49,435 research outputs found
Quark Mass Matrices from a Softly Broken U(1) Symmetry
Assigning U(1) charges to the quarks of the standard model, and allowing one
extra scalar doublet with m^2 > 0, the correct pattern of the up and down quark
mass matrices is obtained, together with their charged-current mixing matrix.Comment: 10 pages, no figur
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Loading of trained inspiratory muscles speeds lactate recovery kinetics
Purpose: To investigate the effects of inspiratory muscle loading (ITL) and inspiratory muscle training (IMT) upon blood lactate concentration ([lacj]B)and acid-base balance following maximal incremental cycling.
Methods: 18 subjects were divided into a control (n = 9) or IMT group (n = 9). Prior to and following a 6 wk intervention subjects completed two maximal incremental cycling tests followed by 20 min of recovery with (ITL) or without (passive recovery; PR) a constant inspiratory resistance (15 cmH2O). The IMT group performed 6 wk pressure threshold IMT at 50% maximal inspiratory mouth pressure (MIP). Throughout recovery, acid-base balance was quantified using the physicochemical approach by measuring the strong ion difference ([SID])=[Na+]+[K+]-[ Clj]+[ lacj]), the total concentration of weak acids ([Atot j]) and the partial pressure of carbon dioxide (PCO2).
Results: Following the intervention MIP increased in the IMT group only (+34%). No differences in lactate clearance were observed between PR and ITL before the intervention in both groups and following the intervention in the control group. Following IMT, relative to PR, [lacj]B was reduced throughout ITL (min 2 to 20) by 0.66 ± 1.28 mmol·L-1 (P<0.05) and both the fast (lactate exchange) and slow (lactate clearance) velocity constants of the lactate recovery kinetics were increased (P<0.05). Relative to pre-IMT, ITL reduced plasma [H+] which was accounted for by an IMT-mediated increase in [SID] due almost exclusively to a 1.7 mmol·L-1 reduction in [lacj]B.
Conclusions: Following maximal exercise ITL affected lactate recovery kinetics only after IMT. Our data support the notion that the inspiratory muscles are capable of lactate clearance which increases [SID] and reduces [H+]. These effects may facilitate subsequent bouts of high-intensity exercise
Adiabatic Quantum Simulators
In his famous 1981 talk, Feynman proposed that unlike classical computers,
which would presumably experience an exponential slowdown when simulating
quantum phenomena, a universal quantum simulator would not. An ideal quantum
simulator would be controllable, and built using existing technology. In some
cases, moving away from gate-model-based implementations of quantum computing
may offer a more feasible solution for particular experimental implementations.
Here we consider an adiabatic quantum simulator which simulates the ground
state properties of sparse Hamiltonians consisting of one- and two-local
interaction terms, using sparse Hamiltonians with at most three-local
interactions. Properties of such Hamiltonians can be well approximated with
Hamiltonians containing only two-local terms. The register holding the
simulated ground state is brought adiabatically into interaction with a probe
qubit, followed by a single diabatic gate operation on the probe which then
undergoes free evolution until measured. This allows one to recover e.g. the
ground state energy of the Hamiltonian being simulated. Given a ground state,
this scheme can be used to verify the QMA-complete problem LOCAL HAMILTONIAN,
and is therefore likely more powerful than classical computing.Comment: 9 pages, 1 figur
Determinants of inspiratory muscle strength in healthy humans
We investigated 1) the relationship between the baseline and inspiratory muscle training (IMT) induced increase in maximal inspiratory pressure (PI,max) and 2) the relative contributions of the inspiratory chest wall muscles and the diaphragm (Poes/Pdi) to PI,max prior to and following-IMT. Experiment 1: PI,max was assessed during a Müeller manoeuvre before and after 4-wk IMT (n=30). Experiment 2: PI,max and the relative contribution of the inspiratory chest wall muscles to the diaphragm (Poes/Pdi) were assessed during a Müeller manoeuvre before and after 4-wk IMT (n=20). Experiment 1: PI,max increased 19% (P<0.01) post-IMT and was correlated with baseline PI,max (r=−0.373, P<0.05). Experiment 2: baseline PI,max was correlated with Poe/Pdi (r=0.582, P<0.05) and after IMT PI,max increased 22% and Poe/Pdi increased 5% (P<0.05). In conclusion, baseline PI,max and the contribution of the chest wall inspiratory muscles relative to the diaphragm affect, in part, baseline and IMT-induced ΔPI,max. Great care should be taken when designing future IMT studies to ensure parity in the between-subject baseline PI,max
Verifiable Origin of Neutrino Mass at TeV Scale
The physics responsible for neutrino mass may reside at or below the TeV
energy scale. The neutrino mass matrix in the
basis may then be deduced from future high-energy accelerator experiments. The
newly observed excess in the muon anomalous magnetic moment may also be
related.Comment: 9 pages, 1 figure, talk at TAUP 200
Inspiratory muscle training abolishes the blood lactate increase associated with volitional hyperpnoea superimposed on exercise and accelerates lactate and oxygen uptake kinetics at the onset of exercise
We examined the effects of inspiratory muscle training (IMT) upon volitional hyperpnoea-mediated increases in blood lactate ([lac−]B) during cycling at maximal lactate steady state (MLSS) power, and blood lactate and oxygen uptake kinetics at the onset of exercise. Twenty males formed either an IMT (n=10) or control group (n=10). Before and after a 6-wk intervention two 30 min trials were performed at MLSS (207 ± 28 W), which was determined using repeated 30 min constant power trials. The first was a reference trial, whereas during the second trial from 20-28 min participants mimicked the breathing pattern commensurate with 90% of the maximal minute ventilation (V ˙ E) measured during maximal incremental exercise. Before the intervention the MLSS [lac−]B was 3.7 ± 1.8 and 3.9 ± 1.6 mmol·L-1 in the IMT and control group, respectively
Softly Broken A_4 Symmetry for Nearly Degenerate Neutrino Masses
The leptonic Higgs doublet model of neutrino masses is implemented with an
A_4 discrete symmetry (the even permutation of 4 objects or equivalently the
symmetry of the tetrahedron) which has 4 irreducible representations: 1, 1',
1'', and 3. The resulting spontaneous and soft breaking of A_4 provides a
realistic model of charged-lepton masses as well as a nearly degenerate
neutrino mass matrix. Phenomenological consequences at and below the TeV scale
are discussed.Comment: 11 pages, no figur
Prior upper body exercise reduces cycling work capacity but not critical power
Purpose: This study examined whether metabolite accumulation, induced by prior upper body exercise, affected the power–duration relationship for leg cycle ergometry
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