A matching procedure to improve k-NN estimation of forest attribute maps

The integration of forest inventory and mapping has emerged as a major issue for assessing forest attributes and multiple environmental functions. Associations between remotely sensed data and the biophysical attributes of forest vegetation (standing wood volume, biomass increment, etc.) can be exploited to estimate the attribute values for sampled and non-sampled pixels, thus producing maps for the entire region of interest. Among the available procedures, the k-nearest neighbours (k-NN) technique is becoming popular, even for practical applications. However, the k-NN estimates at the pixel level tend to average towards the population mean and to have suppressed variance, since large values are usually underestimated and small values overestimated. This tendency may be detrimental for k-NN applications in forest resource management planning and scenario analysis where the representation of the spatial variability of each attribute of interest across the surveyed territory is fundamental. The present paper proposes a procedure to tackle such an issue by modifying k-NN estimates via a post-processing procedure of distribution matching. The empirical distribution function of the population values is estimated from the sample of ground data by using the 0-inflated beta distribution as the assisting model and the k-NN estimates are subsequently modified in such a way as to match the estimated distribution. The statistical properties of the distribution matching estimators for totals and averages are theoretically derived, while the performance of the distribution matching estimator at the pixel level are empirically evaluated by a simulation study.L'articolo è disponibile sul sito dell'editore www.Journals.elsevier.co

Assessing the attributes of scattered trees outside the forest by a multi-phase sampling strategy

A sampling strategy to be used with multi - phase forest inventories is proposed for assessing scattered trees outside the forest on large territories. The fi rst phase is carried out by means of a systematic search over the area to be inventoried. The area is partitioned into regular polygons of the same size and points are randomly located, one per polygon. Subsequently, in the second phase, the land cover class of the fi rst-phase points is determined by very high - resolution remotely sensed imagery and a sample of points are selected from each land cover stratum. Then, the number of trees outside the forest lying within plots at the sampled points is recorded on the imagery. Finally, in the third phase, a subsample is selected from the second-phase samples of each stratum and the biophysical attributes of trees within plots are measured in the fi eld. Approximately unbiased estimators of abundance and of totals and averages of biophysical attributes are achieved in the second and third phase , respectively, together with the estimators of the corresponding variances. A simulation study is performed in order to assess the accuracy of the strategy under random and aggregated distributions of trees. The sampling errors achieved in the second phase using sampling fractions of ~ 0.3 per cent of trees vary from 6 to 13 per cent , whereas the errors achieved in the third phase using sampling fractions of ~ 0.15 per cent vary from 15 to 31 per cent . The results obtained from three case studies carried out in Italy confi rm the accuracy levels achieved in the simulation.L'articolo è disponibile sul sito dell'editore http://forestry.oxfordjournals.org

Influence of school schedules on physical activity patterns in primary school children: a case study in Italy

Background: Considering the relevant amount of time spent by children at school, it is essential to ensure that suitable levels of physical activity (PA) are guaranteed. This study aimed to assess possible changes induced in the amount and type of PA performed following the two schedules in Italian primary schools, namely regular and full time (30-40 h/week respectively). Methods: A sample of 169 children wore a tri-axial accelerometer 24h/day for 7 consecutive days. Raw data were processed to calculate the number of steps, amount and intensity of the PA performed in morning, afternoon and evening time slots. Results: During weekday afternoon times (1:30 – 4:30 PM), children attending the full-time schedule spent significantly less time in sedentary behavior with respect to those who attend the regular time (54.7% vs. 60.0%, p<0.001) and more time in moderate-to-vigorous activity (18.0% vs. 15.0%, p=0.004). No differences between morning and evening times were found. Conclusions: The structure of the full time schedule, which includes a second recess, promotes higher and more intense levels of PA during the afternoon. Such information represent a useful input in planning differential PA activities for children attending the regular time to achieve similar PA levels for the whole school population

Lung ultrasound evaluation in people with cystic fibrosis: A new approach in the pulmonology outpatient clinic

Background: Cystic fibrosis (CF) is a genetic disease that causes progressive lung disease with major impact on the quality of life. Lung ultrasound (LUS) allows to assess the lung involvement through the artefacts analysis and is increasingly used in children but is not yet used to monitor people with CF(pwCF). The main aim of this study was to describe the LUS pattern of pwCF during their routinary check-up visit. The secondary objective was to correlate the LUS findings with pulmonary function indices. Methods: We performed a cross-sectional observational study, enrolling adolescents and young adults with CF. Each patient underwent clinical assessment, measurement of SpO2, assessment of lung function by spirometry and LUS. Results: Twenty-nine subjects with CF were included. The most frequent alterations were consolidations (72.4%) located in the left apical anterior and right apical posterior regions followed by interstitial syndrome (65.5%). The 41.4% of cases presented the lingula involvement, characterized by a consolidation with static air bronchogram, and 55.2% showed pleural irregularity mainly in the posterior apical regions. A significant correlation was found between the LUS total score and spirometric indices: FEV1 (p = .003), FVC (p = .002), Tiffenau Index <80% (p = .014), and FEF 25-75 (p = .004). Conclusions: Our study describes LUS findings in pwCF. It also showed a correlation between LUS score and the patients' lung function measured by spirometric indices. We conclude that LUS may be useful in routine monitoring of pwCF in combination with clinical and spirometric assessment

A toddler with an unusually severe polyarticular arthritis and a lung involvement: a case report

COPA syndrome is a rare hereditary inflammatory disease caused by mutations in the gene encoding the coatomer protein subunit alpha, causing excessive production of type I interferon. This case is a reminder for the general paediatrician, highlighting the relevance of the association between arthritis and lung involvement in toddlers