7 research outputs found
Asymptotic Analysis of the LMS Algorithm with Momentum
A widely studied filtering algorithm in signal processing is the least mean square (LMS) method, due to B. Widrow and T. Hoff, 1960. A popular extension of the LMS algorithm, which is also important in deep learning, is the LMS method with momentum, originated by S. Roy and J.J. Shynk back in 1988. This is a fixed gain (or constant step-size) version of the LMS method modified by an additional momentum term that is proportional to the last correction term. Recently, a certain equivalence of the two methods has been rigorously established by K. Yuan, B. Ying and A.H. Sayed, assuming martingale difference gradient noise. The purpose of this paper is to present the outline of a significantly simpler and more transparent asymptotic analysis of the LMS algorithm with momentum under the assumption of stationary, ergodic and mixing signals
S1.21 Thermodynamic constraints in the reversal of adenine nucleotide translocase during the reversal of F0–F1 ATP synthase caused by respiratory chain inhibition: Critical role of substrate-level phosphorylation
S1.21 Thermodynamic constraints in the reversal of adenine nucleotide translocase during the reversal of F0–F1 ATP synthase caused by respiratory chain inhibition: Critical role of substrate-level phosphorylation
The D1-D61N Mutation in <i>Synechocystis</i> sp. PCC 6803 Allows the Observation of pH-Sensitive Intermediates in the Formation and Release of O<sub>2</sub> from Photosystem II
The active site of photosynthetic water oxidation by
Photosystem
II (PSII) is a manganese–calcium cluster (Mn<sub>4</sub>CaO<sub>5</sub>). A postulated catalytic base is assumed to be crucial. CP43-Arg357,
which is a candidate for the identity of this base, is a second-sphere
ligand of the Mn<sub>4</sub>–Ca cluster and is located near
a putative proton exit pathway, which begins with residue D1-D61.
Transient absorption spectroscopy and time-resolved O<sub>2</sub> polarography
reveal that in the D1-D61N mutant, the transfer of an electron from
the Mn<sub>4</sub>CaO<sub>5</sub> cluster to Y<sub>Z</sub><sup>OX</sup> and O<sub>2</sub> release during the final step of the catalytic
cycle, the S<sub>3</sub>–S<sub>0</sub> transition, proceed
simultaneously but are more dramatically decelerated than previously
thought (<i>t</i><sub>1/2</sub> of up to ∼50 ms vs
a <i>t</i><sub>1/2</sub> of 1.5 ms in the wild type). Using
a bare platinum electrode to record the flash-dependent yields of
O<sub>2</sub> from mutant and wild-type PSII has allowed the observation
of the kinetics of release of O<sub>2</sub> from extracted thylakoid
membranes at various pH values and in the presence of deuterated water.
In the mutant, it was possible to resolve a clear lag phase prior
to the appearance of O<sub>2</sub>, indicating formation of an intermediate
before the onset of O<sub>2</sub> formation. The lag phase and the
photochemical miss factor were more sensitive to isotope substitution
in the mutant, indicating that proton efflux in the mutant proceeds
via an alternative pathway. The results are discussed in comparison
with earlier results obtained from the substitution of CP43-Arg357
with lysine and in regard to hypotheses concerning the nature of the
final steps in photosynthetic water oxidation. These considerations
led to the conclusion that proton expulsion during the initial phase
of the S<sub>3</sub>–S<sub>0</sub> transition starts with the
deprotonation of the primary catalytic base, probably CP43-Arg357,
followed by efficient proton egress involving the carboxyl group of
D1-D61 in a process that constitutes the lag phase immediately prior
to O<sub>2</sub> formation chemistry