Memory for emotional faces in major depression following judgement of physical facial characteristics at encoding

The aim of the present study was to establish if patients with major depression (MD) exhibit a memory bias for sad faces, relative to happy and neutral, when the affective element of the faces is not explicitly processed at encoding. To this end, 16 psychiatric out-patients with MD and 18 healthy, never-depressed controls (HC) were presented with a series of emotional faces and were required to identify the gender of the individuals featured in the photographs. Participants were subsequently given a recognition memory test for these faces. At encoding, patients with MD exhibited a non-significant tendency towards slower gender identification (GI) times, relative to HC, for happy faces. However, the GI times of the two groups did not differ for sad or neutral faces. At memory testing, patients with MD did not exhibit the expected memory bias for sad faces. Similarly, HC did not demonstrate enhanced memory for happy faces. Overall, patients with MD were impaired in their memory for the faces relative to the HC. The current findings are consistent with the proposal that mood-congruent memory biases are contingent upon explicit processing of the emotional element of the to-be-remembered material at encoding.

Flexibility of short-strand RNA in aqueous solution as revealed by molecular dynamics simulation:are A′-RNA and A-RNA distinct conformational structures?

We use molecular dynamics simulations to compare the conformational structure and dynamics of a 21-base pair RNA sequence initially constructed according to the canonical A-RNA and A'-RNA forms in the presence of counterions and explicit water. Our study aims to add a dynamical perspective to the solid-state structural information that has been derived from X-ray data for these two characteristic forms of RNA. Analysis of the three main structural descriptors commonly used to differentiate between the two forms of RNA namely major groove width, inclination and the number of base pairs in a helical twist over a 30 ns simulation period reveals a flexible structure in aqueous solution with fluctuations in the values of these structural parameters encompassing the range between the two crystal forms and more. This provides evidence to suggest that the identification of distinct A-RNA and A'-RNA structures, while relevant in the crystalline form, may not be generally relevant in the context of RNA in the aqueous phase. The apparent structural flexibility observed in our simulations is likely to bear ramifications for the interactions of RNA with biological molecules (e.g. proteins) and non-biological molecules (e.g. non-viral gene delivery vectors). © CSIRO 2009.

Capabilities for strategic flexibility:a cognitive content framework

Different forms of strategic flexibility allow for reactive adaptation to different changing environments and the proactive driving of change. It is therefore becoming increasingly important for decision makers to not only possess marketing capabilities, but also the capabilities for strategic flexibility in its various forms. However, our knowledge of the relationships between decision makers’ different ways of thinking and their capabilities for strategic flexibility is limited. This limitation is constraining research and understanding. In this article we develop a theoretical cognitive content framework that postulates relationships between different ways of thinking about strategy and different information-processing demands. We then outline how the contrasting beliefs of decision makers may influence their capabilities to generate different hybrid forms of strategic flexibility at the cognitive level. Theoretically, the framework is embedded in resource-based theory, personal construct theory and schema theory. The implications for research and theory are discussed.

A qualitative investigation into leader behavioural flexibility

Purpose – The current research aims to determine to what extent Australian managers are behaviourally flexible and to identify what factors are associated with the development of leader behavioural flexibility (LBF) and its contribution to positive organisational outcomes. Design/methodology/approach – Because of the exploratory nature of the questions to be addressed, a qualitative approach to data collection was selected. In particular, the grounded theory methodology was utilised due to its ability to aid with the theory building process. Semi-structured interviews based on the critical incident interview technique were used as the data source. Findings – The findings illustrate that the Australian managers who participated in this study exhibited significant degrees of LBF. The results also suggest that education level and group size may be antecedents to LBF. In addition, it appears that leader-member exchange may mediate the relationship between LBF and positive organisational outcomes, while social intelligence may moderate this relationship. Research limitations/implications – The current research makes several contributions in terms of theoretical development and reveals a richer insight into the underlying processes associated with the relationship between LBF and positive organisational outcomes. Practical implications – As the current research was conducted in the field with 20 practising organisational managers, the findings also highlight some important practical applications regarding LBF. Originality/value – Although previous studies have been able to establish a relationship between LBF and positive organisational outcomes, they have explained very little about the processes associated with this relationship. The present study attempted to uncover some of these processes.

Microprocessor simulation of speech-encoding

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Low bit-rate speech encoding for digital mobile radio

The need for low bit-rate speech coding is the result of growing demand on the available radio bandwidth for mobile communications both for military purposes and for the public sector. To meet this growing demand it is required that the available bandwidth be utilized in the most economic way to accommodate more services. Two low bit-rate speech coders have been built and tested in this project. The two coders combine predictive coding with delta modulation, a property which enables them to achieve simultaneously the low bit-rate and good speech quality requirements. To enhance their efficiency, the predictor coefficients and the quantizer step size are updated periodically in each coder. This enables the coders to keep up with changes in the characteristics of the speech signal with time and with changes in the dynamic range of the speech waveform. However, the two coders differ in the method of updating their predictor coefficients. One updates the coefficients once every one hundred sampling periods and extracts the coefficients from input speech samples. This is known in this project as the Forward Adaptive Coder. Since the coefficients are extracted from input speech samples, these must be transmitted to the receiver to reconstruct the transmitted speech sample, thus adding to the transmission bit rate. The other updates its coefficients every sampling period, based on information of output data. This coder is known as the Backward Adaptive Coder. Results of subjective tests showed both coders to be reasonably robust to quantization noise. Both were graded quite good, with the Forward Adaptive performing slightly better, but with a slightly higher transmission bit rate for the same speech quality, than its Backward counterpart. The coders yielded acceptable speech quality of 9.6kbps for the Forward Adaptive and 8kbps for the Backward Adaptive.

Cloning, mapping and identification of the Aeromonas salmonicida fstA, fepA and irpA genes, encoding the 86, 82 and 74 kDa iron-regulated outer membrane proteins, respectively

Three iromps (iron-regulated outer membrane proteins) of Aeromonas salmonicida were identified by the use of specific antibodies together with Southern hybridization analysis and limited nucleotide sequencing of their genes. The results of these experiments together with a search of the international database for homologous sequences led to their identification as follows: -86 kDa iromp (FstA) as a Vibrio anguillarum Fat A homologue -82 kDa iromp (FepA) as an Escherichia coli FepA homologue -74 kDa iromp (IrpA) as an Escherichia coli Cir homologue.

Synthesis and expression of a gene encoding a 48-residue repeat in the Pseudomonas syringae ice nucleation protein

The aim of this work was to construct short analogues of the repetitive water-binding domain of the Pseudomonas syringae ice nucleation protein, InaZ. Structural analysis of these analogues might provide data pertaining to the protein-water contacts that underlie ice nucleation. An artificial gene coding for a 48-mer repeat sequence from InaZ was synthesized from four oligodeoxyribonucleotides and ligated into the expression vector, pGEX2T. The recombinant vector was cloned in Escherichia coli and a glutathione S-transferase fusion protein obtained. This fusion protein displayed a low level of ice-nucleating activity when tested by a droplet freezing assay. The fusion protein could be cleaved with thrombin, providing a means for future recovery of the 48-mer peptide in amounts suitable for structural analysis by nuclear magnetic resonance spectroscopy.

The effect of inversion on the encoding of normal and “thatcherized” faces

In the "Thatcher illusion" a face, in which the eyes and mouth are inverted relative to the rest of the face, looks grotesque when shown upright but not when inverted. In four experiments we investigated the contribution of local and global processing to this illusion in normal observers. We examined inversion effects (i.e., better performance for upright than for inverted faces) in a task requiring discrimination of whether faces were or were not "thatcherized". Observers made same/different judgements to isolated face parts (Experiments 1-2) and to whole faces (Experiments 3-4). Face pairs had the same or different identity, allowing for different processing strategies using feature-based or configural information, respectively. In Experiment 1, feature-based matching of same-person face parts yielded only a small inversion effect for normal face parts. However, when feature-based matching was prevented by using the face parts of different people on all trials (Experiment 2) an inversion effect occurred for normal but not for thatcherized parts. In Experiments 3 and 4, inversion effects occurred with normal but not with thatcherized whole faces, on both same- and different-person matching tasks. This suggests that a common configural strategy was used with whole (normal) faces. Face context facilitated attention to misoriented parts in same-person but not in different-person matching. The results indicate that (1) face inversion disrupts local configural processing, but not the processing of image features, and (2) thatcherization disrupts local configural processing in upright faces.

A computational model of prosody for Yorùbá text-to-speech synthesis

This work examines prosody modelling for the Standard Yorùbá (SY) language in the context of computer text-to-speech synthesis applications. The thesis of this research is that it is possible to develop a practical prosody model by using appropriate computational tools and techniques which combines acoustic data with an encoding of the phonological and phonetic knowledge provided by experts. Our prosody model is conceptualised around a modular holistic framework. The framework is implemented using the Relational Tree (R-Tree) techniques (Ehrich and Foith, 1976). R-Tree is a sophisticated data structure that provides a multi-dimensional description of a waveform. A Skeletal Tree (S-Tree) is first generated using algorithms based on the tone phonological rules of SY. Subsequent steps update the S-Tree by computing the numerical values of the prosody dimensions. To implement the intonation dimension, fuzzy control rules where developed based on data from native speakers of Yorùbá. The Classification And Regression Tree (CART) and the Fuzzy Decision Tree (FDT) techniques were tested in modelling the duration dimension. The FDT was selected based on its better performance. An important feature of our R-Tree framework is its flexibility in that it facilitates the independent implementation of the different dimensions of prosody, i.e. duration and intonation, using different techniques and their subsequent integration. Our approach provides us with a flexible and extendible model that can also be used to implement, study and explain the theory behind aspects of the phenomena observed in speech prosody.

Organisational slack resources, the definitions and consequences for business flexibility and performance : an empirical investigation

Slack resources are recognised to be those spare capabilities and assets of the organisation that are variable reclaimable for re-deployment. They represent under utilised and hidden spare energies within a company that may be recaptured and employed for a variety of tasks. However their positive contribution to organisational success has been a contentious claim that has provoked the intuitive argument that slack resources are inefficiency and are to be eradicated. The counter argument has been that very efficient organisations are inflexible and therefore incapable of being responsive to an increasingly dynamic environment. Therefore this work compares and contrasts three distinctive industries in a holistic manner and maps the impact of environmental flux on the firm, its subsequent disruptive ripples through the organisation and its absorption by slack resources. Through this process it is demonstrated that slack resources do positively contribute to organisational performance and subsequently the ability of slack to promote sustained competitive advantage is also identified. The major findings of this work are listed. 1. This work has developed and perfected a new research model that aids the investigation of the internal behaviours and consequences of Slack Resources. 2. Supported by argument a new variable of Soft Slack was developed. Its validity was demonstrated in its ability to capture the contribution of intangible assets, such as education, experience, spare management time and further training, to the extant levels of Organisational Hard Slack resources. 3. The validity of Soft Slack was further supported when its contribution to organisational Flexibility was also established. 4. The original argument that Slack Resources enhance organisational Performance has been further developed. It is now evidenced that Slack Resources facilitate Organisational Flexibility and by this process enhances Organisational Performance.