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943 results on '"Helm J"'

2. Coherent Impurity Transport in an Attractive Binary Bose-Einstein condensate

Author

Edmonds, M. J., Helm, J. L., and Busch, Th.

Subjects
Condensed Matter - Quantum Gases
Abstract

We study the dynamics of a soliton-impurity system modeled in terms of a binary Bose-Einstein condensate. This is achieved by `switching off' one of the two self-interaction scattering lengths, giving a two component system where the second component is trapped entirely by the presence of the first component. It is shown that this system possesses rich dynamics, including the identification of unusual `weak' dimers that appear close to the zero inter-component scattering length. It is further found that this system supports quasi-stable trimers in regimes where the equivalent single-component gas does not, which is attributed to the presence of the impurity atoms which can dynamically tunnel between the solitons, and maintain the required phase differences that support the trimer state., Comment: 14 pages, 8 figures

Published
2018
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5. Non-integrable dynamics of matter-wave solitons in a density-dependent gauge theory

Author

Dingwall, R. J., Edmonds, M. J., Helm, J. L., Malomed, B. A., and Öhberg, P.

Subjects
Condensed Matter - Quantum Gases, Nonlinear Sciences - Pattern Formation and Solitons
Abstract

We study interactions between bright matter-wave solitons which acquire chiral transport dynamics due to an optically-induced density-dependent gauge potential. Through numerical simulations, we find that the collision dynamics feature several non-integrable phenomena, from inelastic collisions including population transfer and radiation losses to short-lived bound states and soliton fission. An effective quasi-particle model for the interaction between the solitons is derived by means of a variational approximation, which demonstrates that the inelastic nature of the collision arises from a coupling of the gauge field to velocities of the solitons. In addition, we derive a set of interaction potentials which show that the influence of the gauge field appears as a short-range potential, that can give rise to both attractive and repulsive interactions., Comment: Updated with minor corrections and additional references. To be published in New J. Phys

Published
2017
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6. Measuring the disorder of vortex lattices in a Bose-Einstein condensate

Author

Rakonjac, A., Marchant, A. L., Billam, T. P., Helm, J. L., Yu, M. M. H., Gardiner, S. A., and Cornish, S. L.

Subjects
Physics - Atomic Physics, Condensed Matter - Quantum Gases
Abstract

We report observations of the formation and subsequent decay of a vortex lattice in a Bose-Einstein condensate confined in a hybrid optical-magnetic trap. Vortices are induced by rotating the anharmonic magnetic potential that provides confinement in the horizontal plane. We present simple numerical techniques based on image analysis to detect vortices and analyze their distributions. We use these methods to quantify the amount of order present in the vortex distribution as it transitions from a disordered array to the energetically favorable ordered lattice., Comment: 8 pages, 10 figures

Published
2015
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7. Quantum reflection of bright solitary matter-waves from a narrow attractive potential

Author

Marchant, A. L., Billam, T. P., Yu, M. M. H., Rakonjac, A., Helm, J. L., Polo, J., Weiss, C., Gardiner, S. A., and Cornish, S. L.

Subjects
Physics - Atomic Physics, Condensed Matter - Quantum Gases, Quantum Physics
Abstract

We report the observation of quantum reflection from a narrow, attractive, potential using bright solitary matter-waves formed from a 85Rb Bose-Einstein condensate. We create narrow potentials using a tightly focused, red-detuned laser beam, and observe reflection of up to 25% of the atoms, along with the trapping of atoms at the position of the beam. We show that the observed reflected fraction is much larger than theoretical predictions for a narrow Gaussian potential well; a more detailed model of bright soliton propagation, accounting for the generic presence of small subsidiary intensity maxima in the red-detuned beam, suggests that these small intensity maxima are the cause of this enhanced reflection., Comment: 5 pages, 4 figures

Published
2015
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8. Sagnac Interferometry Using Bright Matter-Wave Solitons

Author

Helm, J. L., Cornish, S. L., and Gardiner, S. A.

Subjects
Condensed Matter - Quantum Gases, Physics - Atomic Physics
Abstract

We use an effective one-dimensional Gross-Pitaevskii equation to study bright matter-wave solitons held in a tightly confining toroidal trapping potential, in a rotating frame of reference, as they are split and recombined on narrow barrier potentials. In particular, we present an analytical and numerical analysis of the phase evolution of the solitons and delimit a velocity regime in which soliton Sagnac interferometry is possible, taking account of the effect of quantum uncertainty., Comment: 5 pages, 3 figures

Published
2014
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10. Splitting bright matter-wave solitons on narrow potential barriers: quantum to classical transition and applications to interferometry

Author

Helm, J. L., Rooney, S. J., Weiss, Christoph, and Gardiner, S. A.

Subjects
Condensed Matter - Quantum Gases
Abstract

We study bright solitons in the Gross-Pitaevskii equation as they are split and recombined in a low energy system. We present new analytic results determining the general region in which a soliton may not be split on a potential barrier, and confirm these results numerically. Furthermore, we analyse the energetic regimes where quantum fluctuations in the initial center of mass position and momentum become influential on the outcome of soliton splitting and recombination events. We then use the results of this analysis to determine a parameter regime where soliton interferometry is practicable., Comment: 15 pages, 11 figures

Published
2014
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17. Evaluating the Need for Preoperative MRI Before Primary Hip Arthroscopy in Patients 40 Years and Younger With Femoroacetabular Impingement Syndrome: A Multicenter Comparative Analysis

Author

Ramkumar, Prem N., primary, Berrier, Ava S., additional, Helm, J. Matthew, additional, Koolmees, Dylan S., additional, Pareek, Ayoosh, additional, Krych, Aaron J., additional, Makhni, Eric C., additional, Harris, Joshua D., additional, and Nwachukwu, Benedict U., additional

Published
2023
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20. Paper 45: Preoperative MRI Offers Minimal Clinical Utility, Delays Access to Hip Arthroscopy, and Lacks Cost-Effectiveness in Patients Aged 40 or Under with Classic Femoroacetabular Impingement Syndrome: A Retrospective 5-Year Analysis

Author

Helm, J. Matthew, primary, Berrier, Ava, additional, Vega, Jose, additional, Yalçin, Sercan, additional, Kunze, Kyle, additional, Harris, Joshua, additional, Feingold, Jake, additional, and Ramkumar, Prem, additional

Published
2022
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25. Advies over nut en noodzaak van een pollenmeetnetwerk

Author

Houweling, D, van der Helm, J, Versteeg-de Jong, A, Wesseling, J, Boomsma, C, and van Wijk, S

Subjects
RIVM rapport 2021-0221
Abstract

Stuifmeel (pollen) in de lucht kan hooikoorts veroorzaken. Ernstige klachten kunnen het leven van patiënten erg belemmeren. Twee pollenexperts hebben namens een groot aantal betrokken organisaties het ministerie van VWS gevraagd de voorlichting voor mensen met hooikoorts te verbeteren. Een onderdeel daarvan is een pollenmeetnetwerk. Het aantal en soort pollen in de lucht verschilt namelijk per plek en moment, per seizoen en per weerstype. Op dit moment tellen twee ziekenhuizen, in Leiden en Helmond, handmatig de pollen die de week ervoor in die omgeving in de lucht zaten. Het RIVM adviseert het ministerie van VWS om op deze twee locaties automatische pollentellers neer te zetten. Automatisch pollentellen is minder bewerkelijk en geeft meteen informatie over de pollen die er op dat moment zijn. Bij handmatige tellingen is deze informatie pas achteraf beschikbaar. Ook kunnen automatische tellingen beter voorspellen hoeveel van welke pollen er de komende dagen in de lucht zijn. Het RIVM adviseert ook de informatie voor hooikoortspatiënten te verbeteren. Zowel over de pollen zelf als over allergietesten, medicijnen en maatregelen om de klachten te verminderen. Met eenduidige informatie kunnen patiënten hun gedrag en medicijngebruik aanpassen aan de pollen in de lucht en zo mogelijk minder last van hooikoorts hebben. Verder adviseert het RIVM te verkennen hoeveel locaties met pollenmeetapparaten in Nederland minimaal nodig zijn voor een optimaal netwerk. Tot slot is het belangrijk in kaart te brengen hoeveel mensen ziek zijn of zich minder goed voelen door hooikoorts en wat dat de samenleving kost.

Published
2021

28. Triceps Tendon Rupture – A Novel Repair of an Uncommon Injury

Author

Homen, Dylan, Domingo-Johnson, E L, Helm, J Matthew, Schalow, Melinda, and Zumwalt, Mimi

Subjects
Triceps tendon, triceps rupture, Case Report, suture repair
Abstract

Introduction: Triceps tendon rupture is a rare injury accounting for

Published
2020

40. The PiGMaP consortium linkage map of the pig (Sus scrofa)

Author

Archibald, A. L., Haley, C. S., Brown, J. F., Couperwhite, S., McQueen, H. A., Nicholson, D., Coppieters, W., Van de Weghe, A., Stratil, A., Winterø, A. K., Fredholm, M., Larsen, N. J., Nielsen, V. H., Milan, D., Woloszyn, N., Robic, A., Dalens, M., Riquet, J., Gellin, J., Caritez, J. -C., Burgaud, G., Ollivier, L., Bidanel, J. -P., Vaiman, M., Renard, C., Geldermann, H., Davoli, R., Ruyter, D., Verstege, E. J. M., Groenen, M. A. M., Davies, W., Høyheim, B., Keiserud, A., Andersson, L., Ellegren, H., Johansson, M., Marklund, L., Miller, J. R., Anderson Dear, D. V., Signer, E., Jeffreys, A. J., Moran, C., Le Tissier, P., Muladno, Rothschild, M. F., Tuggle, C. K., Vaske, D., Helm, J., Liu, H. -C., Rahman, A., Yu, T. -P., Larson, R. G., and Schmitz, C. B.

Published
1995
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43. Effect of the estrogen receptor locus on reproduction and production traits in four commercial pig lines

Author

Short, T.H., Rothschild, M.F., Southwood, O.I., McLaren, D.G., Vries, A. de, Steen, S. van der, Eckardt, G.R., Tuggle, C.K., Helm, J., Vaske, D.A., Mileham, A.J., and Plastow, G.S.

Subjects
Estrogen -- Receptors, Swine -- Breeding, Zoology and wildlife conservation
Abstract

We investigated the effect of the estrogen receptor (ESR) gene on growth and reproductive traits in four Large White-based commercial pig lines. A total of 9,015 litter records from 4,262 sows genotyped at the ESR locus were analyzed to determine whether ESR influenced total number born (TNB) or number born alive (NBA). Teat number (TN), test ADG, ADFI, feed:gain ratio (F/G), and ultrasonic backfat (BF) were also analyzed to determine effects of ESR. The TNB and NBA were increased per favorable allele of ESR (P < .01) with additive effects of .42 (.31) and .39 (.31) pigs/litter in the first parity (later parities), respectively. Dominance effects were near zero in parity one, but they were .16 and .14 pigs for TNB and NBA, respectively, in later parities (P < .05). A favorable additive pleiotropic effect was detected for BF (P < .001; -.11 mm per copy of the favorable litter size allele). There were no detectable effects on ADG or F/G (P > .10), although ADF was reduced 18 g/d per copy of the favorable litter size allele (P < .05). Average TN was 13.1 for pigs carrying the favorable litter size allele vs 13.2 for noncarriers (P < .05). Marker-assisted selection using ESR is warranted to increase litter size in the Large White-based lines considered here and will be of considerable economic value to pork producers. Key Words: Estrogen Receptors, Reproduction, Growth, Genetic Markers, Major Genes, Pleiotropy

Published
1997

48. Irish society of Gastroenterology: Proceedings of summer meeting, boole auditorium, university college, cork on friday 27th and saturday 28th may, 1988.

Author

Murray, D. P., Foley, R., Whelton, M. J., Moriarty, K. J., Brooks, S., Loft, D., Mpoko, N., Gardner, V., Marsh, M. N., Stevens, Fiona M., Kearns, M., Moran, B., Sutton, G., Taylor, M., Karran, S. J., Courtney, M. G., O’Brien, M., McPartlin, J. M., Gibney, M. J., Scott, J. M., Weir, D. G., Suzuki, Y., Tobin, A., Quinn, D., Whelan, A., O’Morain, A., Waldron, R., O’Riordan, M., Kirwan, W. O., Ryan, T., Lennon, J., Crowe, J., Shinkwin, C., Kirwan, W., Mackle, E. J., Parks, T. G., O’Keefe, L., Lanigan, D., O’Donnell, M., Harte, P., O’Sullivan, G., Foley, D. P., Dunne, P., Dervan, P., Crowe, J. P., O’Callaghan, T., Chua, A., Kennedy, N. P., MacMathuna, P., Keating, J. J., Weir, D. G., Keeling, P. W. N., Leen, E., McKenna, D., Gilligan, D., Ward, R., Casey, E., Tobin, A., Hutchinson, L., Sweeney, E. C., O’Morain, C., Collins, J. S. A., Sloan, J. M., Watt, P. H., Hamilton, P. W., Love, A. H. G., Chua, A., Kennedy, N. P., MacMathuna, P., Keating, J. J., Maxwell, W. J., Brennan, D. P., Huang, J., McDonald, G., Weir, D. G., Keeling, P. W. N., Brennan, D. P., Kennedy, N. P., Keeling, P. W. N., McKenna, D., Ward, R., Gilligan, D., Tobin, A., Sweeney, E. C., O’Morain, C., Ryan, T., Lennon, J., Crowe, J., Diamond, T., Rowlands, B. J., Keating, J., O’Reilly, E., Burke, P., McDonald, G. S. A., Monson, J., Stephens, R., Corrigan, O., Keeling, P. W. N., Carey, P. D., Darzi, A., Monson, J. R. T., O’Morain, C., Tanner, W. A., Keane, F. B. V., Darzi, A., Monson, J. R. T., Carey, P. D., O’Morain, C., Tanner, W. A., Keane, F. B. V., Rogers, E., McAnena, O. J., Given, H. F., Keeling, P., O’Sullivan, G., DeMeester, T., Skinner, David B., Collins, J. K., O’Sullivan, G., O’Donoghue, M., O’Brien, F., O’Donovan, T., Corbett, A., Hahnvaganawong, C., Nolan, S., Collins, J., O’Sullivan, G., Murray, J., Hogan, B., Sullivan, M., Doyle, J. S., Butler, P., Walker, F., Murray, J., Doyle, J. S., O’Dwyer, P. J., Minton, J., Enright, H., Patchett, S., O’Connell, L., O’Donoghue, D. P., Afdhal, N. H., Collins, J. S. A., Cattey, R. P., Hogan, W. J., Helm, J. F., Ash, R., O’Briain, D. S., O’Malley, F., and Courtney, G.

Published
1991
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