5,418 research outputs found
Functional diversity metrics: how they are affected by landscape change and how they represent ecosystem functioning in the tropics
It is generally expected that landscape changes, such as habitat loss and fragmentation, should negatively affect functional diversity metrics, which in turn impact ecosystem functioning. In this review, we search for studies conducted in the tropics and published in the last 10 years to understand how different aspects of landscape change affect functional diversity metrics and how the latter are associated to ecosystem functioning. In total, we found 24 papers that assessed the effects of landscape metrics on functional diversity, evenness, divergence and composition, and although there was a general trend for functional diversity metrics to improve with habitat cover, we found a wide range of responses. Most surprisingly, however, we only found five studies from the tropics assessing the extent to which functional diversity metrics were correlated to measures of ecosystem functioning, and in general, very weak support was found. In conclusion, our results show that it is crucial to first investigate the level to which functional diversity metrics truly represent or may lead to changes in ecosystem functioning, and this is particularly important for animal communities in the tropics. Without such confirmation, there is little reason to pursue further work to reach a consensus regarding how landscape modification affects functional diversity metrics
A Differential Positioning System Using Modulation Correlation of Signals of Opportunity
Global Navigation Satellite Systems (GNSS) have become the positioning systems of choice for many applications. However, GNSS signals are susceptible to obstruction, interference and jamming. Therefore, to maximize robustness and integrity, it is necessary to employ a dissimilar positioning technology that can operate independently and back-up GNSS. One such technology exploits âsignals of opportunityâ â signals that are designed for purposes other than navigation. This paper presents a system that uses amplitude modulation (AM) radio broadcasts in the medium frequency (MF) band. At these frequencies, the predominant ground-wave propagation mode offers better coverage in remote areas and over sea than is achievable with higher frequency signals. The system is differential and operates by correlating modulation information between the reference and user receivers. A system of this form mitigates the deterioration in and around buildings encountered in prior systems and can provide absolute position using fewer signals than a system using only carrier phase. The system presented in this paper uses generalized cross correlation to obtain time difference of arrival measurements that are subsequently used for position determination. Preliminary results indicate the system provides a robust position solution. Moreover, the system offers the potential to be combined with carrier phase measurements to achieve enhanced performance, while the modulation correlation technique is readily extendable to other types of signal
A New Differential Positioning Method using Modulation Correlation of Signals of Opportunity
Global Navigation Satellite Systems (GNSS) have become the positioning systems of choice for many applications. However, GNSS signals are susceptible to obstruction, interference and jamming. Therefore, to maximize robustness and integrity, it is necessary to employ a dissimilar positioning technology that can operate independently and back-up GNSS. One such technology exploits 'signals of opportunity' - signals that are designed for purposes other than navigation.This paper presents a system that uses amplitude modulation (AM) radio broadcasts in the medium frequency (MF) band. At these frequencies, the predominant ground-wave propagation mode offers better coverage in remote areas and over sea than is achievable with higher frequency signals.The system is differential and operates by correlating modulation information between the reference and user receivers. A system of this form mitigates the deterioration in and around buildings encountered in prior systems and can provide absolute position using fewer signals than a system using only carrier phase.The system presented in this paper uses generalized cross correlation to obtain time difference of arrival measurements that are subsequently used for position determination. Preliminary results indicate the system provides a robust position solution. Moreover, the system offers the potential to be combined with carrier phase measurements to achieve enhanced performance, while the modulation correlation technique is readily extendable to other types of signal
Multi-train trajectory optimisation to maximise rail network energy efficiency under travel-time constraints
Optimising the trajectories of multiple interacting trains to maximise energy efficiency is a difficult, but highly desirable, problem to solve. A bespoke genetic algorithm has been developed for the multi-train trajectory optimisation problem and used to seek a near-optimal set of control point distances for multiple trains, such that a weighted sum of the time and energy objectives is minimised. Genetic operators tailored to the problem are developed including a new mutation operation and the insertion and deletion pairs of control points during the reproduction process. Compared with published results, the new GA was shown to increase the quality of solutions found by an average of 27.6% and increase consistency by a factor of 28. This allows more precise control over the relative priority given to achieving time targets or increasing energy efficiency
Pathology Informatics Essentials for Residents: A Flexible Informatics Curriculum Linked to Accreditation Council for Graduate Medical Education Milestones (a secondary publication)*
Context: Recognition of the importance of informatics to the practice of pathology has surged. Training residents in pathology
informatics has been a daunting task for most residency programs in the United States because faculty often lacks experience and
training resources. Nevertheless, developing resident competence in informatics is essential for the future of pathology as a
specialty.
Objective: To develop and deliver a pathology informatics curriculum and instructional framework that guides pathology
residency programs in training residents in critical pathology informatics knowledge and skills, and meets Accreditation Council
for Graduate Medical Education Informatics Milestones.
Design: The College of American Pathologists, Association of Pathology Chairs, and Association for Pathology Informatics
formed a partnership and expert work group to identify critical pathology informatics training outcomes and to create a highly
adaptable curriculum and instructional approach, supported by a multiyear change management strategy.
Results: Pathology Informatics Essentials for Residents (PIER) is a rigorous approach for educating all pathology residents in
important pathology informatics knowledge and skills. PIER includes an instructional resource guide and toolkit for incorporating informatics training into residency programs that vary in needs, size, settings, and resources. PIER is available at http://
www.apcprods.org/PIER (accessed April 6, 2016).
Conclusions: PIER is an important contribution to informatics training in pathology residency programs. PIER introduces
pathology trainees to broadly useful informatics concepts and tools that are relevant to practice. PIER provides residency program
directors with a means to implement a standardized informatics training curriculum, to adapt the approach to local program
needs, and to evaluate resident performance and progress over time
Interictal epileptiform discharges have an independent association with cognitive impairment in children with lesional epilepsy
OBJECTIVES: The relative contribution of interictal epileptiform discharges (IEDs) to cognitive dysfunction in comparison with the underlying brain pathology is not yet understood in children with lesional focal epilepsy. METHODS: The current study investigated the association of IEDs with intellectual functioning in 103 children with medication-resistant focal epilepsy. Hierarchical multiple regression analyses were used to determine the independent contribution of IED features on intellectual functioning, after controlling for effects of lesional pathology, epilepsy duration, and medication. Exploratory analyses were conducted for language and memory scores as well as academic skills available in a subset of participants. RESULTS: The results reveal that IEDs have a negative association with IQ with independent, additive effects documented for frequent and bilaterally distributed IEDs as well as discharge enhancement in sleep. Left-lateralized IEDs had a prominent effect on verbal intelligence, in excess of the influence of left-sided brain pathology. These effects extended to other cognitive functions, most prominently for sleep-enhanced IEDs to be associated with deficits in expressive and receptive language, reading, spelling and numerical skills. SIGNIFICANCE: Overall, IED effects on cognition were of a magnitude similar to lesional influences or drug effects (topiramate use). This study demonstrates an association between IEDs and cognitive dysfunction, independent of the underlying focal brain pathology
Development of a tool to predict outcome of Autologous Chondrocyte Implantation
Objective. The study had 2 objectives: first, to evaluate the success of autologous chondrocyte implantation (ACI) in
terms of incidence of surgical re-intervention, including arthroplasty, and investigate predictors of successful treatment
outcome. The second objective was to derive a tool predicting a patientâs arthroplasty risk following ACI. Design. In this
Level II, prognostic study, 170 ACI-treated patients (110 males [aged 36.8 ± 9.4 years]; 60 females [aged 38.1 ± 10.2
years]) completed a questionnaire about further surgery on their knee treated with ACI 10.9 ± 3.5 years previously.
Factors commonly assessed preoperatively (age, gender, defect location and number, previous surgery at this site, and the
preoperative Lysholm score) were used as independent factors in regression analyses. Results. At final follow-up (maximum
of 19 years post-ACI), 40 patients (23.5%) had undergone surgical re-intervention following ACI. Twenty-six patients
(15.3%) underwent arthroplasty, more commonly females (25%) than males (10%; P = 0.001). Cox regression analyses
identified 4 factors associated with re-intervention: age at ACI, multiple operations before ACI, patellar defects, and lower
pretreatment Lysholm scores (Nagelkerkeâs R2
= 0.20). Six predictive items associated with risk of arthroplasty following
ACI (Nagelkerkeâs R2
= 0.34) were used to develop the Oswestry Risk of Knee Arthroplasty index with internal crossvalidation. Conclusion. In a single-center study, we have identified 6 factors (age, gender, location and number of defects,
number of previous operations, and Lysholm score before ACI) that appear to influence the likelihood of ACI patients
progressing to arthroplasty. We have used this information to propose a formula or âtoolâ that could aid treatment
decisions and improve patient selection for ACI
The design innovation spectrum: An overview of design influences on innovation for manufacturing companies
This paper discusses the expanding parameters of design and innovation, and constructs a design innovation spectrumâa framework presenting a holistic overview of design influences on innovation, in order to comprehend, assess, and prioritise the areas of improvement to increase the innovativeness of manufacturing companies. The research considers manufacturing industry because re-establishing manufacturing strength is a key agenda for balanced economic growth and stability, especially in advanced countries. This empirical research adopted a triangulation approach that included a literature review to construct a theoretical design innovation spectrum, which was then evaluated through in-depth interviews by eleven design innovation and manufacturing experts to link theories and practicality, and forty-six case studies of manufacturing companies to understand its practical implications. The identified design areas were designing, design strategy, and corporate-level design thinking, which were aligned with the parameters of innovation including technological, product/service, process, and organisational innovation to create a design innovation spectrum, which allows for overall assessment of design innovation capabilities, to be used by both internal and/or external design supporting teams to improve manufacturing companiesâ innovativeness through design
Beyond Design for Manufacture: A Design Innovation Framework
Despite the advantages of using design on a larger scale than simply the product level, many manufacturing companies can't see their way to design as a strategy or a way to improve business management. A framework can help them view the big picture from a design innovation standpoint. Manufacturing firms that hope to achieve innovationâin their products, in their processes, and in their own organizationsâcan use this framework to identify opportunities, prioritize problem-solving, and work toward systematic improvement
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