The aim of this paper is to study the possibility of improving the gamma/hadron discrimination in extensive air showers. For this purpose, the identification of hadronic extensive air showers is ...carried out by means of the detection of muons in water Cherenkov detectors (WCDs). Machine learning algorithms have proven to be useful in a wide variety of fields, and due to their outstanding performance in problems involving complex data, Convolutional Neural Networks (CNNs) have been used in the analysis of the signals measured by the WCDs. Taking simulated events, different approaches were proposed attending to the balance of the classes in the training stage. The results obtained are promising and show that machine learning algorithms provide a powerful tool for muon detection and gamma/hadron discrimination to be considered in future gamma-rays detectors like The Southern Wide-field Gamma-ray Observatory (SWGO) to be built in South America.
OBJECTIVEThe aim of this study is to prove the effectiveness of a low cost, artificial model for training of a laparoscopic urethrovesical anastomosis. MATERIALS AND METHODSThis study included ...urologists who attended specialised courses on laparoscopic radical prostatectomy (LRP) held during the period 2015 to 2017. They were divided into 2 groups according to their previous experience in laparoscopic surgery. The tasks performed on the artificial simulator were prostate resection, "task 1", and urethrovesical anastomosis, "task 2". Once these exercises were completed, the study participants filled in an anonymous questionnaire regarding their demographic data and experience level in laparoscopic surgery (LS). In addition, they gave their opinions about the didactic capacity of the artificial organ and evaluated its usefulness as a tool for LRP training. To demonstrate face and content validity, the participants judged the texture, consistency, morphology and evaluated its similarity to the real organ. The assessment was made with a five-point Likert scale. RESULTSThe students were divided into 2groups: 10 experts (Group E) and 12 novices (Group N). The only significant difference between the scores of novices and experts was regarding the inclusion of this tool in the training programs (Group E=5 points versus group N=4.4±0.59, P=.024). The experts' group rated all the items with higher scores than the novices' one. Regarding the general assessment of the simulation model, the novice participants gave an average score of 8.00±0.91 points out of 10, while the experts' group granted higher scores of 9.4±0,51. CONCLUSIONThis artificial model has shown to have an elevated face, content and construct validity, as well being an optimal didactic tool for training in the techniques of prostate resection and laparoscopic urethrovesical anastomosis.
According to recent conjectures on the existence of large extra dimensions in our universe, black holes could be produced during the interaction of Ultra High Energy Cosmic Rays with the atmosphere. ...However, and so far, the proposed signatures are based on statistical effects, not allowing identification on an event by event basis, and may lead to large uncertainties. In this note, events with a double bang topology, where the production and instantaneous decay of a microscopic black hole (first bang) is followed, at a measurable distance, by the decay of an energetic tau lepton (second bang) are proposed as an almost background free signature. The characteristics of these events and the capability of large cosmic ray experiments to detect them are discussed.
Applications of GEANT4 in astroparticle experiments Espirito-Santo, M.C.; Goncalves, P.; Pimenta, M. ...
IEEE transactions on nuclear science,
2004-Aug., 2004-08-00, 20040801, Letnik:
51, Številka:
4
Journal Article
Recenzirano
The GEANT4 Monte Carlo radiation transport toolkit, developed by the RD44 and GEANT4 Collaborations, aims to become a tool of generalized application in high energy physics, nuclear physics, ...astrophysics, and medical physics research. Due to its object-oriented design, GEANT4 is a distinct new approach for the development of flexible simulation applications. A wide energy range coverage for both electromagnetic and hadronic physics processes is offered. GEANT4 provides also an optical physics process category, allowing the production and propagation of scintillation and Cherenkov emitted light to be described. Such capabilities are well tailored for the requirements of the new generation of astrophysics experiments to be installed on the International Space Station, like EUSO and AMS. In this paper, the system architecture of a GEANT4 based simulation framework and its application to EUSO/ULTRA and AMS/RICH performance studies are presented.
The objective of our study was an assessment of outcome in a 1 year 'real world', prospective follow-up study of patients who were treated with paroxetine 20 mg plus pindolol 7.5 mg or paroxetine 20 ...mg plus placebo for 6 weeks. Eighty patients recruited to a double-blind placebo-controlled randomized 6 weeks study of paroxetine and pindolol were followed up for 6 months and interviewed after 1 year. A Kaplan-Meier survival analysis of the patients who relapsed having taken paroxetine and pindolol, compared with those who relapsed having taken paroxetine and placebo, shows that the pindolol group had a better clinical outcome. After 1 year patients who had responded to medication by 2 weeks had done better than the rest and they had been more compliant with medication for 6 months. There are indications that the earlier a patient responds to medication, the better the long-term outcome.
The aim of this study is to prove the effectiveness of a low cost, artificial model for training of a laparoscopic urethrovesical anastomosis.
This study included urologists who attended specialised ...courses on laparoscopic radical prostatectomy (LRP) held during the period 2015–2017. They were divided into 2 groups according to their previous experience in laparoscopic surgery.
The tasks performed on the artificial simulator were prostate resection, “task 1”, and urethrovesical anastomosis, “task 2”. Once these exercises were completed, the study participants filled in an anonymous questionnaire regarding their demographic data and experience level in laparoscopic surgery (LS). In addition, they gave their opinions about the didactic capacity of the artificial organ and evaluated its usefulness as a tool for LRP training.
To demonstrate face and content validity, the participants judged the texture, consistency, morphology and evaluated its similarity to the real organ. The assessment was made with a five-point Likert scale.
The students were divided into 2 groups: 10 experts (Group E) and 12 novices (Group N). The only significant difference between the scores of novices and experts was regarding the inclusion of this tool in the training programs (Group E=5 points versus group N=4.4±0.59, p=0.024). The experts’ group rated all the items with higher scores than the novices’ one. Regarding the general assessment of the simulation model, the novice participants gave an average score of 8.00±0.91 points out of 10, while the experts’ group granted higher scores of 9.4±0.51.
This artificial model has shown to have an elevated face, content and construct validity, as well being an optimal didactic tool for training in the techniques of prostate resection and laparoscopic urethrovesical anastomosis.
El objetivo de este estudio es demostrar la validez de un modelo inorgánico de bajo coste para el aprendizaje y entrenamiento de la anastomosis uretrovesical laparoscópica.
En este estudio participaron alumnos que asistieron a alguna de las ediciones de los cursos monográficos sobre prostatectomía radical laparoscópica (PRL) celebrados durante el periodo de 2015 a 2017. Estos participantes se dividieron en 2 grupos de acuerdo con su experiencia previa en cirugía laparoscópica (CL).
Las tareas que realizaron sobre el simulador inorgánico fueron la resección de la próstata, «tarea 1» y la anastomosis uretrovesical, «tarea 2». Una vez realizados estos ejercicios, los participantes del estudio completaron un cuestionario anónimo donde se recogieron sus datos demográficos y su nivel de experiencia en CL. Además, los asistentes realizaron una valoración de la capacidad didáctica del órgano sintético empleado, evaluando su utilidad como herramienta para la formación específica de PRL.
Para demostrar la validación aparente y de contenidos los participantes mostraron su opinión acerca de la textura, la consistencia, la morfología y la similitud del órgano con el paciente real. La valoración se realizó según una escala de Likert de 5 puntos.
Los alumnos se distribuyeron en 2grupos: 10 expertos (grupo E) y 12 noveles (grupo N). La única diferencia significativa entre las puntuación de noveles y de expertos fue respecto a la inclusión de esta herramienta en los programas de formación (grupo E=5 puntos frente al grupo N=4,4 ±0,59, p=0,024). Los expertos calificaron todas las cuestiones con mayores puntaciones que los noveles. En cuanto a la valoración general del modelo inorgánico, los participantes noveles dieron una calificación media de 8,00±0,91 puntos sobre 10, siendo superada por la valoración de los participantes del grupo de expertos, que dieron una puntuación media de 9,4±0,51.
Este modelo inorgánico ha demostrado poseer validez aparente, de contenidos y constructiva, además de ser una herramienta didáctica ideal para el aprendizaje y el entrenamiento de la resección prostática y de la anastomosis uretrovesical laparoscópica.
We describe a method for evaluating the value of increased cost of pharmacological augmentation that, taken for 6 weeks, accelerates the action of an antidepressant. We test the hypothesis that, if ...onset of action is taken into account, any added direct costs of the augmenting agent are offset by longer term cost effectiveness. Data to illustrate the method were based on a double-blind randomized placebo controlled study, in which 80 patients originally took part. Patients received the selective serotonin reuptake inhibitor (SSRI) antidepressant paroxetine and an augmenting agent (pindolol) or placebo. After 6 weeks, patients were offered SSRI alone on an open label basis for up to 6 months. At that point they were discharged to their general practitioner or local psychiatric services and subsequently assessed by us at one year. We have used techniques of decision analysis, cost effectiveness and cost benefit and have included a sensitivity analysis. The direct costs over one year of SSRI and augmenting agent, if taking the acceleration effect into account, represented greater cost effectiveness than the SSRI antidepressant alone. The cost effectiveness analysis was positive in both cases. We conclude that the direct costs of treatment are higher than those of previous calculated with SSRIs; but the rate of onset must be taken into account. The application of the model appears valid and useful, and may be used as part of the evaluation of other augmentation regimes.
Novel methods to reconstruct the slant depth of the maximum of the longitudinal profile ( Formula omitted) of high-energy showers initiated by gamma-rays as well as their energy ( Formula omitted) ...are presented. The methods were developed for gamma rays with energies ranging from a few hundred GeV to Formula omitted TeV. An estimator of Formula omitted is obtained, event-by-event, from its correlation with the distribution of the arrival time of the particles at the ground, or the signal at the ground for lower energies. An estimator of Formula omitted is obtained, event-by-event, using a parametrization that has as inputs the total measured energy at the ground, the amount of energy contained in a region near to the shower core and the estimated Formula omitted. Resolutions about Formula omitted and about Formula omitted for, respectively, Formula omitted and Formula omitted at Formula omitted energies are obtained, considering vertical showers. The obtained results are auspicious and can lead to the opening of new physics avenues for large wide field-of-view gamma-ray observatories. The dependence of the resolutions with experimental conditions is discussed.
Abstract
Novel methods to reconstruct the slant depth of the maximum of the longitudinal profile (
$$X_{\mathrm{max}}$$
X
max
) of high-energy showers initiated by gamma-rays as well as their energy ...(
$$E_0$$
E
0
) are presented. The methods were developed for gamma rays with energies ranging from a few hundred GeV to
$$\sim 10$$
∼
10
TeV. An estimator of
$$X_{\mathrm{max}}$$
X
max
is obtained, event-by-event, from its correlation with the distribution of the arrival time of the particles at the ground, or the signal at the ground for lower energies. An estimator of
$$E_0$$
E
0
is obtained, event-by-event, using a parametrization that has as inputs the total measured energy at the ground, the amount of energy contained in a region near to the shower core and the estimated
$$X_{\mathrm{max}}$$
X
max
. Resolutions about
$$40 \, (20)\,\mathrm{g/cm^2}$$
40
(
20
)
g
/
cm
2
and about
$$30 \, (20)\%$$
30
(
20
)
%
for, respectively,
$$X_{\mathrm{max}}$$
X
max
and
$$E_0$$
E
0
at
$$1 \, (10) \ \mathrm {TeV}$$
1
(
10
)
TeV
energies are obtained, considering vertical showers. The obtained results are auspicious and can lead to the opening of new physics avenues for large wide field-of-view gamma-ray observatories. The dependence of the resolutions with experimental conditions is discussed.
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