110 research outputs found

    Free-algebra functors from a coalgebraic perspective

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    Given a set Σ\Sigma of equations, the free-algebra functor FΣF_{\Sigma} associates to each set XX of variables the free algebra FΣ(X)F_{\Sigma}(X) over XX. Extending the notion of \emph{derivative} Σ\Sigma' for an arbitrary set Σ\Sigma of equations, originally defined by Dent, Kearnes, and Szendrei, we show that FΣF_\Sigma preserves preimages if and only if ΣΣ\Sigma \vdash \Sigma', i.e. Σ\Sigma derives its derivative Σ\Sigma'. If FΣF_\Sigma weakly preserves kernel pairs, then every equation p(x,x,y)=q(x,y,y)p(x,x,y)=q(x,y,y) gives rise to a term s(x,y,z,u)s(x,y,z,u) such that p(x,y,z)=s(x,y,z,z)p(x,y,z)=s(x,y,z,z) and q(x,y,z)=s(x,x,y,z)q(x,y,z)=s(x,x,y,z). In this case n-permutable varieties must already be permutable, i.e. Mal'cev. Conversely, if Σ\Sigma defines a Mal'cev variety, then FΣF_\Sigma weakly preserves kernel pairs. As a tool, we prove that arbitrary SetSet-endofunctors FF weakly preserve kernel pairs if and only if they weakly preserve pullbacks of epis

    Music motivation depends on what to motivate: research review of Gumm’s music teaching and conducting models

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    The history and philosophy of music education are traced with varied efforts to hone, enhance, and shift a strong tradition of performance-based instruction. The purpose of this study is to summarize the research of Gumm’s empirical models of eight music teaching and six conducting approaches and their application in the profession across three decades toward varied philosophical aims. Each approach coordinates a distinct set of instructional and motivational behaviors toward a particular learning effect or outcome. Different balances of approaches reveal broader aims, such as performance, comprehensive musicianship, cooperative, discovery, and affective learning, or even basic on-task behavior. Broader yet are two overarching aims found in common to both music teaching and conducting—to control or release. Controlling music teaching asserts correct on-task behavior through clear task directions and corrective feedback, motivates attention to task nonverbally, efficiently fills time with active tasks, and clarifies and affirms positive learning. In contrast, cooperative group leadership releases interdependent learning, questioning fosters music concept learning, imagery and movement release artistry, and discussing unique perspectives releases independent ideas and feelings. In conducting, precise gestures control accurate timing, signals and alerts motivate attention, and mimicry of musician exertions controls physical tone production; whereas shaping of phrases and score markings release musical expression, psychosocially familiarized gestures foster interdependence, and tension-easing gestures release freer independent tone production. Control-oriented teaching is most prevalent across the field, yet links to greater burnout and appeals to accommodating students motivated by effort and ability more than students motivated by social and affective enjoyment of music. In conducting, music-oriented precision and expression are more prevalent than musician-oriented approaches. Releasing approaches are more prevalent in Western than Eastern culture, upper levels, early rehearsals well before concerts, smaller ensembles, competitive ensembles, and teachers and conductors with greater experience or varied movement training. Conclusive implications are that the key to motivation is to draw attention to specific and intentional forms of learning, and that whatever is motivated to attention also motivates a particular philosophy of music education. Future research is suggested in general music and ethnic, folk, popular, community, and professional music ensembles

    The Identification of Conductor-Distinguished Functions of Conducting

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    The purpose of the present study was to identify whether conductors distinguish functions of conducting similarly to functions implied in previous research. A sample of 84 conductors with a full range of experience levels (M = 9.8) and of a full range of large ensemble types and ensemble age levels rated how much they pay attention to 82 research-derived conducting considerations as they conduct. The subject-to-variable ratio was smaller than advisable for factor analysis, yet the representatively diverse sample provided reliable ratings (a = .95) and factor results that corroborate traditional music-related functions—Mechanical Precision Function and Expressive Function—and nontraditional musician-oriented functions—Motivational Function, Physical Technique Function, Psychosocial Function, and Unrestrained Tone Function. Functions were discovered to divide based on opposing aims to control precise mechanics, musician attention, and musician energy and range of motion versus to release expression, tension and control of tone and tempo, and control of musicians in favor of sharing control with musicians. The six functions bring new clarity to the trends of conducting research and establish a potential new standard for conducting. Future research is needed to evaluate construct validity and determine reliable and valid measures of these six conducting functions

    Bisimulation of Labeled State-to-Function Transition Systems of Stochastic Process Languages

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    Labeled state-to-function transition systems, FuTS for short, admit multiple transition schemes from states to functions of finite support over general semirings. As such they constitute a convenient modeling instrument to deal with stochastic process languages. In this paper, the notion of bisimulation induced by a FuTS is proposed and a correspondence result is proven stating that FuTS-bisimulation coincides with the behavioral equivalence of the associated functor. As generic examples, the concrete existing equivalences for the core of the process algebras ACP, PEPA and IMC are related to the bisimulation of specific FuTS, providing via the correspondence result coalgebraic justification of the equivalences of these calculi.Comment: In Proceedings ACCAT 2012, arXiv:1208.430

    Dissolved noble gases and stable isotopes as tracers of preferential fluid flow along faults in the Lower Rhine Embayment, Germany

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    Groundwater in shallow unconsolidated sedimentary aquifers close to the Bornheim fault in the Lower Rhine Embayment (LRE), Germany, has relatively low δ2H and δ18O values in comparison to regional modern groundwater recharge, and 4He concentrations up to 1.7 × 10−4 cm3 (STP) g–1 ± 2.2 % which is approximately four orders of magnitude higher than expected due to solubility equilibrium with the atmosphere. Groundwater age dating based on estimated in situ production and terrigenic flux of helium provides a groundwater residence time of ∼107 years. Although fluid exchange between the deep basal aquifer system and the upper aquifer layers is generally impeded by confining clay layers and lignite, this study’s geochemical data suggest, for the first time, that deep circulating fluids penetrate shallow aquifers in the locality of fault zones, implying  that sub-vertical fluid flow occurs along faults in the LRE. However, large hydraulic-head gradients observed across many faults suggest that they act as barriers to lateral groundwater flow. Therefore, the geochemical data reported here also substantiate a conduit-barrier model of fault-zone hydrogeology in unconsolidated sedimentary deposits, as well as corroborating the concept that faults in unconsolidated aquifer systems can act as loci for hydraulic connectivity between deep and shallow aquifers. The implications of fluid flow along faults in sedimentary basins worldwide are far reaching and of particular concern for carbon capture and storage (CCS) programmes, impacts of deep shale gas recovery for shallow groundwater aquifers, and nuclear waste storage sites where fault zones could act as potential leakage pathways for hazardous fluids

    Assessing the effectiveness of a three-stage on-farm biobed in treating pesticide contaminated wastewater

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    Agricultural point source pesticide pollution arising from contaminated machinery washings and accidental spillages pose a significant threat to river water and groundwater quality. In this study, we assess the effectiveness of a three-stage on-farm biobed for treating pesticide contaminated waste water from a large (20 km2) commercial arable estate. The facility consisted of an enclosed machinery wash-down unit (stage 1), a 49 m2 lined compost-straw-topsoil biobed (stage 2), and a 200 m2 drainage field with a trickle irrigation system (stage 3). Pesticide concentrations were analysed in water samples collected fortnightly between November 2013 and November 2015 from the biobed input and output sumps and from 20 porous pots buried at 45 cm and 90 cm depth within the drainage field. The results revealed that the biobed removed 68–98% of individual pesticides within the contaminated washings, with mean total pesticide concentrations reducing by 91.6% between the biobed input and output sumps. Drainage field irrigation removed a further 68–99% of individual pesticides, with total mean pesticide concentrations reducing by 98.4% and 97.2% in the 45 cm and 90 cm depth porous pots, respectively. The average total pesticide concentration at 45 cm depth in the drainage field (57 µg L-1) was 760 times lower than the mean concentration recorded in the input sump (43,334 µg L-1). There was no evidence of seasonality in the efficiency of biobed pesticide removal, nor was there evidence of a decline in removal efficiency over the two-year monitoring period. However, higher mean total pesticide concentrations at 90 cm (102 µg L-1) relative to 45 cm (57 µg L-1) depth indicated an accumulation of pesticide residues deeper within the soil profile. Overall, the results presented here demonstrate that a three-stage biobed can successfully reduce pesticide pollution risk from contaminated machinery washings on a commercial farm

    Online fluorescence spectroscopy for the real-time evaluation of the microbial quality of drinking water

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    We assessed the utility of online fluorescence spectroscopy for the real-time evaluation of the microbial quality of untreated drinking water. Online fluorimeters were installed on the raw water intake at four groundwater -derived UK public water supplies alongside existing turbidity sensors that are used to forewarn of the presence of microbial contamination in the water industry. The fluorimeters targeted fluorescent dissolved organic matter (DOM) peaks at excitation/emission wavelengths of 280/365 nm (tryptophan-like fluorescence, TLF) and 280/450 nm (humic-like fluorescence, HLF). Discrete samples were collected for Escherichia coli, total bacterial cell counts by flow cytometry, and laboratory-based fluorescence and absorbance. Both TLF and HLF were strongly correlated with E. coli (r ¼ 0.71e0.77)and total bacterial cell concentrations (r ¼ 0.73e0.76), whereas the correlations between turbidity and E. coli (r ¼ 0.48) and total bacterial cell counts (r ¼ 0.40) were much weaker. No clear TLF peak was observed at the sites and all apparent TLF was considered to be optical bleed-through from the neighbouring HLF peak. Therefore, a HLF fluorimeter alone would be sufficient to evaluate the microbial water quality at these sources. Fluorescent DOM was also influenced by site operations such as pump start-up and the precipitation of cations on the sensor windows. Online fluorescent DOM sensors are a better indicator of the microbial quality of untreated drinking water than turbidity and they have wide-ranging potential applications within the water industry

    Genetic Engineering of Trypanosoma (Dutonella) vivax and In Vitro Differentiation under Axenic Conditions

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    Trypanosoma vivax is one of the most common parasites responsible for animal trypanosomosis, and although this disease is widespread in Africa and Latin America, very few studies have been conducted on the parasite's biology. This is in part due to the fact that no reproducible experimental methods had been developed to maintain the different evolutive forms of this trypanosome under laboratory conditions. Appropriate protocols were developed in the 1990s for the axenic maintenance of three major animal Trypanosoma species: T. b. brucei, T. congolense and T. vivax. These pioneer studies rapidly led to the successful genetic manipulation of T. b. brucei and T. congolense. Advances were made in the understanding of these parasites' biology and virulence, and new drug targets were identified. By contrast, challenging in vitro conditions have been developed for T. vivax in the past, and this per se has contributed to defer both its genetic manipulation and subsequent gene function studies. Here we report on the optimization of non-infective T. vivax epimastigote axenic cultures and on the process of parasite in vitro differentiation into metacyclic infective forms. We have also constructed the first T. vivax specific expression vector that drives constitutive expression of the luciferase reporter gene. This vector was then used to establish and optimize epimastigote transfection. We then developed highly reproducible conditions that can be used to obtain and select stably transfected mutants that continue metacyclogenesis and are infectious in immunocompetent rodents

    Complete Genome Characterisation of a Novel 26th Bluetongue Virus Serotype from Kuwait

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    Bluetongue virus is the “type” species of the genus Orbivirus, family Reoviridae. Twenty four distinct bluetongue virus (BTV) serotypes have been recognized for decades, any of which is thought to be capable of causing “bluetongue” (BT), an insect-borne disease of ruminants. However, two further BTV serotypes, BTV-25 (Toggenburg orbivirus, from Switzerland) and BTV-26 (from Kuwait) have recently been identified in goats and sheep, respectively. The BTV genome is composed of ten segments of linear dsRNA, encoding 7 virus-structural proteins (VP1 to VP7) and four distinct non-structural (NS) proteins (NS1 to NS4). We report the entire BTV-26 genome sequence (isolate KUW2010/02) and comparisons to other orbiviruses. Highest identity levels were consistently detected with other BTV strains, identifying KUW2010/02 as BTV. The outer-core protein and major BTV serogroup-specific antigen “VP7” showed 98% aa sequence identity with BTV-25, indicating a common ancestry. However, higher level of variation in the nucleotide sequence of Seg-7 (81.2% identity) suggests strong conservation pressures on the protein of these two strains, and that they diverged a long time ago. Comparisons of Seg-2, encoding major outer-capsid component and cell-attachment protein “VP2” identified KUW2010/02 as 26th BTV, within a 12th Seg-2 nucleotype [nucleotype L]. Comparisons of Seg-6, encoding the smaller outer capsid protein VP5, also showed levels of nt/aa variation consistent with identification of KUW2010/02 as BTV-26 (within a 9th Seg-6 nucleotype - nucleotype I). Sequence data for Seg-2 of KUW2010/02 were used to design four sets of oligonucleotide primers for use in BTV-26, type-specific RT-PCR assays. Analyses of other more conserved genome segments placed KUW2010/02 and BTV-25/SWI2008/01 closer to each other than to other “eastern” or “western” BTV strains, but as representatives of two novel and distinct geographic groups (topotypes). Our analyses indicate that all of the BTV genome segments have evolved under strong purifying selection
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