Susy QCD and High Energy Cosmic Rays 1. Fragmentation functions of Susy QCD

The supersymmetric evolution of the fragmentation functions (or timelike evolution) within N=1 $QCD$ is discussed and predictions for the fragmentation functions of the theory (into final protons) are given. We use a backward running of the supersymmetric DGLAP equations, using a method developed in previous works. We start from the usual QCD parameterizations at low energy and run the DGLAP back, up to an intermediate scale -assumed to be supersymmetric- where we switch-on supersymmetry. From there on we assume the applicability of an N=1 supersymmetric evolution (ESAP). We elaborate on possible application of these results to High Energy Cosmic Rays near the GZK cutoff.Comment: 36 pages, 12 fig

The NH2-terminal peptide of α–smooth muscle actin inhibits force generation by the myofibroblast in vitro and in vivo

Myofibroblasts are specialized fibroblasts responsible for granulation tissue contraction and the soft tissue retractions occurring during fibrocontractive diseases. The marker of fibroblast-myofibroblast modulation is the neo expression of α–smooth muscle actin (α-SMA), the actin isoform typical of vascular smooth muscle cells that has been suggested to play an important role in myofibroblast force generation. Actin isoforms differ slightly in their NH2-terminal sequences; these conserved differences suggest different functions. When the NH2-terminal sequence of α-SMA Ac-EEED is delivered to cultured myofibroblast in the form of a fusion peptide (FP) with a cell penetrating sequence, it inhibits their contractile activity; moreover, upon topical administration in vivo it inhibits the contraction of rat wound granulation tissue. The NH2-terminal peptide of α–skeletal actin has no effect on myofibroblasts, whereas the NH2-terminal peptide of β–cytoplasmic actin abolishes the immunofluorescence staining for this isoform without influencing α-SMA distribution and cell contraction. The FPs represent a new tool to better understand the specific functions of actin isoforms. Our findings support the crucial role of α-SMA in wound contraction. The α-SMA–FP will be useful for the understanding of the mechanisms of connective tissue remodeling; moreover, it furnishes the basis for a cytoskeleton-dependent preventive and/or therapeutic strategy for fibrocontractive pathological situations

Structural and functional characterisation of dioxolane A3, a new eicosanoid generated by cycooxygenase-1 in platelets

Platelet-derived eicosanoids play important signalling roles in haemostasis and innate immunity and have major medical implications in cardiovascular disease, inflammation and cancer. Therefore, identification and characterisation of novel platelet lipids is an important goal. Prior to my PhD, our group identified a novel cyclooxygenase-1 (COX-1) product generated by platelets upon agonist activation in an aspirin–sensitive manner. Preliminary structural data suggested this lipid to be 8-hydroxy-9,11-dioxolane eicosatrienoic acid (DXA3) (Aldrovandi, unpublished). However, this required further investigation and its biology was unknown. In this study, I undertook a detailed structural characterisation of DXA3. Using GC/MS, high resolution LC/MSn and UV enabled structural characterisation of the lipid. Through pharmacological studies on isolated platelets and using mutant COX-2 enzymes, I revealed a distinct enzymatic mechanism of COX where the dioxolane forms within the COX catalytic site, then a radical escapes from the enzyme to form DXA3 possibly via a peroxidase. I developed a quantitative assay and showed that DXA3 is generated in ng amounts by thrombin-activated platelets (human and murine) with 77% of DXA3 esterified to phosphatidylethanolamine (PE). In addition to platelets, I detected the lipid in human serum derived from whole blood following clot formation in vitro and the macrophage cell line RAW246.7 in response to calcium ionophore A23187 stimulation. Last, DXA3 stimulated expression of the integrin Mac-1 on human neutrophils. In conclusion, DXA3 represents a novel eicosanoid, generated by activated platelets that activates neutrophils and may play a role in early immune responses

Unlimited Paid Time Off Policies:Unlocking the Best and Unleashing the Beast

Unlimited paid time off policies are currently fashionable and widely discussed by HR professionals around the globe. While on the one hand, paid time off is considered a key benefit by employees and unlimited paid time off policies (UPTO) are seen as a major perk which may help in recruiting and retaining talented employees, on the other hand, early adopters reported that employees took less time off than previously, presumably leading to higher burnout rates. In this conceptual review, we discuss the theoretical and empirical evidence regarding the potential effects of UPTO on leave utilization, well-being and performance outcomes. We start out by defining UPTO and placing it in a historical and international perspective. Next, we discuss the key role of leave utilization in translating UPTO into concrete actions. The core of our article constitutes the description of the effects of UPTO and the two pathways through which these effects are assumed to unfold: autonomy need satisfaction and detrimental social processes. We moreover discuss the boundary conditions which facilitate or inhibit the successful utilization of UPTO on individual, team, and organizational level. In reviewing the literature from different fields and integrating existing theories, we arrive at a conceptual model and five propositions, which can guide future research on UPTO. We conclude with a discussion of the theoretical and societal implications of UPTO

The Exozodiacal Dust Problem for Direct Observations of ExoEarths

Debris dust in the habitable zones of stars - otherwise known as exozodiacal dust - comes from extrasolar asteroids and comets and is thus an expected part of a planetary system. Background flux from the Solar System's zodiacal dust and the exozodiacal dust in the target system is likely to be the largest source of astrophysical noise in direct observations of terrestrial planets in the habitable zones of nearby stars. Furthermore, dust structures like clumps, thought to be produced by dynamical interactions with exoplanets, are a possible source of confusion. In this paper, we qualitatively assess the primary impact of exozodical dust on high-contrast direct imaging at optical wavelengths, such as would be performed with a coronagraph. Then we present the sensitivity of previous, current, and near-term facilities to thermal emission from debris dust at all distances from nearby solar-type stars, as well as our current knowledge of dust levels from recent surveys. Finally, we address the other method of detecting debris dust, through high-contrast imaging in scattered light. This method is currently far less sensitive than thermal emission observations, but provides high spatial resolution for studying dust structures. This paper represents the first report of NASA's Exoplanet Exploration Program Analysis Group (ExoPAG).Comment: 21 pages, 5 figures, 2 tables. Accepted for publication in PASP 2012-06-0

KniMet: a pipeline for the processing of chromatography-mass spectrometry metabolomics data.

INTRODUCTION: Data processing is one of the biggest problems in metabolomics, given the high number of samples analyzed and the need of multiple software packages for each step of the processing workflow. OBJECTIVES: Merge in the same platform the steps required for metabolomics data processing. METHODS: KniMet is a workflow for the processing of mass spectrometry-metabolomics data based on the KNIME Analytics platform. RESULTS: The approach includes key steps to follow in metabolomics data processing: feature filtering, missing value imputation, normalization, batch correction and annotation. CONCLUSION: KniMet provides the user with a local, modular and customizable workflow for the processing of both GC-MS and LC-MS open profiling data

Nuclear Factor κB–dependent Gene Expression Profiling of Hodgkin's Disease Tumor Cells, Pathogenetic Significance, and Link to Constitutive Signal Transducer and Activator of Transcription 5a Activity

Constitutive nuclear nuclear factor (NF)-κB activity is observed in a variety of hematopoietic and solid tumors. Given the distinctive role of constitutive NF-κB for Hodgkin and Reed-Sternberg (HRS) cell viability, we performed molecular profiling in two Hodgkin's disease (HD) cell lines to identify NF-κB target genes. We recognized 45 genes whose expression in both cell lines was regulated by NF-κB. The NF-κB–dependent gene profile comprises chemokines, cytokines, receptors, apoptotic regulators, intracellular signaling molecules, and transcription factors, the majority of which maintain a marker-like expression in HRS cells. Remarkably, we found 17 novel NF-κB target genes. Using chromatin immunoprecipitation we demonstrate that NF-κB is recruited directly to the promoters of several target genes, including signal transducer and activator of transcription (STAT)5a, interleukin-13, and CC chemokine receptor 7. Intriguingly, NF-κB positively regulates STAT5a expression and signaling pathways in HRS cells, and promotes its persistent activation. In fact, STAT5a overexpression was found in most tumor cells of tested patients with classical HD, indicating a critical role for HD. The gene profile underscores a central role of NF-κB in the pathogenesis of HD and potentially of other tumors with constitutive NF-κB activation

Staying in touch while at work : Relationships between personal social media use at work and work-nonwork balance and creativity

Personal social media use at work is usually deemed counterproductive work behaviour reducing employee productivity. However, we hypothesized that it may actually help employees to coordinate work and nonwork demands, which should in turn increase work-related creativity. We used ecological momentary assessment across one working day with up to ten hourly measurements on 337 white-collar workers to measure personal social media use, work-nonwork balance and creativity, resulting in a total of 2244 hourly measurements. Multilevel modelling revealed that personal social media use was associated with better work-nonwork balance, but with lower levels of creativity between- and within-persons. Work-nonwork balance did not mediate the relationship between personal social media use and creativity. More research is needed to understand why employees use social media at work for personal purposes and how this affects their well-being and job performance