Synthesis of application specific processor architectures for ultra-low energy consumption

In this paper we suggest that further energy savings can be achieved by a new approach to synthesis of embedded processor cores, where the architecture is tailored to the algorithms that the core executes. In the context of embedded processor synthesis, both single-core and many-core, the types of algorithms and demands on the execution efficiency are usually known at the chip design time. This knowledge can be utilised at the design stage to synthesise architectures optimised for energy consumption. Firstly, we present an overview of both traditional energy saving techniques and new developments in architectural approaches to energy-efficient processing. Secondly, we propose a picoMIPS architecture that serves as an architectural template for energy-efficient synthesis. As a case study, we show how the picoMIPS architecture can be tailored to an energy efficient execution of the DCT algorithm

Strategies to augment volitional and reflex function may improve locomotor capacity following incomplete spinal cord injury

Many studies highlight the remarkable plasticity demonstrated by spinal circuits following an incomplete spinal cord injury (SCI). Such plasticity can contribute to improvements in volitional motor recovery, such as walking function, although similar mechanisms underlying this recovery may also contribute to the manifestation of exaggerated responses to afferent input, or spastic behaviors. Rehabilitation interventions directed toward augmenting spinal excitability have shown some initial success in improving locomotor function. However, the potential effects of these strategies on involuntary motor behaviors may be of concern. In this article, we provide a brief review of the mechanisms underlying recovery of volitional function and exaggerated reflexes, and the potential overlap between these changes. We then highlight findings from studies that explore changes in spinal excitability during volitional movement in controlled conditions, as well as altered kinematic and behavioral performance during functional tasks. The initial focus will be directed toward recovery of reflex and volitional behaviors following incomplete SCI, followed by recent work elucidating neurophysiological mechanisms underlying patterns of static and dynamic muscle activation following chronic incomplete SCI during primarily single-joint movements. We will then transition to studies of locomotor function and the role of altered spinal integration following incomplete SCI, including enhanced excitability of specific spinal circuits with physical and pharmacological interventions that can modulate locomotor output. The effects of previous and newly developed strategies will need to focus on changes in both volitional function and involuntary spastic reflexes for the successful translation of effective therapies to the clinical setting

Mucosal neuroimmune mechanisms in gastro-oesophageal reflux disease (GORD) pathogenesis.

Gastro-oesophageal reflux disease (GORD) is a chronic condition characterised by visceral pain in the distal oesophagus. The current first-line treatment for GORD is proton pump inhibitors (PPIs), however, PPIs are ineffective in a large cohort of patients and long-term use may have adverse effects. Emerging evidence suggests that nerve fibre number and location are likely to play interrelated roles in nociception in the oesophagus of GORD patients. Simultaneously, alterations in cells of the oesophageal mucosa, namely epithelial cells, mast cells, dendritic cells, and T lymphocytes, have been a focus of GORD research for several years. The oesophagus of GORD patients exhibits both macro- and micro-inflammation as a response to chronic acidic reflux at the epithelium. In other conditions of the GI tract, such as IBS and IBD, well-characterised bidirectional processes between immune cells and mucosal nerve fibres contribute to pathogenesis and symptom generation. Sensory alterations in these conditions such as nerve fibre outgrowth and hypersensitivity can be driven by inflammatory processes, which promote visceral pain signalling. This review will examine what is currently known of the molecular pathways linking inflammation and sensory perception leading to the development of GORD symptoms and explore potentially relevant mechanisms in other GI regions which may indicate new areas in GORD research

Voltage imaging of waking mouse cortex reveals emergence of critical neuronal dynamics.

Complex cognitive processes require neuronal activity to be coordinated across multiple scales, ranging from local microcircuits to cortex-wide networks. However, multiscale cortical dynamics are not well understood because few experimental approaches have provided sufficient support for hypotheses involving multiscale interactions. To address these limitations, we used, in experiments involving mice, genetically encoded voltage indicator imaging, which measures cortex-wide electrical activity at high spatiotemporal resolution. Here we show that, as mice recovered from anesthesia, scale-invariant spatiotemporal patterns of neuronal activity gradually emerge. We show for the first time that this scale-invariant activity spans four orders of magnitude in awake mice. In contrast, we found that the cortical dynamics of anesthetized mice were not scale invariant. Our results bridge empirical evidence from disparate scales and support theoretical predictions that the awake cortex operates in a dynamical regime known as criticality. The criticality hypothesis predicts that small-scale cortical dynamics are governed by the same principles as those governing larger-scale dynamics. Importantly, these scale-invariant principles also optimize certain aspects of information processing. Our results suggest that during the emergence from anesthesia, criticality arises as information processing demands increase. We expect that, as measurement tools advance toward larger scales and greater resolution, the multiscale framework offered by criticality will continue to provide quantitative predictions and insight on how neurons, microcircuits, and large-scale networks are dynamically coordinated in the brain

An assessment of the strength of knots and splices used as eye terminations in a sailing environment

Research into knots, splices and other methods of forming an eye termination has been limited, despite the fact that they are essential and strongly affect the performance of a rope. The aim of this study was to carry out a comprehensive initial assessment of the breaking strength of eye terminations commonly used in a sailing environment, thereby providing direction for further work in the field. Supports for use in a regular tensile testing machine were specially developed to allow individual testing of each sample and a realistic spread of statistical data to be obtained. Over 180 break tests were carried out on four knots (the bowline, double bowline, figure-of-eight loop and perfection loop) and two splices (three-strand eye splice and braid-on-braid splice). The factors affecting their strength were investigated. A statistical approach to the analysis of the results was adopted. The type of knot was found to have a significant effect on the strength. This same effect was seen in both types of rope construction (three-strand and braid-on-braid). Conclusions were also drawn as to the effect of splice length, eye size, manufacturer and rope diameter on the breaking strength of splices. Areas of development and further investigation were identified

Homology of Distributive Lattices

We outline the theory of sets with distributive operations: multishelves and multispindles, with examples provided by semi-lattices, lattices and skew lattices. For every such a structure we define multi-term distributive homology and show some of its properties. The main result is a complete formula for the homology of a finite distributive lattice. We also indicate the answer for unital spindles and conjecture the general formula for semi-lattices and some skew lattices. Then we propose a generalization of a lattice as a set with a number of idempotent operations satisfying the absorption law.Comment: 30 pages, 3 tables, 3 figure

Qualitative Analysis Techniques for the Review of the Literature

In this article, we provide a framework for analyzing and interpreting sources that inform a literature review or, as it is more aptly called, a research synthesis. Specifically, using Leech and Onwuegbuzie’s (2007, 2008) frameworks, we delineate how the following four major source types inform research syntheses: talk, observations, drawings/photographs/videos, and documents. We identify 17 qualitative data analysis techniques that are optimal for analyzing one or more of these source types. Further, we outline the role that the following five qualitative data analysis techniques can play in the research synthesis: constant comparison analysis, domain analysis, taxonomic analysis, componential analysis, and theme analysis. We contend that our framework represents a first step in an attempt to help literature reviewers analyze and interpret literature in an optimally rigorous way

Interactive effects of social environment, age and sex on immune responses in Drosophila melanogaster

Social environments have been shown to have multiple effects on individual immune responses. For example, increased social contact might signal greater infection risk and prompt a prophylactic upregulation of immunity. This differential investment of resources may in part explain why social environments affect ageing and lifespan. Our previous work using Drosophila melanogaster showed that single-sex social contact reduced lifespan for both sexes. Here, we assess how social interactions (isolation or contact) affect susceptibility to infection, phagocytotic activity and expression of a subset of immune and stress related genes in young and old flies of both sexes. Social contact had a neutral, or even improved, effect on post-infection lifespan in older flies and reduced the expression of stress response genes in females, however it reduced phagocytotic activity. Overall the effects of social environment were complex and largely subtle, and do not indicate a consistent effect. Together, these findings indicate that social contact in D. melanogaster does not have a predictable impact on immune responses and does not simply trade-off immune investment with lifespan

Selective antagonism of cJun for cancer therapy

The activator protein-1 (AP-1) family of transcription factors modulate a diverse range of cellular signalling pathways into outputs which can be oncogenic or anti-oncogenic. The transcription of relevant genes is controlled by the cellular context, and in particular by the dimeric composition of AP-1. Here, we describe the evidence linking cJun in particular to a range of cancers. This includes correlative studies of protein levels in patient tumour samples and mechanistic understanding of the role of cJun in cancer cell models. This develops an understanding of cJun as a focal point of cancer-altered signalling which has the potential for therapeutic antagonism. Significant work has produced a range of small molecules and peptides which have been summarised here and categorised according to the binding surface they target within the cJun-DNA complex. We highlight the importance of selectively targeting a single AP-1 family member to antagonise known oncogenic function and avoid antagonism of anti-oncogenic function

Domain-general subregions of the medial prefrontal cortex contribute to recovery of language after stroke

We hypothesized that the recovery of speech production after left hemisphere stroke not only depends on the integrity of language-specialized brain systems, but also on ‘domain-general’ brain systems that have much broader functional roles. The presupplementary motor area/dorsal anterior cingulate forms part of the cingular-opercular network, which has a broad role in cognition and learning. Consequently, we have previously suggested that variability in the recovery of speech production after aphasic stroke may relate in part to differences in patients’ abilities to engage this domain-general brain region. To test our hypothesis, 27 patients (aged 59 ± 11 years) with a left hemisphere stroke performed behavioural assessments and event-related functional magnetic resonance imaging tasks at two time points; first in the early phase (∼2 weeks) and then ∼4 months after the ictus. The functional magnetic resonance imaging tasks were designed to differentiate between activation related to language production (sentential overt speech production—Speech task) and activation related to cognitive processing (non-verbal decision making). Simple rest and counting conditions were also included in the design. Task-evoked regional brain activations during the early and late phases were compared with a longitudinal measure of recovery of language production. In accordance with a role in cognitive processing, substantial activity was observed within the presupplementary motor area/dorsal anterior cingulate during the decision-making task. Critically, the level of activation within this region during speech production correlated positively with the longitudinal recovery of speech production across the two time points (as measured by the in-scanner performance in the Speech task). This relationship was observed for activation in both the early phase (r = 0.363, P = 0.03 one-tailed) and the late phase (r = 0.538, P = 0.004). Furthermore, presupplementary motor area/dorsal anterior cingulate activity was a predictor of both language recovery over time and language outcome at ∼4 months, over and above that predicted by lesion volume, age and the initial language impairment (general linear model overall significant at P < 0.0001; ExpB 1.01, P = 0.02). The particularly prominent relationship of the presupplementary motor area/dorsal anterior cingulate region with recovery of language was confirmed in voxel-wise correlation analysis, conducted unconstrained for the whole brain volume. These results accord with the hypothesis that the functionality of the presupplementary motor area/dorsal anterior cingulate contributes to language recovery after stroke. Given that this brain region is often spared in aphasic stroke, we propose that it is a sensible target for future research into rehabilitative treatments. More broadly, baseline assessment of domain-general systems could help provide a better prediction of language recovery