Mesoscopic behaviour of the neutral Fermi gas He-3 confined in quantum wires

The behaviour of electron gases in restricted geometries provides a means to explore the fundamental quantum-mechanical properties of fermion gases at mesoscopic length scales(1). But the existence of Coulomb repulsion between electrons unavoidably complicates the physics. Quantum gases of neutral fermions-such as He-3 quasiparticles in a dilute solution of He-3 in He-4, cooled to millikelvin temperatures(2)-therefore offer a means of probing regimes completely inaccessible to electronic systems. Here we demonstrate the quantum exclusion of a He-3 fermion gas from a network of narrow channels, connected to a reservoir of He-3/He-4 solution. The effect is expected from simple quantum-mechanical arguments, which predict that the He-3 atoms cannot enter the channels when their wavelength exceeds root 2 times the channel width. By adjusting the temperature of the solution, the energy of the particles and hence their average wavelength can be controlled. In this way, we observe temperature-dependent changes in the penetration of the 3He quasiparticles into the channels. Our results demonstrate the macroscopic response of an atomic gas to basic quantum-mechanical restrictions at the mesoscopic level

Circulating neutrophil transcriptome may reveal intracranial aneurysm signature

<div><p>Background</p><p>Unruptured intracranial aneurysms (IAs) are typically asymptomatic and undetected except for incidental discovery on imaging. Blood-based diagnostic biomarkers could lead to improvements in IA management. This exploratory study examined circulating neutrophils to determine whether they carry RNA expression signatures of IAs.</p><p>Methods</p><p>Blood samples were collected from patients receiving cerebral angiography. Eleven samples were collected from patients with IAs and 11 from patients without IAs as controls. Samples from the two groups were paired based on demographics and comorbidities. RNA was extracted from isolated neutrophils and subjected to next-generation RNA sequencing to obtain differential expressions for identification of an IA-associated signature. Bioinformatics analyses, including gene set enrichment analysis and Ingenuity Pathway Analysis, were used to investigate the biological function of all differentially expressed transcripts.</p><p>Results</p><p>Transcriptome profiling identified 258 differentially expressed transcripts in patients with and without IAs. Expression differences were consistent with peripheral neutrophil activation. An IA-associated RNA expression signature was identified in 82 transcripts (p<0.05, fold-change ≥2). This signature was able to separate patients with and without IAs on hierarchical clustering. Furthermore, in an independent, unpaired, replication cohort of patients with IAs (n = 5) and controls (n = 5), the 82 transcripts separated 9 of 10 patients into their respective groups.</p><p>Conclusion</p><p>Preliminary findings show that RNA expression from circulating neutrophils carries an IA-associated signature. These findings highlight a potential to use predictive biomarkers from peripheral blood samples to identify patients with IAs.</p></div

Biennale d'art performatif de Rouyn-Noranda 2014

Providing an appropriate education for exceptional students in mathematics is mandated in educational policy in Australasia (Australian Curriculum, Assessment and Reporting Agency (ACARA), 2010; Ministry of Education, 2009, 2011) but a challenge for teachers and schools. ‘Exceptional students’ refer to two distinct populations, namely those who are gifted in mathematics and have the capability to perform very highly compared to age peers and those who experience learning difficulties in mathematics and may underperform (Diezmann, Lowrie, Bicknell, Faragher, &amp; Putt, 2004)