Towards an understanding of hole superconductivity

From the very beginning K. Alex M\"uller emphasized that the materials he and George Bednorz discovered in 1986 were $hole$ superconductors. Here I would like to share with him and others what I believe to be $the$ key reason for why high $T_c$ cuprates as well as all other superconductors are hole superconductors, which I only came to understand a few months ago. This paper is dedicated to Alex M\"uller on the occasion of his 90th birthday.Comment: Dedicated to Alex M\"uller on the Occasion of his 90th Birthday. arXiv admin note: text overlap with arXiv:1703.0977

Isolation of 10 cyclosporine metabolites from human bile

Ten metabolites of cyclosporine were isolated from the ethyl ether extract of bile from four liver transplant patients receiving cyclosporine. Two of the metabolites were unique and previously unidentified. Liquid-liquid partitioning into diethyl ether with subsequent defatting with n-hexane was used for the initial extraction form bile. Separation of the individual metabolites (A-J) was performed using a Sephadex LH-20 column and a gradient high performance liquid chromatographic method. The molecular weights of the isolated metabolites were determined by fast atom bombardment/mass spectrometry. Gas chromatography with mass spectrometic amino acid analysis was also used to identify the amino acid composition and the hydroxylation position of metabolites A, B, C, D, and G. Proton nuclear magnetic resonance spectra were utilized to disinguish the chemical shifts of N-CH3 singlets and NH doublets of metabolites A, B, C, and D. Metabolites A, E, F, H, I, and J were reported previously in human urine and animal bile. Metabolites C and D are dihydroxylated compounds which cannot be clearly described as previously isolated compounds. Metabolites B and G are novel metabolites with a mass fragment which corresponded to a loss of 131 Da from the protonated molecular ion (MH+) in the fast atom bombardment/mass spectrometry, suggesting that the double bond in amino acid 1 has been modified. Metabolites B and G were primarily isolated from the bile of one of the liver transplant patients which contained abnormally high concentrations of these two metabolites. The method described is an efficient procedure for isolating milligram quantities of the major metabolites with greater than 95% purity

Busy Beaver Scores and Alphabet Size

We investigate the Busy Beaver Game introduced by Rado (1962) generalized to non-binary alphabets. Harland (2016) conjectured that activity (number of steps) and productivity (number of non-blank symbols) of candidate machines grow as the alphabet size increases. We prove this conjecture for any alphabet size under the condition that the number of states is sufficiently large. For the measure activity we show that increasing the alphabet size from two to three allows an increase. By a classical construction it is even possible to obtain a two-state machine increasing activity and productivity of any machine if we allow an alphabet size depending on the number of states of the original machine. We also show that an increase of the alphabet by a factor of three admits an increase of activity

Slow Passage through a Saddle-Node Bifurcation in Discrete Dynamical Systems

We study a discrete non-autonomous system whose autonomous counterpart (with the frozen bifurcation parameter) admits a saddle-node bifurcation, and in which the bifurcation parameter slowly changes in time and is characterized by a sweep rate constant $\epsilon$. The discrete system is more appropriate for modeling realistic systems since only time series data is available. We show that in contrast to its autonomous counterpart, when the time mesh size $\Delta t$ is less than the order $O(\epsilon)$, there is a bifurcation delay as the bifurcation time-varying parameter is varied through the bifurcation point, and the delay is proportional to the two-thirds power of the sweep rate constant $\epsilon$. This bifurcation delay is significant in various realistic systems since it allows one to take necessary action promptly before a sudden collapse or shift to different states. On the other hand, when the time mesh size $\Delta t$ is larger than the order $o(\epsilon)$, the dynamical behavior of the solution is dramatically changed before the bifurcation point. This behavior is not observed in the autonomous counterpart. Therefore, the dynamical behavior of the system strongly depends on the time mesh size. Finally. due to the very discrete feature of the system, there are no efficient tools for the analytical study of the system. Our approach is elementary and analytical

Tracking advanced persistent threats in critical infrastructures through opinion dynamics

Advanced persistent threats pose a serious issue for modern industrial environments, due to their targeted and complex attack vectors that are difficult to detect. This is especially severe in critical infrastructures that are accelerating the integration of IT technologies. It is then essential to further develop effective monitoring and response systems that ensure the continuity of business to face the arising set of cyber-security threats. In this paper, we study the practical applicability of a novel technique based on opinion dynamics, that permits to trace the attack throughout all its stages along the network by correlating different anomalies measured over time, thereby taking the persistence of threats and the criticality of resources into consideration. The resulting information is of essential importance to monitor the overall health of the control system and cor- respondingly deploy accurate response procedures. Advanced Persistent Threat Detection Traceability Opinion Dynamics.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

The evolution of circumstellar discs in the galactic centre: an application to the G-clouds

The Galactic Centre is known to have undergone a recent star formation episode a few Myr ago, which likely produced many T Tauri stars hosting circumstellar discs. It has been suggested that these discs may be the compact and dusty ionized sources identified as ‘G-clouds’. Given the Galactic Centre’s hostile environment, we study the possible evolutionary pathways these discs experience. We compute new external photoevaporation models applicable to discs in the Galactic Centre that account for the subsonic launching of the wind and absorption of UV photons by dust. Using evolutionary disc calculations, we find that photoevaporation’s rapid truncation of the disc causes them to accrete onto the central star rapidly. Ultimately, an accreting circumstellar disc has a lifetime ≲ 1 Myr, which would fail to live long enough to explain the G-clouds. However, we identify a new evolutionary pathway for circumstellar discs in the Galactic Centre. Removal of disc material by photoevaporation prevents the young star from spinning down due to magnetic braking, ultimately causing the rapidly spinning young star to torque the disc into a ‘decretion disc’ state which prevents accretion. At the same time, any planetary companion in the disc will trap dust outside its orbit, shutting down photoevaporation. The disc can survive for up to ∼10 Myr in this state. Encounters with other stars are likely to remove the planet on Myr time-scales, causing photoevaporation to restart, giving rise to a G-cloud signature. A giant planet fraction of ∼10 per cent can explain the number of observed G-clouds

Certainly Unsupervisable States

This paper proposes an abstraction method for compositional synthesis. Synthesis is a method to automatically compute a control program or supervisor that restricts the behaviour of a given system to ensure safety and liveness. Compositional synthesis uses repeated abstraction and simplification to combat the state-space explosion problem for large systems. The abstraction method proposed in this paper finds and removes the so-called certainly unsupervisable states. By removing these states at an early stage, the final state space can be reduced substantially. The paper describes an algorithm with cubic time complexity to compute the largest possible set of removable states. A practical example demonstrates the feasibility of the method to solve real-world problems

Sex-specific effects of nutritional supplements in infants born early or small: protocol for an individual participant data meta-analysis (ESSENCE IPD-MA).

INTRODUCTION: Preterm and small for gestational age (SGA) infants are at increased risk of poor growth, disability and delayed development. While growing up they are also at increased risk of obesity, diabetes and later heart disease. The risk of such adverse outcomes may be altered by how preterm and SGA infants are fed after birth. Faltering postnatal growth is common due to failure to achieve recommended high energy and protein intakes, and thus preterm and SGA infants are often provided with supplemental nutrition soon after birth. Enhanced nutrition has been associated with improved early growth and better cognitive development. However, limited evidence suggests that faster growth may increase the risk for later adiposity, metabolic and cardiovascular disease, and that such risks may differ between girls and boys. METHODS AND ANALYSIS: We will search Ovid MEDLINE, Embase, Cochrane CENTRAL, Cochrane Database of Systematic Reviews, controlled-trials.com, ClinicalTrials.gov and anzctr.org.au for randomised trials that studied the effects of macronutrient supplements for preterm and SGA infants on (i) developmental and metabolic and (ii) growth outcomes after hospital discharge. The outcomes will be (i) cognitive impairment and metabolic risk (co-primary) and (ii) body mass index. Individual participant data (IPD) from all available trials will be included using an intention-to-treat approach. A one-stage procedure for IPD meta-analysis (MA) will be used, accounting for clustering of participants within studies. Exploratory subgroup analyses will further investigate sources of heterogeneity, including sex and size of infants, different timing, duration and type of supplements. ETHICS AND DISSEMINATION: This IPD-MA is approved by the University of Auckland Human Participants Ethics Committee (reference number: 019874). Individual studies have approval from relevant local ethics committees. Results will be disseminated in a peer-reviewed journal and presented at international conferences. PROSPERO REGISTRATION NUMBER: CRD42017072683