226 research outputs found
The estimation of black-hole masses in distant radio galaxies
We have estimated the masses of the central supermassive black holes of 2442
radio galaxies froma catalog compiled using data from the NED, SDSS, and CATS
databases. Mass estimates based on optical photometry and radio data are
compared. Relationships between the mass of the central black hole
and the redshift are constructed for both wavelength ranges. The
distribution of the galaxies in these diagrams and systematic effects
influencing estimation of the black-hole parameters are discussed.
Upperenvelope cubic regression fits are obtained using the maximum estimates of
the black-hole masses. The optical and radio upper envelopes show similar
behavior, and have very similar peaks in position, , and
amplitude, = 9.4. This is consistent with a model in which the
growth of the supermassive black holes is self-regulating, with this redshift
corresponding to the epoch when the accretion-flow phase begins to end and the
nuclear activity falls off.Comment: 8 pages, 6 figure
Geochemistry and petrogenesis of the Etendeka volcanic rocks from SWA Namibia
The volcanic rocks of the Etendeka Formation from north-west SWA/Namibia have a present-day coverage of 70,000 kmÂČ and comprise a series of interbedded basalts, latites and quartz latites, together with four varieties of intrusive dolerite. Apart from one group of dolerites (regional dolerites) which have mineralogical and geochemical similarities to the Lesotho Formation lavas from the Central area, the Etendeka volcanics differ from all other Karoo volcanics by virtue of their Cretaceous age, stratigraphy, mineralogy, geochemistry, and range in mineralogical, elemental and isotopic compositions for the basaltic rocks
PICALM modulates autophagy activity and tau accumulation.
Genome-wide association studies have identified several loci associated with Alzheimer's disease (AD), including proteins involved in endocytic trafficking such as PICALM/CALM (phosphatidylinositol binding clathrin assembly protein). It is unclear how these loci may contribute to AD pathology. Here we show that CALM modulates autophagy and alters clearance of tau, a protein which is a known autophagy substrate and which is causatively linked to AD, both in vitro and in vivo. Furthermore, altered CALM expression exacerbates tau-mediated toxicity in zebrafish transgenic models. CALM influences autophagy by regulating the endocytosis of SNAREs, such as VAMP2, VAMP3 and VAMP8, which have diverse effects on different stages of the autophagy pathway, from autophagosome formation to autophagosome degradation. This study suggests that the AD genetic risk factor CALM modulates autophagy, and this may affect disease in a number of ways including modulation of tau turnover.We are grateful for funding from a Wellcome Trust Principal Research Fellowship
(D.C.R.), a Wellcome Trust/MRC Strategic Grant on Neurodegeneration (D.C.R.,
C.J.Oâ.K.), a Wellcome Trust Strategic Award to Cambridge Institute for Medical
Research, Wellcome Trust Studentship (E.Z.), the Alzheimerâs disease Biomedical
Research Unit and Addenbrookeâs Hospital, the Tau Consortium, a fellowship from
University of Granada (A.L.R.), a V Foundation/Applebeeâs Research Grant (D.S.W.) and
NCI R01 CA 109281 (D.S.W.).This is the final published version. It is also available from Nature Publishing at http://www.nature.com/ncomms/2014/140922/ncomms5998/full/ncomms5998.html
Halloween, Organization, and the Ethics of Uncanny Celebration
This article examines the relationship between organizational ethics, the uncanny, and the annual celebration of Halloween. We begin by exploring the traditional and contemporary organizational function of Halloween as âtension-management ritualâ (Etzioni, Sociol Theory 18(1):44â59, 2000) through which collective fears, anxieties, and fantasies are played out and given material expression. Combining the uncanny with the folkloric concept of ostension, we then examine an incident in which UK supermarket retailers made national news headlines for selling offensive Halloween costumes depicting âescaped mental patientsâ. Rather than treating this incident as a problem of moral hygieneâin which products are removed, apologies made, and lessons learnedâwe consider the value of Halloween as a unique and disruptive ethical encounter with the uncanny Other. Looking beyond its commercial appeal and controversy, we reflect on the creative, generous, and disruptive potential of Halloween as both tension-management ritual and unique organizational space of hospitality through which to receive and embrace alterity and so discover the homely within the unheimlich
Determinants of Cross-Border M&As and Shareholder Wealth Effects in a Globalized World
We analyze theoretical insights and empirical regularities related to factors determining the cross-border mergers and acquisitions (M&As) and impact of M&As on shareholder value of acquires and targets. The analysis of cross-border M&As is a relatively new subject and only recently received rigorous attention in academic research. Within this nascent literature, the survey pays particular attention to the emerging markets, which, in line with their growing role of in the global economy, became an increasingly important arena for cross-border M&As. The existing evidence point out to prevailing challenges in studying cross-border M&As by emerging markets firms. The results are often contradictory and tend to focus on a single country falling short of formally testing existing theories or developing comprehensive theories for emerging economies. We show that the type of factors increasing the value enhancing effects of M&As tends to be similar to the factors affecting the likelihood of M&As transactions. The remaining methodological challenges for the existing studies are related to strong evidence with respect to nonrandom selection of acquisition targets, which, among other âselection issues,â has important implications for choosing counterfactual evidence in order to appropriately compare pre- and postacquisition performance of firms
Enhanced killing of androgen-independent prostate cancer cells using inositol hexakisphosphate in combination with proteasome inhibitors
Effective treatments for androgen-independent prostate cancer (AIPCa) are lacking. To address this, emerging therapeutics such as proteasome inhibitors are currently undergoing clinical trials. Inositol hexakisphosphate (IP6) is an orally non-toxic phytochemical that exhibits antitumour activity against several types of cancer including PCa. We have previously shown that treatment of PC3 cells with IP6 induces the transcription of a subset of nuclear factor-ÎșB (NF-ÎșB)-responsive and pro-apoptotic BCL-2 family genes. In this study, we report that although NF-ÎșB subunits p50/p65 translocate to the nucleus of PC3 cells in response to IP6, inhibition of NF-ÎșB-mediated transcription using non-degradable inhibitor of ÎșB (IÎșB)-α does not modulate IP6 sensitivity. Treatment with IP6 also leads to increased protein levels of PUMA, BIK/NBK and NOXA between 4 and 8âh of treatment and decreased levels of MCL-1 and BCL-2 after 24âh. Although blocking transcription using actinomycin D does not modulate PC3 cell sensitivity to IP6, inhibition of protein translation using cycloheximide has a significant protective effect. In contrast, blocking proteasome-mediated protein degradation using MG-132 significantly enhances the ability of IP6 to reduce cellular metabolic activity in both PC3 and DU145 AIPCa cell lines. This effect of combined treatment on mitochondrial depolarisation is particularly striking and is also reproduced by another proteasome inhibitor (ALLN). The enhanced effect of combined MG132/IP6 treatment is almost completely inhibited by cycloheximide and correlates with changes in BCL-2 family protein levels. Altogether these results suggest a role for BCL-2 family proteins in mediating the combined effect of IP6 and proteasome inhibitors and warrant further pre-clinical studies for the treatment of AIPCa
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