Search results for "construction"
showing 10 items of 2670 documents
Nanotechnology and earth construction: the mechanical properties of adobe brick stabilized by Laponite nanoparticles
2014
The contribution describes the experimental analysis for the improvement of the mechanical properties of samples of earth with the addition of Laponite nanoparticles. Were made two types of samples: the first consisting of soil, sand and water; the second consisting of soil, water, sand and Laponite nanoparticles. The operations performed were: chemical analysis of soil and sand; preparation of samples; Scanning Electron Microscope (SEM) observation of samples for the distribution of the elements, especially the Laponite nanoparticles; testing of compression strength and flexural strength of two types of samples; comparisons of the resulted of the mechanical tests. The improvement of the me…
Evolution of lactase persistence: an example of human niche construction
2011
Niche construction is the process by which organisms construct important components of their local environment in ways that introduce novel selection pressures. Lactase persistence is one of the clearest examples of niche construction in humans. Lactase is the enzyme responsible for the digestion of the milk sugar lactose and its production decreases after the weaning phase in most mammals, including most humans. Some humans, however, continue to produce lactase throughout adulthood, a trait known as lactase persistence. In European populations, a single mutation (−13910*T) explains the distribution of the phenotype, whereas several mutations are associated with it in Africa and the Middle …
Effect of fall direction on the lower hip fracture risk in athletes with different loading histories : A finite element modeling study in multiple si…
2022
Physical loading makes bones stronger through structural adaptation. Finding effective modes of exercise to improve proximal femur strength has the potential to decrease hip fracture risk. Previous proximal femur finite element (FE) modeling studies have indicated that the loading history comprising impact exercises is associated with substantially higher fracture load. However, those results were limited only to one specified fall direction. It remains thus unclear whether exercise-induced higher fracture load depends on the fall direction. To address this, using magnetic resonance images of proximal femora from 91 female athletes (mean age 24.7 years with >8 years competitive career) and …
The guilty, the unlucky, or the unaware? Assessing self-reported behavioral contributors and attributions on pedestrian crashes through structural eq…
2020
Introduction: Recent literature suggests that the causation of pedestrians' crashes and the contribution of safety-related behaviors within them may substantially differ compared to other road users. This study aimed to test the effect of individual factors and safety-related road behaviors on the self-reported walk- ing crashes suffered by pedestrians and, complementarily, to analyze the causes that pedestrians attrib- uted to the crashes they suffered as pedestrians during the previous five years. Method: For this cross- sectional research performed in Spain, data from a nationwide sample of 2,499 pedestrians from the 17 regions of the country were collected. Participants had a mean age o…
Linking empowering leadership to safety participation in nuclear power plants: a structural equation model.
2012
Abstract Introduction Safety participation is of paramount importance in guaranteeing the safe running of nuclear power plants. Method The present study examined the effects of empowering leadership on safety participation. Results Based on a sample of 495 employees from two Spanish nuclear power plants, structural equation modeling showed that empowering leadership has a significant relationship with safety participation, which is mediated by collaborative team learning. In addition, the results revealed that the relationship between empowering leadership and collaborative learning is partially mediated by the promotion of dialogue and open communication. Conclusions The implications of th…
An algorithm for oncologic scalp reconstruction.
2010
Background: Modern reconstructive surgery allows for radical resection and reconstruction of any scalp tumor. However, a significant number of patients are still not treated optimally because of incomplete reconstructive guidelines. Methods: The treatment of scalp tumors was documented in 60 patients over a 10-year period. Data regarding tumor type, size, and localization; reconstructive procedure; oncologic, functional, and aesthetic outcome; and complications were collected and analyzed retrospectively. These data were correlated to recurrence and survival rates. The findings extracted from the data were amalgamated to produce the proposed reconstructive algorithm. Results: Five reconstru…
Virtual Planning and 3D printing modeling for mandibular reconstruction with fibula free flap
2017
Background This study was to evaluate the use of virtual planning and 3D printing modeling in mandibular reconstruction and compare the operation time and surgical outcome of this technique with conventional method. Material and Methods Between 2014 and 2017, 15 patients underwent vascularized fibula flap mandibular reconstruction using virtual planning and 3D printing modeling. Titanium plates were pre-bent using the models and cutting guides were used for osteotomies. 15 patients who underwent mandibular reconstruction using fibula flap without aid of virtual planning and 3D printing models were selected as control group. The operation time was recorded and compared in two groups. Accurac…
A multi-agent safety response model in the construction industry.
2014
BACKGROUND: The construction industry is one of the sectors with the highest accident rates and the most serious accidents. A multi-agent safety response approach allows a useful diagnostic tool in order to understand factors affecting risk and accidents. The special features of the construction sector can influence the relationships among safety responses along the model of safety influences. OBJECTIVE: The purpose of this paper is to test a model explaining risk and work-related accidents in the construction industry as a result of the safety responses of the organization, the supervisors, the co-workers and the worker. METHODS: Sample: 374 construction employees belonging to 64 small Spa…
The associations of indoor environment and psychosocial factors on the subjective evaluation of Indoor Air Quality among lower secondary school stude…
2017
Subjective evaluation of Indoor Air Quality (subjective IAQ) reflects both building-related and psychosocial factors, but their associations have rarely been studied other than on the individual level in occupational settings and their interactions have not been assessed. Therefore, we studied whether schools' observed indoor air problems and psychosocial factors are associated with subjective IAQ and their potential interactions. The analysis was performed with a nationwide sample (N = 195 schools/26946 students) using multilevel modeling. Two datasets were merged: (i) survey data from students, including information on schools' psychosocial environment and subjective IAQ, and (ii) data fr…
Maxillary reconstruction using rectus femoris muscle flap and sagittal mandibular ramus/coronoid process graft pedicled with temporalis muscle
2018
Background Maxillary reconstruction using various pedicled and free-tissue transfer techniques with bone graft or without bone graft has some drawbacks. In this study, we demonstrate maxillary reconstruction using femoris rectus muscle flap and sagittal mandibular ramus/coronoid process graft pedicled with temporalis muscle through the modified lateral lip-submandibular approach. Material and Methods Nine patients suffering from maxillary defects secondary to maxillary cancer ablation, who underwent maxillary reconstruction using rectus femoris muscle flap and sagittal mandibular ramus/coronoid process graft pedicled with temporalis muscle, were enrolled into this study between November 201…