STUDY OF SECONDARY PARTICLES PRODUCED FROM HEAVY-ION INTERACTIONS

The study of secondary particles produced from heavy-ion interactions is important in heavy ion radiotherapy, space radiation protection, and shielding at accelerator facilities. This dissertation focuses on the study of secondary neutron production as they are of special concern among all secondary particles. The first part of this dissertation is the measurement of secondary neutrons created from 4He [helium] stopped in various target materials together with the model calculations accomplished by PHITS, FLUKA, and MCNP transport codes. The comparison results show that the physics models need improvements particularly in the predictions of 1) neutrons created from the 4He interactions at the high-energy end of the spectra at each angle for FLUKA’s and PHITS’s models, 2) the high-energy peaks at 0degree for all systems and all models, and 3) the low-energy neutrons at small angles for 230-MeV/nucleon [megaelectron volt per nucleon] 4He stopping in the light targets. However, the model calculations agree with the experiment data well at intermediate and large angles in intermediate and low energy regions. The second part is the benchmark of the neutron production cross section data with model calculations fulfilled by PHITS, FLUKA, and MCNP. The studied cases cover wide ranges of projectile species, beam energy and target nuclei mass. Some significant differences do appear not only among model calculations but also between measured data and calculations. In particular, LAQGSM03.03 implemented in MCNP6 significantly overestimates the high-energy peak in the forward direction in the light and very light system at 400 MeV/nucleon. RQMD implemented in FLUKA 2011.2c overestimates the neutron cross sections at intermediate energies in nearly all systems expect the lightest targets in our studies cases. The greatest inter-model difference appear on low-energy neutrons at forward angles in the system of 400-MeV/nucleon 132Xe (xenon) and copper target, and it is inferred that GEM implemented in PHITS 2.73 over-predicts neutrons produced from evaporation. The results of both experimental study and model calculations provide critical information for validation and verification of the current radiation transport codes used for simulating heavy-ion interactions and help lead to improvements in the physics models

Local density of states and scanning tunneling currents in graphene

We present exact analytical calculations of scanning tunneling currents in locally disordered graphene using a multimode description of the microscope tip. Analytical expressions for the local density of states (LDOS) are given for energies beyond the Dirac cone approximation. We show that the LDOS at the $A$ and $B$ sublattices of graphene are out of phase by $\pi$ implying that the averaged LDOS, as one moves away from the impurity, shows no trace of the $2q_F$ (with $q_F$ the Fermi momentum) Friedel modulation. This means that a STM experiment lacking atomic resolution at the sublattice level will not be able of detecting the presence of the Friedel oscillations [this seems to be the case in the experiments reported in Phys. Rev. Lett. {\bf 101}, 206802 (2008)]. The momentum maps of the LDOS for different types of impurities are given. In the case of the vacancy, $2q_F$ features are seen in these maps. In all momentum space maps, $K$ and $K+K^\prime$ features are seen. The $K+K^\prime$ features are different from what is seen around zero momentum. An interpretation for these features is given. The calculations reported here are valid for chemical substitution impurities, such as boron and nitrogen atoms, as well as for vacancies. It is shown that the density of states close to the impurity is very sensitive to type of disorder: diagonal, non-diagonal, or vacancies. In the case of weakly coupled (to the carbon atoms) impurities, the local density of states presents strong resonances at finite energies, which leads to steps in the scanning tunneling currents and to suppression of the Fano factor.Comment: 21 pages. Figures 6 and 7 are correctly displayed in this new versio

P and T Odd Asymmetries in Lepton Flavor Violating Tau Decays

We calculated the differential cross sections of the processes in which one of the pair created tau particles at an e^+ e^- collider decays into lepton flavor violating final states e.g. tau -> mu gamma, tau -> 3 mu, tau -> mu ee. Using the correlations between angular distributions of both sides of tau decays, we can obtain information on parity and CP violations of lepton flavor non-conserving interactions. The formulae derived here are useful in distinguishing different models, since each model of physics beyond the standard model predicts different angular correlations. We also calculate angular distributions of the major background process to tau -> l gamma search, namely tau -> l nu \bar{\nu} gamma, and discuss usefulness of the angular correlation for background suppression.Comment: 31 pages, 5 figure

New families of Q_B optimal saturated two-level main effects screening designs

In this paper, we study saturated two-level main effects designs which are commonly used for screening experiments. The Q_B criterion, which incorporates experimenters’ prior beliefs about the probability of factors being active is used to compare designs. We show that under priors with more weight on models of small size, p-efficient designs should be recommended; when models with more parameters are of interest, A-optimal designs would be better. We identify new classes of saturated main effects designs between these two designs under different priors. The way in which the choice of designs depends on experimenters’ prior beliefs is demonstrated for the cases when the number of runs N = 2 mod 4. A novel method of construction of Q_B-optimal designs using conference matrices is introduced. Complete families of optimal designs are given for N = 6; 10; 14; 18; 26; 30

Tau Lepton Physics: Theory Overview

The pure leptonic or semileptonic character of tau decays makes them a good laboratory to test the structure of the weak currents and the universality of their couplings to the gauge bosons. The hadronic tau decay modes constitute an ideal tool for studying low-energy effects of the strong interactions in very clean conditions; a well-known example is the precise determination of the QCD coupling from tau-decay data. New physics phenomena, such as a non-zero tau-neutrino mass or violations of (flavour / CP) conservation laws can also be searched for with tau decays.Comment: 20 pages, latex, 5 Postscript figures, uses espcrc2.sty, Invited Talk at the Fourth International Workshop on Tau Lepton Physics (TAU96), Colorado, September 199

THE BIOMECHANICALANALYSIS OF TAEKWONDO AXE-KICK IN SENIOR HIGH SCHOOL ATHLETIC

The purpose of this study was to investigate the biomechanical factors of the Taekwondo axe-kick and compare the differences between male and female athletes for timing kinematicsand kinetics. The data gained from 23 test subjects of the Taekwondo team from the junior high school (male:16, female:?). Base on the results and discussion of the study, we have reached the following conclusion: the average movement speed has significant difference between male and female groups. The average movement speed has significant positive correlation with the peak vertical ground reaction force (body weight), the peak front-rear ground reaction and impulse at the kicking leg. While the kicking leg attacked the target, the higher point of the kicking leg and the larger power at the peak tront-rear ground reaction force, the faster attacking velocity(the resultant of toe velocity) at the target

Associations among systemic blood pressure, microalbuminuria and albuminuria in dogs affected with pituitary- and adrenal-dependent hyperadrenocorticism

<p>Abstract</p> <p>Background</p> <p>Hypertension and proteinuria are medical complications associated with the multisystemic effects of long-term hypercortisolism in dogs with hyperadrenocorticism (HAC).</p> <p>Methods</p> <p>This study investigated the relationships among adrenocorticotropic hormone (ACTH)-stimulation test results, systemic blood pressure, and microalbuminuria in clinically-healthy dogs (n = 100), in dogs affected with naturally occurring pituitary-dependent (PDH; n = 40), or adrenal-dependent hyperadrenocorticism (ADH; n = 30).</p> <p>Results</p> <p>Mean systemic blood pressure was similar between clinically healthy dogs and dogs with HAC (<it>p </it>= 0.803). However the incidence of hypertension was highest in dogs with ADH (<it>p = 0.017</it>), followed by dogs with PDH, with the lowest levels in clinically healthy dogs (<it>p = 0.019</it>). Presence of microalbuminuria and albuminuria in clinically healthy dogs and dogs affected with HAC was significantly different (<it>p </it>< 0.001); incidences of albuminuria followed the same pattern of hypertension; highest incidence in dogs with ADH, and lowest level in clinically healthy dogs; but microalbuminuria showed a different pattern: clinically healthy dogs had highest incidences and dogs with ADH had lowest incidence. The presence of albuminuria was not associated with blood pressure values, regardless of whether dogs were clinically healthy or affected with ADH or PDH (<it>p </it>= 0.306).</p> <p>Conclusions</p> <p>Higher incidence of hypertension and albuminuria, not microalbuminuria was seen in dogs affected with HAC compared to clinically healthy dogs; incidence of hypertension and albuminuria was significantly higher in dogs affected with ADH compared to PDH. However, presence of albuminuria was not correlated with systemic blood pressure.</p

Comparación de la rugosidad superficial de restauraciones de resinas nanorelleno (Filtek Z350) según las diferentes técnicas de pulido: estudio in vitro

Tesis (Cirujano Dentista)Antecedentes: Actualmente existe una gran variedad de sistemas de pulido de resinas, pero sin un consenso respecto a qué técnica brinda menor rugosidad superficial, por lo que al momento de realizar el pulido, el odontólogo debe guiarse sólo por indicaciones del fabricante. No existen estudios con respecto a la relación de estas resinas nanorelleno (Filtek Z350) y la rugosidad superficial generada al combinar sistemas de pulido o al aplicar sellador de resina (Permaseal). Justificación: Se requiere mejorar la eficacia del pulido en las restauraciones de resina, para poder identificar la técnica que permita producir una superficie con menos rugosidad superficial, aumentando la longevidad del material y por ende el éxito del tratamiento. Objetivo: Determinar la efectividad de diferentes técnicas de pulido sobre la rugosidad superficial de resina nanorelleno (Filtek Z350). Material y Métodos: Estudio experimental in vitro, transversal y analítico, cuyas muestras estuvo constituida por 50 cilindros de resina nanorelleno (Filtek Z350). Se clasificaron en 10 grupos de estudio; un grupo control y 9 grupos tratados: Sof- Lex, KENDA C.G.I., Fresas de Pulido, Astrobrush, Permaseal, Sof-Lex + KENDA C.G.I, Sof-Lex + Astrobrush, KENDA + Astrobrush y Sof-Lex + KENDA C.G.I + Astrobrush. Se evaluó la rugosidad superficial de cada muestra 5 veces con el rugosímetro SURFTEST- III, Mitutoyo. Para el análisis de los datos, se utilizó un software estadístico SPSS v.24, evaluando la eficacia de pulido de los distintos sistemas, mediante técnicas de análisis descriptivos e inferenciales, con uso de T-Student para evaluación de diferencias de medias de las distintas muestras vs grupo control. Finalmente, se construyó una matriz con los distintos valores medios de las rugosidades superficiales obtenidas. 10 Resultados Observados: Al finalizar el estudio se pudo determinar que el sistema menos eficaz de pulido correspondió al grupo de fresas (0.99 μm) y el mejor sistema correspondió a los discos Sof-Lex (0.44 μm). El grupo Sof-Lex + Astrobrush, como combinación de sistemas de pulido, resultó el de menor rugosidad superficial (0.18 μm).Background: Now a days there are a lot of different polishing systems for resin composite, but there isn’t any consent about which system provides a lower superficial roughness, so it is necessary for the dentist to read the manufacturers indications. There are no studies that relates the superficial roughness of nanoparticles resin (Filtek Z350) with different combinations of polishing systems and the application of resin sealer (Permaseal). Justification: It is required to improve the efficacy of polishing, so that it can be identified the technique which provides less superficial roughness, increasing the material’s longevity and the success of the restoration. Purpose: Determine the effectiveness of different polishing techniques over the superficial roughness of nanofilled resin (Filtek Z350). Materials and Method: This experimental, transversal and analytic study, consisted in 50 samples of nanofilled resin (Filtek Z350) that were classified in to 10 groups: a control group and 9 groups that were treated with: Sof- Lex, KENDA C.G.I., Polishing drills, Astrobrush, Permaseal, Sof-Lex + KENDA C.G.I, Sof-Lex + Astrobrush, KENDA + Astrobrush or Sof-Lex + KENDA C.G.I + Astrobrush. The superficial roughness was measured 5 times per sample with the profilometer SURFTEST- III, Mitutoyo. To analyze the data, it was used the statistics software SPSS v.24, evaluating the polishing efficacy of different systems, it was applied descriptive and inferential studies techniques, using T-Student to evaluate the difference of medias of the different samples vs control group. Finally, it was constructed a matrix with the different middle value of the obtained superficial roughness. Observed Results: It was possible to determine that the worst polishing system was the polishing drill group (0.99 µm) and the best one was Sof-Lex Discs (0.44 µm). The Sof-Lex + Astrobrush group was the group with combination of systems that had the lowest superficial roughness (0.18 µm)