367 research outputs found
The strong Atiyah conjecture for right-angled Artin and Coxeter groups
We prove the strong Atiyah conjecture for right-angled Artin groups and
right-angled Coxeter groups. More generally, we prove it for groups which are
certain finite extensions or elementary amenable extensions of such groups.Comment: Minor change
Building a Socio-technical Perspective of Community Resilience with a Semiotic Approach
Situated in the diversity and adversity of real-life contexts facing crisis situations, this research aims at boosting the resilience process within communities supported by digital and social technology. In this paper, eight community leaders in different parts of the world are invited to express their issues and wishes regarding the support of technology to face social challenges. Methods and artefacts based on the Organisational Semiotics (OS) and the Socially-Aware computing have been applied to analyse and consolidate this data. By providing both a systemic view of the problem and also leading to the identification of requirements, the analysis evidences some benefits of the OS-based approach to consolidate perspectives from different real-life scenarios towards building a socio-technical solution
QU Carinae: a SNeIa progenitor?
Optical spectra obtained in 2006-07 of the nova-like cataclysmic variable QU
Car are studied for radial velocities, line profiles, and line identifications.
We are not able to confirm the reported 10.9 hr orbital period from 1982,partly
because our sampling is not ideal for this purpose and also, we suspect,
because our radial velocities are distorted by line profile changes due to an
erratic wind. P-Cygni profiles are found in several of the emission lines,
including those of C IV. Carbon lines are abundant in the spectra, suggesting a
carbon enrichment in the doner star. The presence of [O III] 5007\AA and [N II]
6584\AA is likely due to a diffuse nebula in the vicinity of the system.
The wind signatures in the spectra and the presence of nebular lines are in
agreement with the accretion wind evolution scenario that has been suggested to
lead to SNeIa. We argue that QU Car is a member of the V Sge subclass of CVs,
and a possible SNeIa progenitor. It is shown that the recent light curve of QU
Car has ~1 mag low states, similar to the light curve of V Sge, strengthening
the connection of QU Car with V Sge stars, supersoft x-ray sources, and SNeIa
progenitors.Comment: Accepted in the Astronomical Journal. 11 pages, 3 tables, 5 figure
Linking Recent Discrimination-Related Experiences and Wellbeing via Social Cohesion and Resilience
The current study examined the relationship between recent experiences of discrimination and wellbeing and the mediating effects that social cohesion and resilience had on this relationship. Using online sampling, participants (N =255) from a South London community rated the levels of discrimination related experiences in the past 6 months, alongside measures of social cohesion, resilience, and wellbeing (happiness and depressive symptoms). Results revealed a negative relationship between recent experiences of discrimination and wellbeing which was explained by a serial mediation relationship between social cohesion and resilience, and singly by resilience alone. The study highlights how recent experiences of discrimination can lead to a depletion of personal resources and social resources (which in turn also lead to reduced personal resources) and in turn, to lower levels of wellbeing
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Linking recent discrimination-related experiences and wellbeing via social cohesion and resilience
United Kingdom The current study examined the relationship between recent experiences of discrimination and wellbeing and the mediating effects that social cohesion and resilience had on this relationship. Using online sampling, participants (N= 255) from a South London community rated the levels of discrimination related experiences in the past 6 months, alongside measures of social cohesion, resilience, and wellbeing (happiness and depressive symptoms). Results revealed a negative relationship between recent experiences of discrimination and wellbeing which was explained by a serial mediation relationship between social cohesion and resilience, and singly by resilience alone. The study highlights how recent experiences of discrimination can lead to a depletion of personal resources and social resources (which in turn also lead to reduced personal resources) and in turn, to lower levels of wellbeing
Dual EGFR inhibition in combination with anti-VEGF treatment: a phase I clinical trial in non-small cell lung cancer.
BackgroundPreclinical data indicate EGFR signals through both kinase-dependent and independent pathways and that combining a small-molecule EGFR inhibitor, EGFR antibody, and/or anti-angiogenic agent is synergistic in animal models.MethodsWe conducted a dose-escalation, phase I study combining erlotinib, cetuximab, and bevacizumab. The subset of patients with non-small cell lung cancer (NSCLC) was analyzed for safety and response.ResultsThirty-four patients with NSCLC (median four prior therapies) received treatment on a range of dose levels. The most common treatment-related grade ≥2 adverse events were rash (n=14, 41%), hypomagnesemia (n=9, 27%), and fatigue (n=5, 15%). Seven patients (21%) achieved stable disease (SD) ≥6 months, two achieved a partial response (PR) (6%), and two achieved an unconfirmed partial response (uPR) (6%) (total=32%). We observed SD≥6 months/PR/uPR in patients who had received prior erlotinib and/or bevacizumab, those with brain metastases, smokers, and patients treated at lower dose levels. Five of 16 patients (31%) with wild-type EGFR experienced SD≥6 months or uPR. Correlation between grade of rash and rate of SD≥6 months/PR was observed (p less than 0.01).ConclusionThe combination of erlotinib, cetuximab, and bevacizumab was well-tolerated and demonstrated antitumor activity in heavily pretreated patients with NSCLC
Orbital and stochastic far-UV variability in the nova-like system V3885 Sgr
Highly time-resolved time-tagged FUSE satellite spectroscopic data are
analysed to establish the far-ultraviolet (FUV) absorption line characteristics
of the nova-like cataclysmic variable binary, V3885 Sgr. We determine the
temporal behaviour of low (Ly_beta, CIII, NIII) and high (SIV, PV, OVI) ion
species, and highlight corresponding orbital phase modulated changes in these
lines. On average the absorption troughs are blueshifted due to a low velocity
disc wind outflow. Very rapid (~ 5 min) fluctuations in the absorption lines
are isolated, which are indicative of stochastic density changes. Doppler
tomograms of the FUV lines are calculated which provide evidence for structures
where a gas stream interacts with the accretion disc. We conclude that the line
depth and velocity changes as a function of orbital phase are consistent with
an asymmetry that has its origin in a line-emitting, localised disc-stream
interaction region.Comment: Accepted for publication in MNRA
QU Carinae: Supernova Ia in the making?
Variable NaI absorption lines have been reported in a number of type Ia
supernovae (SNeIa). The presence of this circumstellar material suggests that
cataclysmic variables (CVs) with a giant donor star may be the progenitors of
these SNeIa (Patat et al. 2007). We present echelle spectra of the CV QU
Carinae which strengthen the connection between CVs of the V Sge class, the
Accretion Wind Evolution scenario, variable wind features, variable NaI
absorption, and SNIa. This thread not only provides insight into the spectral
peculiarities of QU Car, but also links SNeIa as a class with their parent
systems.Comment: Accepted for publication to MNRAS. 23 pages (4 figures, 3 tables
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