This paper addresses passivity-based motion coordination of rigid bodies in the special Euclidean group SE(3) under the assumption that the agents exchange information over strongly connected graphs. ...In this paper, we especially focus on one of the motion coordination problems on SE(3) called attitude synchronization. We first develop a passivity-based distributed velocity input law to achieve attitude synchronization. Using the notion of algebraic connectivity, we then establish a connection between the speed of convergence and the structure of the interconnection graph. We also prove attitude synchronization in the leader-follower case and in the cases of communication delay and temporary communication failures. Finally, the performance of our developed control laws is demonstrated through both numerical simulation and experiments on a planar (2D) test bed.
NAD⁺ (oxidized form of NAD:nicotinamide adenine dinucleotide)–reducing soluble NiFe-hydrogenase (SH) is phylogenetically related to NADH (reduced form of NAD⁺):quinone oxidoreductase (complex I), but ...the geometrical arrangements of the subunits and Fe–S clusters are unclear. Here, we describe the crystal structures of SH in the oxidized and reduced states. The cluster arrangement is similar to that of complex I, but the subunits orientation is not, which supports the hypothesis that subunits evolved as prebuilt modules. The oxidized active site includes a six-coordinate Ni, which is unprecedented for hydrogenases, whose coordination geometry would prevent O₂ from approaching. In the reduced state showing the normal active site structure without a physiological electron acceptor, the flavin mononucleotide cofactor is dissociated, which may be caused by the oxidation state change of nearby Fe–S clusters and may suppress production of reactive oxygen species.
In the present work of the PIENU experiment, heavy neutrinos were sought in pion decays π+→μ+ν at rest by examining the observed muon energy spectrum for extra peaks in addition to the expected peak ...for a light neutrino. No evidence for heavy neutrinos was observed. Upper limits were set on the neutrino mixing matrix |Uμi|2 in the neutrino mass region of 15.7–33.8 MeV/c2, improving on previous results by an order of magnitude.
Despite the development of peroral video cholangioscopy (PVCS), no prospective multicenter studies have been undertaken to investigate the diagnostic accuracy of PVCS in biliary tract diseases. ...Therefore, the aim of this study was to clarify the accuracy of PVCS in evaluating biliary tract lesions.
This study was a prospective multicenter study at five tertiary referral centers in Japan and included 87 eligible patients with biliary tract diseases who underwent PVCS. The study evaluated the ability of PVCS to diagnose indeterminate biliary tract diseases, detect mucosal cancerous extension preoperatively in extrahepatic bile duct cancers, and predict adverse events.
The use of PVCS appearance alone correctly distinguished benign from malignant indeterminate biliary lesions in 92.1 % of patients whereas biopsy alone was accurate in 85.7 %. In extrahepatic bile duct cancer, mucosal cancer extended histologically at least 20 mm in 34.7 % (17/49) of patients. The accuracy rate of PVCS to evaluate the presence or absence of mucosal cancerous extension by endoscopic retrograde cholangiography (ERC) alone, ERC with PVCS, and ERC with PVCS + biopsy were 73.5 %, 83.7 %, and 92.9 %, respectively. Adverse events were seen in 6.9 % of PVCS patients, but no serious complications were observed.
PVCS enhanced the accurate diagnosis of biliary tract lesions by providing excellent resolution in combination with biopsy.
Hydrogen production by thermophilic anaerobic microflora enriched from sludge compost was studied by using an artificial medium containing cellulose powder. Hydrogen gas was evolved with the ...formation of acetate, ethanol, and butyrate by decomposition of the cellulose powder. The hydrogen production yield was 2.0 mol/mol-hexose by either batch or chemostat cultivation. A medium that did not contain peptone demonstrated a lower hydrogen production yield of 1.0 mol/mol-hexose with less formation of butyrate. The microbial community in the microflora was investigated through isolation of the microorganisms by both plating and denaturing gradient gel electrophoresis (DGGE) of the PCR-amplified V3 region of 16S rDNA. Sixty-eight microorganisms were isolated from the microflora and classified into nine distinct groups by genetic fingerprinting of the PCR-DGGE or by a random amplified polymorphic DNA analysis and determination of the partial sequence of 16S rDNA. Most of the isolates belonged to the cluster of the thermophilic Clostridium/Bacillus subphylum of low G+C gram-positive bacteria. Product formation by most of the isolated strains corresponded to that produced by the microflora. Thermoanaerobacterium thermosaccharolyticum was isolated in the enrichment culture with or without added peptone and was detected with strong intensity by PCR-DGGE. Two other thermophilic cellulolytic microorganisms, Clostridium thermocellum and Clostridium cellulosi, were also detected by PCR-DGGE, although they could not be isolated. These findings imply that hydrogen production from cellulose by microflora is performed by a consortium of several species of microorganisms.
A search for massive neutrinos has been made in the decay π+→e+ν. No evidence was found for extra peaks in the positron energy spectrum indicative of pion decays involving massive neutrinos (π→e+νh). ...Upper limits (90% C.L.) on the neutrino mixing matrix element |Uei|2 in the neutrino mass region 60–135 MeV/c2 were set and are an order of magnitude improvement over previous results.
A new measurement of the branching ratio R_{e/μ}=Γ(π^{+}→e^{+}ν+π^{+}→e^{+}νγ)/Γ(π^{+}→μ^{+}ν+π^{+}→μ^{+}νγ) resulted in R_{e/μ}^{exp}=1.2344±0.0023(stat)±0.0019(syst)×10^{-4}. This is in agreement ...with the standard model prediction and improves the test of electron-muon universality to the level of 0.1%.
•Disruption predictor based on high-beta plasma experimental data in JT-60U.•Input plasma parameters are selected by sparse modeling using exhaustive search.•Performance of prediction is improved by ...extracting input parameters.•Key parameters including magnetic fluctuation and its time delivered are extracted.•False alarm rate is improved considering temporal change of parameters.
Disruption is a critical phenomenon in a tokamak reactor. Although disruption causes serious damage to the reactor, its physical mechanism remains unclear. To realize a tokamak reactor, it is necessary to understand and control the disruption phenomenon. The present research constructs a disruption predictor using experimental high-beta plasma data in the JT-60U tokamak. The predictor was constructed using a support vector machine as a linear discriminant, and we focus on a variable selection problem for the binary classification by sparse modeling, specifically, exhaustively searching the best combinations of variables which maximize the predictor performance. By the sparse modeling, we found that the six input parameters as the best combinations. The selected parameters were the n = 1 mode amplitude |Brn=1| and its time derivative d|Brn=1|/dt, the plasma density (relative to the Greenwald density limit) and its time derivative, and the time derivatives of the plasma internal inductance and plasma elongation. In particular, it was identified that the parameter d|Brn=1|/dt, plays a key role on plasma disruption. We should notice that the combination with other plasma parameters is indispensable and remarkably make it possible to improve the performance of disruption prediction.
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