LOX manifold tee analysis

A 4000 Hz vibration phenomena was observed during the test firings of several space shuttle main engines (SSME). Experimental studies of this phenomena suggest that the problem might be associated with vortex shedding from the vanes within the LOX tee manifold. The objective of this study was to determine the unsteady, 3-D flow associated with these vanes by computational methods to identify and better understand the 4000 Hz vibration phenomena. A flow solver, FDNS, for the turbulent conservation equations was validated for predicting high frequency vortex dynamics and used to predict 2-D and 3-D flows within the LOX tee. 4000 Hz excitation oscillations were predicted for some flows and the entire 3-D flow structure was predicted for LOX tee flow. The complexity of the flow was revealed by this analysis, and computational methods for predicting these high frequency oscillations in future engine systems were established

NMR solution structure of a chymotrypsin inhibitor from the Taiwan cobra Naja naja atra

The Taiwan cobra (Naja naja atra) chymotrypsin inhibitor (NACI) consists of 57 amino acids and is related to other Kunitz-type inhibitors such as bovine pancreatic trypsin inhibitor (BPTI) and Bungarus fasciatus fraction IX (BF9), another chymotrypsin inhibitor. Here we present the solution structure of NACI. We determined the NMR structure of NACI with a root-mean-square deviation of 0.37 Å for the backbone atoms and 0.73 Å for the heavy atoms on the basis of 1,075 upper distance limits derived from NOE peaks measured in its NOESY spectra. To investigate the structural characteristics of NACI, we compared the three-dimensional structure of NACI with BPTI and BF9. The structure of the NACI protein comprises one 310-helix, one α-helix and one double-stranded antiparallel β-sheet, which is comparable with the secondary structures in BPTI and BF9. The RMSD value between the mean structures is 1.09 Å between NACI and BPTI and 1.27 Å between NACI and BF9. In addition to similar secondary and tertiary structure, NACI might possess similar types of protein conformational fluctuations as reported in BPTI, such as Cys14–Cys38 disulfide bond isomerization, based on line broadening of resonances from residues which are mainly confined to a region around the Cys14–Cys38 disulfide bond

A Note on Noncommutative D-Brane Actions

We use the nonabelian action of N coincident D(-1) branes in constant background fields, in the N $\to \infty$ limit, to construct noncommutative D-brane actions in an arbitrary noncommutative description and comment on tachyon condensation from this perspective.Comment: 11 pages, LaTeX (v2: references added, typos fixed

Leadership curricula and assessment in Australian and New Zealand medical schools

Background: The Australian Medical Council, which accredits Australian medical schools, recommends medical leadership graduate outcomes be taught, assessed and accredited. In Australia and New Zealand (Australasia) there is a significant research gap and no national consensus on how to educate, assess, and evaluate leadership skills in medical professional entry degree/programs. This study aims to investigate the current curricula, assessment and evaluation of medical leadership in Australasian medical degrees, with particular focus on the roles and responsibilities of medical leadership teachers, frameworks used and competencies taught, methods of delivery, and barriers to teaching leadership. Methods: A self-administered cross-sectional survey was distributed to senior academics and/or heads or Deans of Australasian medical schools. Data for closed questions and ordinal data of each Likert scale response were described via frequency analysis. Content analysis was undertaken on free text responses and coded manually. Results: Sixteen of the 22 eligible (73%) medical degrees completed the full survey and 100% of those indicate that leadership is taught in their degree. In most degrees (11, 69%) leadership is taught as a common theme integrated throughout the curricula across several subjects. There is a variety of leadership competencies taught, with strengths being communication (100%), evidence based practice (100%), critical reflective practice (94%), self-management (81%), ethical decision making (81%), critical thinking and decision making (81%). Major gaps in teaching were financial management (20%), strategic planning (31%) and workforce planning (31%). The teaching methods used to deliver medical leadership within the curricula are diverse, with many degrees providing opportunities for leadership teaching for students outside the curricula. Most degrees (10, 59%) assess the leadership education, with one-third (6, 35%) evaluating it. Conclusions: Medical leadership competencies are taught in most degrees, but key leadership competencies are not being taught and there appears to be no continuous quality improvement process for leadership education. There is much more we can do as medical educators, academics and leaders to shape professional development of academics to teach medical leadership, and to agree on required leadership skills set for our students so they can proactively shape the future of the health care system

Butterfly Tachyons in Vacuum String Field Theory

We use geometrical conformal field theory methods to investigate tachyon fluctuations about the butterfly projector state in Vacuum String Field Theory. We find that the on-shell condition for the tachyon field is equivalent to the requirement that the quadratic term in the string-field action vanish on shell. This further motivates the interpretation of the butterfly state as a D-brane. We begin a calculation of the tension of the butterfly, and conjecture that this will match the case of the sliver and further strengthen this interpretation.Comment: 14 pages, 6 figures, revte