Simple model for the phase coexistence and electrical conductivity of alkali fluids

We report the first theoretical model for the alkali fluids which yields a liquid-vapor phase coexistence with the experimentally observed features and electrical conductivity estimates which are also in accord with observations. We have carried out a Monte Carlo simulation for a lattice gas model which allows an integrated study of the structural, thermodynamic, and electronic properties of metal-atom fluids. Although such a technique is applicable to both metallic and nonmetallic fluids, non-additive interactions due to valence electron delocalization are a crucial feature of the present model.Comment: RevTex, 11 pages, 2 ps figure files appended, submitted to PR

Study of theoretical models for the liquid-vapor and metal-nonmetal transitions of alkali fluids

Theoretical models for the liquid-vapor and metal-nonmetal transitions of alkali fluids are investigated. Mean-field models are considered first but shown to be inadequate. An alternate approach is then studied in which each statistical configuration of the material is treated as inhomogeneous, with the energy of each ion being determined by its local environment. Nonadditive interactions, due to valence electron delocalization, are a crucial feature of the model. This alternate approach is implemented within a lattice-gas approximation which takes into account the observed mode of expansion in the materials of interest and which is able to treat the equilibrium density fluctuations. We have carried out grand canonical Monte Carlo simulations, for this model, which allow a unified, self-consistent, study of the structural, thermodynamic, and electronic properties of alkali fluids. Applications to Cs, Rb, K, and Na yield results in good agreement with observations.Comment: 13 pages, REVTEX, 10 ps figures available by e-mail

Own-price, cross-price, and expenditure elasticities on sugar-sweetened beverages in Guatemala

BACKGROUND:The obesity epidemic is spreading rapidly in Guatemala, a low/middle income country still struggling with undernutrition. Sugar sweetened beverages (SSBs) consumption is strongly associated with overweight, obesity, and non-communicable diseases. In Guatemala, SSBs are readily available and consumption is high, particularly among adolescents. SSB taxes have been proposed as a cost-effective way to reduce consumption and generate revenues for public health, as has been demonstrated in several countries around the world. OBJECTIVE:To estimate the price, expenditure, quality, and cross-price elasticity of beverage demand using household survey data. METHOD:We conducted a secondary analysis on the 2014 Guatemala Living Conditions National Survey that includes national representative household data on expenditure. Own price, expenditure, quality, and cross-price elasticities of milk, soft drinks, packaged juices, and bottled water were estimated using Deaton's Almost Ideal Demand System (AIDS), controlling for goods' quality. Household characteristics and beverage expenditure are summarized for urban and rural locations using descriptive statistics. RESULTS:Positive expenditure on soft drinks was highest (50.9% of households). Positive expenditure on bottled water was next for urban households (43.8%) and lowest for rural households (10.8%). Own-price elasticities for all beverages are negative and statistically significant. Own-price elasticity of soft drinks is -1.39, suggesting that with a 10% increase in price, consumption would decrease by 13.9%. Expenditure elasticity for soft drinks (0.99) suggests that a 10% household expenditure increase would result in a 9.9% increase in demand. Milk (0.07) and soft drinks (0.07) have positive quality elasticity implying that, as household total expenditure increases, the quality of these beverages, measured by their unit values, also increases. CONCLUSION:Soft drink demand is highly sensitive to changes in prices, suggesting that SSB taxes could significantly reduce consumption, which, in turn, could contribute to curbing the overweight/obesity epidemic

Error Prevention in Sensors and Sensor Systems

Achievements in all fields of engineering and fabrication methods have led towards optimization and integration of multiple sensing devices into a concise system. These advances have caused significant innovation in various commercial, industrial, and research efforts. Integrations of subsystems have important applications for sensor systems in particular. The need for reporting and real time awareness of a device’s condition and surroundings have led to sensor systems being implemented in a wide variety of fields. From environmental sensors for agriculture, to object characterization and biomedical sensing, the application for sensor systems has impacted all modern facets of innovation. With these innovations, however, additional sources of errors can occur, that can cause new but exciting challenges for such integrated devices. Such challenges range from error correction and accuracy to power optimization. Researchers have invested significant time and effort to improve the applicability and accuracy of sensors and sensor systems. Efforts to reduce inherent and external noise of sensors can range from hardware to software solutions, focusing on signal processing and exploiting the integration of multiple signals and/or sensor types. My research work throughout my career has been focused on deployable and integrated sensor systems. Their integration not only in hardware and components but also in software, machine learning, pattern recognition, and overall signal processing algorithms to aid in error correction and noise tailoring in all their hardware and software components

A cross-linguistic database of phonetic transcription systems

Contrary to what non-practitioners might expect, the systems of phonetic notation used by linguists are highly idiosyncratic. Not only do various linguistic subfields disagree on the specific symbols they use to denote the speech sounds of languages, but also in large databases of sound inventories considerable variation can be found. Inspired by recent efforts to link cross-linguistic data with help of reference catalogues (Glottolog, Concepticon) across different resources, we present initial efforts to link different phonetic notation systems to a catalogue of speech sounds. This is achieved with the help of a database accompanied by a software framework that uses a limited but easily extendable set of non-binary feature values to allow for quick and convenient registration of different transcription systems, while at the same time linking to additional datasets with restricted inventories. Linking different transcription systems enables us to conveniently translate between different phonetic transcription systems, while linking sounds to databases allows users quick access to various kinds of metadata, including feature values, statistics on phoneme inventories, and information on prosody and sound classes. In order to prove the feasibility of this enterprise, we supplement an initial version of our cross-linguistic database of phonetic transcription systems (CLTS), which currently registers five transcription systems and links to fifteen datasets, as well as a web application, which permits users to conveniently test the power of the automatic translation across transcription systems

Some remarks on particle size effects on the abrasion of a range of Fe based alloys

The low-stress three body abrasion behaviour of a range of steels was investigated. The tests were carried out in a rubber wheel tester (according to ASTM G65-94, reapproved in 2000) at room temperature. The abrasive particles used were angular alumina particles of four different sizes. The results showed that, in general, the smaller particles (50 8m and 125 8m average size) caused more damage. With these particles, observations of surface morphology indicarted a more intense cutting and ploughing action, leading to more damage, whereas bigger particles i.e. larger 250 8m and 560 8m particles produced less damage, and their action involved more plastic deformation type wear. The 304 SS had a lower abrasion resistance than the 310 SS. For the austentic and ferritic steels the subsurface deformation was larger for impact with the coarser particles. Variations in substrate hardness had no effect on the abrasive behaviour observed. On the whole, the hardest steel (mild steel in martensitic condition) showed the higher extent of damage, irrespective of particle size

RNA-binding protein Elavl1/HuR is required for maintenance of cranial neural crest specification

Neural crest development is transcriptionally controlled via sequential activation of gene regulatory networks (GRNs). Recent evidence increasingly implicates a role for post-transcriptional regulation in modulating the output of these regulatory circuits. Using RNA-sequencing data from avian embryos to identify potential post-transcriptional regulators, we observed enrichment during early neural crest development of Elavl1, which encodes for the RNA-binding protein HuR. Immunohistochemical analyses revealed expression of HuR following establishment of the neural plate border. Perturbation of HuR resulted in premature neural crest delamination from the neural tube as well as significant reduction in transcripts associated with the neural crest specification GRN (Axud1 and FoxD3), phenotypes also observed with downregulation of the canonical Wnt inhibitor Draxin. RNA pulldown further shows that Draxin is a specific target of HuR. Importantly, overexpression of exogenous Draxin was able to rescue the cranial neural crest specification defects observed with HuR knockdown. Thus, HuR plays a critical a role in the maintenance of cranial neural crest specification, at least partially via Draxin mRNA stabilization. Together, these data highlight an important intersection of post-transcriptional regulation with modulation of the neural crest specification GRN

RNA-binding protein Elavl1/HuR is required for maintenance of cranial neural crest specification

Neural crest development is transcriptionally controlled via sequential activation of gene regulatory networks (GRNs). Recent evidence increasingly implicates a role for post-transcriptional regulation in modulating the output of these regulatory circuits. Using RNA-sequencing data from avian embryos to identify potential post-transcriptional regulators, we observed enrichment during early neural crest development of Elavl1, which encodes for the RNA-binding protein HuR. Immunohistochemical analyses revealed expression of HuR following establishment of the neural plate border. Perturbation of HuR resulted in premature neural crest delamination from the neural tube as well as significant reduction in transcripts associated with the neural crest specification GRN (Axud1 and FoxD3), phenotypes also observed with downregulation of the canonical Wnt inhibitor Draxin. RNA pulldown further shows that Draxin is a specific target of HuR. Importantly, overexpression of exogenous Draxin was able to rescue the cranial neural crest specification defects observed with HuR knockdown. Thus, HuR plays a critical a role in the maintenance of cranial neural crest specification, at least partially via Draxin mRNA stabilization. Together, these data highlight an important intersection of post-transcriptional regulation with modulation of the neural crest specification GRN