Synthesis, Textural and Structural Properties of Calcium Hydroxide Nanoparticles in Hydro-Alcoholic Suspension

The use of calcium hydroxide nanoparticles (nanolime) in hydro-alcoholic suspensions represents a good enhancement in particular in the conservation of stones and surfaces of interest in Cultural Heritage. In this work we have produced nanolime by using our alternative method of synthesis (based on the use of a surfactant agent in the original solution) and we have studied, for the first time, structural and morphological properties of the synthesized nanoparticles directly in hydro-alcoholic suspension by synchrotron X-ray diffraction technique and transmission electron micro-scope observations. The particles characterization was performed on suspensions synthesized by varying surfactant content in the synthesis procedure and the water/alcohol ratio, too. We have found that only pure and crystalline Ca(OH)2 particles produced during the synthesis procedure and they maintained stably in suspension. These particles were hexagonally plated and regularly shaped with side dimension ranging from 300 to 40 nm or less;they had a platy habit and they presented, particularly with high alcohol content in suspension, a preferred orientation along z-axis.

Central obesity in Yemeni children: A population based cross-sectional study

AIM: To establish percentile curves and to explore prevalence and correlates of central obesity among Yemeni children in a population based cross-sectional study.METHODS: A representative sample of 3114 Yemeni children(1564 boys,1550 girls) aged 6-19 years participating in the HYpertension and Diabetes in Yemen study was studied.Data collection was conducted at home by survey teams composed of two investigators of both genders.Study questionnaire included questions about demographics,lifestyle,and medical history.Anthropometric measurements included body weight,height,waist circumference(WC) and hip circumferences.Waist to hip ratio(WHR) and waist-toheight ratio(WHtR) were then calculated.Age and gender specific smoothed percentiles of WC,WHR,and WHtR were obtained using lambda-mu-sigma parameters(LMS method).The independent predictors of central obesity defined as(1) WC percentile ≥ 90th;(2) WHtR ≥ 0.5;or(3) WC percentile ≥ 90thand WHtR ≥ 0.5,were identified at multivariate logistic regression analysis adjusted for age,gender,urban/rural location,years of school education,sedentary/active life-style.RESULTS: Percentile curves for WC,WHR and WHtR are presented.Average WC increased with age for both genders.Boys had a higher WC than girls until early adolescence and thereafter girls had higher values than boys.WHR decreased both in boys and girls until early adolescence.Thereafter while in boys it plateaued in girls it continued to decrease.Mean WHtR decreased until early adolescence with no gender related differences and thereafter increased more in girls than in boys towards adult age.Prevalence of central obesity largely varied according to the definition used which was 10.9% for WC ≥ 90thpercentile,18.3% for WHtR ≥ 0.5,and 8.6% when fulfilling both criteria.At adjusted logistic regression WC ≥ 90thpercentiles and WHtR ≥ 0.5 were less prevalent in rural than in urban areas(OR = 0.52,95%CI: 0.41-0.67 and 0.66,0.54-0.79 respectively),being more prevalent in children with sedentary lifestyle rather than an active one(1.52,95%CI: 1.17-1.98 and 1.42,95%CI: 1.14-1.75,respectively).CONCLUSION: Yemeni children central obesity indicespercentile curves are presented.Central obesity prevalence varied according to the definition used and was more prevalent in urban sedentary subjects.

Wildfire Occurrence: Integrated Model for Risk Analysis and Operative Suppression Aspects Management

Generally forest fires are related to human activities and need an effective fire prevention and suppression organization, based on a deep knowledge of the territory, fire behaviour and suppression system resources network. To organise monitoring, prevention and fire fighting operations, the knowledge of the risk level for different areas is important. To evaluate the probability that a forest fire occurs and to organise prevention and management of fire fighting activities, both simple and easy-to-use risk and operational difficulty indices were implemented. CNR-IBIMET and DISTAF Dept., on commitment of Tuscany Region, developed a multistep process for the evaluation of the risk, that can be used to assess land planning and to organise seasonal fire fighting resources. This model is called Final Risk Index (FRI);it is the result of the combination of the following two indices, which are initially developed separately. The concerned indices are the Global Risk Index (GRI), and Operational Difficulty Index in Fire Fighting (ODIF). The fire risk index processes different parameters to generate two hazards: static and dynamic, merged to obtain the Global Risk Index (GRI). It is very helpful to estimate the probability of forest fire occurrence, but it does not provide information on forest fire extinction difficulties. The operational difficulty index in fire fighting (ODIF) resumes all the factors affecting fire fighting activity by air and by ground and suggests the extinction efficiency of forest fires in a given area. Thus FRI improves aspects of the fire prevention planning, focused to the needs of a public operative structure. The objective was modelling the links between the main components in ignition and fire fighting actions to produce an easy to use tool to face the emergences, also foreseeing forest fires regime changes in the coming decades.