1,345 research outputs found

    Charge Symmetry Breaking in 500 MeV Nucleon-Trinucleon Scattering

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    Elastic nucleon scattering from the 3He and 3H mirror nuclei is examined as a test of charge symmetry violation. The differential cross-sections are calculated at 500 MeV using a microsopic, momentum-space optical potential including the full coupling of two spin 1/2 particles and an exact treatment of the Coulomb force. The charge-symmetry-breaking effects investigated arise from a violation within the nuclear structure, from the p-nucleus Coulomb force, and from the mass-differences of the charge symmetric states. Measurements likely to reveal reliable information are noted.Comment: 5 page

    Atomic Properties of Lu+^+

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    Singly ionised Lutetium has recently been suggested as a potential clock candidate. Here we report a joint experimental and theoretical investigation of \ce{Lu^+}. Measurements relevant to practical clock operation are made and compared to atomic structure calculations. Calculations of scalar and tensor polarizabilities for clock states over a range of wavelengths are also given. These results will be useful for future work with this clock candidate.Comment: 12 pages, 5 figure

    Interplay between telecommunications and face-to-face interactions - a study using mobile phone data

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    In this study we analyze one year of anonymized telecommunications data for over one million customers from a large European cellphone operator, and we investigate the relationship between people's calls and their physical location. We discover that more than 90% of users who have called each other have also shared the same space (cell tower), even if they live far apart. Moreover, we find that close to 70% of users who call each other frequently (at least once per month on average) have shared the same space at the same time - an instance that we call co-location. Co-locations appear indicative of coordination calls, which occur just before face-to-face meetings. Their number is highly predictable based on the amount of calls between two users and the distance between their home locations - suggesting a new way to quantify the interplay between telecommunications and face-to-face interactions

    ''Remembering'' World War II and willingness to fight : sociocultural factors in the social representation of historical warfare across 22 societies

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    Students from 22 nations answered a survey on the most important events in world history. At the national level, free recalling and a positive evaluation of World War II (WWII) were associated with World Values Survey willingness to fight for the country in a war and being a victorious nation. Willingness to fight, a more benign evaluation of WWII, and recall of WWII were associ- ated with nation-level scores on power distance and low postmaterialism, suggesting that values stressing obedience and competition between nations are associated with support for collective violence, whereas values of expressive individualism are negatively related. Internal political vio- lence was unrelated to willingness to fight, excluding direct learning as an explanation of legit- imization of violence. Recall of wars in general (operationalized by WWI recall) was also unrelated to willingness to fight. Results replicate and extend Archer and Gartner’s classic study showing the legitimization of violence by war to the domain of collective remembering

    The somatostatin analogue octreotide confers sensitivity to rapamycin treatment on pituitary tumor cells

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    Rapamycin and its analogues have significant antiproliferative action against a variety of tumors. However, sensitivity to rapamycin is reduced by Akt activation that results from the ablative effects of rapamycin on a p70 S6K-induced negative feedback loop that blunts phosphoinositide 3-kinase (PI3K)-mediated support for Akt activity. Thus, sensitivity to rapamycin might be increased by imposing an upstream blockade to the PI3K/Akt pathway. Here, we investigated this model using the somatostatin analogue octreotide as a tool to decrease levels of activated Ser(473)-phosphorylated Akt (pAkt-Ser(473)) in pituitary tumor cells that express somatostatin receptors. Octreotide increased levels of phosphorylated insulin receptor substrate-1 that were suppressed by rapamycin, subsequently decreasing levels of pAkt-Ser(473) through effects on phosphotyrosine phosphatase SHP-1. Octreotide potentiated the antiproliferative effects of rapamycin in immortalized pituitary tumor cells or human nonfunctioning pituitary adenoma cells in primary cell culture, sensitizing tumor cells even to low rapamycin concentrations. Combined treatment of octreotide and rapamycin triggered G(1) cell cycle arrest, decreasing E2F transcriptional activity and cyclin E levels by increasing levels of p27/Kip1. These findings show that adjuvant treatment with a somatostatin analogue can sensitize pituitary tumor cells to the antiproliferative effects of rapamycin

    Un simulador de un modelo poblacional y su caja previsional

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    By building a system dynamics simulation platform from a demo-graphic model, this document analyzes the behavior of the population over time, as well as the population of the social security system. Simulation results show that there will be different types of problems in the future and will allow the Government to anticipate them. Due to the simplicity of its construction, it is very easy to implement in different regions with different precepts.Sociedad Argentina de Informática e Investigación Operativ

    3^3He Structure and Mechanisms of p3p^3He Backward Elastic Scattering

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    The mechanism of p3p^3He backward elastic scattering is studied. It is found that the triangle diagrams with the subprocesses pd3pd\to ^3Heπ0 \pi^0, pd3pd^*\to ^3Heπ0 \pi^0 and p(pp)3p(pp)\to^3Heπ+ \pi^+, where dd^* and pppp denote the singlet deuteron and diproton pair in the 1S0^1S_0 state, respectively, dominate in the cross section at 0.3-0.8 GeV, and their contribution is comparable with that for a sequential transfer of a npnp pair at 1-1.5 GeV. The contribution of the d+ppd^*+pp, estimated on the basis of the spectator mechanism of the p(NN)3p(NN)\to ^3Heπ \pi reaction, increases the p3p^3He3\to ^3Hep p cross section by one order of magnitude as compared to the contribution of the deuteron alone. Effects of the initial and final states interaction are taken into account.Comment: 17 pages, Latex, 4 postscript figures, expanded version, accepted by Physical Review
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