The role of magnetoplasmons in Casimir force calculations

In this paper we review the role of magneto plasmon polaritons in the Casimir force calculations. By applying an external constant magnetic field a strong optical anisotropy is induced on two parallel slabs reducing the reflectivity and thus the Casimir force. As the external magnetic field increases, the Casimir force decreases. Thus, with an an external magnetic field the Casimir force can be controlled.The calculations are done in the Voigt configuration where the magnetic field is parallel to the slabs. In this configuration the reflection coefficients for TE and TM modes do not show mode conversion.Comment: contribution to QFEXT09, Norman, Oklahoma 200

Pull-in control due to Casimir forces using external magnetic fields

We present a theoretical calculation of the pull-in control in capacitive micro switches actuated by Casimir forces, using external magnetic fields. The external magnetic fields induces an optical anisotropy due to the excitation of magneto plasmons, that reduces the Casimir force. The calculations are performed in the Voigt configuration, and the results show that as the magnetic field increases the system becomes more stable. The detachment length for a cantilever is also calculated for a cantilever, showing that it increases with increasing magnetic field. At the pull-in separation, the stiffness of the system decreases with increasing magnetic field.Comment: accepted for publication in App. Phys. Let

Van der Waals torque induced by external magnetic fields

We present a method for inducing and controlling van der Waals torques between two parallel slabs using a constant magnetic field. The torque is calculated using the Barash theory of dispersive torques. In III-IV semiconductors such as $InSb$, the effect of an external magnetic field is to induce an optical anisotropy, in an otherwise isotropic material, that will in turn induce a torque. The calculations of the torque are done in the Voigt configuration, with the magnetic field parallel to the surface of the slabs. As a case study we consider a slab made of calcite and a second slab made of $InSb$. In the absence of magnetic field there is no torque. As the magnetic field increases, the optical anisotropy of $InSb$ increases and the torque becomes different from zero, increasing with the magnetic field. The resulting torque is of the same order of magnitude as that calculated using permanent anisotropic materials when the magnetic fields is close to 1 T.Comment: to appear in Journal of Applied Physic

Evaluation of two toothbrushes prescriptions on the removal of plaque in patients with fixed orthodontic appliances

Indexación: Web of Science; ScieloLa aparatología empleada en los tratamientos de ortodoncia, favorece la retención de placa bacteriana y dificulta su eliminación por parte del paciente, aumentando el riesgo de desarrollar caries, manchas blancas y enfermedad periodontal. Diferentes cepillos dentales se han desarrollado para facilitar la mantención de una adecuada higiene oral en estos pacientes, sin embargo, se ha observado que los cepillos comunmente indicados (cepillo ortodóncico mas cepillo unipenacho), no siempre son bien manejados y difícilmente se usan ambos. El cepillo Cross Action Pro-Salud®, se ha presentado como una alternativa simple de usar y de transportar, por ser un único cepillo que combina las caracteristicas de los dos cepillos comunmente recomendados. Para evaluar la efectividad de este cepillo, en comparación con la prescripción convencional, se evaluaron 2 grupos, de 23 pacientes cada uno, portadores de aparatología fija. Un grupo utilizó la prescripción habitual y un segundo grupo utilizó cepillo Cross Action Pro-Salud®, por un período de 45 días. Los indices de higiene de O`leary, de placa en brackets y gingival modificado fueron registrados al inicio y 45 días después del uso diario de los cepillos antes mencionados. Se utilizó test-t para comparar los resultados obtenidos y se determinó que se produjo una disminución significativa en los tres indices de higiene, no existiendo diferencias en los resultados obtenidos entre ambas prescripciones. El cepillo Oral-B Cross-Action Pro-Salud® es una alternativa recomendable, ya que permite eliminar efectivamente la placa bacteriana en pacientes ortodónticos, y al ser un único cepillo, facilita y acorta el tiempo de cepillado.Orthodontic fixed appliances include elements that allow the accumulation of bacterial plaque, making tooth brushing more difficult and increasing the risk of developing caries, white spot lesions, and periodontal disease. Several toothbrushes designs have been developed to facilitate oral hygiene in orthodontic patients; however, it has been observed that most patients do not take enough time to brush using adequately both commonly prescribed toothbrushes (Oral-B End-Tufted® and Oral-B Orthodontic® brushes). Oral B Cross Action Pro-Health® has been presented as an alternative, easier to use and to transport. To assess the effectiveness of Cross Action Pro-Health® versus commonly prescribed toothbrushes, two randomly assigned groups of 23 orthodontic patients each, were evaluated. One group of patients used commonly prescribed toothbrushes and the second group used Cross Action Pro-Health®. O`Leary, modified gingival and Bracket plaque index were measured before and 45 days after the daily use of the two mentioned toothbrushes prescriptions. T-test was used to detect statistically significant differences among the brushes for each index. The results demonstrated a significant reduction of the three indexes with the daily use of Cross Action Pro-Health® and no differences were found versus commonly used prescription. Orthodontic patients may benefit from the use of a single brush prescription (Cross Action Pro-Health®), because effective plaque removal can be achieved easier and faster.http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0719-01072012000300002&nrm=is

First Detection of Mycobacterium ulcerans DNA in Environmental Samples from South America

The occurrences of many environmentally-persistent and zoonotic infections are driven by ecosystem changes, which in turn are underpinned by land-use modifications that alter the governance of pathogen, biodiversity and human interactions. Our current understanding of these ecological changes on disease emergence however remains limited. Buruli ulcer is an emerging human skin disease caused by the mycobacterium, Mycobacterium ulcerans, for which the exact route of infection remains unclear. It can have a devastating impact on its human host, causing extensive necrosis of the skin and underlying tissue, often leading to permanent disability. The mycobacterium is associated with tropical aquatic environments and incidences of the disease are significantly higher on floodplains and where there is an increase of human aquatic activities. Although the disease has been previously diagnosed in South America, until now the presence of M. ulcerans DNA in the wild has only been identified in Australia where there have been significant outbreaks and in western and central regions of Africa where the disease is persistent. Here for the first time, we have identified the presence of the aetiological agent's DNA in environmental samples from South America. The DNA was positively identified using Real-time Polymerase Chain Reaction (PCR) on 163 environmental samples, taken from 23 freshwater bodies in French Guiana (Southern America), using primers for both IS2404 and for the ketoreductase-B domain of the M. ulcerans mycolactone polyketide synthase genes (KR). Five samples out of 163 were positive for both primers from three different water bodies. A further nine sites had low levels of IS2404 close to a standard CT of 35 and could potentially harbour M. ulcerans. The majority of our positive samples (8/14) came from filtered water. These results also reveal the Sinnamary River as a potential source of infection to humans. © 2014 Morris et al

Satisfaction with Sex Life Scale: new psychometric evidence in a portuguese population

Accepted: 19 Oct. 2021 Introduction: In recent years, greater attention has been paid to research on sexual satisfaction because of its association with general well-being and increased interest in sexual and public health issues. Objectives: The objective of this study was to evaluate the psychometric properties of the Satisfaction with Sex Life Scale (SWSLS). Methods: 2,154 Portuguese individuals (M = 34.67 years, SD = 17.18) participated. Confirmatory factor analysis (CFA) and item response theory (IRT) were used. Specifically, the internal structure, reliability and factor invariance of the SWSLS were evaluated by sex and age, as well as the characteristics and performance of the items based on the IRT analysis. Results: The SWSLS Confirmatory Factor Analysis confirmed that a one-dimensional model fit the data well, both for the total sample and for each sex and age group. Furthermore, the SWSLS has adequate reliability for internal consistency. Factor invariance across sex and age was supported by confirmatory multigroup factor analysis. The graduated response model showed a good fit for the one-dimensional model, while the item and test information curves indicated that the SWSLS is more informative to identify high levels of sexual satisfaction. Conclusion: The SWSLS has adequate psychometric properties to measure general sexual satisfaction in the Portuguese population regardless of age and sex

Satisfaction with sex life scale: new psychometric evidence in a Portuguese population

Accepted: 19 Oct. 2021 Introduction: In recent years, greater attention has been paid to research on sexual satisfaction because of its association with general well-being and increased interest in sexual and public health issues. Objectives: The objective of this study was to evaluate the psychometric properties of the Satisfaction with Sex Life Scale (SWSLS). Methods: 2,154 Portuguese individuals (M = 34.67 years, SD = 17.18) participated. Confirmatory factor analysis (CFA) and item response theory (IRT) were used. Specifically, the internal structure, reliability and factor invariance of the SWSLS were evaluated by sex and age, as well as the characteristics and performance of the items based on the IRT analysis. Results: The SWSLS Confirmatory Factor Analysis confirmed that a one-dimensional model fit the data well, both for the total sample and for each sex and age group. Furthermore, the SWSLS has adequate reliability for internal consistency. Factor invariance across sex and age was supported by confirmatory multigroup factor analysis. The graduated response model showed a good fit for the one-dimensional model, while the item and test information curves indicated that the SWSLS is more informative to identify high levels of sexual satisfaction. Conclusion: The SWSLS has adequate psychometric properties to measure general sexual satisfaction in the Portuguese population regardless of age and sex

Single neutral pion production by charged-current νˉμ\bar{\nu}_\mu interactions on hydrocarbon at ⟨Eν⟩=\langle E_\nu \rangle = 3.6 GeV

Single neutral pion production via muon antineutrino charged-current interactions in plastic scintillator (CH) is studied using the \minerva detector exposed to the NuMI low-energy, wideband antineutrino beam at Fermilab. Measurement of this process constrains models of neutral pion production in nuclei, which is important because the neutral-current analog is a background for $\bar{\nu}_e$ appearance oscillation experiments. The differential cross sections for $\pi^0$ momentum and production angle, for events with a single observed $\pi^0$ and no charged pions, are presented and compared to model predictions. These results comprise the first measurement of the $\pi^0$ kinematics for this process.Comment: 6 pages, 5 figures, submitted to Physics Letters