Resource allocation, hyperphagia and compensatory growth

Organisms often shown enhanced growth during recovery from starvation, and can even overtake continuously fed conspecifics (overcompensation). In an earlier paper (Ecology 84, 2777-2787), we studied the relative role played by hyperphagia and resource allocation in producing overcompensation in juvenile (non-reproductive) animals. We found that, although hyperphagia always produces growth compensation, overcompensation additionally requires protein allocation control which routes assimilate preferentially to structure during recovery. In this paper we extend our model to cover reproductively active individuals and demonstrate that growth rate overcompensation requires a similar combination of hyperphagia and allocation control which routes the part of enhanced assimilation not used for reproduction preferentially towards structural growth. We compare the properties of our dynamic energy budget model with an earlier proposal, due to Kooijman, which we extend to include hyperphagia. This formulation assumes that the rate of allocation to reserves is controlled by instantaneous feeding rate, and one would thus expect that an extension to include hyperphagia would not predict growth overcompensation. However, we show that a self-consistent representation of the hyperphagic response in Kooijman's model overrides its fundamental dynamics, leading to preferential allocation to structural growth during recovery and hence to growth overcompensation

Presunrise Heating of the Ambient Electrons in the Ionosphere Due to Conjugate Point Photoelectrons

Presunrise heating of ambient electrons in ionosphere due to conjugate point photoelectron

Greenstone belt tectonics: Thermal constraints

Archaean rocks provide a record of the early stages of planetary evolution. The interpretation is frustrated by the probable unrepresentative nature of the preserved crust and by the well known ambiguities of tectonic geological synthesis. Broad constraints can be placed on the tectonic processes in the early Earth from global scale modeling of thermal and chemical evolution of the Earth and its hydrosphere and atmosphere. The Archean record is the main test of such models. Available general model constraints are outlined based on the global tectonic setting within which Archaean crust evolved and on the direct evidence the Archaean record provides, particularly the thermal state of the early Earth

Media(ted) fabrications: How the science-media symbiosis helped ‘sell’ cord banking

This paper considers the problematic role of the science–media symbiosis in the dissemination of misleading and emotionally manipulative information regarding services offered by CordBank, New Zealand's only umbilical cord blood banking facility. As this case study illustrates, the growing reliance of health and science reporters on the knowledge capital of medical specialists, biogenetic researchers, and scientists potentially enhances the ability of ‘expert’ sources to set the agenda for media representations of emerging medical and scientific developments, and may undermine the editorial independence of journalists and editors, many of whom in this case failed to critically evaluate deeply problematic claims regarding the current and future benefits of cord banking. Heavy reliance on established media frames of anecdotal personalization and technoboosterism also reinforced a proscience journalistic culture in which claims by key sources were uncritically reiterated and amplified, with journalistic assessments of the value of cord banking emphasizing potential benefits for individual consumers. It is argued that use of these media frames potentially detracts from due consideration of the broader social, ethical, legal, and health implications of emerging biomedical developments, along with the professional, personal, and increasingly also financial interests at stake in their public promotion, given the growing commercialization of biogenetic technologies

Some reactions of phosphorus compounds as studied by 31p nmr techniques

The solution chemistry of some simple phosphorus halides has been investigated in sulphuric acid, oleums, and halo-substituted sulphuric acids by (^31) p n.m.r. spectroscopy. Solution of phosphorus (III) compounds was accompanied by oxidation to the phosphorus (V) state. The phosphorus (V) species so formed as well as those derived directly from phosphorus (V) halides and oxyhalides were stable over measurable periods of time. Solvolysis of phosphorus (V) – halogen bonds occurred in all the solvents, with some complications arising in the halo-substituted acids where halogen exchange was observed. Oxidation of some phosphorus (III) halides by halogens produced phosphorus (V) - halo species which were stabilized by solution in these highly acidic solvents. The (^31) p n.m.r. solution spectrum of various phosphorus (V) - iodine species have been recorded for the first time with the help of a pulsed Fourier Transform instrument capable of studying reacting systems. The solution chemistry of a series of phenyl organophosphoryl compounds in these acid solvents has also been investigated by (^31) P n.m.r. Protonation of the phosphoryl group takes place in all of the solvents, as well as sulphonation of the phenyl ring in 25% and 65% oleum, and to a lesser extent in ClHSO (_3). Mixed halo and organohalo phosphorus (V) compounds such as [PCl (_N) Br (_4-n)] (^+) A (^-), R (_N) PX (_5-n), [R (_n) PX (_4-n)] (^+) A (^-), where X = Cl or Br and A (^-) is an anion, dissolve in 25% oleum with the formation of stable phosphonium cations. An investigation of the solution chemistry of phenoxyhalophosphoranes indicates that the stable species in the system are the non halo containing (PhO) (_4) p (^+) cation and (PhO) (_5) P, neither of which show acceptor properties towards pyridine or chloride ions. A limited investigation of the Lewis acid properties of PI (_3) towards pyridines and the Lewis base properties of PI (_3) towards BBr (_3) and BIr (_3) suggests that coordination complexes are formed in both systems. Oxidation of PI (_3) has been attempted by means of halogens and other halogen-containing oxidizing agents. No direct evidence for the formation of phosphorus (V)-iodine species was obtained, although reactions with SbCl (_5) and PCl (_5) produced unstable compounds which decomposed at low temperature liberating iodine

Aspects of peptide transport in saccharomyces cerevisiae and streptococcus spp.

Two novel fluorescence methods for the assay of peptide transport in microorganisms are described. These methods are compared with conventional radiotracer assays, and certain advantages of the fluorescence techniques are highlighted. Peptide uptake in the yeast Saccharomyces cerevisiae is investigated. It is shown that peptide and amino acid uptake are distinct, intact peptide accumulation is demonstrated, and the presence of a single main peptide permease, which handles a range of di- and tripeptides, is demonstrated. A mutant deficient in this permease is isolated on the basis of resistance to the dipeptide-mimetic antibiotic bacilysin. Peptide uptake in Streptococcus faecalis is also shown to be distinct from amino acid transport, and intact peptide accumulation is again demonstrated. A strain of Strep, faecalis (faecium) is shown to possess two peptide permeases, a high-rate system for di- and tripeptides, and a low-rate oligopeptide system. Other strains of Strep, faecalis are shown to differ in their peptide transport specificity. Mutant strains deficient in peptide permeases or intracellular peptiaases are isolated on the basis of resistance to peptide mimetic antibiotics. The coupling of metabolic energy to peptide transport is investigated in Sacc. cerevisiae and Strep, faecalis. In both cases a proton-motive-force is implicated. Some preliminary investigations of the energy consumption of peptide transport in Strep, faecalis, implying the same stoichiometry for tri-, tetra- and pentaalanine uptake, are reported

Seasonal reproduction in a fluctuating energy environment: Insolation-driven synchronized broadcast spawning in corals

*Background/Question/Methods:* Colonies of spawning corals reproduce in mass-spawning events, in which polyps within each colony release sperm and eggs for fertilization in the water column, with fertilization occurring only between gametes from different colonies. Participating colonies synchronize their gamete release to a window of a few hours once a year (for the species Acropora digitifera we study experimentally). This remarkable synchrony is essential for successful coral reproduction and thus, maintenance of the coral reef ecosystem that is currently under threat from local and global environmental effects such as pollution, global warming and ocean acidification. The mechanisms determining this tight synchrony in reproduction are not well understood, although several influences have been hypothesized and studied including lunar phase, solar insolation, and influences of temperature and tides. Moreover, most corals are in a symbiotic relationship with photosynthetic algae (Symbiodinium spp.) that live within the host tissue. Experiments supported by detailed bioenergetic modeling of the coral-algae symbiosis have shown that corals receive >90% of their energy needs from these symbionts. We develop a bioenergetic integrate-and-fire model in order to investigate whether annual insolation rhythms can entrain the gametogenetic cycles that produce mature gametes to the appropriate spawning season, since photosynthate is their primary source of energy. We solve the integrate-and-fire bioenergetic model numerically using the Fokker-Planck equation and use analytical tools such as rotation number to study entrainment.

*Results/Conclusions:* In the presence of short-term fluctuations in the energy input, our model shows that a feedback regulatory mechanism is required to achieve coherence of spawning times to within one lunar cycle, in order for subsequent cues such as lunar and diurnal light cycles to unambiguously determine the “correct” night of spawning. Entrainment to the annual insolation cycle is by itself not sufficient to produce the observed coherence in spawning. The feedback mechanism can also provide robustness against population heterogeneity due to genetic and environmental effects. We also discuss how such bioenergetic, stochastic, integrate-and-fire models are also more generally applicable: for example to aquatic insect emergence, synchrony in cell division and masting in trees

Photonic qubits, qutrits and ququads accurately prepared and delivered on demand

Reliable encoding of information in quantum systems is crucial to all approaches to quantum information processing or communication. This applies in particular to photons used in linear optics quantum computing (LOQC), which is scalable provided a deterministic single-photon emission and preparation is available. Here, we show that narrowband photons deterministically emitted from an atom-cavity system fulfill these requirements. Within their 500 ns coherence time, we demonstrate a subdivision into d time bins of various amplitudes and phases, which we use for encoding arbitrary qu-d-its. The latter is done deterministically with a fidelity >95% for qubits, verified using a newly developed time-resolved quantum-homodyne method.Comment: 5 pages, 4 figure

Public Health England's recovery tools: potential teaching resources?

The file attached to this record is the author's final peer reviewed version.Training to combat chemical and radiation accidents, incidents or attacks is critical for health professionals due to recent events involving these hazards or their use as unconventional weapons, such as the use of the nerve agent novichok in Salisbury, UK. Health professionals need to have appropriate knowledge and skills to effectively respond to future events involving any of these substances, which requires a rapid and coordinated response from different professionals to protect the environment and minimise the number of people exposed and reduce morbidity and mortality. However, despite chemical and radiation incidents becoming increasingly prevalent, literature reviews have shown that there is a lack of teaching of appropriate competences to face future crises in Europe, particularly amongst clinicians and other health professionals that would be part of the initial response. Thus, De Montfort University (DMU, UK) in collaboration with different academics from the University of Alcalá (Spain) and researchers from Public Health England (PHE) with comprehensive experience in environmental decontamination and restoration, have created a short training course for providing undergraduate/postgraduate students with basic skills to respond to chemical incidents, basic skills that are based on the major competences recently identified by the European Commission [1]. This novel training has been tested with students from different backgrounds in various European universities, recording high degrees of acquisition of the various basic competences that we developed to initially respond to chemical events [2]. To develop the practical part of this chemical training, we have incorporated the novel guidance and methodology developed by PHE to successfully tailor a protection and recovery response to any incident involving chemical substances, which is available in the “UK Recovery Handbook for Chemical Incidents” [3] and its web-based tools: “Chemical Recovery Navigation Tool” (CRNT, [4]) and “Chemical Recovery Record Form” (CRRF, [5]). These innovative resources aid the user to select effective protection, decontamination and restoration techniques or strategies from a pool of up-to-date options applicable to different environments according to the physicochemical properties of the chemical(s) involved and the area affected. The CRNT is accompanied by the CRRF, which facilitates collection and analysis of the necessary data to inform decisions, and an e-learning resource named “Chemical Recovery: Background” (CRB, [6]), which could facilitate the learning of environmental decontamination and restoration. We are currently developing a short training course to cover minor radiation incidents; this radiation training will follow the same methods used to develop the chemical training, but with the specific PHE recovery tools to tackle such events, specifically the “UK Recovery Handbooks for Radiation Incidents” [7] and its associated web-based tools “Radiation Recovery Navigation Tool” (Rad RNT, [8]), one for each environment: food production systems, inhabited areas and drinking water supplies. This communication will explore the use of the PHE’s Recovery Navigation Tools as potential resources to facilitate the acquisition of basic knowledge to tailor protection and recovery interventions for minor chemical and radiation incidents to protect the public