2,620 research outputs found
Phonons of graphene and graphitic materials derived from the empirical potential LCBOPII
We present the interatomic force constants and phonon dispersions of graphite
and graphene from the LCBOPII empirical bond order potential. We find a good
agreement with experimental results, particularly in comparison to other bond
order potentials. From the flexural mode we determine the bending rigidity of
graphene to be 0.69 eV at zero temperature. We discuss the large increase of
this constant with temperature and argue that derivation of force constants
from experimental values should take this feature into account. We examine also
other graphitic systems, including multilayer graphene for which we show that
the splitting of the flexural mode can provide a tool for characterization
Pathfinder first light: alignment, calibration, and commissioning of the LINC-NIRVANA ground-layer adaptive optics subsystem
We present descriptions of the alignment and calibration tests of the
Pathfinder, which achieved first light during our 2013 commissioning campaign
at the LBT. The full LINC-NIRVANA instrument is a Fizeau interferometric imager
with fringe tracking and 2-layer natural guide star multi-conjugate adaptive
optics (MCAO) systems on each eye of the LBT. The MCAO correction for each side
is achieved using a ground layer wavefront sensor that drives the LBT adaptive
secondary mirror and a mid-high layer wavefront sensor that drives a Xinetics
349 actuator DM conjugated to an altitude of 7.1 km. When the LINC-NIRVANA MCAO
system is commissioned, it will be one of only two such systems on an 8-meter
telescope and the only such system in the northern hemisphere. In order to
mitigate risk, we take a modular approach to commissioning by decoupling and
testing the LINC-NIRVANA subsystems individually. The Pathfinder is the
ground-layer wavefront sensor for the DX eye of the LBT. It uses 12 pyramid
wavefront sensors to optically co-add light from natural guide stars in order
to make four pupil images that sense ground layer turbulence. Pathfinder is now
the first LINC-NIRVANA subsystem to be fully integrated with the telescope and
commissioned on sky. Our 2013 commissioning campaign consisted of 7 runs at the
LBT with the tasks of assembly, integration and communication with the LBT
telescope control system, alignment to the telescope optical axis, off-sky
closed loop AO calibration, and finally closed loop on-sky AO. We present the
programmatics of this campaign, along with the novel designs of our alignment
scheme and our off-sky calibration test, which lead to the Pathfinder's first
on-sky closed loop images
Symmetry constraints on phonon dispersion in graphene
Taking into account the constraints imposed by the lattice symmetry, we
calculate the phonon dispersion for graphene with interactions between the
first, second, and third nearest neighbors in the framework of the Born--von
Karman model. Analytical expressions obtained for the dispersion of the
out-of-plane (bending) modes give the nonzero sound velocity. The dispersion of
four in-plane modes is determined by coupled equations. Values of the force
constants are found in fitting with frequencies at critical points and with
elastic constants measured on graphite.Comment: 5 pages, 2 figure
Reconstructing Lincoln Log Cabin: The Civilian Conservation Corps in Coles County
The symposium Reconstructing Lincoln Log Cabin: The Civilian Conservation Corps in Coles County traced the origins of Lincoln Log Cabin and the activities of the Civilian Conservation Corps in Coles County, Illinois. Students researched, designed, and implemented all phases of the symposium held at the Lincoln Log Cabin State Historic Site on Saturday, November 2011 from 9 a.m. to 12:00 noon. The Historical Administration Program at Eastern Illinois University and the Lincoln-Sargent Farm Foundation jointly sponsored the symposium. Selected students made formal power-point presentations and facilitated questions from the audience at the conclusion of their presentations. The students unearthed a wealth of new information and presented a layered interpretation of the site\u27s history and the CCC as a case study of national history localized. The presentations focused on the community groups and individuals involved in creating the site, the construction of buildings by the Civilian Conservation Corp in 1934-35, and ended with the public opening in August 1936
I Didn\u27t Mean To Make You Cry
https://digitalcommons.library.umaine.edu/mmb-vp/1645/thumbnail.jp
The Police Won\u27t Let Mariucha Dance : Unless She Move Da Feet
https://digitalcommons.library.umaine.edu/mmb-vp/4990/thumbnail.jp
The alternative serotonin transporter promoter P2 impacts gene function in females with irritable bowel syndrome
Irritable bowel syndrome (IBS) is a gut-brain disorder in which symptoms are shaped by serotonin acting centrally and peripherally. The serotonin transporter gene SLC6A4 has been implicated in IBS pathophysiology, but the underlying genetic mechanisms remain unclear. We sequenced the alternative P2 promoter driving intestinal SLC6A4 expression and identified single nucleotide polymorphisms (SNPs) that were associated with IBS in a discovery sample. Identified SNPs built different haplotypes, and the tagging SNP rs2020938 seems to associate with constipation-predominant IBS (IBS-C) in females. rs2020938 validation was performed in 1978 additional IBS patients and 6,038 controls from eight countries. Meta-analysis on data from 2,175 IBS patients and 6,128 controls confirmed the association with female IBS-C. Expression analyses revealed that the P2 promoter drives SLC6A4 expression primarily in the small intestine. Gene reporter assays showed a functional impact of SNPs in the P2 region. In silico analysis of the polymorphic promoter indicated differential expression regulation. Further follow-up revealed that the major allele of the tagging SNP rs2020938 correlates with differential SLC6A4 expression in the jejunum and with stool consistency, indicating functional relevance. Our data consolidate rs2020938 as a functional SNP associated with IBS-C risk in females, underlining the relevance of SLC6A4 in IBS pathogenesis
Two-loop corrections to the decay rate of parapositronium
Order corrections to the decay rate of parapositronium are
calculated. A QED scattering calculation of the amplitude for electron-positron
annihilation into two photons at threshold is combined with the technique of
effective field theory to determine an NRQED Hamiltonian, which is then used in
a bound state calculation to determine the decay rate. Our result for the
two-loop correction is in units of times the
lowest order rate. This is consistent with but more precise than the result
of a previous calculation.Comment: 26 pages, 7 figure
Attachment and coping in psychosis in relation to spiritual figures
Background: Studies have found higher levels of insecure attachment in individuals with schizophrenia. Attachment theory provides a framework necessary for conceptualizing the development of interpersonal functioning. Some aspects of the attachment of the believer to his/her spiritual figure are similar to those between the child and his/her parents. The correspondence hypothesis suggests that early child-parent interactions correspond to a person's relation to a spiritual figure. The compensation hypothesis suggests that an insecure attachment history would lead to a strong religiousness/spirituality as a compensation for the lack of felt security. The aim of this study is to explore attachment models in psychosis vs. healthy controls, the relationships between attachment and psychopathology and the attachment processes related to spiritual figures.
Methods: Attachment models were measured in 30 patients with psychosis and 18 controls with the AAI (Adult Attachment interview) in relationship with psychopathology. Beliefs and practices related to a spiritual figure were investigated by qualitative and quantitative analyses.
Results: Patients with psychosis showed a high prevalence of insecure avoidant attachment. Spiritual entities functioned like attachment figures in two thirds of cases. Interviews revealed the transformation of internal working models within relation to a spiritual figure: a compensation process was found in 7 of the 32 subjects who showed a significant attachment to a spiritual figure.
Conclusions: Attachment theory allows us to highlight one of the underlying dimensions of spiritual coping in patients with psychosis
Search for Second-Generation Scalar Leptoquarks in Collisions at =1.96 TeV
Results on a search for pair production of second generation scalar
leptoquark in collisions at =1.96 TeV are reported. The
data analyzed were collected by the CDF detector during the 2002-2003 Tevatron
Run II and correspond to an integrated luminosity of 198 pb. Leptoquarks
(LQ) are sought through their decay into (charged) leptons and quarks, with
final state signatures represented by two muons and jets and one muon, large
transverse missing energy and jets. We observe no evidence for production
and derive 95% C.L. upper limits on the production cross sections as well
as lower limits on their mass as a function of , where is the
branching fraction for .Comment: 9 pages (3 author list) 5 figure
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