151 research outputs found
Reconstruction of Objects by Direct Demodulation
High resolution reconstruction of complicated objects from incomplete and
noisy data can be achieved by solving modulation equations iteratively under
physical constraints. This direct demodulation method is a powerful technique
for dealing with inverse problem in general case. Spectral and image
restorations and computerized tomography are only particular cases of general
demodulation. It is possible to reconstruct an object in higher dimensional
space from observations by a simple lower dimensional instrument through direct
demodulation. Our simulations show that wide field and high resolution images
of space hard X-rays and soft gamma rays can be obtained by a collimated
non-position-sensitive detector without coded aperture masks.Comment: 11 pages, 6 figure
Wild birds respond to flockmate loss by increasing their social network associations to others
Understanding the consequences of losing individuals from wild populations is a current and pressing issue, yet how such loss influences the social behaviour of the remaining animals is largely unexplored. Through combining the automated tracking of winter flocks of over 500 wild great tits (Parus major) with removal experiments, we assessed how individualsâ social network positions responded to the loss of their social associates. We found that the extent of flockmate loss that individuals experienced correlated positively with subsequent increases in the number of their social associations, the average strength of their bonds and their overall connectedness within the social network (defined as summed edge weights). Increased social connectivity was not driven by general disturbance or changes in foraging behaviour, but by modifications to fine-scale social network connections in response to losing their associates. Therefore, the reduction in social connectedness expected by individual loss may be mitigated by increases in social associations between remaining individuals. Given that these findings demonstrate rapid adjustment of social network associations in response to the loss of previous social ties, future research should examine the generality of the compensatory adjustment of social relations in ways that maintain the structure of social organizationThe work was funded by an NERC studentship and EGI
Research Fellowship to J.A.F. and grants from the ERC and BBSRC
(AdG 250164; BB/L006081/1) to B.C.S
A discursive approach to narrative accounts of hearing voices and recovery
Substantive objective: To research the range of discursive constructions ârecoveredâ voice hearers employ to describe hearing voices and the implications for positioning and subjectivity (what can be thought and felt) using each construction.
Methodological objective and method: To explore a âsympatheticâ application of Foucauldian discourse analysis, adapting Willigâs (2008 Willig, C. 2008. Introducing Qualitative Research in Psychology, Maidenhead: Open University Press. ) method, analysing two published accounts.
Results and conclusions: Heterogeneous discursive constructions for talking about hearing voices were identified, including: âmany-âselvesââ, âtaking-the-lead-in-your-own-recoveryâ, âvoices-as-an-âimagined-worldââ and âvoices-as-a-coping-strategy-for-dealing-with-traumaâ. The discourse of the biomedical model was not prominent, suggesting alternate discursive constructions may create subjects with a greater capacity for âliving with voicesâ and create a subjectivity from which vantage point the experience holds meaning and value and can be integrated into life experiences. This research may have useful clinical applications for mental health services aiming to collaboratively explore service usersâ ways of understanding hearing voices
Gravitational Lensing at Millimeter Wavelengths
With today's millimeter and submillimeter instruments observers use
gravitational lensing mostly as a tool to boost the sensitivity when observing
distant objects. This is evident through the dominance of gravitationally
lensed objects among those detected in CO rotational lines at z>1. It is also
evident in the use of lensing magnification by galaxy clusters in order to
reach faint submm/mm continuum sources. There are, however, a few cases where
millimeter lines have been directly involved in understanding lensing
configurations. Future mm/submm instruments, such as the ALMA interferometer,
will have both the sensitivity and the angular resolution to allow detailed
observations of gravitational lenses. The almost constant sensitivity to dust
emission over the redshift range z=1-10 means that the likelihood for strong
lensing of dust continuum sources is much higher than for optically selected
sources. A large number of new strong lenses are therefore likely to be
discovered with ALMA, allowing a direct assessment of cosmological parameters
through lens statistics. Combined with an angular resolution <0.1", ALMA will
also be efficient for probing the gravitational potential of galaxy clusters,
where we will be able to study both the sources and the lenses themselves, free
of obscuration and extinction corrections, derive rotation curves for the
lenses, their orientation and, thus, greatly constrain lens models.Comment: 69 pages, Review on quasar lensing. Part of a LNP Topical Volume on
"Dark matter and gravitational lensing", eds. F. Courbin, D. Minniti. To be
published by Springer-Verlag 2002. Paper with full resolution figures can be
found at ftp://oden.oso.chalmers.se/pub/tommy/mmviews.ps.g
Voiceless but empowered farmers in corporate supply chains: contradictory imagery and instrumental approach to empowerment
There have been calls for a shift of focus towards the political and power-laden aspects of transitioning towards socially equitable global supply chains. This paper offers an empirically grounded response to these calls from a critical realist stance in the context of global food supply chains. We examine how an imaginary for sustainable farming structured around an instrumental construction of empowerment limits what is viewed as permissible, desirable and possible in global food supply chains. We adopt a multimodal Critical Discourse Analysis (CDA) to examine the sustainable farming imaginary for smallholder farmers constructed by one large organization, Unilever, in a series of videos produced and disseminated on YouTube. We expose the underlying mechanisms of power and marginalization at work within the sustainability imaginary and show how âempowermentâ has the potential to create of new dependencies for these farmers. We recontextualize the representations to show that while the imaginary may be commercially feasible, it is less achievable in terms of empowering smallholder farmers
The fulfillment of parties' election pledges : a comparative study on the impact of power sharing
Why are some parties more likely than others to keep the promises they made during previous election campaigns? This study provides the first comparative analysis that addresses this question with common definitions of pledges and fulfillment. We study the fulfillment of 18,743 pledges made in 54 election campaigns in 12 countries. We find high levels of pledge fulfillment for most parties that enter the government executive, and substantially lower levels for parties that do not. The findings challenge the common view of parties as promise breakers. The degree to which governing parties share power affects pledge fulfillment, with parties in single-party executives, both with and without legislative majorities, having the highest fulfillment rates. Within coalition governments, the likelihood of pledge fulfillment depends on whether the party receives the chief executive post and whether another governing party made a similar pledge, but not on the ideological range of the coalition
Functional mechanisms underlying pleiotropic risk alleles at the 19p13.1 breast-ovarian cancer susceptibility locus
A locus at 19p13 is associated with breast cancer (BC) and ovarian cancer (OC) risk. Here we analyse 438 SNPs in this region in 46,451 BC and 15,438 OC cases, 15,252 BRCA1 mutation carriers and 73,444 controls and identify 13 candidate causal SNPs associated with serous OC (P=9.2 Ă 10-20), ER-negative BC (P=1.1 Ă 10-13), BRCA1-associated BC (P=7.7 Ă 10-16) and triple negative BC (P-diff=2 Ă 10-5). Genotype-gene expression associations are identified for candidate target genes ANKLE1 (P=2 Ă 10-3) and ABHD8 (P<2 Ă 10-3). Chromosome conformation capture identifies interactions between four candidate SNPs and ABHD8, and luciferase assays indicate six risk alleles increased transactivation of the ADHD8 promoter. Targeted deletion of a region containing risk SNP rs56069439 in a putative enhancer induces ANKLE1 downregulation; and mRNA stability assays indicate functional effects for an ANKLE1 3âČ-UTR SNP. Altogether, these data suggest that multiple SNPs at 19p13 regulate ABHD8 and perhaps ANKLE1 expression, and indicate common mechanisms underlying breast and ovarian cancer risk
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