Immunological studies in the domestic fowl

Immunological unresponsiveness to soluble protein antigens has been studied in the domestic fowl using bovine gamma globulin (BGG) and bovine serum albumin (BSA). (SECTION C) Because the serological behaviour of chicken precipitating antibody differs antibody from that of typical mammalian antibody, it was necessary to undertake a preliminary investigation of the chicken anti-BSA and anti-BGG precipitin systems. Both systems were studied by carrying out quantitative precipitin tests and analysing the precipitates for total N and antigen N, Use of 131I-trace-labelled antigen in these tests made it possible to extend the analyses into the region of considerable antigen excess. (i) Neither system exhibited a well defined peak of maximal precipitation but produced a broad plateau over that region, (ii) No true equivalence point could be established for in moderate antibody excess precipitation of antigen was incomplete, (iii) The peculiarities of chicken antisera raise analytical difficulties that are most easily overcome by the use of labelled reagents (iv) A rapid method for the determination of the precipitin content of chicken antisera, using 131I-trace-labelled antigen, is described. It depends upon determination of the percentage of added antigen precipitated at the point of maximal precipitation. (SEDTION D) Although the chicken is a very good producer: of precipitins to native serum, proteins this immunological ability does not seem to extend to chemically altered antigens. In two experiments in which chickens were immunised with 3 different forms of chemically altered B3A only feeble antibody responses were elicited, even after 3 intravenous injections. (SECTION E) To study immunological unresponsiveness to soluble protein antigens both embryos and newly hatched chicks were injected with varying amounts of BGG or B3A, Only with difficulty was unresponsiveness induced, the best results being obtained by giving repeated doses of large amounts (100 mg) of antigen during the first few weeks of life. The results verify the general observations that the duration of unresponsiveness is finite and related to the amount of antigen given in early life to induce it, and that maintenance of the unresponsive state depends upon persistence of antigen. The greater difficulty experienced in making chickens unresponsive to BSA compared to the rabbit and mouse appears to be directly related to the very rapid elimination of BEA by the chicken. The need for further quantitative studies of unresponsiveness is stressed and a method that is; considered suitable for the measurement of a standard degree, of responsiveness is proposed. The chicken is suggested as a useful experimental animal for the type of quantitative study envisaged. (SECTION F) The effect of a cytotoxic drug, 6-mercaptopicrine on precipitin production in the adult fowl, was investigated. This purine analogue has been reported capable of causing a complete specific suppression of antibody response to BSA in the rabbit if given as daily doses during period of primary immunisation, even when the drug was administered at a level three times as great as that known to be effective in rabbits the antibody production of treated birds was equal to that of untreated contols. The failure of 6-MP to suppress antibody formation in the chicken may be due to the particularly vigorous production of precipitins by this species or to a more rapid catabolism and excretion of the drug by the fowl

Volatile hydrocarbons inhibit methanogenic crude oil degradation

Methanogenic degradation of crude oil in subsurface sediments occurs slowly, but without the need for exogenous electron acceptors, is sustained for long periods and has enormous economic and environmental consequences. Here we show that volatile hydrocarbons are inhibitory to methanogenic oil biodegradation by comparing degradation of an artificially weathered crude oil with volatile hydrocarbons removed, with the same oil that was not weathered. Volatile hydrocarbons (nC5-nC10, methylcyclohexane, benzene, toluene, and xylenes) were quantified in the headspace of microcosms. Aliphatic (n-alkanes nC12-nC34) and aromatic hydrocarbons (4-methylbiphenyl, 3-methylbiphenyl, 2-methylnaphthalene, 1-methylnaphthalene) were quantified in the total hydrocarbon fraction extracted from the microcosms. 16S rRNA genes from key microorganisms known to play an important role in methanogenic alkane degradation (Smithella and Methanomicrobiales) were quantified by quantitative PCR. Methane production from degradation of weathered oil in microcosms was rapid (1.1 ± 0.1 μmol CH4/g sediment/day) with stoichiometric yields consistent with degradation of heavier n-alkanes (nC12-nC34). For non-weathered oil, degradation rates in microcosms were significantly lower (0.4 ± 0.3 μmol CH4/g sediment/day). This indicated that volatile hydrocarbons present in the non-weathered oil inhibit, but do not completely halt, methanogenic alkane biodegradation. These findings are significant with respect to rates of biodegradation of crude oils with abundant volatile hydrocarbons in anoxic, sulphate-depleted subsurface environments, such as contaminated marine sediments which have been entrained below the sulfate-reduction zone, as well as crude oil biodegradation in petroleum reservoirs and contaminated aquifers

A resource-advantage perspective on the orchestration of ambidexterity

Strategic resources are key inputs to strategy that can form the basis of superior service performance, yet there is scarce research on the strategic resources used by managers to realise ambidexterity: the simultaneous pursuit of alignment and adaptability. In this article, we draw on a qualitative case study of a leading European airline and examine the resource bundles used by managers in their orchestration of ambidexterity. Adopting a resource-advantage perspective, the study illustrates elements of human, organisational, and informational capital that are mobilised by managers in their incorporation of alignment-oriented and adaptability-oriented activities. By moving beyond a linear association between strategic resources and ambidextrous organisations, we argue that managers' orchestration of ambidexterity is central to how service organisations manage their strategic resources and enhance competitiveness. Overall, we highlight the micro managerial level as an important point of observation to extend current thinking on the ‘how’ of ambidexterity in service organisations

The ambidextrous manager: What role does culture play?

Purpose We know from research that the right context can help managers develop an ambidextrous approach. But just as few of us are naturally ambidextrous, many managers fail to balance conformity and change during strategy implementation. We investigate why. Design/methodology/approach Through a qualitative study of managers of an international airline we examine a series of cultural barriers that constrain managers’ agile decision-making and stop managerial ambidexterity. Findings We identify 6 culturally-ingrained practices that block managerial ambidexterity: Top management’s unwavering emphasis on cost-control when survival hinges on fresh investments; Little or no scanning of the environment for new areas of opportunity; Intensive planning oriented toward efficiency issues; Functional structures characterized by extensive division of labor; Centralized control; Formal hierarchical communication channels. Research implications Managers find it difficult to put into practice new initiatives, particularly when the proposed initiatives counter the underlying cultural world of the organization. We suggest that this dark-side of culture can pose tough barriers for ambidextrous action. Practical implications There is an urgent need for organizations to be aware of the possible misalignments between ambidextrous pursuits and the cultural forces that actually drive action. A deep understanding of their organization’s cultural universe is a crucial first step for managers aspiring to better engage with ambidexterity and outwit and outperform competitors. Originality Different strategic approaches need not be viewed as irreconcilable. If cultural elements don’t block it, managerial ambidexterity can showcase innovative approaches to reconciling trade-offs in strategic decision-making

Implicit Learning: A Demonstration and a Revision of a Novel SRT Paradigm.

CogSci 2013 - 35th annual meeting of the Cognitive Science Society, Berlin, Germany, 31 July - 3 August 2013Yeates, Jones, Wills, Aitken, McLaren and McLaren (2012)devised a serial reaction time (SRT) task that provided evidence for human learning without awareness. Adapting the SRT paradigm usually employed to investigate implicit learning, participants responded to two simple white circle fills on either side of a screen. Instead of these following a sequence that participants were unaware of (e.g. Willingham, Nissen & Bullemer, 1989) this task involved a separate stimulus, which was sometimes predictive of one of the circle fills. A square in the center of the screen would fill with one of eight colors before each circle fill: one of these colors predicted a right circle fill and the other a left on 80% of trials on which those colors occurred. When pressing the key that followed the consistent response trained with these two colors, participants were both faster and more accurate than when responding to either the inconsistent response or control colors. Participants demonstrated a lack of contingency awareness, performing at chance in identifying the predictive colors and on a suitably sensitive prediction task. On reanalyzing this result, this paper shows that it was confounded with a sequential artifact produced by the experimental design itself. Pilot studies demonstrated weak learning of color contingencies when the artifact was removed, thus we sought to improve learning by both increasing the amount of training and placing the predictive color cue on the circle fills. Without the sequential artifact, we can produce the same result, although we concede the effect is less robust than we first indicated. Thus, we are able to reiterate our original conclusion: that this task can demonstrate learning of color contingencies in the absence of awareness and can be used to investigate implicit learning in humans

Implicit Learning: A Demonstration and a Novel SRT Paradigm

CogSci 2012 - 34th annual meeting of the Cognitive Science Society, Sapporo, Japan, 1-4 August 2012Evidence for human learning without awareness of what is learned has been sought in serial reaction time (SRT) tasks in which, unknown to participants, the locations of stimuli follow a particular rule or sequence (Willingham, Nissen & Bullemer, 1989). A number of criticisms have been levelled at such tasks, including a lack of adequate control for sequential effects and a discrepancy in sensitivity between measures of implicit and explicit knowledge about the task (Jones & McLaren, 2009; Shanks & St. John, 1994). In this study we provide a novel, two-choice SRT paradigm whereby the locations of the response stimuli are sometimes predicted by a separate set of stimuli on screen. A color-filled square appears before each stimulus requiring a response, with participants informed this is simply a fixation point to prepare for the next trial. Two out of eight colors are predictive on 80% of trials, and performance on these consistent trials was faster than on the other six colors that were equally likely to result in either of the two possible responses. All these trial types were faster and more accurate than the remaining inconsistent 20% of trials for the predictive colors, which also produce more errors than control colors. A prediction task and interview followed the task, on which participants performed at near (slightly below) chance levels. We suggest that this task is a useful tool for studying associative learning in humans, as it provides reliable effects that appear to demonstrate implicit learning with relatively brief training.This research was supported by an ESRC grant to IPL McLaren and FW Jone

Knowledge-driven mineral potential modelling: applying the Mineral Systems Approach to the west Kimberley, Australia

Regional prospectivity analysis of the west Kimberley has been undertaken using the results of geophysical structural interpretation and the mineral systems approach (MSA) to mineral potential modelling. Ore deposits are small expressions of much larger Earth processes and systems focusing mass and energy flux at multiple scales. The MSA provides a framework within which metal sources, fluid transport mechanisms and traps can be recognised and represented by predictor maps. Predictor maps act as proxies for mineral system processes and include distance to a particular geological feature, locations of rheological and chemical contrast, structural complexity and location of mantle-tapping structures. The approach to mineral potential modelling taken here combines different predictor maps in a knowledge-driven inference framework order to identify likely zones of mineralisation. Nickel-sulphide analysis indicates that the Inglis Fault and Yampi Fold Belt localises areas of increased mineral potential. Carbonate-hosted base metal prospectivity is restricted to regions overlying basement highs in the Lennard Shelf. A buried NW extension of the Oscar Range interpreted from geophysics is identified as a region of high mineral potential. Gold potential is mostly associated with the Inglis Fault, the Yampi Fold Belt and the central portion of the King Leopold Orogen. The centre, west and east of the King Leopold Orogen and parts of the Yampi Fold Belt show small, but high, regions of mineral potential for stratiform-hosted base metal deposits. The northwest and east of the King Leopold Orogen show small regions of tin-tungsten mineral potential. Intrusion-related base metal mineral potential is restricted to the Wotjulum Porphyry in the Yampi Fold Belt and the northern central part of the King Leopold Orogen

Prairie People’s Packers Pending: The New Generation Cooperative Model of Cattle Slaughter

Paper presented at the Canadian Association of Geographers meeting, Thunder Bay, June 2006.N

Oxo-stabilised phosphonium ylides as hydrogen bond acceptors

Oxo-stabilised phosphonium ylides are found to form crystalline hydrogen-bonded adducts with aromatic carboxylic acids as confirmed by X-ray diffraction. There is also strong hydrogen bonding in solution as indicated by 13C NMR spectroscopy and this confirmed adduct formation with acetic acid, benzamide, thiobenzamide, benzyl alcohol, benzenesulfinic acid and diphenylphosphinic acid. The X-ray structure of the benzamide adduct was also determined showing a hydrogen-bonded dimeric structure. A bis(stabilised ylide) was also prepared and is found to form a complex hydrogen-bonded adduct with benzoic acid, ethanol and water.Publisher PDFPeer reviewe