1,134,640 research outputs found
Stretch de-spin mechanism Patent
Stretch Yo-Yo mechanism for reducing initial spin rate of space vehicl
Modified estimator of the contribution rates of population eigenvalues
Modified estimators for the contribution rates of population eigenvalues are
given under an elliptically contoured distribution. These estimators decrease
the bias of the classical estimator, i.e. the sample contribution rates. The
improvement of the modified estimators over the classical estimator are proved
theoretically in view of their risks. We also checked numerically that the
drawback of the classical estimator, namely the underestimation of the
dimension in principal component analysis or factor analysis, are corrected in
the modification.Comment: 25 page
Quantum Local Quench, AdS/BCFT and Yo-Yo String
We propose a holographic model for local quench in 1+1 dimensional Conformal
Field Theory (CFT). The local quench is produced by joining two identical CFT's
on semi-infinite lines. When these theories have a zero boundary entropy, we
use the AdS/Boundary CFT proposal to describe this process in terms of bulk
physics. Boundaries of the original CFT's are extended in AdS as dynamical
surfaces. In our holographic picture these surfaces detach from the boundary
and form a closed folded string which can propagate in the bulk. The dynamics
of this string is governed by the tensionless Yo-Yo string solution and its
subsequent evolution determines the time dependence after quench. We use this
model to calculate holographic Entanglement Entropy (EE) of an interval as a
function of time. We propose how the falling string deforms Ryu-Takayanagi's
curves. Using the deformed curves we calculate EE and find complete agreement
with field theory results.Comment: 20 pages, 13 figures, discussion improved, Version to appear in JHE
Functionalization of Rhenium Aryl Bonds by O-Atom Transfer
Aryltrioxorhenium (ArReO_3) has been demonstrated to show rapid oxy-functionalization upon reaction with O-atom donors, YO, to selectively generate the corresponding phenols in near quantitative yields. (18)^O-Labeling experiments show that the oxygen in the products is exclusively from YO. DFT studies reveal a 10.7 kcal/mol barrier (Ar = Ph) for oxy-functionalization with H_2O_2 via a Baeyer-Villiger type mechanism involving nudeophilic attack of the aryl group on an electrophilic oxygen of YO coordinated to rhenium
Effects of in-season uphill sprinting on physical characteristics in semi-professional soccer players
AIM: Soccer performance is determined by a number of physiological adaptations that can be altered by high intensity training. However, the effectiveness of using an uphill sprint based protocol has not been demonstrated for soccer players. We sought to determine the effectiveness of an in-season uphill sprint training (UST) programme on soccer related physiological outcomes. METHODS: 14 male soccer players (age: 22 Ā± 8 years, height: 1.81 Ā± 8 m, body mass: 76 Ā± 12 kg) underwent testing (5-10-5 agility drill, Yo-Yo Intermittent Recovery Test Level 1, leg and back dynamometry & 3km time trial) at baseline and after 6 weeks of UST or normal activity. Participants were allocated to a control (n=7) or UST (n=7) group. The UST group took part in twice weekly training consisting of 10 x 10 sec sprints with 60s recovery on a 7% gradient for 6 weeks. The control group maintained normal activity patterns. RESULTS: 3km time trial, strength, agility and Yo-Yo performance were all significantly improved pre to post following 6 weeks of UST (Agility 3%, d=1.3; Strength 10%, d=-3.2; VO2 max 3%, d=-1.4; 3-km TT 4%, d=1.3). In the control group 3km time trial, strength, agility and Yo-Yo performance remained unchanged after 6 weeks (Agility 0.1%, d=-0.2; Strength 2%, d=0.0; VO2 max -0.1%, d=0.0; 3-km TT 1.3%, d=0.3). CONCLUSION: Therefore in-season short duration UST is an effective way to improve soccer fitness in a time efficient manner
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