Vibrating Wire Thermometry in Superfluid 3He

We report systematic measurements of the response of a Vibrating Wire Resonator (VWR) in normal and superfluid liquid ³He. Special attention has been paid to the hydrodynamic regime of the superfluid B-phase, where the response parameters of the VWR do not follow a simple law. We show that a simple interpolation between the region where first order slip-corrections can be applied and the ballistic regime is insufficient. Measuring an empirical effective viscosity, we propose a temperature calibration method which allows the use of VWRs as a secondary thermometer at intermediate and high pressures in the temperature range 0.2 T _c < T < 50 mK.     

Recursive optimal pruning with applications to tree structuredvector quantizers

A pruning algorithm of P.A. Chou et al. (1989) for designing optimal tree structures identifies only those codebooks which lie on the convex hull of the original codebook's operational distortion rate function. The authors introduce a modified version of the original algorithm, which identifies a large number of codebooks having minimum average distortion, under the constraint that, in each step, only modes having no descendents are removed from the tree. All codebooks generated by the original algorithm are also generated by this algorithm. The new algorithm generates a much larger number of codebooks in the middle- and low-rate regions. The additional codebooks permit operation near the codebook's operational distortion rate function without time sharing by choosing from the increased number of available bit rates. Despite the statistical mismatch which occurs when coding data outside the training sequence, these pruned codebooks retain their performance advantage over full search vector quantizers (VQs) for a large range of rates.     

Centurion syndrome. Idiopathic anterior displacement of the medial canthus

Bone marrow transplantation (BMT) using HLA-partially matched family donors has produced disappointing results (25-30% of long-term survivors) in patients with severe aplastic anemia. We describe two children affected by severe aplastic anemia, not responsive to immunosuppressive therapy, who underwent allogeneic bone marrow transplantation using a HLA-partially matched family donor. Both cases presented 2 first class HLA-antigens (A and B) disparity between donor and recipient. The pretransplant conditioning regimen consisted of cyclophosphamide, thoracoabdominal irradiation, cytosine-arabinoside, and antilymphocyte globulin. As graft versus host disease (GVHD) prophylaxis, Cyclosporine-A was administered at usual dosages for 6 months. A full marrow engraftment was observed in both cases. Only grade I acute GVHD, promptly responsive to corticosteroid therapy, developed with no chronic GVHD. Five months after transplant, both children progressively developed hypertension, renal function impairment, thrombocytopenia, and severe normochromic anemia, with erythropoietin serum levels lower than expected for the haematocrit. After antihypertension treatment and supportive therapy, the clinical picture progressively improved, while treatment with recombinant human erythropoietin completely corrected the long-lasting anemia. The two children are alive and well 28 months after the transplant, with a Karnofsky score of 100% and a normal peripheral blood count. The authors suggest that, once immunosuppressive therapy has failed, BMT from donors other than HLA-identical sibling is a feasible approach in children affected by severe aplastic anemia, not having an HLA-identical donor.     

A limit analysis of nonlinear elastic lateral displacements of thin-walled reinforced and prestressed beams

An incremental iterative process based on direct energy minimization is presented for a limit analysis of nonlinear elastic lateral displacements and twists of reinforced and prestressed beams. Problems encountered with the constitutive relations are discussed and two possible material models are presented.     

The partial testing design: a less costly way to test equivalence for sensitivity and specificity

We propose a new, less costly, design to test the equivalence of digital versus analogue mammography in terms of sensitivity and specificity. Because breast cancer is a rare event among asymptomatic women, the sample size for testing equivalence of sensitivity is larger than that for testing equivalence of specificity. Hence calculations of sample size are based on sensitivity. With the proposed design it is possible to achieve the same power as a completely paired design by increasing the number of less costly analogue mammograms and not giving the more expensive digital mammograms to some randomly selected subjects who are negative on the analogue mammogram. The key idea is that subjects who are negative on the analogue mammogram are unlikely to have cancer and hence contribute less information for estimating sensitivity than subjects who are positive on the analogue mammogram. To ascertain disease state among subjects not biopsied, we propose another analogue mammogram at a later time determined by a natural history model. The design differs from a double sampling design because it compares two imperfect tests instead of combining information from a perfect and imperfect test.     

Structures stabilizing the dimer interface on human 11 beta-hydroxysteroid dehydrogenase types 1 and 2 and human 15-hydroxyprostaglandin dehydrogenase and their homologs

Human 11 beta-hydroxysteroid dehydrogenase-types 1 and 2 and human 15-hydroxyprostaglandin dehydrogenase belong to a large family of oxidoreductases that includes human dihydropteridine reductase and Streptomyces hydrogenans 20 beta-hydroxysteroid dehydrogenase, for which 3D structures are available. Almost all of these enzymes are either dimers or tetramers. The dimer interface of rat dihydropteridine reductase consists of alpha-helices E and F from each monomer arranged in a four alpha-helix bundle [Varughese et al. (1992) Proc. Natl. Acad. Sci. USA 89, 6080-6084]. Alpha-helix F contains tyrosine-146 and lysine-150, residues that are highly conserved in this protein superfamily and have been proposed to be at the catalytic site. We have examined the dimer interface between alpha-helix F in human and rat dihydropteridine reductase and Streptomyces hydrogenans 20 beta-hydroxysteroid dehydrogenase as well as modeled 3D structures of steroid and prostaglandin dehydrogenases and homologs for stabilizing interactions. We find a site in the middle of alpha-helix F that stabilizes the dimer. This anchor is adjacent to conserved lysine on alpha-helix F. Our analysis suggests that sequence variation in the anchor may be important in substrate specificity.     

When is the shape of a scene unique given its light-field: a fundamental theorem of 3D vision?

The complete set of measurements that could ever be used by a passive 3D vision algorithm is the plenoptic function or light-field. We give a concise characterization of when the light-field of a Lambertian scene uniquely determines its shape and, conversely, when the shape is inherently ambiguous. In particular, we show that stereo computed from the light-field is ambiguous if and only if the scene is radiating light of a constant intensity (and color, etc.) over an extended region.     

SOLUBILISATION OF NITROGENOUS CONSTITUENTS OF BREWERS' SPENT GRAIN

The extraction of nitrogenous material from Brewers' spent grain (BSG) by solvents (water, sodium chloride solution, aqueous alcohol, acidic and alkaline solutions) commonly used to extract cereal proteins, resulted in the relatively low (0·2 to 8·5%) recovery of the total nitrogen. The recovery of nitrogenous material by the use of aqueous alkaline solutions was increased from 3–4% to 41% when the BSG was subjected to cellulase incubation prior to extraction. Approximately 75% of the nitrogen was solubilized with trifluoracetic acid. Detergent solutions (acid, neutral) solubilized more than 80% of the total nitrogen of the BSG. The low solubility of the nitrogenous constituents by conventional protein solvents could be the result of association between cellulosic material and protein.     

Majority and minority influence: Source-position imbalance as a determinant of message scrutiny.

Two experiments addressed the issue of whether endorsement of a position by a numerical majority or a minority leads to greater scrutiny of the information presented in a persuasive message. In Exp 1, a counterattitudinal position was endorsed by a majority or a minority and was supported by strong or weak arguments. Argument quality had a larger impact on attitudes with majority than with minority endorsement. In Exp 2, a proattitudinal or a counterattitudinal message was endorsed by a majority or a minority and was supported by strong or weak arguments. When the source and message position were unexpected (i.e., majority-counter and minority-pro messages), argument quality had a larger impact on attitudes than when the source and message position were expected (i.e., majority-pro and minority-counter messages). Thus, either majority or minority endorsement can enhance message scrutiny if the source-position pairing is surprising. (PsycINFO Database Record (c) 2010 APA, all rights reserved)