159 research outputs found
Constructive aspects of Riemann's permutation theorem for series
The notions of permutable and weak-permutable convergence of a series
of real numbers are introduced. Classically, these
two notions are equivalent, and, by Riemann's two main theorems on the
convergence of series, a convergent series is permutably convergent if and only
if it is absolutely convergent. Working within Bishop-style constructive
mathematics, we prove that Ishihara's principle \BDN implies that every
permutably convergent series is absolutely convergent. Since there are models
of constructive mathematics in which the Riemann permutation theorem for series
holds but \BDN does not, the best we can hope for as a partial converse to our
first theorem is that the absolute convergence of series with a permutability
property classically equivalent to that of Riemann implies \BDN. We show that
this is the case when the property is weak-permutable convergence
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Per- and Polyfluoroalkyl Substances (PFAS) in Environmental Air-Water Matrices and Light Non-Aqueous Phase Liquids (LNAPL)
The presence of per- and polyfluoroalkyl substances (PFAS), organic contaminants first synthesized in the 1940s, has been reported worldwide in a variety of environmental matrices and ultimately in biological systems including humans. Ongoing research into PFAS has included identifying novel PFAS, assessing their fate and transport in the environment, and identifying exposure routes. These topics ultimately allow risk assessments and remediation efforts to commence.
In Chapter 2, a method was developed to analyze for PFAS in naturally-occurring foams on a freshwater lake by liquid chromatography time-of-flight mass spectrometry (LC-QToF). Concentrations in the foam were compared to the underlying bulk water to generate enrichment factors. Select samples were analyzed by 1H NMR to characterize the functional group composition in the foam and bulk water. Enrichment in the foam was correlated with the relative hydrophobicities of the individual PFAS, as well as increased enrichment for linear isomers when compared to branched isomers. The foam and bulk water were also characterized for dissolved organic carbon (DOC), of which the PFAS comprised <0.1% of the overall DOC. This was the first published work quantifying PFAS in naturally-occurring foam and suggested the DOC as the overall driver of foam that provides an enrichment mechanism for foam.
In Chapter 3, existing methods for sampling the surface microlayer (SML) were deployed on a PFAS-impacted lake to determine the optimal approach for sampling of the microlayer with respect to PFAS. The accuracy, precision, and limits of quantification were used to support a recommendation of the sampling techniques. The PFAS enrichment in the microlayer was compared to PFAS enrichment in open ocean SMLs, foam, and sea-spray aerosols. The precision of the methods was then used to assess SML variability on the 1m scale and the sampling site (km) scale. Finally, for PFAS enriched in the SML, interfacial partitioning coefficients were generated for the first time using field data.
In Chapter 4, a novel method was developed for quantifying PFAS in light non-aqueous phase liquids (LNAPL). A micro liquid-liquid extraction prepared samples to be analyzed by LC-QToF for 50 targets and up to 800 suspect PFAS. A novel quantitation technique was used to estimate concentrations for suspect PFAS, which do not have analytical standards. This method was used to analyze 17 field LNAPL samples. The PFAS found in LNAPL samples indicates that LNAPL may serve as a long-term source of PFAS and sites with PFAS and LNAPL contamination may require further characterization
Grid enabled high throughput virtual screening against four different targets implicated in malaria
PCSVInternational audienceAfter having deployed a first data challenge on malaria and a second one on avian flu, respectively in summer 2005 and spring 2006, we are demonstrating here again how efficiently the computational grids can be used to produce massive docking data at a high-throughput. During more than 2 months and a half, we have achieved at least 140 million dockings, representing an average throughput of almost 80,000 dockings per hour. This was made possible by the availability of thousands of CPUs through different infrastructures worldwide. Through the acquired experience, the WISDOM production environment is evolving to enable an easy and fault-tolerant deployment of biological tools; in this case it is the FlexX commercial docking software which is used to dock the whole ZINC database against 4 different targets
Real-World Implementation of Infant Behavioral Sleep Interventions: Results of a Parental Survey
Objective
To describe parental practices implementing behavioral sleep intervention (BSI) outside a clinical setting.
Study design
Parents (nâ=â652), recruited through a Facebook group designed as a peer support group for parents using BSI, completed an online survey about their experience using BSI with their infant or toddler.
Results
On average, parents implemented BSI when their infant was 5.6 (±2.77) months. Parents most often used modified (49.5%) or unmodified extinction (34.9%), with fewer using a parental presence approach (15.6%). Regardless of BSI type, more parents endorsed âa great deal of stressâ during the first night (42.2%) than 1 week later (5.2%). The duration of infant crying was typically greatest the first night (reported by 45%; Mâ=â43 minutes) and was significantly reduced after 1 week (Mâ=â8.54 minutes). Successful implementation of BSI on the first attempt was reported by 83%, with a median and mode of 7 days until completion (79% by 2 weeks). Regardless of BSI type, after intervention parents reported their infant had less difficulty falling asleep, fewer night awakenings, and were more likely to sleep in their room and/or in their own crib/bed.
Conclusions
The majority of parents report successfully implementing BSI, with significantly reduced infant crying by the end of 1 week and success within 2 weeks. Few differences were found between behavioral approaches
Sibling sleep-What can it tell us about parental sleep reports in the context of autism?
Sleep problems are common in families raising children with Autism Spectrum Disorder (ASD). Clinicians often depend on parent reports of child sleep but minimal research exists to address the accuracy or biases in these reports. To isolate parent-report accuracy (from differences in sleep behaviors), the sleep of younger siblings were assessed within a two-group design. The present study compared parent diary reports of infant sibling sleep to videosomnography and actigraphy. In the high-risk group, families had at least one child with ASD and a younger sibling (n = 33). The low-risk comparison group had no family history of ASD (n = 42). We confirmed comparable sleep behaviors between the groups and used paired t tests, two-one-sided-tests (TOST), and Bland-Altman plots to assess parent report accuracy. The parameters of sleep onset, nighttime sleep duration, awakenings, morning rise time, and daytime sleep duration were evaluated. Diary and videosomnography estimates were comparable for nighttime sleep duration, morning rise time, and awakenings for both groups. Diary and actigraph estimates were less comparable for both groups. Daytime sleep duration estimates had the largest discrepancy with both groups reporting (on average) 40 additional minutes of sleep when compared to actigraphy estimates. In the present study, families raising children with ASD were just as accurate as other families when reporting infant sleep behaviors. Our findings have direct clinical implications and support the use of parent nighttime sleep reports
Les grilles pour le développement médical
PCSV, prĂ©sentĂ© par V. Breton, Ă paraĂźtre dans les Comptes-Rendu de la ConfĂ©renceLe dĂ©veloppement rĂ©cent des sciences et technologies de l'information et de la communication permet aujourd'hui la crĂ©ation de vĂ©ritables infrastructures pour le calcul et le stockage de donnĂ©es hĂ©tĂ©rogĂšnes Ă l'Ă©chelle rĂ©gionale, nationale et internationale. Ces infrastructures, appelĂ©es grilles informatiques, permettront bientĂŽt d'utiliser les ressources informatiques mutualisĂ©es avec autant de facilitĂ© que nous utilisons aujourd'hui l'Ă©lectricitĂ©. L'utilisation des grilles afin d'accĂ©lĂ©rer la dĂ©couverte de mĂ©dicaments est une voie trĂšs prometteuse pour l'avenir. Par cette approche in silico, le nombre de molĂ©cules ainsi que la vitesse de test peuvent ĂȘtre grandement augmentĂ©s induisant un coĂ»t moindre de dĂ©veloppement de mĂ©dicaments. Du 11 Juillet au 31 AoĂ»t 2005, l'expĂ©rience WISDOM (Wide In Silico Docking On Malaria) a permis de tester rien moins qu'un million de ligands (mĂ©dicaments potentiels) pour le traitement du paludisme: 1700 ordinateurs Ă travers le monde ont ainsi Ă©tĂ© associĂ©s Ă cette dĂ©marche permettant de rĂ©aliser en un mois ce qui aurait nĂ©cessitĂ© 80 ans sur un ordinateur classique. L'analyse des rĂ©sultats est en cours. Par cette approche, on peut souhaiter Ă©galement que les maladies orphelines puissent bĂ©nĂ©ficier d'un intĂ©rĂȘt nouveau de la part des industries pharmaceutiques, Ă travers notamment la baisse du coĂ»t de dĂ©veloppement d'un mĂ©dicament, principal obstacle actuellement Ă leur mobilisation
Pediatric Videosomnography: Can Signal/Video Processing Distinguish Sleep and Wake States?
The term videosomnography captures a range of video-based methods used to record and subsequently score sleep behaviors (most commonly sleep vs. wake states). Until recently, the time consuming nature of behavioral videosomnography coding has limited its clinical and research applications. However, with recent technological advancements, the use of auto-videosomnography techniques may be a practical and valuable extension of behavioral videosomnography coding. To test an auto-videosomnography system within a pediatric sample, we processed 30 videos of infant/toddler sleep using a series of signal/video-processing techniques. The resulting auto-videosomnography system provided minute-by-minute sleep vs. wake estimates, which were then compared to behaviorally coded videosomnography and actigraphy. Minute-by-minute estimates demonstrated moderate agreement across compared methods (auto-videosomnography with behavioral videosomnography, Cohen's kappa = 0.46; with actigraphy = 0.41). Additionally, auto-videosomnography agreements exhibited high sensitivity for sleep but only about half of the wake minutes were correctly identified. For sleep timing (sleep onset and morning rise time), behavioral videosomnography and auto-videosomnography demonstrated strong agreement. However, nighttime waking agreements were poor across both behavioral videosomnography and actigraphy comparisons. Overall, this study provides preliminary support for the use of an auto-videosomnography system to index sleep onset and morning rise time only, which may have potential telemedicine implications. With replication, auto-videosomnography may be useful for researchers and clinicians as a minimally invasive sleep timing assessment method
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