510 research outputs found
Myth- an extension to C
Myth is a programming language that is an extension of C. Myth adds modules, interfaces, tuple returns, and bit sets. These features are very helpful in nearly any programming environment. The Myth language as a whole is a good choice for embedded systems where resources are limited. Modules help organize code into logical groupings. Interfaces provide an automated mechanism to write reusable code. Tuple returns provide a simple mechanism for returning multiple values from a function. Bitsets make it easy to define logical groups of bit flags. Bisets are particularly useful in code that interfaces with hardware. The advantage of Myth is modules, tuple returns, and interfaces without the overhead of full-blown object orientation. Myth has been implemented as a preprocessor that produces C source code
Needles in the Haystack: Identifying Individuals Present in Pooled Genomic Data
Recent publications have described and applied a novel metric that quantifies the
genetic distance of an individual with respect to two population samples, and
have suggested that the metric makes it possible to infer the presence of an
individual of known genotype in a sample for which only the marginal allele
frequencies are known. However, the assumptions, limitations, and utility of
this metric remained incompletely characterized. Here we present empirical tests
of the method using publicly accessible genotypes, as well as analytical
investigations of the method's strengths and limitations. The results
reveal that the null distribution is sensitive to the underlying assumptions,
making it difficult to accurately calibrate thresholds for classifying an
individual as a member of the population samples. As a result, the
false-positive rates obtained in practice are considerably higher than
previously believed. However, despite the metric's inadequacies for
identifying the presence of an individual in a sample, our results suggest
potential avenues for future research on tuning this method to problems of
ancestry inference or disease prediction. By revealing both the strengths and
limitations of the proposed method, we hope to elucidate situations in which
this distance metric may be used in an appropriate manner. We also discuss the
implications of our findings in forensics applications and in the protection of
GWAS participant privacy
Playing fast and loose with music recognition
We report lessons from iteratively developing a music recognition system to enable a wide range of musicians to embed musical codes into their typical performance practice. The musician composes fragments of music that can be played back with varying levels of embellishment, disguise and looseness to trigger digital interactions. We collaborated with twenty-three musicians, spanning professionals to amateurs and working with a variety of instruments. We chart the rapid evolution of the system to meet their needs as they strove to integrate music recognition technology into their performance practice, introducing multiple features to enable them to trade-off reliability with musical expression. Collectively, these support the idea of deliberately introducing ‘looseness’ into interactive systems by addressing the three key challenges of control, feedback and attunement, and highlight the potential role for written notations in other recognition-based systems
New Generation of Instrumented Ranges: Enabling Automated Performance Analysis
Military training conducted on physical ranges that match a unit’s future operational environment provides
an invaluable experience. Today, to conduct a training exercise while ensuring a unit’s performance is
closely observed, evaluated, and reported on in an After Action Review, the unit requires a number of
instructors to accompany the different elements. Training organized on ranges for urban warfighting brings
an additional level of complexity—the high level of occlusion typical for these environments multiplies the
number of evaluators needed. While the units have great need for such training opportunities, they may not
have the necessary human resources to conduct them successfully. In this paper we report on our US
Navy/ONR-sponsored project aimed at a new generation of instrumented ranges, and the early results we
have achieved. We suggest a radically different concept: instead of recording multiple video streams that
need to be reviewed and evaluated by a number of instructors, our system will focus on capturing dynamic
individual warfighter pose data and performing automated performance evaluation. We will use an in situ
network of automatically-controlled pan-tilt-zoom video cameras and personal position and orientation
sensing devices. Our system will record video, reconstruct dynamic 3D individual poses, analyze,
recognize events, evaluate performances, generate reports, provide real-time free exploration of recorded
data, and even allow the user to generate ‘what-if’ scenarios that were never recorded. The most direct
benefit for an individual unit will be the ability to conduct training with fewer human resources, while
having a more quantitative account of their performance (dispersion across the terrain, ‘weapon flagging’
incidents, number of patrols conducted). The instructors will have immediate feedback on some elements
of the unit’s performance. Having data sets for multiple units will enable historical trend analysis, thus
providing new insights and benefits for the entire service.Office of Naval Researc
Genetic algorithm with logistic regression for prediction of progression to Alzheimer\u27s disease
Assessment of risk and early diagnosis of Alzheimer\u27s disease (AD) is a key to its prevention or slowing the progression of the disease. Previous research on risk factors for AD typically utilizes statistical comparison tests or stepwise selection with regression models. Outcomes of these methods tend to emphasize single risk factors rather than a combination of risk factors. However, a combination of factors, rather than any one alone, is likely to affect disease development. Genetic algorithms (GA) can be useful and efficient for searching a combination of variables for the best achievement (eg. accuracy of diagnosis), especially when the search space is large, complex or poorly understood, as in the case in prediction of AD development. This study showed the potential of GA application in the neural science area. It demonstrated that the combination of a small set of variables is superior in performance than the use of all the single significant variables in the model for prediction of progression of disease. Variables more frequently selected by GA might be more important as part of the algorithm for prediction of disease development
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Principles of metadata organization at the ENCODE data coordination center.
The Encyclopedia of DNA Elements (ENCODE) Data Coordinating Center (DCC) is responsible for organizing, describing and providing access to the diverse data generated by the ENCODE project. The description of these data, known as metadata, includes the biological sample used as input, the protocols and assays performed on these samples, the data files generated from the results and the computational methods used to analyze the data. Here, we outline the principles and philosophy used to define the ENCODE metadata in order to create a metadata standard that can be applied to diverse assays and multiple genomic projects. In addition, we present how the data are validated and used by the ENCODE DCC in creating the ENCODE Portal (https://www.encodeproject.org/). Database URL: www.encodeproject.org
Longitudinal trajectories in cortical thickness and volume atrophy: Superior cognitive performance does not protect against brain atrophy in older adults
Background:
Previous research has identified a small subgroup of older adults that maintain a high level of cognitive functioning well into advanced age. Investigation of those with superior cognitive performance (SCP) for their age is important, as age-related decline has previously been thought to be inevitable.
Objective:
Preservation of cortical thickness and volume was evaluated in 76 older adults with SCP and 100 typical older adults (TOAs) assessed up to five times over six years.
Methods:
Regions of interest (ROIs) found to have been associated with super-aging status (a construct similar to SCP status) in previous literature were investigated, followed by a discovery phase analyses of additional regions. SCPs were aged 70 + at baseline, scoring at/above normative memory (CVLT-II) levels for demographically similar individuals aged 30–44 years old, and in the unimpaired range for all other cognitive domains over the course of the study.
Results:
In linear mixed models, following adjustment for multiple comparisons, there were no significant differences between rates of thinning or volume atrophy between SCPs and TOAs in previously identified ROIs, or the discovery phase analyses. With only amyloid-β negative individuals in the analyses, again there were no significant differences between SCPs and TOAs.
Conclusion:
The increased methodological rigor in classifying groups, together with the influence of cognitive reserve, are discussed as potential factors accounting for our findings as compared to the extant literature on those with superior cognitive performance for their age
The Australian Imaging, Biomarkers and Lifestyle (AIBL) Study of Aging: Methodology and Baseline Characteristics of 1112 Individuals Recruited for a Longitudinal Study of Alzheimer\u27s Disease
Background: The Australian Imaging, Biomarkers and Lifestyle (AIBL) flagship study of aging aimed to recruit 1000 individuals aged over 60 to assist with prospective research into Alzheimer\u27s disease (AD). This paper describes the recruitment of the cohort and gives information about the study methodology, baseline demography, diagnoses, medical comorbidities, medication use, and cognitive function of the participants. Methods: Volunteers underwent a screening interview, had comprehensive cognitive testing, gave 80 ml of blood, and completed health and lifestyle questionnaires. One quarter of the sample also underwent amyloid PET brain imaging with Pittsburgh compound B (PiB PET) and MRI brain imaging, and a subgroup of 10% had ActiGraph activity monitoring and body composition scanning. Results: A total of 1166 volunteers were recruited, 54 of whom were excluded from further study due to comorbid disorders which could affect cognition or because of withdrawal of consent. Participants with AD (211) had neuropsychological profiles which were consistent with AD, and were more impaired than participants with mild cognitive impairment (133) or healthy controls (768), who performed within expected norms for age on neuropsychological testing. PiB PET scans were performed on 287 participants, 100 had DEXA scans and 91 participated in ActiGraph monitoring. Conclusion: The participants comprising the AIBL cohort represent a group of highly motivated and well-characterized individuals who represent a unique resource for the study of AD. They will be reassessed at 18-month intervals in order to determine the predictive utility of various biomarkers, cognitive parameters and lifestyle factors as indicators of AD, and as predictors of future cognitive decline
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