Dissipationless Collapse of Spherical Protogalaxies and the Fundamental Plane

Following on from the numerical work of Capelato, de Carvalho & Carlberg (1995, 1997), where dissipationless merger simulations were shown to reproduce the "Fundamental Plane" (FP) of elliptical galaxies, we investigate whether the end products of pure, spherically symmetric, one-component dissipationless {\it collapses} could also reproduce the FP. Past numerical work on collisionless collapses have addressed important issues on the dynamical/structural characteristics of collapsed equilibrium systems. However, the study of collisionless collapse in the context of the nature of the FP has not been satisfactorily addressed yet. Our aim in this paper is to focus our attention on the resulting collapse of simple one-component spherical models with a range of different initial virial coefficients. We find that the characteristic correlations of the models are compatible with virialized, centrally homologous systems. Our results strengthen the idea that merging may be a fundamental ingredient in forming non-homologous objects.Comment: 9 pages, 4 Postscript figures, Astronomy & Astrophysics in press (2002). Abstract placement correcte

What is the probability of connecting two points ?

The two-terminal reliability, known as the pair connectedness or connectivity function in percolation theory, may actually be expressed as a product of transfer matrices in which the probability of operation of each link and site is exactly taken into account. When link and site probabilities are $p$ and $\rho$, it obeys an asymptotic power-law behavior, for which the scaling factor is the transfer matrix's eigenvalue of largest modulus. The location of the complex zeros of the two-terminal reliability polynomial exhibits structural transitions as $0 \leq \rho \leq 1$.Comment: a few critical polynomials are at the end of the .tex source fil

Interactive Mapping Technologies, Information Literacy, and the Literature/Composition Course

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Dust and gas in luminous infrared galaxies - results from SCUBA observations

We present new data taken at 850 $\mu$m with SCUBA at the JCMT for a sample of 19 luminous infrared galaxies. Fourteen galaxies were detected. We have used these data, together with fluxes at 25, 60 and 100 $\mu$m from IRAS, to model the dust emission. We find that the emission from most galaxies can be described by an optically thin, single temperature dust model with an exponent of the dust extinction coefficient ($k_\lambda \propto \lambda^{-\beta}$) of $\beta \simeq 1.5 - 2$. A lower $\beta\simeq 1$ is required to model the dust emission from two of the galaxies, Arp 220 and NGC 4418. We discuss various possibilities for this difference and conclude that the most likely is a high dust opacity. In addition, we compare the molecular gas mass derived from the dust emission, $M_{dust}$, with the molecular gas mass derived from the CO emission, $M_{CO}$, and find that $M_{CO}$ is on average a factor 3 higher than $M_{dust}$.Comment: 10 pages, 6 figures, latex, with MN-macros, accepted by MNRAS - revised version (changed flux values for some galaxies

The usability of ventilators: a comparative evaluation of use safety and user experience

Setup of the testing facilities at the Clinical Skills and Patient Simulation Center at the University of North Carolina School of Medicine, where the simulator room and observation room can be seen. (TIF 9461 kb

The Large-Scale Atomic and Molecular Gas in the Circinus Galaxy

We have used the ATCA and the SEST to map the large-scale atomic and molecular gas in the nearby Circinus galaxy. The HI mosaic of Circinus exhibits the warps in position angle and inclination revealed in the single-pointing image, both of which appear to settle beyond the inner 30 kpc which was previously imaged. The molecular gas has been mapped in both the CO transitions, where we derive a total molecular gas mass of ~2e9 Mo. Within a radius of 3 kpc, i.e. where CO was clearly detected, the molecular fraction climbs steeply from ~0.7 to unity with proximity to the nucleus. Our HI mosaic gives an atomic gas mass of ~6e9 Mo which is 70% of the fully mapped single dish value. The total neutral gas mass to dynamical mass ratio is therefore 3%, consistent with the SAS3 classification of Circinus. The high (molecular) gas mass fraction found previously, only occurs close to the central ~0.5 kpc and falls to < 10% within and outwith this region, allaying previous concerns regarding the validity of applying the Galactic conversion ratio to Circinus. The rotation curve, as traced by both the HI and CO, exhibits a steep dip at ~1 kpc, the edge of the atomic/molecular ring, within which the star-burst is occurring. We find the atomic and molecular gases to trace different kinematical features and believe that the fastest part of the sub-kpc ring consists overwhelmingly of molecular gas. Beyond the inner kpc, the velocity climbs to settle into a solid body rotation at >10 kpc. Most of the starlight emanates from within this radius and so much of the dynamical mass, which remains climbing to the limit of our data (>50 kpc), must be due to the dark matter halo.Comment: 13 pages, MNRAS in pres

A review of differentiable digital signal processing for music and speech synthesis

The term “differentiable digital signal processing” describes a family of techniques in which loss function gradients are backpropagated through digital signal processors, facilitating their integration into neural networks. This article surveys the literature on differentiable audio signal processing, focusing on its use in music and speech synthesis. We catalogue applications to tasks including music performance rendering, sound matching, and voice transformation, discussing the motivations for and implications of the use of this methodology. This is accompanied by an overview of digital signal processing operations that have been implemented differentiably, which is further supported by a web book containing practical advice on differentiable synthesiser programming (https://intro2ddsp.github.io/). Finally, we highlight open challenges, including optimisation pathologies, robustness to real-world conditions, and design trade-offs, and discuss directions for future research

Short Signature rpoB Gene Sequence to Differentiate Species in Mycobacterium abscessus Group

Mycobacterium abscessus group (MAG) are rapidly growing acid-fast bacteria that consist of three closely related species: M. abscessus (Ma), M. bolletii (Mb), and M. massiliense (Mm). Differentiation of these species can be difficult but is increasingly requested owing to recent infectious outbreaks and their differential drug resistance. We developed a novel and rapid pyrosequencing method using short signature sequences (35 to 45 bp) at a hypervariable site in the rpoB gene to differentiate the three MAG species, along with M. chelonae (Mc), and M. immunogenum (Mi). This method was evaluated using 111 M. chelonae-abscessus complex (MCAC) isolates, including six reference strains. All isolates were successfully differentiated to the species level (69 Ma, four Mb, six Mm, 23 Mc, and nine Mi). The species identifications by this method had 100% agreement with Sanger sequencing as well as an in-silico rpoB typing method. This short signature sequencing (SSS) method is rapid (6 to 7 h), accurately differentiates MAG species, and is useful for informing antimicrobial therapy decision. IMPORTANCE Mycobacterium abscessus group (MAG) are rapidly growing acid-fast bacteria that include three species: M. abscessus, M. massiliense, and M. bolletii. These species are among the leading causes of nontuberculosis mycobacteria infections in humans but difficult to differentiate using commonly used methods. The differences of drug resistance among the species shape the treatment regimens and make it significant for them to be differentiated accurately and quickly. We developed and evaluated a novel short signature sequencing (SSS) method utilizing a gene called rpoB to differentiate the three MAG species, as well as other two species (M. chelonae and M. immunogenum). The identification results had 100% agreement with both the reference method of Sanger sequencing and rpoB typing method via a computer-simulated analysis. This SSS method was accurate and quick (6 to 7 h) for species differentiation, which will benefit patient care. The technology used for this method is affordable and easy to operate

Exploring African lion (Panthera leo) behavioural phenotypes: individual differences and correlations between sociality, boldness and behaviour

Increasing our understanding of personality, at an individual and group level, is crucial to the pre-release assessment of social species within ex situ reintroduction programs. We conducted the first exploration into the personality of a captive-origin pride of African lions (Panthera leo), assessing behavioural variations and consistencies in daily activity, social and hunting behaviour, and boldness. Data were collected via direct observations, while a species-specific protocol for testing boldness, using playbacks, was developed. Differences in sex, age and session time for the activity budget were evaluated using Pearson correlations and repeated-measures ANOVA, while social interactions were analysed using social network analysis. Spearman’s correlations were conducted to assess for associations between boldness scores, activity and sociality. The two boldness tests provided a range of scores per lion, indicating that the test was effective. Correlations and variations in individual behaviour indicated that adults and sub-adults have specific roles within pride behaviour. Correlations between boldness and activity and social behaviours provided information on the role of individuals, allowing investigation into the behaviour of a dominant and a social keystone. Our study indicates that evaluating various aspects of behaviour in conjunction with boldness has the potential to assist the pre-release assessment of a pride within an ex situ reintroduction program.The final publication is available at Springer via http://dx.doi.org/10.1007/s10164-016-0473-

Captive-born collared peccary (Pecari tajacu, Tayassuidae) fails to discriminate between predator and non-predator models

Captive animals may lose the ability to recognize their natural predators, making conservation programs more susceptible to failure if such animals are released into the wild. Collared peccaries are American tayassuids that are vulnerable to local extinction in certain areas, and conservation programs are being conducted. Captive-born peccaries are intended for release into the wild in Minas Gerais state, southeastern Brazil. In this study, we tested the ability of two groups of captive-born collared peccaries to recognize their predators and if they were habituated to humans. Recognition tests were performed using models of predators (canids and felids) and non-predators animals, as well as control objects, such as a plastic chair; a human was also presented to the peccaries, and tested as a separate stimulus. Anti-predator defensive responses such as fleeing and threatening displayswere not observed in response to predator models. Predator detection behaviors both from visual and olfactory cues were displayed, although they were not specifically targeted at predator models. These results indicate that collared peccaries were unable to recognize model predators. Habituation effects, particularly on anti-predator behaviors, were observed both with a 1-h model presentation and across testing days. Behavioral responses to humans did not differ from those to other models. Thus, if these animals were to be released into the wild, they should undergo anti-predator training sessions to enhance their chances of survival