Collapsible reflector Patent

Self erecting parabolic reflector design for use in spac

Bohr's 1913 molecular model revisited

It is generally believed that the old quantum theory, as presented by Niels Bohr in 1913, fails when applied to few electron systems, such as the H2 molecule. Here we find new solutions within the Bohr theory that describe the potential energy curve for the lowest singlet and triplet states of H2 about as well as the early wave mechanical treatment of Heitler and London. We also develop a new interpolation scheme which substantially improves the agreement with the exact ground state potential curve of H2 and provides a good description of more complicated molecules such as LiH, Li2, BeH and He2.Comment: 6 pages, 9 figure

Pathogenicity of anti-ADAMTS13 autoantibodies in acquired thrombotic thrombocytopenic purpura.

BACKGROUND: Acquired thrombotic thrombocytopenic purpura (TTP) is an autoimmune disease in which anti-ADAMTS13 autoantibodies cause severe enzyme deficiency. ADAMTS13 deficiency causes the loss of regulation of von Willebrand factor multimeric size and platelet-tethering function, which results in the formation of disseminated microvascular platelet microthrombi. Precisely how anti-ADAMTS13 autoantibodies, or antibody subsets, cause ADAMTS13 deficiency (ADAMTS13 activity generally < 10%) has not been formally investigated. METHODS: We analysed 92 acquired TTP episodes at presentation, through treatment and remission/relapse using epitope mapping and functional analyses to understand the pathogenic mechanisms of anti-ADAMTS13 IgG. RESULTS: 89/92 of TTP episodes had IgG recognising the ADAMTS13 N-terminal domains. The central spacer domain was the only N-terminal antigenic target detected. 38/92 TTP episodes had autoantibodies recognising the N-terminal domains alone; 54/92 TTP episodes also had antibodies against the ADAMTS13 C-terminal domains (TSP2-8 and/or CUB domains). Changes in autoantibody specificity were detected in 9/16 patients at relapse, suggesting a continued development of the disease. Functional analyses on IgG from 43 patients revealed inhibitory IgG were limited to anti-spacer domain antibodies. However, 15/43 patients had autoantibodies with no detectable inhibitory action and as many as 32/43 patients had autoantibodies with inhibitory function that was insufficient to account for the severe deficiency state, suggesting that in many patients there is an alternative pathogenic mechanism. We therefore analysed plasma ADAMTS13 antigen levels in 91 acquired TTP presentation samples. We demonstrated markedly reduced ADAMTS13 antigen levels in all presentation samples, median 6% normal (range 0-47%), with 84/91 patients having < 25% ADAMTS13 antigen. ADAMTS13 antigen in the lowest quartile at first presentation was associated with increased mortality (odds ratio 5.7). CONCLUSIONS: Anti-spacer domain autoantibodies are the major inhibitory antibodies in acquired TTP. However, depletion of ADAMTS13 antigen (rather than enzyme inhibition) is a dominant pathogenic mechanism. ADAMTS13 antigen levels at presentation have prognostic significance. Taken together, our results provide new insights into the pathophysiology of acquired TTP

Balanced homodyne detectors in QFT

Within the dipole approximation we describe the interaction of a photodiode with the quantum electric field. The diode is modelled by an electron in a bound state which upon interaction, treated perturbatively in the paper, can get excited to one of the scattering states. We furthermore analyze a balanced homodyne detector (BHD) with a local oscillator (LO) consisting of two photodiodes illuminated by a monochromatic coherent state. We show, that to the leading order the BHD's output measures the expectation value of the quantum electric field, in the state without the LO, restricted to the frequency of the LO. The square of the output measures the two-point function of the quantum field. This shows that the BHDs provide tools for measurements of sub-vacuum (negative) expectation values of the squares quantum fields and thus for test of Quantum Energy Inequality - like bounds, or other QFT effects under the influence of external conditions.Comment: Revised version with minor mistakes remove

The Marine Living Resources of the Southern Ocean

The author suggests that the abundance of marine life in Antarctica presents ample opportunity both for scientific study and for exploitation. The author provides a survey of the distinct ecological system of the Southern Ocean through his discussion of the main marine species-from the simple organisms involved in primary production to the large marine mammals which have been subject to exploitation in the past. His primary emphasis is on krill, the small, shrimp-like crustacean which serves as the pivotal link in the Antarctic food chain. The abundance of krill, its high nutritive value and its ease of harvesting are factors which the author perceives as according krill significant potential for exploitation. At the same time, he identifies economic and technical obstacles which must be overcome if commercial krill harvesting is to develop