3,394 research outputs found

    Policies to Foster the Creation of Research-Based Spin-offs in Portugal

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    This paper presents a brief overview of the main government and institutional policies and mechanisms that promote and support (directly or indirectly) the creation of research-based spin-offs, as well as of the institutional changes that have been introduced to facilitate the commercial exploitation of results from academic research. In addition, there is an attempt to conduct a very preliminary assessment of some of the results achieved by these policies, within the limitations of the information available. It is concluded that the conditions for creating a firm that brings to the market knowledge or technology originating from academic research substantially improved in the last decade. Technology-based (and sometimes also scientific) entrepreneurship has been the object of several government policies and incentives and have also attracted the attention of other public and private actors, who launched a variety of programs to fund and otherwise support firm creation. This also coincided with institutional changes that facilitated the entrepreneurial initiatives of academic scientists. Although this appeared to have had positive effects in terms of the number of research-based spin-offs supported, the paper concludes, based on the limited data on results, that there is still work to do to improve the quality and effectiveness of the assistance provided. One step in this direction is a greater concentration and coordination of efforts.FC

    Synthetic wastewaters treatment by electrocoagulation to remove silver nanoparticles produced by different routes

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    International audienceNanoscience is a field that has stood out in recent years. The accurate long-term health and environmental risks associated with these emerging materials are unknown. Therefore, this work investigated how to eliminate silver nanoparticles (AgNPs) from synthetic effluents by electrocoagulation (EC) due to the widespread use of this type of nanoparticle (NP) in industry and its potential inhibition power over microorganisms responsible for biological treatment in effluent treatment plants. Synthesized AgNPs were studied via four different routes by chemical reduction in aqueous solutions to simulate the chemical variations of a hypothetical industrial effluent, and efficiency conditions of the EC treatment were determined. All routes used silver nitrate as the source of silver ions, and two synthesis routes were studied with sodium citrate as a stabilizer. In route I, sodium citrate functioned simultaneously as the reducing agent and stabilizing agent, whereas route II used sodium borohydride as a reducing agent. Route III used d-glucose as the reducing agent and sodium pyrophosphate as the stabilizer; route IV used sodium pyrophosphate as the stabilizing agent and sodium borohydride as the reducing agent. The efficiency of the EC process of the different synthesized solutions was studied. For route I, after 85 min of treatment, a significant decrease in the plasmon resonance peak of the sample was observed, which reflects the efficiency in the mass reduction of AgNPs in the solution by 98.6%. In route II, after 12 min of EC, the absorbance results reached the detection limit of the measurement instrument, which indicates a minimum reduction of 99.9% of AgNPs in the solution. During the 4 min of treatment in route III, the absorbance intensities again reached the detection limit, which indicates a minimum reduction of 99.8%. In route IV, after 10 min of treatment, a minimum AgNP reduction of 99.9% was observed. Based on these results, it was possible to verify that the solutions containing citrate considerably increased the necessary times required to eliminate AgNPs from the synthesized effluent, whereas solutions free of this reagent showed better results on floc formation and, therefore, are best for the treatment. The elimination of AgNPs from effluents by EC proved effective for the studied routes

    New Perspective on Galaxy Clustering as a Cosmological Probe: General Relativistic Effects

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    We present a general relativistic description of galaxy clustering in a FLRW universe. The observed redshift and position of galaxies are affected by the matter fluctuations and the gravity waves between the source galaxies and the observer, and the volume element constructed by using the observables differs from the physical volume occupied by the observed galaxies. Therefore, the observed galaxy fluctuation field contains additional contributions arising from the distortion in observable quantities and these include tensor contributions as well as numerous scalar contributions. We generalize the linear bias approximation to relate the observed galaxy fluctuation field to the underlying matter distribution in a gauge-invariant way. Our full formalism is essential for the consistency of theoretical predictions. As our first application, we compute the angular auto correlation of large-scale structure and its cross correlation with CMB temperature anisotropies. We comment on the possibility of detecting primordial gravity waves using galaxy clustering and discuss further applications of our formalism.Comment: 10 pages, 2 figures, accepted for publication in Physical Review

    A screening mechanism for extra W and Z gauge bosons

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    We generalize a previous construction of a fermiophobic model to the case of more than one extra WW and ZZ gauge bosons. We focus in particular on the existence of screening configurations and their implication on the gauge boson mass spectrum. One of these configurations allows for the existence of a set of relatively light new gauge bosons, without violation of the quite restrictive bounds coming from the ρNC\rho_{\rm NC} parameter. The links with Bess and degenerate Bess models are also discussed. Also the signal given here by this more traditional gauge extension of the SM could help to disentangle it from the towers of Kaluza-Klein states over WW and ZZ gauge bosons in extra dimensions.Comment: 23 pages, 1 figure, extended discussion on precision tests. To appear in International Journal of Modern Physics

    Pendeteksian Bit Error dalam Transmisi Data dengan Menerapkan Cyclic Redudancy Check

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    The communication path that will physically connect the two technologies conceptually works together such as cables. A special feature of a channel that resembles a cable is where the bits will be forwarded in the same order along with the bits sent. Data link layers have specific functions, this function includes starting from providing interfaces for services that are good for the network layer. Communication flows often make mistakes, sometimes having limited data rates and experiencing propagation delays other than zero between when bits are sent when the bit is received. This limitation is an implication of the importance of the efficiency of data transfer. Delivery of information in the telecommunications world will often occur errors in the data to be sent. This error is caused by a disturbance at the physical level, which is a disruption of the transmission line media, such as interference with electromagnetic radiation, cross communication, lightning or noise disturbance. This interference causes the information received does not match the information sent. The Cyclical Redundancy Check method, or CRC, is a method for handling error detection, this method uses binary numbers. The CRC data detection model is sent perframe consisting of a long row of bits for each frame
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