Testing machine learning algorithms for the prediction of depositional fluxes of the radionuclides 7Be, 210Pb and 40K

The monthly depositional fluxes of ⁷Be, ²¹⁰Pb and ⁴⁰K were measured at Malaga, (Southern Spain) from 2005 to 2018. In this work, the depositional fluxes of these radionuclides are investigated and their relations with several atmospheric variables have been studied by applying two popular machine learning methods: Random Forest and Neural Network algorithms. We extensively test different configurations of these algorithms and demonstrate their predictive ability for reproducing depositional fluxes. The models derived with Neural Networks achieve slightly better results, in average, although similar, having into account the uncertainties. The mean Pearson-R coefficients, evaluated with a k-fold cross-validation method, are around 0.85 for the three radionuclides using Neural Network models, while they go down to 0.83, 0.79 and 0.8 for ⁷Be, ²¹⁰Pb and ⁴⁰K, respectively, for the Random Forest models. Additionally, applying the Recursive Feature Elimination technique we determine the variables more correlated with the depositional fluxes of these radionuclides, which elucidates the main dependences of their temporal variability.

7Be, 210Pb and 40K depositions over 11 years in Málaga

The monthly bulk depositional fluxes of three natural radionuclides (⁷Be, ²¹⁰Pb and ⁴⁰K) were measured at a Mediterranean coastal station (Málaga) over an 11-year period from 2005 to 2015. The mean annual depositional fluxes of ⁷Be, ²¹⁰Pb and ⁴⁰K were 1215, 144 and 67 Bq m^-2 year^-1 respectively, showing a clear seasonal trend with minimum values recorded during summer and maximum values in winter. The rainfall regime with dry summers allows estimating the dry deposition. Assuming constant dry deposition through each year, ⁷Be, ²¹⁰Pb and ⁴⁰K would account for 12.5, 26.5 and 33% of the bulk fallout respectively which indicates that deposition for ²¹⁰Pb and ⁴⁰K are significantly higher than ⁷Be. The precipitation-normalized enrichment factor alpha used to explain seasonal variations in the depositional fluxes of radionuclides with respect the rainfall, indicates higher depositional fluxes during spring and summer than expected from the amount of rainfall. Despite their different origin, ²¹⁰Pb and ⁷Be monthly depositional fluxes have strong correlation. The atmospheric deposition fluxes of ⁷Be, ²¹⁰Pb and ⁴⁰K were controlled mainly by the amount of rainfall (r = 0.89, 0.91 and 0.66 respectively). Moreover, principal component analysis was applied to the datasets and deposition of radionuclides and rainfall in the same component highlighting the importance of the washout mechanism. The mean depositional velocity of aerosols evaluated using ⁷Be and ²¹⁰Pb are similar and are compared to other published values.

Study of ⁷Be and ²¹⁰Pb as radiotracers of African intrusions in Malaga (Spain)

The relationship between the particulate matter in the atmosphere of Malaga and the origin of air masses with special attention to African intrusions was analyzed. The concentrations of PM10 and the activities of some radionuclides ((7)Be and (210)Pb) as tracers of these intrusions are discussed. The origin of these radiotracers is completely different. (210)Pb is a good tracer of air masses traveling close to the ground and come from inland areas. On the other hand, the production of (7)Be is very low in the vicinity of the Earth's surface, and increases with altitude, making it a great tracer of stratospheric air masses in the troposphere. Studies of radionuclide activities in aerosol particles provide a means for evaluating the integrated effects of transport and meteorology on the atmospheric loadings of substances with different sources. Measurements of aerosol mass concentration and specific activities of (7)Be and (210)Pb in aerosols at Malaga (36° 43' 40″ N; 4° 28' 8″ W) for the period 2009-2011 were used to obtain the relationships between radionuclide activities and airflow patterns by comparing the data grouped by air mass trajectory. The average concentration values of (7)Be and (210)Pb over the 3-year period have been found to be 5.05 and 0.55 mBq m(-3), respectively, with mean aerosol mass concentration of 53.6 μg m(-3). Taking into account the outbreaks of the daily values limits of PM10 in the study period (2009-2011), the origin of air masses is studied to explain three different situations of both radionuclides (7)Be and (210)Pb: 1) high concentrations of (7)Be and low concentrations of (210)Pb; 2) high concentrations of (210)Pb and low concentrations of (7)Be and 3) high concentrations of (7)Be and (210)Pb.

Behavior of ambient concentrations of natural radionuclides (7)Be, (210)Pb, (40)K in the Mediterranean coastal city of Málaga (Spain)

During a 4-year period (January 2009-December 2012), the (7)Be, (210)Pb, and (40)K activity concentrations in airborne particulate matter were weekly determined at the Málaga (Spain) located in the southern Iberian Peninsula. Totally 209 polypropylene filters were analyzed in the mentioned period. In 100% of the filters, (7)Be and (40)K activity concentrations were detected while (210)Pb activity concentration was detected in 96% of the filters. The results from individual measurements of (7)Be, (210)Pb, and (40)K concentrations were analyzed to derive the statistical estimates characterizing the distributions. Principal components analysis (PCA) was applied to the datasets and the results of the study reveal that aerosol behavior is represented by two principal components which explain 73.2% of total variance. Components PC1 and PC2 respectively explain 46.0 and 27.2% of total variance. PC1 was related positively to dust content, (7)Be and (40)K concentrations and negatively to sunspot numbers. In contrast, PC2 was related positively to temperature and (210)Pb activity and negatively to precipitation and relative humidity. The (7)Be levels showed a significant correlation with sunspot numbers due to the cosmogenic origin. (40)K activities showed a good correlation with dust deposition in filters mainly because it was transported to the air as resuspended particle from the soil. An inverse relationship was observed between the (210)Pb concentrations and monthly rainfall, indicating washout of atmospheric aerosols carrying these radionuclides and a pronounced positive correlation with the average monthly temperature of air.

Effects of collector types in sampling of atmospheric depositional fluxes

The bulk gross alpha, gross beta and (7)Be depositional fluxes were measured in Málaga (36.7 degrees N, 4.5 degrees W), a coastal Mediterranean station in the south of Spain for one whole year. In order to quantify the local variation of deposition rates, we have analysed the monthly results from two deposition collectors: a "pot "collector with a continuous water-covered surface and a "funnel" collector. In general, the alpha and beta depositional fluxes from the funnel collector were approximately two times lower than the pot collector. Whereas for the cosmogenic (7)Be, the depositional flux of (7)Be from funnel collector was also approximately two times lower than the pot collector. A good correlation of the depositional flux of (7)Be has been obtained from both collectors.

Effects of inspiratory muscle training on exercise capacity and spontaneous physical activity in elderly subjects: a randomized controlled pilot trial

Inspiratory muscle training (IMT) has been shown to improve exercise capacity in diseased populations. We chose to examine the effects of eight weeks of IMT on exercise capacity and spontaneous physical activity in elderly individuals. Eighteen moderately active elderly subjects (68.1 +/- 6.8 years [mean +/- SD]; range 58 - 78 years) were randomly assigned to either an experimental group (n = 9) or a control group (n = 9) in a double-blind manner. All subjects underwent inspiratory muscle testing, treadmill exercise testing and a four-day measurement period of spontaneous physical activity (using accelerometry) both pre- and post-intervention. The experimental group underwent eight weeks of incremental IMT using a pressure threshold device, while the control group underwent sham training using identical devices. After IMT training, inspiratory muscle strength (mean + 21.5 cm H (2)O; 95 % CI: 9.3, 33.7; p = 0.002), V.O (2peak) (+ 2.8 ml x min (-1) x kg (-1); 95 % CI: 0.5, 5.2; p = 0.022), time to exhaustion during a fixed workload treadmill test (+ 7.1 min; 95 % CI: 1.8, 2.4; p = 0.013) and time engaged in moderate-to-vigorous physical activity (+ 59 min; 95 % CI: 15, 78; p = 0.008) improved. Except for a decline in moderate-to-vigorous physical activity, no significant changes were seen in the control group. Therefore, IMT may be a useful technique for positively influencing exercise capacity and physical activity in elderly individuals.

Exhalation of (222)Rn from phosphogypsum piles located at the Southwest of Spain

Phosphogypsum (PG) is a waste product of the phosphoric acid production process and contains, generally, high activity concentrations of uranium series radionuclides. It is stored in piles formed over the last 40 years close to the town of Huelva (Southwest of Spain). The very broad expanse of the PG piles (about 1200 ha) produces a local, but unambiguous, radioactive impact to their surroundings. In 1992, the regional government of Andalusia restored an area of 400 ha by covering it with a 25-cm thick layer of natural soil and, currently, there is an additional zone of 400 ha in course of restoration (unrestored) and the same area of active PG stacks. Due to the high activity concentration of (226)Ra in active PG stacks (average 647 Bq kg(-1)), a significant exhalation of (222)Rn could be produced from the surface of the piles. Measurements have been made of (222)Rn exhalation from active PG stacks and from restored and unrestored zones. The (222)Rn exhalation from unrestored zones is half of that of the active PG stacks. Following restoration, the (222)Rn exhalation is approximately eight times lower than the active PG stacks. The activity concentrations of natural radionuclides ((226)Ra, (40)K, (232)Th) in the mentioned zones have been determined. This study was also conducted to determine the effect of (226)Ra activity concentration on the (222)Rn exhalation, and a good correlation was obtained between the (222)Rn exhalation and (226)Ra activity, porosity and density of soil.

Combined aerobic and resistance training in breast cancer survivors: A randomized, controlled pilot trial

The purpose of this pilot study was to examine the effects of a combined cardiorespiratory and resistance exercise training program of short duration on the cardiorespiratory fitness, strength endurance, task specific functional muscle capacity, body composition and quality of life (QOL) in women breast cancer survivors. Sixteen subjects were randomly assigned to either a training (n = 8; age: 50 +/- 5 yrs) or control non-exercising group (n = 8; age: 51 +/- 10 yrs). The training group followed an 8-week exercise program consisting of 3 weekly sessions of 90-min duration, supervised by an experienced investigator and divided into resistance exercises and aerobic training. Before and after the intervention period, all of the subjects performed a cardiorespiratory test to measure peak oxygen uptake (VO2peak), a dynamic strength endurance test (maximum number of repetitions for chest and leg press exercise at 30 - 35 % and 100 - 110 % of body mass, respectively) and a sit-stand test. Quality of life was assessed using the European Organization for Research and Treatment of Cancer QLQ-C30 (EORTC-C30) questionnaire. In response to training, QOL, VO2peak (mean 3.9 ml/kg/min; 95 % CI, 0.93, 6.90) performance in leg press (17.9 kg; 95 % CI, 12.8, 22.4) and sit-stand test (- 0.67 s; 95 % CI, - 0.52, - 1.2) improved (p < or = 0.05). We observed no significant changes in the control group. Combined cardiorespiratory and resistance training, even of very brief duration, improves the QOL and the overall physical fitness of women breast cancer survivors.

Does the C34T Mutation in AMPD1 Alter Exercise Capacity in the Elderly?

Ageing does affect functional capacity through several changes at the peripheral muscle level that impair the muscles capacity to produce energy and generate force. The skeletal muscle-specific isoform of AMP deaminase (AMPD) plays an important regulatory role in muscle metabolism and in determining energy charge. Since nearly 20 % of the general Caucasian population is heterozygous (CT) for the most common C34T mutation of the gene (AMPD1) encoding for this enzyme, it would be worthwhile to study if such a condition further increases the effects of ageing. Twenty-one women (61 - 80 yrs) served as subjects, and depending on the results of previous genotyping, were assigned to a group with the C34T mutation (heterozygous; n=4; mean+/-SEM age: 71+/-1 yrs) or with no mutation (n=17; 68+/-1 yrs). Several indices of maximal (peak oxygen uptake [V.O (2 peak)], peak power output) and submaximal endurance performance (ventilatory threshold, mechanical efficiency) and functional tests (one-mile walk test and a specific test of lower-body functional performance [sit-stand test]) were compared between the two groups. No significant differences were found in exercise capacity between both groups, e. g. V.O (2 peak) of 19.1+/-1.0 vs. 20.1+/-1.9 ml . kg (-1) . min (-1), V.O (2) at the VT of 11.9+/-0.6 vs. 12.9+/-1.0 ml . kg (-1) . min (-1), or time to complete the one-mile walk test (951+/-18 s vs. 962+/-61 s) and sit-stand test (9.9+/-0.2 vs. 9.2+/-0.2) (no mutation vs. C34T mutation, respectively). Although more research is necessary, it seems that the C34T mutation of the AMPD1, at least in heterozygous individuals, does not affect functional capacity in the elderly.

Does complete deficiency of muscle alpha actinin 3 alter functional capacity in elderly women? A preliminary report

The sarcomeric protein alpha actinin 3 is localised to the Z line of fast fibres, which are responsible for generating forceful muscle contractions at high velocity. However, a substantial proportion of healthy humans are totally deficient in this protein as they are homozygous for a premature stop codon polymorphism (R577X) in the ACTN3 gene. The purpose of this preliminary study was to assess if the presence or absence of alpha actinin 3 influences the deleterious effects of ageing on muscle output and functional capacity.

Stochastic model to forecast ground-level ozone concentration at urban and rural areas

Stochastic models that estimate the ground-level ozone concentrations in air at an urban and rural sampling points in South-eastern Spain have been developed. Studies of temporal series of data, spectral analyses of temporal series and ARIMA models have been used. The ARIMA model (1,0,0) x (1,0,1)24 satisfactorily predicts hourly ozone concentrations in the urban area. The ARIMA (2,1,1) x (0,1,1)24 has been developed for the rural area. In both sampling points, predictions of hourly ozone concentrations agree reasonably well with measured values. However, the prediction of hourly ozone concentrations in the rural point appears to be better than that of the urban point. The performance of ARIMA models suggests that this kind of modelling can be suitable for ozone concentrations forecasting.

Analyses of ozone in urban and rural sites in Málaga (Spain)

Ozone concentrations were measured at two (urban and a rural) sites near the city of Málaga (Spain). The aim of this study was to determine the daily, monthly and seasonal variation patterns of ozone concentrations at both sites and to study the possible regional influences. The daily variations mostly have the usual features with the afternoon maximum and the night minimum being more pronounced in the urban area. The average monthly concentrations throughout the year start to increase in March reaching their maximum values in July for the urban site. However, in the rural area, the monthly variations are smaller reaching their maximum value in June. The hourly evolution of the ozone concentrations in both sampling sites is well defined in spring and summer and not so well defined in autumn and winter. Taking into account the four seasons, the rural concentrations are higher than the urban ones. Summer is the season when there are similar concentrations at both sampling sites. Average hourly summer afternoon ozone for the hours 12:00-20:00 LST exceeded the 110 microg m(-3) European Union guidelines for human health for 8 h ozone exposure at the urban and rural sites.

Assessment of ozone variations and meteorological effects in an urban area in the Mediterranean Coast

Ozone concentrations are valuable indicators of possible health and environmental impacts. However, they are also used to monitor changes and trends in the sources of both ozone and its precursors. For this purpose, the influence of meteorological variables is a confusing factor. This study presents an analysis of a year of ozone concentrations measured in a coastal Spanish city. Firstly, the aim of this study was to perceive the daily, monthly and seasonal variation patterns of ozone concentrations. Diurnal cycles are presented by season and the fit of the data to a normal distribution is tested. In order to assess ozone behaviour under temperate weather conditions, local meteorological variables (wind direction and speed, temperature, relative humidity, pressure and rainfall) were monitored together with ozone concentrations. The main relationships we could observe in these analyses were then used to obtain a regression equation linking diurnal ozone concentrations in summer with meteorological parameters.

Gross-alpha and gross-beta activities in airborne particulate samples. Analysis and prediction models

Measurements of gross-alpha and gross-beta activities were made every week during the years 1992-1997 for airborne particulate samples collected using air filters at a clear site. The data are sufficiently numerous to allow the examination of variations in time and by these measurements to establish several features that should be important in understanding any trends of atmospheric radioactivity. Two models were used to predict the gross-alpha and gross-beta activities. A good agreement between the results of these models and the measurements was highlighted.