Pedro A. García

Measurement of the relationship between perceived and computed color differences

Using simulated data sets, we have analyzed some mathematical properties of different statistical measurements that have been employed in previous literature to test the performance of different color-difference formulas. Specifically, the properties of the combined index PF/3 (performance factor obtained as average of three terms), widely employed in current literature, have been considered. A new index named standardized residual sum of squares (STRESS), employed in multidimensional scaling techniques, is recommended. The main difference between PF/3 and STRESS is that the latter is simpler and allows inferences on the statistical significance of two color-difference formulas with respect to a given set of visual data.

Use of arthropods for the evaluation of the olive‐orchard management regimes

Abstract  1 The presence and abundance of arthropods were compared in three olive orchards under organic, integrated and conventional management regimes. In each olive orchard, trees were sampled in the canopy by beating branches and soil arthropods by placing pitfall traps. Contrary to expectations, the highest abundance of arthropods occurred in the integrated management orchard. The most abundant groups were Formicidae and the species Euphyllura olivinae (Homoptera: Psyllidae).

Notes on the application of the standardized residual sum of squares index for the assessment of intra- and inter-observer variability in color-difference experiments

The standardized residual sum of squares index was proposed to examine the significant merit of a given color-difference formula over another with respect to a given set of visual color-difference data [J. Opt. Soc. Am. A 24, 1823-1829, 2007]. This index can also be employed to determine intra- and inter-observer variability, although the full complexity of this variability cannot be described by just one number. Appropriate utilization of the standardized residual sum of squares index for the assessment of observer variability is described with a view to encourage its use in future color-difference research. The main goal of this paper is to demonstrate that setting the F parameters of the standardized residual sum of squares index to 1 results in a loss of essential properties of the index (for example, symmetry), and is therefore strongly discouraged.

Assessing the effects of using compost-sludge mixtures to reduce erosion in road embankments

Recent research shows the benefits derived from applying compost and sludge to road embankments to enhance the cover crop and reduce soil loss due to erosion, particularly in arid environments. Following this line of research, the study described in this paper analyzes and compares the use of sludge and compost for the purposes mentioned. In the first phase of this study, compost or sludge was applied separately to road embankments, and in the second phase both were applied simultaneously. This paper discusses the results obtained in each case. Our study was conducted on a total of 32 plots, located along a road embankment. The 32 plots, each with an area of 20 m(2), were divided into two groups of 16. One group was placed on a 2:1 side slope, and the other was on a 3:2 side slope. Each group received four different compost dosages (0, 40, 60 and 80 t/ha) and four sludge dosages (0, 60, 80 and 100t/ha). Four plant species were selected to be planted in each plot. Our study analyzes the survival rate of the plants, their growth rate and germination, colonization of the plots by other species, cover crop per plot, and soil loss, all in relation to the compost and sludge dosage as well as the side slope type. The results obtained show that when only sludge or compost was applied to the plot, soil loss was reduced by an average of 35%, whereas when a mixture of sludge and compost was applied, soil erosion was reduced by 63% to as much as 90%.

Testing the suitability of insect orders as indicators for olive farming systems

1 A previous study suggested the use of certain insects groups as indicators for detecting organic olive farming in Southern Spain. To validate the use of these groups, insects were collected from olive orchards in Cordoba and Granada, comprising two Andalusian provinces with different surrounding landscapes. 2 Canopies were sampled using the branch‐beating technique during pre‐blooming and post‐blooming periods over 3 years in Granada (1999, 2000 and 2003) and 1 year in Cordoba (2003). 3 Using a nonparametric linear discriminant analysis method, based on the k‐nearest neighbour algorithm, two discriminant functions were constructed. A first discriminant model took into account interannual variability in Granada Province and the second model focused on environmental heterogeneity between the two provinces. Cross‐validation techniques, such as leave‐one‐out and split‐sample, were applied to the associated discriminant functions for each model to check their performance. 4 Even though differences existed with respect to the insect composition of the regions, the second model correctly classified 78.1% of the sampled blocks under the non‐organic and organic farming systems at the same time as taking into account two orders: Coleoptera and Hemiptera [excluding Euphyllura olivina olivina (Psyllidae) and the Heteroptera suborder]. The results suggest that the relative abundance of these groups in the post‐blooming period could constitute a potential bio‐indicator of organic olive farming system.

A nursing educational intervention helped by One Touch UltraSmart™ improves monitoring and glycated haemoglobin levels in type I diabetic children

OBJECTIVES To improve the monitoring and control of glycated haemoglobin in insulin-dependent children. This article describes an educational intervention for this purpose where One Touch UltraSmart Software was used to manage diabetes. The results showed that this intervention helped to reduce the levels of blood glucose and glycated haemoglobin to less than 7%. BACKGROUND Various research studies have been performed on the effective control of glycated haemoglobin values in diabetic children by means of technological devices. However, none of this research has evaluated the impact of an educational intervention in conjunction with the use of monitoring instruments such as One Touch UltraSmart. DESIGN We present an 18-month longitudinal, analytical and observational study of 37 type 1 diabetic patients, 9-16 years of age. For each patient, initial and final values of glycated haemoglobin and the number of blood glucose controls were recorded. METHODOLOGY For the purposes of our study seven educational workshops, attended by diabetic children and their parents, were conducted. In addition, participants were asked to complete a brief questionnaire so that information could be gathered regarding the eating and exercise habits of the patients. RESULTS This educational intervention using One Touch UltraSmart led to a statistically significant average reduction of glycated haemoglobin. CONCLUSIONS Our research showed that the use of One Touch UltraSmart in the context of an educational intervention raised the awareness of the diabetic children and thus helped them to effectively control their disease and to fully understand the necessity of having good dietary and exercise habits. RELEVANCE TO CLINICAL PRACTICE It can be concluded that the educational intervention led to a significant improvement in the dietary habits of these patients and also helped them to exercise regularly, all of which has a positive impact on their health.

Copula-Based Simulation for the Estimation of Optimal Volume for a Detention Basin

Poisson rectangular pulses (PRPs) model describes the probabilistic nature of the average intensity and duration of storms. However, no consideration is given to the peak intensity or the relative position of the peak intensity of the storm. PRP model simplifies the procedure, and makes it attractive to hydrologists; however it can often produce inconsistencies and significant bias in flood estimates, which can lead to the under- or overdesign of engineering structures. This article proposes a model that overcomes the limitations of PRP model by treating the three storm rainfall components (i.e., storm duration, intensity, and the relative position of the peak intensity) as random variables. Their marginal distributions are modeled by using a heavy tailed law, namely, a generalized Pareto as well as Gumbel distributions. The statistical dependence between these three random variables is then modeled using 2-copulas. Finally, the model proposed in this article is applied to the predesign of a detention bas...

Oat and Oat-Vetch as Rainfed Fodder-Cover Crops in Semiarid Environments: Effects of Fertilization and Harvest Time on Forage Yield and Quality

We evaluate the forage yield and quality, species composition, and carrying capacity of oats and oat-vetch as fodder-cover crops, grown in almond orchards, under mineral or organic fertilizer and three harvesting regimes (“grazing,” “hay,” and “grain plus straw”). Also, we show preliminary results of almond yield. Differences in yield due to mineral and organic fertilization were only 9%. The carrying capacity was similar for all treatments. The almond yield was greater when the cover crop was removed early as “grazing.” Therefore, oats and oat-vetch could be used as cover crops in almond orchards if removed early by livestock grazing.

Two-copula based simulation for detention basin design

This article presents a Monte Carlo simulation model based on Clayton copula to generate synthetic sequences of rainfall storms whose likelihood of occurrence is in consonance with historical records. These sequences are used as rainfall input data for the Storm Water Management Model to analyse a 3 km2 watershed in the city of Granada, Spain. The objective of our study is to estimate the optimal volume of a detention basin that would solve the problem created by a downstream combined sewer system (CSS), part of which is undersized and which cannot be enlarged without considerable cost. In this model, the synthetic rainfall sequences provide multiple inputs to the CSS model, which produce a range of model outputs. Risk-based analysis of these outputs helps to quantify the variability of the CSS response. As a result, our model enables decisions based on the comparison of expected outcomes and the costs of different choices. The rainfall storms are represented as a sequence of rectangular pulses, whose occurrences are driven by a Poisson process with a given arrival rate. Both storm durations and average storm intensities are fitted as Pareto distributions and the dependence between these variables is described using Clayton copula.

Copula-EVT-based simulation for optimal rubble-mound breakwater design

The aim of this paper is to present a Monte Carlo based procedure to predict the performance of a rubble-mound breakwater under a randomly generated sequence of sea storms. This approach helps to predict potential damage incurred or possible failures involved in the breakwater during the service time in order to calculate the maintenance cost and consequently to select the optimal design which has the lowest construction and maintenance costs. As a result, the optimal design of the breakwater cross-section can be selected. Using copulas, we investigate the dependence structure existing between the significant wave heights and the significant wave periods, and between the maximum significant wave heights in the storms and the storm durations, since these variables are the main factors affecting the economical breakwater design. The tail of the significant wave heights, the corresponding storm durations and corresponding significant wave periods were fitted by a number of generalised extreme value distributions. We have modelled the joint distribution functions using a dependence measure (Kendalls tau) and its relationship with the class of Archimedean copulas, and then we have chosen the best copula that fits the empirical joint distribution function. To avoid overestimating the virtual effect of the storm, the equivalent triangle storm model is used to represent the generated storms. The damage associated with each individual sea state in the storm is quantified using the Melby formula, and accordingly the cost of the damage or failures is evaluated. The computed total costs for 10 different design significant wave heights and the probability of failure for different design significant wave heights and different service times are presented. In this simulation the failure rate together with the cost are simply double safety controls: one is through the failure rate, and the other is through the cost. If the resulting failure rates are not reasonable, either too low or too high, the cost will indicate this clearly through the rational variation in its value (the larger the failure rate, the lower the initial cost and the higher the maintenance cost, and vice versa).