Distraction in Verbal Short-Term Memory: Insights from Developmental Differences

The contribution of two mechanisms of auditory distraction in verbal serial short-term memory—interference with the serial rehearsal processes used to support short-term recall and general attentional diversion—was investigated by exploiting differences in auditory distraction in children and adults. Experiment 1 showed that serial rehearsal plays a role in children’s as well as adults’ distractibility: Auditory distraction from irrelevant speech was greater for both children and adults as the burden on rehearsal increased. This pattern was particularly pronounced in children, suggesting that underdeveloped rehearsal skill in this population may increase their distractibility. Experiment 2 showed that both groups were more susceptible to changing- than steady-state speech when the task involved serial rehearsal—indicating that both groups suffer interference-by-process—but that children, but not adults, were also susceptible to any sort of sound (steady or changing) in a task thought to be devoid of serial rehearsal. The overall pattern of results suggests that children’s increased susceptibility to auditory distraction during verbal short-term memory performance is due to a greater susceptibility to attentional diversion; in this view, under-developed rehearsal-skill increases children’s distractibility by exacerbating their under-developed attentional control rather than by increasing interference-by-process

Enhanced gain and output power of a sealed‐off rf‐excited CO2 waveguide laser with gold‐plated electrodes

The small‐signal gain and the laser output power have been measured in a cw sealed‐off rf‐excited CO2waveguide laser for two different electrodematerials, gold‐plated copper and aluminum, at several excitation frequencies, gas pressures and mixture compositions. In the case of the gold‐plated electrodes an enhancement of the gain up to a factor of 2 and the output power up to a factor of 1.4 with time at a frequency of 190 MHz and 60 Torr of 1:1:5+5% (CO2:N2:He+Xe) mixture is observed. This is believed to be the result of the goldcatalytic activities which are favored by increased electrode temperatures and helium rich gas compositions

Predictors of longitudinal change in bone mineral density in a cohort of HIV-positive and negative subjects.

OBJECTIVE: Although low bone mineral density (BMD) is prevalent in HIV, changes in BMD over time remain unclear. We aimed to compare rates of, and factors associated with, BMD change between HIV-positive and HIV-negative subjects. METHODS: In a prospective, 3-year cohort, HIV-positive and HIV-negative subjects provided annual demographic and clinical data, fasting bloods and dual x-ray absorptiometry (DXA). Using longitudinal mixed models we compared and determined predictors of rate of change in BMD. RESULTS: Of 384 subjects (45.8% HIV-positive), 120 contributed two and 264 contributed three BMD measurements. Those with HIV were younger (median (IQR) 39 (34-46) vs 43 (35-50) years; p=0.04), more often male (61% vs 46%; p = 0.003) and less likely Caucasian (61% vs 82%; p 30 years, Caucasian ethnicity, and not being on ART during follow-up were associated with greater decline and higher parathyroid hormone associated with a smaller decline in BMD at the femoral neck. We found no association between BMD change and exposure to tenofovir disoproxil fumarate or protease inhibitors. CONCLUSIONS: We observed no difference in rate of BMD decline regardless of HIV status and in HIV positive subject, having started ART within the previous three months was the only factor associated with greater BMD decline at all 3 sites

Becoming an English language teacher:linguistic knowledge, anxieties and the shifting sense of identity

English Language is a fast growing and popular subject at A level but the majority of qualified secondary teachers in the UK have subject expertise and backgrounds in literature. This paper reports on interviews with seven secondary English teachers who discuss the strategies they used when taking on the responsibility of A level English Language teaching for the first time. It highlights the shifting sense of identity that these teachers felt they went through, and as such, explores some emerging issues related to identity from a narrative/personal history perspective. The study reveals that despite feelings of anxiety and low self-confidence, teachers felt that the experience had been a positive one in terms of their own developing identity as an English teacher and had impacted on other aspects of their teaching. The paper raises questions about the value of language-based work for English teachers and has implications for UK initial and continuing teacher education in English

Elimination of the word length effect by irrelevant sound revisited

The word length effect refers to the tendency for lists of long words to be recalled less well than lists of short words. Theoretical and empirical objections are raised to a recent claim that irrelevant speech eliminates the word length effect (Neath, Suprenant, & LeCompte, 1998). A first experiment using a within-subjects design of adequate power (N = 65) fails to replicate their finding, showing instead that the word length effect is not differentially eliminated by speech as opposed to tones. In a second experiment, the effect of change (repeated vs. changing sounds) is shown to be additive to the effect of word length for both speech and nonspeech. Irrelevant speech and irrelevant tones have comparable effects on lists of short or lists of long words. These results are at variance with the feature model (e.g., Nairne, 1990)

Greene SCPrimer: a rapid comprehensive tool for designing degenerate primers from multiple sequence alignments

Polymerase chain reaction (PCR) is widely applied in clinical and environmental microbiology. Primer design is key to the development of successful assays and is often performed manually by using multiple nucleic acid alignments. Few public software tools exist that allow comprehensive design of degenerate primers for large groups of related targets based on complex multiple sequence alignments. Here we present a method for designing such primers based on tree building followed by application of a set covering algorithm, and demonstrate its utility in compiling Multiplex PCR primer panels for detection and differentiation of viral pathogens

Changing Selective Pressure during Antigenic Changes in Human Influenza H3

The rapid evolution of influenza viruses presents difficulties in maintaining the optimal efficiency of vaccines. Amino acid substitutions result in antigenic drift, a process whereby antisera raised in response to one virus have reduced effectiveness against future viruses. Interestingly, while amino acid substitutions occur at a relatively constant rate, the antigenic properties of H3 move in a discontinuous, step-wise manner. It is not clear why this punctuated evolution occurs, whether this represents simply the fact that some substitutions affect these properties more than others, or if this is indicative of a changing relationship between the virus and the host. In addition, the role of changing glycosylation of the haemagglutinin in these shifts in antigenic properties is unknown. We analysed the antigenic drift of HA1 from human influenza H3 using a model of sequence change that allows for variation in selective pressure at different locations in the sequence, as well as at different parts of the phylogenetic tree. We detect significant changes in selective pressure that occur preferentially during major changes in antigenic properties. Despite the large increase in glycosylation during the past 40 years, changes in glycosylation did not correlate either with changes in antigenic properties or with significantly more rapid changes in selective pressure. The locations that undergo changes in selective pressure are largely in places undergoing adaptive evolution, in antigenic locations, and in locations or near locations undergoing substitutions that characterise the change in antigenicity of the virus. Our results suggest that the relationship of the virus to the host changes with time, with the shifts in antigenic properties representing changes in this relationship. This suggests that the virus and host immune system are evolving different methods to counter each other. While we are able to characterise the rapid increase in glycosylation of the haemagglutinin during time in human influenza H3, an increase not present in influenza in birds, this increase seems unrelated to the observed changes in antigenic properties