Unified study of glass and jamming rheology in soft particle systems

We explore numerically the shear rheology of soft repulsive particles at large volume fraction. The interplay between viscous dissipation and thermal motion results in multiple rheological regimes encompassing Newtonian, shear-thinning and yield stress regimes near the `colloidal' glass transition when thermal fluctuations are important, crossing over to qualitatively similar regimes near the `jamming' transition when dissipation dominates. In the crossover regime, glass and jamming sectors coexist and give complex flow curves. Although glass and jamming limits are characterized by similar macroscopic flow curves, we show that they occur over distinct time and stress scales and correspond to distinct microscopic dynamics. We propose a simple rheological model describing the glass to jamming crossover in the flow curves, and discuss the experimental implications of our results.Comment: 5 pages, 3 figs; v2 accepted to publication to Phys. Rev. Let

Chondrocranial Morphology of Leptodactylus Larvae (Leptodactylidae: Leptodactylinae): Its Utility in Phylogenetic Reconstruction

Chondrocranial morphology of leptodactylid frogs is scarcely known and has not been completely described for any species of Leptodactylus. We describe the diversity of chondrocranial morphology in the genus Leptodactylus based on the analysis of 22 species, representing the four species groups: the fuscus Group, ocellatus Group, melanonotus Group, and pentadactylus Group. Furthermore, 26 characters are identified and used in a phylogenetic analysis. The phylogenetic analysis using Physalaemus, Crossodactylus, and Hylodes as outgroups suggests two monophyletic clades within Leptodactylus: the melanonotus-ocellatus clade and the pentadactylusfuscus clade. However, it does not support the monophyly of the species groups as currently recognized and it suggests a paraphyletic Leptodactylus. Enforcing the monophyly of the ingroup, i.e., Leptodactylus, results in the same major two clades of Leptodactylus. Leptodactylus riveroi, a taxon previously unassigned to any species group, appears most closely related to the melanonotus-ocellatus clade based on chondrocranial characteristics

Towards a unified theory of intensional logic programming

AbstractIntensional Logic Programming is a new form of logic programming based on intensional logic and possible worlds semantics. Intensional logic allows us to use logic programming to specify nonterminating computations and to capture the dynamic aspects of certain problems in a natural and problem-oriented style. The meanings of formulas of an intensional first-order language are given according to intensional interpretations and to elements of a set of possible worlds. Neighborhood semantics is employed as an abstract formulation of the denotations of intensional operators. Then we investigate general properties of intensional operators such as universality, monotonicity, finitariness and conjunctivity. These properties are used as constraints on intensional logic programming systems. The model-theoretic and fixpoint semantics of intensional logic programs are developed in terms of least (minimum) intensional Herbrand models. We show in particular that our results apply to a number of intensional logic programming languages such as Chronolog proposed by Wadge and Templog by Abadi and Manna. We consider some elementary extensions to the theory and show that intensional logic program clauses can be used to define new intensional operators. Intensional logic programs with intensional operator definitions are regarded as metatheories

Blackwell Publishing Ltd. Chondrocranial, hyobranchial and internal oral morphology in larvae of the basal bufonid genus Melanophryniscus (Amphibia: Anura)

Melanophryniscus is a genus of small toads inhabiting the southern portion of South America. This genus is considered basal within the family Bufonidae. Data on larval chondrocranial morphology do not exist for the genus and larval internal oral anatomy has only been described for a single species. Here, we describe chondrocranial and internal oral morphology in Melanophryniscus montevidensis, M. orejasmirandai and M. sanmartini. Chondrocranial morphology is similar among the species examined. Comparisons with other bufonids and with outgroup taxa suggest that the following chondrocranial characters may represent synapomorphies for the Bufonidae: free (or absent) ceratobranchial IV, a reduced or absent larval crista parotica, the lack of a larval otic process, and late development of thin, poorly chondrified orbital cartilages. The presence of an elongated processus anterior dorsalis of the suprarostral alae and the absence of a chondrified commissura quadratoorbitalis appear to be unique in Melanophryniscus among bufonids. Internal oral anatomy is conserved in Melanophryniscus, and among bufonids in general

Molecular Targeting of Carbonic Anhydrase IX in Mice with Hypoxic HT29 Colorectal Tumor Xenografts

Background: Carbonic anhydrase IX (CAIX) is a membrane spanning protein involved in the enzymatic regulation of tumor acid-base balance. CAIX has been shown to be elevated in a number of hypoxic tumor types. The purpose of this study was to determine the efficiency of intact and IgG fragments of cG250 to target CAIX in vivo in a hypoxic tumor model. Methodology/Principal Findings: Conventional biodistribution studies were performed with 111 In-DO3A-cG250, 111 In-DO3A-F(ab’)2-cG250 and 111 In-DO3A-Fab-cG250. Additional ex vivo analysis of the tumor was performed with markers for tumor hypoxia, blood perfusion and endogenous CAIX expression. All four data sets were digitally correlated to determine the optimal agent for determining hypoxia in a HT29 colon cancer xenograft. The HT29 human colorectal tumor xenografts show strong CAIX expression in hypoxic areas of poor blood perfusion. The intact IgG had an initial high focal uptake at the periphery of these hypoxic regions and penetration into the areas of highest CAIX expression over the 7-day study period. The lower molecular weight antibody fragments had a faster uptake into areas of high CAIX expression, but had a much lower absolute uptake at the optimal imaging times. Conclusions/Significance: For the clinical detection of hypoxia induced CAIX using cG250 antibody based agents, imagin

Promoting Bicycle Commuter Safety, Research Report 11-08

We present an overview of the risks associated with cycling to emphasize the need for safety. We focus on the application of frameworks from social psychology to education, one of the 5 Es—engineering, education, enforcement, encouragement, and evaluation. We use the structure of the 5 Es to organize information with particular attention to engineering and education in the literature review. Engineering is essential because the infrastructure is vital to protecting cyclists. Education is emphasized since the central focus of the report is safety

Supernova Enrichment of Dwarf Spheroidal Galaxies

(Abridged) Many dwarf galaxies exhibit sub-Solar metallicities, with some star-to-star variation, despite often containing multiple generations of stars. The total metal content in these systems is much less than expected from the heavy element production of massive stars in each episode of star formation. Such a deficiency implies that a substantial fraction of the enriched material has been lost from these small galaxies. Mass ejection from dwarf galaxies may have important consequences for the evolution of the intergalactic medium and for the evolution of massive galaxies, which themselves may have formed via the merger of smaller systems. We report here the results of three-dimensional simulations of the evolution of supernova-enriched gas within dwarf spheroidal galaxies (dSph's), with the aim of determining the retention efficiency of supernova ejecta. We consider two galaxy models, selected to represent opposite ends of the dSph sequence. For each model galaxy we investigate a number of scenarios, ranging from a single supernova in smooth gas distributions to more complex multiple supernovae in highly disturbed gas distributions. The results of these investigations suggest that, for low star-formation efficiencies, it is difficult to completely expel the enriched material from the galaxy. Most of the enriched gas is, however, lost from the core of the galaxy following multiple supernovae, especially if the interstellar medium is already highly disturbed by processes such as photo-ionization and stellar winds. If subsequent star formation occurs predominantly within the core where most of the residual gas is concentrated, then these results could explain the poor self-enrichment efficiency observed in dwarf galaxies.Comment: 29 pages, 10 figures, to appear in Astrophysical Journa

Insecticide-treated net use before and after mass distribution in a fishing community along Lake Victoria, Kenya: successes and unavoidable pitfalls

Abstract Background Insecticide-treated nets (ITNs) have proven instrumental in the successful reduction of malaria incidence in holoendemic regions during the past decade. As distribution of ITNs throughout sub-Saharan Africa (SSA) is being scaled up, maintaining maximal levels of coverage will be necessary to sustain current gains. The effectiveness of mass distribution of ITNs, requires careful analysis of successes and failures if impacts are to be sustained over the long term. Methods Mass distribution of ITNs to a rural Kenyan community along Lake Victoria was performed in early 2011. Surveyors collected data on ITN use both before and one year following this distribution. At both times, household representatives were asked to provide a complete accounting of ITNs within the dwelling, the location of each net, and the ages and genders of each person who slept under that net the previous night. Other data on household material possessions, education levels and occupations were recorded. Information on malaria preventative factors such as ceiling nets and indoor residual spraying was noted. Basic information on malaria knowledge and health-seeking behaviours was also collected. Patterns of ITN use before and one year following net distribution were compared using spatial and multi-variable statistical methods. Associations of ITN use with various individual, household, demographic and malaria related factors were tested using logistic regression. Results After infancy (<1 year), ITN use sharply declined until the late teenage years then began to rise again, plateauing at 30 years of age. Males were less likely to use ITNs than females. Prior to distribution, socio-economic factors such as parental education and occupation were associated with ITN use. Following distribution, ITN use was similar across social groups. Household factors such as availability of nets and sleeping arrangements still reduced consistent net use, however. Conclusions Comprehensive, direct-to-household, mass distribution of ITNs was effective in rapidly scaling up coverage, with use being maintained at a high level at least one year following the intervention. Free distribution of ITNs through direct-to-household distribution method can eliminate important constraints in determining consistent ITN use, thus enhancing the sustainability of effective intervention campaigns.http://deepblue.lib.umich.edu/bitstream/2027.42/111296/1/12936_2014_Article_3656.pd

Inferred summer precipitation for southern Ontario back to AD 610, as reconstructed from ring widths of Thuja occidentalis

We present a network of seven ring-width chronologies of eastern white-cedar (Thuja occidentalis L.) from the Niagara Escarpment in southern Ontario, Canada. Using principal component regression, a 350-year June-July precipitation reconstruction (SOR) is developed for the region. Prior to the 20th century, the SOR series shows reasonable coherence, particularly at the decadal scale, with an independent tree-ring-based reconstruction of the Palmer drought severity index (PDSI) for roughly the same region. A weakening of the tree-growth – climate relationship in recent decades results in a regression model explaining 21% of the variance in the original climate series when the recent data are used for calibration. We therefore compromise with a model, calibrated for the period 1900–1960, which explains 33% of the variance. The model, while not terribly strong, does pass verification tests, indicating some degree of predictive skill. The longest chronology in our network, the 2787-year Flowerpot Island (FLOW) chronology, also exhibits common variability with the PDSI reconstruction, particularly on decadal and longer time scales and was used to infer hydroclimatic conditions back to AD 610. The combined information of the SOR, PDSI, and FLOW series suggests that dry conditions existed for the periods 1700–1725, 1750–1800, and 1840–1900, and wet conditions for the periods 1675–1700, 1730–1750, and 1810–1840. Over longer time scales, the FLOW chronology shows that summer precipitation was particularly variable during the 7th, 9th, 13th, and 16th centuries