the grain. The genetic and physiological
basis of grain protein, micronutrients (zinc, iron,
copper and manganese) and macronutrients (calcium,
magnesium, potassium, phosphorus and sulfur) concentration
was studied in tetraploid wheat population of 152
recombinant inbred lines (RILs), derived from a cross
between durum wheat (cv. Langdon) and wild emmer
(accession G18-16). Wide genetic variation was found
among the RILs for all grain minerals, with considerable
transgressive effect. A total of 82 QTLs were mapped for
10 minerals with LOD score range of 3.2–16.7. Most QTLs
were in favor of the wild allele (50 QTLs). Fourteen pairs
of QTLs for the same trait were mapped to seemingly
homoeologous positions, reflecting synteny between the A
and B genomes. Significant positive correlation was found
between grain protein concentration (GPC), Zn, Fe and Cu,
which was supported by significant overlap between the
respective QTLs, suggesting common physiological and/or
genetic factors controlling the concentrations of these
mineral nutrients. Few genomic regions (chromosomes 2A,
5A, 6B and 7A) were found to harbor clusters of QTLs for
GPC and other nutrients. These identified QTLs may
facilitate the use of wild alleles for improving grain
nutritional quality of elite wheat cultivars, especially in
terms of protein, Zn and Fe
Restricting digital sites of dissent: commercial social media and free expression
The widespread use of commercial social media platforms by protesters and activists has enhanced protest mobilisation and reporting but it has placed social media providers in the intermediary role as facilitators of dissent and has thereby created new challenges. Companies like Google and Facebook are increasingly restricting content that is published on or distributed through their platforms; they have been subject to obstruction by governments; and their services have been at the core of large-scale data collection and surveillance. This article analyses and categorises forms of infrastructure-based restrictions on free expression and dissent. It shows how private intermediaries have been incorporated into state-led content policies; how they set their own standards for legitimate online communication and intervene accordingly; and how state-based actions and commercial self-regulation intersect in the specific area of online surveillance. Based on a broad review of cases, it situates the role of social media in the wider trend of the privatisation of communications policy and the complex interplay between state-based regulation and commercial rule-making
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Standing on the shoulders of tech giants: Media delivery, streaming television, and the rise of global suppliers
This article uses the case study of Internet Protocol (IP) delivery for streaming television to demonstrate how technology and globalization combine to change what media firms do, how they create value, and with whom. Media delivery - the sum of the value-adding tasks necessary to transfer content from source to audience - has become a mosaic of technologies that sustain a complex and fast-evolving video ecosystem. Broadcasters had been in charge of the full transmission process once, of tasks deemed core to their business. Today, media delivery is externalized to the market and devolved to a network of suppliers. These suppliers are no ordinary firms, but tech giants that have developed deep global capabilities. They gain further leverage by being cross-sectoral, serving clients across multiple industries. Who are these suppliers? What makes them unique? And what are the implications for the television industry
Down-regulation of the myo-inositol oxygenase gene family has no effect on cell wall composition in Arabidopsis
The enzyme myo-inositol oxygenase (MIOX; E.C. 1.13.99.1) catalyzes the ring-opening four-electron oxidation of myo-inositol into glucuronic acid, which is subsequently activated to UDP-glucuronic acid (UDP-GlcA) and serves as a precursor for plant cell wall polysaccharides. Starting from single T-DNA insertion lines in different MIOX-genes a quadruple knockdown (miox1/2/4/5-mutant) was obtained by crossing, which exhibits greater than 90% down-regulation of all four functional MIOX genes. Miox1/2/4/5-mutant shows no visible phenotype and produces viable pollen. The alternative pathway to UDP-glucuronic acid via UDP-glucose is upregulated in the miox1/2/4/5-mutant as a compensatory mechanism. Miox1/2/4/5-mutant is impaired in the utilization of myo-inositol for seedling growth. The incorporation of myo-inositol derived sugars into cell walls is strongly (>90%) inhibited. Instead, myo-inositol and metabolites produced from myo-inositol such as galactinol accumulate in the miox1/2/4/5-mutant. The increase in galactinol and raffinose family oligosaccharides does not enhance stress tolerance. The ascorbic acid levels are the same in mutant and wild type plants
Approach to endoscopic extraperitoneal radical prostatectomy (EERPE): the impact of previous laparoscopic experience on the learning curve
BACKGROUND: We report our approach regarding the technique of endoscopic extraperitoneal radical prostatectomy (EERPE) and analyze the learning curve of two surgeons after thorough technical training under expert monitoring. The purpose of this study was to investigate the influence of expert monitoring on the surgical outcome and whether previous laparoscopic experience influences the surgeon's learning curve. METHODS: EERPE was performed on 120 consecutive patients by two surgeons with different experience in laparoscopy. An analysis and comparison of their learning curve was made. RESULTS: Median operation time: 200 (110-415) minutes. Complications: no conversion, blood transfusion (1.7%), rectal injury (3.3%). Median catheterisation time: 6 (5-45) days. Histopathological data: 55% pT2, 45% pT3 with a positive surgical margin rate of 6.1% and 46%, respectively. After 12 months, 78% of the patients were continent, 22% used 1 or more pad. Potency rate with or without PDE-5-inhibitors was 66% with bilateral and 31% with unilateral nerve-sparing, respectively. Operation time was the only parameter to differ significantly between the two surgeons. CONCLUSION: EERPE can be learned within a short teaching phase. Previous laparoscopic experience is reflected by shorter operation times, not by lower complication rates or superior early oncological data
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