High Standard Deviation Research Articles

Optical coherence tomography analyses based segmentation and relative intensity evaluation of outer retinal layers in patients affected with X-linked juvenile retinoschisis.

We aim to provide a description of the optical coherence tomography findings in the outer macula hyperreflective bands of our patients with X-linked juvenile retinoschisis. Also to categorize these changes and to quantitatively and qualitatively correlate their reflectivity levels with visual function. We manually segmented the borders, and depicted relative intensity of the inner segment ellipsoid band, and quantified the volume of edema. The average relative intensity of the ellipsoid zone, ISe band, for the control subject was 14.864, our patient's, with the mild disease was, 28.238 and 34.943 in OD and OS, respectively, and for the patient with severe disease was, 44.442 and 40.154 for OD and OS respectively. Thresholding showed a significant difference in edema volume between mild disease (~20%), and severe form (~50%). Relative intensity analyses are indicative of homogeneity variability. High standard deviation value illustrates the high dispersion of data values and is a safe marker of ellipsoid zone homogeneity. Data suggested that both anatomic and functional characteristic of outer macula hyperreflective bands were notably associated with the pathogenesis cascade in the photoreceptor cells. External limiting membrane line disruption is initiated by the volume of macular edema and followed by disorganization of the three lines in a stepwise pattern, first at the ellipsoid zone, followed by the cone outer segment tips zone and finally at the External limiting membrane.

Predator‐scale spatial analysis of intra‐patch prey distribution reveals the energetic drivers of rorqual whale super‐group formation

Abstract Animals are distributed relative to the resources they rely upon, often scaling in abundance relative to available resources. Yet, in heterogeneously distributed environments, describing resource availability at relevant spatial scales remains a challenge in ecology, inhibiting understanding of predator distribution and foraging decisions. We investigated the foraging behaviour of two species of rorqual whales within spatially limited and numerically extraordinary super‐aggregations in two oceans. We additionally described the lognormal distribution of prey data at species‐specific spatial scales that matched the predator's unique lunge‐feeding strategy. Here we show that both humpback whales off South Africa's west coast and blue whales off the US west coast perform more lunges per unit time within these aggregations than when foraging individually, and that the biomass within gulp‐sized parcels was on average higher and more tightly distributed within super‐group‐associated prey patches, facilitating greater energy intake per feeding event as well as increased feeding rates. Prey analysis at predator‐specific spatial scales revealed a stronger association of super‐groups with patches containing relatively high geometric mean biomass and low geometric standard deviations than with arithmetic mean biomass, suggesting that the foraging decisions of rorqual whales may be more influenced by the distribution of high‐biomass portions of a patch than total biomass. The hierarchical distribution of prey in spatially restricted, temporally transient, super‐group‐associated patches demonstrated high biomass and less variable distributions that facilitated what are likely near‐minimum intervals between feeding events. Combining increased biomass with increased foraging rates implied that overall intake rates of whales foraging within super‐groups were approximately double those of whales foraging in other environments. Locating large, high‐quality prey patches via the detection of aggregation hotspots may be an important aspect of rorqual whale foraging, one that may have been suppressed when population sizes were anthropogenically reduced in the 20th century to critical lows. A free Plain Language Summary can be found within the Supporting Information of this article.

Effect of resistance training on muscle properties and function in women with generalized joint hypermobility: a single-blind pragmatic randomized controlled trial

BackgroundGeneralized joint hypermobility is defined as an excessive range of motion in several joints. Having joint hypermobility is not a pathology, but when associated with pain and other symptoms, it might affect health and function. Evidence for physiotherapy management is sparse and resistance training might be a possible intervention. Thus, the effects of 12-week resistance-training on muscle properties and function in women with generalized joint hypermobility were evaluated.MethodsIn this single-blind randomized controlled trial women between 20 and 40 years with generalized joint hypermobility (Beighton score at least 6/9) were included. Participants were randomly allocated to 12-week resistance training twice weekly (experimental) or no lifestyle change (control). Resistance training focused on leg and trunk muscles. Primary outcome was muscle strength; additional outcomes included muscle properties, like muscle mass and density, functional activities, pain and disability. Training adherence and adverse events were recorded.ResultsOf 51 participating women 27 were randomised to training and 24 into the control group. In each group 11 women had joint hypermobility syndrome, fulfilling the Brighton criteria, while 24 (89%) in the training group and 21 (88%) in the control group mentioned any pain. The mean strength of knee extensors varied in the training group from 0.63 (sd 0.16) N/bm before training to 0.64 (sd 0.17) N/bm after training and in the control group from 0.53 (sd 0.14) N/bm to 0.54 (sd 0.15) N/bm. For this and all other outcome measures, no significant differences between the groups due to the intervention were found, with many variables showing high standard deviations. Adherence to the training was good with 63% of participants performing more than 80% of sessions. One adverse event occurred during training, which was not clearly associated to the training. Four participants had to stop the training early.ConclusionsNo improvement in strength or muscle mass by self-guided resistance training was found. Low resistance levels, as well as the choice of outcome measures were possible reasons. A more individualized and better guided training might be important. However, program adherence was good with few side effects or problems triggered by the resistance training.Trial registrationThis trial was prospectively registered in the ISRCTN registry (www.isrctn.com, BMC, Springer Nature) on July 16, 2013 as ISRCTN90224545. The first participant was enrolled at October 25, 2013.

ANALISIS KETIMPANGAN PRODUKTIVITAS DAN DUALISME KETENAGAKERJAAN DI PROVINSI BENGKULU

The purpose of this study is to analyze labor productivity inequality and labor dualism in Bengkulu Province. The method used is descriptive analysis, equipped with class typology and elasticity of employment. We are using employment data from BPS publications. The results show that by dividing business fields into 17 sectors in 2018 and 2019, labor productivity inequality is awfully unequal, which is indicated by a very high standard deviation rate. Meanwhile, labor dualism is led by informal workers by a percentage of over 60%. More workers with primary education are absorbed in the informal sector, whereas educated workers are mostly taken in the formal sector. The highest coefficient of labor absorption elasticity for legal workers occurred in 2016 (3.14) and for informal workers in 2015 (1.73).Keywords: labor dualism, labor productivity

A comparison of reverse projection and PhotoModeler for suspect height analysis

The purpose of this study was to compare the accuracy and precision between the Reverse Projection and PhotoModeler methods for suspect height analysis. Thirty analysts were assigned to measure the heights of three different suspects, one for each method, with the suspects having been recorded standing at three different distances in a scene. For Reverse Projection, the analysts were provided with height scales to place and video-record at the same positions their suspects stood in at the test scene, so that frames could be extracted from the video and overlaid onto frames of the suspects to measure height. For PhotoModeler, analysts calibrated frames of the suspects using 3D point cloud data obtained from a laser scan of the scene, so that measurements could be made in PhotoModeler software. Errors were calculated for the measurements and compared using the Mann-Whitney U-test and Kruskal-Wallis H-test, which indicated significant differences for errors between the two methods (p = 0.0025 and p = 0.008). Reverse Projection yielded a greater range of error and tended to have higher standard deviations than PhotoModeler, but the overall accuracy between the two methods was found to be comparable. The majority of absolute measurement errors for both methods were less than 2 cm.

PERAN KNOWLEDGE SHARING DALAM PENYELESAIAN KONFLIK DI PERUSAHAAN

Sharing knowledge or knowledge sharing has become a separate culture within the company, especially in conflict management. Conflict will always exist as long as two or more humans interact. The difference lies in the size of the conflict. The smaller the conflict, the easier and faster it will be resolved. There are many ways to resolve conflicts, one of which is by implementing or cultivating knowledge sharing within the company. Knowledge sharing makes companies have a breath of togetherness. Every employee who closes himself to one another and is individualistic in the end will eventually create a conflict. This study is to find answers to how the role of knowledge sharing in conflict resolution. This research is a descriptive study using a survey method of 90 respondents. There are 10 questionnaire questions that are given to respondents asking for yes or no answers to each question. The result, of the 10 questions, there were 2 questions where the respondent chose all of the answers yes, while for other questions the respondents were divided, some answered yes and some answered no. The third survey question is the question with the highest standard deviation with a number of 0.461, which means that the data distribution is the most varied.

Association between serum uric acid and triglycerides in Chinese children and adolescents with short stature

BackgroundElevated triglyceride (TG) levels are a biomarker for cardiovascular disease (CVD) risk. The correlation between serum uric acid (SUA) and TG concentrations in adults or obese children is well established. However, studies on SUA and TG in children with short stature are limited.AimTo determine the relationship between SUA and TG levels in short children and adolescents.MethodThis was a cross-sectional evaluation of a cohort of 1095 patients with short stature (720 males and 375 females). The related clinical characteristics, including anthropometric and biochemical parameters, were determined.ResultsSmooth curve fitting, adjusted for potential confounders was performed, which indicated the existence of a non-linear relationship between these measures. Piecewise multivariate linear analysis revealed a significant positive relationship between SUA and TG at SUA concentrations over 7 mg/dL (β = 0.13, 95% CI: 0.05–0.22, P = 0.002) but no significant correlation at lower SUA levels (β = 0.01, 95% CI: 0.01–0.04, P = 0.799). Furthermore, a stratified analysis was performed to appraise changes in this relationship for different sexes and standard deviation levels of body mass index (BMI). The non-linear relationship remained consistent in males and females with BMI standard deviation scores (BMI SDS) ≥ 0, with inflection points of 6.71 mg/dL and 3.93 mg/dL, respectively. Within these two groups, SUA and TG levels showed a positive association when SUA levels were higher than the inflection point (β = 0.21, 95% CI: 0.11–0.31, P < 0.001 for males and β = 0.1, 95% CI: 0.03–0.17, P = 0.005 for females). However, a specific relationship was not observed at lower SUA levels. No significant relationships were found between SUA and TG levels in males and females with BMI SDS < 0.ConclusionThe present study identified the non-linear association of SUA and TG levels with short children and adolescents. This relationship was based on BMI status. This finding suggests that health status should be considered for short stature children with high SUA levels, especially in children with a high BMI standard deviation score.

A comparison of the baseflow recession constant (K) between a Japanese cypress and mixed-broadleaf forest via six estimation methods

The baseflow recession constant (K) is known to be a versatile parameter used in forecasting low flows, flow-frequency analyses, improving regional models, and other various hydrological analyses. This study took place in Inuyama city, Aichi prefecture, central Japan, where K for two catchments of differing vegetation [Japanese cypress (CF), 2.42 ha; mixed-broadleaf (MB), 2.08 ha] were produced via six estimation methods and compared. Water level was recorded by dataloggers (converted to daily discharge) and rainfall, by raingauges. Over 5 years (May 2013–April 2018), 18 baseflow recession events were qualified for analysis from which K were calculated. Overall, K in CF (0.969) was marginally higher than in MB (0.955), which translates to lower water depletion in CF possibly due to lower transpiration. In each catchment, K did not differ significantly between the growth and dormant period. Root mean square error (RMSE) is lower and less variable in CF than in MB. Reproducing baseflow using season-specific K values did not show any clear reduction in RMSE; hence, the complexity is not justified. In general, all K-estimators performed well (low RMSE) and can be used. Out of six K-estimators, two have relatively higher standard deviation (SD) and will underestimate baseflow especially when the K was produced from short (< 6 days) baseflow recession limbs. Others reproduce unbiased baseflow but have relatively higher SD and RMSE. None of the estimators were unusable, but two estimators that have the lowest SD and least bias were recommended.

Relative Performance of Real Estate Exchange-Traded Funds

This paper examines the performance of 34 real estate exchange-traded funds (REETFs) over the period of May 2003 through September 2019. We construct equally-weighted REETF portfolios every month and compare them with the overall U.S. stock market as proxied by the S&P 500 value-weighted ETF (IVV) and the S&P 500 equal-weighted ETF (RSP). Our results show that over the entire time period the REETF portfolios experienced higher monthly returns, but also had a slightly higher standard deviation of returns. We also provide results controlling for risk differentials using the Sharp, Sortino, and Omega ratios. The results show that IVV and RSP had higher risk-adjusted performance using all of the various measures compared with REETFs portfolios. REETFs also had much higher risk and losses during the 2007–2009 financial crisis.

A Comparative Analysis of Mathematical and Linear Regression Models to Predict the Outcomes of COVID-19 Pandemic in Rwanda

The research objective was to investigate the level of COVID-19 outbreak in Rwanda using mathematical and linear models for future prediction of the disease. Both Mathematical model and linear model were used. A sequential mathematical preliminary of COVID-19 was considered to check how it grows within a large number of population. The model diagram was proposed with four compartmental model. The non-linear dynamical system of COVID-19 was derived from the model. The model was checked for positivity and boundedness in system. We found that it’s positively invariant in system. The results also showed that the disease is locally and globally unstable due to the fact that the basic reproduction number is greater than zero i.e., R0 > 0. The basic reproduction number was computed using the next generation Matrix and found that COVID-19 affects a very large population in the system. Method for real data: The study used a sample of 463 COVID-19 daily reports, that is, the available data by 9 April 2021. The data are analyzed using Statistical software (STATA version 13.1). The probability of skewness and kurtosis was P ≤ 0.0001 for New cases, and New deaths. Besides Chi-Square p ≤ 0.0001 for both New cases and New deaths was < 0.05 that means the significance at a 5% level. Results: By comparing the mean and standard deviation, the results show that the number of New cases is higher than that of New deaths, that is 50.00432 with high standard deviation 78.47841, and 0.6781857 with low standard deviation 1.474935; respectively. A spearman rank correlation shows strong correlation between New cases and New deaths. Linear regression analysis model shows that there is a linear relationship of New cases with New deaths. The findings show that the number of deaths will be higher than New cases. Conclusion: The statistics show that COVID-19 is still there within individuals and is moving around. The findings show that in future, the number of new deaths will be higher than that of new cases at a time t. We recommend the government of Rwanda to speed up the Vaccination to the total population to avoid more future deaths due to COVID-19 and to strictly tightening the preventive measures for both Rwandans and incoming travelers. With the above mentioned strategies and the measures, there is a hope that If the whole country is vaccinated, COVID-19 will vanish at time t.

Estimation of Fatigue Strength of Reinforced Complete Upper Denture Using a Newly Designed Testing Machine: A Laboratory Research Project

In the present study, an aero pneumatic fatigue testing machine for complete dentures was designed, fabricated, and tested for the evaluation of the fatigue life of reinforced complete upper denture (CUD). On completion and testing, it was observed that the machine has the potential of generating reliable number of cyclic data. The machine’s performance was evaluated using test specimens of identical CUDs that were machined in conformity with standard procedures. The fatigue machine compressed the lower dental arch over the upper denture-specimen in centric occlusion, in the same way that the two masticatory muscles pull the lower jaw over the upper jaw during chewing. The incorporation of glass fibres into the CUD using a sandwich technique quadruples the lifespan of the denture (P = 0.004). The low standard deviation, along with the low coefficient of variation (CV) of the group of unreinforced dentures shows the repeatability of the results and the reliability of the machine. The high standard deviation and coefficient of variation of reinforced dentures was expected, since a high variation of results is usually recorded in fibre reinforcement cases. This research confirmed the view that the crack during denture fracture initiates in the anterior palatal area and propagates to the posterior.

A study on the relationship between working memory capacity, L2 vocabulary size, and L2 listening proficiency

The purpose of this study is to find out how working memory is related to English vocabulary size and listening comprehension of Korean EFL (English as a Foreign Language) learners. 30 college students, all English education majors, were recruited for the study. In this experiment, the backward digit span task and the operation span task were used to measure the participants’ working memory capacity. The Listening Vocabulary Level Test (LVLT) and the Michigan English Test (MET) were adopted to measure their vocabulary size and listening proficiency, respectively. To analyze the data, both descriptive and inferential statistics, in particular the correlational analysis, were employed. The results show that there is quite a variation in the participants' storage capacity, which was confirmed by the relatively high standard deviations. The correlational analyses reveal that the bigger one’s working memory storage is, the better the person processes incoming input. However, there was no statistically significant correlation between working memory capacity, English vocabulary size, and listening proficiency, which might have been caused by the fact that a small group of relatively homogeneous subjects participated in the study. Follow-up studies with bigger and diverse samples should look at what factors interacts with L2 listening that can affect listening skills in addition to L2 vocabulary knowledge.

An Assembly Quality Inspection System for Bone Conduction Implant Transducers

We designed and implemented a two-axis measurement system to inspect the assembly quality condition of a bone conduction implant (BCI) transducer. The system consists of a laser Doppler vibrometer (LDV), XY manual stage, and two digital scale calipers capable of displaying a position coordinate system. To measure the vibration of the cantilever constituting the transducer vibrational membrane, an XY coordinate system was obtained using FEA software. Based on the derived XY coordinate system, the cantilever vibration displacement of the vibrational membrane was measured for each coordinate using the LDV at 0.5, 0.9, and 2 kHz. To visualize the measured area, we developed a Matlab-based application and then visualized the motion of the cantilever. The alignment and misalignment models of the vibrational membrane and permanent magnet were designed using finite element analysis (FEA) software, and the measured cantilever motions of the vibrational membrane were then compared. Finally, to numerically compare the vibration magnitude of the cantilever, the standard deviation was calculated based on the displacement of each edge of the cantilever. The fabricated BCI transducer had a higher standard deviation (3.5 times at 0.5 kHz, 2.3 times at 0.9 kHz) than the ideally aligned FEA model, but the standard deviation was about eight times lower (at 0.5 and 0.9 kHz) than that of the misaligned case. The results of the numerical comparison indicated that the manufactured BCI transducer was very well assembled.

A Comparative Performance Analysis of Data Resampling Methods on Imbalance Medical Data

Medical datasets are usually imbalanced, where negative cases severely outnumber positive cases. Therefore, it is essential to deal with this data skew problem when training machine learning algorithms. This study uses two representative lung cancer datasets, PLCO and NLST, with imbalance ratios (the proportion of samples in the majority class to those in the minority class) of 24.7 and 25.0, respectively, to predict lung cancer incidence. This research uses the performance of 23 class imbalance methods (resampling and hybrid systems) with three classical classifiers (logistic regression, random forest, and LinearSVC) to identify the best imbalance techniques suitable for medical datasets. Resampling includes ten under-sampling methods (RUS, etc.), seven over-sampling methods (SMOTE, etc.), and two integrated sampling methods (SMOTEENN, SMOTE-Tomek). Hybrid systems include (Balanced Bagging, etc.). The results show that class imbalance learning can improve the classification ability of the model. Compared with other imbalanced techniques, under-sampling techniques have the highest standard deviation (SD), and over-sampling techniques have the lowest SD. Over-sampling is a stable method, and the AUC in the model is generally higher than in other ways. Using ROS, the random forest performs the best predictive ability and is more suitable for the lung cancer datasets used in this study. The code is available at https://mkhushi.github.io/

Development of validated analytical methods and stability indicating studies for pharmaceutical formulation

A simple, accurate rapid and precise has been developed and validated for estimation of Canagliflozin hemihydrate in Pharmaceutical Tablet Formulation by VU-Spectrophotometer and RP-HPLC Method. The successful estimation was carried out of the drug product is developed on the Jasco V-630 and Shimadzu-UV-1700 for VU-Spectrophotometer method and for HPLC successful estimation was carried out of the drug product is developed on the ACE Column C18 (150mm x 4.6mm, 5μm or equivalent) at ambient temperature using Acetonitrile: Orthophosphoric acid (1%) (60: 40 v/v) as mobile phase composition. The flow rate was adjusted to 1.0mL/minute and the absorption maxima were observed on UV detector at 290nm. Retention time for Canagliflozin hemihyd rate 3.0±0.5 min. The linearity was obtained in the concentration range of 80%-120% for Canagliflozin hemihydrate. For the HPLC method injection volume should be 20μL.The method was robust with respect to change in flow rate, temperature and composition of mobile phase. The method was validated statistically and applied successfully for the determination of Canagliflozin hemihydrate by VU-Spectrophotometer and RP-HPLC method. Validation studies revealed that method is specific, rapid, reliable, and reproducible. The high recovery and low relative standard deviation confirm the suitability of the method for the routine determination of Canagliflozin hemihydratein pharmaceutical cream formulation.

Prior Probabilities and the Age Threshold Problem: First and Second Molar Development

Dental development has been used to assess whether an individual may be below or above an age that serves as a legal threshold. This study used development of the first and second mandibular molars from a large sample of individuals (N = 2,676) to examine the age threshold for minimum age of criminal responsibility. A bivariate ordered probit model was applied to dental scores following the Moorrees et al. (1963) system, with the addition of a crypt-absent/present stage. Then a 10-fold cross-validation within each of the sexes showed that the bivariate models produce unbiased estimates of age but are heteroskedastic (with increasing spread of the estimates against actual age). To address the age threshold problem, a normal prior centered on the threshold is assumed, and the product of the prior and the likelihood is integrated up to the age threshold and again starting at the age threshold. The ratio of these two integrals is a Bayes factor, which because the prior is symmetric around the threshold, can also be interpreted as the posterior odds that an individual is over versus under the age threshold. It was necessary to assume an unreasonably high standard deviation of age in the prior to achieve posterior odds that were well above "evens." These results indicate that dental developmental evidence from the first and second molars is of limited use in examining the question of whether an individual is below or over the minimum age of criminal responsibility. As the third molar is more variable in its development than the first two molars, the question of dental evidence regarding the age of majority (generally 18 years) remains problematic.

Dissimilarity weighting for graph-based point cloud segmentation using local surface gradients

Processing of 3D point cloud data is seen as a problem due to the difficulties of processing millions of unstructured points. The point cloud segmentation process is a crucial pre-classification stage such that it reduces the high processing time required to extract meaningful information from raw data and produces some distinctive features for the classification stage. Local surface inclinations of objects are the most effective features of 3D point clouds to provide meaningful information about the objects. Sampling the points into sub-volumes (voxels) is a technique commonly used in the literature to obtain the required neighboring point groups to calculate local surface directions (with normal vectors). The graph-based segmentation approaches are widely used for the surface segmentation using the attributes of the local surface orientations and continuities. In this study, only two geometrical primitives which are normal vectors and barycenters of point groups are used to weight the connections between the adjacent voxels (vertices). The defined 14 possible dissimilarity calculations of three angular values getting from the primitives are experimented and evaluated on five sample datasets that have reference data for segmentation. Finally, the results of the measures are compared in terms of accuracy and F1 score. According to the results, the weight measure W7 (seventh calculation) gives 0.8026 accuracy and 0.7305 F1 score with higher standard deviations, while the original weight measure (W8) of the segmentation method gives 0.7890 accuracy and 0.6774 F1 score with lower standard deviations.

Modelling pool testing for SARS-CoV-2: addressing heterogeneity in populations.

Amplifying the testing capacity and making better use of testing resources is a crucial measure when fighting any pandemic. A pooled testing strategy for SARS-CoV-2 has theoretically been shown to increase the testing capacity of a country, especially when applied in low prevalence settings. Experimental studies have shown that the sensitivity of reverse transcription-polymerase chain reaction is not affected when implemented in small groups. Previous models estimated the optimum group size as a function of the historical prevalence; however, this implies a homogeneous distribution of the disease within the population. This study aimed to explore whether separating individuals by age groups when pooling samples results in any further savings on test kits or affects the optimum group size estimation compared to Dorfman's pooling, based on historical prevalence. For this evaluation, age groups of interest were defined as 0-19 years, 20-59 years and over 60 years old. Generalisation of Dorfman's pooling was performed by adding statistical weight to the age groups based on the number of confirmed cases and tests performed in the segment. The findings showed that when the pooling samples are based on age groups, there is a decrease in the number of tests per subject needed to diagnose one subject. Although this decrease is minuscule, it might account for considerable savings when applied on a large scale. In addition, the savings are considerably higher in settings where there is a high standard deviation among the positivity rate of the age segments of the general population.

Uncertainties Analysis of Collapse Susceptibility Prediction Based on Remote Sensing and GIS: Influences of Different Data-Based Models and Connections between Collapses and Environmental Factors

To study the uncertainties of a collapse susceptibility prediction (CSP) under the coupled conditions of different data-based models and different connection methods between collapses and environmental factors, An’yuan County in China with 108 collapses is used as the study case, and 11 environmental factors are acquired by data analysis of Landsat TM 8 and high-resolution aerial images, using a hydrological and topographical spatial analysis of Digital Elevation Modeling in ArcGIS 10.2 software. Accordingly, 20 coupled conditions are proposed for CSP with five different connection methods (Probability Statistics (PSs), Frequency Ratio (FR), Information Value (IV), Index of Entropy (IOE) and Weight of Evidence (WOE)) and four data-based models (Analytic Hierarchy Process (AHP), Multiple Linear Regression (MLR), C5.0 Decision Tree (C5.0 DT) and Random Forest (RF)). Finally, the CSP uncertainties are assessed using the area under receiver operation curve (AUC), mean value, standard deviation and significance test, respectively. Results show that: (1) the WOE-based models have the highest AUC accuracy, lowest mean values and average rank, and a relatively large standard deviation; the mean values and average rank of all the FR-, IV- and IOE-based models are relatively large with low standard deviations; meanwhile, the AUC accuracies of FR-, IV- and IOE-based models are consistent but higher than those of the PS-based model. Hence, the WOE exhibits a greater spatial correlation performance than the other four methods. (2) Among all the data-based models, the RF model has the highest AUC accuracy, lowest mean value and mean rank, and a relatively large standard deviation. The CSP performance of the RF model is followed by the C5.0 DT, MLR and AHP models, respectively. (3) Under the coupled conditions, the WOE-RF model has the highest AUC accuracy, a relatively low mean value and average rank, and a high standard deviation. The PS-AHP model is opposite to the WOE-RF model. (4) In addition, the coupled models show slightly better CSP performances than those of the single data-based models not considering connect methods. The CSP performance of the other models falls somewhere in between. It is concluded that the WOE-RF is the most appropriate coupled condition for CSP than the other models.

Stone roofing in the Aosta Valley, Italy: Technical properties and durability of traditional Lithotypes

The Aosta Valley Region has promulgated in 1990 a law to partially finance stone roofs to the owners of houses in the historic centers of the valley, provided that the stone material chosen was suitable for this use. This suitability was certified by physical, mechanical and durability tests. More than twenty years ago, roofing slabs were extracted in north-western Alps mainly from schistose rocks. In recent time instead roofing slabs, according to global market, have an international origin. All the traditional stones tested showed excellent technical features according to the local legislation on roof slates. One of these traditional stones is a phyllite whose trade name is “Porfiroide” having the best physical and mechanical properties compared to the other kinds of traditional stones, but with a high standard deviation in the results of flexural strength performed after the freeze and thaw cycles. In the roofing installed 40 years ago, despite their best technical features, the “Porfiroide” roof slabs show a poor state of conservation with widespread detachments, fractures, growth of mosses and lichens, variations in colours. Otherwise, stones with a lower value of flexural strength and higher water absorption instead show good behaviour in the roofing in situ and also in terms of colour change.Evidently the only characterisation of the stone materials is not sufficient but it must be associated to a on-site verification, comparing each slab to be installed with a reference sample, part of the sample submitted to the tests, and to a control on site of the resistance of the stones to degradation.