23,677 research outputs found

    Site specific spin dynamics in BaFe2As2: tuning the ground state by orbital differentiation

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    The role of orbital differentiation on the emergence of superconductivity in the Fe-based superconductors remains an open question to the scientific community. In this investigation, we employ a suitable microscopic spin probe technique, namely Electron Spin Resonance (ESR), to investigate this issue on selected chemically substituted BaFe2_{2}As2_{2} single crystals. As the spin-density wave (SDW) phase is suppressed, we observe a clear increase of the Fe 3dd bands anisotropy along with their localization at the FeAs plane. Such an increase of the planar orbital content interestingly occurs independently on the chemical substitution responsible for suppressing the SDW phase. As a consequence, the magnetic fluctuations combined with the resultant particular symmetry of the Fe 3dd bands are propitious ingredients to the emergence of superconductivity in this class of materials.Comment: 6 pages, 5 figure

    African-American patients with cancer Talking About Clinical Trials (TACT) with oncologists during consultations: evaluating the efficacy of tailored health messages in a randomised controlled trial—the TACT study protocol

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    Introduction Low rates of accrual of African-American (AA) patients with cancer to therapeutic clinical trials (CTs) represent a serious and modifiable racial disparity in healthcare that impedes the development of promising cancer therapies. Suboptimal physician–patient consultation communication is a barrier to the accrual of patients with cancer of any race, but communication difficulties are compounded with AA patients. Providing tailored health messages (THM) to AA patients and their physician about CTs has the potential to improve communication, lower barriers to accrual and ameliorate health disparities. Objective (1) Demonstrate the efficacy of THM to increase patient activation as measured by direct observation. (2) Demonstrate the efficacy of THM to improve patient outcomes associated with barriers to AA participation. (3) Explore associations among preconsultation levels of: (A) trust in medical researchers, (B) knowledge and attitudes towards CTs, (C) patient-family member congruence in decision-making, and (D) involvement/information preferences, and group assignment. Methods and analysis First, using established methods, we will develop THM materials. Second, the efficacy of the intervention is determined in a 2 by 2 factorial randomised controlled trial to test the effectiveness of (1) providing 357 AA patients with cancer with THM with 2 different ‘depths’ of tailoring and (2) either providing feedback to oncologists about the patients\u27 trial THM or not. The primary analysis compares patient engaged communication in 4 groups preconsultation and postconsultation. Ethics and dissemination This study was approved by the Virginia Commonwealth University Institutional Review Board. To facilitate use of the THM intervention in diverse settings, we will convene ‘user groups’ at 3 major US cancer centres. To facilitate dissemination, we will post all materials and the implementation guide in publicly available locations

    Dynamic Behavior of Soils From Field and Laboratory Tests

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    Both geophysical and laboratory tests were used to determine the dynamic shear moduli of medium stiff to hard clays and silts at six sites. The geophysical measurements included conventional downhole tests conducted at low strain levels and modified cross-hole impulse tests conducted over a wide range of strains. Laboratory resonant column and cyclic triaxial tests were performed on soil samples retrieved from borings made at the sites. The results from both the field and laboratory tests of the medium stiff to stiff sols showed fairly good agreement. The laboratory test results of the hard clays and silts, however, were typically half the values of the field tests at corresponding strain levels. This would suggest the need for adjusting the laboratory results performed on hard cohesive soils. Also, the field test results suggest that as soil stiffness increases, the modulus attenuation rate with strain decreases
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