Effects of an extra Z′Z' gauge boson on the top quark decay t−−>cγt --> c \gamma

The effects of an extra $Z'$ gauge boson with family nonuniversal fermion couplings on the rare top quark decay $t --> c$gamma$are first examined in a model independent way and then in the minimal 331 model. It is found that the respective branching fraction is at most of the order of$10^{-8}$for$m_{Z'}=500$GeV and dramatically decreases for a heavier$Z'$boson. This results is in sharp contrast with a previous evaluation of this decay in the context of topcolor assisted technicolor models, which found that$B(t --> c \gamma)\sim 10^{-6}$for$m_{Z'}=1$ TeV.Comment: New paragraphs included to clarify our results, conclusion remains unchange

Perspectivas da bubalinocultura no Baixo Madeira no estado de Rondonia.

Estudo preliminar visando suprir deficiencia de carne e leite dos moradores das margens do Rio Madeira. Envolve aspectos relativos a bubalinocultura, operacoes que formam o sistema, producao de leite, instalacoes, comercializacao e sugestoes para o fomento da bubalinocultura.bitstream/item/55121/1/Circ.tecn-03-0001.pd

Dependence of Ga-doped ZnO thin film properties on different sputtering process parameters: Substrate temperature, sputtering pressure and bias voltage

This paper reports on the effects of different sputtering deposition process parameters (substrate temperature, sputtering pressure and bias voltage) on the electrical, optical, structural and morphological properties of gallium-doped ZnO (ZnO:Ga) of ~1 μm thick. These highly transparent and conductive films were deposited on glass surfaces by d.c. pulsed magnetron sputtering from a GZO (ZnO(95.5):Ga2O3(4.5)) ceramic target in an argon atmosphere. X-ray diffraction experiments show that all films have a hexagonal wurtzite structure with the [001] preferred crystallographic direction, and themorphology of the films (obtained fromscanning electron microscope analysis) is sensitive to the process parameters. All ZnO:Ga films have an average transmittance above 80% in the visible region, and the lowest electrical resistivity of 3.03 × 10−4 Ω·cm was achieved for the sample submitted to the lowest bias voltage (−40 V), which corresponds to a carrier concentration and a carrier mobility of 6.99 × 1020 cm−3 and 29.49 cm2 V−1 s−1, respectively. A high substrate temperature, high sputtering pressure and lownegative bias voltage (within the range of studied parameters) proved to be very promising on obtaining optimized ZnO:Ga films, ensuring suitable properties for application as transparent electrodes in photovoltaic cells.The authors acknowledge the funding from the Portuguese Innovation Agency (AdI), project reference WinDSC-21539, co-funded by FEDER/POFC

Cardiac Arrest in the Pediatric Population

Apresenta-se o caso clínico de uma criança de 10 anos com paragem cardíaca em repouso que foi reanimada, com sucesso. A investigação etiológica do acidente mostrou uma Cardiomiopatia Hipertrófica (CMH). Foi colocado um Cardiodesfibrilhador Implantável (CDI) para profilaxia secundária da Morte Súbita (MS). A Morte Súbita em idade pediátrica é uma situação rara, de muito mau prognóstico (sobrevida sem sequelas inferior a 5%) e com um impacto social significativo. A Cardiomiopatia Hipertrófica é uma causa conhecida de Morte Súbita, com possibilidade de prevenção. O caso apresentado serve para levantar questões sobre a necessidade e forma de estratégias para prevenir a MS de etiologica cardíaca em idade pediátrica

Characterization of microstructured multiwalled carbon nanotube/polydimethylsiloxane composites for piezoresistive sensing applications

Technological advancements in the field of flexible and printed electronics are creating a need for large-area sensors that can be embedded over different types of surfaces. Such sensors can be used to monitor physical signals over flexible, curved, or soft devices. Hence, it is herein proposed, a formulation to produce piezoresistive multiwalled carbon nanotube/polydimethylsiloxane (MWCNT/PDMS) composites with tunable electric properties for pressure sensing purposes. The composite is obtained through few manufacturing steps, avoiding the use of hazardous solvents. Different weight percentages of MWCNT dispersed in PDMS are evaluated and the results evidence that using 3.0 wt% of infill is sufficient to obtain highly sensitive sensors. To enhance the dispersion of the MWCNT and add microstructure to the composite, a system composed of a surfactant and foaming agent is used. Finally, pressure sensing units and arrays are printed and tested. The sensors present fast response, low hysteresis, repeatability, and a sensing range of 0–160 kPa. The composite is more sensitive to lower pressure and a maximum sensitivity of 8.0% kPa−1 is achieved for porous composites at pressure <10 kPa. Thanks to these characteristics, the sensors are successfully used in the development of a pressure sensing array and heartbeat sensor for proof of concept.This work has been supported by NORTE-06-3559-FSE-000018, integrated in the invitation NORTE-59-2018-41, aiming the Hiring of Highly Qualified Human Resources, co-financed by the Regional Operational Programme of the North 2020, thematic area of Competitiveness and Employment, through the European Social Fund (ESF), and by the scope of projects with references UIDB/05256/2020 and UIDP/05256/2020, financed by FCT—Fundação para a Ciência e Tecnologia, Portugal

Photocatalytic thin films coupled with polymeric microcapsules for the controlled-release of volatile agents upon solar activation

This work reports on the application of solar-activated photocatalytic thin films that allow the controlled-release of volatile agents (e.g., insecticides, repellents) from the interior of adsorbed polymeric microcapsules. In order to standardize the tests,a quantification of the inherent controlled-release of a particular volatile agent is determined by gas chromatography coupled to mass spectroscopy, so that an application can be offered to a wide range of supports from various industrial sectors, such as in textiles (clothing, curtains, mosquito nets). This technology takes advantage of the established photocatalytic property of titanium dioxide (TiO2) for the use as an active surface/site to promote the controlled-release of a specific vapor (volatile agentfrom within the aforementioned microcapsules.Portuguese FCT COMPETE scientific programs, with references NANO/NTec-CA/0046/2007 and PTDC/CTM-NAN/119979/201