Chiral Models in Noncommutative N=1/2 Four Dimensional Superspace

We derive the component Lagrangian for a generic N=1/2 supersymmetric chiral model with an arbitrary number of fields in four space-time dimensions. We then investigate a toy model in which the deformation parameter modifies the undeformed potential near the origin of the field space in a way which suggests possible physical applications.Comment: Final version to appear in Physical Review D. We have added a new section in which we show that our component action can be resummed. The final answer takes a simple compact form. We also show how differences emerge for the modified Kaehler structure with respect to the ones found in the literature. We have also added two reference

Top physics at CDF

Recent results in top physics at CDF presented at the Lake Louise Winter Institute 2008 are discussed, including updates to the top mass, single top search, a search for flavor changing neutral currents in top decay, and W-helicity measurements. Several newer measurements are also presented including the forward-backward asymmetry, the t{bar t} differential cross-section d{sigma}/dM{sub t{bar t}}, and a search for top pair production from massive gluons. Most of the discussed measurements utilize close to 2 fb{sup -1} of data collected at CDF

Heart rate sensitivity of virtual non-contrast calcium scores derived from photon counting detector CT data: a phantom study

Purpose To assess the reliability of virtual non-contrast (VNC) derived coronary artery calcium quantities in relation to heart rate and the VNC algorithm used compared to reference true non-contrast (TNC), considering several clinically established acquisition modes. Material and methods An ad hoc built coronary phantom containing four calcified lesions and an iodinated lumen was scanned using three cardiac acquisition modes three times within an anthropomorphic cardiac motion phantom simulating different heart rates (0, 60, 80, 100 bpm) and reconstructed with a conventional (VNCconv) and a calcium-sensitive (VNCpc) VNC algorithm. TNC reference was scanned at 0 bpm with non-iodinated lumen. Calcium scores were assessed in terms of number of lesions detected, Agatston and volume scores and global noise was measured. Paired t-test and Wilcoxon test were performed to test measurements for significant difference. Results For both VNC algorithms used, calcium levels or noise were not significantly affected by heart rate. Measurements on VNCpc reconstructions best reproduced TNC results, but with increased variability (Agatston scores at 0 bpm for TNC, VNCconv, and VNCpc were 47.1 ± 1.1, 6.7 ± 2.8 (p  0.05), respectively). VNC reconstructions showed lower noise levels compared to TNC, especially for VNCpc (noiseheart on TNC, VNCconv and VNCpc at 0 bpm was 5.0 ± 0.4, 4.5 ± 0.2, 4.2 ± 0.2). Conclusion No significant heart rate dependence of VNC-based calcium scores was observed in an intra-reconstruction comparison. VNCpc reproduces TNC scores better than VNCconv without significant differences and decreased noise, however, with an increasing average deviation with rising heart rates. VNC-based CACS should be used with caution as the measures show higher variability compared to reference TNC and therefore hold the potential of incorrect risk categorization

Detection of a Specific Inhibitor of Interleukin 1 in Sera of UVB-Treated Mice

It was recently demonstrated that murine keratinocytes upon irradiation with ultraviolet (UV) light release an immunosuppressive cytokine which blocks the biological activity of interleukin 1 (IL 1). This epidermal cell derived inhibitor (EC-contra IL 1) exhibits a molecular weight of 40 kD and a pI of approximately 9.0. EC-contra IL 1 in vivo possibly may penetrate through the basal lamina and subsequently cause systemic immunosuppression following UV-exposure. In the present study, we tested whether EC-contra IL 1 can also be detected in vivo. Serum samples obtained from total body UV-exposed mice were subjected to HPLC gel filtration and tested for IL 1 inhibitory activity. While a non-specific high molecular weight (300 kD) suppressor factor was detected in sera of both UV-exposed and sham treated control mice, a specific IL 1 inhibitor exhibiting a molecular weight of 40 kD was observed only in sera of UV-exposed mice. This cytokine named serum-contra IL 1 was maximally released 24 h after UV-exposure, exhibited a pI of 9.0, and blocked the activity of natural as well as recombinant interleukin 1 in a dose dependent manner. Serum-contra IL 1 did not suppress interleukin 2 or interleukin 3 and did not inhibit spontaneous cell proliferation. The present biochemical and biologic data suggest that serum-contra IL 1 and EC-contra IL 1 appear to be closely related if not identical. These observations therefore indicate that keratinocytes upon UV-irradiation in vivo release EC-contra IL 1 which may at least partly be responsible for the immunosuppression following UV-exposure

A relational perspective on how and when follower attachment style impacts job performance: The moderating role of leader neuroticism

We integrate insights from attachment theory and relational leadership to develop a novel interpersonal explanation of why, how and when followers' attachment anxiety and avoidance impact performance. Drawing on the attachment system dynamics model, we posit that attachment avoidance will be negatively related to LMX quality, whereas attachment anxiety will be positively related to LMX ambivalence. Furthermore, we predict that followers' anxious (and avoidant) attachment styles will interact with leader neuroticism leading to a hyperactivation (deactivation) of the attachment system, manifesting in greater LMX ambivalence (and lower LMX quality). Across three studies, we found consistent evidence for a positive relationship between follower attachment anxiety and LMX ambivalence, as well as an indirect effect between attachment anxiety and job performance. Leader neuroticism was especially likely to induce LMX ambivalence and, in turn, undermine job performance in anxiously attached followers. Attachment avoidance, although unaffected by leader neuroticism, was negatively related to LMX quality across all three studies and demonstrated an indirect effect on job performance in Study 3. Overall, our findings shed light on the unique explanatory power of relational mechanisms, beyond previously examined intrapersonal mechanisms, for understanding the attachment style–performance relationship as well as the role that leader characteristics play in triggering the attachment system in anxious followers

X-ray spectroscopy and photometry of the long-period polar AI Tri with XMM-Newton

Context. The energy balance of cataclysmic variables with strong magnetic fields is a central subject in understanding accretion processes on magnetic white dwarfs. With XMM-Newton, we perform a spectroscopic and photometric study of soft X-ray selected polars during their high states of accretion. Aims. On the basis of X-ray and optical observations of the magnetic cataclysmic variable AI Tri, we derive the properties of the spectral components, their flux contributions, and the physical structure of the accretion region in soft polars. Methods. We use multi-temperature approaches in our xspec modeling of the spectra to describe the physical conditions and the structures of the post-shock accretion flow and the accretion spot on the white-dwarf surface. In addition, we investigate the accretion geometry of the system by a timing analysis of the photometric data. Results. Flaring soft X-ray emission from the heated surface of the white dwarf dominates the X-ray flux during roughly 70% of the binary cycle. This component deviates from a single black body and can be described by a superimposition of mildly absorbed black bodies with a Gaussian temperature distribution. In addition, weaker hard X-ray emission is visible nearly all the time. The spectrum from the cooling post-shock accretion flow is most closely fitted by a combination of thermal plasma mekal models with temperature profiles adapted from prior stationary two-fluid hydrodynamic calculations. The soft X-ray light curves show a dip during the bright phase, which can be interpreted as self-absorption in the accretion stream. Phase-resolved spectral modeling supports the picture of one-pole accretion and self-eclipse. One of the optical light curves corresponds to an irregular mode of accretion. During a short XMM-Newton observation at the same epoch, the X-ray emission of the system is clearly dominated by the soft component.Comment: A&A, in press; 11 pages, 9 figures, 3 table

The Meaningfulness of Effect Sizes in Psychological Research: Differences Between Sub-Disciplines and the Impact of Potential Biases

Effect sizes are the currency of psychological research. They quantify the results of a study to answer the research question and are used to calculate statistical power. The interpretation of effect sizes—when is an effect small, medium, or large?—has been guided by the recommendations Jacob Cohen gave in his pioneering writings starting in 1962: Either compare an effect with the effects found in past research or use certain conventional benchmarks. The present analysis shows that neither of these recommendations is currently applicable. From past publications without pre-registration, 900 effects were randomly drawn and compared with 93 effects from publications with pre-registration, revealing a large difference: Effects from the former (median r = 0.36) were much larger than effects from the latter (median r = 0.16). That is, certain biases, such as publication bias or questionable research practices, have caused a dramatic inflation in published effects, making it difficult to compare an actual effect with the real population effects (as these are unknown). In addition, there were very large differences in the mean effects between psychological sub-disciplines and between different study designs, making it impossible to apply any global benchmarks. Many more pre-registered studies are needed in the future to derive a reliable picture of real population effects