Secret key rate proof of multicarrier continuous‐variable quantum key distribution

We prove the secret key rate formulas and derive security threshold parameters of multicarrier continuous‐variable quantum key distribution CVQKD. In a multicarrier CVQKD scenario, the Gaussian input quantum states of the legal parties are granulated into Gaussian subcarrier continuous variables (CVs). The multicarrier communication formulates Gaussian subchannels from the physical quantum channel, each dedicated to the transmission of a subcarrier CV. The Gaussian subcarriers are decoded by a unitary CV operation, which results in the recovered single‐carrier Gaussian CVs. We derive the formulas through the adaptive multicarrier quadrature division (AMQD) scheme, the singular value decomposition (SVD)–assisted AMQD, and the multiuser AMQD multiuser quadrature allocation (MQA). We prove that the multicarrier CVQKD leads to improved secret key rates and higher tolerable excess noise in comparison with single‐carrier CVQKD. We derive the private classical capacity of a Gaussian subchannel and the security parameters of an optimal Gaussian collective attack in the multicarrier setting. We reveal the secret key rate formulas for one‐way and two‐way multicarrier CVQKD protocols, assuming homodyne and heterodyne measurements and direct and reverse reconciliation. The results reveal the physical boundaries of physically allowed Gaussian attacks in a multicarrier CVQKD scenario and confirm that the improved transmission rates lead to enhanced secret key rates and security thresholds.     

Computer reconstruction of luminal cross-sectional shape from multiple cineangiographic views

Knowledge of coronary luminal shape, in addition to diameter information as routinely obtained from a cineangiogram, may be useful in assessing lesions which deviate from circular symmetry. We have developed an image analysis system for automated tracking of luminal edges and measurement of diameter form cine frames digitized by a video camera/digitizer interfaced to a Vax 11/780 computer. Between vessel edges, cinedensitometric profiles across the vessel long axis are used to provide a rotationally invariant measure of relative luminal cross-sectional area. A maximum entropy iterative algorithm is used to reconstruct the lumen cross section from a set of projection data consisting of the cinedensitometric profiles from multiple radiographic views. Nonaxisymmetric model coronary lumena, such as a crescent shape and a double lumen simulating a coronary artery dissection, were filmed under cineradiographic conditions similar to clinical exposures. Radiographic views at 10 degrees increments about the model lumen long axis over 360 degrees were available for analysis. Graphic display of reconstructed model lumena indicate that as few as three to five radiographic views may be useful in reconstructing coronary luminal shape.     

High-temperature crack growth in low-cycle fatigue

The rates of low-cycle fatigue crack propagation in 1 Cr-1 Mo-0·25 V low alloy steel were determined under several types of loading at 1000 F. It was found that crack growth rates correlate well with the nominal crack tip stress. This method was also applied with good results to some published data where the fracture mechanics stress intensity factor had given only limited correlation. Several questions are thus raised regarding the relative importance of crack tip stress and crack length during crack growth in actual components.     

13C NMR chemical shifts of polyisobutylene end groups and related model compounds

Summary The detailed end-structures of CH₃-,-Cl, exo-olefin, endoolefin, and-OH ended polyisobutylenes (PIB) have been characterized by high resolution¹³C NMR spectroscopy. Specifically, the¹³C chemical shifts characteristic of the various carbons in the following structures have been determined: CH₂C(CH₃)₂-CH₂C(CH₃)₃, CH₂C(CH₃)₂CH₂C(CH₃)₂Cl, CH₂C(CH₃)₂CH₂C(CH₃)=CH₂, CH₂C(CH₃)₂CH=C(CH₃)₂, and CH₂C(CH₃)₂CH₂CH(CH₃)CH₂OH. The structure analysis of model compounds was of utmost help in these investigations. The above information is of great value for the identification of terminally functional PIBs and analysis of reaction mixtures.     

A Budding Relationship: Bacterial Extracellular Vesicles in the Microbiota-Gut-Brain Axis

The discovery of the microbiota-gut-brain axis has revolutionized our understanding of systemic influences on brain function and may lead to novel therapeutic approaches to neurodevelopmental and mood disorders. A parallel revolution has occurred in the field of intercellular communication, with the realization that endosomes, and other extracellular vesicles, rival the endocrine system as regulators of distant tissues. These two paradigms shifting developments come together in recent observations that bacterial membrane vesicles contribute to inter-kingdom signaling and may be an integral component of gut microbe communication with the brain. In this short review we address the current understanding of the biogenesis of bacterial membrane vesicles and the roles they play in the survival of microbes and in intra and inter-kingdom communication. We identify recent observations indicating that bacterial membrane vesicles, particularly those derived from probiotic organisms, regulate brain function. We discuss mechanisms by which bacterial membrane vesicles may influence the brain including interaction with the peripheral nervous system, and modulation of immune activity. We also review evidence suggesting that, unlike the parent organism, gut bacteria derived membrane vesicles are able to deliver cargo, including neurotransmitters, directly to the central nervous system and may thus constitute key components of the microbiota-gut-brain axis.     

Gas chromatography-isotope dilution mass spectrometry method validation for target pesticides in soybeans

The production of certified reference materials requires the application of highly accurate methods for characterisation. A gas chromatography-isotope dilution mass spectrometry method, setting ambitious performance criteria, was developed for eight selected pesticides in soybeans. Pressurised liquid extraction was followed by automated gel-permeation chromatography and solid-phase extraction clean-up. Pesticides identification respected a Commission Decision and guidelines of the Directorate General for Health and Food Safety (DG SANTE). Reliable quantification involved stable isotopically labelled analogues as internal standards. Validation, according to ISO/IEC 17,025 and DG SANTE guidelines, assessed linearity, LOD/LOQ, trueness, selectivity, precision, stability and robustness. Mean recoveries ranges (83–109%, relative standard deviations < 3%), repeatability (2.2–4.8%), day-to-day variation (0.6–4.2%) and combined uncertainty (1.2–4.2%) were fit for purpose. The method is highly accurate and suitable for certification of the selected pesticides in soybean matrix reference material.

Chemical compounds studied in this article: Diazinon (PubChem CID: 3017); malathion (PubChem CID: 4004); chlorpyrifos (PubChem CID: 2730); captan (PubChem CID: 8606); endosulfan (PubChem CID: 3224); tebuconazole (PubChem CID: 86,102); iprodione (PubChem CID: 37,517); cypermethrin (PubChem CID: 2912).     

Linear hydrogen adsorbate structures on graphite induced by self-assembled molecular monolayers

Combined scanning tunnelling microscopy measurements and density functional theory calculations reveal a method to induce linear structures of hydrogen adsorbates on graphite by covering the surface with a self-assembled molecular monolayer of cyanuric acid and exposing it to atomic hydrogen. The method can in principle be applied to obtain nanopatterned hydrogen structures on free standing graphene and graphene laid down on insulating substrates, hereby opening up for the possibility of substrate independent bandgap engineering of graphene.     

A new active position sensing method for ropeless elevator

Traditional cable driven elevators perform poorly in high-rise buildings because the weight of the cable limits the payload, and its elasticity degrades control performance. Further, it is not mechanically possible to include several elevator cars in the same hoistway because of the cable. However such multi-car elevator systems are desirable since they reduce passenger waiting time and reduce the space requirements of the elevator system. A promising solution is to use long armature linear motors spanning the hoistway to directly drive elevator cages. In such applications, the mover position sensing method must be explicitly addressed since most active position sensing methods require traveling cables, which are also an obstacle for multi-car elevator systems.In this paper, the linear-motor active position sensing method is formally introduced and the principle of operation, design and real-time operation methods are presented. The proposed method is used to measure the position of the mover of a long armature permanent magnet linear synchronous motor requiring no active components on the mover, thus traveling cables are eliminated. The principle of operation is inspired by linear variable differential transformer: A magnetic shunt positioned at a fixed distance ahead of the mover deforms the magnetic field created by one of the armature coils. The deformation can be determined by measuring the induced voltages on the neighboring coils, and the position of the shunt, and thus the mover, can be calculated.A design method for the optimal dimensions of the shunt for a given armature to provide long measurement range and small maximum position error is presented, accompanied by a real-time measurement algorithm that will enable the motor to be driven using the method. Finally the method is verified by simulations and experimental results conducted on a full scale linear-motor elevator prototype that was constructed in the laboratory.     

Einfluß von Futterfetten und -lecithinen auf Parameter der Infektionsabwehr beim Absatzferkel, 2. Mitteilung: Der Einfluß von Soja- oder Eilecithinen

Influence of dietary fats and lecithins on parameters of defence against infection in weaned pigs; 2^nd communication: Influence of soy- or egg lecithin An experiment was conducted to investigate the effect of different phospholipid profiles on parameters of defence against infection. 30 weaned piglets were fed for 41 days with experimental diets containing soy lecithin (6%), egg lecithin (6%) or isoenergetic 13.8% corn starch (control) in the diet. Parameters of defence against infection were tested on experimental days 0, 11, 18, 25, 41. In comparison to the control group 6% of soy lecithin and 6% of egg lecithin in the diet significantly increased Nitroblue Tetrazolium-reductive potential on days 18 and 41, lysozyme concentrations on day 18 and granulocyte numbers on day 18 (nonspecific immunity). Feeding 6% soy- or egg lecithin compared to 13.8% starch decreased IgG concentrations and lymphocyte numbers (specific immunity). Most piglets fed diet containing egg lecithin caused diarrhea up to day 16 compared to the other experimental groups.