44,430,829 research outputs found

    Dilution of seawater affects the Ca2 + transport in the outer mantle epithelium of crassostrea gigas

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    Varying salinities of coastal waters are likely to affect the physiology and ion transport capabilities of calcifying marine organisms such as bivalves. To investigate the physiological effect of decreased environmental salinity in bivalves, adult oysters (Crassostrea gigas) were exposed for 14 days to 50% seawater (14) and the effects on mantle ion transport, electrophysiology and the expression of Ca2+ transporters and channels relative to animals maintained in full strength sea water (28) was evaluated. Exposure of oysters to a salinity of 14 decreased the active mantle transepithelial ion transport and specifically affected Ca2+ transfer. Gene expression of the Na+/K+-ATPase and the sarco(endo)plasmic reticulum Ca2+-ATPase was decreased whereas the expression of the T-type voltage-gated Ca channel and the Na+/Ca2+-exchanger increased compared to animals maintained in full SW. The results indicate that decreased environmental salinities will most likely affect not only osmoregulation but also bivalve biomineralization and shell formation.Funding Agency European Union (EU) 605051 Swedish Mariculture Research Center, SWEMARC, University of Gothenburg Herbert & Karin Jacobssons Stiftelse 15/h17 Helge Ax:son Johnsons Stiftelse F18-0128 Portuguese Foundation for Science and Technology UID/Multi/04326/2019 Portuguese Foundation for Science and Technology UID/Multi/04326/2019 FCT, under the "Norma Transitoria" DL57/2016/CP1361/CT0020 DL57/2016/CP1361/CT0011info:eu-repo/semantics/publishedVersio

    Motor control retraining exercises for shoulder impingement: effects on function, muscle activation, and biomechanics in young adults

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    Objective: Evidence for effective management of shoulder impingement is limited. The present study aimed to quantify the clinical, neurophysiological, and biomechanical effects of a scapular motor control retraining for young individuals with shoulder impingement signs.Method: Sixteen adults with shoulder impingement signs (mean age 22 ? 1.6 years) underwent the intervention and 16 healthy participants (24.8 ? 3.1years) provided reference data. Shoulder function and pain were assessed using the Shoulder Pain and Disability Index (SPADI) and other questionnaires. Electromyography (EMG) and 3 dimensional motion analysis was used to record muscle activation and kinematic data during arm elevation to 90? and lowering in 3 planes. Patients were assessed pre and post a 10-week motor control based intervention, utilizing scapular orientation retraining.Results: Pre-intervention, patients reported pain and reduced function compared to the healthy participants (SPADI in patients 20 ? 9.2; healthy 0 ? 0). Post intervention, the SPADI scores reduced significantly (P < .001) by a mean of 10 points (?4). EMG showed delayed onset and early termination of serratus anterior and lower trapezius muscle activity pre-intervention, which improved significantly post-intervention (P < .05). Pre intervention, patients exhibited on average 4.6-7.4? less posterior tilt, which was significantly lower in 2 arm elevation planes (P < .05) than healthy participants. Postintervention, upward rotation and posterior tilt increased significantly (P <.05) during 2 arm movements, approaching the healthy values.Conclusion: A 10-week motor control intervention for shoulder impingement increased function and reduced pain. Recovery mechanisms were indicated by changes in muscle recruitment andscapular kinematics. The efficacy of the intervention requires further examined in a randomizedcontrol trial

    On Approximating the Number of kk-cliques in Sublinear Time

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    We study the problem of approximating the number of kk-cliques in a graph when given query access to the graph. We consider the standard query model for general graphs via (1) degree queries, (2) neighbor queries and (3) pair queries. Let nn denote the number of vertices in the graph, mm the number of edges, and CkC_k the number of kk-cliques. We design an algorithm that outputs a (1+ε)(1+\varepsilon)-approximation (with high probability) for CkC_k, whose expected query complexity and running time are O\left(\frac{n}{C_k^{1/k}}+\frac{m^{k/2}}{C_k}\right)\poly(\log n,1/\varepsilon,k). Hence, the complexity of the algorithm is sublinear in the size of the graph for Ck=ω(mk/21)C_k = \omega(m^{k/2-1}). Furthermore, we prove a lower bound showing that the query complexity of our algorithm is essentially optimal (up to the dependence on logn\log n, 1/ε1/\varepsilon and kk). The previous results in this vein are by Feige (SICOMP 06) and by Goldreich and Ron (RSA 08) for edge counting (k=2k=2) and by Eden et al. (FOCS 2015) for triangle counting (k=3k=3). Our result matches the complexities of these results. The previous result by Eden et al. hinges on a certain amortization technique that works only for triangle counting, and does not generalize for larger cliques. We obtain a general algorithm that works for any k3k\geq 3 by designing a procedure that samples each kk-clique incident to a given set SS of vertices with approximately equal probability. The primary difficulty is in finding cliques incident to purely high-degree vertices, since random sampling within neighbors has a low success probability. This is achieved by an algorithm that samples uniform random high degree vertices and a careful tradeoff between estimating cliques incident purely to high-degree vertices and those that include a low-degree vertex

    Quantum singular value transformation and beyond: exponential improvements for quantum matrix arithmetics

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    Quantum computing is powerful because unitary operators describing the time-evolution of a quantum system have exponential size in terms of the number of qubits present in the system. We develop a new "Singular value transformation" algorithm capable of harnessing this exponential advantage, that can apply polynomial transformations to the singular values of a block of a unitary, generalizing the optimal Hamiltonian simulation results of Low and Chuang. The proposed quantum circuits have a very simple structure, often give rise to optimal algorithms and have appealing constant factors, while usually only use a constant number of ancilla qubits. We show that singular value transformation leads to novel algorithms. We give an efficient solution to a certain "non-commutative" measurement problem and propose a new method for singular value estimation. We also show how to exponentially improve the complexity of implementing fractional queries to unitaries with a gapped spectrum. Finally, as a quantum machine learning application we show how to efficiently implement principal component regression. "Singular value transformation" is conceptually simple and efficient, and leads to a unified framework of quantum algorithms incorporating a variety of quantum speed-ups. We illustrate this by showing how it generalizes a number of prominent quantum algorithms, including: optimal Hamiltonian simulation, implementing the Moore-Penrose pseudoinverse with exponential precision, fixed-point amplitude amplification, robust oblivious amplitude amplification, fast QMA amplification, fast quantum OR lemma, certain quantum walk results and several quantum machine learning algorithms. In order to exploit the strengths of the presented method it is useful to know its limitations too, therefore we also prove a lower bound on the efficiency of singular value transformation, which often gives optimal bounds.Comment: 67 pages, 1 figur

    Characterization of water and wildlife strains as a subgroup of Campylobacter jejuni using DNA microarrays.

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    Campylobacter jejuni is the leading cause of human bacterial gastroenteritis worldwide, but source attribution of the organism is difficult. Previously, DNA microarrays were used to investigate isolate source, which suggested a non-livestock source of infection. In this study we analysed the genome content of 162 clinical, livestock and water and wildlife (WW) associated isolates combined with the previous study. Isolates were grouped by genotypes into nine clusters (C1 to C9). Multilocus sequence typing (MLST) data demonstrated that livestock associated clonal complexes dominated clusters C1-C6. The majority of WW isolates were present in the C9 cluster. Analysis of previously reported genomic variable regions demonstrated that these regions were linked to specific clusters. Two novel variable regions were identified. A six gene multiplex PCR (mPCR) assay, designed to effectively differentiated strains into clusters, was validated with 30 isolates. A further five WW isolates were tested by mPCR and were assigned to the C7-C9 group of clusters. The predictive mPCR test could be used to indicate if a clinical case has come from domesticated or WW sources. Our findings provide further evidence that WW C. jejuni subtypes show niche adaptation and may be important in causing human infection

    Electronic, vibrational and magnetic properties of a novel C_{48}N_{12} aza-fullerene

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    We study the structural, electronic, vibrational and magnetic properties of a novel C48N12{\rm C}_{48}{\rm N}_{12} aza-fullerene using density functional theory and restricted Hartree-Fock theory. Optimized geometries and total energy of this fullerene have been calculated. We find that for C48N12{\rm C}_{48}{\rm N}_{12} the total ground state energy is about -67617 eV, the HOMO-LUMO gap is about 1.9 eV, five strong IR spectral lines are located at the vibrational frequencies, 461.5 cm1{\rm cm}^{-1}, 568.4 cm1{\rm cm}^{-1}, 579.3 cm1{\rm cm}^{-1}, 1236.1 cm1{\rm cm}^{-1}, 1338.9 cm1{\rm cm}^{-1}, the Raman scattering activities and depolarization ratios are zero, and 10 NMR spectral signals are predicted. Calculations of diamagnetic shielding factor, static dipole polarizabilities and hyperpolarizabilities of C48N12{\rm C}_{48}{\rm N}_{12} are performed and discussed.Comment: published in Chem.Phys.Let

    Discovering the roots: Uniform closure results for algebraic classes under factoring

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    Newton iteration (NI) is an almost 350 years old recursive formula that approximates a simple root of a polynomial quite rapidly. We generalize it to a matrix recurrence (allRootsNI) that approximates all the roots simultaneously. In this form, the process yields a better circuit complexity in the case when the number of roots rr is small but the multiplicities are exponentially large. Our method sets up a linear system in rr unknowns and iteratively builds the roots as formal power series. For an algebraic circuit f(x1,,xn)f(x_1,\ldots,x_n) of size ss we prove that each factor has size at most a polynomial in: ss and the degree of the squarefree part of ff. Consequently, if f1f_1 is a 2Ω(n)2^{\Omega(n)}-hard polynomial then any nonzero multiple ifiei\prod_{i} f_i^{e_i} is equally hard for arbitrary positive eie_i's, assuming that ideg(fi)\sum_i \text{deg}(f_i) is at most 2O(n)2^{O(n)}. It is an old open question whether the class of poly(nn)-sized formulas (resp. algebraic branching programs) is closed under factoring. We show that given a polynomial ff of degree nO(1)n^{O(1)} and formula (resp. ABP) size nO(logn)n^{O(\log n)} we can find a similar size formula (resp. ABP) factor in randomized poly(nlognn^{\log n})-time. Consequently, if determinant requires nΩ(logn)n^{\Omega(\log n)} size formula, then the same can be said about any of its nonzero multiples. As part of our proofs, we identify a new property of multivariate polynomial factorization. We show that under a random linear transformation τ\tau, f(τx)f(\tau\overline{x}) completely factors via power series roots. Moreover, the factorization adapts well to circuit complexity analysis. This with allRootsNI are the techniques that help us make progress towards the old open problems, supplementing the large body of classical results and concepts in algebraic circuit factorization (eg. Zassenhaus, J.NT 1969, Kaltofen, STOC 1985-7 \& Burgisser, FOCS 2001).Comment: 33 Pages, No figure

    Perfil de autocuidado do doente em tratamentos com hemodiálise: estudo descritivo transversal

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    This study aimed to explore the self-care theory proposed by Orem and to perform a detailed categorization of the related profiles. The performed research enabled the identification of four profiles and goals were set to establish a correlation between self-care profiles and self-management of the therapeutic regimen; to establish a relationship between demographic characteristics and selfcare profiles and to establish a correlation between self-care profiles and obstacles to an effective management of the therapeutic regimen. The design was cross-sectional, descriptive and correlational. Interviews were conducted with 122 patients undergoing haemodialysis in a healthcare unit. Clinical outcomes were extracted from medical recordsThe results show that patients with the highest scores in the responsible self-care profile are those with improved knowledge (liquid - R=.250; p=.006; medication – R=.246; p=.006); who take better care of their vascular access (R=.186; p=.042); who manage their diet better (R=.247; p=.006); and who face fewer obstacles than the others (R=-.207; p=.022). The research findings show that the implementation of successful nursing treatment plans depends on the knowledge and understanding of patients perceptions regarding self-care and that this indicator will be of the utmost importance when helping patients in the transition to a new health condition and to experience a better quality of life.Estudo explóratorio transversal, descritivo e correlacional sobre a teoria do autocuidado proposta por Orem. A pesquisa realizada permitiu a identificação de quatro dimensões: definição dos perfis para estabelecer a correlação entre o autocuidado e o autogestão do regime terapêutico; estudo da relação entre as características demográficas e autocuidado; estudar a correlação entre os perfis de autocuidado e os obstáculos ao regime terapêutico. Entrevistas realizadas a 122 doentes em hemodiálise numa unidade de saúde. Os resultados clínicos foram extraídos a partir dos registos e mostram que os doentes com os maiores scores no perfil autocuidado responsável são aqueles com melhor conhecimento (liquid. - R = 0,250; p = 0,006; medicação - R = 0,246; p = 0,006); quem cuida melhor de acesso vascular (R = 0,186; p = 0,042); quem melhor administra a dieta (R = 0,267; p = 0,006); e quem enfrenta menos obstáculos (R = 0,207; p = 0,022). Os resultados da pesquisa mostram que a implementação de planos de tratamento depende do conhecimento e compreensão dos doentes sobre o autocuidado e que este indicador é de maior importância na ajuda do doente na transição para uma nova condição de saúde e melhor qualidade de vidainfo:eu-repo/semantics/publishedVersio
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