242 research outputs found
Use of Kriging Technique to Study Roundabout Performance
Road intersections are dangerous places because of the many conflicting points between
motorized and nonmotorized vehicles. In the case of defined traffic volume, several research
groups have proved that roundabouts reduced the number of injuries and fatal accident cases.
In recent years, many countries have adopted roundabouts as a standard design solution for
both urban and rural roads. Several recent studies have investigated the performance of
roundabouts, including some with models that calculated the entering flow (Q sub e) as a
function of the circulating flow (Q sub c). Most existing models have been constructed with the
use of linear or exponential statistical regression. The interpolative techniques in classical
statistics are based on the use of canonical forms (linear or polynomial) that completely ignore
the correlation law between collected data. As such, the determined interpolation stems from
the assumption that the data represent a random sample. In the research reported in this
paper, a geostatistical approach was considered: the relationship Q sub e versus Q sub c is
supposed to be a regionalized phenomenon. According to that supposition, collected data do
not represent a random sample of values but are supposed to be related to each other with a
defined law. This recognition allows the realization of interpolation on the basis of the real law of
the phenomenon. This paper discusses the fundamental theories, the applied operating
procedures, and the first results obtained in modeling the Q sub e versus Q sub c relationship
with the application of geostatistics
How Much Do Teachers Earn?
In the continuing debate over how to improve education systems, many people argue that teachers` salaries need to be increased. This paper seeks to establish a reliable method for analyzing the issue using household survey data from Bolivia.
The Educational Gender Gap in Latin America and the Caribbean
This paper analyzes the evolution of gender differences in school attendance and attainment in Latin America and the Caribbean, for both adults who left the educational system and children in school. For individuals 21 years old and above the paper uses a cohort analysis of school attainment. The results indicate that the schooling gap has closed for the cohort born at the end of the 1960s. Since then, the gap has reversed such that within the cohort born in 1980, females have, on average, ÂĽ of a schooling year more than males. During the four decades of birth cohorts of our analysis (1940-1980) the gender gap in attainment has moved in favor of females at a pace of 0. 27 years of schooling per decade. A decomposition exercise suggests that the changes in the schooling gap are mainly explained by the educational attainment of females at the higher levels, rather than improvements in the early years of education. An analysis of attendance and attainment among girls and boys between 6 and 18, for Bolivia, Guatemala, Mexico and Peru (the countries that have not closed the gap in adult schooling attainment) reveals noticeable gender differences, favoring boys, only among older children of the lowest income quintiles and indigenous ethnicity.
Road signs: walking among shapes and colors
Road signs provide information through the combination of three elements: shape, color and pictogram. The current road signs are projected to ensure safety but are designed for adults and not for children. Kids are not small adults and they have a different perception of reality. While planning of home-school pedestrian routes, it is necessary to create road signs that are comprehensible for children aged 6-14. Therefore the elements of road signs were studied individually. The study revealed that both the knowledge of geometric shapes and colors perception are closely related to age and culture and to the teachings which children are submitted to. In fact, some geometric shapes, like the circle, are perfectly recognized from childhood and others less so, such as the rectangle. Moreover children are attracted to basic colors but they are aware of the existence of pastel colors only with teaching. Finally, pictogram must represent a simple symbol that is easily recognized especially from far away. The message generated by the three elements is understandable by children. In fact, children overcome the phase of syncretism after the age of 6, which corresponds to the phase in which children are unable to analyses and syntheses. The result of the research has allowed to design road signs, both vertical and horizontal, that are able to ensure the safety of home-school routes. A road signs study was conducted for Cagliari’s project on road safety. This project involves the use of questionnaires to verify if the road signs are properly designed
Geostatistical Approach for Operating Speed Modelling on Italian Roads
Injuries are one of the main causes of death according to W.H.O. For this reason the attention of road safety researchers especially regards the study of the relationship between driver and road environment. Several research works show that operating speed is an excellent driver behavior parameter. This article describes a different approach to the classical definition of prediction models for operating speed on horizontal curves. In this paper, the fundamental theories, the applied operating procedures and the first results obtained with the application of Geostatistics are discussed. The mathematical models expressing operating speed in function of horizontal curves characteristics found in International scientific literature, have mainly been built on the basis of Classical Statistics. For this reason, it needs to be pointed out that the interpolative techniques found in Classical Statistics are based upon the use of canonical forms (linear or polynomial regressions) that completely ignore the correlation law between collected data. As such, the determined interpolation stems from the assumption that the data represent a random sample. The models described in this article have instead been created with the geostatistical interpolation technique (i.e. Kriging). This technique allows to obtain the "best" estimates possible because it considers the true correlation law between the measured data. The applied methods are then described along with the results obtained in the field of road safety by applying Geostatistics which, for several years, have been used, with positive results, in all scientific and engineering fields dealing with empirical data analysis and processing
La qualificazione degli interessi plurisoggettivi e l’evoluzione dei mezzi di tutela nel sistema amministrativo
Subjective legal positions are legally irrelevant firstly, because they have
superindividual features and they do not refer to a specif subject.
There are many legal scholars who have qualified the interests such as interests of a
purely factual and they have started the discussion of legal consistency of common
interests and arrangements of protection.
Many docrtinal conflicts about protections way of collective interests started due to the
conflicting between collective nature of the interests and personal nature of common
interests.
The problem of relevance has been overcame through the attribution of legal standing to
exponential authorities, bearers of collective interests, then it has gone in search of the
ways of protection both in procedural and in the judicial.
Collective action that finds its most typical expression in the US class action has also
been welcomed in our system and also with regard to public administration, aimed at
overcoming the inefficiencies and reduce bureaucracy delays, with a view 'transparent
administration and higher quality.
In conclusion the discussion can be said dormant, because the common interest have
been overcame instead the assimilation of the candidate positions is increasing, relied
by collective bodies to individual rights
Urinary Metabolites Reveal Hyperinsulinemia and Insulin Resistance in Polycystic Ovarian Syndrome (PCOS)
The identification of insulin resistance and hyperinsulinemia in polycystic ovary syndrome
(PCOS) is not a minor issue. The homeostasis model assessment of insulin resistance index (HOMA)
is the most used index of IR (Insulin Resistance), validated in overweight and obese patients but
not in normal-weight PCOS subjects, who can still present with increased insulin secretion by an
oral glucose tolerance test [OGTT]. The evaluation of insulin secretion and resistance represents a
still unresolved problem. The aim of this study is to identify a possible yet noninvasive method to
properly evaluate the insulin metabolism in young non-diabetic subjects. Girls aged 14–22 years,
afferent to the center of Gynecological Diseases in Childhood and Adolescence of Cagliari (Italy),
were screened for PCOS. A total of 42 subjects comprised the study group. Hormonal assays, OGTT,
transabdominal (TA) or transvaginal (TV) US, and urine collection for 1H-NMR analysis were assayed
in the early follicular phase. A 1H-NMR coupled multivariate statistical analysis was performed. The
OPLS model indicated that the NMR profile of urine had a good fit and prediction ability for the
AUC OGTT with R2 = 0.813. Metabolomics can be a promising tool to the potential identification of
biomarkers of an exaggerated insulin response to OGTT and can encourage substantial progress for a
more accurate and early diagnosis in PCOS
The Echocardiographic Parameters of Systolic Function Are Associated with Specific Metabolomic Fingerprints in Obstructive and Non-Obstructive Hypertrophic Cardiomyopathy
The purpose of this study was to assess whether metabolomics, associated with echocardiography, was able to highlight pathophysiological differences between obstructive (OHCM) or non-obstructive (NOHCM) hypertrophic cardiomyopathy. Thirty-one HCM patients underwent standard and advanced echocardiography; a plasma sample was collected for metabolomic analysis. Results. Patients with OHCM compared with subjects with NOHCM had higher values of 2DLVEF (66.5 ± 3.3% vs. 60.6 ± 1.8%, p < 0.01), S wave (7.6 ± 1.1 vs. 6.3 ± 0.7 cm/s, p < 0.01) and 3D global longitudinal strain (17.2 ± 4.2%, vs. 13.4 ± 1.3%, p < 0.05). A 2-group PLS-Discriminant Analysis was performed to verify whether the two HCM groups differed also based on the metabolic fingerprint. A clear clustering was shown (ANOVA p = 0.014). The most discriminating metabolites resulted as follows: in the NOHCM Group, there were higher levels of threitol, aminomalonic acid, and sucrose, while the OHCM Group presented higher levels of amino acids, in particular those branched chains, of intermediates of glycolysis (lactate) and the Krebs cycle (fumarate, succinate, citrate), of fatty acids (arachidonic acid, palmitoleic acid), of ketone bodies (2-OH-butyrate). Our data point out a different systolic function related to a specific metabolic activity in the two HCM phenotypic forms, with specific metabolites associated with better contractility in OHCM
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