1,583 research outputs found
Sir Francis Leicester's ‘Good Library’ at Nether Tabley
This article examines the book collection of Sir Francis Leicester (1674–1742) of Nether Tabley Hall, Cheshire. It charts the genesis of his collection; from an initial collection inherited from his grandfather Sir Peter Leicester to one directed by the interests of Sir Francis Leicester himself. The kind of collection Sir Francis assembled and whether it had a particular kind of identity is examined. The connections between this collection and those owned by other members of the late seventeenth- and early eighteenth-century elite are considered. Whether national and local scholars knew about his books and were granted access is explored. Evidence is provided for access having been granted by Sir Francis to non-elite readers from a variety of professional backgrounds. These potential readers are identified
Safety and Security at Special Events: The Case of the Salt Lake City Olympic Games
Special events offer the potential for considerable threats to public safety. Perhaps no other special event rivals the Olympic Games in scope, duration, and potential for threat to communities, participants, and dignitaries. This paper reports on the results of a study of safety and security at the Salt Lake Olympic Games by a team of researchers with wide-ranging access to operations, personnel and documents from the security effort at the 2002 Winter Games. This paper focuses on three specific areas: changing definitions of safety and security during the Games; the development and maintenance of organizational structures and interaction; and lessons learned for other large-scale events. The goal of this paper is to document some of the challenges of establishing a temporary security organization. The paper concludes that building such organizations require for their success a major focus on creating a set of shared assumptions and working relationships
The Theory of the Interleaving Distance on Multidimensional Persistence Modules
In 2009, Chazal et al. introduced -interleavings of persistence
modules. -interleavings induce a pseudometric on (isomorphism
classes of) persistence modules, the interleaving distance. The definitions of
-interleavings and generalize readily to multidimensional
persistence modules. In this paper, we develop the theory of multidimensional
interleavings, with a view towards applications to topological data analysis.
We present four main results. First, we show that on 1-D persistence modules,
is equal to the bottleneck distance . This result, which first
appeared in an earlier preprint of this paper, has since appeared in several
other places, and is now known as the isometry theorem. Second, we present a
characterization of the -interleaving relation on multidimensional
persistence modules. This expresses transparently the sense in which two
-interleaved modules are algebraically similar. Third, using this
characterization, we show that when we define our persistence modules over a
prime field, satisfies a universality property. This universality result
is the central result of the paper. It says that satisfies a stability
property generalizing one which is known to satisfy, and that in
addition, if is any other pseudometric on multidimensional persistence
modules satisfying the same stability property, then . We also show
that a variant of this universality result holds for , over arbitrary
fields. Finally, we show that restricts to a metric on isomorphism
classes of finitely presented multidimensional persistence modules.Comment: Major revision; exposition improved throughout. To appear in
Foundations of Computational Mathematics. 36 page
Quality Assurance of Spectral Ultraviolet Measurements in Europe Through the Development of a Transportable Unit (QASUME)
QASUME is a European Commission funded project that aims to develop and test a transportable unit for providing quality assurance to UV spectroradiometric measurements conducted in Europe. The comparisons will be performed at the home sites of the instruments, thus avoiding the risk of transporting instruments to participate in intercomparison campaigns. Spectral measurements obtained at each of the stations will be compared, following detailed and objective comparison protocols, against collocated measurements performed by a thoroughly tested and validated travelling unit. The transportable unit comprises a spectroradiometer, its calibrator with a set of calibration lamps traceable to the sources of different Standards Laboratories, and devices for determining the slit function and the angular response of the local spectroradiometers. The unit will be transported by road to about 25 UV stations over a period of about two years. The spectroradiometer of the transportable unit is compared in an intercomparison campaign with six instruments to establish a relation, which would then be used as a reference for its calibration over the period of its regular operation at the European stations. Different weather patterns (from clear skies to heavy rain) were present during the campaign, allowing the performance of the spectroradiometers to be evaluated under unfavourable conditions (as may be experienced at home sites) as well as the more desirable dry conditions. Measurements in the laboratory revealed that the calibration standards of the spectroradiometers differ by up to 10%. The evaluation is completed through comparisons with the same six instruments at their homes sites
ERβ Binds N-CoR in the Presence of Estrogens via an LXXLL-like Motif in the N-CoR C-terminus
Nuclear receptors (NRs) usually bind the corepressors N-CoR and SMRT in the absence of ligand or in the presence of antagonists. Agonist binding leads to corepressor release and recruitment of coactivators. Here, we report that estrogen receptor β (ERβ) binds N-CoR and SMRT in the presence of agonists, but not antagonists, in vitro and in vivo. This ligand preference differs from that of ERα interactions with corepressors, which are inhibited by estradiol, and resembles that of ERβ interactions with coactivators. ERβ /N-CoR interactions involve ERβ AF-2, which also mediates coactivator recognition. Moreover, ERβ recognizes a sequence (PLTIRML) in the N-CoR C-terminus that resembles coactivator LXXLL motifs. Inhibition of histone deacetylase activity specifically potentiates ERβ LBD activity, suggesting that corepressors restrict the activity of AF-2. We conclude that the ER isoforms show completely distinct modes of interaction with a physiologically important corepressor and discuss our results in terms of ER isoform specificity in vivo
A comparative study of arbitration algorithms for the Alpha 21364 pipelined router
Interconnection networks usually consist of a fabric of interconnected routers, which receive packets arriving at their input ports and forward them to appropriate output ports. Unfortunately, network packets moving through these routers are often delayed due to conflicting demand for resources, such as output ports or buffer space. Hence, routers typically employ arbiters that resolve conflicting resource demands to maximize the number of matches between packets waiting at input ports and free output ports. Efficient design and implementation of the algorithm running on these arbiters is critical to maximize network performance.This paper proposes a new arbitration algorithm called SPAA (Simple Pipelined Arbitration Algorithm), which is implemented in the Alpha 21364 processor's on-chip router pipeline. Simulation results show that SPAA significantly outperforms two earlier well-known arbitration algorithms: PIM (Parallel Iterative Matching) and WFA (Wave-Front Arbiter) implemented in the SGI Spider switch. SPAA outperforms PIM and WFA because SPAA exhibits matching capabilities similar to PIM and WFA under realistic conditions when many output ports are busy, incurs fewer clock cycles to perform the arbitration, and can be pipelined effectively. Additionally, we propose a new prioritization policy called the Rotary Rule, which prevents the network's adverse performance degradation from saturation at high network loads by prioritizing packets already in the network over new packets generated by caches or memory.Mukherjee, S.; Silla Jiménez, F.; Bannon, P.; Emer, J.; Lang, S.; Webb, D. (2002). A comparative study of arbitration algorithms for the Alpha 21364 pipelined router. ACM SIGPLAN Notices. 37(10):223-234. doi:10.1145/605432.605421S223234371
On the Clustering of Sub-millimeter Galaxies
We measure the angular two-point correlation function of sub-millimeter
galaxies (SMGs) from 1.1-millimeter imaging of the COSMOS field with the AzTEC
camera and ASTE 10-meter telescope. These data yields one of the largest
contiguous samples of SMGs to date, covering an area of 0.72 degrees^2 down to
a 1.26 mJy/beam (1-sigma) limit, including 189 (328) sources with S/N greater
than 3.5 (3). We can only set upper limits to the correlation length r_0,
modeling the correlation function as a power-law with pre-assigned slope.
Assuming existing redshift distributions, we derive 68.3% confidence level
upper limits of r_0 < 6-8 h^-1 Mpc at 3.7 mJy, and r_0 < 11-12 h^-1 Mpc at 4.2
mJy. Although consistent with most previous estimates, these upper limits imply
that the real r_0 is likely smaller. This casts doubts on the robustness of
claims that SMGs are characterized by significantly stronger spatial
clustering, (and thus larger mass), than differently selected galaxies at
high-redshift. Using Monte Carlo simulations we show that even strongly
clustered distributions of galaxies can appear unclustered when sampled with
limited sensitivity and coarse angular resolution common to current
sub-millimeter surveys. The simulations, however, also show that unclustered
distributions can appear strongly clustered under these circumstances. From the
simulations, we predict that at our survey depth, a mapped area of two
degrees^2 is needed to reconstruct the correlation function, assuming smaller
beam sizes of future surveys (e.g. the Large Millimeter Telescope's 6" beam
size). At present, robust measures of the clustering strength of bright SMGs
appear to be below the reach of most observations.Comment: 23 pages, 8 figures, accepted for publication in The Astrophysical
Journa
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