Prevalencia de Caries y Pérdida de Dientes en Población de 65 a 74 Años de Santiago, Chile

AbstractObjectivesTo measure prevalence of caries and tooth loss among low and middle-low socio-economic level elderly from Santiago, Chile.MethodsProportionate stratified probabilistic sampling techniques; sample of 109 people (74 women and 35 men) aged 65 to 74. Data gathered by means of a face-to-face questionnaire. Informed consent was obtained; individuals were examined by a calibrated dentist. The study was carried out from March to December 2008. Data analysis considered chi-square and ANOVA.ResultsDMFT was 24.9 (CI: 23.83; 25.96). All the individuals had caries experience; 45.9% had active caries lesions. The mean of non-treated active caries lesions was 0.9 per individual. Concerning prosthesis, 38.5% of individuals were found to use removable prosthesis and 15 people (13.76%) were edentulous.ConclusionsThe size of the gap and the importance of social environment on damaging oral health should lead to face this problem from a wider perspective of social determinants of health when building public policies

Effect of hydrothermal carbonization and torrefaction on spent coffee grounds

Received: February 1st, 2021 ; Accepted: March 28th, 2021 ; Published: April 6th, 2021 ; Correspondence: [email protected] is one of the most tradable commodities worldwide with the current global consumption of over 10 billion kilograms of coffee beans annually. At the same time, a significant amount of solid residues, which are known as spent coffee grounds (SCG), is generated during instant coffee manufacturing and coffee brewing. Those residues have a high potential in various applications, yet they remain mostly unutilized. The current work presents the experimental comparison of two pretreatment technologies - hydrothermal carbonization (HTC) and torrefaction - for converting SCG into a valuable char. The results showed that low-temperature torrefaction (< 250 °C) has a negligible effect on feedstock properties due to initial pre-processing of coffee beans. However, the energy conversion efficiency of torrefaction at higher temperatures is comparable with that of HTC. The average energy yields for high-temperature torrefaction (> 250 °C) and HTC were on the level of 88%. Devolatilization and depolymerization reactions reduce oxygen and increase carbon contents during both processes: chars after torrefaction at 300 °C and HTC at 240 °C had 23–28% more carbon and 43–46% less oxygen than the feedstock. Both pretreatment methods led to a comparable increase in energy density: the highest HHV of 31.03 MJ kg-1 for torrefaction at 300 °C and 32.33 MJ kg-1 for HTC at 240 °C, which is similar to HHV of anthracite. The results showed that both processes can be effectively used to convert SCG into energy-dense char, even though HTC led to slightly higher energy densification rates

Shannon Meets Carnot: Generalized Second Thermodynamic Law

The classical thermodynamic laws fail to capture the behavior of systems with energy Hamiltonian which is an explicit function of the temperature. Such Hamiltonian arises, for example, in modeling information processing systems, like communication channels, as thermal systems. Here we generalize the second thermodynamic law to encompass systems with temperature-dependent energy levels, $dQ=TdS+dT$, where $$ denotes averaging over the Boltzmann distribution and reveal a new definition to the basic notion of temperature. This generalization enables to express, for instance, the mutual information of the Gaussian channel as a consequence of the fundamental laws of nature - the laws of thermodynamics

Water Quality of the Poza Honda Dam and Other Water Points Down

The phenomenon of pollution of water basins is eliminating many potential water resources. Most of the pollution in Ecuador comes from household waste and agricultural chemicals, especially along the coast. One of the activities in the management of the water resource is the periodic monitoring of the bodies of water, being able to determine the different changes that occur and to influence through preventive actions that manage to reduce the pollution. The water resource is the articulating axis of all the activities in a territory and therefore of the populations that develop different productive activities that not only depend on the quantity and quality of this resource but also generate alterations to the natural state of the same. In the investigation, the monitoring of the quality of the water in different points of the Poza Honda dam and of the river Portoviejo is carried out. The study aims to manage the pollution processes that occur in the aquifer, due to the depositions of domestic, industrial and agricultural wastewater not controlled to be discharged

Self-assembly of binary nanoparticle dispersions: from square arrays and stripe phases to colloidal corrals

The generation of nanoscale square and stripe patterns is of major technological importance since they are compatible with industry-standard electronic circuitry. Recently, a blend of diblock copolymer interacting via hydrogen-bonding was shown to self-assemble in square arrays. Motivated by those experiments we study, using Monte Carlo simulations, the pattern formation in a two-dimensional binary mixture of colloidal particles interacting via isotropic core-corona potentials. We find a rich variety of patterns that can be grouped mainly in aggregates that self-assemble in regular square lattices or in alternate strips. Other morphologies observed include colloidal corrals that are potentially useful as surface templating agents. This work shows the unexpected versatility of this simple model to produce a variety of patterns with high technological potential.Comment: 13 pages, 5 figures, submitte