241 research outputs found

    Exploring the Differences in Girls’ and Boys’ Learning from Their Teachers’ Perspectives in a Coed High School in Kingston, Jamaica

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    Girls’ and boys’ learning has been socially constructed through capitalism, which is replicated in patriarchy, and connoted with recognized physical learned behaviors that have been perpetuated in Jamaica’s culture throughout generations. Employing historical materialism and black feminist theories, this study assumes that the socio-economic and political structure of colonialism to present neocolonialism has been inherently biased towards men while negating women, and had instituted classifications that have characterized girls and boys as different. The perception that differences exist is described through an ethnographic micro case study analysis that examined grade 10 girls and boys at a specific coed high school in Kingston, Jamaica from May – August 2015. This served as a microcosm of Jamaica’s general society. Data were gathered using participant observation and semi-structured interviews with 22 teachers, 10 females, and 12 males in different subject disciplines and were analyzed through descriptive coding of major codes: expectation, interests and participation and sub-codes. The analysis explains that there are no differences in the ways that boys and girls learn. The notion that differences exist arose from the social structures embedded in the country’s history that have implicated the formal education system through set curricula in which teachers themselves were trained to accept and have internalized. The teachers’ accommodation and attitude toward the ways 10th-grade girls and boys learn result from how they were socialized. I adhere to the reality that girls experience difficulty in learning like boys, and with more struggles that often get dismissed and ignored

    Melting of a 2D Quantum Electron Solid in High Magnetic Field

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    The melting temperature (TmT_m) of a solid is generally determined by the pressure applied to it, or indirectly by its density (nn) through the equation of state. This remains true even for helium solids\cite{wilk:67}, where quantum effects often lead to unusual properties\cite{ekim:04}. In this letter we present experimental evidence to show that for a two dimensional (2D) solid formed by electrons in a semiconductor sample under a strong perpendicular magnetic field\cite{shay:97} (BB), the TmT_m is not controlled by nn, but effectively by the \textit{quantum correlation} between the electrons through the Landau level filling factor Μ\nu=nh/eBnh/eB. Such melting behavior, different from that of all other known solids (including a classical 2D electron solid at zero magnetic field\cite{grim:79}), attests to the quantum nature of the magnetic field induced electron solid. Moreover, we found the TmT_m to increase with the strength of the sample-dependent disorder that pins the electron solid.Comment: Some typos corrected and 2 references added. Final version with minor editoriol revisions published in Nature Physic

    Major contribution of the type II beta carbonic anhydrase CanB (Cj0237) to the capnophilic growth phenotype of Campylobacter jejuni

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    Campylobacter jejuni, the leading cause of human bacterial gastroenteritis, requires low environmental oxygen and high carbon dioxide for optimum growth, but the molecular basis for the carbon dioxide requirement is unclear. One factor may be inefficient conversion of gaseous CO2 to bicarbonate, the required substrate of various carboxylases. Two putative carbonic anhydrases (CAs) are encoded in the genome of C. jejuni strain NCTC 11168 (Cj0229 and Cj0237). Here, we show that the deletion of the cj0237 (canB) gene alone prevents growth in complex media at low (1% v/v) CO2 and significantly reduces the growth rate at high (5% v/v) CO2. In minimal media incubated under high CO2, the canB mutant grew on L-aspartate but not on the key C3 compounds L-serine, pyruvate and L-lactate, showing that CanB is crucial in bicarbonate provision for pyruvate carboxylase-mediated oxaloacetate synthesis. Nevertheless, purified CanB (a dimeric, anion and acetazolamide sensitive, zinc-containing type II beta-class enzyme) hydrates CO2 actively only above pH 8 and with a high Km (∌34 mM). At typical cytoplasmic pH values and low CO2, these kinetic properties might limit intracellular bicarbonate availability. Taken together, our data suggest CanB is a major contributor to the capnophilic growth phenotype of C. jejuni

    Local replication of simian immunodeficiency virus in the breast milk compartment of chronically-infected, lactating rhesus monkeys

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    Breast milk transmission remains a major mode of infant HIV acquisition, yet anatomic and immunologic forces shaping virus quasispecies in milk are not well characterized. In this study, phylogenic analysis of envelope sequences of milk SIV variants revealed groups of nearly identical viruses, indicating local virus production. However, comparison of the patterns and rates of CTL escape of blood and milk virus demonstrated only subtle differences between the compartments. These findings suggest that a substantial fraction of milk viruses are produced by locally-infected cells, but are shaped by cellular immune pressures similar to that in the blood

    Investigating the Effects of Pacific Sea Surface Temperatures on the Wind Drought of 2015 Over the United States

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    During the first quarter of 2015 the United States experienced a widespread and extended episode of low surface wind speeds. This episode had a strong impact on wind power generation. Some wind farms did not generate enough cash for their steady payments, and the value of some assets decreased. Although the wind industry expressed their concerns, the episode has not received much attention from the scientific community and remains weakly understood. In this paper we aim to fill this gap and advance understanding of the underlying processes at seasonal time scales. Using retrospective climate predictions, we find that high sea surface temperatures in the western tropical Pacific ocean associated with a strongly positive phase of the North Pacific Mode played a central role to establish and maintain those wind anomalies. In a more general way it has also been shown that interannual variability of wind speed over North America is not only dominated by El Niño/Southern Oscillation but also by other sea surface temperature variations in the tropical Pacific. This new knowledge can be useful for industry stakeholders to anticipate future periods of low wind speed.This work was funded by the EU projects S2S4E (GA 776787), EUCP (GA 776613), CLIM4ENERGY (C3S_441_Lot2_CEA), EUCLEIA (GA 607085), INDECIS (GA 690462), and MEDSCOPE (GA 690462). Omar Bellprat has been funded by the European Space Agency (ESA) Living Planet Fellowship Programme under the project VERITAS-CCI.We thank Daniel Cabezón for helping and informing on the wind drought episode and Javier García-Serrano for the insights on the interpretation of the physical processes. All the analyses have been performed using the statistical software R (R Core Team, 2015). The startR and s2dverification R packages have been used to read data sets, compute EOFs, and plot maps. Model output from the numerical experiments can be accessed through EUDAT facilities at the link http://doi.org/10.23728/b2share.71078 a8618414e9b906cfa6bb7d2cdab. The reanalysis data and models used are listed in the references. We also acknowledge Javier Vegas and Nicolau Manubens for technical support, as well as the EC-Earth consortium for the model development.Peer ReviewedPostprint (published version

    Synergistic effects of various Her inhibitors in combination with IGF-1R, C-MET and Src targeting agents in breast cancer cell lines

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    Introduction: Overexpression of the receptor tyrosine kinase HER2 has been reported in around 25% of human breast cancers, usually indicating a poor prognosis. As a result, HER2 has become a popular target for therapy. However, despite recent advances in HER2 targeted therapy, many patients still experience primary and secondary resistance to such treatments. It is therefore important to understand the underlying mechanism of resistance and to develop more effective therapeutic interventions for breast cancer. Methods: The sensitivity of a panel of seven breast cancer cell lines to treatment with various types HER-family inhibitors alone, or in combination with a selection of other tyrosine kinase inhibitors (TKIs) or chemotherapeutic agents was determined using the Sulforhodamine B colorimetric assay. Receptor expression, cell-cycle distribution, cell signalling and cell migration were determined using flow cytometry, Western blot and Incucyte Zoom Live-Cell Analysis System respectively. Results: Overall, breast cancer cells were more sensitive to treatment with the irreversible pan-HER family inhibitors, particularly afatinib and neratinib, than treatment with the first-generation reversible inhibitors. Of three HER-2 overexpressing cell lines in this panel, SKBr3 and BT474 were highly sensitive to treatment with HER-family inhibitors (IC50s as low as 3 nM), while MDA-MB-453 was relatively resistant (lowest IC50 = 0.11 ÎŒM). When the HER-family inhibitors were combined with other agents such as NVP-AEW541 (an IGF-1R inhibitor), dasatinib (a Src inhibitor) or crizotinib (a c-Met/ALK inhibitor), such combination produced synergistic effects in some of the cell lines examined. Interestingly, co-targeting of Src and HER-family members in MDA-MB-453 cells led to synergistic growth inhibition, suggesting the importance of Src in mediating resistance to HER2-targeting agents. Finally, treatment with the irreversible HER family blockers and dasatinib were also most effective at inhibiting the migration of breast cancer cells. Conclusion: We concluded that the irreversible inhibitors of HER-family members are generally more effective at inhibiting growth, downstream signalling and migration compared with reversible inhibitors, and that combining HER-family inhibitors with other TKIs such as dasatinib may have therapeutic advantages in certain breast cancer subtypes and warrants further investigation

    sodC-Based Real-Time PCR for Detection of Neisseria meningitidis

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    Real-time PCR (rt-PCR) is a widely used molecular method for detection of Neisseria meningitidis (Nm). Several rt-PCR assays for Nm target the capsule transport gene, ctrA. However, over 16% of meningococcal carriage isolates lack ctrA, rendering this target gene ineffective at identification of this sub-population of meningococcal isolates. The Cu-Zn superoxide dismutase gene, sodC, is found in Nm but not in other Neisseria species. To better identify Nm, regardless of capsule genotype or expression status, a sodC-based TaqMan rt-PCR assay was developed and validated. Standard curves revealed an average lower limit of detection of 73 genomes per reaction at cycle threshold (Ct) value of 35, with 100% average reaction efficiency and an average R2 of 0.9925. 99.7% (624/626) of Nm isolates tested were sodC-positive, with a range of average Ct values from 13.0 to 29.5. The mean sodC Ct value of these Nm isolates was 17.6±2.2 (±SD). Of the 626 Nm tested, 178 were nongroupable (NG) ctrA-negative Nm isolates, and 98.9% (176/178) of these were detected by sodC rt-PCR. The assay was 100% specific, with all 244 non-Nm isolates testing negative. Of 157 clinical specimens tested, sodC detected 25/157 Nm or 4 additional specimens compared to ctrA and 24 more than culture. Among 582 carriage specimens, sodC detected Nm in 1 more than ctrA and in 4 more than culture. This sodC rt-PCR assay is a highly sensitive and specific method for detection of Nm, especially in carriage studies where many meningococcal isolates lack capsule genes

    Worldwide trends in diabetes since 1980: a pooled analysis of 751 population-based studies with 4.4 million participants

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    BACKGROUND: One of the global targets for non-communicable diseases is to halt, by 2025, the rise in the age-standardised adult prevalence of diabetes at its 2010 levels. We aimed to estimate worldwide trends in diabetes, how likely it is for countries to achieve the global target, and how changes in prevalence, together with population growth and ageing, are affecting the number of adults with diabetes. METHODS: We pooled data from population-based studies that had collected data on diabetes through measurement of its biomarkers. We used a Bayesian hierarchical model to estimate trends in diabetes prevalence—defined as fasting plasma glucose of 7·0 mmol/L or higher, or history of diagnosis with diabetes, or use of insulin or oral hypoglycaemic drugs—in 200 countries and territories in 21 regions, by sex and from 1980 to 2014. We also calculated the posterior probability of meeting the global diabetes target if post-2000 trends continue. FINDINGS: We used data from 751 studies including 4 372 000 adults from 146 of the 200 countries we make estimates for. Global age-standardised diabetes prevalence increased from 4·3% (95% credible interval 2·4–7·0) in 1980 to 9·0% (7·2–11·1) in 2014 in men, and from 5·0% (2·9–7·9) to 7·9% (6·4–9·7) in women. The number of adults with diabetes in the world increased from 108 million in 1980 to 422 million in 2014 (28·5% due to the rise in prevalence, 39·7% due to population growth and ageing, and 31·8% due to interaction of these two factors). Age-standardised adult diabetes prevalence in 2014 was lowest in northwestern Europe, and highest in Polynesia and Micronesia, at nearly 25%, followed by Melanesia and the Middle East and north Africa. Between 1980 and 2014 there was little change in age-standardised diabetes prevalence in adult women in continental western Europe, although crude prevalence rose because of ageing of the population. By contrast, age-standardised adult prevalence rose by 15 percentage points in men and women in Polynesia and Micronesia. In 2014, American Samoa had the highest national prevalence of diabetes (>30% in both sexes), with age-standardised adult prevalence also higher than 25% in some other islands in Polynesia and Micronesia. If post-2000 trends continue, the probability of meeting the global target of halting the rise in the prevalence of diabetes by 2025 at the 2010 level worldwide is lower than 1% for men and is 1% for women. Only nine countries for men and 29 countries for women, mostly in western Europe, have a 50% or higher probability of meeting the global target. INTERPRETATION: Since 1980, age-standardised diabetes prevalence in adults has increased, or at best remained unchanged, in every country. Together with population growth and ageing, this rise has led to a near quadrupling of the number of adults with diabetes worldwide. The burden of diabetes, both in terms of prevalence and number of adults affected, has increased faster in low-income and middle-income countries than in high-income countries. FUNDING: Wellcome Trust

    Search for resonances in the mass distribution of jet pairs with one or two jets identified as b-jets in proton–proton collisions at √s=13TeV with the ATLAS detector

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    Searches for high-mass resonances in the dijet invariant mass spectrum with one or two jets identi-fied as b-jets are performed using an integrated luminosity of 3.2fb−1of proton–proton collisions with a centre-of-mass energy of √s=13TeVrecorded by the ATLAS detector at the Large Hadron Collider. Noevidence of anomalous phenomena is observed in the data, which are used to exclude, at 95%credibility level, excited b∗quarks with masses from 1.1TeVto 2.1TeVand leptophobic Z bosons with masses from 1.1TeVto 1.5TeV. Contributions of a Gaussian signal shape with effective cross sections ranging from approximately 0.4 to 0.001pb are also excluded in the mass range 1.5–5.0TeV

    A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)

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