Comparison of spatial domain optimal trade-off maximum average correlation height (OT-MACH) filter with scale invariant feature transform (SIFT) using images with poor contrast and large illumination gradient

A spatial domain optimal trade-off Maximum Average Correlation Height (OT-MACH) filter has been previously developed and shown to have advantages over frequency domain implementations in that it can be made locally adaptive to spatial variations in the input image background clutter and normalised for local intensity changes. In this paper we compare the performance of the spatial domain (SPOT-MACH) filter to the widely applied data driven technique known as the Scale Invariant Feature Transform (SIFT). The SPOT-MACH filter is shown to provide more robust recognition performance than the SIFT technique for demanding images such as scenes in which there are large illumination gradients. The SIFT method depends on reliable local edge-based feature detection over large regions of the image plane which is compromised in some of the demanding images we examined for this work. The disadvantage of the SPOTMACH filter is its numerically intensive nature since it is template based and is implemented in the spatial domain. © (2015) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only

Electrical properties of breast cancer cells from impedance measurement of cell suspensions

Impedance spectroscopy of biological cells has been used to monitor cell status, e.g. cell proliferation, viability, etc. It is also a fundamental method for the study of the electrical properties of cells which has been utilised for cell identification in investigations of cell behaviour in the presence of an applied electric field, e.g. electroporation. There are two standard methods for impedance measurement on cells. The use of microelectrodes for single cell impedance measurement is one method to realise the measurement, but the variations between individual cells introduce significant measurement errors. Another method to measure electrical properties is by the measurement of cell suspensions, i.e. a group of cells within a culture medium or buffer. This paper presents an investigation of the impedance of normal and cancerous breast cells in suspension using the Maxwell-Wagner mixture theory to analyse the results and extract the electrical parameters of a single cell. The results show that normal and different stages of cancer breast cells can be distinguished by the conductivity presented by each cell. © 2010 IOP Publishing Ltd

A 3D multi-frequency response electrical mesh phantom for validation of the planar structure EIT system performance

Assessment and validation of the Electrical Impedance Tomography (EIT) system performance and calibration of systematic errors in the electrical field generated inside of the interrogated volume is an important requirement. System instabilities can be caused by the EIT design and must be characterized before and during the clinical trials. Evaluation of the Sussex EIT system used in the clinical study can be based on a realistic electronic phantom. We designed a mesh phantom based on the electrode configuration and mesh structures of the image reconstruction. The phantom has the capability of modelling the cellular electrical properties that are operative within a circular homogeneous medium. The design is optimized to assess the planar topology of the internal impedance distribution. The system employs the information from the electrical properties of biological tissues to evaluate the Cole-Cole dispersion data. This mesh phantom is capable of producing localized conductivity perturbations between each arbitrary channel in the electrode placement planar phantom topology by measuring all 1416 combinations that are to be used in the image reconstruction. The phantom is especially designed for the Sussex EIT system to validate system performance of measurements consisting of SNR, and modelling system accuracy

Comparison of Howland and General Impedance Converter (GIC) circuit based current sources for bio-impedance measurements

The current source is a key component in bio-impedance measurement systems. The accuracy of the current source can be measured in terms of its output impedance together with other parameters, with certain applications demanding extremely high output impedance. This paper presents an investigation and comparison of different current source designs based on the Enhanced Howland circuit combined with a General Impedance Converter (GIC) circuit using both ideal and non-ideal operational amplifiers. Under differing load conditions two different settings of the GIC are evaluated and the results are compared to show its performance settings. Whilst the study has shown that over a wide bandwidth (i.e. 100Hz-100MHz) the output impedance is limited, operation over a more limited range offers output impedance in the Giga-ohm range, which can be considered as being infinite

Changes in Cormorant Populations in the Strait of Georgia, British Columbia, 1955-2015

Between 1987 and 2000, nesting populations of Pelagic Cormorant (Phalacrocorax pelagicus; PECO) and Double-crested Cormorant (P. auritus; DCCO) declined in the Strait of Georgia, BC. This northern section of the Salish Sea is a rapidly urbanizing area, and piscivorous birds are important indicators of ecosystem health. To update population status, we conducted a complete survey of 35 PECO and 23 DCCO colonies in July 2014 and opportunistic surveys of some colonies between 2001 through 2015. The PECO population decreased from ~2100-2400 nests in 1959-1987 to ~1100 nests by about 2000, and then rose slightly to ~1600 nests by 2015. The DCCO population increased from ~200 nests in 1959 to ~2,000 nests in 1987, before decreasing to ~600 nests in 2000, and then remained at this level through 2015. Many smaller colonies no longer exist and the majority of PECO and DCCO currently nest in three locations: Mandarte Island, Mitlenatch Island, and bridges in Vancouver. The main factors affecting population changes from about 1990 to 2015 include reduced prey availability, increased Bald Eagle (Haliaeetus leucocephalus) predation, and use of man-made structures for nesting at certain colonies. In 2013-2015, small numbers of Brandt’s Cormorants (P. penicillatus) nested at Mandarte Island. This is the first reported nesting of Brandt’s Cormorants nesting in the Strait of Georgia

A four-step ortho-rectification procedure for geo-referencing video streams from a low-cost UAV

In this paper, we present a four-step ortho-rectification procedure for real-time geo-referencing of video data from a low-cost UAV equipped with a multi-sensor system. The basic procedures for the real-time ortho-rectification are: (1) decompilation of the video stream into individual frames; (2) establishing the interior camera orientation parameters; (3) determining the relative orientation parameters for each video frame with respect to each other; (4) finding the absolute orientation parameters, using a self-calibration bundle and adjustment with the aid of a mathematical model. Each ortho-rectified video frame is then mosaicked together to produce a mosaic image of the test area, which is then merged with a well referenced existing digital map for the purpose of geo-referencing and aerial surveillance. A test field located in Abuja, Nigeria was used to evaluate our method. Video and telemetry data were collected for about fifteen minutes, and they were processed using the four-step ortho-rectification procedure. The results demonstrated that the geometric measurement of the control field from ortho-images is more accurate when compared with those from original perspective images when used to pin point the exact location of targets on the video imagery acquired by the UAV. The 2-D planimetric accuracy when compared with the 6 control points measured by a GPS receiver is between 3 to 5 metres

Automation Hooks Architecture Trade Study for Flexible Test Orchestration

We describe the conclusions of a technology and communities survey supported by concurrent and follow-on proof-of-concept prototyping to evaluate feasibility of defining a durable, versatile, reliable, visible software interface to support strategic modularization of test software development. The objective is that test sets and support software with diverse origins, ages, and abilities can be reliably integrated into test configurations that assemble and tear down and reassemble with scalable complexity in order to conduct both parametric tests and monitored trial runs. The resulting approach is based on integration of three recognized technologies that are currently gaining acceptance within the test industry and when combined provide a simple, open and scalable test orchestration architecture that addresses the objectives of the Automation Hooks task. The technologies are automated discovery using multicast DNS Zero Configuration Networking (zeroconf), commanding and data retrieval using resource-oriented Restful Web Services, and XML data transfer formats based on Automatic Test Markup Language (ATML). This open-source standards-based approach provides direct integration with existing commercial off-the-shelf (COTS) analysis software tools

Not particularly special: critiquing ‘NPS’ as a category of drugs

Novel Psychoactive Substances (NPS) have been a dominant feature of drug discourse for many years now and, in academic, policy and public discourse, have become established as a new – and by implication, distinct – category of drugs. We argue that this understanding of NPS is fundamentally problematic. Differences within the category are obscured, as are similarities between NPS and more established categories of drugs. Focusing on NPS as something new, different or particularly special is misleading and counterproductive and can have serious consequences in terms of understanding the bigger picture in relation to illegal drugs more generally. This has led to overestimations of the size of the NPS problem, obfuscation of the common underlying causes of dependent drug use, and the implementation of significant and problematic policy changes. Further, a failure to see the rise in NPS as just one of a number of emerging trends in contemporary drug scenes, alongside the development of online markets or the rise in domestic drug production operations, for example, impairs our ability to understand the wider societal, cultural and theoretical underpinnings of drug use. NPS are not particularly special: treating them as such can have dangerous and far-reaching consequences

A randomised controlled trial to compare the cost-effectiveness of tricyclic antidepressants, selective serotonin reuptake inhibitors and lofepramine

Aim/ Principal Research Question - The main aim of the “AHEAD” study was to determine the relative cost-effectiveness of three classes of antidepressants: tricyclics (TCAs), selective serotonin reuptake inhibitors (SSRIs), and the tricyclic-related antidepressant lofepramine, as first choice treatments for depression in UK primary care. Factors of interest - This is the first randomised prospective study in UK primary care to address this question. Most previous work on this topic has relied upon modelling and/or post hoc analysis of data collected for other purposes. The only other published trial of this type was conducted in HMOs in the United States.Methods - The study was an open label, pragmatic controlled trial with three randomised arms and one preference arm. Patients were followed up for a total of 12 months. Patients were randomised to receive a tricyclic antidepressant (amitriptyline, dothiepin, or imipramine), a selective serotonin reuptake inhibitor (fluoxetine, sertraline, or paroxetine), or lofepramine. Standardised recommendations about dose and dose escalation based on the BNF were issued to GPs. Cost effectiveness was based upon an analysis of direct costs from an NHS perspective.Sample groups - The study was carried out in UK primary care: 73 practices in urban and rural areas in Hampshire, Wiltshire, Dorset, Sussex, and Surrey agreed initially to take part. Patients with a new episode of depressive illness according to GP diagnosis were recruited. A total of 388 patients were referred to the study team by 87 GPs from 55 practices. Incremental cost-effectiveness ratios and cost-effectiveness acceptability curves (CEACs) were computed. Estimates were bootstrapped with 5000 replications.Outcome measures - At baseline the Clinical Interview Schedule, Revised (CIS-R PROQSY computerised version) was administered to establish symptom profiles. Outcome measures over 12 month follow-up included the Hospital Anxiety and Depression Scale self-rating of depression (HAD-D), CIS-R, EuroQol (EQ-5D) for quality of life, Short Form (SF-36) Health Survey for generic health status, and patient and practice records of use of health and social services (UHSS). The primary effectiveness outcome was the number of depression-free weeks (HAD-D less than 8, with interpolation of intervening values), and the primary cost outcome total direct NHS costs. Quality adjusted life years (QALYs) were used as the outcome measure in a secondary analysis. Findings - 327 patients were randomised. Follow-up rates were 68% at 3 months and 52% at 1 year. Linear regression analysis revealed no significant differences between groups in number of depression-free weeks when adjusted for baseline HAD-D. A higher proportion of patients randomised to TCAs entered the preference arm than those allocated to the other choices. Switching to another class of antidepressant in the first few weeks of treatment occurred significantly more often in the lofepramine arm and less in the preference arm. There were no significant differences between arms in mean cost per depression-free week. For values placed on an additional QALY of over £5,000, treatment with SSRIs was likely to be the most cost-effective strategy. Tricyclics were the least likely to be cost-effective as first choice of antidepressant for most values of a depression free week or QALY respectively, but these differences were relatively modest.Conclusion - Given the low probability of significant differences in cost-effectiveness, it is appropriate to base the first choice between these three classes of antidepressant in primary care on doctor and patient preferences. Adopting this policy may lead to less switching of medication subsequently. Choosing lofepramine is likely to lead to a greater proportion of patients switching treatment in the first few weeks.Implications for further research - It is difficult to see how a better study of this topic could be conducted in the primary care setting. The research agenda concerning the management of depression in primary care should move on to address important questions such as the most appropriate threshold of severity at which to commence antidepressant medication, the effectiveness of strategies to improve recognition of depression and quality of management of identified patients, and the efficacy of interventions to improve persistence in treatment taking by patients

Organisational barriers to the facilitation of overseas volunteering and training placements in the NHS

Background Undertaking a period of voluntary work or a professional placement overseas has long been a feature of medical training in the UK. There are now a number of high profile National Health Service (NHS) initiatives aimed at increasing access to such opportunities for staff at all levels. We present findings from a qualitative study involving a range of NHS staff and other stakeholders which explored barriers to participation in these activities. Methods A grounded theory methodology was drawn upon to conduct thematic based analysis. Our data included in-depth, semi-structured interviews with a range of returned volunteers, non-volunteers and other stakeholders (n=51) who were, or had been, employed by the NHS. Results There are significant barriers to placement and volunteering activity stemming from structural and organisational shortcomings within the NHS. Difficulties in filling clinical roles has a significant impact on the ability of staff to plan and undertake independent placements. There is currently no clearly defined pathway within the NHS by which the majority of grades can apply for, or organise, a period of overseas voluntary or professional placement activity. There were divergent views on the relevance and usefulness of overseas professional placements. Conclusions We argue that in the context of current UK policy initiatives aimed at facilitating overseas volunteer and professional placement activity, urgent attention needs to be given to the structural and organisational framework within which such initiatives will be required to work