452 research outputs found
Don't bleach chaotic data
A common first step in time series signal analysis involves digitally
filtering the data to remove linear correlations. The residual data is
spectrally white (it is ``bleached''), but in principle retains the nonlinear
structure of the original time series. It is well known that simple linear
autocorrelation can give rise to spurious results in algorithms for estimating
nonlinear invariants, such as fractal dimension and Lyapunov exponents. In
theory, bleached data avoids these pitfalls. But in practice, bleaching
obscures the underlying deterministic structure of a low-dimensional chaotic
process. This appears to be a property of the chaos itself, since nonchaotic
data are not similarly affected. The adverse effects of bleaching are
demonstrated in a series of numerical experiments on known chaotic data. Some
theoretical aspects are also discussed.Comment: 12 dense pages (82K) of ordinary LaTeX; uses macro psfig.tex for
inclusion of figures in text; figures are uufile'd into a single file of size
306K; the final dvips'd postscript file is about 1.3mb Replaced 9/30/93 to
incorporate final changes in the proofs and to make the LaTeX more portable;
the paper will appear in CHAOS 4 (Dec, 1993
Evaluation of Intravascular Ultrasound Catheter Based Transducers using the Resolution Integral
An Assessment of the Imaging Performance of Hand-Held Ultrasound Scanners Using the Edinburgh Pipe Phantom
Objective: Although hand-held ultrasound devices (HHUSDs) are currently used for a diverse range of diagnostic and interventional applications the imaging performance of such scanners is rarely considered. The aim of this study was to assess the imaging performance of a wide-range of HHUSDs and compare their imaging performance to cart-based systems utilized for the same clinical applications. Methods: The grayscale imaging performances of 19 HHUSDs from eight different manufacturers, manufactured between 2016 and 2021, were measured using a figure-of-merit known as the resolution integral. The imaging performance of the HHUSDs were compared to 142 cart-based ultrasound scanners. Results: The HHUSD with the overall highest resolution integral (66) was a Butterfly (Burlington, MA, USA) wired phased array for small parts applications, followed by a Philips (Bothell, WA, USA) Lumify wired curvilinear transducer (57) for abdominal applications, a Butterfly wired phased array (56) for abdominal applications, a GE (Freiburg, Baden-Wurttemberg, Germany) VScan Air wireless linear array (56) for small parts applications, and a Healcerion (Seoul, Korea) Sonon 300L wireless linear array (56) for small parts applications. A GE VScan Extend wired phased array had the highest resolution integral (44) for cardiac applications. Conclusions: The Butterfly phased array had the highest resolution integral of all the 19 HHUSDs, although this value is still less than the majority of cart-based cardiac and abdominal ultrasound scanners manufactured from 2010 to 2017. Clinical users of HHUSDs should be mindful of the limitations in imaging performance of hand-held ultrasound devices.</p
Surveillance Tools Emerging From Search Engines and Social Media Data for Determining Eye Disease Patterns
ImportanceInternet-based search engine and social media data may provide a novel complementary source for better understanding the epidemiologic factors of infectious eye diseases, which could better inform eye health care and disease prevention.ObjectiveTo assess whether data from internet-based social media and search engines are associated with objective clinic-based diagnoses of conjunctivitis.Design, setting, and participantsData from encounters of 4143 patients diagnosed with conjunctivitis from June 3, 2012, to April 26, 2014, at the University of California San Francisco (UCSF) Medical Center, were analyzed using Spearman rank correlation of each weekly observation to compare demographics and seasonality of nonallergic conjunctivitis with allergic conjunctivitis. Data for patient encounters with diagnoses for glaucoma and influenza were also obtained for the same period and compared with conjunctivitis. Temporal patterns of Twitter and Google web search data, geolocated to the United States and associated with these clinical diagnoses, were compared with the clinical encounters. The a priori hypothesis was that weekly internet-based searches and social media posts about conjunctivitis may reflect the true weekly clinical occurrence of conjunctivitis.Main outcomes and measuresWeekly total clinical diagnoses at UCSF of nonallergic conjunctivitis, allergic conjunctivitis, glaucoma, and influenza were compared using Spearman rank correlation with equivalent weekly data on Tweets related to disease or disease-related keyword searches obtained from Google Trends.ResultsSeasonality of clinical diagnoses of nonallergic conjunctivitis among the 4143 patients (2364 females [57.1%] and 1776 males [42.9%]) with 5816 conjunctivitis encounters at UCSF correlated strongly with results of Google searches in the United States for the term pink eye (ρ, 0.68 [95% CI, 0.52 to 0.78]; P < .001) and correlated moderately with Twitter results about pink eye (ρ, 0.38 [95% CI, 0.16 to 0.56]; P < .001) and with clinical diagnosis of influenza (ρ, 0.33 [95% CI, 0.12 to 0.49]; P < .001), but did not significantly correlate with seasonality of clinical diagnoses of allergic conjunctivitis diagnosis at UCSF (ρ, 0.21 [95% CI, -0.02 to 0.42]; P = .06) or with results of Google searches in the United States for the term eye allergy (ρ, 0.13 [95% CI, -0.06 to 0.32]; P = .19). Seasonality of clinical diagnoses of allergic conjunctivitis at UCSF correlated strongly with results of Google searches in the United States for the term eye allergy (ρ, 0.44 [95% CI, 0.24 to 0.60]; P < .001) and eye drops (ρ, 0.47 [95% CI, 0.27 to 0.62]; P < .001).Conclusions and relevanceInternet-based search engine and social media data may reflect the occurrence of clinically diagnosed conjunctivitis, suggesting that these data sources can be leveraged to better understand the epidemiologic factors of conjunctivitis
De novo reefs: Fish habitat provision by oyster aquaculture varies with farming method
Aquaculture industries have the capacity to produce positive ecosystem service benefits, such as the provision of habitat to wild animals. Oyster cultivation is the oldest and largest aquaculture industry in south-eastern Australia. Oyster spat are grown to marketable size in rack-and-rail (‘racks’) or longline-and-basket (‘baskets’) configurations, which add structure to estuarine waters. This study assessed: (1) how the fish communities associated with oyster farms vary with production method; (2) how communities of fish utilise oyster infrastructure, as compared to adjacent natural habitats; and (3) whether oyster infrastructure can serve as de facto oyster reefs by supporting similar fish communities. Remote underwater video surveys, conducted during summer and winter of 2 study years, revealed that fish observations and species richness were generally greater for rack than basket cultivation. Both types of oyster farms supported at least as many species of fish as adjacent natural habitats, including oyster reef, seagrass, mangrove and bare sediment. Fish communities were, in general, most similar between racks and baskets and most dissimilar between racks and bare sediments. Oyster farms supported species of fish otherwise limited to habitats with wild oysters, and unique harvested fish species were observed more frequently at racks. Fish use of oyster-growing infrastructure for foraging and shelter mirrored use of natural biogenic habitats. Overall, this study suggests that the oyster aquaculture infrastructure can support fish communities with species composition similar to those of natural biogenic habitats, although this service is dependent on farming method. Ecosystem services provided by aquaculture should be considered in estuarine habitat enhancement, conservation and restoration
IFN-λ3, not IFN-λ4, likely mediates IFNL3-IFNL4 haplotype-dependent hepatic inflammation and fibrosis
Genetic variation in the IFNL3-IFNL4 (interferon-λ3-interferon-λ4) region is associated with hepatic inflammation and fibrosis. Whether IFN-λ3 or IFN-λ4 protein drives this association is not known. We demonstrate that hepatic inflammation, fibrosis stage, fibrosis progression rate, hepatic infiltration of immune cells, IFN-λ3 expression, and serum sCD163 levels (a marker of activated macrophages) are greater in individuals with the IFNL3-IFNL4 risk haplotype that does not produce IFN-λ4, but produces IFN-λ3. No difference in these features was observed according to genotype at rs117648444, which encodes a substitution at position 70 of the IFN-λ4 protein and reduces IFN-λ4 activity, or between patients encoding functionally defective IFN-λ4 (IFN-λ4-Ser70) and those encoding fully active IFN-λ4-Pro70. The two proposed functional variants (rs368234815 and rs4803217) were not superior to the discovery SNP rs12979860 with respect to liver inflammation or fibrosis phenotype. IFN-λ3 rather than IFN-λ4 likely mediates IFNL3-IFNL4 haplotype-dependent hepatic inflammation and fibrosis
High rate of drinking water contamination due to poor storage in squatter settlements in Mwanza, Tanzania
Background: Drinking water of acceptable quality is supposed to be free from faecal coliform and chemical substances that may be hazardous to human health. Water treatment and safe storage at the household level has been advocated as effective means of ensuring safe drinking water. This study was undertaken to determine the microbiological quality of the drinking water at household level in the squatter settlements in the city of Mwanza, Tanzania.Methods: A cross-sectional study was conducted between June 2014 and September 2014. A total of 15 randomly selected water sources (tap) and 207 households’ drinking water samples from these sources were studied to ascertain level of water contamination using Membrane Filtration Method. Pre-tested questionnaire was used to collect demographic and other data regarding water treatment and storage. Data were entered, cleaned and analysed using STATA Version 11.Results: All 15 samples from tap used as water sources were found to be free of indicator organism (Escherichia coli) while 109 (52.66%) of drinking water samples from 207 households were found to be contaminated with E. coli. All contaminated drinking water samples were from containers with no cover and spigot. Conclusions: There is a significant level of deterioration of water quality from the source to the drinking cup. Efforts to ensure quality storage methods for drinking water should be addressed at household level
Vaccination with Recombinant Microneme Proteins Confers Protection against Experimental Toxoplasmosis in Mice
Toxoplasmosis, a zoonotic disease caused by Toxoplasma gondii, is an important public health problem and veterinary concern. Although there is no vaccine for human toxoplasmosis, many attempts have been made to develop one. Promising vaccine candidates utilize proteins, or their genes, from microneme organelle of T. gondii that are involved in the initial stages of host cell invasion by the parasite. In the present study, we used different recombinant microneme proteins (TgMIC1, TgMIC4, or TgMIC6) or combinations of these proteins (TgMIC1-4 and TgMIC1-4-6) to evaluate the immune response and protection against experimental toxoplasmosis in C57BL/6 mice. Vaccination with recombinant TgMIC1, TgMIC4, or TgMIC6 alone conferred partial protection, as demonstrated by reduced brain cyst burden and mortality rates after challenge. Immunization with TgMIC1-4 or TgMIC1-4-6 vaccines provided the most effective protection, since 70% and 80% of mice, respectively, survived to the acute phase of infection. In addition, these vaccinated mice, in comparison to non-vaccinated ones, showed reduced parasite burden by 59% and 68%, respectively. The protective effect was related to the cellular and humoral immune responses induced by vaccination and included the release of Th1 cytokines IFN-γ and IL-12, antigen-stimulated spleen cell proliferation, and production of antigen-specific serum antibodies. Our results demonstrate that microneme proteins are potential vaccines against T. gondii, since their inoculation prevents or decreases the deleterious effects of the infection
Fluoroquinolone treatment and susceptibility of isolates from bacterial keratitis.
ObjectiveTo analyze the relationship between fluoroquinolone use at presentation and minimum inhibitory concentration in bacterial keratitis.MethodsThe Steroids for Corneal Ulcers Trial was a randomized, double-masked, placebo-controlled trial assessing the effect of adjunctive topical corticosteroid treatment on outcomes in bacterial keratitis. After presentation, all patients were treated with moxifloxacin hydrochloride, 0.5%. We compare antibiotic use at presentation with minimum inhibitory concentration against moxifloxacin for all isolates. Separate analyses accounted for organism species and fluoroquinolone generation.ResultsTopical fluoroquinolone use at presentation was reported in 92 of 480 cases (19.2%). Causative organisms in the 480 cases included Streptococcus pneumoniae (247 cases [51.5%]), Pseudomonas aeruginosa (109 cases [22.7%]), and Nocardia species (55 cases [11.5%]). Isolates from patients who reported fluoroquinolone use at presentation had a 2.01-fold-higher minimum inhibitory concentration (95% CI, 1.39-fold to 2.91-fold; P < .001). Fourth-generation fluoroquinolones were associated with a 3.48-fold-higher minimum inhibitory concentration than those isolates that were not exposed to pretreatment at enrollment (95% CI, 1.99-fold to 6.06-fold; P < .001).ConclusionThis study provides evidence that prior use of fluoroquinolones is associated with antibiotic resistance.Trial registrationclinicaltrials.gov Identifier: NCT00324168
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