The effect of aluminium coating on elemental standards in X-ray microanalysis

The standardisation of frozen hydrated bulk biological specimens using gelatin standards is described. The relationship between corrected elemental X-ray counts and ionic concentration was found to be linear, and minimum detectable limits for each element are stated. Variations in uncorrected standard curves were found to be due to changes in aluminium coating thickness. There was an inverse relationship between coating thickness and elemental X-ray counts. The factors causing this are discussed. To avoid errors arising from inconsistent aluminium thickness, experimental material should only be compared with standards of similar aluminium net counts. This can be achieved most easily by mounting and analysing specimen and standard together.     

Risky Business: Why People Feel Safe in Sexually Expicit On-Line Communication

The purpose of this study was to assess the use, in computer-mediated communication, of the strategic message structuring tactic known as framing. Interlocutors in computer-mediated environments have software supported systemic resources facilitative of constructing messages using framing tactics in their argumentative discourse. It is hypothesized that framing strategies are related to the emotional tenor of a disputant's message and that a speaker's emotional involvement with an issue should be curvilinearly related to the appropriation of framing as an argumentative discourse strategy. Results from the analysis of 3000 messages, obtained from a diverse sampling of computer-mediated discussion groups and forums, provided support for the primary hypothesized relationship. A speaker's emotional involvement was significantly and curvilinearly related to two message framing devices (message dependency and coalition building) and a measure of conciliatory face-saving moves.     

A time domain approach for avoiding crosstalk in optical blockingmultistage interconnection networks

Crosstalk in multistage interconnection networks can be avoided by ensuring that a switch is not used by two connections simultaneously, in order to support crosstalk-free communications among N inputs and N outputs, a space domain approach dilates an N×N network into one that is essentially equivalent to a 2N×2N network. Path conflicts, however may still exist in dilated networks. This paper proposes a time domain approach for avoiding crosstalk. Such an approach can be regarded as “dilating” a network in time, instead of space. More specifically, the connections that need to use the same switch are established during different time slots. This way, path conflicts are automatically avoided. The time domain dilation is useful for overcoming the limits on the network size while utilizing the high bandwidth of optical interconnects. We study the set of permutations whose crosstalk-free connections can be established in just two time slots using the time domain approach. While the space domain approach trades hardware complexity for crosstalk-free communications, the time domain approach trades time complexity. We compare the proposed time domain to the space domain approach by analyzing the tradeoffs involved in these two approaches     

Chiroptical activity of holmium pyrogermanate: tetragonal Ho2Ge2O7

Chiroptical luminescence and circular dichroism measurements are reported for single crystals of Ho₂Ge₂O₇. These crystals belong to the tetragonal space group P4,2,2 (or P4₃2₁2) with Z=4. Each Ho³⁺ ion in the crystal structure is coordinated to seven oxygens to form a distorted pentagonal bipyramid. The Ho³⁺ ions exhibit luminescence from several excited multiplet levels; chiroptical luminescence spectra are reported for ⁶I₈ → ⁶F₆, ⁶S₂, and ⁶F₃ at a sample temperature of 10 K. Room-temperature absorption and circular dichroism measurements are reported for the ⁶I₈ → ⁶F₆, ⁵S₂, ⁶F₄, and ⁶F₃ transition regions.     

Application of parallelized analogical planning to engineering design

Analogical planning provides a means of solving engineering problems where other machine learning methods fail. Unlike many machine learning paradigms, analogy does not require numerous previous examples or a rich domain theory. Instead, analogical planners adapt knowledge of solved problems in similar domains to the current problem. Unfortunately, the analogical planning task is an expensive one. While the process of forming correspondences between a known problem and a new problem is complex, the problem of selecting a base case for the analogy is virtually intractable.This paper addresses the issue of efficiently forming analogical plans. The Anagram planning system is described, which takes advantage of the massively parallel architecture of the Connection Machine to perform base selection and map formation. Anagram provides a tractable solution to analogical planning, with a complexity that is sublinear in the size of the plans.This paper describes the Anagram system and its parallel algorithms. The paper also presents theoretical analyses and empirical results of testing the system on a large database of plans from the domain of automatic programming.     

Teaching critical thinking for transfer across domains: Disposition, skills, structure training, and metacognitive monitoring.

Advances in technology and changes in necessary workplace skills have made the ability to think critically more important than ever before, yet there is ample evidence that many adults consistently engage in flawed thinking. Numerous studies have shown that critical thinking, defined as the deliberate use of skills and strategies that increase the probability of a desirable outcome, can be learned in ways that promote transfer to novel contexts. A 4-part empirically based model is proposed to guide teaching and learning for critical thinking: (a) a dispositional component to prepare learners for effortful cognitive work, (b) instruction in the skills of critical thinking, (c) training in the structural aspects of problems and arguments to promote transcontextual transfer of critical-thinking skills, and (d) a metacognitive component that includes checking for accuracy and monitoring progress toward the goal. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Sex-identifying urine and molt signals in lobster (Homarus americanus)

During courtship, premolt female lobsters,Homarus americanus, choose a male and initiate a pair bond by repeated approaches to his shelter. The male allows such a female to share his shelter for about one week. This knowledge formed the basis to search for quantitative evidence for lobster sex pheromone(s) used in courtship: male cues to allow premolt females to identify a preferred male, and female cues to allow males to identify a premolt mature female. In each of four 1500-liter naturalistic aquaria, the behavioral responses of one female and two male lobsters to male and female lobster urine (0.5 ml) and body odor (20 ml) stimuli were observed. These stimuli were injected once or twice per day into a continuously flowing delivery tube attached to lobster shelters. Habituation to stimulus introduction—a serious problem in earlier experiments—was apparently avoided in the more natural social and physical environment we employed in these experiments. We demonstrated that male and female molt body odors contain different chemical substances: females responded to male molt body odor and males responded to female molt body odor but not vice versa. In general, male and female intermolt urine caused strong responses; however, females responded only weakly to male urine. This suggests that male and female urine are chemically different. Female urine and molt body odor caused a typically male high-on-legs response. These results show that molt body odors and intermolt urine contain sex-specific substances, which may be used in lobster courtship as well as other social interactions.     

Immunoglobulin 1 (IgG1) Fc-glycosylation profiling of anti-citrullinated peptide antibodies from human serum

In several autoimmune disorders, including rheumatoid arthritis (RA), autoantibodies are thought to be the driving force of pathogenicity. Glycosylation of the Fc-part of human Igs is known to modulate biological activity. Hitherto, glycosylation of human IgG-Fc has been analyzed predominantly at the level of total serum IgG, revealing reduced galactosylation in RA. Given the pathogenic relevance of autoantibodies in RA, we wished, in the present study, to address the question whether distinct Fc-glycosylation features are observable at the level of antigen-specific IgG subpopulations. For this purpose, we have developed a method for the microscale purification and Fc-glycosylation analysis of anti-citrullinated peptide antibodies (ACPA). ACPA represent a group of autoantibodies that occur with unique specificity in RA patients. Their presence is associated with increased inflammatory disease activity and rapid joint destruction. Results indicate that ACPA of the IgG1 subclass vary considerably from total serum IgG1 with respect to Fc-galactosylation, with galactosylation being higher on ACPA than on serum IgG1 for some patients, while other patients show higher galactosylation on serum IgG1 than on ACPA. Using this method, studies can be performed on the biological and clinical relevance of ACPA glycosylation within RA patient cohorts.     

Flow simulations in arbitrarily complex cardiovascular anatomies – An unstructured Cartesian grid approach

Image guided computational fluid dynamics is attracting increasing attention as a tool for refining in vivo flow measurements or predicting the outcome of different surgical scenarios. Sharp interface Cartesian/Immersed-Boundary methods constitute an attractive option for handling complex in vivo geometries but their capability to carry out fine-mesh simulations in the branching, multi-vessel configurations typically encountered in cardiovascular anatomies or pulmonary airways has yet to be demonstrated. A major computational challenge stems from the fact that when such a complex geometry is immersed in a rectangular Cartesian box the excessively large number of grid nodes in the exterior of the flow domain imposes an unnecessary burden on both memory and computational overhead of the Cartesian solver without enhancing the numerical resolution in the region of interest. For many anatomies, this added burden could be large enough to render comprehensive mesh refinement studies impossible. To remedy this situation, we recast the original structured Cartesian formulation of Gilmanov and Sotiropoulos [Gilmanov A, Sotiropoulos F. A hybrid Cartesian/immersed boundary method for simulating flows with 3D, geometrically complex, moving bodies. J Comput Phys 2005;207(2):457–92] into an unstructured Cartesian grid layout. This simple yet powerful approach retains the simplicity and computational efficiency of a Cartesian grid solver, while drastically reducing its memory footprint. The method is applied to carry out systematic mesh refinement studies for several internal flow problems ranging in complexity from flow in a 90° pipe bend to flow in an actual, patient-specific anatomy reconstructed from magnetic resonance images. Finally, we tackle the challenging clinical scenario of a single-ventricle patient with severe arterio-venous malformations, seeking to provide a fluid dynamics prospective on a clinical problem and suggestions for procedure improvements. Results from these simulations demonstrate very complex cardiovascular flow dynamics and underscore the need for high-resolution simulations prior to drawing any clinical recommendations.