Measurement of thrombus formation on intravascular catheters

War is a complex social situation due to the interplay of multiple factors. Economical and political ones are of utmost importance, but human attitudes and motivations must be also taken into account. Being desirable to modify human transactions in such a way that they do not interfere with the basic right of everyone to a condition of physical and mental well-being, war must be abolished. The author contends that an understanding of behaviour through Psychology can be helpful in that aim. Aggression is considered the principal psychological cause of war. It is worth while to differentiate between aggression as an instrument for attaining a special end, and as pure hostility. Only in the first form, it is held here, does it play an important role in war. Psychogists must deal also with a wide range of states of mind that can be "served" by aggression: feelings of inferiority or insecurity, fear, greed, projections, compensations, rationalizations, etc. Scientific approach is not the only one Physiology brings to war prevention. It is equally important the wide dissemination of its conclusions among the general public. Information on the dynamics that prompt people to decide war would make it easier to control. This applies not only to political or military leaders, but also to civil populations. Concerning those two possible contributions of psychologists, scientific and educative, it is suggested the extensive use of psychodramatic techniques. Their richness lie in the lifelike experiences they convey to the participants, and particular aptitude to promote changes of attitudes. Investigation and information on the psychological processes related to war should be undertaken by international organizations of social scientists, acting simultaneously in several countries. Some of the initial steps they could further: 1) that prevention of war be a current subject matter in psychological courses; 2) that the World Health Organization take interest in this subject; 3) that psychologists participate in international political and economical bodies in order to clarify the psychological factors leading to war.     

Influence of deformation history on the yield locus and stress-strain behavior of aluminum and copper

Thin-walled tubular specimens of 1100-0 aluminum and OFHC copper were loaded biaxially through the application of simultaneous axial load and internal pressure. The effects of loading path and deformation history on the stress-strain and yield locus characteristics were studied at strains less than 2.0 pct. The observed plastic strains for both materials depended on the loading path to a given stress point, whereas the loading path during prestraining did not affect subsequent deformation. Deformation subsequent to prestraining depended on the prestraining magnitude and direction at strains less than 0.2 pct and only on the magnitude at larger strains. The resulting plastic response was, therefore, anisotropic at small strains and isotropic at large strains. The small strain behavior cannot be predicted by present continuum plasticity theories, whereas the large strain behavior agrees with the isotropic hardening rule. It was also found that a prestraining operation of sufficient plastic strain can erase some of the prior deformation history. Formerly with the Los Alamos Scientific Laboratory, Los Alamos, N. M.     

A flexible method for the conjugation of aminooxy ligands to preformed complexes of nucleic acids and lipids

Attachment of targeted ligands to nonviral DNA or RNA delivery systems is a promising strategy that seeks to overcome the poor target selectivity generally observed in systemic delivery applications. Several methods have been developed for the conjugation of ligands to lipids or polymers, however, direct conjugation of ligands onto lipid- or polymer-nucleic acid complexes is not as straightforward. Here, we examine an oximation approach to directly label a lipoplex formulation. Specifically, we report the synthesis of a cationic diketo lipid DMDK, and its use as a convenient ligation tool for attachment of aminooxy-functionalized reagents after its complexation with DNA. We demonstrate the feasibility of direct lipoplex labeling by attaching an aminooxy-functionalized fluorescent probe onto pre-formed plasmid DNA-DMDK lipoplexes (luciferase, GFP). The results reveal that DMDK protects DNA from degradation on exposure to either DNase or human cerebral spinal fluid, and that simple mixing of DMDK lipoplexes with the aminooxy probe labels the complexes without sacrificing transfection efficiency. The biocompatibility and selectivity of this method, as well as the ease of bioconjugation, make this labeling approach ideal for biological applications.     

Theory for saturation stress difference in torsion versus other types of deformation at low temperatures

Torsion tests carried out to large plastic strains typically exhibit a leveling out (saturation) of the flow stress. On the other hand, saturation is usually not observed for other modes of deformation such as wire drawing or rolling. In iron and other body-centered cubic materials linear hardening persists to strains of $\text{≈ 10}$. For face-centered cubic materials the behavior is mixed, with saturation not being achieved for most impure metals. We propose an explanation for the difference in flow stress at large strains between torsion and other modes of deformation. The explanation is based on Holt's dislocation cell wall formation theory and on the fact that apparently dislocations of only one Burgers vector are required to be active in torsion at large strains, whereas several are required for other deformation modes. Consequently, at the same dislocation density and applied stress level dislocations of opposite character but of the same kind are closer together in torsion. The dislocations have a stronger force of attraction between them and a faster rate of mutual annihilation through pipe diffusion controlled climb. The saturation stress is larger the larger is the number of different Burgers vectors of the dislocations involved in the deformation. Shear band instabilities are explained as a consequence of material locally reducing the number of active slip systems.     

How Do Logical Inference Rules Help Construct Social Mental Models?

Starting from recent approaches in mental model research, it is argued that (1) logical inference rules are used in order to construct mental cliques from learned sentiment relations, and (2) social context cues (operationalized as primes) play a crucial role in activating such rules. Transitivity and antitransitivity are taken as examples, and are shown as core constituents of such models. In a first experiment, priming was achieved by announcing the sorting of fictitious persons in either two or three cliques. Thirty-one subjects studied eight sets of sentiment relations among these persons that either did or did not satisfy their primed clique expectations. They showed longer study times and more requests for additional information in the case of inconsistent fits between prime and set. Their sorting solutions also showed clear priming effects. A second experiment (n = 30) showed that when undergoing a recognition test after seeing the relation sets, subjects tended to confuse model-consistent distractors with information they had actually seen. In a third experiment (n = 30) the results from Experiment 1 were replicated using more realistic learning materials.     

Leveraging federal research and development for united states science and technology

Summary The United States continues to depend heavily on science and technology for ensuring its defense needs, promoting human welfare, and enhancing its economic competitiveness. I hope that my comments have helped to reinforce the point that we, as a nation, must do a better job of leveraging the federal investment in R & D. I have used examples in materials science and engineering to illustrate how this can be done, because materials science and engineering are crucial to our security and competitiveness, as pointed out in the National Research Council’s report. I also took the liberty of telling you about the broad diversity of the materials program at Los Alamos by picking my examples from Los Alamos’ work. In closing, I recognize fully that what I have discussed today is only part of what is required to maintain national security and enhance competitiveness. I believe that, first and foremost, we must get United States industry back into the lead. And the United States government must address the macroeconomic issues and deal with the crisis in education as well. But I also believe that Los Alamos can help in leveraging the federal R & D investment.