Spatial separation in a thermal mixture of ultracold 174^{174}Yb and 87^{87}Rb atoms

We report on the observation of unusually strong interactions in a thermal mixture of ultracold atoms which cause a significant modification of the spatial distribution. A mixture of $^{87}$Rb and $^{174}$Yb with a temperature of a few $\mu$K is prepared in a hybrid trap consisting of a bichromatic optical potential superimposed on a magnetic trap. For suitable trap parameters and temperatures, a spatial separation of the two species is observed. We infer that the separation is driven by a large interaction strength between $^{174}$Yb and $^{87}$Rb accompanied by a large three-body recombination rate. Based on this assumption we have developed a diffusion model which reproduces our observations

Lifetime Measurement of the 6s Level of Rubidium

We present a lifetime measurements of the 6s level of rubidium. We use a time-correlated single-photon counting technique on two different samples of rubidium atoms. A vapor cell with variable rubidium density and a sample of atoms confined and cooled in a magneto-optical trap. The 5P_{1/2} level serves as the resonant intermediate step for the two step excitation to the 6s level. We detect the decay of the 6s level through the cascade fluorescence of the 5P_{3/2} level at 780 nm. The two samples have different systematic effects, but we obtain consistent results that averaged give a lifetime of 45.57 +- 0.17 ns.Comment: 10 pages, 9 figure

Myeloid-derived suppressor cells are implicated in regulating permissiveness for tumor metastasis during mouse gestation.

Metastasis depends on the ability of tumor cells to establish a relationship with the newly seeded tissue that is conducive to their survival and proliferation. However, the factors that render tissues permissive for metastatic tumor growth have yet to be fully elucidated. Breast tumors arising during pregnancy display early metastatic proclivity, raising the possibility that pregnancy may constitute a physiological condition of permissiveness for tumor dissemination. Here we have shown that during murine gestation, metastasis is enhanced regardless of tumor type, and that decreased NK cell activity is responsible for the observed increase in experimental metastasis. Gene expression changes in pregnant mouse lung and liver were shown to be similar to those detected in premetastatic sites and indicative of myeloid cell infiltration. Indeed, myeloid-derived suppressor cells (MDSCs) accumulated in pregnant mice and exerted an inhibitory effect on NK cell activity, providing a candidate mechanism for the enhanced metastatic tumor growth observed in gestant mice. Although the functions of MDSCs are not yet understood in the context of pregnancy, our observations suggest that they may represent a shared mechanism of immune suppression occurring during gestation and tumor growth

Sphingosine 1-phosphate modulates antigen capture by murine langerhans cells via the S1P2 receptor subtype

Dendritic cells (DCs) play a pivotal role in the development of cutaneous contact hypersensitivity (CHS) and atopic dermatitis as they capture and process antigen and present it to T lymphocytes in the lymphoid organs. Recently, it has been indicated that a topical application of the sphingolipid sphingosine 1-phosphate (S1P) prevents the inflammatory response in CHS, but the molecular mechanism is not fully elucidated. Here we indicate that treatment of mice with S1P is connected with an impaired antigen uptake by Langerhans cells (LCs), the initial step of CHS. Most of the known actions of S1P are mediated by a family of five specific G protein-coupled receptors. Our results indicate that S1P inhibits macropinocytosis of the murine LC line XS52 via S1P2 receptor stimulation followed by a reduced phosphatidylinositol 3-kinase (PI3K) activity. As down-regulation of S1P2 not only diminished S1P-mediated action but also enhanced the basal activity of LCs on antigen capture, an autocrine action of S1P has been assumed. Actually, S1P is continuously produced by LCs and secreted via the ATP binding cassette transporter ABCC1 to the extracellular environment. Consequently, inhibition of ABCC1, which decreased extracellular S1P levels, markedly increased the antigen uptake by LCs. Moreover, stimulation of sphingosine kinase activity, the crucial enzyme for S1P formation, is connected not only with enhanced S1P levels but also with diminished antigen capture. These results indicate that S1P is essential in LC homeostasis and influences skin immunity. This is of importance as previous reports suggested an alteration of S1P levels in atopic skin lesions

Social presence and dishonesty in retail

Self-service checkouts (SCOs) in retail can benefit consumers and retailers, providing control and autonomy to shoppers independent from staff, together with reduced queuing times. Recent research indicates that the absence of staff may provide the opportunity for consumers to behave dishonestly, consistent with a perceived lack of social presence. This study examined whether a social presence in the form of various instantiations of embodied, visual, humanlike SCO interface agents had an effect on opportunistic behaviour. Using a simulated SCO scenario, participants experienced various dilemmas in which they could financially benefit themselves undeservedly. We hypothesised that a humanlike social presence integrated within the checkout screen would receive more attention and result in fewer instances of dishonesty compared to a less humanlike agent. This was partially supported by the results. The findings contribute to the theoretical framework in social presence research. We concluded that companies adopting self-service technology may consider the implementation of social presence in technology applications to support ethical consumer behaviour, but that more research is required to explore the mixed findings in the current study.<br/

Henry Wells Lawrence Memorial Lectures, Number 4

Fourth volume of a series of annual addresses given in honor of Connecticut College Professor of History, Henry Wells, Lawrence.Contents are as follows:Causes and Growth of the American Revolution, Bernhard KnollenbergReligion and the Sceptical Tradition, Franklin L. Baumer, Yale University Erasmus: The Scholar and the World, Myron P. Gilmore, Harvard Universityhttps://digitalcommons.conncoll.edu/ccbooks/1010/thumbnail.jp

Double Binds and Double Blinds: Evaluation Tactics in Critically Oriented HCI

Critically oriented researchers within Human-Computer Interaction (HCI) have fruitfully intersected design and critical analysis to engage users and designers in reflection on underlying values, assumptions and dominant practices in technology. To successfully integrate this work within the HCI community, critically oriented researchers have tactically engaged with dominant practices within HCI in the design and evaluation of their work. This paper draws attention to the ways that tactical engagement with aspects of HCI evaluation methodology shapes and bears consequences for critically oriented research. We reflect on three of our own experiences evaluating critically oriented designs and trace challenges that we faced to the ways that sensibilities about generalizable knowledge are manifested in HCI evaluation methodology. Drawing from our own experiences, as well as other influential critically oriented design projects in HCI, we articulate some of the trade-offs involved in consciously adopting or not adopting certain normative aspects of HCI evaluation. We argue that some forms of this engagement can hamstring researchers from pursuing their intended research goals and have consequences beyond specific research projects to affect the normative discourse in the field as a whole

Double Binds and Double Blinds: Evaluation Tactics in Critically Oriented HCI

Critically oriented researchers within Human-Computer Interaction (HCI) have fruitfully intersected design and critical analysis to engage users and designers in reflection on underlying values, assumptions and dominant practices in technology. To successfully integrate this work within the HCI community, critically oriented researchers have tactically engaged with dominant practices within HCI in the design and evaluation of their work. This paper draws attention to the ways that tactical engagement with aspects of HCI evaluation methodology shapes and bears consequences for critically oriented research. We reflect on three of our own experiences evaluating critically oriented designs and trace challenges that we faced to the ways that sensibilities about generalizable knowledge are manifested in HCI evaluation methodology. Drawing from our own experiences, as well as other influential critically oriented design projects in HCI, we articulate some of the trade-offs involved in consciously adopting or not adopting certain normative aspects of HCI evaluation. We argue that some forms of this engagement can hamstring researchers from pursuing their intended research goals and have consequences beyond specific research projects to affect the normative discourse in the field as a whole