26,299 research outputs found

    Is the transition redshift a new cosmological number?

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    Observations from Supernovae Type Ia (SNe Ia) provided strong evidence for an expanding accelerating Universe at intermediate redshifts. This means that the Universe underwent a transition from deceleration to acceleration phases at a transition redshift ztz_t of the order unity whose value in principle depends on the cosmology as well as on the assumed gravitational theory. Since cosmological accelerating models endowed with a transition redshift are extremely degenerated, in principle, it is interesting to know whether the value of ztz_t itself can be observationally used as a new cosmic discriminator. After a brief discussion of the potential dynamic role played by the transition redshift, it is argued that future observations combining SNe Ia, the line-of-sight (or "radial") baryon acoustic oscillations, the differential age of galaxies, as well as the redshift drift of the spectral lines may tightly constrain ztz_t, thereby helping to narrow the parameter space for the most realistic models describing the accelerating Universe.Comment: 12 pages, 5 figures. Some discussions about how to estimate the transition redshift have been added. New data by Planck and H(z) data have been mentioned. New references have been adde

    Short SULF1/SULF2 splice variants predominate in mammary tumours with a potential to facilitate receptor tyrosine kinase-mediated cell signalling

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    The relative roles of SULF1 and SULF2 enzymes in tumour growth are controversial, but short SULF1/SULF2 splice variants predominate in human mammary tumours despite their non-detectable levels in normal mammary tissue. Compared with the normal, the level of receptor tyrosine kinase (RTK) activity was markedly increased in triple-positive mammary tumours during later stages of tumour progression showing increased p-EGFR, p-FGFR1 and p-cMet activity in triple-positive but not in triple-negative tumours. The abundance of catalytically inactive short SULF1/SULF2 variants permits high levels of HS sulphation and thus growth driving RTK cell signalling in primary mammary tumours. Also observed in this study, however, was increased N-sulphation detected by antibody 10E4 indicating that not only 6-O sulphation but also N-sulphation may contribute to increased RTK cell signalling in mammary tumours. The levels of such increases in not only SULF1/SULF2 but also in pEGFR, pFGFR1, p-cMet and Smad1/5/8 signalling were further enhanced following lymph node metastasis. The over-expression of Sulf1 and Sulf2 variants in mammary tumour-derived MDA-MB231 and MCF7 cell lines by transfection further confirms Sulf1-/Sulf2-mediated differential modulation of growth. The short variants of both Sulf1 and Sulf2 promoted FGF2-induced MDA-MB231 and MCF7 in vitro growth while full-length Sulf1 inhibited growth supporting in vivo mammary tumour cell signalling patterns of growth. Since a number of mammary tumours become drug resistant to hormonal therapy, Sulf1/Sulf2 inhibition could be an alternative therapeutic approach to target such tumours by down-regulating RTK-mediated cell signalling

    Flow and acoustic characteristics of subsonic and supersonic jets from convergent nozzle

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    Acoustic and flow characteristics of subsonic and supersonic jets from convergent nozzle

    Postcard: I\u27m on the Hike to the Barbecue at Carlton, Kansas

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    This black and white printed postcard features an illustration of a man walking along railroad tracks towards a town. Text is printed on the top right of the card. Handwriting is on the bottom and back of the card.https://scholars.fhsu.edu/tj_postcards/1543/thumbnail.jp

    Unique Mass Texture for Quarks and Leptons

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    Texture specific quark mass matrices which are hermitian and hierarchical are examined in detail . In the case of texture 6 zeros matrices, out of sixteen possibilities examined by us, none is able to fit the low energy data (LED), for example, Vus=0.2196±0.0023V_{us} = 0.2196 \pm 0.0023, Vcb=0.0395±0.0017V_{cb} = 0.0395 \pm 0.0017, VubVcb=0.08±0.02\frac{V_{ub}}{V_{cb}} = 0.08 \pm 0.02, VtdV_{td} lies in the range 0.0040.0130.004 - 0.013 (PDG). Similarly none of the 32 texture 5 zeros mass matrices considered is able to reproduce LED. In particular, the latest data from LEP regarding Vub/Vcb(=0.093±0.016)|V_{ub}|/|V_{cb}|(=0.093\pm0.016) rules out all of them. In the texture 4 zeros case, we find that there is a unique texture structure for UU and DD mass matrices which is able to fit the data.Comment: 12 pages, LaTeX,some changes in the references,minor changes in the text,to appear in Phys Rev D(Rapid communications

    An Externally Coated Pyrex G-M Counter

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    Consumo voluntário: fatores relacionados com a degradação e passagem da forragem pelo rúmen.

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    Digestão a nível de rúmen. Dinâmica da passagem.bitstream/item/104713/1/Consumo-voluntario-fatores.pd

    Maximal violation of the CGLMP inequality for infinite dimensional states

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    We present a much simplified version of the CGLMP inequality for the 2 x 2 x d Bell scenario. Numerical maximization of the violation of this inequality over all states and measurements suggests that the optimal state is far from maximally entangled, while the best measurements are the same as conjectured best measurements for the maximally entangled state. For very large values of d the inequality seems to reach its minimal value given by the probability constraints. This gives numerical evidence for a tight quantum Bell inequality (or generalized Csirelson inequality) for the 2 x 2 x inf scenario.Comment: Introduction shortened, small changes, including new results for dimension of Hilbert space bigger than number of outcomes; 4 pages, 2 figure

    Charge neutralization in vacuum for non-conducting and isolated objects using directed low-energy electron and ion beams

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    We propose using ions and electrons of energy 1 eV–10 eV for neutralizing the charges on the non-conducting or isolated surfaces of high-sensitivity experiments. The mirror surfaces of the test masses of the laser interferometer gravitational observatory are used as an example of the implementation of this method. By alternatively directing beams of positive and negative charges towards the mirror surfaces, we ensure the neutralization of the total charge as well as the equalization of the surface charge distribution to within a few eV of the potential of the ground reference of the vacuum system. This method is compatible with operation in high vacuum, does not require measuring the potential of the mirrors and is expected not to damage sensitive optical surfaces

    Dynamic Shift from Cloud Computing to Industry 4.0: Eco-Friendly Choice or Climate Change Threat

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    Cloud computing utilizes thousands of Cloud Data Centres (CDC) and fulfils the demand of end-users dynamically using new technologies and paradigms such as Industry 4.0 and Internet of Things (IoT). With the emergence of Industry 4.0, the quality of cloud service has increased; however, CDC consumes a large amount of energy and produces a huge quantity of carbon footprint, which is one of the major drivers of climate change. This chapter discusses the impacts of cloud developments on climate and quantifies the carbon footprint of cloud computing in a warming world. Further, the dynamic transition from cloud computing to Industry 4.0 is discussed from an eco-friendly/climate change threat perspective. Finally, open research challenges and opportunities for prospective researchers are explored
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