177,386 research outputs found
Search for dark matter annihilation in the Wolf-Lundmark-Melotte dwarf irregular galaxy with HESS
No full textWe search for an indirect signal of dark matter through very high-energy γ rays from the Wolf-Lundmark-Melotte (WLM) dwarf irregular galaxy. The pair annihilation of dark matter particles would produce Standard Model particles in the final state such as γ rays, which might be detected by ground-based Cherenkov telescopes. Dwarf irregular galaxies represent promising targets as they are dark matter dominated objects with well-measured kinematics and small uncertainties on their dark matter distribution profiles. In 2018, the five-telescopes of the high energy stereoscopic system observed the dwarf irregular galaxy WLM for 18 hours. We present the first analysis based on data obtained from an imaging atmospheric Cherenkov telescope for this subclass of dwarf galaxy. As we do not observe any significant excess in the direction of WLM, we interpret the result in terms of constraints on the velocity-weighted cross section for dark matter pair annihilation «σv» as a function of the dark matter particle mass for various continuum channels, as well as the prompt γγ emission. For the τ+τ- channel, the limits reach a «σv» value of about 4×10-22 cm3 s-1 for a dark matter particle mass of 1 TeV. For the prompt γγ channel, the upper limit reaches a «σv» value of about 5×10-24 cm3 s-1 for a mass of 370 GeV. These limits represent an improvement of up to a factor 200, with respect to previous results for the dwarf irregular galaxies for TeV dark matter search
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Basement membrane heparan sulfate in atherogenesis and intimal hyperplasia
No full textCardiovascular disease due to atherosclerosis has become the leading cause of mortality in the world. Atherosclerosis is a progressive disease characterized by the accumulation of lipids, inflammatory cells, smooth muscle cells (SMCs) and extracellular matrix in the wall of large and medium-sized arteries. Surgical treatment of atherosclerosis cause mechanical injury to the vessel wall, which in many cases leads to restenosis and graft stenosis and recurrence of symptoms.Intimal SMC proliferation contributes to the stability of atherosclerotic plaques but it is also the main feature of intimal hyperplasia, which contributes to restenosis. It is therefore important to understand the mechanisms that control SMC growth in order to achieve a balanced healing response following interventions. This can be illustrated by the use of stents that elute anti-proliferative drugs, which has recently been associated with a higher risk of late stent thrombosis due to impaired intimal healing.Here, the role of basement membrane heparan sulfate (HS) in intimal hyperplasia and atherogenesis was investigated. Exogenously added heparin and HS are known inhibitors of SMC proliferation. However, the role of perlecan, which is the major arterial HS proteoglycan, in vascular disease was previously largely unknown. In vitro, the HS chains of perlecan lead to altered interactions between SMCs and fibronectin, possibly due to conformational changes in the fibronectin molecule. Such interactions may influence SMC function in atherogenesis and vascular repair processes. The use of transgenic mice expressing an HS-deficient perlecan showed increased SMC proliferation in vitro and increased intimal hyperplasia in vivo, confirming a growth inhibitory role for perlecan HS. A possible mechanism is decreased bioavailability of heparin-binding growth factors like FGF-2 at the cell surface due to sequestering in the basement membrane.In order to study the role of HS in atherogenesis the HS-deficient mice were cross-bred with apolipoprotein E null mice, which develop atherosclerosis. The results from that study indicate that the perlecan HS chains are pro-atherogenic in mice through increased lipoprotein retention, and the ability of HS to inhibit SMC growth may contribute to lesion instability. However, when binding and retention are not limiting factors, the perlecan HS chains may be anti-atherogenic by reducing endothelial permeability to lipoproteins. To investigate how perlecan can be pharmacologically regulated we explored the effect of all-trans-retinoic acid (AtRA) on perlecan expression in SMCs. AtRA was shown to up-regulate perlecan and the inhibition of SMC proliferation by AtRA is secondary to an increased expression of perlecan and dependent upon its HS chains.In summary, the role of basement membrane HS in vascular disease is complex. It may enhance lipoprotein retention, but also decrease endothelial permeability to lipoproteins. In addition, it can reduce restenosis, but maybe also cause plaque instability. This makes perlecan a difficult but very intriguing target for pharmacological interventions.List of scientific papersI. Lundmark K, Tran PK, Kinsella MG, Clowes AW, Wight TN, Hedin U (2001). Perlecan inhibits smooth muscle cell adhesion to fibronectin: role of heparan sulfate. J Cell Physiol. 188(1): 67-74. https://pubmed.ncbi.nlm.nih.gov/11382923II. Tran PK, Tran-Lundmark K, Soininen R, Tryggvason K, Thyberg J, Hedin U (2004). Increased intimal hyperplasia and smooth muscle cell proliferation in transgenic mice with heparan sulfate-deficient perlecan. Circ Res. 94(4): 550-8. Epub 2004 Jan 22 https://pubmed.ncbi.nlm.nih.gov/14739157III. Tran-Lundmark K, Tran PK, Paulsson-Berne G, Fridén V, Soininen R, Tryggvason K, Wight TN, Kinsella MG, Borén J, Hedin U (2008). Heparan sulfate in perlecan promotes mouse atherosclerosis: roles in lipid permeability, lipid retention and smooth muscle cell proliferation. Circulation Research. [Submitted]IV. Tran-Lundmark K, Tran PK, Rauch B, Ekstrand J, Wight TN, Hedin U, Kinsella MG (2008). Heparan sulfate chains on perlecan are required for the inhibition of arterial smooth muscle cell proliferation by all-trans-retinoic acid. [Submitted]</p
Letter from R. R. Zellick, Assistant Trust Officer, Anglo California National Bank of San Francisco, to Joseph R. Goodman, October 2, 1942
No full textLetter from R. R. Zellick, Assistant Trust Officer at The Anglo California National Bank of San Francisco, to Joseph R. Goodman, regarding property owned by Dave Tatsuno. Zellick mentions a dispute between current tenants and Tatsuno, and that Tatsuno has asked Goodman to help locate trustworthy tenants.Personal correspondence, organizational records, government documents, publications, and other papers created or collected by Joseph R. Goodman documenting the forced removal and incarceration of Japanese Americans during World War II, as well as organized resistance to incarceration. Included in the collection are records of the Japanese Young Men's Christian Association and the Japanese American Citizens' League in San Francisco, including papers of the Japanese YMCA's executive secretary Lincoln Kanai; Sakai family papers; Goodman's correspondence to and from Japanese American incarcerees, organizations opposing forced removal and incarceration of Japanese Americans, the War Relocation Authority, and others; publications, photographs, and ephemera from the Topaz Relocation Center, where Goodman taught high school; War Relocation Authority records and publications; and newspaper clippings, pamphlets, and reports about forced removal and incarceration created by various government, religious, and civic organizations, in California and nationwide
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Liftings for noncomplete probability spaces
No full textThe current state of knowledge concerning liftings for noncomplete probability spaces is discussed. This is a somewhat expanded version of the author's talk given at the 1991 Summer Conference on General Topology and Applications in Honor of Mary Ellen Rudin and Her Work.PT: S; CR: BURKE MR, IN PRESS P AM MATH S BURKE MR, 1991, ISRAEL J MATH, V73, P33 BURKE MR, 1992, ISRAEL J MATH, V79, P289 CARLSON T, THEOREM LIFTING CHRISTENSEN JPR, 1974, TOPOLOGY BOREL STRUC FREMLIN DH, 1989, HDB BOOLEAN ALGEBRAS, P877 INOESCUTULCEA A, 1966, 5TH P BERK S MATH ST, V2 IONESCUTULCEA A, 1967, CONTRIBUTIONS PROB 1, P63 IONESCUTULCEA A, 1969, TOPICS THEORY LIFTIN JECH TJ, 1978, SET THEORY JOHNSON RA, 1980, P AM MATH SOC, V80, P234 JUST W, IN PRESS T AM MATH S KUPKA J, 1983, INDIANA U MATH J, V32, P717 LOSERT V, 1983, LNM, V1080, P95 MAHARAM D, 1958, P AM MATH SOC, V9, P987 SHELAH S, 1983, ISRAEL J MATH, V45, P90 TALAGRAND M, 1982, P AM MATH SOC, V84, P379 VONNEUMANN J, 1931, CRELLES J MATH, V165, P109; NR: 18; TC: 0; J9: ANN N Y ACAD SCI; PG: 4; GA: BZ86BSource type: Electronic(1
Making or breaking organizational interventions : the role of leadership
No full textIntroduction: In the occupational health literature, organizational interventions have been recommended as an effective way to improve employee health and well-being. However, meta-analyses and literature reviews have shown that they often fail to achieve these intended outcomes. Owing to the organizational role of line managers, their actions have been suggested to be of particular importance to whether or not organizational interventions are implemented successfully. Still, we know relatively little about in what way line managers may facilitate or hinder implementation, and thereby organizational intervention outcomes.We also know relatively little about what causes line managers to facilitate or hinder organizational interventions, especially with regard to the contextual prerequisites for their behaviours. Increasing our knowledge about line managers’ leadership, and the antecedents to their leadership, during implementation of organizational interventions is therefore important in helping organizations to improve employee health and well-being.Aim: The overall aim of the present thesis was to investigate line managers’ leadership behaviours in conjunction with implementation of organizational interventions. More specifically, the aim was to investigate the association between line managers’ transformational leadership behaviours and implementation as well as intervention outcomes. An additional aim was to study the association between the contextual antecedents to their leadership behaviours during implementation.Methods: The present thesis consists of four quantitative studies investigating line managers’ leadership in conjunction with implementation of organizational interventions. Three organizational interventions were used as cases for these four studies. In Study I and II, line managers’ transformational leadership and change-supportive behaviours were related to an implementation outcome (employee use of a web-based system; Study I), and to distal intervention outcomes (employee self-rated health and work ability; Study II). In both studies, indirect effects of transformational leadership on these outcomes were examined, with line managers’ change-supportive behaviours as a mediator. These two studies were based on data from a web-based intervention conducted on both an individual and organizational level. In Study I, multilevel Poisson regression was used to analyse the data. A total of 216 white-collar employees, from 73 work units in 6 organizations, constituted the panel sample. In Study II, structural equation modelling was used to analyse data gathered from one of the organizations. A total of 180 employees constituted the panel sample in Study II.In Study III, the association between intervention-specific transformational leadership (IsTL) and employee’s perceptions of intervention fit (i.e., with context and individual needs) as an outcome of implementation was investigated. Furthermore, direct and indirect relationships between IsTL and intervention outcomes (i.e., change in intrinsic motivation and vigour) were studied. The data in Study III were gathered from an organizational intervention conducted at a process-industry plant, with 90 employees constituting the panel sample. In Study IV, the association between two contextual antecedents (i.e., span of control and employees’ readiness for change) and line managers’ IsTL and destructive leadership was examined using multilevel analysis. Data were gathered from another organizational intervention conducted at a process-industry plant, with 172 employees constituting the panel sample of the study.Results: In Study I and II, indirect relationships between line managers’ transformational leadership and studied outcomes were found, when mediated by line managers’ change-supportive behaviours. In Study III, IsTL was associated with intervention fit, which in turn was associated with change in intrinsic motivation. IsTL was indirectly related to change in intrinsic motivation when mediated by intervention fit. No relationship between IsTL and change in vigour was found, nor between intervention fit and change in vigour. However, when combining the strength of direct and indirect effects, line managers’ IsTL was statistically significantly related to change in vigour. In Study IV, span of control was associated with line managers’ IsTL and passive intervention-specific destructive leadership. Employees’ readiness for change was associated with line managers’ IsTL, and both passive and active intervention-specific destructive leadership.Conclusions: Taken together, the results of the four studies support previous findings suggesting that line managers’ behaviours in conjunction with implementation of organizational interventions are important to both implementation and intervention outcomes. The results also indicate that it is line managers’ intervention-specific behaviours that are directly associated with implementation and intervention outcomes, and therefore should be primarily focused on in organizational intervention process evaluations. Furthermore, the results illustrate how including a leadership theory-based evaluation of line managers’ behaviours (i.e., focusing on line managers’ exercise of social influence on employees) can provide additional information concerning how line managers’ facilitate implementation of organizational interventions. In addition, the results emphasize the importance of taking the contextual antecedents to line managers’ leadership behaviours into account, as these may help to explain their actions during an organizational intervention. From a practical perspective, in order to facilitate organizational interventions, assessing contextual conditions can help secure the resources needed for line managers to lead interventions effectively. Training and supporting line managers’ in exercising an IsTL may also increase the chances of intervention success.List of scientific papersI. Frykman, M., Lundmark, R., von Thiele Schwarz, U., Villaume, K., & Hasson, H. Line managers’ influence on employee usage of a web-based system for occupational health management. [Accepted] https://doi.org/10.1108/IJWHM-12-2017-0104 II. Lundmark, R., Hasson, H., von Thiele Schwarz, U., Hasson, D., & Tafvelin, S. (2017). Leading for change: Line managers’ influence on the outcomes of an occupational health intervention. Work & Stress. 1-21. https://doi.org/10.1080/02678373.2017.1308446 III. Lundmark, R., von Thiele Schwarz, U., Hasson, H., Stenling, A., & Tafvelin, S. (2018). Making it fit: Associations of line managers' behaviours with the outcomes of an organizational-level intervention. Stress and Health. 34(1), 163-174. https://doi.org/10.1002/smi.2770 IV. Lundmark, R., Nielsen, K., Hasson, H., von Thiele Schwarz, U., & Tafvelin, S. No leader is an island: Contextual antecedents to line managers’ constructive and destructive leadership during an organisational intervention. [Submitted]</p
Cooperative but distinct early co-signaling events originate from ERBB2 and ERBB1 receptors upon trastuzumab treatment in breast cancer cells
No full textERBB2 receptor belongs to the ERBB tyrosine kinase receptor family. At variance to the other family members, ERBB2 is a constitutively active orphan receptor. Upon ligand binding and activation, ERBB receptors form homo-or hetero-dimers with the other family members, including ERBB2, promoting an intracellular signaling cascade. ERBB2 is the preferred dimerization partner and ERBB2 heterodimers signaling is stronger and longer acting compared to heterodimers between other ERBB members. The specific contribution of ERBB2 in heterodimer signaling is still undefined. Here we report the formation of circular dorsal ruffles (CDRs) upon treatment of the ERBB2-overexpressing breast cancer cell lines SK-BR-3 and ZR751 with Trastuzumab, a therapeutic humanized monoclonal antibody directed against ERBB2. We found that in SK-BR-3 cells Trastuzumab leads to surface redistribution of ERBB2 and ERBB1 in CDRs, and that the ERBB2-dependent ERK1/2 phosphorylation and ERBB1 expression are both required for CDR formation. In particular, in these cells CDR formation requires activation of both the protein regulator of actin polymerization N-WASP, mediated by ERK1/2, and of the actin depolymerizing protein cofilin, mediated by ERBB1. Furthermore, we suggest that this latter event may be inhibited by the negative cell motility regulator p140Cap, as we found that p140Cap overexpression led to cofilin deactivation and inhibition of CDR formation. In conclusion, here we show for the first time an ERBB2-specific signaling contribution to an ERBB2/ERBB1 heterodimer, in the activation of a complex biological process such as the formation of CDRs
- …
