1,720,993 research outputs found
Homogenization of instrumental time series of air temperature in Central Italy (1930−2015)
Full text linkong-term and high quality instrumental air temperature data are important for reducing the uncertainty of past temperature trends at local and global scales, and for the projection of future expected changes. Currently this type of data is limited in the Mediterranean, which is particularly important since this region is considered a hot spot for climate change. To cover the data gap for Central Italy, a set of territorially dense long-term time series of temperature data covering different climate areas in the Abruzzo region is presented in this work. Due to the possible presence of inhomogeneities (non-climatology irregularities in the data set), a homogenization process was applied to the data. Monthly maximum and minimum temperatures measured at 22 stations were homogenized for the period 1930-2015 using the software HOMER v.2.6. All stations had at least 1 break in the time series, for a total of 89 and 80 inhomogeneities identified in the maximum and minimum temperature series, respectively. The annual amplitude of breaks in the annual series ranged between 0-4.44 degrees C for the maximum temperatures and 0.01-3.75 degrees C for the minimum temperatures. The trend of annual mean temperatures showed increasing temperatures at a regional level starting in the early 20th century, with a greater rate especially after 1980 (0.060 degrees C yr(-1)). The temperature trends, analysed in 3 different intervals (1930-1979, 1950-2015 and 1980-2015) for the 22 time series, demonstrate a slight increase in the rate of warming in the coastal and hilly area during the period 1930-1979 and highlight the importance of local measurements
Bacillus thuringiensis cells selectively captured by phages and identified by surface enhanced raman spectroscopy technique
No full textIn this work, the results on the detection and identification of Bacillus thuringiensis (Bt) cells by using surface-enhanced Raman spectroscopy (SERS) are presented. Bt has been chosen as a harmless surrogate of the pathogen Bacillus anthracis (Ba) responsible for the deadly Anthrax disease, because of their genetic similarities. Drops of 200 μL of Bt suspensions, with concentrations 102 CFU/mL, 104 CFU/mL, 106 CFU/mL, were deposited on a SERS chip and sampled after water evaporation. To minimize the contribution to the SERS data given by naturally occurring interferents present in a real scenario, the SERS chip was functionalized with specific phage receptors BtCS33, that bind Bt (or Ba) cells to the SERS surface and allow to rinse the chip removing unwanted contaminants. Different chemometric approaches were applied to the SERS data to classify spectra from Bt-contaminated and uncontaminated areas of the chip: Principal Component Regression (PCR), Partial Least Squares Regression (PLSR) and Data Driven Soft Independent Modeling of Class Analogy (DD-SIMCA). The first two was tested and trained by using data from both contaminated and un-contaminated chips, the last was trained by using data from un-contaminated chips only and tested with all the available data. All of them were able to correctly classify the SERS spectra with great accuracy, the last being suitable for an automated recognition procedure
Quantification of heavy metals in oils with μL volume by laser induced breakdown spectroscopy and minimazing of the matrix effect
No full textIn this work we describe a method for preparation and analysis of oils by Laser Induced Breakdown Spectroscopy (LIBS), aimed to minimize the necessary sample volume and the matrix effect while maximizing the detection sensitivity and measurement's repeatability. The preparation procedure consists in stabilizing the oil sample and silica wafer substrate at a fixed temperature, here of 40 °C, and in delivering an oil droplet on the wafer rotated by a spin coater. In this way, a uniform oil film is obtained, which thickness is controlled through the rotation speed. So prepared target is then scanned by using the LIBS instrument. From comparative measurements on the pure oil and oil containing 2100 ppm of various elements, we studied different potentials sources of the matrix effect. During the sample preparation, above a certain rotation speed the thickness of the liquid film is the same for the two oils although their kinematic viscosities are very different, meaning that the volume sampled by LIBS is the same. The measured oil transmissivity at the laser wavelength of 1064 nm significantly decreases with concentration of impurities, but this effect could be neglected when dealing with very thin films. The plasma formation threshold measured on the bulk oil samples decreases with the impurity content. In case of pure oil, also for the maximum laser energy here used (165 mJ), the plasma is mainly initiated on the wafer while the presence of impurities increases screening of the substrate by the plasma formed directly on the oil. The matrix effect disappears on a very thin film, here of 0.74 μm, where the C I line intensity in plasma does not vary with the total concentration of impurities between zero and 2100 ppm; simultaneously, the plasma emission becomes stable from one laser pulse to another, contrary to the case of a thick liquid layer. At 0.5 μs from the laser pulse the plasma electron density is much higher in presence of oil than on the bare substrate because of the initial plume confinement. In the optimized experimental conditions the plasma emission from oil was very intense although the sample volume probed by each laser pulse was of 0.3 nL only. By choosing properly the signal acquisition delay and the calibration procedure, the latter is dependent on the excitation energy of the analytical lines, we obtained the detection limits of 3.9 ppm, 0.49 ppm, 0.16 ppm and 0.082 ppm for Zn, Cd, Cu and Cr in oil, respectively
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Understanding future hydrologic challenges: Modelling the impact of climate change on river runoff in central Italy
No full textCompletion of the Central Italy daily precipitation instrumental data series from 1951 to 2019
Full text linkPrecipitation is a critical part of the global hydrological cycle that determines the distribution of water resources. It is also an essential meteorological variable used as input for hydroclimatic models and projections. However, precipitation data frequently lack complete series, especially at daily and sub-daily precipitation stations, which are usually large, bulky, and complex. To address this, gap filling is commonly used to produce complete hydrometeorological data series without missing values. Several gap-filling methods have been developed and improved. This study seeks to fill the gaps of 201 daily precipitation time series in Central Italy by localizing the approach used to generate the Serially Complete dataset for the Planet Earth (SC-Earth). This method combines the outcome of 15 strategies based on four various gap-filling techniques (quantile mapping, spatial interpolation, machine learning, and multi-strategy merging). These strategies employ the daily dataset of the neighbouring stations and the matched ERA5 data to estimate missing values at the target stations. Both raw data and the final serially complete station datasets (SCDs) underwent comprehensive quality control. Many accuracy indicators have been utilized to evaluate the performance of the strategies' estimations and the final SCD, such as Correlation Coefficient (CC), Root mean square error (RMSE), Relative bias (Bias %), and Kling-Gupta efficiency (KGE ''). Multi-strategy merging strategy based on the Modified Kling-Gupta efficiency (MS1) shows the highest performance as an individual precipitation gap-filling strategy. However, the machine learning strategy using random forest (ML3) has the most outstanding share in the final estimates among all other strategies. In the end, the temporal-spatial performance of the final SCD is promising and depends on the pattern of the missing values (MV%). The mean values of KGE '', CC, variability (alpha), and bias term (beta) are 0.9, 0.93, 1.064, and 4.98 x 10-7, respectively.Description of the study area and problem related to missing values and gaps in the data. (Figures 1 and 2). This method combines the outcome of 15 strategies based on four various gap-filling techniques: Four of them rely on quantile mapping with nearby stations (QM). One is based on quantile mapping with concurrent ERA5 estimations (QMR). Four are based on spatial interpolation methods (INT). Four are based on machine learning techniques (ML). Two use multi-strategy merging (MRG). RSME, CC, and the KGE '' are three performance measures used to evaluate the estimated precipitation data from the proposed techniques. (Figure 3). Generating the final SCD and evaluating it using KGE '' and its three elements CC, alpha, and beta (Figure 4).imag
The Correlation between Oral Health and Air Pollution: A Systematic Review
Full text linkThis systematic review assessed to evaluate the potential correlation between oral health and air pollution. To the best of the authors’ knowledge, this is the first systematic review endeavoring to compare air pollution and oral health. A systematic search was performed according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) statement and employed the PICO(S) approach (Patient or Population, Intervention, Control or Comparison, Outcome, and Study types). The search was limited to English-language articles, and publications within a 15-year timeframe were included in the electronic search. A comprehensive search was conducted across PubMed, Scopus, Embase, and Web of Science databases, spanning the years 2008 to 2023, resulting in a total of 4983 scientific articles. A final selection of 11 scientific papers was made based on their study type and the specific air pollutants examined. The selected papers analyzed various air pollutants associated with health-related diseases, including Ozone, Nitrogen Dioxide, Nitrogen Monoxide, Carbon Monoxide, sulfur dioxide, and particulate matter. Three out of eleven of the reviewed studies assert a strong correlation between air pollutants and oral diseases, specifically periodontitis. However, the exact biological mechanisms underlying this correlation do not seem to be fully understood, indicating the need for further comprehensive investigation in this regard. Dentists can contribute to the collective effort by educating their patients about the oral health implications of air pollution, thereby supporting initiatives aimed at promoting environmental and health sustainability
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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