Comment on "The Jones-Hore theory of radical-ion-pair reactions is not self-consistent" (arXiv:1010.3888v3)

A short comment on "The Jones-Hore theory of radical-ion-pair reactions is not self-consistent" (arXiv:1010.3888v3) is presented. In the comment, it is pointed out that the paper includes a misconception about the Jones-Hore approach in Chem. Phys. Lett. 488 (2010) 90-93. The re-formulation is presented and it is demonstrated that the Jones-Hore theory is consistent at least on the point claimed by I. K. Kominis in the paper

Efficient Refocussing of One Spin and Two Spin Interactions for NMR Quantum Computation

The use of spin echoes to refocus one spin interactions (chemical shifts) and two spin interactions (spin-spin couplings) plays a central role in both conventional NMR experiments and NMR quantum computation. Here we describe schemes for efficient refocussing of such interactions in both fully and partially coupled spin systems.Comment: 4 pages, RevTeX, including 4 LaTeX figure

Implementation of a Deutsch-like quantum algorithm utilizing entanglement at the two-qubit level, on an NMR quantum information processor

We describe the experimental implementation of a recently proposed quantum algorithm involving quantum entanglement at the level of two qubits using NMR. The algorithm solves a generalisation of the Deutsch problem and distinguishes between even and odd functions using fewer function calls than is possible classically. The manipulation of entangled states of the two qubits is essential here, unlike the Deutsch-Jozsa algorithm and the Grover's search algorithm for two bits.Comment: 4 pages, two eps figure

The balance sheet of agriculture, 1957

Agriculture ; Agricultural productivity

Fast Quantum Search Algorithms in Protein Sequence Comparison - Quantum Biocomputing

Quantum search algorithms are considered in the context of protein sequence comparison in biocomputing. Given a sample protein sequence of length m (i.e m residues), the problem considered is to find an optimal match in a large database containing N residues. Initially, Grover's quantum search algorithm is applied to a simple illustrative case - namely where the database forms a complete set of states over the 2^m basis states of a m qubit register, and thus is known to contain the exact sequence of interest. This example demonstrates explicitly the typical O(sqrt{N}) speedup on the classical O(N) requirements. An algorithm is then presented for the (more realistic) case where the database may contain repeat sequences, and may not necessarily contain an exact match to the sample sequence. In terms of minimizing the Hamming distance between the sample sequence and the database subsequences the algorithm finds an optimal alignment, in O(sqrt{N}) steps, by employing an extension of Grover's algorithm, due to Boyer, Brassard, Hoyer and Tapp for the case when the number of matches is not a priori known.Comment: LaTeX, 5 page

NMR quantum computation with indirectly coupled gates

An NMR realization of a two-qubit quantum gate which processes quantum information indirectly via couplings to a spectator qubit is presented in the context of the Deutsch-Jozsa algorithm. This enables a successful comprehensive NMR implementation of the Deutsch-Jozsa algorithm for functions with three argument bits and demonstrates a technique essential for multi-qubit quantum computation.Comment: 9 pages, 2 figures. 10 additional figures illustrating output spectr

Predictive control design on an embedded robust output-feedback compensator for wind turbine blade-pitch preview control

The use of upstream wind measurements has motivated the development of blade-pitch preview controllers to improve rotor speed tracking and structural load reduction beyond that achievable via conventional feedback design. Such preview controllers, typically based upon model predictive control (MPC) for its constraint handling properties, alter the closed-loop dynamics of the existing blade-pitch feedback control system. This can result in the robustness properties of the original closed-loop system being no longer preserved. As a consequence, the aim of this work is to formulate an MPC layer on top of a given output-feedback controller, with a view to retaining the closed-loop robustness and frequency- domain performance of the latter. The separate nature of the proposed controller structure enables clear and transparent qualifications of the benefits gained by using preview and predictive control. This is illustrated by results obtained from closed-loop simulations upon a high-fidelity turbine, showing the performance comparison between a nominal feedback compensator and the proposed MPC-based preview controller

Analysis and design of tower motion estimator for wind turbines

The use of blade individual pitch control (IPC) provides a means of alleviating the harmful turbine loads that arise from the uneven and unsteady forcing from the oncoming wind. Such IPC algorithms, which mainly target the blade loads at specific frequencies, are designed to avoid excitations of other turbine dynamics such as the tower. Nonetheless, these blade and tower interactions can be exploited to estimate the tower movement from the blade load sensors. As a consequence, the aim of this paper is to analyse the observability properties of the blade and tower model and based on these insights, an estimator design is proposed to reconstruct the tower motion from the measurements of the flap-wise blade loads, that are typically available to the IPC. The proposed estimation strategy offers many immediate benefits, for example, the estimator obviates the need for hardware sensor redundancy, and the estimated signals can be used for control or fault monitoring purposes. We further show results obtained from high-fidelity turbine simulations to demonstrate the performance of the proposed estimator

Kako budući stručnjaci u sportu, tjelovježbi i tjelesnome odgoju percipiraju tjelesni izgled pretile djece

Anti-fat bias has been previously identified amongst practising obesity health care specialists, physical education (PE) teachers and students of exercise science and PE in samples in the USA and New Zealand. The present research investigated the perceptions of the physical self of ‘fat’ versus ‘normal-weight’ children held by 167 students studying sport exercise and PE related programmes in higher education in England. Onesample t-tests identified that the sample held negative perceptions towards ‘fat’ children (identified by subscale mean scores that were significantly different from the subscale mean of 2.5 that would identify equivocal perception between ‘fat’ and ‘normal-weight’ children) on five of the six subscales of an adapted version of the Children & Youth Physical Self Perception Profile (CONDITION 1.52±.49; BODY 1.63±.43; PHYSICAL SELF-WORTH 1.79±.47; SPORT 1.88±.45; GLOBAL SELF-ESTEEM 2.10±.50, all p<.01; STRENGTH 2.48±.52, p=.67). Such results are indicative of the obesity discourse that currently prevails within PE and sport professions; a discourse constructed, arguably, on misleading foundations. Obesity awareness training is, therefore, required in such trainee exercise science, sport and PE populations. Pedagogical approaches espoused during programmes of study ought to emphasize personal meaning, personal reference and childcenteredness so that such approaches are more likely to be employed in their future professional practice.Predrasude prema pretilim ljudima utvrđene su kod specijalista zdravstvene skrbi koji se bave pretilošću, kod profesora tjelesne i zdravstvene kulture te studenata kineziologije u SAD-u i Novom Zelandu. Cilj provedenog istraživanja bio je utvrditi percepcije tjelesnog izgleda “debele” u odnosu na djecu “normalne težine” kod 167 studenata kineziologije (sporta, vježbanja i fizičke kulture) u Engleskoj. Rezultati t-testova su pokazali da su ispitanici imali negativnu percepciju pretile djece (utvrđeno srednjim vrijednostima podljestvice koje su se statistički značajno razlikovale od njezine aritmetičke sredine (2,5) koja bi potvrdila jednaku percepciju pretile djece i djece normalne težine), na pet od ukupno šest podljestvica adaptirane verzije upitnika Children & Youth Physical Self Perception Profile (kondicijska pripremljenost 1.52±.49; slika tijela 1.63±.43; tjelesno samovrednovanje 1.79±.47; sportska kompetencija 1.88±.45; opće samopouzdanje 2.10±.50, svi na razini značajnosti p<.01; te tjelesna jakost i snaga 2.48±.52, p=.67). Dobiveni rezultati su indikativni za odnos prema pretilim osobama koji trenutno prevladava kod profesionalnih djelatnika u sportu i tjelesnoj i zdravstvenoj kulturi, a koji je nedvojbeno izgrađen na pogrešnim temeljima. Stoga je za populacije pripravnika u kineziologiji, sportu i tjelesnoj i zdravstvenoj kulturi potrebna edukacija i razvoj svijesti o pretilosti. Pedagoški pristupi koji se provode u okviru studijskih programa trebali bi naglasiti osobnost pojedinca, te osobni odnos i orijentaciju prema djetetu kako bi takvi pristupi i takav odnos prema djeci bili i primijenjeni u budućem profesionalnom radu sportskih stručnjaka i znanstvenika