Pairing of 1-hexyl-3-methylimidazolium and tetrafluoroborate ions in n-pentanol

Molecular dynamics simulations are obtained and analyzed to study pairing of 1-hexyl-3-methylimidazolium and tetrafluoroborate ions in n-pentanol, in particular by evaluating the potential-of-mean-force between counter ions. The present molecular model and simulation accurately predicts the dissociation constant Kd in comparison to experiment, and thus the behavior and magnitudes for the ion-pair pmf at molecular distances, even though the dielectric constant of the simulated solvent differs from the experimental value by about 30%. A naive dielectric model does not capture molecule structural effects such as multiple conformations and binding geometries of the Hmim+ and BF4- ion-pairs. Mobilities identify multiple time-scale effects in the autocorrelation of the random forces on the ions, and specifically a slow, exponential time-decay of those long-ranged forces associated here with dielectric friction effects.Comment: 5 pages, 7 figures. V2: Figs. 4 & 7 redrawn for better visual clarity with log-scales. No change in results. In press J. Chem. Phys. 201

Bose-Einstein condensates with attractive 1/r interaction: The case of self-trapping

Amplifying on a proposal by O'Dell et al. for the realization of Bose-Einstein condensates of neutral atoms with attractive $1/r$ interaction, we point out that the instance of self-trapping of the condensate, without external trap potential, is physically best understood by introducing appropriate "atomic" units. This reveals a remarkable scaling property: the physics of the condensate depends only on the two parameters $N^2 a/a_u$ and $\gamma/N^2$, where $N$ is the particle number, $a$ the scattering length, $a_u$ the "Bohr" radius and $\gamma$ the trap frequency in atomic units. We calculate accurate numerical results for self-trapping wave functions and potentials, for energies, sizes and peak densities, and compare with previous variational results. As a novel feature we point out the existence of a second solution of the extended Gross-Pitaevskii equation for negative scattering lengths, with and without trapping potential, which is born together with the ground state in a tangent bifurcation. This indicates the existence of an unstable collectively excited state of the condensate for negative scattering lengths.Comment: 7 pages, 7 figures, to appear in Phys. Rev.

Strength, rate of force development, power and reactive strength in adult male athletic populations post anterior cruciate ligament reconstruction - a systematic review and meta-analysis

Background Residual deficits in athletic performance are common despite rehabilitation guidelines following anterior cruciate ligament reconstruction including criterion-based progressions to protect healing structures, ensure safe restoration of fundamental physical capacities, and guide appropriate return to sports activities. A synthesis of the available literature is warranted to examine the physical readiness to re-perform of athletic populations in the later stages of rehabilitation in comparison to healthy controls. Objectives To determine the level of strength, power, rate of force development, and reactive strength in adult males who are more than six months following anterior cruciate ligament reconstruction. Methods A systematic review of the literature was undertaken using the Medline, CINAHL and SPORTDiscus databases and the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Studies including males only and assessed strength, power, rate of force development and reactive strength comparing performance to healthy controls were included. A meta-analysis was also performed to compute standardized mean differences (SMD ± 95% confidence intervals), calculated using Hedge’s g, and examine the effect of ACLR on these fundamental physical capacities. Results 2023 articles were identified, of which 14 articles with similar level of evidence and methodological quality met the inclusion criteria. The most commonly investigated and impaired physical capacity was quadriceps (g= -0.89, 95% CI [-1.33,-0.44]) and hamstring strength (g= -0.44, 95% CI [-0.78,-0.10]). Only one study investigated rate of force development and none measuring reactive strength met our eligibility criteria. Conclusions Pooled data showed moderate evidence indicating large and small negative deficits on knee peak extension and flexion, respectively, in male adults at more than 6 months post anteriorcruciate ligament reconstruction. The magnitude of these differences are influenced by graft type and can be mitigated by targeted rehabilitation programs. Insufficient evidence is available in male adults following anterior cruciate ligament reconstruction to examine rate of force development and reactive strength

Optimal local implementation of non-local quantum gates

We investigate the minimal resources that are required in the local implementation of non-local quantum gates in a distributed quantum computer. Both classical communication requirements and entanglement consumption are investigated. We present general statements on the minimal resource requirements and present optimal procedures for a number of important gates, including CNOT and Toffoli gates. We show that one bit of classical communication in each direction is both necessary and sufficient for the non-local implementation of the quantum CNOT, while in general two bits in each direction is required for the implementation of a general two bit quantum gate. In particular, the state-swapper requires this maximum classical communication overhead. Extensions of these ideas to multi-party gates are presented

Relationships between physical capacities and biomechanical variables during movement tasks in athletic populations following anterior cruciate ligament reconstruction

Background Anterior cruciate ligament (ACL) reconstruction has a detrimental impact on athletic performance. Despite rehabilitation guidelines and criterion-based progressions to ensure safe restoration of fundamental physical capacities and maladaptive movement strategies, residual deficits in maximal strength, rate of force development (RFD), power and reactive strength are commonly reported. These combined with associated compensatory inter and intra-limb strategies increase the risk of re-injury. Objective The aim of this article is to examine the relationships between fundamental physical capacities and biomechanical variables during dynamic movement tasks. Design Narrative review Results The available data suggests that quadriceps strength and rate of torque development, explain a moderate portion of the variance in aberrant kinetic and kinematic strategies commonly detected in ACL reconstructed cohorts at who are during the later stages of rehabilitation and RTS Conclusion The available data suggests that quadriceps strength and rate of torque development, explain a moderate portion of the variance in aberrant kinetic and kinematic strategies commonly detected in ACL reconstructed cohorts at who are in the later stages of rehabilitation and RT