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Variability in Measures of Exhaled Breath Na+, Influence of Pulmonary Blood Flow and Salivary Na+
Courtney M. Wheatley, Nicholas A. Cassuto, William T. Foxx-Lupo and Eric M. Snyder
Clinical Medicine Insights: Circulatory, Respiratory and Pulmonary Medicine , 2012, DOI: 10.4137/CCRPM.S4718
Abstract: The assessment of inflammatory markers and ions in exhaled breath condensate (EBC) is being utilized more frequently in diseases such as asthma and cystic fibrosis with marked variability in EBC measures, including those of exhaled Na+. We sought to determine if variability in exhaled Na+ was due to differences in pulmonary blood flow (PBF) or Na+ in the mouth (salivary Na+). We measured exhaled Na+ three times with coinciding sampling of salivary Na+ and assessment of PBF (using acetylene rebreathing) in 13 healthy subjects (54% female, age = 27 ± 7 yrs., ht. = 172 ± 10 cm, wt. = 70 ± 21 kg, BMI = 22 ± 7 kg/m2 mean ± SD). Exhaled Na+ averaged 2.7 ± 1.2 mmol/l, and salivary Na+ averaged 5.51 ± 4.58 mmol/l. The coefficients of variation across all three measures in all 13 subjects averaged 30% for exhaled Na+ and 83% for salivary Na+, within subjects the variability across the three measures averaged 30% for exhaled Na+ and 38% for salivary Na+. Across all three measures in all 13 subjects the relationship between PBF and exhaled Na+ averaged 0.027 (P = 0.87), and the relationship between salivary Na+ and exhaled Na+ concentrations averaged 0.59 (P = 0.001). Also, we sought to determine the relationship between exhaled Na+ and serum Na+ in an addition 20 subjects. There was a moderate and significant relationship between serum Na+ and exhaled Na+ (r = 0.37, P = 0.04). These findings suggest there that the variability in exhaled Na+ is caused, at least in part, by droplet formation from within the mouth as turbulent air passes through and that there is a flux of ions from the pulmonary blood into the airways.
The RR interval spectrum, the ECG signal and aliasing
A. Gersten,O. Gersten,A. Ronen,Y. Cassuto
Physics , 1999,
Abstract: A reliable spectral analysis requires sampling rate at least twice as large as the frequency bound, otherwise the analysis will be unreliable and plagued with aliasing distortions. The RR samplings do not satisfy the above requirements and therefore their spectral analysis might be unreliable. In order to demonstrate the feasibility of aliasing in RR spectral analysis, we have done an experiment which have shown clearly how the aliasing was developed. In the experiments, one of us (A.G) had kept his high breathing rate constant with the aid of metronome for more than 5 minutes. The breathing rate was larger than one-half the heart rate. Very accurate results were obtained and the resulting aliasing well understood. To our best knowledge this is the first controlled experiment of this kind coducted on humans. We compared the RR spectral analysis with the spectrum of the ECG signals from which the RR intervals were extracted. In the significant for RR analysis frequencies (below one-half Hertz) significant differences were observed. In conclusion we recommend to study the spectral analysis of the ECG signal in the free of aliasing frequency range.
Iterative Decoding of LDPC Codes over the q-ary Partial Erasure Channel
Rami Cohen,Yuval Cassuto
Mathematics , 2015,
Abstract: In this paper, we develop a new channel model, which we name the q-ary partial erasure channel (QPEC). The QPEC has a q-ary input, and its output is either one symbol or a set of M symbols, where M may be smaller than q. This channel serves as a generalization to the binary erasure channel (BEC), and mimics situations when a symbol output from the channel is known only partially; that is, the output symbol contains some ambiguity, but is not fully erased. This type of channel is motivated by non-volatile memory multi-level read channels. In such channels the readout is obtained by a sequence of current/voltage measurements, which may terminate with partial knowledge of the stored level. Our investigation is concentrated on the performance of low-density parity-check (LDPC) codes when used over this channel, thanks to their low decoding complexity using belief propagation. We provide the density-evolution equations that describe the decoding process, and suggest several bounds and approximations. In addition, we provide tools for the practical design of LDPC codes for use over the QPEC.
Algorithms and Throughput Analysis for MDS-Coded Switches
Rami Cohen,Yuval Cassuto
Mathematics , 2015,
Abstract: Network switches and routers need to serve packet writes and reads at rates that challenge the most advanced memory technologies. As a result, scaling the switching rates is commonly done by parallelizing the packet I/Os using multiple memory units. For improved read rates, packets can be coded with an [n,k] MDS code, thus giving more flexibility at read time to achieve higher utilization of the memory units. In the paper, we study the usage of [n,k] MDS codes in a switching environment. In particular, we study the algorithmic problem of maximizing the instantaneous read rate given a set of packet requests and the current layout of the coded packets in memory. The most interesting results from practical standpoint show how the complexity of reaching optimal read rate depends strongly on the writing policy of the coded packets.
LDPC Codes for Partial-Erasure Channels in Multi-Level Memories
Rami Cohen,Yuval Cassuto
Computer Science , 2014,
Abstract: In this paper, we develop a new channel model, which we name the $q$-ary partial erasure channel (QPEC). QPEC has a $q$-ary input, and its output is either one symbol or a set of $M$ possible values. This channel mimics situations when current/voltage levels in measurement channels are only partially known, due to high read rates or imperfect current/voltage sensing. Our investigation is concentrated on the performance of low-density parity-pheck (LDPC) codes when used over this channel, due to their low decoding complexity with iterative-decoding algorithms. We give the density evolution equations of this channel, and develop its decoding-threshold analysis. Part of the analysis shows that finding the exact decoding threshold efficiently lies upon a solution to an open problem in additive combinatorics. For this part we give bounds and approximations.
Accurately Measuring Inspection Time with Computers  [PDF]
A. Kym Preiss, Nicholas R. Burns
International Journal of Intelligence Science (IJIS) , 2012, DOI: 10.4236/ijis.2012.24013
Abstract: Accurately measuring inspection time (IT) with computers requires several considerations. They are: 1) Screen redraw period; 2) Synchronous and timely image presentation; 3) Stimulus duration timing; 4) Image scale invariance; 5) Stan dardized presentation format (of which image scale invariance is a part). The first consideration dictates a minimum duration available for measuring IT. The second and third are necessary for accurate stimulus duration. The fourth is necessary to provide scale invariant images, that is, images with the same visual angle at a given viewing distance on any computer. And the fifth ensures that participants everywhere respond to the same task. Our computer program em bodies these elements and we make it freely available to any interested party. Data to establish validity and reliability are presented, and normative data on 2518 participants aged 6 to 92 years are available.
Effects of cyclosporine A pretreatment of deceased organ donors on kidney graft function (Cis-A-rein): study protocol for a randomized controlled trial
Carole Ichai,Elisabeth Cassuto,Eric Fontaine,Jean-Christophe Orban,Jean-Michel Constantin,Karine Baumstarck,Marc Leone,for the AzuRéa network
- , 2018, DOI: 10.1186/s13063-018-2597-4
Abstract:
Fountain Codes with Nonuniform Selection Distributions through Feedback
Morteza Hashemi,Yuval Cassuto,Ari Trachtenberg
Mathematics , 2015,
Abstract: One key requirement for fountain (rateless) coding schemes is to achieve a high intermediate symbol recovery rate. Recent coding schemes have incorporated the use of a feedback channel to improve intermediate performance of traditional rateless codes; however, these codes with feedback are designed based on uniformly at random selection of input symbols. In this paper, on the other hand, we develop feedback-based fountain codes with dynamically-adjusted nonuniform symbol selection distributions, and show that this characteristic can enhance the intermediate decoding rate. We provide an analysis of our codes, including bounds on computational complexity and failure probability for a maximum likelihood decoder; the latter are tighter than bounds known for classical rateless codes. Through numerical simulations, we also show that feedback information paired with a nonuniform selection distribution can highly improve the symbol recovery rate, and that the amount of feedback sent can be tuned to the specific transmission properties of a given feedback channel.
Age
Hanoch Cassuto,Itai Berger,Ortal Slobodin
- , 2018, DOI: 10.1177/1087054715575066
Abstract: Objective: This study investigated age-related changes in sustained attention in children with ADHD and in their typically developed peers. Method: The study used a Continuous Performance Test (CPT) that includes visual and auditory stimuli serving as distractors. The rate of omission errors was used as a measurement of difficulty in sustained attention. Participants were children and adolescents aged 7 to 18 years (478 with ADHD and 361 without ADHD). Results: Both groups of adolescents (with and without ADHD) showed reduced distractibility than younger children from the same group. However, distractibility tended to diminish in non-ADHD adolescents, but not in adolescents with ADHD. Conclusion: Although part of the difficulties in ADHD could be explained by developmental delay that improves with time, other deficits, such as increased distractibility causing more omission errors, do not show a clear developmental trajectory. The results suggest that deficits in inhibitory control might be the core of ADHD
Disinfection of the hospital water supply: a hidden risk to dialysis patients
Nicholas A Hoenich
Critical Care , 2009, DOI: 10.1186/cc8158
Abstract: The article by Bek and colleagues [1] in the previous issue of Critical Care raises an important and frequently unrecognised issue concerned with haemodialysis in a hospital setting. Renal services in hospitals frequently derive their water supply from the hospital water distribution network. Such networks are complex, can contain regions of low flow or stagnation, and frequently incorporate a storage tank to ensure adequate water pressure and availability of supply in times of peak demand. In common with any water distribution network, those in the hospital are subject to biofilm formation. A number of pathogens (for example, Legionella, pseudomonas, and mycobacteria) thrive in the biofilm and may be up to 3,000 times more resistant to bacteriostats added to the public water supply than their free-floating counterparts [2,3].To minimise risk from nosocomial infections, hospitals employ a range of preventive strategies to control the formation of biofilm, including the use of chemical agents such as silver-stabilised hydrogen peroxide [4,5]. Hydrogen peroxide is an oxidising agent, which at concentrations used for disinfection is considered safe to drink, enabling it to be used in 'live' buildings, and is eco-friendly since it breaks down to water and oxygen. Its effectiveness and stability can be enhanced by the addition of trace amounts of silver (silver-stabilized hydrogen peroxide).For dialysis applications, the unsuitability of drinking water has long been recognised and water for use in dialysis units undergoes additional treatment to reduce contaminant levels to below that specified in national or international standards dealing with water for use in dialysis [6]. Although the design of the water treatment plants used in dialysis units is dependent upon the quality of the feed or raw water and the uses that the treated water is put to within the dialysis unit (conventional haemodialysis, reprocessing of dialysers, or the production of infusate for 'on-line' t
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