157 research outputs found
El Centro Médico Psicopedagogico Salesiano
Esta obra es la reedición de la tesis doctoral de Emilio Gambirasio sdb (1922-1991) la cual propone los principios conceptuales, metodológicos y operativos de un centro médico psicopedagógico salesiano. No se trata de una investigación abstracta ya que recoge la experiencia y la reflexión del autor sobre su trabajo concreto y creativo al frente del Centro Psicológico Salesiano desde sus años fundacionales. Ello le ha permitido identificar las motivaciones, los aspectos organizacionales y las dimensiones de las actividades diagnósticas y terapéuticas de un Centro que ha dejado profunda huella en los departamentos de orientación y bienestar estudiantil de las unidades educativas, principalmente de Quito.
El libro ha sido concebido por el Dr. Patricio Bermúdez, profesor de la Carrera de Psicología y discípulo del autor, para garantizar la reflexión y memoria de las fuentes que inspiran el funcionamiento actual del Centro. A la vez, se constituye en un homenaje al fundador de una iniciativa vigente que ha persistido en el tiempo
Ecomusicology and the potential of music and sound for environmental education
Ecomusicology is an interdisciplinary field drawing together scholars from sciences and humanities who share a research interest in the overlapping of music, culture, and nature. Human and non-human animals constantly rely on sonic signals to relate with other animals and the environment. Considering this auditory connection, and the contribution that ecocritical music and music about places may have in nurturing a sentiment of environmental stewardship, I propose an applied environmental education methodology that relies on participatory music making and critical listening to foster environmental awareness
Large strain computational modeling of high strain rate phenomena in perforating gun devices by Lagrangian/Eulerian FEM simulations
The present doctoral thesis deals with the study and the analysis of large strain and high strain rate behavior of materials and components. Theoretical, experimental and computational aspects are taken into consideration. Particular reference is made to the modeling of metallic materials, although other kinds of materials are considered as well. The work may be divided into three main parts.
The first part of the work consists in a critical review of the constitutive modeling of materials subjected to large strains and high to very high strain rates. Specific attention is paid to the opportunity of adopting so-called strength models and equations of state. Damage and failure modeling is discussed as well. In this part, specific interest is addressed to reviewing the so-called Johnson-Cook strength model, by critically highlighting its positive and negative aspects. One of the main tackled issue consists in a reasoned assessment of the various procedures adoptable in order to calibrate the parameters of the model. This phase is enriched and clarified by applying different calibration strategies to a real case, i.e. the evaluation of the model parameters for a structural steel. The consequences determined by each calibration approach are then carefully evaluated and compared.
The second part of the work aims at introducing a new strength model, that consists in a generalization of the Johnson-Cook model. The motivations for the introduction of this model are first exposed and discussed. The features of the new strength model are then described. Afterwards, the various procedures adoptable for the determination of the material parameters are presented. The new strength model is then applied to a real case, i.e. a structural steel as above, and the results are compared to those obtained from the original Johnson-Cook model. Comparing to that, the obtained outcomes show that the new model displays a better capacity in reproducing experimental data. Results are discussed and commented.
The third and final part of the work deals with an application of the studied topics to a real industrial case of interest. A device called perforating gun is analyzed in its structural problematics and critical aspects. This challenging application involves the modeling of several typologies of material, large strains, very high strain rate phenomena, high temperatures, explosions, hypervelocity impacts, damage, fracture and phase changes. In this regard, computational applications of the studied theories are presented and their outcomes are assessed and discussed. Several finite element techniques are considered. In particular, tridimensional Eulerian simulations are presented. The obtained results appear to be very promising in terms of the possibilities of a fruitful use in the design process of the device, in particular in order to achieve an optimization of its key features
An anomalous alloy: Y_x Si_{1-x}
We study via density functional-based molecular dynamics the structural and
dynamical properties of the rare earth silicon amorphous alloy Y_xSi_{1-x} for
x=0.093 and x=0.156. The Si network forms cavities in which a Y^{3+} cation is
entrapped. Its electrons are transferred to the Si network and are located in
the dangling bonds of the Si atoms that line the Y cavities. This leads to the
presence of low coordinated Si atoms that can be described as monovalent or
divalent anions. For x=0.156, the cavities touch each other and share Si atoms
that have two dangling bonds. The vibrational spectrum is similar to that of
amorphous Si. However, doping induces a shoulder at 70 cm^{-1} and a pronounced
peak at 180 cm^{-1} due to low coordinated Si.Comment: 4 pages, 4 figure
Use of Sugar Dispensers to Disrupt Ant Attendance and Improve Biological Control of Mealybugs in Vineyard
Planococcus ficus (Signoret) and Pseudococcus comstocki (Kuwana) (Hemiptera: Pseudococcidae)
are economically important pests occurring in vineyards, causing severe economic losses
for growers and compromising bunch production. The partial effectiveness of insecticides used in
controlling mealybug infestations as well as their high impact on the environment and on human
health have led to the research of alternative and sustainable control methods, including biological
control. Several natural enemies are reported to be effective against mealybugs, but their activity
may be hindered by tending ants. These social insects are known to exhibit a mutualistic relationship
with mealybugs, resulting in extremely aggressive behavior against beneficial insects. Consequently,
this study explored a method to mitigate ant attendance by means of sugar dispensers in order to
improve ecosystem services, as well as decrease mealybug infestation in vineyards. Field trials were
carried out in four commercial vineyards of Northern Italy infested by mealybugs, in which Anagyrus
vladimiri Triapitsyn (Hymenoptera: Encyrtidae) and Cryptolaemus montrouzieri Mulsant (Coleoptera:
Coccinellidae) were released as biological control agents. Our results showed that sugar dispensers
reduced ant activity and mealybug infestation, leading to a significant enhancement of ecosystem
services. The technique showed a great potential in boosting biological control against mealybugs in
field conditions, though the field application seemed to be labour intensive and needs to be replicated
for a multi-year evaluation
Incidence rate and risk factors for vaginal vault prolapse repair after hysterectomy
Our objective was to estimate the incidence and identify the risk factors for vaginal vault prolapse repair after hysterectomy. We conducted a case control study among 6,214 women who underwent hysterectomy from 1982 to 2002. Cases (n = 32) were women who required vaginal vault suspension following the hysterectomy through December 2005. Controls (n = 236) were women, randomly selected from the same cohort, who did not require pelvic organ prolapse surgery. The incidence of vaginal vault prolapse repair was 0.36 per 1,000 women-years. The cumulative incidence was 0.5%. Risk factors included preoperative prolapse (odds ratio (OR) 6.6; 95% confidence interval (CI) 1.5-28.4) and sexual activity (OR 1.3; 95% CI 1.0-1.5). Vaginal hysterectomy was not a risk factor when preoperative prolapse was taken into account (OR 0.9; 95% CI 0.5-1.8).Vaginal vault prolapse repair after hysterectomy is an infrequent event and is due to preexisting weakness of pelvic tissue
Efficacy and safety of trabeculectomy vs nonpenetrating surgical procedures: a systematic review and meta-analysis
To date, only a few studies have directly compared nonpenetrating surgery (NPS) and trabeculectomy (TE). Therefore, there is no strong evidence as to which surgical technique leads to the best results in terms of ocular hypotensive effect and safety
Molecular dynamics study of the fragmentation of silicon doped fullerenes
Tight binding molecular dynamics simulations, with a non orthogonal basis
set, are performed to study the fragmentation of carbon fullerenes doped with
up to six silicon atoms. Both substitutional and adsorbed cases are considered.
The fragmentation process is simulated starting from the equilibrium
configuration in each case and imposing a high initial temperature to the
atoms. Kinetic energy quickly converts into potential energy, so that the
system oscillates for some picoseconds and eventually breaks up. The most
probable first event for substituted fullerenes is the ejection of a C2
molecule, another very frequent event being that one Si atom goes to an
adsorbed position. Adsorbed Si clusters tend to desorb as a whole when they
have four or more atoms, while the smaller ones tend to dissociate and
sometimes interchange positions with the C atoms. These results are compared
with experimental information from mass abundance spectroscopy and the products
of photofragmentation.Comment: Seven two-column pages, six postscript figures. To be published in
Physical Review
Pilot scale validation campaign of gel dosimetry for pre-treatment quality assurance in stereotactic radiotherapy
Purpose: Complex stereotactic radiotherapy treatment plans require prior verification. A gel dosimetry system was developed and tested to serve as a high-resolution 3D dosimeter for Quality Assurance (QA) purposes.Materials and Methods: A modified version of a polyacrylamide polymer gel dosimeter based on chemical response inhibition was employed. Different sample geometries (cuvettes and phantoms) were manufactured for calibration and QA acquisitions. Irradiations were performed with a Varian Trilogy linac, and analyses of irradiated gel dosimeters were performed via MRI with a 1.5 T Philips Achieva at 1 mm3 or 2 mm3 isotropic spatial resolution. To assess reliability of polymer gel data, 54 stereotactic clinical treatment plans were delivered both on dosimetric gel phantoms and on the Delta4 dosimeter. Results from the two devices were evaluated through a global gamma index over a range of acceptance criteria and compared with each other.Results: A quantitative and tunable control of dosimetric gel response sensitivity was achieved through chemical inhibition. An optimized MRI analysis protocol allowed to acquire high resolution phantom dose data in time -frames of approximate to 1 h. Conversion of gel dosimeter data into absorbed dose was achieved through internal calibration. Polymer gel dosimeters (2 mm3 resolution) and Delta4 presented an agreement within 4.8 % and 2.7 % at the 3 %/1 mm and 2 %/2 mm gamma criteria, respectively.Conclusions: Gel dosimeters appear as promising tools for high resolution 3D QA. Added complexity of the gel dosimetry protocol may be justifiable in case of small target volumes and steep dose gradients
Complications associated with transobturator sling procedures: analysis of 233 consecutive cases with a 27 months follow-up
<p>Abstract</p> <p>Backround</p> <p>The transobturator tape procedure (TOT) is an effective surgical treatment of female stress urinary incontinence. However data concerning safety are rare, follow-up is often less than two years, and complications are probably underreported. The aim of this study was to describe early and late complications associated with TOT procedures and identify risk factors for erosions.</p> <p>Methods</p> <p>It was a 27 months follow-up of a cohort of 233 women who underwent TOT with three different types of slings (Aris<sup>®</sup>, Obtape<sup>®</sup>, TVT-O<sup>®</sup>). Follow-up information was available for 225 (96.6%) women.</p> <p>Results</p> <p>There were few per operative complications. Forty-eight women (21.3%) reported late complications including <it>de novo </it>or worsening of preexisting urgencies (10.2%), perineal pain (2.2%), <it>de novo </it>dyspareunia (9%), and vaginal erosion (7.6%). The risk of erosion significantly differed between the three types of slings and was 4%, 17% and 0% for Aris<sup>®</sup>, Obtape<sup>® </sup>and TVT-O<sup>® </sup>respectively (P = 0.001). The overall proportion of women satisfied by the procedure was 72.1%. The percentage of women satisfied was significantly lower in women who experienced erosion (29.4%) compared to women who did not (78.4%) (RR 0.14, 95% CI 0.05-0.38, P < 0.001).</p> <p>Conclusion</p> <p>Late post operative complications are relatively frequent after TOT and can impair patient's satisfaction. Women should be informed of these potential complications preoperatively and require careful follow-up after the procedure. Choice of the safest sling material is crucial as it is a risk factor for erosion.</p
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