81,540 research outputs found
Geometry of Multiplicative Preprojective Algebra
Crawley-Boevey and Shaw recently introduced a certain multiplicative analogue
of the deformed preprojective algebra, which they called the multiplicative
preprojective algebra. In this paper we study the moduli space of (semi)stable
representations of such an algebra (the multiplicative quiver variety), which
in fact has many similarities to the quiver variety. We show that there exists
a complex analytic isomorphism between the nilpotent subvariety of the quiver
variety and that of the multiplicative quiver variety (which can be extended to
a symplectomorphism between these tubular neighborhoods). We also show that
when the quiver is star-shaped, the multiplicative quiver variety parametrizes
Simpson's (poly)stable filtered local systems on a punctured Riemann sphere
with prescribed filtration type, weight and associated graded local system
around each puncture.Comment: 51pages; corrected typos and references; changed font; v4 is the same
as v3 except margi
Beyond Sufficiency: G.A. Cohen's Community Constraint on Luck Egalitarianism
G. A. Cohen conceptualizes socialism as luck egalitarianism constrained by a community principle. The latter mitigates certain inequalities to achieve a shared common life. This article explores the plausibility of the community constraint on inequality in light of two related problems. First, if it is voluntary, it fails as a response to âthe abandonment objectionâ to luck egalitarianism, as it would not guarantee imprudent people sufficient resources to avoid deprivation and to function as equal citizens in a democratic society. Contra Cohenite socialism, this appears unjust. Second, if it is instead enforced, coercive equalization beyond sufficiency-constrained luck egalitarianism, which is possibly necessary to achieve a shared common life, seems to require unjustified restrictions on liberty. I therefore argue that the constraint is most plausibly specified as requiring enforcement of sufficiency and only voluntary equalization thereafter. I also note, skeptically, why this constraint might be morally preferable to a purely sufficientarian alternative
Bounds for DNA codes with constant GC-content
We derive theoretical upper and lower bounds on the maximum size of DNA codes
of length n with constant GC-content w and minimum Hamming distance d, both
with and without the additional constraint that the minimum Hamming distance
between any codeword and the reverse-complement of any codeword be at least d.
We also explicitly construct codes that are larger than the best
previously-published codes for many choices of the parameters n, d and w.Comment: 13 pages, no figures; a few references added and typos correcte
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Organizing otherwise: translating anarchism in a voluntary sector organization
Although foundational texts in Critical Management Studies (CMS) pointed to the empirical significance of anarchism as an inspiration for alternative ways of organizing (Burrell, 1992), relatively little work of substance has been undertaken within CMS to explore how anarchists organize or how anarchist principles of organization might fare in other contexts. This paper addresses this gap by reporting on the experiences of a UK Voluntary Sector Organization (VSO) seeking to adopt non-hierarchical working practices inspired by anarchism. The paper analyses this process of organizational change by examining how ideas and practices are translated and transformed as they travel from one context (direct action anarchism) to another (the voluntary sector). Whilst the onset of austerity and funding cuts created the conditions of possibility for this change, it was the discursive translation of 'anarchism' into 'non-hierarchical organizing' that enabled these ideas to take hold. The concept of 'non-hierarchical' organization constituted an open space that was defined by negation and therefore capable of containing a multiplicity of meanings. Rather than having to explicitly embrace anarchism, members were able to find common ground on what they did not want (hierarchy) and create a discursive space for democratically determining what might replace it
Electronic gating circuit and ultraviolet laser excitation permit improved dosimeter sensitivity
Standard dosimeter reader, modified by adding an electronic gating circuit to trigger the intensity level photomultiplier, increases readout sensitivity of photoluminescent dosimeter systems. The gating circuit is controlled by a second photomultiplier which senses a short ultraviolet pulse from a laser used to excite the dosimeter
Vibrating diaphragm pressure transducer
Vibrating diaphragm transducer for pressure measurements in wind tunnels - construction, sensitivity, stability, energy losses, and cost estimat
Incarceration, Relationships, and Belonging: Insights into the Experiences of Two Male Youth Recently Released from Custody Facilities
This paper explores the family, school, and community experiences of two male youth who had recently been released from custody facilities and how these experiences contributed to their sense of belonging and self-esteem. Addressing the limited literature on self-esteem and belonging of young men who had been incarcerated, the exploratory study considers key themes of trust, family, friendships, and perceptions of belonging and self-esteem which emerge from interviews and guided journal writing sessions. A key finding is that alternative literacy programs, such as journal writing, provide mechanisms to engage young men in building their self-esteem and sense of belonging. The paper concludes with recommendations for teachers, community program facilitators, and social workers to support marginalized youth after having been released from incarceration as they re-enter family and community life
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