Behavioral simulation and synthesis of biological neuron systems using synthesizable VHDL

Neurons are complex biological entities which form the basis of nervous systems. Insight can be gained into neuron behavior through the use of computer models and as a result many such models have been developed. However, there exists a trade-off between biological accuracy and simulation time with the most realistic results requiring extensive computation. To address this issue, a novel approach is described in this paper that allows complex models of real biological systems to be simulated at a speed greater than real time and with excellent accuracy. The approach is based on a specially developed neuron model VHDL library which allows complex neuron systems to be implemented on field programmable gate array (FPGA) hardware. The locomotion system of the nematode Caenorhabditis elegans is used as a case study and the measured results show that the real time FPGA based implementation performs 288 times faster than traditional ModelSim simulations for the same accuracy

Yield improvement using configurable analogue transistors (CATs)

Continued process scaling has led to significant yield and reliability challenges for today’s designers. Analogue circuits are particularly susceptible to poor variation, driving the need for new yield resilient techniques in this area. This paper describes a new configurable analogue transistor structure and supporting methodology that facilitates variation compensation at the post-manufacture stage. The approach has demonstrated significant yield improvements and can be applied to any analogue circui

Bed-load Transport of Mixed-size Sediment: Fractional Transport Rates, Bed Forms, and the Development of a Coarse Bed-surface Layer

Fractional transport rates, bed surface texture, and bed configuration were measured after a mixed size sediment had reached an equilibrium transport state for seven different flow strengths in a recirculating laboratory flume. Fractional transport rates were also measured at the beginning of each run when the bed was well mixed and planar. The start-up observations allow us to describe the variation of fractional transport rates with bed shear stress for a constant bed surface texture and bed configuration. The start-up and equilibrium observations together allow, for the first time, an unambiguous description of the mutual adjustment among the transport, the bed configuration, and the bed surface, as the transport system moves toward equilibrium. We find that a substantial interaction exists among the transport, bed surface, and bed configuration. Bed forms and a coarse surface layer coexist over a range of bed shear stress. Under some flow conditions the size and shape of the bed forms are controlled by the presence of the coarse surface layer. At higher flows the coarse surface layer is eliminated by scour in the lee of the bed forms. If the bed surface is defined as that over which the bed forms move, a coherent relation between the bed surface texture and the transport grain size distribution may be defined. At equilibrium the transport rates of all fractions were not equally mobile, defined as identical transport and bed grain size distributions, although equal mobility was approached for runs in which the bed shear stress was more than twice that for initial motion of the mixture. Under some flow conditions the transport was observed to adjust away from equal mobility as the bed adjusted from a well-mixed start-up condition to an equilibrium state. Development of a partial static armor, wherein some individual grains become essentially immobile even though other grains in the same fraction remain in transport, is suggested to explain these adjustments between the transport and bed surface grain size distributions. Constraints on equilibrium mixed size sediment transport are defined. The special conditions for which equal mobility must hold and the relevance to natural conditions of flume results and the equal mobility concept are discussed

The performance of eyewitnesses with intellectual disabilities on identification lineups

Despite the large number of people with intellectual disabilities (ID) and the fact they are more likely to be victims and witnesses of crime, only two published studies have investigated their performance on identification line-up parades. In the present study we examined the identification performance of adults with and without ID on both a perpetrator-present and a perpetrator-absent photographic line-up. In addition, we investigated factors that could explain any potential difficulties with identification performance, such as face recognition performance (as measured by a standardised test), eyewitness confidence, understanding of the purpose of a line-up, and memory for non-biased line-up instructions. In comparison with typical adults, participants with ID demonstrated poorer performance across both perpetrator-present and perpetrator-absent photographic line-ups, yet were more confident in the accuracy of their responses. In addition they had poorer face recognition performance, were less likely to understand the purpose of the line-up, and were less likely to remember the non-biased line-up instructions. This pattern of difficulties is discussed in relation to the development of future research and interventions

The narrative coherence of witness transcripts in children on the autism spectrum

Background and Aims. Autistic children often recall fewer details about witnessed events than typically developing children (of comparable age and ability), although the information they recall is generally no less accurate. Previous research has not examined the narrative coherence of such accounts, despite higher quality narratives potentially being perceived more favourably by criminal justice professionals and juries. This study compared the narrative coherence of witness transcripts produced by autistic and typically developing (TD) children (ages 6-11 years, IQs 70+). Methods and Procedures. Secondary analysis was carried out on interview transcripts from a subset of 104 participants (autism=52, TD=52) who had taken part in a larger study of eyewitness skills in autistic and TD children. Groups were matched on chronological age, IQ and receptive language ability. Coding frameworks were adopted from existing narrative research, featuring elements of ‘story grammar’. Outcomes and Results. Whilst fewer event details were reported by autistic children, there were no group differences in narrative coherence (number and diversity of ‘story grammar’ elements used), narrative length or semantic diversity. Conclusions and Implications. These findings suggest that the narrative coherence of autistic children’s witness accounts is equivalent to TD peers of comparable age and ability

Closing the Gap Between Watershed Modeling, Sediment Budgeting, and Stream Restoration

The connection between stream restoration and sediment budgeting runs both ways: stream restoration is proposed as a means to reduce sediment yields, but an accurate understanding of sediment supply is necessary to design an effective project. Recent advances in monitoring technology, geochemical techniques, high-resolution topography data, and numerical modeling provide new opportunities to estimate sediment erosion, transport, and deposition rates; upscale them in a geomorphically relevant fashion; and synthesize sediment dynamics at watershed scales. For practical application at large scale, watershed models used to predict yield often do not resolve lower-order channels, leaving an essential “blind spot” regarding sediment processes. We illustrate the challenges and emerging approaches for estimating sediment budgets using examples from two very different physiographic settings: the Mid-Atlantic Piedmont and the agricultural plains of southern Minnesota. We highlight common challenges and themes in defining an effective watershed sediment model. In both cases, reliable estimates of sediment yield depend essentially on the accurate identification of sediment sources and sinks and, hence, require careful delineation of landscape units and identification of dominant sediment sources and sinks. The primary elements needed to bridge the gap between sediment budgeting, watershed modeling, and stream restoration are (1) specificity regarding location, mechanism, and rates of erosion, (2) accurate accounting of sediment storage, (3) appropriate methods for upscaling local observations, (4) efficient means for incorporating multiple lines of evidence to constrain budget estimates, and (5) stream restoration methods that incorporate sediment supply in assessment and design procedures

General practitioners' and psychiatrists' attitudes towards antidepressant withdrawal.

BACKGROUND: There has been a recent rise in antidepressant prescriptions. After the episode for which it was prescribed, the patient should ideally be supported in withdrawing the medication. There is increasing evidence for withdrawal symptoms (sometimes called discontinuation symptoms) occurring on ceasing treatment, sometimes having severe or prolonged effects. AIMS: To identify and compare current knowledge, attitudes and practices of general practitioners (GPs) and psychiatrists in Cornwall, UK, concerning antidepressant withdrawal symptoms. METHOD: Questions about withdrawal symptoms and management were asked of GPs and psychiatrists in a multiple-choice cross-sectional study co-designed with a lived experience expert. RESULTS: Psychiatrists thought that withdrawal symptoms were more severe than GPs did (P = 0.003); 53% (22/42) of GPs and 69% (18/26) of psychiatrists thought that withdrawal symptoms typically last between 1 and 4 weeks, although there was a wide range of answers given; 35% (9/26) of psychiatrists but no GPs identified a pharmacist as someone they may use to help manage antidepressant withdrawal. About three-quarters of respondents claimed they usually or always informed patients of potential withdrawal symptoms when they started a patient on antidepressants, but patient surveys say only 1% are warned. CONCLUSIONS: Psychiatrists and GPs need to effectively warn patients of potential withdrawal effects. Community pharmacists might be useful in supporting GP-managed antidepressant withdrawal. The wide variation in responses to most questions posed to participants reflects the variation in results of research on the topic. This highlights a need for more reproducible studies to be carried out on antidepressant withdrawal, which could inform future guidelines

Hyperhomocysteinemia as a Risk Factor for Vascular Contributions to Cognitive Impairment and Dementia

Behind only Alzheimer’s disease, vascular contributions to cognitive impairment and dementia (VCID) is the second most common cause of dementia, affecting roughly 10–40% of dementia patients. While there is no cure for VCID, several risk factors for VCID, such as diabetes, hypertension, and stroke, have been identified. Elevated plasma levels of homocysteine, termed hyperhomocysteinemia (HHcy), are a major, yet underrecognized, risk factor for VCID. B vitamin deficiency, which is the most common cause of HHcy, is common in the elderly. With B vitamin supplementation being a relatively safe and inexpensive therapeutic, the treatment of HHcy-induced VCID would seem straightforward; however, preclinical and clinical data shows it is not. Clinical trials using B vitamin supplementation have shown conflicting results about the benefits of lowering homocysteine and issues have arisen over proper study design within the trials. Studies using cell culture and animal models have proposed several mechanisms for homocysteine-induced cognitive decline, providing other targets for therapeutics. For this review, we will focus on HHcy as a risk factor for VCID, specifically, the different mechanisms proposed for homocysteine-induced cognitive decline and the clinical trials aimed at lowering plasma homocysteine

Climate change mitigation for agriculture: water quality benefits and costs

New Zealand is unique in that half of its national greenhouse gas (GHG) inventory derives from agriculture--predominantly as methane (CH4) and nitrous oxide (N2O), in a 2:1 ratio. The remaining GHG emissions predominantly comprise carbon dioxide (CO2) deriving  from  energy  and  industry  sources.  Proposed strategies to  mitigate  emissions  of  CH4  and  N2O  from  pastoral  agriculture in New Zealand are: (1) utilising extensive and riparian afforestation of pasture to achieve CO2 uptake (carbon sequestration); (2) management of nitrogen through budgeting and/or the use of nitrification inhibitors, and minimising soil anoxia to reduce N2O emissions; and (3) utilisation of alternative waste treatment technologies to minimise emissions of CH4. These mitigation measures have associated co-benefits and co-costs (disadvantages) for rivers, streams and lakes because they affect land use, runoff loads, and receiving water and habitat quality. Extensive afforestation results in lower specific yields (exports) of nitrogen (N), phosphorus (P), suspended sediment (SS) and faecal matter and also has benefits for stream habitat quality by improving stream temperature, dissolved oxygen and pH regimes through greater shading, and the supply of woody debris and terrestrial food resources. Riparian afforestation does not achieve the same reductions in exports as extensive afforestation but can achieve reductions in concentrations of N, P, SS and faecal organisms. Extensive afforestation of pasture leads to reduced water yields and stream flows. Both afforestation measures produce intermittent disturbances to waterways during forestry operations (logging and thinning), resulting in sediment release from channel re-stabilisation and localised flooding, including formation of debris dams at culverts. Soil and fertiliser management benefits aquatic ecosystems by reducing N exports but the use of nitrification inhibitors, viz. dicyandiamide (DCD), to achieve this may under some circumstances impair wetland function to intercept and remove nitrate from drainage water, or even add to the overall N loading to waterways. DCD is water soluble and degrades rapidly in warm soil conditions. The recommended application rate of 10 kg DCD/ha corresponds to 6 kg N/ha and may be exceeded in warm climates. Of the N2O produced by agricultural systems, approximately 30% is emitted from indirect sources, which are waterways draining agriculture. It is important therefore to focus strategies for managing N inputs to agricultural systems generally to reduce inputs to wetlands and streams where these might be reduced to N2O. Waste management options include utilising the CH4 resource produced in farm waste treatment ponds as a source of energy, with conversion to CO2 via combustion achieving a 21-fold reduction in GHG emissions. Both of these have co-benefits for waterways as a result of reduced loadings. A conceptual model derived showing the linkages between key land management practices for greenhouse gas mitigation and key waterway values and ecosystem attributes is derived to aid resource managers making decisions affecting waterways and atmospheric GHG emissions

Rapport‐building in multiple interviews of children

AbstractRapport‐building is key in child investigative interviews, however, recommendations of how to build rapport differ. Additionally, rapport in more complex situations: when a child is interviewed repeatedly or requires separate rapport building have not been studied. This research examined the UK's ‘Achieving Best Evidence’ guidelines for rapport‐building, which recommend conducting a neutral discussion, compared with a control condition and a separate rapport‐building session for first interviews on children's recall and well‐being (measured by state anxiety and rapport questionnaires). For second and third interviews, additional full rapport‐building sessions were compared to shortened or no rapport‐building conditions. No significant differences in children's (N = 107) recall or well‐being were found across rapport‐building conditions for all interviews. We conclude that for children who have experienced non‐traumatic events, the inclusion of a neutral discussion rapport‐building phase may not be any more beneficial for children than conducting a friendly interview