The Renormalization-Group Method Applied to Asymptotic Analysis of Vector Fields

The renormalization group method of Goldenfeld, Oono and their collaborators is applied to asymptotic analysis of vector fields. The method is formulated on the basis of the theory of envelopes, as was done for scalar fields. This formulation actually completes the discussion of the previous work for scalar equations. It is shown in a generic way that the method applied to equations with a bifurcation leads to the Landau-Stuart and the (time-dependent) Ginzburg-Landau equations. It is confirmed that this method is actually a powerful theory for the reduction of the dynamics as the reductive perturbation method is. Some examples for ordinary diferential equations, such as the forced Duffing, the Lotka-Volterra and the Lorenz equations, are worked out in this method: The time evolution of the solution of the Lotka-Volterra equation is explicitly given, while the center manifolds of the Lorenz equation are constructed in a simple way in the RG method.Comment: The revised version of RYUTHP 96/1. Submitted to Prog. Theor. Phys. (Kyoto) in Feb., 1996. 28 pages. LATEX. No figure

Flow cytometric evaluation of red blood cells transformed with variable amounts of synthetic A and B glycolipids

Background: According to national guidelines or directives, monoclonal ABO reagents may be required to detect Ax and B weak subgroup red blood cells (RBCs). Many routine laboratories do not have access to naturallyoccurring ABO subgroups that can be used as weak controls for these reagents. Group O RBCs modified with synthetic analogs of blood group A and/or B glycolipids (KODE technology) to mimic weak ABO subgroups could be used for quality control purposes. Aim: Extensive serological testing of KODE RBCs has previously been performed. An extended evaluation of KODE RBCs using flow cytometry was performed to explore the correlation between the concentrations of synthetic glycolipids and A/B site density of the resulting RBCs. The aim of this study was to examine if KODE RBCs mimic the distinct flow cytometric patterns of naturally-occurring ABO subgroups. Material and Methods: KODE RBCs were prepared according to a previously decribed procedure [Frame et al., Transfusion 2007; 47: 876–82]. RBCs were modified with 15 different concentrations of synthetic glycolipids, ranging from 1 mg/mL to 60 ng/mL for KODE-A and 5 mg/mL to 0.3 lg/mL for KODE-B. The concentration was decreased by doubling dilution steps. Sensitive and specific flow cytometry [Hult & Olsson. Transfusion 2006; 9S: 32A] was used to characterize and semiquantify the synthetic A and B antigen levels on RBCs. Relevant control RBCs (A1, A2, Ax, B, Bweak and O) were included in each run. For both KODE-A and KODE-B RBCs, repeat samples were produced for four selected concentrations and all KODE batches were tested in triplicate. Results: Flow cytometric testing of KODE RBCs modified with high concentrations of synthetic glycolipids revealed a uniform and even distribution of antigens in the cell population as shown by a single narrow peak in the FACS histograms. When lower concentrations were used, peaks tended to broaden to a pattern found in Ax and most B subgroups indicating a more variable antigen site density on the cells in the population. The concentrations of synthetic glycolipids that produced KODE cells that resembled the naturally-occurring subgroup control RBCs used in this study are ~2–4 lg/mL for KODE-A and ~10 lg/mL for KODEB. Repeat testing demonstrated good correlation between flow cytometric runs. Discussion and Conclusion: Using very low amounts of synthetic glycolipids, KODE-A and KODE-B RBCs can be made to mimic Ax and Bweak subgroup control RBCs, respectively, according to this flow cytometry method. With higher concentrations of synthetic glycolipids, the KODE RBCs demonstrated a more uniform and even distribution of antigens among the cells. This is in contrast to naturally-occurring subgroups in which some cells express almost no A or B antigen whilst others have close to normal levels. The reason for this is unknown. KODE RBCs obviously lack A carrying glycoproteins but it is not fully understood to what extent glycolipid versus glycoprotein epitopes contribute to the phenotype of weak subgroups. This study indicates that KODE RBCs with weak expression of A and/or B antigen have characteristics compatible with use as quality controls for monoclonal ABO reagents and could be a valuable addition in the serological laboratory

Failure to learn from feedback underlies word learning difficulties in toddlers at risk for autism

Children’s assignment of novel words to nameless objects, over objects whose names they know (mutual exclusivity; ME) has been described as a driving force for vocabulary acquisition. Despite their ability to use ME to fast-map words (Preissler & Carey, 2005), children with autism show impaired language acquisition. We aimed to address this puzzle by building on studies showing that correct referent selection using ME does not lead to word learning unless ostensive feedback is provided on the child’s object choice (Horst & Samuelson, 2008). We found that although toddlers aged 2;0 at risk for autism can use ME to choose the correct referent of a word, they do not benefit from feedback for long-term retention of the word–object mapping. Further, their difficulty using feedback is associated with their smaller receptive vocabularies. We propose that difficulties learning from social feedback, not lexical principles, limits vocabulary building during development in children at risk for autism

Does a measure of adaptive performance predict in-basket performance?

The ability for employees to adapt to a given situation is critical for organizations hoping to remain successful in today’s turbulent environment. For law enforcement officers, adapting to a situation is even more critical since this can be the difference between life or death. In an effort to assist law enforcement in promoting personnel with the adaptive performance (AP) skill required to be effective, this study examines the relationship between AP and an individual’s performance on an in-basket assessment. The study found that AP significantly predicts in-basket performance when rank is considered

Exploring the Feasibility of Assessing Cultural Competence in Police Officers

Pathology, personality, and integrity-related construct assessments have been widely used in the selection of police officers. However, the incidence of police brutality and misconduct is still concerning. The present study explored the feasibility of the assessment of cultural competence in police officers. We explored the extent to which the change to the agency’s first ever Black CEO would affect cultural competence of the officers as well as incidence of misconduct. Results showed that scores on a cultural competence factor of an in-basket simulation used for promotional assessments at a state highway patrol agency were not predictive of either supervisor-rated performance or incidence of misconduct. Whereas results showed that misconduct was not predicted by the agency’s first Black CEO, cultural competence of the officers did increase after the change in command. Practical implications for law enforcement agencies and suggestions for future research are discussed

Retesting in a promotional process: Amount of time between tests accounting for magnitude of score increases

There are many reasons why an applicant may retake a selection test, whether it’s due to reasons outside of their control or perhaps their first test administration was unsuccessful. Research has shown that scores generally increase when applicants retake a test. However, research on situational judgment tests and in-basket simulations have been overshadowed by research on admissions tests, cognitive ability tests, and personality tests. Further, much research has focused on retesting effects during the initial selection process, but the current research aims to shed light on retesting effects during the promotional process. The literature shows conflicting findings regarding time between tests. While some literature says that more time between tests results in larger score increases, other research says that less time between tests results in larger score increases. The current study aims to clarify this conflicting history of research while closing the gap on types of assessments examined in the retesting literature. Results showed that more time between tests resulted in larger score gains for both the SJT and in the in-basket simulation. This is probably due to the nature of the test. SJTs and In-Baskets require a lot of job knowledge. Having more time on the job between tests would allow candidates to learn more and apply that on their second attempt at promotion. The literature on time between supports this notion. Studies that showed less time between tests resulted in larger score increases were assessing some aspect of cognitive ability. Perhaps for other tests less time between tests allows for greater score increases, but for job knowledge tests, more time between tests allows for these greater score increases. Practical implications and areas for future research are discussed. Keywords: retesting, promotion, in-basket, situational judgment tes