562 research outputs found
Faculty Development: Mission and Methods for Practical Integration
This essay proposes a Catholic structure for the intellectual life of faculty that invites participation in ways that honor their diverse backgrounds, even antipathy toward religion, while also demonstrating that identifiable Catholic perspectives, including Catholic social teaching, can provide a useful framework for faculty members to understand their academic roles in support of Catholic identity, no matter their religious background
Estimating Sales for Retail Centers: An Application of the Poisson Gravity Model
The projection of total retail sales for a shopping center development is of critical importance in its valuation, in the making of investment decisions by investors, and to the retail merchants who must make location decisions. In this study, we apply the Poisson Gravity Model to forecast the number of shopping trips attracted to each of the major retail centers in the Atlanta metropolitan area. In the second stage, the estimated total retail sales for all the shopping centers covered in the study, are allocated to the individual centers, based on their estimated shopping trip shares.
Salvageability of renal function following renal revascularisation in children with Takayasu’s arteritis-induced renal artery stenosis
Background. Renal artery revascularisation procedures are usually carried out on children with renal artery stenosis from varied causes, including Takayasu’s  arteritis. Reports on the outcome of such procedures in children usually refer to the improvement in blood pressure, with only minimal mention of effects on renal function.Objective. Salvageability renal function in children who underw ent renal revascularisation for Takayasu’s arteritis-induced renal artery stenosis (TARAS) was the focus of this study.Methods. We undertook a retrospective analysis of children aged ≤16 years with angiographically confirmed TARAS who underwent renal artery revascularisation procedures between 1990 and 2010. Outcomes of renal function were studied over a period of 2 years and were defined as: (i) improvement: >20% increase in estimated glomerular filtration rate (e-GFR) from presurgery value; (ii) stabilisation: e-GFR within 20% of presurgery value; and (iii) failure: >20% deterioration in e-GFR from presurgery value. The GFR was estimated using the Schwartz formula.Results. Twenty children (9 males and 11 females, age range 2 - 14 years) had 27 renal artery revascularisation procedures. Thirteen of the patients (65.0%) had bilateral renal artery stenosis. The baseline mean e-GFR was 88.6 (standard deviation (SD) 25.4) mL/min/1.73 m2 and the mean duration of follow-up was 28.80 (SD 25.62) months. All the patients had stable or improved renal function until the 2-year follow-up, when the proportion decreased to 92.3% (12/13), as failure was recorded in one child. Bilateral revascularisation was found to be significantly associated with improvement in renal function in the early postoperative period (p=0.04).Conclusion. Renal artery revascularisation procedures are successful in salvaging renal function in children with TARA
Photonic quantum signatures of chaos and boson sampling
Boson sampling is a paradigmatic example of a task that can be performed by a
quantum photonic computer yet is hard for digital classical computers. In a
typical boson sampling experiment, the scattering amplitude is determined by
the permanent of a submatrix of a unitary drawn from an ensemble of random
matrices. Random matrix theory plays a very important role in quite diverse
fields while at the same time being intimately related to quantum signatures of
chaos. Within this framework, a chaotic quantum system exhibits level
statistics characteristic of ensembles of random matrices. Such quantum
signatures are encoded in the unitary evolution and so in this work we combine
the dynamics of chaotic systems with boson sampling. One of the key results of
our work is that we demonstrate the intimate relation between out-of-time-order
correlators and boson sampling. We show that the unitary dynamics of a Floquet
system may be exploited to perform sampling tasks with identical particles
using single-mode phase shifters and multiport beamsplitters. At the end of our
paper propose a photonic implementation of the multiparticle kicked rotor,
which provides a concrete example of our general approach.Comment: 17 pages, 7 figures. Comments are welcom
Tertiary metamorphic core complexes in Sonora, northwestern Mexico
Several ranges encompassing more than 35,000 km^2 of Sonora, Mexico, contain distinctly lineated and foliated granitic and metamorphic rocks that constitute the lower plates of metamorphic core complexes. Penetrative deformation is characterized by gently dipping mylonitic foliation across which northeast trending stretching lineation is everywhere developed. Prominent northwest trending fractures, dikes, and normal faults are orthogonal to the lineation. Most kinematic indicators in lower plate mylonitic rocks record top-to-the-southwest sense of shear. Upper plate stratigraphic sequences include Mesozoic supracrustal rocks, Tertiary volcanic and sedimentary rocks, and allochthonous Precambrian basement. Tilted blocks of upper plate strata generally overlie the mylonites along gently dipping detachment faults. Previously published U-Pb and K-Ar ages from lower plate granitic orthogneisses, upper plate volcanic sequences, and crosscutting dikes constrain the time of mylonitic deformation and detachment faulting in several of these areas to late Oligocene-early Miocene. Partitioning of extensional strain in Sonora was influenced by pre-Tertiary crustal structure. The belt of core complexes developed across two contrasting blocks of continental crust separated by the N60 degrees W striking Mojave-Sonora megashear. Portions of the southern Papago block (northeast of the megashear) consisting of Jurassic magmatic are rocks and Upper Jurassic-Cretaceous siliciclastic and carbonate strata resting upon a concealed, tectonically fragmented Precambrian basement were especially susceptible to crustal attenuation. Some core complexes of the southern Papago block occur within zones trending northwest that may coincide with Late Jurassic lineaments. In the Caborca block (southwest of the megashear), core complex-related rocks and structures have not been identified where surface exposures of Middle Proterozoic basement and overlying Upper Proterozoic-Paleozoic platform strata are common. However, extensional mylonitic fabrics are locally developed along the margins of a Tertiary two-mica granite batholith. Core complexes on both sides of the megashear appear to be preferentially developed where Tertiary granites have intruded regions of crust with basement disrupted by pre-Tertiary structures. Sonoran core complexes preserve an extensional tectonic history comparable with that described from core complexes farther north in the United States and Canadian Cordillera. The timing of mid crustal extension in Sonora (25-18 Ma) is contemporaneous with the timing of core complex development in Arizona, Nevada, and Utah. Extension occurred later in these areas than in the Pacific Northwest-British Columbia region but earlier than in the Mojave Desert-Death Valley region. Middle Tertiary mylonitic fabrics of similar style and orientation have not been recognized farther south in Mexico. The southern terminus of the mid-Tertiary Cordilleran core complex belt appears to be in Sonora
Electron microscopy structure of human APC/C-CDH1-EMI1 reveals multimodal mechanism of E3 ligase shutdown.
The anaphase-promoting complex/cyclosome (APC/C) is a similar to 1.5-MDa multiprotein E3 ligase enzyme that regulates cell division by promoting timely ubiquitin-mediated proteolysis of key cell-cycle regulatory proteins. Inhibition of human APC/C-CDH1 during interphase by early mitotic inhibitor 1 (EMI1) is essential for accurate coordination of DNA synthesis and mitosis. Here, we report a hybrid structural approach involving NMR, electron microscopy and enzymology, which reveal that EMI1's 143-residue C-terminal domain inhibits multiple APC/C-CDH1 functions. The intrinsically disordered D-box, linker and tail elements, together with a structured zinc-binding domain, bind distinct regions of APC/C-CDH1 to synergistically both block the substrate-binding site and inhibit ubiquitin-chain elongation. The functional importance of intrinsic structural disorder is explained by enabling a small inhibitory domain to bind multiple sites to shut down various functions of a 'molecular machine' nearly 100 times its size
Multiple Weak Linear Motifs Enhance Recruitment and Processivity in SPOP-Mediated Substrate Ubiquitination
AbstractPrimary sequence motifs, with millimolar affinities for binding partners, are abundant in disordered protein regions. In multivalent interactions, such weak linear motifs can cooperate to recruit binding partners via avidity effects. If linear motifs recruit modifying enzymes, optimal placement of weak motifs may regulate access to modification sites. Weak motifs may thus exert physiological relevance stronger than that suggested by their affinities, but molecular mechanisms of their function are still poorly understood. Herein, we use the N-terminal disordered region of the Hedgehog transcriptional regulator Gli3 (Gli31-90) to determine the role of weak motifs encoded in its primary sequence for the recruitment of its ubiquitin ligase CRL3SPOP and the subsequent effect on ubiquitination efficiency. The substrate adaptor SPOP binds linear motifs through its MATH (meprin and TRAF homology) domain and forms higher-order oligomers through its oligomerization domains, rendering SPOP multivalent for its substrates. Gli3 has multiple weak SPOP binding motifs. We map three such motifs in Gli31-90, the weakest of which has a millimolar dissociation constant. Multivalency of ligase and substrate for each other facilitates enhanced ligase recruitment and stimulates Gli31-90 ubiquitination in in vitro ubiquitination assays. We speculate that the weak motifs enable processivity through avidity effects and by providing steric access to lysine residues that are otherwise not prioritized for polyubiquitination. Weak motifs may generally be employed in multivalent systems to act as gatekeepers regulating post-translational modification
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