A Number-Theoretic Error-Correcting Code

In this paper we describe a new error-correcting code (ECC) inspired by the Naccache-Stern cryptosystem. While by far less efficient than Turbo codes, the proposed ECC happens to be more efficient than some established ECCs for certain sets of parameters. The new ECC adds an appendix to the message. The appendix is the modular product of small primes representing the message bits. The receiver recomputes the product and detects transmission errors using modular division and lattice reduction

INFLUENCE OF THE TYPE OF OXIDANT IN THE COMBUSTION OF NATURAL GAS INSIDE AN ALUMINUM MELTING FURNACE

ABSTRACT The fuel used as energy source for aluminum melting is of extreme importance for a better performance of the process. However, the type of oxidant can also lead to better performance, leading to a greater preservation of the equipments. Air is more abundant and cheaper, however due to the presence of nitrogen, there is undesirable NOx formation. An alternative is to employ pure oxygen. Although it is more expensive, it can lead to a cleaner and much more efficient combustion process, by significantly altering the combustion aspects inside the furnace, such as the shape of the flame and the distribution of temperature and heat flux. In the present work, numerical simulations were carried out using the commercial package FLUENT, analyzing different cases with pure oxygen and air as the oxidant for the combustion of natural gas. The results showed the possible damages caused by the process if long or too intense and concentrated flames are present. Copyright © 2006 by ASME 2 INTRODUCTION There are several industrial combustion applications which may benefit from the use of oxygen-enriched air or pure oxygen as the oxidizer during the combustion process. The resulting effects are many. Oxygen enrichment increases the flame temperature, promotes oxidation, and can lead to smaller pollutant (NOx) emissions compared with hydrocarbon-air systems, due to the absence of nitrogen. The formation of nitrogen oxides (NOx) in air-feed combustion systems represents a significant source for this pollutant within the industrial sector. With the increase in the world-wide utilization of fossil fuels, the control of NOx emissions has become an issue of global concern. Additionally, with increasing oil prices, the use of lower quality fuels will worsen the problem. Advances in computational modeling tools and the increased performance of computers have made comprehensive modeling of NOx formation and destruction a valuable tool to provide insights and understanding of the NOx reaction processes in combustion systems. This technology has the potential to enhance the application of various combustion techniques used to reduce NOx emissions from practical combustion systems Numerical modeling has became an important tool in the design and optimization of industrial equipments and also in the prediction of the emission of pollutants such as CO (carbon monoxide), SOx (sulfur oxides), and NOx. Recently, several numerical studies In the work by Frassoldati et al. [2], the attention was focused on a new procedure, based on CFD, for the determination of NOx emissions from combustion processes, which allowed the use of very detailed reaction schemes. The predictions of NOx were obtained by post-processing the flow and temperature fields, as predicted by the CFD model, and lumping together computational cells similar in terms of NOx formation. The resulting macro-cells were assumed to be a network of ideal reactors, which were simulated adopting detailed kinetic mechanisms. Nieckele et al. [3] described a numerical simulation of the 100% oxy-firing combustion process inside an industrial aluminum re-melting reverb furnace. Three different configurations were analyzed including the comparison between the staged versus non-staged combustion processes. The numerical procedure was based on the finite volume formulation and the κ−ε model of turbulence. The combustion was modeled based on the finite rate models of Arrhenius and Magnussen, and the Discrete Transfer Radiation model was employed for predicting the radiation heat transfer. The numerical predictions allowed for the determination of the flame patterns, species concentration distribution, temperature and velocity fields

Adenosine metabolized from extracellular ATP promotes type 2 immunity through triggering A2BAR signaling in intestinal epithelial cells

Intestinal nematode parasites can cross the epithelial barrier, causing tissue damage and release of danger-associated molecular patterns (DAMPs) that may promote host protective type 2 immunity. We investigate whether adenosine binding to the A2B adenosine receptor (A2BAR) on intestinal epithelial cells (IECs) plays an important role. Specific blockade of IEC A2BAR inhibits the host protective memory response to the enteric helminth, Heligmosomoides polygyrus bakeri (Hpb), including disruption of gran-uloma development at the host-parasite interface. Memory T cell development is blocked during the primary response, and transcriptional analyses reveal profound impairment of IEC activation. Extracel-lular ATP is visualized 24 h after inoculation and is shown in CD39-deficient mice to be critical for the adenosine production mediating the initiation of type 2 immunity. Our studies indicate a potent adeno-sine-mediated IEC pathway that, along with the tuft cell circuit, is critical for the activation of type 2 immunity

The Flexibility of Nonconsciously Deployed Cognitive Processes: Evidence from Masked Congruence Priming

Background: It is well accepted in the subliminal priming literature that task-level properties modulate nonconscious processes. For example, in tasks with a limited number of targets, subliminal priming effects are limited to primes that are physically similar to the targets. In contrast, when a large number of targets are used, subliminal priming effects are observed for primes that share a semantic (but not necessarily physical) relationship with the target. Findings such as these have led researchers to conclude that task-level properties can direct nonconscious processes to be deployed exclusively over central (semantic) or peripheral (physically specified) representations. Principal Findings: We find distinct patterns of masked priming for "novel" and "repeated" primes within a single task context. Novel primes never appear as targets and thus are not seen consciously in the experiment. Repeated primes do appear as targets, thereby lending themselves to the establishment of peripheral stimulus-response mappings. If the source of the masked priming effect were exclusively central or peripheral, then both novel and repeated primes should yield similar patterns of priming. In contrast, we find that both novel and repeated primes produce robust, yet distinct, patterns of priming. Conclusions: Our findings indicate that nonconsciously elicited cognitive processes can be flexibly deployed over both central and peripheral representations within a single task context. While we agree that task-level properties can influence nonconscious processes, our findings sharply constrain the extent of this influence. Specifically, our findings are inconsistent with extant accounts which hold that the influence of task-level properties is strong enough to restrict the deployment of nonconsciously elicited cognitive processes to a single type of representation (i.e. central or peripheral).13 page(s

Unconsciously Triggered Conflict Adaptation

In conflict tasks such as the Stroop, the Eriksen flanker or the Simon task, it is generally observed that the detection of conflict in the current trial reduces the impact of conflicting information in the subsequent trial; a phenomenon termed conflict adaptation. This higher-order cognitive control function has been assumed to be restricted to cases where conflict is experienced consciously. In the present experiment we manipulated the awareness of conflict-inducing stimuli in a metacontrast masking paradigm to directly test this assumption. Conflicting response tendencies were elicited either consciously (through primes that were weakly masked) or unconsciously (strongly masked primes). We demonstrate trial-by-trial conflict adaptation effects after conscious as well as unconscious conflict, which could not be explained by direct stimulus/response repetitions. These findings show that unconscious information can have a longer-lasting influence on our behavior than previously thought and further stretch the functional boundaries of unconscious cognition

Fluorosis risk from early exposure to fluoride toothpaste

Swallowed fluoride toothpaste in the early years of life has been postulated to be a risk factor for fluorosis, but the epidemiological evidence is weakened by the fact that most of the relevant studies were done in developed countries where an individual is exposed to multiple sources of fluoride. Objectives: To quantify the risk of fluorosis from fluoride toothpaste in a population whose only potential source of fluoride was fluoride toothpaste. Methods: Case-control analyses were conducted to test the hypothesis that fluoride toothpaste use before the age of 6 years increased an individual's risk of fluorosis. Data came from a cross-sectional clinical dental examination of schoolchildren and a self-administered questionnaire to their parents. The study was conducted in Goa, India. The study group consisted of 1189 seventh grade children with a mean age of 12.2 years. Results: The prevalence of fluorosis was 12.9% using the TF index. Results of the crude, stratified, and logistic regression analyses showed that use of fluoride toothpaste before the age of 6 years was a risk indicator for fluorosis (OR 1.83, 95% CI 1.05–3.15). Among children with fluorosis, beginning brushing before the age of 2 years increased the severity of fluorosis significantly ( P < 0.001). Other factors associated with the use of fluoride toothpaste, such as eating or swallowing fluoride toothpaste and higher frequency of use, did not show a statistically significant increased risk for prevalence or severity of fluorosis. Conclusions: Fluoride toothpaste use before the age of 6 years is a risk indicator for fluorosis in this study population.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75437/1/j.1600-0528.1998.tb01957.x.pd

Automatic Top-Down Processing Explains Common Left Occipito-Temporal Responses to Visual Words and Objects

Previous studies have demonstrated that a region in the left ventral occipito-temporal (LvOT) cortex is highly selective to the visual forms of written words and objects relative to closely matched visual stimuli. Here, we investigated why LvOT activation is not higher for reading than picture naming even though written words and pictures of objects have grossly different visual forms. To compare neuronal responses for words and pictures within the same LvOT area, we used functional magnetic resonance imaging adaptation and instructed participants to name target stimuli that followed briefly presented masked primes that were either presented in the same stimulus type as the target (word–word, picture–picture) or a different stimulus type (picture–word, word–picture). We found that activation throughout posterior and anterior parts of LvOT was reduced when the prime had the same name/response as the target irrespective of whether the prime-target relationship was within or between stimulus type. As posterior LvOT is a visual form processing area, and there was no visual form similarity between different stimulus types, we suggest that our results indicate automatic top-down influences from pictures to words and words to pictures. This novel perspective motivates further investigation of the functional properties of this intriguing region