Enhancing autobiographical memory fluency & specificity: effects of eye movements & eye closure

Research has demonstrated that performing a sequence of saccadic horizontal eye movements (SEMs) prior to retrieval or closing one’s eyes during retrieval facilitates episodic memory. The research in this thesis is concerned with increasing the recall of episodic autobiographical memory in old (Experiment 1) and younger (Experiment 1-3) individuals with the use SEMs (Experiments 1-3) and eye-closure (Experiments 2-3). Experiment 1 extends previous research by examining the effects of SEMs in older and younger adults. Autobiographical episodic and semantic memory fluency was assessed in younger and older participants following saccadic (vs. fixation control) manipulations. Eye movements enhanced episodic fluency in both age groups. Semantic autobiographical memory showed a main effect of age (greater fluency in younger participants), whereas general semantic memory showed no effect of age or eye movement. Experiment 2 extended the first study by the inclusion of eye-closure. The experiment also changed how memories were elicited by use of the Galton Crovitz technique using concrete and abstract words. Recall was measured by the specificity of recall and its associated phenomenological qualities. The experiment found concrete cues to enhance both the specificity of recall and phenomenological qualities. Eye movements increased memory specificity but not phenomenological qualities. Eye closure effects were only found on the phenomenological qualities of ‘seeing’ and ‘hearing’. Experiment 3 made changes to both manipulations and measurements. Eye-closure was altered from between to within subjects and dynamic visual noise (DVN) was included to increase distraction with eyes open. As before, SEMs was manipulated between-subjects. Regarding measurements, participants indicated whether memories were recalled directly or after more effortful generation. A significant effect of eye-closure/distraction was found (except direct vs generative recall which only showed effects of DVN) showing an advantage in the eye closure condition. Cue-type produced similar findings to Experiment 2 but SEM effects produced only numerical differences. This is the first-time eye-closure and DVN effects have been shown in autobiographical memory using the cue-word technique

Saccade induced retrieval enhancement, handedness & the retrieval of central & peripheral details in eyewitness memory

Two experiments are presented that investigated the effects of horizontal saccadic eye movements and handedness on eyewitness memory for central and peripheral information. In both experiments, participants viewed a short video depicting a bank robbery and episodic memory was tested after a short delay. Experiment 1 used recognition memory and found an interaction between eye movement, handedness and type of information recalled. This indicated that eye movements enhanced memory to a greater extent for peripheral information for individuals classified as consistently handed. Experiment 2 used free-recall and found eye movement enhancement effects of similar magnitude for central and peripheral items. A similar pattern of eye movement effects was observed for both consistent and inconsistent-handed individuals. Inconsistent handers also had superior memory overall. The results are discussed in terms of theoretical accounts of eye movement effects and implications for the enhancement of eyewitness memory

Effects of saccadic eye movements on episodic & semantic memory fluency in older and younger participants

Research has demonstrated that performing a sequence of saccadic horizontal eye movements prior to retrieval facilitates performance on tests of episodic memory. This has been observed in both laboratory tasks of retention and autobiographical memory. To date, the work has centred on performance in younger individuals. This paper extends previous investigations by examining the effects of saccadic eye movements in older persons. Autobiographical episodic and semantic memory fluency was assessed in younger (age range 18-35, mean = 22.50), and older (age range 55-87, mean = 70.35) participants following saccadic (vs. fixation control) manipulations. The main effects of eye movements and age were found for episodic autobiographical memory (greater fluency after eye movements and in younger participants). Semantic autobiographical memory showed a main effect of age (greater fluency in younger participants), whereas general semantic memory showed no effect of age or eye movement. These findings indicate that saccadic horizontal eye movements can enhance episodic personal memory in older individuals. This has implications as a technique to improve autobiographical recollection in the elderly and as an adjunct in reminiscence therapy

Boron-Rich Benzene and Pyrene Derivatives for the Detection of Thermal Neutrons

A synthetic methodology is developed to generate boron rich aromatic small molecules based on benzene and pyrene moieties for the detection of thermal neutrons. The prepared aromatic compounds have a relatively high boron content up to 7.4 wt%, which is important for application in neutron detection as 10B (20% of natural abundance boron) has a large neutron induced reaction cross-section. This is demonstrated by preparing blends of the synthesized molecules with fluorescent dopants in poly(vinyltoluene) matrices resulting in comparable scintillation light output and neutron capture as state-of-the art commercial scintillators, but with the advantage of much lower cost. The boron-rich benzene and pyrene derivatives are prepared by Suzuki conditions using both microwave and traditional heating, affording yields of 40-93%. This new procedure is simple and straightforward, and has the potential to be scaled up

Non-thermal radio emission from O-type stars. IV. Cyg OB2 No. 8A

We study the non-thermal radio emission of the binary Cyg OB2 No. 8A, to see if it is variable and if that variability is locked to the orbital phase. We investigate if the synchrotron emission generated in the colliding-wind region of this binary can explain the observations and we verify that our proposed model is compatible with the X-ray data. We use both new and archive radio data from the Very Large Array (VLA) to construct a light curve as a function of orbital phase. We also present new X-ray data that allow us to improve the X-ray light curve. We develop a numerical model for the colliding-wind region and the synchrotron emission it generates. The model also includes free-free absorption and emission due to the stellar winds of both stars. In this way we construct artificial radio light curves and compare them with the observed one. The observed radio fluxes show phase-locked variability. Our model can explain this variability because the synchrotron emitting region is not completely hidden by the free-free absorption. In order to obtain a better agreement for the phases of minimum and maximum flux we need to use stellar wind parameters for the binary components which are somewhat different from typical values for single stars. We verify that the change in stellar parameters does not influence the interpretation of the X-ray light curve. Our model has trouble explaining the observed radio spectral index. This could indicate the presence of clumping or porosity in the stellar wind, which - through its influence on both the Razin effect and the free-free absorption - can considerably influence the spectral index. Non-thermal radio emitters could therefore open a valuable pathway to investigate the difficult issue of clumping in stellar winds.Comment: 19 pages, 10 figures, accepted by A&

Protein profiling in hepatocellular carcinoma by label-free quantitative proteomics in two west african populations.

Background Hepatocellular Carcinoma is the third most common cause of cancer related death worldwide, often diagnosed by measuring serum AFP; a poor performance stand-alone biomarker. With the aim of improving on this, our study focuses on plasma proteins identified by Mass Spectrometry in order to investigate and validate differences seen in the respective proteomes of controls and subjects with LC and HCC. Methods Mass Spectrometry analysis using liquid chromatography electro spray ionization quadrupole time-of-flight was conducted on 339 subjects using a pooled expression profiling approach. ELISA assays were performed on four significantly differentially expressed proteins to validate their expression profiles in subjects from the Gambia and a pilot group from Nigeria. Results from this were collated for statistical multiplexing using logistic regression analysis. Results Twenty-six proteins were identified as differentially expressed between the three subject groups. Direct measurements of four; hemopexin, alpha-1-antitrypsin, apolipoprotein A1 and complement component 3 confirmed their change in abundance in LC and HCC versus control patients. These trends were independently replicated in the pilot validation subjects from Nigeria. The statistical multiplexing of these proteins demonstrated performance comparable to or greater than ALT in identifying liver cirrhosis or carcinogenesis. This exercise also proposed preliminary cut offs with achievable sensitivity, specificity and AUC statistics greater than reported AFP averages. Conclusions The validated changes of expression in these proteins have the potential for development into high-performance tests usable in the diagnosis and or monitoring of HCC and LC patients. The identification of sustained expression trends strengthens the suggestion of these four proteins as worthy candidates for further investigation in the context of liver disease. The statistical combinations also provide a novel inroad of analyses able to propose definitive cut-offs and combinations for evaluation of performance

Manipulating ultracold atoms with a reconfigurable nanomagnetic system of domain walls

The divide between the realms of atomic-scale quantum particles and lithographically-defined nanostructures is rapidly being bridged. Hybrid quantum systems comprising ultracold gas-phase atoms and substrate-bound devices already offer exciting prospects for quantum sensors, quantum information and quantum control. Ideally, such devices should be scalable, versatile and support quantum interactions with long coherence times. Fulfilling these criteria is extremely challenging as it demands a stable and tractable interface between two disparate regimes. Here we demonstrate an architecture for atomic control based on domain walls (DWs) in planar magnetic nanowires that provides a tunable atomic interaction, manifested experimentally as the reflection of ultracold atoms from a nanowire array. We exploit the magnetic reconfigurability of the nanowires to quickly and remotely tune the interaction with high reliability. This proof-of-principle study shows the practicability of more elaborate atom chips based on magnetic nanowires being used to perform atom optics on the nanometre scale.Comment: 4 pages, 4 figure