Discovering bipartite substructure in directed networks

Bipartivity is an important network concept that can be applied to nodes, edges and communities. Here we focus on directed networks and look for subnetworks made up of two distinct groups of nodes, connected by “one-way” links. We show that a spectral approach can be used to find hidden substructure of this form. Theoretical support is given for the idealised case where there is limited overlap between subnetworks. Numerical experiments show that the approach is robust to spurious and missing edges. A key application of this work is in the analysis of high-throughput gene expression data, and we give an example where a biologically meaningful directed bipartite subnetwork is found from a cancer microarray dataset

Controllable forms for stabilising pole assignment design of generalised bilinear systems

Bilinear structures are able to represent nonlinear phenomena more accurately than linear models, and thereby help to extend the range of satisfactory control performance. However, closed loop characteristics are typically designed by simulation and stability is not guaranteed. In this reported work, it is shown how bilinear systems are a special case of the more general state dependent parameter (SDP) model, which can subsequently be utilised to design stabilising feedback controllers using a special form of nonlinear pole assignment. To establish the link, however, an important generalisation of the SDP pole assignment method is developed

Testing Bekenstein's Relativistic MOND gravity with Lensing Data

We propose to use multiple-imaged gravitational lenses to set limits on gravity theories without dark matter, specificly TeVeS (Bekenstein 2004), a theory which is consistent with fundamental relativistic principles and the phenomenology of MOdified Newtonian Dynamics (MOND) theory. After setting the framework for lensing and cosmology, we derive analytically the deflection angle for the point lens and the Hernquist galaxy profile, and fit galaxy-quasar lenses in the CASTLES sample. We do this with three methods, fitting the observed Einstein ring sizes, the image positions, or the flux ratios. In all cases we consistently find that stars in galaxies in MOND/TeVeS provide adequate lensing. Bekenstein's toy $\mu$ function provides more efficient lensing than the standard MOND $\mu$ function. But for a handful of lenses [indicated in Table 2,3, fig 16] a good fit would require a lens mass orders of magnitude larger/smaller than the stellar mass derived from luminosity unless the modification function $\mu$ and modification scale $a_0$ for the universal gravity were allowed to be very different from what spiral galaxy rotation curves normally imply. We discuss the limitation of present data and summarize constraints on the MOND $\mu$ function. We also show that the simplest TeVeS "minimal-matter" cosmology, a baryonic universe with a cosmological constant, can fit the distance-redshift relation from the supernova data, but underpredicts the sound horizon size at the last scattering. We conclude that lensing is a promising approach to differentiate laws of gravity (see also astro-ph/0512425).Comment: reduced to 17p, 16 figs, discussed cosmology and constraints on mu-function, MNRAS accepte

Investigation of the influence of a step change in surface roughness on turbulent heat transfer

The use is studied of smooth heat flux gages on the otherwise very rough SSME fuel pump turbine blades. To gain insights into behavior of such installations, fluid mechanics and heat transfer data were collected and are reported for a turbulent boundary layer over a surface with a step change from a rough surface to a smooth surface. The first 0.9 m length of the flat plate test surface was roughened with 1.27 mm hemispheres in a staggered, uniform array spaced 2 base diameters apart. The remaining 1.5 m length was smooth. The effect of the alignment of the smooth surface with respect to the rough surface was also studied by conducting experiments with the smooth surface aligned with the bases or alternatively with the crests of the roughness elements. Stanton number distributions, skin friction distributions, and boundary layer profiles of temperature and velocity are reported and are compared to previous data for both all rough and all smooth wall cases. The experiments show that the step change from rough to smooth has a dramatic effect on the convective heat transfer. It is concluded that use of smooth heat flux gages on otherwise rough surfaces could cause large errors

Association of molecules using a resonantly modulated magnetic field

We study the process of associating molecules from atomic gases using a magnetic field modulation that is resonant with the molecular binding energy. We show that maximal conversion is obtained by optimising the amplitude and frequency of the modulation for the particular temperature and density of the gas. For small modulation amplitudes, resonant coupling of an unbound atom pair to a molecule occurs at a modulation frequency corresponding to the sum of the molecular binding energy and the relative kinetic energy of the atom pair. An atom pair with an off-resonant energy has a probability of association which oscillates with a frequency and time-varying amplitude which are primarily dependent on its detuning. Increasing the amplitude of the modulation tends to result in less energetic atom pairs being resonantly coupled to the molecular state, and also alters the dynamics of the transfer from continuum states with off-resonant energies. This leads to maxima and minima in the total conversion from the gas as a function of the modulation amplitude. Increasing the temperature of the gas leads to an increase in the modulation frequency providing the best fit to the thermal distribution, and weakens the resonant frequency dependence of the conversion. Mean-field effects can alter the optimal modulation frequency and lead to the excitation of higher modes. Our simulations predict that resonant association can be effective for binding energies of order $h \times 1$ MHz.Comment: 8 pages latex, figures revised, references updated and typos correcte

Emergent Analogical Reasoning in Large Language Models

The recent advent of large language models has reinvigorated debate over whether human cognitive capacities might emerge in such generic models given sufficient training data. Of particular interest is the ability of these models to reason about novel problems zero-shot, without any direct training. In human cognition, this capacity is closely tied to an ability to reason by analogy. Here, we performed a direct comparison between human reasoners and a large language model (the text-davinci-003 variant of GPT-3) on a range of analogical tasks, including a novel text-based matrix reasoning task closely modeled on Raven's Progressive Matrices. We found that GPT-3 displayed a surprisingly strong capacity for abstract pattern induction, matching or even surpassing human capabilities in most settings. Our results indicate that large language models such as GPT-3 have acquired an emergent ability to find zero-shot solutions to a broad range of analogy problems

Hybrid squeezing of solitonic resonant radiation in photonic crystal fibers

We report on the existence of a novel kind of squeezing in photonic crystal fibers which is conceptually intermediate between the four-wave mixing induced squeezing, in which all the participant waves are monochromatic waves, and the self-phase modulation induced squeezing for a single pulse in a coherent state. This hybrid squeezing occurs when an arbitrary short soliton emits quasi-monochromatic resonant radiation near a zero group velocity dispersion point of the fiber. Photons around the resonant frequency become strongly correlated due to the presence of the classical soliton, and a reduction of the quantum noise below the shot noise level is predicted.Comment: 5 pages, 2 figure

Intranasal immunisation with recombinant adenovirus vaccines protects against a lethal 2 challenge with pneumonia virus of mice

Pneumonia virus of mice (PVM) infection of BALB/c mice induces bronchiolitis leading to a fatal pneumonia in a dose-dependent manner, closely paralleling the development of severe disease during human respiratory syncytial virus infection in man, and is thus a recognised model in which to study the pathogenesis of pneumoviruses. This model system was used to investigate delivery of the internal structural proteins of PVM as a potential vaccination strategy to protect against pneumovirus disease. Replication-deficient recombinant human adenovirus serotype 5 (rAd5) vectors were constructed that expressed the M or N gene of PVM pathogenic strain J3666. Intranasal delivery of these rAd5 vectors gave protection against a lethal challenge dose of PVM in three different mouse strains, and protection lasted for at least 20 weeks post-immunisation. Whilst the PVM-specific antibody response isuch animals was weak and inconsistent, rAd5N primed a strong PVM-specific CD8+ T cell response and, to a lesser extent, a CD4+ T cell response. These findings suggest that protection induced by rAd5N was mediated by T-cells rather than serum antibody

Geological and 40Ar/39Ar geochronological constraints on the timing of quartz vein formation in Meguma Group lode-gold deposits, Nova Scotia

The results of geological and 40Ar/39Ar geochronological investigations of several gold districts hosted by the Meguma Group are presented. Observations at both the macro- (deposit to ore zone) and micro- (hand sample to thin section) scale indicate that quartz vein formation followed major Acadian folding and metamorphism (ca. 400 ±10 Ma) and was broadly coincident with mafic-felsic magmatism at ca. 370 Ma. 40Ar/39Ar analyses of vein-fill mica and amphibole from the Beaver Dam, Moose River, Fifteen Mile Stream, Upper Seal Harbour and Caribou deposits indicate ages of ca. 380 Ma to ca. 362 Ma. The age data are interpreted to reflect discrete hydrothermal events with rapid cooling following crystallization of vein constituents. The age data do not reflect either variable amounts of resetting by later granitic intrusions or diachronous cooling. Genetic models that interpret the generation of the auriferous quartz veins as either before or during major Acadian folding are considered to be inconsistent with the present results. Instead, a model is favored that interprets quartz vein formation in the context of continued transpression of the Meguma Terrane following regional folding and metamorphism. RÉSUMÉ On présente les résultats d'études géologiques et géochronologiques [40Ar/39Ar] effectuées dans plusieurs districts aurifères au sein du Groupe de Meguma. Des observations tant macroscopiques (du gite à la zone de minéral) que microscopiques (de l'échantillon à la lame mince) indiquent que la formation des veines de quartz suivit un métamorphisme et un plissement majeurs acadiens (env. 400 ± 10 Ma) et coiincida d'une facon générale avec unmagmatisme mafique à felsique vers 370 Ma. Des analyses 40Ar/39Ar effectuées sur des micas et des amphiboles de remplissages de veine provenant des gites de Beaver Dam, Moose River, Fifteen Mile Stream, Upper Seal Harbour et Caribou révèlent des âges aux environs de 380 à 362 Ma. On interprète ces données d 'âge comme le reflet d'épisodes hydrothèrmaux distincts avec un refroidissement rapide suite à la cristallisation des constituants filoniens. Ces données ne reflètent ni un degré variable de remise à ziro par des intrusions granitiques ultérieures, ni un refroidissement diachrone. On considere que les modèles genetiques interprétant la formation des veines de quartz auriferes comme precedent ou ayant eu lieu pendant le plissement majeur acadien, sont en contradiction avec les resultats actuels. En leur lieu, on favorise un modèle qui interprète la formation des veines de quartz dans le contexte d'une transpression continue de la Lanière de Méguma à la suite d'un plissement et d'un métamorphisme régionaux. [Traduit par le journal