16,996 research outputs found
A Berry-Esseen bound for M-estimators
No full textBentkus V, Bloznelis M, Götze F. A Berry-Esseen bound for M-estimators. SCANDINAVIAN JOURNAL OF STATISTICS. 1997;24(4):485-502.We prove a Berry-Esseen bound for general M-estimators under optimal regularity conditions on the scare function and the underlying distribution. As an application we obtain Berry-Esseen bounds for the sample median, the L-p-median, p > 1 and Huber's estimator of location
Polarization singularities in isotropic random vector waves
No full textFollowing Nye & Hajnal, we explore the geometry of complex vector waves by regarding them as a field of polarization ellipses. Singularities of this field are the C lines and L lines, where the polarization is purely circular and purely linear, respectively. The singularities can be reinterpreted as loci of photon spin 1 (C lines) and 0 (L lines). For Gaussian random superpositions of plane waves equidistributed in direction but with an arbitrary frequency spectrum, we calculate the density (length per unit volume) of C and L lines
Sex Addiction: the Chicken-and-Egg Dilemma of Diagnosis
No full textIn May 2013, the American Psychiatric Association will release the next version of the Diagnostic and Statistical Manual of Mental Disorders (DSM-V). Interestingly, sex addiction, despite significant attention from mainstream media, will be omitted from the manual. This omission presents a challenge to clinicians who treat sex addiction, and researchers aiming to further our understanding of the issue. This commentary outlines some of the reasons sex addiction was not included in the DSM-V, including a ‘chicken-and-egg’ conundrum, which makes it difficult to generate research without a clear diagnosis, and difficult to establish a definitive diagnosis without a supportive body of research
Black polarization sandwiches are square roots of zero
No full textIn the 2 x 2 matrices representing retarders and ideal polarizers, the eigenvectors are orthogonal. An example of the opposite case, where eigenvectors collapse onto one, is matrices M representing crystal plates sandwiched between a crossed polarizer and analyser. For these familiar combinations, M^2 = 0, so black sandwiches can be regarded as square roots of zero. Black sandwiches illustrate physics associated with degeneracies of non-Hermitian matrices
Knotted and linked phase singularities in monochromatic waves
No full textExact solutions of the Helmholtz equation are constructed, possessing wavefront dislocation lines (phase singularities) in the form of knots or links where the wave function vanishes ('knotted nothings'). The construction proceeds by making a nongeneric structure with a strength n dislocation loop threaded by a strength m dislocation line, and then perturbing this. In the resulting unfolded (stable) structure, the dislocation loop becomes an (m, n) torus knot if m and n are coprime, and N linked rings or knots if m and n have a common factor N; the loop or rings are threaded by an m-stranded helix. In our explicit implementation, the wave is a superposition of Bessel beams, accessible to experiment. Paraxially, the construction fails
Bertice Berry - 04/06/1999 - (Riall Lecture Series)
No full textBegun in 1988, the E. Pauline Riall Lecture Series brings to the University and community outstanding national lecturers in the field of education. The series was established by the late Miss Riall, long-time principal and teacher of the former Salisbury University's Campus School. A generous bequest was provided by Miss Riall's will to fund this special program.
Dr. Bertice Berry, Author, Sociologist, Comedian – 4/6/1999https://www.youtube.com/watch?v=VjageKPrvY
Quantum cores of optical phase singularities
No full textThe nodal line singularities (optical vortices) of classical scalar optics are smoothed in quantum optics, because of spontaneous emission into unoccupied modes. The radius of the 'quantum core' surrounding each classical singularity is proportional to ??. A trapped excited atom, steered into a nodal line of the classical field, is a possible detector for the effect. Analogous phenomena are anticipated for other waves, for example sound, where the silence at a nodal line is disturbed by pressure fluctuations of the fluid molecules
Topological events on wave dislocation lines: birth and death of small loops, and reconnection
No full textIn three-dimensional space, a wave dislocation, that is, a quantized (optical) vortex or phase singularity, is a line zero of a complex scalar wavefunction. As a 'time' parameter varies, the topology of the vortex can change by encounter with a line of vanishing vorticity (curl of the current associated with the wavefunction). An isolated critical point of the field intensity, sliding along the zero-vorticity line like a bead on a wire, meets the vortex as it encounters the line, and so participates in the singular event. Local expansio n and gauge and coordinates transformations show that the vortex topology can change generically by the appearance or disappearance of a loop, or by the reconnection of branches of a pair of hyperbolas
Phenolics in grape berry and key antioxidants
No full textPhenolic compounds are important components of die grape berry in the determination of wine style and quality. In the past decade, significant advances towards a better understanding of the genetics, biochemistry, and physiology governing the synthesis of this class of secondary metabolite have been made. This deeper knowledge of phenylpropanoid and flavonoid metabolism strengthens the foundation for practical applications in the vineyard; investigations involving cultural practices and manipulation of environmental effects can help viticulturists deliver grapes to winemakersthat are better suited to particular enological objectives, as well as possibly enriching the product in health-promoting compound
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