420 results on '"Stewart GR"'
Search Results
2. Highly prevalent geriatric medications and their effect on β-amyloid fibril formation
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Zakia Zaman, Radia Islam, Bhavya Koganti, Vaibhavkumar Falki, Tammy Osentoski, Stewart Graham, and Md. Golam Sharoar
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Alzheimer’s disease ,β-amyoid ,Cytotoxicity ,Gariatric medication ,Mild cognitive impairment ,Neurology. Diseases of the nervous system ,RC346-429 - Abstract
Abstract Background The unprecedented increase in the older population and ever-increasing incidence of dementia are leading to a “silver tsunami” in upcoming decades. To combat multimorbidity and maintain daily activities, elderly people face a high prevalence of polypharmacy. However, how these medications affect dementia-related pathology, such as Alzheimer’s β-amyloid (Aβ) fibrils formation, remains unknown. In the present study, we aimed to analyze the medication profiles of Alzheimer’s disease (AD; n = 124), mild cognitive impairment (MCI; n = 114), and non-demented (ND; n = 228) patients to identify highly prevalent drugs and to determine the effects of those drugs on Aβ fibrils formation. Methods Study subjects (≥ 65 years) were recruited from an academic geriatric practice that heavily focuses on memory disorders. The disease state was defined based on the score of multiple cognitive assessments. Individual medications for each subject were listed and categorized into 10 major drug classes. Statistical analysis was performed to determine the frequency of individual and collective drug classes, which are expressed as percentages of the respective cohorts. 10 µM monomeric β-amyloid (Aβ) 42 and fibrillar Aβ (fAβ) were incubated for 6–48 h in the presence of 25 µM drugs. fAβ was prepared with a 1:10 ratio of Aβ42 to Aβ40. The amount of Aβ fibrils was monitored using a thioflavin T (Th-T) assay. Neuronal cells (N2A and SHSY-5Y) were treated with 25 µM drugs, and cell death was measured using a lactose dehydrogenase (LDH) assay. Results We noticed a high prevalence (82–90%) of polypharmacy and diverse medication profiles including anti-inflammatory (65–77%), vitamin and mineral (64–72%), anti-cholesterol (33–41%), anti-hypersensitive (35–39%), proton pump inhibitor (23–34%), anti-thyroid (9–21%), anti-diabetic (5–13%), anti-constipation (9–11%), anti-coagulant (10–13%), and anti-insomnia (9–20%) drugs in the three cohorts. Our LDH assay with 18 highly prevalent drug components showed toxic effects of Norvasc, Tylenol, Colace, and Plavix on N2A cells, and of vitamin D and Novasc on SH-SY5Y cells. All these drugs except Colace significantly reduced the amount of Aβ fibril when incubated with Aβ42 for a short period (6 h). However, Lipitor, vitamin D, Levothyroxine, Prilosec, Flomax, and Norvasc prominently reduce the amount of fibrils when incubated with monomeric Aβ42 for a longer period (48 h). Furthermore, our disaggregation study with fAβ showed consistent results for cholecalciferol (vitamin D), omeprazole (Prilosec), clopidogrel hydrogensulfate (Flomax), levothyroxine, and amlodipine (Norvasc). The chemical structures of these four efficient molecules contain polyphenol components, a characteristic feature of the structures of polyphenolic inhibitors of Aβ fibrillation. Conclusion A higher polypharmacy incidence was observed in an elderly population of 228 ND, 114 MCI, and 124 AD patients. We found that several highly recommended drug components, including vitamin D3, Levothyroxine, Prilosec, Flomax, and Norvasc, efficiently reduce the amount of fibrils formed by monomeric Aβ42 and existing preformed Aβ fibrils in vitro. However, only Levothyroxine was able to prevent Aβ-mediated toxicity to SH-SY5Y cells. Our study suggested that these drugs likely function as polyphenolic inhibitors of Aβ.
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- 2024
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3. Low-temperature anomalies in the high-field specific heat of UCd11
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Andraka, B, Stewart, GR, and Fisk, Z
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Physical Sciences ,Chemical Sciences ,Engineering ,Fluids & Plasmas - Abstract
The specific heat of UCd11 has been investigated in magnetic fields up to 16 T and in the temperature range 0.3510 K. In addition to the well-known 5-K magnetic transition, another anomaly is observed below 2 K in fields larger than 10 T. This anomaly can be related to the previously reported signature in the temperature-dependent resistivity under pressure. Furthermore, the magnetic fields do not affect the high-temperature specific heat (above the 5-K transition). The latter observation is discussed in relation to the origin of the extremely large electronic effective mass of UCd11. © 1991 The American Physical Society.
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- 1991
4. CeCu4Al and CeCu2Zn2Al: Very-heavy-fermion systems in high magnetic fields
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Andraka, B, Kim, JS, Stewart, GR, and Fisk, Z
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Physical Sciences ,Chemical Sciences ,Engineering ,Fluids & Plasmas - Abstract
CeCu4Al and CeCu2Zn2Al are heavy-fermion systems with extremely enhanced C/T (the specific heat divided by temperature) values of 2.3 and 1.8 J/K2, respectively, as T>0 K. The field dependence of the low-temperature specific heat is also extreme: At 11 T, C of CeCu4Al is reduced by more than a factor of 5 and at 12.5 T, C of CeCu2Zn2Al is suppressed by a factor of about 7. Magnetic-field-caused changes of the specific heat of CeCu4Al are consistent with a single-ion Kondo model. Magnetic correlations are at least partially responsible for the enhanced low-temperature specific heat of CeCu2Zn2Al. © 1991 The American Physical Society.
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- 1991
5. Infrared properties of T’-phase R2CuO4 insulating compounds
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Herr, SL, Kamarás, K, Tanner, DB, Cheong, S-W, Stewart, GR, and Fisk, Z
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Physical Sciences ,Chemical Sciences ,Engineering ,Fluids & Plasmas - Abstract
Reflectance studies on single crystals of a series of rare-earth (R=Pr, Nd, Sm, Gd) copper oxides have been made to determine phonon frequencies as a function of rare-earth mass. The increase in interatomic force constants with increasing rare-earth mass, which leads to a reduction in the lattice parameters, increases the vibrational frequencies. In addition, the change from the T-phase La2CuO4 to the T
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- 1991
6. The 2021 Room-Temperature Superconductivity Roadmap
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Lilia, Boeri, Hennig, Richard, Hirschfeld, Peter, Profeta, Gianni, Sanna, Antonio, Zurek, Eva, Pickett, Warren E, Amsler, Maximilian, Dias, Ranga, Eremets, Mikhail I, Heil, Christoph, Hemley, Russell J, Liu, Hanyu, Ma, Yanming, Pierleoni, Carlo, Kolmogorov, Aleksey N, Rybin, Nikita, Novoselov, Dmitry, Anisimov, Vladimir, Oganov, Artem R, Pickard, Chris J, Bi, Tiange, Arita, Ryotaro, Errea, Ion, Pellegrini, Camilla, Requist, Ryan, Gross, EKU, Margine, Elena Roxana, Xie, Stephen R, Quan, Yundi, Hire, Ajinkya, Fanfarillo, Laura, Stewart, GR, Hamlin, JJ, Stanev, Valentin, Gonnelli, Renato S, Piatti, Erik, Romanin, Davide, Daghero, Dario, Valenti, Roser, Boeri, Lilia [0000-0003-1186-2207], Profeta, Gianni [0000-0002-0535-7573], Sanna, Antonio [0000-0001-6114-9552], Zurek, Eva [0000-0003-0738-867X], Pickett, Warren E [0000-0003-4591-7691], Heil, Christoph [0000-0001-9693-9183], Liu, Hanyu [0000-0003-2394-5421], Pierleoni, Carlo [0000-0001-9188-3846], Novoselov, Dmitry [0000-0003-1668-3734], Pickard, Christopher [0000-0002-9684-5432], Arita, Ryotaro [0000-0001-5725-072X], Errea, Ion [0000-0002-5719-6580], Pellegrini, Camilla [0000-0003-2614-1111], Requist, Ryan [0000-0001-6887-3463], Stewart, Gregory R [0000-0001-7251-1684], Gonnelli, Renato S [0000-0001-7108-8458], Piatti, Erik [0000-0001-8733-5230], Apollo - University of Cambridge Repository, European Commission, Lilia, Boeri [0000-0003-1186-2207], Hennig, Richard [0000-0003-4933-7686], Hirschfeld, Peter [0000-0003-0375-7386], Amsler, Maximilian [0000-0001-8350-2476], Dias, Ranga [0000-0002-0830-4928], Eremets, Mikhail I [0000-0001-9861-3152], Hemley, Russell J [0000-0001-7398-8521], Ma, Yanming [0000-0003-3711-0011], Kolmogorov, Aleksey N [0000-0002-0669-7756], Rybin, Nikita [0000-0001-7053-5295], Anisimov, Vladimir [0000-0002-3683-861X], Oganov, Artem R [0000-0001-7082-9728], Pickard, Chris J [0000-0002-9684-5432], Bi, Tiange [0000-0001-5866-190X], Gross, EKU [0000-0002-0113-759X], Margine, Elena Roxana [0000-0002-5573-9940], Xie, Stephen R [0000-0001-8415-4514], Quan, Yundi [0000-0002-6359-9749], Hire, Ajinkya [0000-0003-3147-2521], Fanfarillo, Laura [0000-0002-6452-8520], Stewart, GR [0000-0001-7251-1684], Hamlin, JJ [0000-0002-8685-153X], Stanev, Valentin [0000-0001-6129-133X], Romanin, Davide [0000-0003-1094-5369], Daghero, Dario [0000-0003-2180-7682], and Valenti, Roser [0000-0003-0497-1165]
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Engineering ,CLIMATE CHANGE ,SOLID STATE CHEMISTRY ,ELECTRON-PHONON INTERACTIONS ,RESEARCH EFFORTS ,HYDRIDES ,MACROSCOPIC QUANTUM ,crystal structure prediction ,CRYSTAL STRUCTURE ,novel superconductors ,superconductor ,electron–phonon interaction ,SUPERCONDUCTOR ,NOVEL SUPERCONDUCTOR ,General Materials Science ,Topical Review ,SOLID-STATE PHYSICS ,NOVEL SUPERCONDUCTORS ,ROADMAP ,Superconductivity ,AMBIENT CONDITIONS ,Room-temperature superconductor ,ELECTRON-PHONON INTERACTION ,business.industry ,SUPERCONDUCTIVITY ,superconductivity ,Sulfur hydride ,hydrides ,Metallic hydrogen ,Condensed Matter Physics ,Engineering physics ,CRYSTAL STRUCTURE PREDICTION ,electron-phonon interaction ,TEMPERATURE SUPERCONDUCTORS ,electron���phonon interaction ,QUANTUM THEORY ,business - Abstract
Designing materials with advanced functionalities is the main focus of contemporary solid-state physics and chemistry. Research efforts worldwide are funneled into a few high-end goals, one of the oldest, and most fascinating of which is the search for an ambient temperature superconductor (A-SC). The reason is clear: superconductivity at ambient conditions implies being able to handle, measure and access a single, coherent, macroscopic quantum mechanical state without the limitations associated with cryogenics and pressurization. This would not only open exciting avenues for fundamental research, but also pave the road for a wide range of technological applications, affecting strategic areas such as energy conservation and climate change. In this roadmap we have collected contributions from many of the main actors working on superconductivity, and asked them to share their personal viewpoint on the field. The hope is that this article will serve not only as an instantaneous picture of the status of research, but also as a true roadmap defining the main long-term theoretical and experimental challenges that lie ahead. Interestingly, although the current research in superconductor design is dominated by conventional (phonon-mediated) superconductors, there seems to be a widespread consensus that achieving A-SC may require different pairing mechanisms. In memoriam, to Neil Ashcroft, who inspired us all. © 2022 The Author(s). Published by IOP Publishing Ltd. Yundi Quan has provided many useful discussions on this topic, and assistance with preparation of the figures in this paper. Giustino’s review [12] contains a wealth of references on this topic. This work was supported by US National Science Foundation Grant DMR 1607139. 3. We acknowledge Ashkan Salamat, Elliot Snider, Nathan Dasenbrock-Gammon, Raymond McBride, Mathew Debessai for useful discussions. This was supported by NSF, Grant No. DMR-1809649, and by the DOE Stockpile Stewardship Academic Alliance Program, Grant No. DE-NA0003898.5. CH acknowledges support from the Austrian Science Fund (FWF) Project No. P 32144-N36. 6. This work was supported principally by the US National Science Foundation (DMR-1933622), and by the US Department of Energy (DE-SC0020340 and DE-NA0003975). 7. I would like to thank all my collaborators and friends that contributed to this work: D M Ceperley, M Holzmann, V Gorelov, G Rillo, Y Yubo, M A Morales. This work was supported by ANR-France under the program ‘Accueil de Chercheurs de Haut Niveau 2015’ project: HyLightExtreme. 8. MA acknowledges support from the Swiss National Science Foundation (Project P4P4P2-180669). 9. This work was supported by the National Natural Science Foundation of China (Grant Nos. 52090024 and 12074138), the Science Challenge Project (Grant No. TZ2016001), the Fundamental Research Funds for the Central Universities (Jilin University, JLU), the Program for JLU Science and Technology Innovative Research Team (JLUSTIRT), and the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDB33000000) 10. ANK acknowledges the support through the NSF Award No. DMR-1821815. 11. We thank the Russian Science Foundation (Grant 19-72-30043) for support. 12. I thank Alice Shipley and Michael Hutcheon for their careful reading of the manuscript and insightful comments. This work has been funded by the EPSRC over many years (Projects EP/G007489/1 and EP/P022596/1), and through a Royal Society Wolfson Research Merit Award. 13. We acknowledge the National Science Foundation (DMR-1827815) for financial support. 14. The author acknowledges the financial support by JSPS KAK-ENHI Grant No. 19H05825. 15. This research was supported by the European Research Council (ERC) under the European Union’s Horizon 2020 Research and Innovation Program (Grant Agreement No. 802533). 16. We acknowledge financial support by the European Research Council Advanced Grant FACT (ERC-2017-AdG-788890). AS acknowledges hospitality of the Physics Department of La Sapienza, under the program ‘Professori Visitatori 2020’. 17. ERM acknowledges support from the National Science Foundation (Award No. OAC-1740263). 18. The work was supported by the US Department of Energy Basic Energy Sciences under Contract No. DE-SC-0020385. 19. We thank G Profeta and G Lamura for fruitful scientific discussions. We acknowledge funding from the MIUR PRIN-2017 program (Grant No. 2017Z8TS5B—‘Tuning and understanding Quantum phases in 2D materials—Quantum2D’). 20. We thank G Profeta and G Lamura for fruitful scientific discussions. We acknowledge funding from the MIUR PRIN-2017program (Grant No. 2017Z8TS5B—‘Tuning and understanding Quantum phases in 2D materials—Quantum2D’). 21. We acknowledge financial support by the Deutsche Forschungs-Gemeinschaft through Grant (DFG) for funding through TRR 288–422213477 (B05). This research was supported in part by the National Science Foundation under Grant No. NSF PHY-1748958.
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- 2021
7. Enhancement of Superconductivity through Lattice Softening
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Matthias, BT, Stewart, GR, Giorgi, AL, Smith, JL, Fisk, Z, and Barz, H
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General Science & Technology - Abstract
The superconducting transition temperature of an iridium-yttrium eutectic is enhanced extraordinarily through lattice softening. This is shown by a drastically reduced Debye temperature.
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- 1980
8. Consistence of spin fluctuations and superconductivity in UPt3
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Stewart, GR, Fisk, Z, Willis, JO, and Smith, JL
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Fluid capacity measurements on the heavy formion superconductor UPt3 in an 11T magnetic field show that aboveapproximately 7 K, UPt3 behaves like the spin fluctuation compounds UAl2 and TiB2. Magnetoresistance measurements on UPt3 at 1.2 K also yield results similar to UAl2 in contrast to the other heavy fermion superconductors CeCu3Si3 and UBe1, which show a magneticresistance effect of opposite sign. Thus, experimental results permit continued speculation of triplet superconductivity in UPt3. © 1984 Elsevier Science Publishers B.V.
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- 1984
9. Strong depression of magnetism in heavy fermion U2Zn17
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Willis, JO, Fisk, Z, Stewart, GR, and Ott, HR
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Depression ,Mental Health ,Condensed Matter Physics ,Materials Engineering ,Mechanical Engineering ,Applied Physics - Abstract
We have investigated the effects of impurities on the heavy fermion system U2Zn17. The Neél temperature of 9.7 K in pure U2Zn17 is strongly depressed to below 1.5 K with 2% Cu (on the Zn site) or 20% Th (on the U site). The electronic specific heat coefficient is practically independent of impurity concentration above any magnetic ordering temperature. © 1986.
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- 1986
10. Upper critical magnetic field of the heavy-fermion superconductor UPt3
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Chen, JW, Lambert, SE, Maple, MB, Fisk, Z, Smith, JL, Stewart, GR, and Willis, JO
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Physical Sciences ,Chemical Sciences ,Engineering ,Fluids & Plasmas - Abstract
The longitudinal and transverse upper critical magnetic fields Hc2 and Hc2 as a function of temperature T of a single-crystal specimen of the heavy-fermion superconductor UPt3 were measured resistively with the current flowing along the hexagonal c axis. The slope of the linear part of the Hc2 (T) curve near the superconducting transition temperature Tc=0.52 K equals 63 kOe/K, from which a zero-temperature superconducting coherence length 3/401/4120 can be inferred. An analysis using previously reported specific-heat data yields an effective mass ~200 times the free-electron mass and a value of 3/401/4170. The electrical resistivity between Tc and 8 K varies as Tn with n=1.6±0.1. © 1984 The American Physical Society.
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- 1984
11. Variation of the heavy fermion ground state in CeCu2Si2 crystals by stoichiometry control
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Batlogg, B, Remeika, JP, Cooper, AS, Stewart, GR, Fisk, Z, and Willis, JO
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Physical Sciences ,Condensed Matter Physics ,Materials Engineering ,Mechanical Engineering ,Applied Physics ,Materials engineering ,Condensed matter physics - Abstract
To gain into the formation of the heavy Fermion state in CeCu2Si2 we have studied the relationship between the high temperature and low temperature physical properties. The single crystals are grown from metallic solvents, such as Sn, In or Ga. The low temperature susceptibility χ can be varied by factors of 5, and samples with smallest χ have the largest linear contribution γ to the specific heat. This "anticorrelation" of χ and γ is unexpected. The reduction of χ at low T is mainly due to a temperature independent antiferromagnetic molecular-field type interaction χ-1(T)=χ-10(T)+λ, and not due to interactions which become dominant below a characteristic temperature. Superconductivity occurs in small χ - large γ samples. © 1985.
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- 1985
12. High field specific heat of single crystal UPt3
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Stewart, GR, Fisk, Z, Smith, JL, Franse, JJM, Menovsky, A, and Brandt, BL
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Condensed Matter Physics ,Materials Engineering ,Mechanical Engineering ,Applied Physics - Abstract
Low temperature specific heat data of aligned single crystals of UPt3, RRR = 140, with high magnetic field applied either along the c-axis or perpendicular to the c-axis are reported. No evidence for a metamagnetic transition as observed previously in susceptibility and resistivity measurements is seen, with no change for H in the c-direction and large ( ≈ 20%), temperature-dependent changes observed for H perpendicular to c. Magnetoresistivity measurements on one of the single crystals indicate that the transition in resistivity occurs at a lower field in our sample than observed in the sample reported on previously (18 vs. 20 T). © 1988.
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- 1988
13. New Ce Heavy-Fermion System: CeCu6
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Stewart, GR, Fisk, Z, and Wire, MS
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Physical Sciences ,Chemical Sciences ,Engineering ,Fluids & Plasmas - Abstract
We have discovered a new heavy-fermion system, CeCu6, with a large susceptibility (=0.027 emu/mole G at 1.5 K) and a large, temperature-dependent specific heat below 10 K that is 840 mJ/mole K2 at 1.8 K and extrapolates to 1.6 J/mole K2 at T=0 in analogy with CeAl3. High-field specific-heat measurements agree almost perfectly with a narrow-band picture first proposed for UBe13. © 1984 The American Physical Society.
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- 1984
14. Low-temperature properties of the heavy-fermion system UCd11
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Fisk, Z, Stewart, GR, Willis, JO, Ott, HR, and Hulliger, F
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Physical Sciences ,Chemical Sciences ,Engineering ,Fluids & Plasmas - Abstract
We present electrical-resistivity, magnetic-susceptibility, specific-heat, and thermal-expansion data for UCd11. The low-temperature specific heat indicates that the electronic subsystem has a highly enhanced specific heat which is partially removed by a phase transition at 5.0 K. © 1984 The American Physical Society.
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- 1984
15. Specific heat, magnetic susceptibility, and resistivity of an U0.85La0.15Al2 alloy
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Wire, MS, Stewart, GR, Johanson, WR, Fisk, Z, and Smith, JL
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Physical Sciences ,Chemical Sciences ,Engineering ,Fluids & Plasmas - Abstract
The compound UAl2 exhibits ferromagnetic spin fluctuations at low temperatures. When 15 at.% La is substituted for U in UAl2, we find the low-temperature magnetic susceptibility increases by more than a factor of 2. We have also measured specific heat on this sample at low temperatures. We find that the electronic density of states has increased by 60% and the spin-fluctuation contribution has increased by a factor of 2. We conclude from these measurements that the Stoner enhancement factor has increased by 30% and the spin-fluctuation temperature has increased by 50% as compared with UAl2. In addition, we have measured the electrical resistivity of U0.85La0.15Al2. We find the residual resistivity to be approximately an order of magnitude larger than that of UAl2. We attribute this effect to the breaking of UU bonds by the La atoms. © 1983 The American Physical Society.
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- 1983
16. Specific heat of well-characterized TiBe2 at 0 and 7 T
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Stewart, GR, Smith, JL, Giorgi, AL, and Fisk, Z
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Physical Sciences ,Chemical Sciences ,Engineering ,Fluids & Plasmas - Abstract
The low-temperature specific heat at magnetic fields of 0 and 7 T, dc susceptibility, and resistivity data for two samples of TiBe2.00 and one sample of TiBe1.94O0.05 are presented. The temperature dependence of the low-temperature specific heats of all three samples of TiBe2 is found to include an important T3lnT term, confirming that spin fluctuations are present in TiBe2, the first metal besides UAl2 where such a T3lnT term has been found. Evidence for a magnetic impurity present in one of the two pure TiBe2 samples is inferred from the measurements and confirmed by the same measurements on the sample with oxygen intentionally added. The impurity is thought to increase the low-temperature susceptibility, shape the resistivity, and cause a 3% decrease of the low-temperature specific heat in a 7-T field at lower temperatures. At higher temperatures in the impure samples, and at all temperatures in the purer sample of TiBe2, there is no change from the zero-field values in the specific heat to ± 1% in a 7-T field, in contradiction to the theoretical prediction of Béal-Monod. These field results are discussed with respect to the recent measurements of the low-temperature specific heats in a field of Pd and LuCo2. Previous low-temperature specific-heat results on TiBe2.06 and TiBe1.79Cu0.21 are also discussed. © 1982 The American Physical Society.
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- 1982
17. Possibility of Coexistence of Bulk Superconductivity and Spin Fluctuations in UPt3
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Stewart, GR, Fisk, Z, Willis, JO, and Smith, JL
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Mathematical Sciences ,Physical Sciences ,Engineering ,General Physics - Abstract
Convincing evidence has been discovered for bulk superconductivity in UPt3 at 0.54 K based on specific-heat, resistance, and ac susceptibility measurements. In addition, new evidence is presented that indicates that UPt3 is a spin-fluctuation system. If true, this is the first coexistent superconductor spin-fluctuation system. © 1984 The American Physical Society.
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- 1984
18. Characterization of single crystals of CeCu2Si2. A source of new perspectives
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Stewart, GR, Fisk, Z, and Willis, JO
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Physical Sciences ,Chemical Sciences ,Engineering ,Fluids & Plasmas - Abstract
We report the first thorough characterization of single crystals of CeCu2Si2. Measurements on these flux-grown crystals, which are not superconducting above 0.050 K, include ac susceptibility, resistivity, Hall effect, and specific heat. A review of other measurements is given, and the implications of our single-crystal data are discussed. Specifically, our data are consistent with superconductivity in CeCu2Si2 being destroyed by having too low a Kondo temperature, although TKondo is not found to be inversely proportional to as previously claimed. The entropy associated with the low-temperature specific-heat anomaly is found to be only 0.66R ln2, in contrast to the previous result of R ln2 for polycrystalline material. The lack of superconductivity in our single crystals does not appear to be due to poor stoichiometry to +5%, as proposed previously for single crystals grown by a Bridgman technique. The possibility of charge-density waves suppressing superconductivity in strain-free material is discussed, although no experimental verification is found. © 1983 The American Physical Society.
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- 1983
19. New heavy-fermion system, NpBe13, with a comparison to UBe13 and PuBe13
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Stewart, GR, Fisk, Z, Smith, JL, Willis, JO, and Wire, MS
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Physical Sciences ,Chemical Sciences ,Engineering ,Fluids & Plasmas - Abstract
We have prepared single crystals of NpBe13, Np0.68U0.32Be13, and PuBe13 and measured their resistivity, susceptibility, and specific heat down to low temperatures. NpBe13 has an itinerant-electron magnetic transition at 3.4 K, with a large temperature-dependent specific heat above this transition that is quite similar to that observed in the heavy-fermion superconductor UBe13 and a (T=0) of approximately 900 mJ/mole K2. PuBe13 may be described as a Kondo-type system, with certain inconsistencies. The data are compared to results for UBe13 and are consistent with a narrow f band at the Fermi energy in UBe13 moving lower in energy with the addition of f electrons in heavier actinide elements to create a Kondo resonance by PuBe13. © 1984 The American Physical Society.
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- 1984
20. Specific heat and electrical resistivity of CeCu6 below 1 k
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Ott, HR, Rudigier, H, Fisk, Z, Willis, JO, and Stewart, GR
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Applied Physics ,Condensed Matter Physics ,Materials Engineering ,Nanotechnology - Abstract
Results of measurements of the electrical resistivity ρ{variant} between 0.04 and 1 K and the specific heat cp between 0.06 and 1 K of annealed polycrystalline CeCu6 are reported. ρ{variant} varies proportional to T2 below 0.1 K but is linear in T above 0.6 K. The specific heat is proportional to T below 0.5 K and the electronic specific-heat parameter γ = 1.53 J mole K2. © 1985.
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- 1985
21. Polyglot Jet Finding
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Stewart Graeme Andrew, Gras Philippe, Hegner Benedikt, and Krasnopolski Atell
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Physics ,QC1-999 - Abstract
The evaluation of new computing languages for a large community, like HEP, involves comparison of many aspects of the languages’ behaviour, ecosystem and interactions with other languages. In this paper we compare a number of languages using a common, yet non-trivial, HEP algorithm: the anti- kT clustering algorithm used for jet finding. We compare specifically the algorithm implemented in Python (pure Python and accelerated with numpy and numba), and Julia, with respect to the reference implementation in C++, from Fastjet. As well as the speed of the implementation we describe the ergonomics of the language for the coder, as well as the efforts required to achieve the best performance, which can directly impact on code readability and sustainability.
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- 2024
- Full Text
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22. Is Julia ready to be adopted by HEP?
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Gál Tamás, Gras Philippe, Hegner Benedikt, Hernandez Acosta Uwe, Kluth Stefan, Ling Jerry, Mato Pere, Moreno Alexander, Pivarski Jim, Schulz Oliver, Stewart Graeme, Strube Jan, and Vasilev Vasil
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Physics ,QC1-999 - Abstract
The Julia programming language was created 10 years ago and is now a mature and stable language with a large ecosystem including more than 8,000 third-party packages. It was designed for scientific programming to be a high-level and dynamic language as Python is, while achieving runtime performances comparable to C/C++ or even faster. With this, we ask ourselves if the Julia language and its ecosystem is ready now for its adoption by the High Energy Physics community. We will report on a number of investigations and studies of the Julia language that have been done for various representative HEP applications, ranging from computing intensive initial data processing of experimental data and simulation, to final interactive data analysis and plotting. Aspects of collaborative code development of large software within a HEP experiment has also been investigated: scalability with large development teams, continuous integration and code test, code reuse, language interoperability to enable an adiabatic migration of packages and tools, software installation and distribution, training of the community, benefit from development from industry and academia from other fields.
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- 2024
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23. Key4hep: Progress Report on Integrations
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Brondolin Erica, Carceller Juan Miguel, Deconinck Wouter, Fang Wenxing, Francois Brieuc, Gaede Frank-Dieter, Ganis Gerardo, Hegner Benedikt, Helsens Clement, Huang Xingtao, Joosten Sylvester, Ko Sang Hyun, Lin Tao, Li Teng, Li Weidong, Madlener Thomas, Reichenbach Leonhard, Sailer André, Sasikumar Swathi, Smiesko Juraj, Stewart Graeme A., Tolosa-Delgado Alvaro, Volkl Valentin, Zhang Xiaomei, and Zou Jiaheng
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Physics ,QC1-999 - Abstract
Detector studies for future experiments rely on advanced software tools to estimate performance and optimize their design and technology choices. The Key4hep project provides a flexible turnkey solution for the full experiment life-cycle based on established community tools such as ROOT, Geant4, DD4hep, Gaudi, podio and spack. Members of the CEPC, CLIC, EIC, FCC, and ILC communities have joined to develop this framework and have merged, or are in the progress of merging, their respective software environments into the Key4hep stack. These proceedings will give an overview over the recent progress in the Key4hep project: covering the developments towards adaptation of state-of-theart tools for simulation (DD4hep, Gaussino), track and calorimeter reconstruction (ACTS, CLUE), particle flow (PandoraPFA), analysis via RDataFrame, and visualization with Phoenix, as well as tools for testing and validation.
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- 2024
- Full Text
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24. Software Citation in HEP: Current State and Recommendations for the Future
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Feickert Matthew, Katz Daniel S., Neubauer Mark S., Sexton-Kennedy Elizabeth, and Stewart Graeme A.
- Subjects
Physics ,QC1-999 - Abstract
In November 2022, the HEP Software Foundation and the Institute for Research and Innovation for Software in High-Energy Physics organized a workshop on the topic of Software Citation and Recognition in HEP. The goal of the workshop was to bring together different types of stakeholders whose roles relate to software citation, and the associated credit it provides, in order to engage the community in a discussion on: the ways HEP experiments handle citation of software, recognition for software efforts that enable physics results disseminated to the public, and how the scholarly publishing ecosystem supports these activities. Reports were given from the publication board leadership of the ATLAS, CMS, and LHCb experiments and HEP open source software community organizations (ROOT, Scikit-HEP, MCnet), and perspectives were given from publishers (Elsevier, JOSS) and related tool providers (INSPIRE, Zenodo). This paper summarizes key findings and recommendations from the workshop as presented at the 26th International Conference on Computing in High Energy and Nuclear Physics (CHEP 2023).
- Published
- 2024
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25. Towards podio v1.0 - A first stable release of the EDM toolkit
- Author
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Carceller Juan Miguel, Gaede Frank, Ganis Gerardo, Hegner Benedikt, Helsens Clement, Madlener Thomas, Sailer André, Stewart Graeme A., and Volkl Valentin
- Subjects
Physics ,QC1-999 - Abstract
A performant and easy-to-use event data model (EDM) is a key component of any HEP software stack. The podio EDM toolkit provides a user friendly way of generating such a performant implementation in C++ from a high level description in yaml format. Finalizing a few important developments, we are in the final stretches for release v1.0 of podio, a stable release with backward compatibility for datafiles written with podio from then on. We present an overview of the podio basics, and go into slighty more technical detail on the most important topics and developments. These include: schema evolution for generated EDMs, multithreading with podio generated EDMs, the implementation of them as well as the basics of I/O. Using EDM4hep, the common and shared EDM of the Key4hep project, we highlight a few of the smaller features in action as well as some lessons learned during the development of EDM4hep and podio. Finally, we show how podio has been integrated into the Gaudi based event processing framework that is used by Key4hep, before we conclude with a brief outlook on potential developments after v1.0.
- Published
- 2024
- Full Text
- View/download PDF
26. Assessment of the enhancement of PLGA nanoparticle uptake by dendritic cells through the addition of natural receptor ligands and monoclonal antibody
- Author
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Walters, AA, Somavarapu, S, Riitho, V, Stewart, GR, Charleston, B, Steinbach, F, Graham, SP, Walters, AA, Somavarapu, S, Riitho, V, Stewart, GR, Charleston, B, Steinbach, F, and Graham, SP
- Abstract
Targeting of specific receptors on antigen-presenting cells is an appealing prospect in the production of novel nanoparticulate vaccines. In particular, the targeting of vaccines to dendritic cell (DC) subsets has been shown in models to significantly improve the induction of immune responses. This paper describes the evaluation of natural ligands, mannan and chitosan, and monoclonal antibodies as targeting motifs to enhance uptake of PLGA nanoparticle carriers by bovine DCs. To assess enhancement of uptake after the addition of natural ligands a bovine monocyte derived DC (MoDC) model was used. For the assessment of monoclonal antibody targeting, the model was expanded to include afferent lymph DCs (ALDCs) in a competitive uptake assay. Mannan, proved unsuccessful at enhancing uptake or targeting by MoDCs. Chitosan coated particle uptake could be impeded by the addition of mannan suggesting uptake may be mediated through sugar receptors. Inclusion of monoclonal antibodies specific for the DEC-205 (CD205) receptor increased the number of receptor expressing DCs associated with particles as well as the number of particles taken up by individual cells. These results support the further evaluation of active targeting of nanovaccines to DCs to enhance their immunogenicity in cattle and other large mammalian species including humans.
- Published
- 2015
27. Ground state inCeAl3: ACe1−xLaxAl3study
- Author
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C.S. Jee, Andraka B, and Stewart Gr
- Subjects
Physics ,Condensed matter physics ,Specific heat ,Doping ,Antiferromagnetism ,Lanthanum compounds ,Crystal structure ,Sensitivity (control systems) ,Ground state - Abstract
By performing La doping on the Ce sites we have demonstrated that the heavy-fermion ground state in CeAl{sub 3} is extremely unstable toward local-moment antiferromagnetism. Profound changes in the low-temperature specific heat are already seen at the 1% doping level. We believe that this sensitivity to structural/chemical modifications is responsible for a large number of the mutually contradictory experimental results reported for CeAl{sub 3}. Further, we propose that the weak {ital C}/{ital T} structure observed for some CeAl{sub 3} samples near 0.4 K has a magnetic origin.
- Published
- 1995
28. Specific heat ofCe1−xMxCu6(M=La, Th, Y, and Pr)
- Author
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Stewart Gr and Kim Js
- Subjects
Physics ,Crystallography ,Condensed matter physics ,Specific heat ,Magnetic susceptibility - Abstract
Ce[sub 1[minus][ital x]]La[sub [ital x]]Cu[sub 6] is known to have a [gamma] [[equivalent to][ital C]/[ital T] ([ital T][r arrow]0)] per Ce mole that [ital increases] monotonically with increasing La concentration: [gamma] of Ce[sub 0.1]La[sub 0.9]Cu[sub 6] is [similar to]2.3 J/Ce mole K[sup 2] while that for pure CeCu[sub 6] is only 1.6 J/Ce mole K[sup 2]. To investigate this behavior, unusual in comparison with, e.g., UBe[sub 13] or CeCu[sub 2]Si[sub 2], the properties (including specific heat to 0.4 K, dc susceptibility to 1.8 K, and resistivity) of Ce[sub 1[minus][ital x]M[ital x]]Cu[sub 6], [ital M]=La, Th, Y, and Pr, 0[le][ital x][le]1, have been investigated, with the most extensive work being on La and Th. [chi] (1.8 K) remains essentially constant to [ital x]=0.4 for Th and La doping, and then rises (falls) for further La (Th) doping, with values for [ital x]=0.1 of 45.7 memu/Ce mole for La and 19.3 memu/Ce mole for Th versus 36.7 memu/mole for pure CeCu[sub 6]. While the specific-heat [gamma] values, as previously reported, increase essentially linearly upon increasing La doping, the [gamma] values for Th doping remain essentially constant up to [ital x]=0.4, and then [ital decrease] monotonically upon further Th doping, reaching [gamma]=500 mJ/Cemore » mole K[sup 2] for [ital x]=0.9.« less
- Published
- 1994
29. Detection and strain typing of ancient Mycobacterium leprae from a medieval leprosy hospital.
- Author
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Taylor, GM, Tucker, K, Butler, R, Pike, AW, Lewis, J, Roffey, S, Marter, P, Lee, OY, Wu, HH, Minnikin, DE, Besra, GS, Singh, P, Cole, ST, Stewart, GR, Taylor, GM, Tucker, K, Butler, R, Pike, AW, Lewis, J, Roffey, S, Marter, P, Lee, OY, Wu, HH, Minnikin, DE, Besra, GS, Singh, P, Cole, ST, and Stewart, GR
- Abstract
Nine burials excavated from the Magdalen Hill Archaeological Research Project (MHARP) in Winchester, UK, showing skeletal signs of lepromatous leprosy (LL) have been studied using a multidisciplinary approach including osteological, geochemical and biomolecular techniques. DNA from Mycobacterium leprae was amplified from all nine skeletons but not from control skeletons devoid of indicative pathology. In several specimens we corroborated the identification of M. leprae with detection of mycolic acids specific to the cell wall of M. leprae and persistent in the skeletal samples. In five cases, the preservation of the material allowed detailed genotyping using single-nucleotide polymorphism (SNP) and multiple locus variable number tandem repeat analysis (MLVA). Three of the five cases proved to be infected with SNP type 3I-1, ancestral to contemporary M. leprae isolates found in southern states of America and likely carried by European migrants. From the remaining two burials we identified, for the first time in the British Isles, the occurrence of SNP type 2F. Stable isotope analysis conducted on tooth enamel taken from two of the type 3I-1 and one of the type 2F remains revealed that all three individuals had probably spent their formative years in the Winchester area. Previously, type 2F has been implicated as the precursor strain that migrated from the Middle East to India and South-East Asia, subsequently evolving to type 1 strains. Thus we show that type 2F had also spread westwards to Britain by the early medieval period.
- Published
- 2013
30. Bayesian Optimization for Adaptive Experimental Design: A Review
- Author
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Stewart Greenhill, Santu Rana, Sunil Gupta, Pratibha Vellanki, and Svetha Venkatesh
- Subjects
Bayesian methods ,design for experiments ,design optimization ,machine learning algorithms ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 - Abstract
Bayesian optimisation is a statistical method that efficiently models and optimises expensive “black-box” functions. This review considers the application of Bayesian optimisation to experimental design, in comparison to existing Design of Experiments (DOE) methods. Solutions are surveyed for a range of core issues in experimental design including: the incorporation of prior knowledge, high dimensional optimisation, constraints, batch evaluation, multiple objectives, multi-fidelity data, and mixed variable types.
- Published
- 2020
- Full Text
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31. Possible marginal-Fermi-liquid behavior in dopedUPt3
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Andraka B, Jung-Do Kim, and Stewart Gr
- Subjects
Physics ,Specific heat ,Condensed matter physics ,Doping ,Binary alloy ,Champ magnetique ,Fermi liquid theory ,Current (fluid) ,Magnetic field - Abstract
The unusual temperature dependence of the specific heat previously observed in U(Pt 0.94 Pd 0.06 ) 3 for T
- Published
- 1992
32. The genetic requirements for fast and slow growth in mycobacteria.
- Author
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Beste, DJ, Espasa, M, Bonde, B, Kierzek, AM, Stewart, GR, McFadden, J, Beste, DJ, Espasa, M, Bonde, B, Kierzek, AM, Stewart, GR, and McFadden, J
- Abstract
Mycobacterium tuberculosis infects a third of the world's population. Primary tuberculosis involving active fast bacterial replication is often followed by asymptomatic latent tuberculosis, which is characterised by slow or non-replicating bacteria. Reactivation of the latent infection involving a switch back to active bacterial replication can lead to post-primary transmissible tuberculosis. Mycobacterial mechanisms involved in slow growth or switching growth rate provide rational targets for the development of new drugs against persistent mycobacterial infection. Using chemostat culture to control growth rate, we screened a transposon mutant library by Transposon site hybridization (TraSH) selection to define the genetic requirements for slow and fast growth of Mycobacterium bovis (BCG) and for the requirements of switching growth rate. We identified 84 genes that are exclusively required for slow growth (69 hours doubling time) and 256 genes required for switching from slow to fast growth. To validate these findings we performed experiments using individual M. tuberculosis and M. bovis BCG knock out mutants. We have demonstrated that growth rate control is a carefully orchestrated process which requires a distinct set of genes encoding several virulence determinants, gene regulators, and metabolic enzymes. The mce1 locus appears to be a component of the switch to slow growth rate, which is consistent with the proposed role in virulence of M. tuberculosis. These results suggest novel perspectives for unravelling the mechanisms involved in the switch between acute and persistent TB infections and provide a means to study aspects of this important phenomenon in vitro.
- Published
- 2009
33. Magnetic field study of the 'hidden transition' in UCd 11
- Author
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Rotundu, CR, Rotundu, CR, Andraka, B, Stewart, GR, Takano, Y, Fisk, Z, Rotundu, CR, Rotundu, CR, Andraka, B, Stewart, GR, Takano, Y, and Fisk, Z
- Abstract
The specific heat of U Cd11 was measured in magnetic fields to 27 T. Besides the antiferromagnetic transition, there is a second transition that can be clearly resolved in fields between 14 and 20 T. This second transition (at Tm) extrapolates to a broad shoulder in CT in zero field. The two lines of transitions cross somewhere between 20 and 23 T. Tm displays unusually weak dependence on the strength of the magnetic field. Our results argue for the intrinsic origin of this "hidden" transition. © 2005 American Institute of Physics.
- Published
- 2005
34. Plant Viruses Transmitted in Two Different Modes Produce Differing Effects on Small RNA-Mediated Processes in Their Aphid Vector
- Author
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Patricia V. Pinheiro, Jennifer R. Wilson, Yi Xu, Yi Zheng, Ana Rita Rebelo, Somayeh Fattah-Hosseini, Angela Kruse, Rogerio Santos Dos Silva, Yimin Xu, Matthew Kramer, James Giovannoni, Zhangjun Fei, Stewart Gray, and Michelle Heck
- Subjects
Plant culture ,SB1-1110 ,Microbial ecology ,QR100-130 ,Plant ecology ,QK900-989 - Abstract
Transmission of plant viruses by aphids involves multitrophic interactions among host plants, aphid vectors, and plant viruses. Here, we used small RNA (sRNA) sequencing to visualize the sRNA response of Myzus persicae to two plant viruses that M. persicae transmits in different modes: the nonpersistent Potato virus Y (PVY) versus the persistent Potato leafroll virus (PLRV). Aphids exposed to PLRV produced significantly less 22 mers aligned to the aphid genome, and an abundance of 26 to 27 mers, many of which were predicted to be piRNA. Additionally, expression of Buchnera aphidicola tRNA-derived sRNAs was influenced by PLRV and, to a lesser extent, PVY, suggesting that plant viruses alter the aphid-endosymbiont relationship. Finally, aphids exposed to PLRV-infected plants generated an abundance of unusually long sRNAs and a reduced number of 22 mers against an aphid virus, Myzus persicae densovirus (MpDNV) and had higher MpDNV titer. Expression of the PLRV silencing suppressor P0 in plants recapitulated the increase in MpDNV titer in the absence of PLRV infection. Our results show that plant viruses transmitted in two different modes cause distinct effects on their vector with regards to post-transcriptional gene regulation, symbiosis with Buchnera, and the antiviral immune response of aphids to an aphid-infecting densovirus.
- Published
- 2019
- Full Text
- View/download PDF
35. UK Chiari 1 Study: protocol for a prospective, observational, multicentre study
- Author
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Joseph Merola, Julie Woodfield, Linda D’Antona, Richard Edwards, Jothy Kandasamy, Paul Leach, Mano Shanmuganathan, Saurabh Sinha, Dominic Thompson, Lewis Thorne, Ahmed Toma, Shungu Ushewokunze, Laurence Watkins, James Stewart, Angelos G Kolias, Jayaratnam Jayamohan, Pasquale Gallo, Navneet Singh, Ashwin Kumaria, Rhannon Lobo, Marianne Hare, Louise Young, Ardalan Zolnourian, Rory J Piper, Daniel Thompson, Greg James, Georgios Tsermoulas, Rosa Sun, William B Lo, Wai Cheong Soon, Babar Vaqas, Muhammad Kamal, Fardad T Afshari, Edward W Dyson, Rodney Laing, Aabir Chakraborty, Adrian Casey, Adriana Baritchii, Alexandros Vyziotis, Ali Nader-Sephai, Alistair Jenkins, Amin Andalib, Anan Shtaya, Andrew Alalade, Andrew Brodbelt, Arup Ray, Asfand Baig Mirza, Aswin Chari, Barrie White, Benedetta Pettorini, Chandrasekaran Kaliaperumal, Danyal Khan, Dardis Ronan, David Choi, David Rowland, Edward Jerome St George, Eleni Maratos, Grainne McKenna, Hani Marcus, Hasan Asif, Hugo Layard Horsfall, Ian Kamaly-Asl, Ibrahim Jalloh, Jawad Naushahi, Joe M Das, John Duddy, Jonathan Funnell, Justyna Ekert, Kevin Tsang, Lizkerry Odeh, Makinah Haq, Mansoor Foroughi, Mark Nowell, Matthew Boissaud-Cooke, Melissa Gough, Menaka Paranathala, Micaela Uberti, Michael Cearns, Milan Makwana, Milo Hollingworth, Ming Yao Chong, Musa China, Nadia Salloum, Nicholas Haden, Nikolaos Tzerakis, Oscar MacCormac, Peter McGarrity, Rudrajit Kanjilal, Ryan Waters, Saeed Kayhanian, Samuel Jeffery, Setthasorn Zhi Yang Ooi, Shabin Joshi, Shady Elsayed, Shafqat Bukhari, Shailendra Magdum, Siddharth Sinha, Simon Lammy, Stana Bojanic, Stewart Griffiths, Teresa Scott, Thomas Carroll, Vasileios Raptopoulos, Vivek Josan, Yasir Chowdhury, and Zubair Tahir
- Subjects
Medicine - Abstract
Introduction Chiari 1 malformation (CM1) is a structural abnormality of the hindbrain characterised by the descent of the cerebellar tonsils through the foramen magnum. The management of patients with CM1 remains contentious since there are currently no UK or international guidelines for clinicians. We therefore propose a collaborative, prospective, multicentre study on the investigation, management and outcome of CM1 in the UK: the UK Chiari 1 Study (UKC1S). Our primary objective is to determine the health-related quality of life (HRQoL) in patients with a new diagnosis of CM1 managed either conservatively or surgically at 12 months of follow-up. We also aim to: (A) determine HRQoL 12 months following surgery; (B) measure complications 12 months following surgery; (C) determine the natural history of patients with CM1 treated conservatively without surgery; (D) determine the radiological correlates of presenting symptoms, signs and outcomes; and (E) determine the scope and variation within UK practice in referral patterns, patient pathways, investigations and surgical decisions.Methods and analysis The UKC1S will be a prospective, multicentre and observational study that will follow the British Neurosurgical Trainee Research Collaborative model of collaborative research. Patients will be recruited after attending their first neurosurgical outpatient clinic appointment. Follow-up data will be collected from all patients at 12 months from baseline regardless of whether they are treated surgically or not. A further 12-month postoperative follow-up timepoint will be added for patients treated with decompressive surgery. The study is expected to last three years.Ethics and dissemination The UKC1S received a favourable ethical opinion from the East Midlands Leicester South Research Ethics Committee (REC reference: 20/EM/0053; IRAS 269739) and the Health Research Authority. The results of the study will be published in peer-reviewed medical journals, presented at scientific conferences, shared with collaborating sites and shared with participant patients if they so wish.
- Published
- 2021
- Full Text
- View/download PDF
36. Transmission modes affect the population structure of potato virus Y in potato.
- Author
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Washington da Silva, Denis Kutnjak, Yi Xu, Yimin Xu, James Giovannoni, Santiago F Elena, and Stewart Gray
- Subjects
Immunologic diseases. Allergy ,RC581-607 ,Biology (General) ,QH301-705.5 - Abstract
Transmission is a crucial part of a viral life cycle and transmission mode can have an important impact on virus biology. It was demonstrated that transmission mode can influence the virulence and evolution of a virus; however, few empirical data are available to describe the direct underlying changes in virus population structure dynamics within the host. Potato virus Y (PVY) is an RNA virus and one of the most damaging pathogens of potato. It comprises several genetically variable strains that are transmitted between plants via different transmission modes. To investigate how transmission modes affect the within-plant viral population structure, we have used a deep sequencing approach to examine the changes in the genetic structure of populations (in leaves and tubers) of three PVY strains after successive passages by horizontal (aphid and mechanical) and vertical (via tubers) transmission modes. Nucleotide diversities of viral populations were significantly influenced by transmission modes; lineages transmitted by aphids were the least diverse, whereas lineages transmitted by tubers were the most diverse. Differences in nucleotide diversities of viral populations between leaves and tubers were transmission mode-dependent, with higher diversities in tubers than in leaves for aphid and mechanically transmitted lineages. Furthermore, aphid and tuber transmissions were shown to impose stronger genetic bottlenecks than mechanical transmission. To better understand the structure of virus populations within the host, transmission mode, movement of the virus within the host, and the number of replication cycles after transmission event need to be considered. Collectively, our results suggest a significant impact of virus transmission modes on the within-plant diversity of virus populations and provide quantitative fundamental data for understanding how transmission can shape virus diversity in the natural ecosystems, where different transmission modes are expected to affect virus population structure and consequently its evolution.
- Published
- 2020
- Full Text
- View/download PDF
37. 13C Natural Abundance in Plant Communities Along a Rainfall Gradient: a Biological Integrator of Water Availability
- Author
-
Stewart, GR, primary, Turnbull, MH, additional, Schmidt, S, additional, and Erskine, PD, additional
- Published
- 1995
- Full Text
- View/download PDF
38. Evidence That Glutamate Dehydrogenase Plays a Role in the Oxidative Deamination of Glutamate in Seedlings of Zea mays
- Author
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Stewart, GR, primary, Shatilov, VR, additional, Turnbull, MH, additional, Robinson, SA, additional, and Goodall, R, additional
- Published
- 1995
- Full Text
- View/download PDF
39. Tissue nutrient content of Gracilaria spp. (Rhodophyta) and water quality along an estuarine gradient
- Author
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Horrocks, JL, primary, Stewart, GR, additional, and Dennison, WC, additional
- Published
- 1995
- Full Text
- View/download PDF
40. Mapping Loci That Control Tuber and Foliar Symptoms Caused by PVY in Autotetraploid Potato (Solanum tuberosum L.)
- Author
-
Washington L. da Silva, Jason Ingram, Christine A. Hackett, Joseph J. Coombs, David Douches, Glenn J. Bryan, Walter De Jong, and Stewart Gray
- Subjects
genetic linkage map ,QTL ,autotetraploid potato ,single-nucleotide polymorphism ,Potato Virus Y ,PTNRD ,Genetics ,QH426-470 - Abstract
Potato tuber necrotic ringspot disease (PTNRD) is a tuber deformity associated with infection by the tuber necrotic strain of Potato virus Y (PVYNTN). PTNRD negatively impacts tuber quality and marketability, and poses a serious threat to seed and commercial potato production worldwide. PVYNTN symptoms differ in the cultivars Waneta and Pike: Waneta expresses severe PTNRD and foliar mosaic with vein and leaf necrosis, whereas Pike does not express PTNRD and mosaic is the only foliar symptom. To map loci that influence tuber and foliar symptoms, 236 F1 progeny of a cross between Waneta and Pike were inoculated with PVYNTN isolate NY090029 and genotyped using 12,808 potato SNPs. Foliar symptom type and severity were monitored for 10 wk, while tubers were evaluated for PTNRD expression at harvest and again after 60 d in storage. Pairwise correlation analyses indicate a strong association between PTNRD and vein necrosis (τ = 0.4195). QTL analyses revealed major-effect QTL on chromosomes 4 and 5 for mosaic, 4 for PTNRD, and 5 for foliar necrosis symptoms. Locating QTL associated with PVY-related symptoms provides a foundation for breeders to develop markers that can be used to eliminate potato clones with undesirable phenotypes, e.g., those likely to develop PTNRD or to be symptomless carriers of PVY.
- Published
- 2017
- Full Text
- View/download PDF
41. Rapid Bayesian optimisation for synthesis of short polymer fiber materials
- Author
-
Cheng Li, David Rubín de Celis Leal, Santu Rana, Sunil Gupta, Alessandra Sutti, Stewart Greenhill, Teo Slezak, Murray Height, and Svetha Venkatesh
- Subjects
Medicine ,Science - Abstract
Abstract The discovery of processes for the synthesis of new materials involves many decisions about process design, operation, and material properties. Experimentation is crucial but as complexity increases, exploration of variables can become impractical using traditional combinatorial approaches. We describe an iterative method which uses machine learning to optimise process development, incorporating multiple qualitative and quantitative objectives. We demonstrate the method with a novel fluid processing platform for synthesis of short polymer fibers, and show how the synthesis process can be efficiently directed to achieve material and process objectives.
- Published
- 2017
- Full Text
- View/download PDF
42. Neurosurgical Care of Nonpowder Firearm Injuries: A Narrative Review of the Literature
- Author
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Yizhou Wan, Stewart Griffiths, and Mario Ganau
- Subjects
Medical emergencies. Critical care. Intensive care. First aid ,RC86-88.9 - Abstract
Background. Nonpowder firearms discharge a projectile using compressed gases. Unlike traditional firearms, there is a perception that nonpowder guns do not cause serious injury. However, intracranial injury disproportionally affects children and can cause significant neurological disabilities and mortality. Management of nonpowder firearm injuries has received little attention in the literature and presents unique surgical challenges. Materials and Methods. We conducted a narrative review of the literature of the management of nonpowder firearm injuries with particular emphasis on intracranial injury. Results. Modern nonpowder firearms have muzzle velocities which are capable of penetrating the skin, eyes, and bone. Direct intracranial injury commonly results from entrance of projectile through thinner portions of the skull. Operative intervention is needed to debride and safely explore the trajectory to remove fragments which can easily cause neurovascular injury. Conclusions. Neurosurgeons play a crucial role in managing serious nonpowder firearm injuries. A multidisciplinary team is needed to manage the direct results of penetrating injury and long-term sequalae.
- Published
- 2019
- Full Text
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43. EDM4hep and podio - The event data model of the Key4hep project and its implementation
- Author
-
Gaede Frank, Ganis Gerardo, Hegner Benedikt, Helsens Clement, Madlener Thomas, Sailer Andre, Stewart Graeme A, Volkl Valentin, and Wang Joseph
- Subjects
Physics ,QC1-999 - Abstract
The EDM4hep project aims to design the common event data model for the Key4hep project and is generated via the podio toolkit. We present the first version of EDM4hep and discuss some of its use cases in the Key4hep project. Additionally, we discuss recent developments in podio, like the updates of the automatic code generation and also the addition of a second I/O backend based on SIO. We compare the available backends using benchmarks based on physics use cases, before we conclude with a discussion of currently ongoing work and future developments.
- Published
- 2021
- Full Text
- View/download PDF
44. CHEP 2021: Preface to the Proceedings
- Author
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Biscarat Catherine, Campana Simone, Hegner Benedikt, Roiser Stefan, Rovelli Chiara I., and Stewart Graeme A.
- Subjects
Physics ,QC1-999 - Abstract
The 25th International Conference on Computing in High Energy and Nuclear Physics (CHEP), organised by CERN, took place as a virtual event from 17–21 May 2021. The conference attracted 1144 registered participants from 46 different countries. There were 207 scientific presentations made over the 5 days of the conference. These were divided between 30 long talks and 2 keynotes, which were presented in plenary sessions; and 175 short talks, which were presented in parallel sessions.
- Published
- 2021
- Full Text
- View/download PDF
45. Towards a Turnkey Software Stack for HEP Experiments
- Author
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Sailer André, Ganis Gerardo, Mato Pere, Petrič Marko, and Stewart Graeme A.
- Subjects
Physics ,QC1-999 - Abstract
Future HEP experiments require detailed simulation and advanced reconstruction algorithms to explore the physics reach of their proposed machines and to design, optimise, and study the detector geometry and performance. To synergize the development of the CLIC and FCC software efforts, the CERN EP R&D roadmap proposes the creation of a “Turnkey Software Stack”, which is foreseen to provide all the necessary ingredients, from simulation to analysis, for future experiments; not only CLIC and FCC, but also for proposed Super-tau-charm factories, CEPC, and ILC. The software stack will facilitate writing specific software for experiments ensuring coherency and maximising the re-use of established packages to benefit from existing solutions and community developments, for example, ROOT, Geant4, DD4hep, Gaudi and podio. As a showcase for the software stack, the existing CLIC reconstruction software, written for iLCSoft, is being to be ported to Gaudi. In parallel, the back-end of the LCIO event data model can be replaced by an implementation in podio. These changes will enable the sharing of the algorithms with other users of the software stack. We will present the current status and plans of the turnkey software stack, with a focus of the adaptation of the CLIC reconstruction chain to Gaudi and podio, and detail the plans for future developments to generalise their applicability to FCC and beyond.
- Published
- 2020
- Full Text
- View/download PDF
46. New developments in cost modeling for the LHC computing
- Author
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Biscarat Catherine, Boccali Tommaso, Bonacorsi Daniele, Bozzi Concezio, Costanzo Davide, Duellmann Dirk, Elmsheuser Johannes, Fede Eric, Flix Molina José, Giordano Domenico, Grigoras Costin, Iven Jan, Jouvin Michel, Kemp Yves, Lange David, Maganza Riccardo, Meinhard Helge, Michelotto Michele, Roy Gareth Douglas, Sansum Andrew, Sartirana Andrea, Schulz Markus, Sciabà Andrea, Smirnova Oxana, Stewart Graeme, Valassi Andrea, Vernet Renaud, Wenaus Torre, and Wuerthwein Frank
- Subjects
Physics ,QC1-999 - Abstract
The increase in the scale of LHC computing during Run 3 and Run 4 (HL-LHC) will certainly require radical changes to the computing models and the data processing of the LHC experiments. The working group established by WLCG and the HEP Software Foundation to investigate all aspects of the cost of computing and how to optimise them has continued producing results and improving our understanding of this process. In particular, experiments have developed more sophisticated ways to calculate their resource needs, we have a much more detailed process to calculate infrastructure costs. This includes studies on the impact of HPC and GPU based resources on meeting the computing demands. We have also developed and perfected tools to quantitatively study the performance of experiments workloads and we are actively collaborating with other activities related to data access, benchmarking and technology cost evolution. In this contribution we expose our recent developments and results and outline the directions of future work.
- Published
- 2020
- Full Text
- View/download PDF
47. CHEP 2019: Preface to the Proceedings
- Author
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Doglioni Caterina, Jackson Paul, Kamleh Waseem, Kim Doris Y., Silvestris Lucia, and Stewart Graeme A.
- Subjects
Physics ,QC1-999 - Abstract
The 24th International Conference on Computing in High Energy and Nuclear Physics (CHEP) took place at the Adelaide Convention Centre, Adelaide, South Australia from 4–8 November 2019. 525 registered participants took part in the conference, where there were plenary sessions as well as a wide ranging set of ten parallel tracks across all areas of work in the field and allied sciences. The conference hosted 34 plenary presentations, 370 oral presentations in parallel sessions and 131 posters.
- Published
- 2020
- Full Text
- View/download PDF
48. PODIO: recent developments in the Plain Old Data EDM toolkit
- Author
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Gaede Frank, Hegner Benedikt, and Stewart Graeme A.
- Subjects
Physics ,QC1-999 - Abstract
PODIO is a C++ toolkit for the creation of event data models (EDMs) with a fast and efficient I/O layer. It employs plain-old-data (POD) data structures wherever possible, while avoiding deep object-hierarchies and virtual inheritance. A lightweight layer of handle classes provides the necessary highlevel interface for the physicist. PODIO creates all EDM code from simple instructive YAML files, describing the actual EDM entities. Since its original development PODIO has been very actively used for Future Circular Collider (FCC) studies. In its original version, the underlying I/O was entirely based on the automatic streaming code generated with ROOT dictionaries. Recently two additional I/O implementations have been added. One is based on HDF5 and the other uses SIO, a simple binary I/O library provided by LCIO. We briefly introduce the main features of PODIO and then report on recent developments with a focus on performance comparisons between the available I/O implementations. We conclude with presenting recent activities on porting the well-established LCIO EDM to PODIO and the recent EDM4hep project.
- Published
- 2020
- Full Text
- View/download PDF
49. Modern Software Stack Building for HEP
- Author
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Stewart Graeme A., Morgan Benjamin, Cervantes Villanueva Javier, and Willett Hobbs A.
- Subjects
Physics ,QC1-999 - Abstract
High-Energy Physics has evolved a rich set of software packages that need to work harmoniously to carry out the key software tasks needed by experiments. The problem of consistently building and deploying these packages as a coherent software stack is one that is shared across the HEP community. To that end the HEP Software Foundation Packaging Working Group has worked to identify common solutions that can be used across experiments, with an emphasis on consistent, reproducible builds and easy deployment into CernVM-FS or containers via CI systems. We based our approach on well-identified use cases and requirements from many experiments. In this paper we summarise the work of the group in the last year and how we have explored various approaches based on package managers from industry and the scientific computing community. We give details about a solution based on the Spack package manager which has been used to build the software required by the SuperNEMO and FCC experiments and trialled for a multi-experiment software stack, Key4hep. We shall discuss changes that needed to be made to Spack to satisfy all our requirements. We show how support for a build environment for software developers is provided.
- Published
- 2020
- Full Text
- View/download PDF
50. ART ATLAS Release Tester using the Grid
- Author
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Cuhadar Donszelmann Tulay, Lampl Walter, and Stewart Graeme A.
- Subjects
Physics ,QC1-999 - Abstract
The ART (ATLAS Release Tester) system is designed to run test jobs on the Grid after a nightly release of the ATLAS offline software has been built. The choice was taken to exploit the Grid as a backend as it offers a huge resource pool, suitable for a deep set of integration tests, and running the tests could be delegated to the highly scalable ATLAS production system (PanDA). The challenge of enabling the Grid as a test environment is met through the use of the CVMFS file system for the software and input data files. Test jobs are submitted to the Grid by the GitLab Continuous Integration (gitlab-ci) system, which itself is triggered at end of a release build. Jobs can be adorned with special headers that inform the system how to run the specific test, allowing many options to be customised. The gitlab-ci system waits for exit status and output files are copied back from the Grid to an EOS area accessible by users. All gitlab-ci jobs run in ART’s virtual machines, using docker images for their ATLAS setup. ART jobs can be tracked by using the PanDA system. ART can also be used to run short test jobs locally. It uses the same ART command-line interface, where the backend is replaced to access a local machine for job submission rather than the Grid. This allows developers to ensure their tests work correctly before adding them to the system. In both the Grid and local machine options, running and result copying are completely parallelized. ART is written in python, complete with its own local and Grid tests to give approximately 90% code coverage of the ART tool itself. ART has been in production for one year and fully replaces and augments the former ATLAS testing system.
- Published
- 2020
- Full Text
- View/download PDF
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