11,938 research outputs found

    Inverse type II seesaw mechanism and its signature at the LHC and ILC

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    The advent of the LHC, and the proposal of building future colliders as the ILC, both programmed to explore new physics at the TeV scale, justifies the recent interest in studying all kind of seesaw mechanisms whose signature lies on such energy scale. The natural candidate for this kind of seesaw mechanism is the inverse one. The conventional inverse seesaw mechanism is implemented in an arrangement involving six new heavy neutrinos in addition to the three standard ones. In this paper we develop the inverse seesaw mechanism based on Higgs triplet model and probe its signature at the LHC and ILC. We argue that the conjoint analysis of the LHC together with the ILC may confirm the mechanism and, perhaps, infer the hierarchy of the neutrino masses.Comment: 24 pages, 22 figure

    Vacuum fluctuations of a scalar field near a reflecting boundary and their effects on the motion of a test particle

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    The contribution from quantum vacuum fluctuations of a real massless scalar field to the motion of a test particle that interacts with the field in the presence of a perfectly reflecting flat boundary is here investigated. There is no quantum induced dispersions on the motion of the particle when it is alone in the empty space. However, when a reflecting wall is introduced, dispersions occur with magnitude dependent on how fast the system evolves between the two scenarios. A possible way of implementing this process would be by means of an idealized sudden switching, for which the transition occurs instantaneously. Although the sudden process is a simple and mathematically convenient idealization it brings some divergences to the results, particularly at a time corresponding to a round trip of a light signal between the particle and the wall. It is shown that the use of smooth switching functions, besides regularizing such divergences, enables us to better understand the behavior of the quantum dispersions induced on the motion of the particle. Furthermore, the action of modifying the vacuum state of the system leads to a change in the particle energy that depends on how fast the transition between these states is implemented. Possible implications of these results to the similar case of an electric charge near a perfectly conducting wall are discussed.Comment: 17 pages, 8 figure

    Weeds associated with cotton crop and hosting whitefly.

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    The whitefly can be hosted by weeds and cause damage to cotton crops. The objective of this work was to identify which species of weeds among the floristic compositions occurring in the cotton crop are hosts of whiteflies (Bemisia tabaci biotype B). Bi-weekly evaluations were performed in a cotton area (FM 975 WS) in Sinop, Mato Grosso, Brazil, during the reproductive phase of the crop. An inventory square (0.25 m side) was randomly cast 15 times between the cotton rows. The weeds were cut close to the ground, conditioned and taken to the laboratory to identify the family and species, and to quantify the eggs and nymphs of whiteflies. Eleven families were detected, with the most frequent being Amaranthaceae (16.67%), Convolvulaceae (12.5%), Rubiaceae (12.5%) and Poaceae (12.5%). The most frequent species were Amaranthus spp. (13.79%) and Alternanthera tenella, Ipomea spp., Richardia brasiliensis and Eleusine indica, with 10.34% each. From the 15 collected species, the presence of whitefly eggs or nymphs was only not observed in Portulaca oleracea and E. indica. The highest incidence of B. tabaci occurred in Euphorbia heterophylla. The occurrence of these species should be monitored, so that the whitefly population does not interfere in the cotton fiber quality

    Tuned liquid dampers simulation for earthquake response control of buildings

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    This paper is focused on the study of an earthquake protection system, the Tuned Liquid Damper (TLD), which can, if adequately designed, reduce earthquake demands on buildings. This positive effect is accomplished taking into account the oscillation of the free surface of a fluid inside a tank (sloshing). The behaviour of an isolated Tuned Liquid Damper, subjected to a sinusoidal excitation at its base, with different displacement amplitudes, was studied by finite element analysis. The efficiency of the TLD in improving the seismic response of an existing building, representative of modern architecture buildings in southern European countries was also evaluated based on linear dynamic analyses

    Utilização do leite mamitico na alimentação de bezerras leiteiras.

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    Avaliar a viabilidade da utilização do leite produzido por tetas com mamite subclinica, tratadas com antibiótico na alimentação de bezerras leiteiras

    Sterile neutrino dark matter, CDMS-II and a light Higgs boson

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    We add a singlet right handed neutrino plus a charged and a neutral singlet scalars to the standard model. This extension includes a discrete symmetry such that we obtain a heavy sterile neutrino which couples only to the electron and the new scalars. In this sense the singlet neutrino does not mix with ordinary ones and thus has no effect on Big Bang Nucleosynthesis. However, such sterile neutrino can be in equilibrium with electroweak particles in the early Universe due to its couplings to electrons and also because the Higgs boson mixes with the singlet scalars. We obtain that the sterile neutrino constitutes a dark matter candidate and analyze its direct detection in the light of current experiments. Our results show that if such a sterile neutrino is realized in nature, and CDMS-II experiment confirms its positive signal, dark matter demands a rather light Higgs boson with new Physics at some 500 GeV scale.Comment: 16 pages, 13 figures, uses axodraw.st

    A Simple Realization of the Inverse Seesaw Mechanism

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    Differently from the canonical seesaw mechanism, which is grounded in grand unified theories, the inverse seesaw mechanism lacks a special framework that realizes it naturally. In this work we advocate that the 3-3-1 model with right-handed neutrinos has such an appropriate framework to accommodate the inverse seesaw mechanism. We also provide an explanation for the smallness of the μ\mu parameter and estimate the branching ratio for the rare lepton flavor violation process μeγ\mu \rightarrow e\gamma.Comment: About 14pages, no figures, basis corrected, to appear at the PR

    Urgent-Start Peritoneal Dialysis – a viable option? A case report and literature review

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    Background: Many patients with end -stage renal disease start renal replacement therapy in an unplanned manner. The vast majority initiate hemodialysis by a central venous catheter, since its use is more widespread and available. This technique is associated with a high risk of infection and damage of the vascular patrimony associated with the use of central veins. Urgent -start peritoneal dialysis comes as an alternative treatment for selected patients. Case report: A 55 -year -old woman with focal segmental glomerulosclerosis presented with a rapid decline of renal function and was given renal replacement therapy counselling and opted for peritoneal dialysis. Her chosen modality was postponed for one month due to early uremic symptoms, followed by hemodialysis start through a central venous catheter. During this period a sepsis due to central venous catheter infection occurred, implying four weeks of intravenous antibiotics. Discussion and Conclusion: Although there has been an increase in the number of publications on urgent -start peritoneal dialysis, showing that this technique has comparable results either to urgent -start hemodialysis and planned -start peritoneal dialysis, there still is some resistance to the use of this modality. Given the importance of this subject, this review aims to describe and summarize the available evidence on urgent -start peritoneal dialysis outcomes. Moreover, specific barriers are addressed. Its use is encouraged in hospitals where peritoneal dialysis is available, as an opportunity to improve chronic kidney disease patient management and transition to dialysis.info:eu-repo/semantics/publishedVersio
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