511 research outputs found
Sampling Plans for Control-Inspection Schemes Under Independent and Dependent Sampling Designs With Applications to Photovoltaics
The evaluation of produced items at the time of delivery is, in practice,
usually amended by at least one inspection at later time points. We extend the
methodology of acceptance sampling for variables for arbitrary unknown
distributions when additional sampling infor- mation is available to such
settings. Based on appropriate approximations of the operating characteristic,
we derive new acceptance sampling plans that control the overall operating
characteristic. The results cover the case of independent sampling as well as
the case of dependent sampling. In particular, we study a modified panel
sampling design and the case of spatial batch sampling. The latter is advisable
in photovoltaic field monitoring studies, since it allows to detect and analyze
local clusters of degraded or damaged modules. Some finite sample properties
are examined by a simulation study, focusing on the accuracy of estimation
Effects of Two Energy Scales in Weakly Dimerized Antiferromagnetic Quantum Spin Chains
By means of thermal expansion and specific heat measurements on the
high-pressure phase of (VO)PO, the effects of two energy scales of
the weakly dimerized antiferromagnetic = 1/2 Heisenberg chain are explored.
The low energy scale, given by the spin gap , is found to manifest
itself in a pronounced thermal expansion anomaly. A quantitative analysis,
employing T-DMRG calculations, shows that this feature originates from changes
in the magnetic entropy with respect to , . This term, inaccessible by specific heat, is visible only in the
weak-dimerization limit where it reflects peculiarities of the excitation
spectrum and its sensitivity to variations in .Comment: 4 pages, 4 figures now identical with finally published versio
Proteome dynamics and early salt stress response of the photosynthetic organism Chlamydomonas reinhardtii
BACKGROUND: The cellular proteome and metabolome are underlying dynamic regulation allowing rapid adaptation to changes in the environment. System-wide analysis of these dynamics will provide novel insights into mechanisms of stress adaptation for higher photosynthetic organisms. We applied pulsed-SILAC labeling to a photosynthetic organism for the first time and we established a method to study proteome dynamics in the green alga chlamydomonas reinhardtii, an emerging model system for plant biology. In addition, we combined the analysis of protein synthesis with metabolic profiling to study the dynamic changes of metabolism and proteome turnover under salt stress conditions. RESULTS: To study de novo protein synthesis an arginine auxotroph Chlamydomonas strain was cultivated in presence of stable isotope-labeled arginine for 24 hours. From the time course experiment in 3 salt concentrations we could identify more than 2500 proteins and their H/L ratio in at least one experimental condition; for 998 proteins at least 3 ratio counts were detected in the 24 h time point (0 mM NaCl). After fractionation we could identify 3115 proteins and for 1765 of them we determined their de novo synthesis rate. Consistently with previous findings we showed that RuBisCO is among the most prominent proteins in the cell; and similar abundance and turnover for the small and large RuBisCO subunit could be calculated. The D1 protein was identified among proteins with a high synthesis rates. A global median half-life of 45 h was calculated for Chlamydomonas proteins under the chosen conditions. CONCLUSION: To investigate the temporal co-regulation of the proteome and metabolome, we applied salt stress to chlamydomonas and studied the time dependent regulation of protein expression and changes in the metabolome. The main metabolic response to salt stress was observed within the amino acid metabolism. In particular, proline was up-regulated manifold and according to that an increased carbon flow within the proline biosynthetic pathway could be measured. In parallel the analysis of abundance and de novo synthesis of the corresponding enzymes revealed that metabolic rearrangements precede adjustments of protein abundance
Magnetocaloric effect and magnetic cooling near a field-induced quantum-critical point
The presence of a quantum critical point (QCP) can significantly affect the
thermodynamic properties of a material at finite temperatures T. This is
reflected, e.g., in the entropy landscape S(T, r) in the vicinity of a QCP,
yielding particularly strong variations for varying the tuning parameter r such
as pressure or magnetic field B. Here we report on the determination of the
critical enhancement of near a B-induced QCP via
absolute measurements of the magnetocaloric effect (MCE), , and demonstrate that the accumulation of entropy around the QCP can be
used for efficient low-temperature magnetic cooling. Our proof of principle is
based on measurements and theoretical calculations of the MCE and the cooling
performance for a Cu-containing coordination polymer, which is a very
good realization of a spin-1/2 antiferromagnetic Heisenberg chain - one of the
simplest quantum-critical systems.Comment: 21 pages, 4 figure
Feeding of the probiotic bacterium Enterococcus faecium NCIMB 10415 differentially affects shedding of enteric viruses in pigs
Effects of probiotic bacteria on viral infections have been described
previously. Here, two groups of sows and their piglets were fed with or
without feed supplementation of the probiotic bacterium Enterococcus faecium
NCIMB 10415. Shedding of enteric viruses naturally occurring in these pigs was
analyzed by quantitative real-time RT-PCR. No differences between the groups
were recorded for hepatitis E virus, encephalomyocarditis virus and norovirus.
In contrast, astrovirus was exclusively detected in the non-supplemented
control group. Rotavirus was shedded later and with lower amounts in the
probiotic piglet group (p < 0.05); rotavirus-shedding piglets gained less
weight than non-infected animals (p < 0.05). Serum titres of anti-rotavirus
IgA and IgG antibodies were higher in piglets from the control group, whereas
no difference was detected between sow groups. Phenotype analysis of immune
cell antigens revealed significant differences of the CD4 and CD8β (p < 0.05)
as well as CD8α and CD25 (p < 0.1) T cell populations of the probiotic
supplemented group compared to the non-supplemented control group. In
addition, differences were evident for CD21/MHCII-positive (p < 0.05) and IgM-
positive (p < 0.1) B cell populations. The results indicate that probiotic
bacteria could have effects on virus shedding in naturally infected pigs,
which depend on the virus type. These effects seem to be caused by
immunological changes; however, the distinct mechanism of action remains to be
elucidated
Magic state distillation in all prime dimensions using quantum Reed-Muller codes
We propose families of protocols for magic state distillation -- important
components of fault tolerance schemes --- for systems of odd prime dimension.
Our protocols utilize quantum Reed-Muller codes with transversal non-Clifford
gates. We find that, in higher dimensions, small and effective codes can be
used that have no direct analogue in qubit (two-dimensional) systems. We
present several concrete protocols, including schemes for three-dimensional
(qutrit) and five-dimensional (ququint) systems. The five-dimensional protocol
is, by many measures, the best magic state distillation scheme yet discovered.
It excels both in terms of error threshold with respect to depolarising noise
(36.3%) and the efficiency measure know as "yield", where, for a large region
of parameters, it outperforms its qubit counterpart by many orders of
magnitude.Comment: Updated from V1 to include results on the remarkable d=5 cas
A Raman study of the Charge-Density-Wave State in AMoO (A = K,Rb)
We report a comparative Raman spectroscopic study of the
quasi-one-dimensional charge-density-wave systems \ab (A = K, Rb). The
temperature and polarization dependent experiments reveal charge-coupled
vibrational Raman features. The strongly temperature-dependent collective
amplitudon mode in both materials differ by about 3 cm, thus revealing the role
of alkali atom. We discus the observed vibrational features in terms of
charge-density-wave ground state accompanied by change in the crystal symmetry.
A frequency-kink in some modes seen in \bb between T = 80 K and 100 K supports
the first-order lock-in transition, unlike \rb. The unusually sharp Raman
lines(limited by the instrumental response) at very low temperatures and their
temperature evolution suggests that the decay of the low energy phonons is
strongly influenced by the presence of the temperature dependent charge density
wave gap.Comment: 13 pages, 7 figure
Entanglement-assisted quantum low-density parity-check codes
This paper develops a general method for constructing entanglement-assisted
quantum low-density parity-check (LDPC) codes, which is based on combinatorial
design theory. Explicit constructions are given for entanglement-assisted
quantum error-correcting codes (EAQECCs) with many desirable properties. These
properties include the requirement of only one initial entanglement bit, high
error correction performance, high rates, and low decoding complexity. The
proposed method produces infinitely many new codes with a wide variety of
parameters and entanglement requirements. Our framework encompasses various
codes including the previously known entanglement-assisted quantum LDPC codes
having the best error correction performance and many new codes with better
block error rates in simulations over the depolarizing channel. We also
determine important parameters of several well-known classes of quantum and
classical LDPC codes for previously unsettled cases.Comment: 20 pages, 5 figures. Final version appearing in Physical Review
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