923 research outputs found
Design Product-Service Systems by Using a Hybrid Approach: The Fashion Renting Business Model
As is known, sustainability issues represent one of the main challenges companies have to face. Among all, the fashion industry is considered one of the most impactful, both in terms of resource utilization and pollution. Fashion renting is a recent business model for companies to reduce their environmental footprint, following a circular economy approach. The study aims to develop and discuss the proposed hybrid approach to effectively support fashion companies in designing new business models, taking into account both the customer and the company perspective. On the one hand, agent-based modeling (ABM) allow us to represent customers’ behaviour and interaction. On the other hand, discrete event simulation (DES) paradigm is used to model fashion renting processes. Because customers’ attitude to that service reflects its successful implementation, motivators and barriers have been investigated to be included in the model. The practical implication is defining a model to support fashion companies in designing rental business models before implementing them. From a theoretical point of view, it overcomes the literature gap about the definition of a unique model for fashion renting, including processes, customers and interactions between agents. Follow-up research will include the presentation of simulation results
Vegetation Dynamics of Campos Under Grazing/Fire Regimes in Southern Brazil
Natural grassland vegetation in Southern Brazil, known as campos, has most likely evolved under a disturbance regime that included fire and grazing (Pillar et al., 1997). Nowadays, the composition of the vegetation of campos is grazing- and fire-dependent (Boldrini et al., 1997). Its importance can be evaluated by the fact that it represents 37 % of the state’s area and provides 77 % of the slaughtered cattle at Rio Grande do Sul (Barcellos et al., 2002). The objective of this experiment was to evaluate the vegetation dynamics of campos under grazing/fire regimes in order to explore the resilience of the vegetation under the regimes studied
Reentry vehicles: evaluation of plasma effects on RF propagation
In the frame of communication technology relevant to the re-entry vehicles, the communication black-out occurring in the presence of plasma is one of the main challenging issues. The re-entry plasma is a complex physical system, where the ionization derives from a shock-wave and non-equilibrium phenomena. As discussed elsewhere, the time scales of plasma dynamics (including its evolution along mission trajectory) and radio wave propagation are well separated so that radio wave propagation is solved at an appropriate number of time "snapshots" in which plasma dynamics is held unchanged and considered as known. In this activity, a consistent effort has been devoted to model the electromagnetic problem. For the involved range of oprative frequencies and expected densities, the plasma can be considered as an inhomogeneous dielectric. The associated electromagnetic problem is solved in two steps, via use of the field equivalence principle. The vehicle-plasma system is substituted by equivalent (Love's) currents on its boundary, radiating in free space; the fields at the boundary are obtained by solving the propagation problem from the antenna, installed on the spacecraft, up to the plasma boundary, through the Eikonal approximation. Radiation is then obtained without further approximations. Unlike other well-known numerical methods (e.g. FEM), this technique is not intrinsecally limited by the electrical dimension of the vehicle-plasma system. This enables to analyze high frequency problems. Since the formation of the re-entry plasma critically depends on the re-entry vehicle shape and kinematics, the related model has been directly derived from the output data of the Computational Fluid Dynamics simulations. All the results of the above mentioned activities have been collected in a new software, the AIPT (Antenna In Plasma Tool, integrated into ADF-EMS Antenna Design Framework Electromagnetic Satellite) able to predict the electromagnetic propagation in the presence of plasma
FRAT-up, a Web-based fall-risk assessment tool for elderly people living in the community.
Background: About 30% of people over 65 are subject to at least one unintentional fall a year. Fall prevention protocols and
interventions can decrease the number of falls. To be effective, a prevention strategy requires a prior step to evaluate the fall risk
of the subjects. Despite extensive research, existing assessment tools for fall risk have been insufficient for predicting falls.
Objective: The goal of this study is to present a novel web-based fall-risk assessment tool (FRAT-up) and to evaluate its accuracy
in predicting falls, within a context of community-dwelling persons aged 65 and up.
Methods: FRAT-up is based on the assumption that a subject\u2019s fall risk is given by the contribution of their exposure to each
of the known fall-risk factors. Many scientific studies have investigated the relationship between falls and risk factors. The
majority of these studies adopted statistical approaches, usually providing quantitative information such as odds ratios. FRAT-up
exploits these numerical results to compute how each single factor contributes to the overall fall risk. FRAT-up is based on a
formal ontology that enlists a number of known risk factors, together with quantitative findings in terms of odds ratios. From
such information, an automatic algorithm generates a rule-based probabilistic logic program, that is, a set of rules for each risk
factor. The rule-based program takes the health profile of the subject (in terms of exposure to the risk factors) and computes the
fall risk. A Web-based interface allows users to input health profiles and to visualize the risk assessment for the given subject.
FRAT-up has been evaluated on the InCHIANTI Study dataset, a representative population-based study of older persons living
in the Chianti area (Tuscany, Italy). We compared reported falls with predicted ones and computed performance indicators.
Results: The obtained area under curve of the receiver operating characteristic was 0.642 (95% CI 0.614-0.669), while the Brier
score was 0.174. The Hosmer-Lemeshow test indicated statistical significance of miscalibration.
Conclusions: FRAT-up is a web-based tool for evaluating the fall risk of people aged 65 or up living in the community. Validation
results of fall risks computed by FRAT-up show that its performance is comparable to externally validated state-of-the-art tools.
A prototype is freely available through a web-based interface.
Trial Registration: ClinicalTrials.gov NCT01331512 (The InChianti Follow-Up Study);
http://clinicaltrials.gov/show/NCT01331512 (Archived by WebCite at http://www.webcitation.org/6UDrrRuaR)
Relationship between bone cross-sectional area and indices of peripheral artery disease
Most studies on the relationship between bone mineral density and atherosclerosis have used dual-energy X-ray absorptiometry, but this method is relatively insensitive to bone geometry. The aim of this study was to investigate the relationship between bone area and indices of carotid and peripheral atherosclerosis. We studied 841 persons aged 65 years or older (women = 444, mean age 73.8 years; men = 397, mean age = 75.3 years) enrolled in the InCHIANTI study and free from active malignancies, chronic use of bisphosphonates or steroids, and estrogen replacement therapy. The tibial cortical and total cross-sectional area (CSA) were measured by peripheral quantitative computed tomography and their ratio was calculated (cortical/total cross-sectional area ratio, cCSA/tCSA); carotid plaques were screened by echography, and peripheral artery disease (PAD) was defined as an ankle/brachial index <0.9 or presence of intermittent claudication. No association between cCSA/tCSA and atherosclerosis was observed in men. In women, lower cCSA/tCSA was associated with both carotid plaques [odds ratio (OR) for lowest vs. best quartile = 2.09, 95 % confidence interval (CI) 1.2-3.68] and PAD (OR = 3.43, 95 % CI 1.58-8.12). After correction for potential confounders (age since menopause, body mass index, Parathyroid hormone, vitamin D, leptin, DHEA-S, testosterone, physical activity, chronic obstructive pulmonary disease, and reduced renal function), the association was not confirmed. According to partial logistic regression, the carotid plaque-cCSA/tCSA association, but not the PAD-cCSA/tCSA association, was mostly dependent on years since menopause. In women the association between osteoporosis and carotid plaques likely reflects hormonal deprivation, whereas that between osteoporosis and PAD seems multifactorial in origin. © 2013 Springer Science+Business Media New York
Reentry vehicles: evaluation of plasma effects on RF propagation
In the frame of communication technology relevant to the re-entry vehicles, the communication black-out occurring in the presence of plasma is one of the main challenging issues. The re-entry plasma is a complex physical system, where the ionization derives from a shock-wave and non-equilibrium phenomena. As discussed elsewhere, the time scales of plasma dynamics (including its evolution along mission trajectory) and radio wave propagation are well separated so that radio wave propagation is solved at an appropriate number of time "snapshots" in which plasma dynamics is held unchanged and considered as known. In this activity, a consistent effort has been devoted to model the electromagnetic problem. For the involved range of oprative frequencies and expected densities, the plasma can be considered as an inhomogeneous dielectric. The associated electromagnetic problem is solved in two steps, via use of the field equivalence principle. The vehicle-plasma system is substituted by equivalent (Love's) currents on its boundary, radiating in free space; the fields at the boundary are obtained by solving the propagation problem from the antenna, installed on the spacecraft, up to the plasma boundary, through the Eikonal approximation. Radiation is then obtained without further approximations. Unlike other well-known numerical methods (e.g. FEM), this technique is not intrinsecally limited by the electrical dimension of the vehicle-plasma system. This enables to analyze high frequency problems. Since the formation of the re-entry plasma critically depends on the re-entry vehicle shape and kinematics, the related model has been directly derived from the output data of the Computational Fluid Dynamics simulations. All the results of the above mentioned activities have been collected in a new software, the AIPT (Antenna In Plasma Tool, integrated into ADF-EMS Antenna Design Framework Electromagnetic Satellite) able to predict the electromagnetic propagation in the presence of plasm
Morphogenesis and Defoliation Frequency of Italian Ryegrass (\u3ci\u3eLolium multiflorum\u3c/i\u3e) and \u3ci\u3ePaspalum urvillei\u3c/i\u3e in Lowland under Three Levels of P and K
This trial was conducted to evaluate growth dynamics and defoliation frequency of Italian ryegrass (Lolium multiflorum) and Paspalum urvillei in a lowland area under three levels of P and K. Using randomization tests we observed that, in a general way, fertilizer treatments were not the determinant factors of leaf appearance and elongation rates for both species. Only the leaf appearance rate of Paspalum urvillei at 100 % of recommendation level and the elongation rate for Italian ryegrass, in the same treatment, was different. Probably other factors, like drainage, are contributing to these results. I. ryegrass phyllochron ranged from 57.3 to 72.6 degree-days. Paspalum urvillei presented higher grazing frequency in almost all evaluated periods, revealing a high preference by the grazing animals
Epidemiology of Hip and Knee Pain in a Representative Cohort of Italian Persons Aged 65 and Older
The GOODSTEP project: General Object-Oriented Database for Software Engineering Processes
The goal of the GOODSTEP project is to enhance and improve the functionality of a fully object-oriented database management system to yield a platform suited for applications such as software development environments (SDEs). The baseline of the project is the O2 database management system (DBMS). The O2 DBMS already includes many of the features regulated by SDEs. The project has identified enhancements to O2 in order to make it a real software engineering DBMS. These enhancements are essentially upgrades of the existing O2 functionality, and hence require relatively easy extensions to the O2 system. They have been developed in the early stages of the project and are now exploited and validated by a number of software engineering tools built on top of the enhanced O2 DBMS. To ease tool construction, the GOODSTEP platform encompasses tool generation capabilities which allow for generation of integrated graphical and textual tools from high-level specifications. In addition, the GOODSTEP platform provides a software process toolset which enables modeling, analysis and enaction of software processes and is also built on top of the extended O2 database. The GOODSTEP platform is to be validated using two CASE studies carried out to develop an airline application and a business application
Epidemiology of Back Pain in a Representative Cohort of Italian Persons 65 Years of Age and Older: the InCHIANTI Study
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