5,670 research outputs found

    Testing a dissipative kinetic k-essence model

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    In this work, we present a study of a purely kinetic k-essence model, characterized basically by a parameter α\alpha in presence of a bulk dissipative term, whose relationship between viscous pressure Π\Pi and energy density ρ\rho of the background follows a polytropic type law Πρλ+1/2\Pi \propto \rho^{\lambda+1/2}, where λ\lambda, in principle, is a parameter without restrictions. Analytical solutions for the energy density of the k-essence field are found in two specific cases: λ=1/2\lambda=1/2 and λ=(1α)/2α\lambda=(1-\alpha)/2\alpha, and then we show that these solutions posses the same functional form than the non-viscous counterpart. Finally, both approach are contrasted with observational data from type Ia supernova, and the most recent Hubble parameter measurements, and therefore, the best values for the parameters of the theory are founds.Comment: 9 pages, 5 figures, accepted in EPJ

    Comparing Wearer DNA Sample Collection Methods for the Recovery of Single Source Profiles

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    Wearer DNA is the deposit of epithelial cells on clothing worn by an individual. Detection of the last individual to handle or wear an item is often an important and desirable determination in forensic science. The most commonly used collection methods for wearer DNA include swabbing and scraping. These often result in mixture profiles. Recently, adhesives have been introduced as a possible reliable method for the collection of biological evidence. The goal of the research was to compare the current collection methods of swabbing and scraping with a gel film called Gel-Pak ‘0’ which shares similar properties with adhesives. Gel-Pak ‘0’ has been previously studied in comparison to other adhesives for the collection of epithelial cells, and was shown to recover the top layer of loose particulate. This particulate had a tendency to be deposited by the individual who last came in contact with an item. Therefore, in comparison to the other two collection methods, Gel-Pak ‘0’ was hypothesized to recover single source profiles on clothing items from the most recent wearer. DNA analysis was performed on samples collected by the three methods from various clothing items including baseball hats, t-shirts, sweatpants, socks, and other items commonly submitted to crime labs for DNA analysis. The habitual wearer and the second/last wearer wore each item for a predetermined amount of time. The results of the research showed that Gel-Pak ‘0’ recovered a similar number of CODIS (local and national) eligible profiles as swabbing. However, coupled with the fact that it is time consuming, costly, and cannot be used on all surfaces, Gel-Pak ‘0’ was determined to not make for an effective collection method of the most recent wearer’s DNA. Therefore, Gel-Pak ‘0’ will not be considered for casework. Although Gel-Pak ‘0’ will not be further used, the results did reveal some trends that may shed light on how DNA analysts may approach wearer DNA cases. Swabbing had a tendency to yield smaller amounts of DNA in comparison to scraping, but obtain DNA from the last wearer of the piece of clothing more effectively than the other two methods. Scraping had a tendency to yield greater quantities of DNA, recovering more DNA from the habitual wearer due to its invasive nature. Revealing individuals who last wore an item can be of great importance in forensic science, and therefore, further research with various adhesives and gel films could be vital for solving forensic investigations

    Board of Vocational Nurse and Psychiatric Technician Examiners

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    Board of Vocational Nurse and Psychiatric Technician Examiners

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    Department of Real Estate

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    The Emergency of a Fourth Research Paradigm and Its Relationship with the Management of the 21st Century

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    A few thousand years ago our knowledge was based on the description of natural phenomena, which was supported on experimental science, a hundred years ago our knowledge evolved to the level of the definition of theories, which were supported by the theoretical sciences, recently , our knowledge was based on computational sciences, which used and continue to use the simulation of complex phenomena. Today, we have the fourth paradigm “The Science of Intensive Data”.That is, the large volume of data that flows through the networks, the information systems, the instruments in the factories, those that are captured directly or indirectly through interaction with the human being; flood the vast silos or data repositories. Therefore, corporations, companies and organizations have the great challenge to analyzing and processing this data, moving data to information and transforming information into knowledge.Therefore, the objective of this essay is to illustrate the emergence of the fourth research paradigm and its relationship with the management of the 21st century, its challenges and opportunities to develop a competitive strategy that ensures permanence in the changing business world
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