243 research outputs found
Protein threading by learning
No full textBy using techniques borrowed from statistical physics and neural networks, we determine the parameters, associated with a scoring function, that are chosen optimally to ensure complete success in threading tests in a training set of proteins. These parameters provide a quantitative measure of the propensities of amino acids to be buried or exposed and to be in a given secondary structure and are a good starting point for solving both the threading and design problems
The modernist angel: Art at the Limits of the Human in D. H. Lawrence, H. D. and Mina Loy
No full textPhDThe subject of this thesis is a figure that might provisionally be called the *modemist
angel'. Focusing on modernist literature, and more particularly on the work of D. H.
Lawrence, H. D. and Mina Loy, it aims to isolate from the many angels found in all periods
and all types of art a historically specific and intellectually coherent paradigm: an angel of
and for its modernist times. A figure of precisely this type could be said to exist in the
form of Walter Benjamin's 'angel of history'. Critics who address the question of the
modern angel in texts by Franz Kafka and Rainer Maria Rilke often do so in conjunction
with the problem posed by the angel of history. Beginning with a chapter on Benjamin,
this thesis nevertheless follows a different trajectory. Over five chapters, it explores a
modernist landscape formed not only by Lawrence, H. D. and Loy, but also by European
and American writers such as A. R. Orage, Allen Upward, Ezra Pound, Wallace Stevens,
Havelock Ellis, Edward Carpenter, Sigmund Freud and Friedrich Nietzsche. Although the
angel that emerges from this investigation might, in some respects, be said to anticipate
Benjamin's later version, this figure is also very different, standing for a project that is
distinctively, and recognisably, modernist in nature. He/she (the sex of the modernist
angel is often open to question) represents an attempt to reconcile the divine
responsibilities of the artist with the material and gendered conditions of being,
specifically of being human, in the modem world. This thesis looks again at the clash of
intellectual paradigms in the early-twentieth century - notably, the confrontation of the
Romantic view of art as a superhuman or sacred undertaking with the psychoanalytical or
evolutionary idea that all human endeavour is underpinned by sub-human motives - and
suggests the angel as a new and instructive figure through which to think the perilous
limits between the human and the divine in modernist literature
On zero-dimensionality of subgroups of locally compact groups
No full textsummary:Improving the recent result of the author we show that is equivalent to for every subgroup of a Hausdorff locally compact group
The Optical/UV Excess of X-Ray-dim Isolated Neutron Stars. I. Bremsstrahlung Emission from a Strangeon Star Atmosphere
No full textX-ray-dim isolated neutron stars (XDINSs) are characterized by Planckian spectra in X-ray bands, but show optical/ultraviolet (UV) excesses: the factors by which the measured photometry exceeds those extrapolated from X-ray spectra. To solve this problem, a radiative model of bremsstrahlung emission from a plasma atmosphere is established in the regime of a strangeon star. A strangeon star atmosphere could simply be regarded as the upper layer of a normal neutron star. This plasma atmosphere, formed and maintained by the interstellar-medium-accreted matter due to the so-called strangeness barrier, is supposed to be of two temperatures. All seven XDINS spectra could be well fitted by the radiative model, from optical/UV to X-ray bands. The fitted radiation radii of XDINSs are from 7 to 13 km, while the modeled electron temperatures are between 50 and 250 eV, except RX J0806.4-4123, with a radiation radius of similar to 3.5 km, indicating that this source could be a low-mass strangeon star candidate. This strangeon star model could further be tested by soft X-ray polarimetry, such as the Lightweight Asymmetry and Magnetism Probe, which is expected to be operational on China's space station around 2020.National Natural Science Foundation of China [11673002, U1531243, 11373011, U153120003]; Strategic Priority Research Program of CAS [XDB23010200]; Center for Astronomical Mega-Science, CASSCI(E)ARTICLE183
Spectral Analysis of a Dirac Operator with a Meromorphic Potential
No full textWe consider an operator Q(V) of Dirac type with a meromorphic potential given in terms of a function V of the form V(z) = λV1(z) + μV2(z), z ∈ C ＼ {0}, where V1 is a complex polynomial of 1/z, V2 is a polynomial of z, and λ and μ are non-zero complex parameters. The operator Q(V) acts in the Hilbert space L^2(IR^2;C^4) = ⊕^4L^2(IR^2). The main results we prove include: (i) the (essential) self-adjointness of Q(V); (ii) the pure discreteness of the spectrum of Q(V) ; (iii) if V1(z) = z^[-p] and 4 ≤ degV2 ≤ p + 2, then kerQ(V) ≠ {0} and dim kerQ(V) is independent of (λ, μ) and lower order terms of ∂V2/∂z; (iv) a trace formula for dim kerQ(V)
Lyapunov functions and global stability for SIR and SIRS epidemiological models with non-linear transmission
No full textLyapunov functions for 2-dim SIR and SIRS compartmental epidemic models with non-linear transmission rate of a very general form f(S, I) constrained by a few biologically feasible conditions are constructed. Global properties of these models including these with vertical and horizontal transmission, are thereby established. It is proved that, under the constant population size assumption, the concavity of the function f(S, I) with respect to the number of the infective hosts I ensures the uniqueness and the global stability of the positive endemic equilibrium state
Natural transformations of Weil functors into bundle functors
No full textsummary:[For the entire collection see Zbl 0699.00032.] \par Natural transformations of the Weil functor T\sp A of A-velocities [{\it I. Kola\v{r}}, Commentat. Math. Univ. Carol. 27, 723-729 (1986; Zbl 0603.58001)] into an arbitrary bundle functor F are characterized. In the case where F is a linear bundle functor, the author deduces that the dimension of the vector space of all natural transformations of T\sp A into F is finite and is less than or equal to \dim (F\sb 0{\mathcal{R}}\sp k). The spaces of all natural transformations of Weil functors into linear functors of higher order tangent bundles are determined
The prevalence of substance use amongst first and fourth year commerce students at the University of Cape Town : a comparative analysis
No full textIncludes bibliographical references
Dimension of boolean valued lattices and rings
No full textAbstractA. Joyal initiated the dimension theory of rings in a topos. Joyal's notion of Krull dimension of lattices and rings was considered by the author, who has shown that dim K[X] = 1 for any field K in a topos I. The basic aim of this paper is to prove that dim R[X] = 1 for any regular ring R in I, that is by working in commutative algebra without choice and excluded middle. Given a regular ring R, let E be the boolean algebra of idempotents of R, and E = sh(E) the topos of sheaves over E with the finite cover topology. The Pierce representation R̃ of R is a field in E, so that dim R̃[X] = 1 and this implies dim R[X] = 1 by using preserving properties of the global sections functor Γ: E → I. Section 1 deals with lattices in the topos E = sh(E) of sheaves over a boolean algebra E with the finite cover topology. We characterize lattices in E as lattice homomorphisms E → D, and we consider the dimension of lattices in this form. In Section 2 we describe rings in E as boolean homomorphisms E → E(A). Here, we discuss the Pierce representation and polynomials. The spectrum of a ring is considered in Section 3, which ends with the aim theorem
Technology education in secondary schools
No full textThe author outlines his background and refers to current relevant attitudes. He considers changes which have influenced the curriculum for manufacturing in resilient materials in schools. The word technology is currently in common use. Having examined a range of sources for common themes, the author synthesises a definition and examines some implications. He uses the example of the development of the electronic computer to illustrate the difference between science and technology before arguing that 'new technology', in schools, properly belongs within the framework of 'Craft Design & Technology' (CDT). Using references from industry, education and elsewhere, he describes the process of designing and upholds its predominance as a skill to be fostered. Arising from its cyclic nature are implications for the assessment of performance. As labour saving devices, windmills and robots are widely separated by time but both require control and the author seeks to explore this link. The components of control are also identifiable in the work of pupils over many years. He contrasts industrial robots with those of their prophets. The need far a review of the education service was established in 1976. The consequent chain of political initiatives in Britain is described highlighting the nature of politics. He considers a case history when those who 'do' become championed by those who would have it done’. Durham Local Education Authority's progress in CDT in-service training is described and the world of 'lower school' technology is explored by considering both pupil and updated teacher. The author describes industrial reality and intimates a curriculum possibility - the design, by lower school pupils, of automatic systems. He sees the computer in the CDT curriculum both as design tool and as part of solutions to human needs
- …
