1,263 research outputs found
A Description Logic of Typicality for Conceptual Combination
We propose a nonmonotonic Description Logic of typicality able to
account for the phenomenon of combining prototypical concepts, an open problem
in the fields of AI and cognitive modelling. Our logic extends the logic of
typicality ALC + TR, based on the notion of rational closure, by inclusions
p :: T(C) v D (“we have probability p that typical Cs are Ds”), coming
from the distributed semantics of probabilistic Description Logics. Additionally,
it embeds a set of cognitive heuristics for concept combination. We show that the
complexity of reasoning in our logic is EXPTIME-complete as in ALC
The Feasibility of Deriving the Electronic Frailty Index from Australian General Practice Records
Purpose: Frailty is a prevalent condition in older adults. Identification of frailty using an electronic Frailty Index (eFI) has been successfully implemented across general practices in the United Kingdom. However, in Australia, the eFI remains understudied. Therefore, we aimed to (i) examine the feasibility of deriving an eFI from Australian general practice records and (ii) describe the prevalence of frailty as measured by the eFI and the prevalence with socioeconomic status and geographic remoteness. Participants and Methods: This retrospective analysis included patients (≥70 years) attending any one of >700 general practices utilizing the Australian MedicineInsight data platform, 2017–2018. A 36-item eFI was derived using standard methodology, with frailty classified as mild (scores 0.13–0.24); moderate (0.25–0.36) or severe (≥0.37). Socioeconomic status (Socio-Economic Indexes for Areas (SEIFA) index)) and geographic remoteness (Australian Statistical Geography Standard (ASGC) remoteness areas) were also examined. Results: In total, 79,251 patients (56% female) were included, mean age 80.0 years (SD 6.5); 37.4% (95% CI 37.0–37.7) were mildly frail, 16.7% (95% CI 16.4–16.9) moderately frail, 4.8% (95% CI 4.7–5.0) severely frail. Median eFI score was 0.14 (IQR 0.08 to 0.22); maximum eFI score was 0.69. Across all age groups, moderate and severe frailty was significantly more prevalent in females (P < 0.001). Frailty severity increased with increasing age (P < 0.001) and was strongly associated with socioeconomic disadvantage (P < 0.001) but not with geographic remoteness. Conclusion: Frailty was identifiable from routinely collected general practice data. Frailty was more prevalent in socioeconomically disadvantaged groups, women and older patients and existed in all levels of remoteness. Routine implementation of an eFI could inform interventions to prevent or reduce frailty in all older adults, regardless of location
Freezing of Gait Detection in Parkinson's Disease: A Subject-Independent Detector Using Anomaly Scores
© 2012 IEEE. Freezing of gait (FoG) is common in Parkinsonian gait and strongly relates to falls. Current clinical FoG assessments are patients' self-report diaries and experts' manual video analysis. Both are subjective and yield moderate reliability. Existing detection algorithms have been predominantly designed in subject-dependent settings. In this paper, we aim to develop an automated FoG detector for subject independent. After extracting highly relevant features, we apply anomaly detection techniques to detect FoG events. Specifically, feature selection is performed using correlation and clusterability metrics. From a list of 244 feature candidates, 36 candidates were selected using saliency and robustness criteria. We develop an anomaly score detector with adaptive thresholding to identify FoG events. Then, using accuracy metrics, we reduce the feature list to seven candidates. Our novel multichannel freezing index was the most selective across all window sizes, achieving sensitivity (specificity) of 96% (79%). On the other hand, freezing index from the vertical axis was the best choice for a single input, achieving sensitivity (specificity) of 94% (84%) for ankle and 89% (94%) for back sensors. Our subject-independent method is not only significantly more accurate than those previously reported, but also uses a much smaller window (e.g., 3 s versus 7.5 s) and/or lower tolerance (e.g., 0.4 s versus 2 s)
Benefits of polidocanol endovenous microfoam (Varithena®) compared with physician-compounded foams
Objective: To compare foam bubble size and bubble size distribution, stability, and degradation rate of commercially
available polidocanol endovenous microfoam (Varithena) and physician-compounded foams using a number of laboratory tests.
Methods: Foam properties of polidocanol endovenous microfoam and physician-compounded foams were measured
and compared using a glass-plate method and a Sympatec QICPIC image analysis method to measure bubble size and
bubble size distribution, TurbiscanTM LAB for foam half time and drainage and a novel biomimetic vein model to measure
foam stability. Physician-compounded foams composed of polidocanol and room air, CO2, or mixtures of oxygen and
carbon dioxide (O2:CO2) were generated by different methods.
Results: Polidocanol endovenous microfoam was found to have a narrow bubble size distribution with no large
(>500 mm) bubbles. Physician-compounded foams made with the Tessari method had broader bubble size distribution
and large bubbles, which have an impact on foam stability. Polidocanol endovenous microfoam had a lower degradation
rate than any physician-compounded foams, including foams made using room air (p < 0.035). The same result was
obtained at different liquid to gas ratios (1:4 and 1:7) for physician-compounded foams. In all tests performed, CO2 foams
were the least stable and different O2:CO2 mixtures had intermediate performance. In the biomimetic vein model,
polidocanol endovenous microfoam had the slowest degradation rate and longest calculated dwell time, which represents the length of time the foam is in contact with the vein, almost twice that of physician-compounded foams using
room air and eight times better than physician-compounded foams prepared using equivalent gas mixes.
Conclusion: Bubble size, bubble size distribution and stability of various sclerosing foam formulations show that
polidocanol endovenous microfoam results in better overall performance compared with physician-compounded
foams. Polidocanol endovenous microfoam offers better stability and cohesive properties in a biomimetic vein model
compared to physician-compounded foams. Polidocanol endovenous microfoam, which is indicated in the United States
for treatment of great saphenous vein system incompetence, provides clinicians with a consistent product with enhanced
handling propertie
miR-96 regulates the progression of differentiation in mammalian cochlear inner and outer hair cells
MicroRNAs (miRNAs) are small noncoding RNAs able to regulate a broad range of protein-coding genes involved in many biological processes. miR-96 is a sensory organ-specific miRNA expressed in the mammalian cochlea during development. Mutations in miR-96 cause nonsyndromic progressive hearing loss in humans and mice. The mouse mutant diminuendo has a single base change in the seed region of the Mir96 gene leading to widespread changes in the expression of many genes. We have used this mutant to explore the role of miR-96 in the maturation of the auditory organ. We found that the physiological development of mutant sensory hair cells is arrested at around the day of birth, before their biophysical differentiation into inner and outer hair cells. Moreover, maturation of the hair cell stereocilia bundle and remodelling of auditory nerve connections within the cochlea fail to occur in miR-96 mutants. We conclude that miR-96 regulates the progression of the physiological and morphological differentiation of cochlear hair cells and, as such, coordinates one of the most distinctive functional refinements of the mammalian auditory system
Groupwise Multimodal Image Registration using Joint Total Variation
In medical imaging it is common practice to acquire a wide range of
modalities (MRI, CT, PET, etc.), to highlight different structures or
pathologies. As patient movement between scans or scanning session is
unavoidable, registration is often an essential step before any subsequent
image analysis. In this paper, we introduce a cost function based on joint
total variation for such multimodal image registration. This cost function has
the advantage of enabling principled, groupwise alignment of multiple images,
whilst being insensitive to strong intensity non-uniformities. We evaluate our
algorithm on rigidly aligning both simulated and real 3D brain scans. This
validation shows robustness to strong intensity non-uniformities and low
registration errors for CT/PET to MRI alignment. Our implementation is publicly
available at https://github.com/brudfors/coregistration-njtv
Electronic correlations in the iron pnictides
In correlated metals derived from Mott insulators, the motion of an electron
is impeded by Coulomb repulsion due to other electrons. This phenomenon causes
a substantial reduction in the electron's kinetic energy leading to remarkable
experimental manifestations in optical spectroscopy. The high-Tc
superconducting cuprates are perhaps the most studied examples of such
correlated metals. The occurrence of high-Tc superconductivity in the iron
pnictides puts a spotlight on the relevance of correlation effects in these
materials. Here we present an infrared and optical study on single crystals of
the iron pnictide superconductor LaFePO. We find clear evidence of electronic
correlations in metallic LaFePO with the kinetic energy of the electrons
reduced to half of that predicted by band theory of nearly free electrons.
Hallmarks of strong electronic many-body effects reported here are important
because the iron pnictides expose a new pathway towards a correlated electron
state that does not explicitly involve the Mott transition.Comment: 10 page
Prevalence of Disorders Recorded in Dogs Attending Primary-Care Veterinary Practices in England
Purebred dog health is thought to be compromised by an increasing occurence of inherited diseases but inadequate prevalence data on common disorders have hampered efforts to prioritise health reforms. Analysis of primary veterinary practice clinical data has been proposed for reliable estimation of disorder prevalence in dogs. Electronic patient record (EPR) data were collected on 148,741 dogs attending 93 clinics across central and south-eastern England. Analysis in detail of a random sample of EPRs relating to 3,884 dogs from 89 clinics identified the most frequently recorded disorders as otitis externa (prevalence 10.2%, 95% CI: 9.1-11.3), periodontal disease (9.3%, 95% CI: 8.3-10.3) and anal sac impaction (7.1%, 95% CI: 6.1-8.1). Using syndromic classification, the most prevalent body location affected was the head-and-neck (32.8%, 95% CI: 30.7-34.9), the most prevalent organ system affected was the integument (36.3%, 95% CI: 33.9-38.6) and the most prevalent pathophysiologic process diagnosed was inflammation (32.1%, 95% CI: 29.8-34.3). Among the twenty most-frequently recorded disorders, purebred dogs had a significantly higher prevalence compared with crossbreds for three: otitis externa (P = 0.001), obesity (P = 0.006) and skin mass lesion (P = 0.033), and popular breeds differed significantly from each other in their prevalence for five: periodontal disease (P = 0.002), overgrown nails (P = 0.004), degenerative joint disease (P = 0.005), obesity (P = 0.001) and lipoma (P = 0.003). These results fill a crucial data gap in disorder prevalence information and assist with disorder prioritisation. The results suggest that, for maximal impact, breeding reforms should target commonly-diagnosed complex disorders that are amenable to genetic improvement and should place special focus on at-risk breeds. Future studies evaluating disorder severity and duration will augment the usefulness of the disorder prevalence information reported herein
Cross-sectional analysis of a large cohort with X-linked Charcot-Marie-Tooth disease (CMTX1)
OBJECTIVE: To extend the phenotypic description of Charcot-Marie-Tooth disease (CMTX1) and to draw new genotype-phenotype relationships. METHODS: Mutations in GJB1 cause the main X-linked form of CMTX (CMTX1). We report cross-sectional data from 160 patients (from 120 different families, with 89 different mutations) seen at the Inherited Neuropathies Consortium centers. RESULTS: We evaluated 87 males who had a mean age of 41 years (range 10-78 years) and 73 females who had a mean age of 46 years (range 15-84 years). Sensory-motor polyneuropathy affects both sexes, more severely in males than in females, and there was a strong correlation between age and disease burden in males but not in females. Compared with females, males had more severe reduction in motor and sensory neurophysiology parameters. In contrast to females, the radial nerve sensory response in older males tended to be more severely affected compared with younger males. Median and ulnar nerve motor amplitudes were also more severely affected in older males, whereas ulnar nerve motor potentials tended to be more affected in older females. Conversely, there were no statistical differences between the sexes in other features of the disease, such as problems with balance and hand dexterity. CONCLUSIONS: In the absence of a phenotypic correlation with specific GJB1 mutations, sex-specific distinctions and clinically relevant attributes need to be incorporated into the measurements for clinical trials in people with CMTX1. CLINICALTRIALSGOV IDENTIFIER: NCT01193075
Regulation of Ubx Expression by Epigenetic Enhancer Silencing in Response to Ubx Levels and Genetic Variation
For gene products that must be present in cells at defined concentrations, expression levels must be tightly controlled to ensure robustness against environmental, genetic, and developmental noise. By studying the regulation of the concentration-sensitive Drosophila melanogaster Hox gene Ultrabithorax (Ubx), we found that Ubx enhancer activities respond to both increases in Ubx levels and genetic background. Large, transient increases in Ubx levels are capable of silencing all enhancer input into Ubx transcription, resulting in the complete silencing of this gene. Small increases in Ubx levels, brought about by duplications of the Ubx locus, cause sporadic silencing of subsets of Ubx enhancers. Ubx enhancer silencing can also be induced by outcrossing laboratory stocks to D. melanogaster strains established from wild flies from around the world. These results suggest that enhancer activities are not rigidly determined, but instead are sensitive to genetic background. Together, these findings suggest that enhancer silencing may be used to maintain gene product levels within the correct range in response to natural genetic variation
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