55 research outputs found

    Redesign of the Online Calculus Placement Test

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    In 2007, WPI implemented online Calculus Placement Tests. During the 2007-2008 academic year, a statistical analysis was performed for this new system. The same system was used again in 2008 and this project repeats the previous analysis and also introduces two significant changes to improve the original system. One change reduces the number of tests and simplifies the recommendation algorithm. The second change is a system to tailor the recommendation to each student\u27s intended major and background

    Unconventional Hund Metal in a Weak Itinerant Ferromagnet

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    The physics of weak itinerant ferromagnets is challenging due to their small magnetic moments and the ambiguous role of local interactions governing their electronic properties, many of which violate Fermi liquid theory. While magnetic fluctuations play an important role in the materials' unusual electronic states, the nature of these fluctuations and the paradigms through which they arise remain debated. Here we use inelastic neutron scattering to study magnetic fluctuations in the canonical weak itinerant ferromagnet MnSi. Data reveal that short-wavelength magnons continue to propagate until a mode crossing predicted for strongly interacting quasiparticles is reached, and the local susceptibility peaks at a coherence energy predicted for a correlated Hund metal by first-principles many-body theory. Scattering between electrons and orbital and spin fluctuations in MnSi can be understood at the local level to generate non-Fermi liquid character. These results provide crucial insight into the role of interorbital Hund's exchange within the broader class of enigmatic multiband itinerant, weak ferromagnets.Comment: 17 pages, 4 figure

    Genetic and Functional Dissection of HTRA1 and LOC387715 in Age-Related Macular Degeneration

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    A common haplotype on 10q26 influences the risk of age-related macular degeneration (AMD) and encompasses two genes, LOC387715 and HTRA1. Recent data have suggested that loss of LOC387715, mediated by an insertion/deletion (in/del) that destabilizes its message, is causally related with the disorder. Here we show that loss of LOC387715 is insufficient to explain AMD susceptibility, since a nonsense mutation (R38X) in this gene that leads to loss of its message resides in a protective haplotype. At the same time, the common disease haplotype tagged by the in/del and rs11200638 has an effect on the transcriptional upregulation of the adjacent gene, HTRA1. These data implicate increased HTRA1 expression in the pathogenesis of AMD and highlight the importance of exploring multiple functional consequences of alleles in haplotypes that confer susceptibility to complex traits

    Variants in the fetal genome near pro-inflammatory cytokine genes on 2q13 associate with gestational duration

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    The duration of pregnancy is influenced by fetal and maternal genetic and non-genetic factors. Here we report a fetal genome-wide association meta-analysis of gestational duration, and early preterm, preterm, and postterm birth in 84,689 infants. One locus on chromosome 2q13 is associated with gestational duration; the association is replicated in 9,291 additional infants (combined P= 3.96 x 10(-14)). Analysis of 15,588 mother-child pairs shows that the association is driven by fetal rather than maternal genotype. Functional experiments show that the lead SNP, rs7594852, alters the binding of the HIC1 transcriptional repressor. Genes at the locus include several interleukin 1 family members with roles in pro-inflammatory pathways that are central to the process of parturition. Further understanding of the underlying mechanisms will be of great public health importance, since giving birth either before or after the window of term gestation is associated with increased morbidity and mortality.Peer reviewe

    Variants in the fetal genome near pro-inflammatory cytokine genes on 2q13 associate with gestational duration

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    The duration of pregnancy is influenced by fetal and maternal genetic and non-genetic factors. Here we report a fetal genome-wide association meta-analysis of gestational duration, and early preterm, preterm, and postterm birth in 84,689 infants. One locus on chromosome 2q13 is associated with gestational duration; the association is replicated in 9,291 additional infants (combined P= 3.96 x 10(-14)). Analysis of 15,588 mother-child pairs shows that the association is driven by fetal rather than maternal genotype. Functional experiments show that the lead SNP, rs7594852, alters the binding of the HIC1 transcriptional repressor. Genes at the locus include several interleukin 1 family members with roles in pro-inflammatory pathways that are central to the process of parturition. Further understanding of the underlying mechanisms will be of great public health importance, since giving birth either before or after the window of term gestation is associated with increased morbidity and mortality

    Case report: Ocular signs of superficial siderosis; a rare neurodegenerative disorder

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    Aim: This article seeks to describe superficial siderosis as a rare, acquired neurodegenerative disorder and provide a case report of the neuro-ophthalmological clinical signs of a patient presenting with previously undiagnosed superficial siderosis. Report: A 48-year-old female with a previous history of motor vehicle trauma and recurrent migranous headaches presented with seizure. Additionally, she described blurred vision and serial fundus examination revealed retinal haemorrhage followed by papilledema. Subsequent radiological investigation revealed superficial siderosis. Conclusions: To our knowledge, this is the first report of retinal findings in a case of superficial siderosis. The case report seeks to provide clinicians with a wider breadth of information on the clinical presentation and response to intracranial pressure lowering therapy in a rare condition
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