News Article | December 7, 2016
WATERLOO, Ontario--(BUSINESS WIRE)--Knowledgehook, whose software teachers throughout North America are using to tailor their support of individual students, has secured $1.25 million in financing to fund the platform’s expansion into global markets. The round was led by Sayan Navaratnam of Aadya Capital and CEO of Connex Telecommunications and also includes investors Steve Case, co-founder of AOL, and John Abele, co-founder of Boston Scientific. “Knowledgehook has a novel solution to a global problem,” Navaratnam says. “I believe this technology will be defining for the edtech space, paving the way for how a data-driven approach to teaching can help kids all over the world do better in math.” Research suggests that throughout Canada and the United States, student’s math skills are lagging. Knowledgehook software surfaces what concepts they’re struggling with, identifies why and suggests how teachers can support them. The company’s platform is popular among teachers in more than 75% of Ontario school boards and in more than 300 school districts in the U.S. In 2016, Knowledgehook software made more than 6,000 recommendations on how best teachers could close gaps it identified in their students’ learning. Knowledgehook received early encouragement from investor Steve Case, who in May 2016 was one of three Google Demo Day judges to present the company with the annual, audience-selected Google’s Game Changer Award. “Knowledgehook is a great example of what’s happening in Waterloo. The whole edtech space is focused on some real problems. Personalized, adaptive learning systems are clearly important for the next generation of learners,” Case told Demo Day presenters. Knowledgehook, which this year was named BNN’s Top Disruptor, has expansion plans to other markets including the United Kingdom and Australia. Knowledgehook, founded in 2014, is grateful for the support of mentors from Communitech’s Rev and the Accelerator Centre’s AC JumpStart programs, and for funding delivered by Ontario Centres for Excellence (OCE). About Aadya: Aadya Capital invests and partners with highly select early stage companies, helping them to create, position and execute on their development. Aadya coaches companies, infuses them with operational efficiencies and surrounds them with resources for success.
Zhang Z.,Shanghai JiaoTong University |
Chen L.-W.,Shanghai JiaoTong University |
Chen L.-W.,Accelerator Centre
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2013
We show that the neutron skin thickness δrnp of heavy nuclei is uniquely fixed by the symmetry energy density slope L(ρ) at a subsaturation cross density ρc≈0.11 fm-3 rather than at saturation density ρ0, while the binding energy difference δE between a heavy isotope pair is essentially determined by the magnitude of the symmetry energy Esym(ρ) at the same ρc. Furthermore, we find a value of L(ρc) leads to a negative Esym(ρ0)-L(ρ0) correlation while a value of Esym(ρc) leads to a positive one. Using data on δrnp of Sn isotopes and δE of a number of heavy isotope pairs, we obtain simultaneously Esym(ρc)=26.65±0.20 MeV and L(ρc)=46.0±4.5 MeV at 95% confidence level, whose extrapolation gives Esym(ρ0)=32.3±1.0 MeV and L(ρ0)=45.2±10.0 MeV. The implication of these new constraints on the δrnp of 208Pb and the core-crust transition density in neutron stars is discussed. © 2013 Elsevier B.V.
Chen L.-W.,Shanghai JiaoTong University |
Chen L.-W.,Accelerator Centre
Physical Review C - Nuclear Physics | Year: 2011
Within the Skyrme-Hartree-Fock (SHF) approach, we show that for a fixed mass number A, both the symmetry energy coefficient asym(A) in the semiempirical mass formula and the nuclear matter symmetry energy E sym(ρA) at a subsaturation reference density ρA can be determined essentially by the symmetry energy E sym(ρ0) and its density slope L at saturation density ρ0. Meanwhile, we find the dependence of asym(A) on Esym(ρ0) or L is approximately linear and very similar to the corresponding linear dependence displayed by Esym(ρ A), providing an explanation for the relation Esym(ρ A)ρasym(A). Our results indicate that a value of Esym(ρA) leads to a linear correlation between E sym(ρ0) and L and thus can put important constraints on Esym(ρ0) and L. Particularly, the values of E sym(ρ0)=30.5±3 MeV and L= 52.5±20 MeV are simultaneously obtained by combining the constraints from recently extracted Esym(ρA=0.1 fm-3) with those from recent analyses of neutron skin thickness of Sn isotopes in the same SHF approach. © 2011 American Physical Society.
Funaki Y.,Accelerator Centre
Physical Review C - Nuclear Physics | Year: 2015
The excited states in C12 are investigated by using an extended version of the so-called Tohsaki-Horiuchi-Schuck-Röpke (THSR) wave function, where both the 3α condensate and Be8+α cluster asymptotic configurations are included. A new method is also used to resolve spurious continuum coupling with physical states. I focus on the structures of the "Hoyle band" states (02+,22+, and 42+), which were recently observed above the Hoyle state, and of the 03+ and 04+ states, which were also quite recently identified in experiment. Their resonance parameters and decay properties are reasonably reproduced. All these states have dilute density structure of the 3α or Be8+α clusters with larger root mean square radii than that of the Hoyle state. The Hoyle band is not simply considered to be the Be8(0+)+α rotation as suggested by previous cluster model calculations, nor to be a rotation of a rigid-body triangle-shaped object composed of the 3α particles. This is mainly due to the specificity of the Hoyle state, which has the 3α condensate structure and gives rise to the 03+ state with a prominent Be8(0+)+α structure as a result of very strong monopole excitation from the Hoyle state. © 2015 American Physical Society. ©2015 American Physical Society.
Yoshida K.,Accelerator Centre
Physical Review C - Nuclear Physics | Year: 2010
We investigate the roles of deformation on the giant monopole resonance (GMR), particularly the mixing of the giant quadrupole resonance (GQR) and the effects of the neutron excess in the well-deformed nuclei around Zr110 and in the drip-line nuclei around Zr140 by means of the deformed quasiparticle-random- phase approximation employing the Skyrme and the local-pairing energy-density functionals. It is found that the isoscalar (IS) GMR has a two-peak structure, the lower peak of which is associated with the mixing between the ISGMR and the Kπ=0+ component of the ISGQR. The transition strength of the lower peak of the ISGMR grows as the neutron number increases. In the drip-line nuclei, the neutron excitation is dominant over the proton excitation. We find that for an isovector (IV) excitation the GMR has a four-peak structure due to the mixing of the IS and IV modes as well as the mixing of the Kπ=0 + component of the IVGQR. In addition to the GMR, we find that the threshold strength is generated by neutrons only. © 2010 The American Physical Society.
Itahashi K.,Accelerator Centre
Acta Physica Polonica B | Year: 2014
Meson-nucleus bound systems have been providing precious information on the meson properties in nuclear medium, which is leading to understanding of non-trivial structure of the QCD vacuum. Two related experimental projects are discussed. One is a pionic atom factory project at RIBF and the other is a spectroscopy of η′-mesic nuclei in GSI/FAIR. The former is aiming at high precision systematic spectroscopy of pionic atoms followed by challenges for pionic atoms with unstable nuclei. The latter is aiming at spectroscopy of η′-mesic nuclei in (p; d) reactions by inclusive and semi-exclusive measurement.
Hiyama E.,Accelerator Centre
Nuclear Physics A | Year: 2013
The structure of the 10ΛBe and 10ΛB with an α + α + Λ + N four-body model cluster model is studied. The two-body ΛN interaction is adjusted so as to reproduce the 0 +-1 + splitting of 4ΛH. Also a phenomenological ΛN charge symmetry breaking (CSB) interaction is introduced. The ΛN CSB interaction works repulsively by +0.1MeV (attractively by -0.1MeV) in 10ΛBe (10ΛB). A neutron-rich Λ hypernucleus, 6ΛH is studied within a framework of t + Λ + n + n four-body model. As long as we reproduce the energy and width of 5H within the error bar, then ground state of 6ΛH is obtained as a resonant state. © 2013 Elsevier B.V.
Hiyama E.,Accelerator Centre
Few-Body Systems | Year: 2012
Recent development in the study of the structure of light Λ and double Λ hypernuclei is reviewed from the view point of few-body problems and interactions between the constituent particles. In the study the present author and collaborators employed Gaussian expansion method for few-body calculations; the method has been applied to many kinds of few-body systems in the fields of nuclear physics and exotic atomic/molecular physics. We reviewed the following subjects studied using the method: (1) Precise three- and four-body calculations of 7 Λ He, 7 Λ Li, 7 Λ Be, 8 Λ Li, 8 Λ Be, 9 Λ Be, 10 Λ Be, 10 Λ B and 13 Λ C provide important information on the spin structure of the underlying ΛN interaction by comparing the calculated results with the recent experimental data by γ-ray hypernuclear spectroscopy. (2) The Λ-Σ coupling effect was investigated in 4 Λ H and 4 Λ He on the basis of the N + N + N + Λ (Σ) four-body model. (3) A systematic study of double-Λ hypernuclei and the ΛΛ interaction, based on the NAGARA event data ( 6 ΛΛ He), was performed within the α + x + Λ + Λ cluster model (x = n, p, d, t, 3He and α) and α + α + n + Λ + Λ cluster model, (4) The Demachi-Yanagi event was interpreted as observation of the 2 + state of 10 ΛΛ Be, (5) The Hida event was interpreted as observation of the ground state of 11 ΛΛ Be. © 2012 Springer-Verlag.
Wada M.,Accelerator Centre
Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms | Year: 2013
In order to overcome serious limitations in the universality of the traditional isotope separator on-line technique, various endeavors have been made on gas catcher cells for converting relativistic RI-beams from in-flight separators to low-energy RI-beams. The origin of the gas catcher is found in the IGISOL (Ion guide isotope separator on-line) technique. Many developments have been made over the years to overcome the various difficulties and drawbacks found in the IGISOL technique. © 2013 Elsevier B.V. All rights reserved.
Danielewicz P.,Michigan State University |
Lee J.,Accelerator Centre
Nuclear Physics A | Year: 2014
Using excitation energies to isobaric analog states (IAS) and charge invariance, we extract nuclear symmetry coefficients, representing a mass formula, on a nucleus-by-nucleus basis. Consistently with charge invariance, the coefficients vary weakly across an isobaric chain. However, they change strongly with nuclear mass and range from a a ~ 10MeV at mass A ~ 10 to a a ~ 22MeV at A ~ 240. Variation with mass can be understood in terms of dependence of nuclear symmetry energy on density and the rise in importance of low densities within nuclear surface in smaller systems. At A ≳ 30, the dependence of coefficients on mass can be well described in terms of a macroscopic volume-surface competition formula with aaV≃33.2MeV and aaS≃10.7MeV. Our further investigation shows, though, that the fitted surface symmetry coefficient likely significantly underestimates that for the limit of half-infinite matter. Following the considerations of a Hohenberg-Kohn functional for nuclear systems, we determine how to find in practice the symmetry coefficient using neutron and proton densities, even when those densities are simultaneously affected by significant symmetry-energy and Coulomb effects. These results facilitate extracting the symmetry coefficients from Skyrme-Hartree-Fock (SHF) calculations, that we carry out using a variety of Skyrme parametrizations in the literature. For the parametrizations, we catalog novel short-wavelength instabilities. In our further analysis, we retain only those parametrizations which yield systems that are adequately stable both in the long- and short-wavelength limits. In comparing the SHF and IAS results for the symmetry coefficients, we arrive at narrow (±2.4MeV) constraints on the symmetry-energy values S(ρ) at 0.04 ≲ ρ ≲ 0.13fm -3. Towards normal density the constraints significantly widen, but the normal value of energy aaV and the slope parameter L are found to be strongly correlated. To narrow the constraints, we reach for the measurements of asymmetry skins and arrive at aaV=30.2-33.7MeV and L = 35-70MeV, with those values being again strongly positively correlated along the diagonal of their combined region. Inclusion of the skin constraints allows to narrow the constraints on S(ρ), at 0.04 ≲ ρ ≲ 0.13fm -3, down to ±1.1MeV. Several microscopic calculations, including variational, Bruckner-Hartree-Fock and Dirac-Bruckner-Hartree-Fock, are consistent with our constraint region on S(ρ). © 2013 Elsevier B.V.