8,471 research outputs found
Varieties of Ontological Argument
I consider what I hope are increasingly sophisticated versions of ontological argument, beginning from simple definitional forms, through three versions to be found in Anselm, with their recent interpretations by Malcolm, Plantinga, Klima and Lowe. I try to show why none of these work by investigating both the different senses of necessary existence and the conditions under which logically necessary existence can be brought to bear. Although none of these arguments work, I think that they lead to interesting reflections on the nature of definition, on the conditions for possessing the property of necessary existence and point towards a different, neo-Platonic ground for God’s meeting the criteria for being logically necessary
A ’Trinitarian’ Theory of the Self
I argue that the self is simple metaphysically, whilst being complex psychologically and that the persona that links these moments might be dubbed ”creativity’ or ”imagination’. This theory is trinitarian because it ascribes to the self these three ”features’ or ”moments’ and they bear at least some analogy with the Persons of the Trinity, as understood within the neo- platonic, Augustinian tradition
Operator-Valued Frames for the Heisenberg Group
A classical result of Duffin and Schaeffer gives conditions under which a
discrete collection of characters on , restricted to , forms a Hilbert-space frame for . For the case of characters
with period one, this is just the Poisson Summation Formula. Duffin and
Schaeffer show that perturbations preserve the frame condition in this case.
This paper gives analogous results for the real Heisenberg group , where
frames are replaced by operator-valued frames. The Selberg Trace Formula is
used to show that perturbations of the orthogonal case continue to behave as
operator-valued frames. This technique enables the construction of
decompositions of elements of for suitable subsets of in
terms of representations of
Expression, Purification, Crystallization and Preliminary X-Ray Analysis of \u3cem\u3ePseudomonas aeuginosa\u3c/em\u3e AlgX
AlgX is a periplasmic protein required for the production of the exopolysaccharide alginate in Pseudomonas sp. and Azotobacter vinelandii. AlgX has been overexpressed and purified and diffraction-quality crystals have been grown using iterative seeding and the hanging-drop vapor-diffusion method. The crystals grew as flat plates with unit-cell parameters a=46.4, b=120.6, c=86.9Å, β=95.7°. The cyrstals exhibited the symmetry of space group P21 and diffracted to a minimimum d-spacing of 2.1Å. On the basis of the Matthews coefficient (VM=2.25Å3 Da-1), two molecules were estimated to be present in the asymmetric unit
Cellular expression and crystal structure of the murine cytomegalovirus MHC-Iv glycoprotein, m153
Mouse cytomegalovirus (MCMV), a β-herpesvirus that establishes latent and persistent infections in mice, is a valuable model for studying complex virus-host interactions. MCMV encodes the m145 family of putative immunoevasins with predicted MHC-I structure. Functions attributed to some family members include downregulation of host MHC-I (m152) and NKG2D ligands (m145, m152, m155) and interaction with inhibitory or activating NK receptors (m157). We present the cellular, biochemical and structural characterization of m153, which is a heavily glycosylated homodimer, that does not require β2m or peptide, and is expressed at the surface of MCMV-infected cells. Its 2.4 Å crystal structure confirms that this compact molecule preserves an MHC-I-like fold and reveals a novel mode of dimerization, confirmed by site-directed mutagenesis, and a distinctive disulfide-stabilized extended amino terminus. The structure provides a useful framework for comparative analysis of the divergent members of the m145 family
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Determination of the Quadrupole Coupling Constant in the N^{14} Atomic Ground State
The zero-field hyperfine frequencies in the ground state of atomic N14 have been measured in a hydrogen maser with sufficient accuracy to resolve the quadrupole coupling constant B. The result is B=+1.32±0.20 Hz.Molecular and Cellular Biolog
Ultraluminous infrared galaxies: mergers of sub-L* galaxies?
A sample of 27 low-redshift, mostly cool, ultraluminous infrared galaxies (ULIRGs) has been imaged at 1.6 μm with the Hubble Space Telescope (HST) Near-Infrared Camera and Multi-Object Spectrometer (NICMOS). The majority (67%) of the sample's galaxies are multiple-nucleus galaxies with projected separations of up to 17 kpc, and the rest of the sample (33%) are single-nucleus galaxies, as determined by the NICMOS angular resolution limit. The average observed, integrated (host+nucleus) H magnitude of our HST H sample ULIRGs is -24.3, slightly above that of an L* galaxy (MH = -24.2), and 52% of the sample's galaxies have sub-L* luminosities. The ULIRGs in the HST H sample are not generated as a result of the merging of two luminous (i.e., ≥L*) spiral galaxies. Instead, the interactions and mergers occur in general between two, or in some cases more, less massive sub-L* (0.3-0.5L*) galaxies.
Only one out of the 49 nuclei identified in the entire HST H sample has the properties of a bright quasar-like nucleus. On average, the brightest nuclei in the HST H sample galaxies (i.e., cool ULIRGs) are 1.2 mag fainter than warm ULIRGs and low-luminosity Bright Quasar Survey quasars (BQS QSOs) and 2.6 mag fainter than high-luminosity BQS QSOs. Since the progenitor galaxies involved in the merger are sub-L* galaxies, the mass of the central black hole in these ULIRGs would be only about (1-2) × 107 M☉, if the bulge-to-black hole mass ratio of nearby galaxies holds for ULIRGs. The estimated mass of the central black hole is similar to that of nearby Seyfert 2 galaxies but at least 1 order of magnitude lower than the massive black holes thought to be located at the center of high-luminosity QSOs. Massive nuclear starbursts with constant star formation rates of 10-40 M☉ yr-1 could contribute significantly to the nuclear H-band flux and are consistent with the observed nuclear H-band magnitudes of the ULIRGs in the HST H sample. An evolutionary merging scenario is proposed for the generation of the different types of ULIRGs and QSOs on the basis of the masses of the progenitors involved in the merging process. According to this scenario, cool ULIRGs would be the end product of the merging of two or more low-mass (0.3L*-0.5L*) disk galaxies. Warm ULIRGs and low-luminosity QSOs would be generated by a merger involving intermediate-mass (0.5 L*) disk galaxies. Under this scenario, warm ULIRGs could still be the dust-enshrouded phases of UV-bright low-luminosity QSOs, but cool ULIRGs, which are most ULIRGs, would not evolve into QSOs
A mathematical model for top-shelf vertigo: the role of sedimenting otoconia in BPPV
Benign Paroxysmal Positional Vertigo (BPPV) is a mechanical disorder of the
vestibular system in which calcite particles called otoconia interfere with the
mechanical functioning of the fluid-filled semicircular canals normally used to
sense rotation. Using hydrodynamic models, we examine the two mechanisms
proposed by the medical community for BPPV: cupulolithiasis, in which otoconia
attach directly to the cupula (a sensory membrane), and canalithiasis, in which
otoconia settle through the canals and exert a fluid pressure across the
cupula. We utilize known hydrodynamic calculations and make reasonable
geometric and physical approximations to derive an expression for the
transcupular pressure exerted by a settling solid particle in
canalithiasis. By tracking settling otoconia in a two-dimensional model
geometry, the cupular volume displacement and associated eye response
(nystagmus) can be calculated quantitatively. Several important features
emerge: 1) A pressure amplification occurs as otoconia enter a narrowing duct;
2) An average-sized otoconium requires approximately five seconds to settle
through the wide ampulla, where is not amplified, which suggests a
mechanism for the observed latency of BPPV; and 3) An average-sized otoconium
beginning below the center of the cupula can cause a volumetric cupular
displacement on the order of 30 pL, with nystagmus of order /s, which
is approximately the threshold for sensation. Larger cupular volume
displacement and nystagmus could result from larger and/or multiple otoconia.Comment: 15 pages, 5 Figures updated, to be published in J. Biomechanic
What Remains: Pseudotranslation as Salvage
Pseudotranslations are literary works which purport to be translations of lost or suppressed originals, i.e. to be ‘salvaged’ from oblivion or obscurity. Pseudotranslation has attracted a good deal of attention within translation studies in recent years, but as a practice it can be traced back a long way. This article discusses a number of examples of the type, from Cervantes’ Don Quixote and modern works treating Shakespeare as pseudotranslated (Star Trek VI, Tom Stoppard’s Arcadia) through notable eighteenth-century examples (Walpole’s The Castle of Otranto, MacPherson’s Ossian) to non-fictional fictions The Book of Mormon and ‘Nietzsche’s’ fraudulent late autobiography My Sister and I. Readers of translations usually trust that an original exists, and pseudotranslations abuse that trust. But even when an original does exist, translation performs a kind of salvage operation, acting as a kind of lifeboat which rescues a text from the passing of time and keeps it afloat for posterity
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