528 research outputs found

    Do Macroalgal Environments Leave a Geological Signature? Modern Test Case from Kaikoura, New Zealand

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    Brown, red and green macroalgae in modern temperate marine environments are ecosystem‐forming primary producers on rocky substrates, yet they have a poor preservation potential and few fossil examples are known from the rock record. Macroalgal forests, as carbonate producers, are largely unrecognised within the coolwater carbonate realm even though they host a wide variety of calcareous organisms with good preservational potential. Some species of molluscs, sea urchins and crustaceans only live within the understorey of macroalgal forests. These, and other, calcareous flora and fauna are the key to identification of macroalgae environments in the rock record. Modern macroalgae forests at Kaikoura, New Zealand, exhibit a clear zonation of calcareous components controlled by substrate topography, wave exposure, water depth and light penetration. The prominent live calcareous components include encrusting and foliose coralline red algae, molluscs, bryozoans, echinoderms, calcareous worms, ascidians and crustaceans, as well as sponges and other soft bodied invertebrates. The sediments accumulated beneath and adjacent to the algae at Kaikoura are bioclastic, terrigenous sands and gravels; with bioclasts of coralline algal fragments and rhodoliths, barnacles, molluscs, spirorbids and bryozoans. Although the shallow, wave exposed settings that promote growth of macroalgal forests are limited in areal extent, their contribution via skeletal carbonate may be considerable. In the rock record, terrigenous sands and gravels rich in coralline, barnacle, mollusc, and bryozoan fragments, that occur in association with hard‐substrate unconformities in a cool‐water realm, must be considered as representatives of past macroalgal environments

    A methodology for systematic mapping in environmental sciences

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    Systematic mapping was developed in social sciences in response to a lack of empirical data when answering questions using systematic review methods, and a need for a method to describe the literature across a broad subject of interest. Systematic mapping does not attempt to answer a specific question as do systematic reviews, but instead collates, describes and catalogues available evidence (e.g. primary, secondary, theoretical, economic) relating to a topic or question of interest. The included studies can be used to identify evidence for policy-relevant questions, knowledge gaps (to help direct future primary research) and knowledge clusters (sub-sets of evidence that may be suitable for secondary research, for example systematic review). Evidence synthesis in environmental sciences faces similar challenges to those found in social sciences. Here we describe the translation of systematic mapping methodology from social sciences for use in environmental sciences. We provide the first process-based methodology for systematic maps, describing the stages involved: establishing the review team and engaging stakeholders; setting the scope and question; setting inclusion criteria for studies; scoping stage; protocol development and publication; searching for evidence; screening evidence; coding; production of a systematic map database; critical appraisal (optional); describing and visualising the findings; report production and supporting information. We discuss the similarities and differences in methodology between systematic review and systematic mapping and provide guidance for those choosing which type of synthesis is most suitable for their requirements. Furthermore, we discuss the merits and uses of systematic mapping and make recommendations for improving this evolving methodology in environmental sciences

    Evidence for the effects of neonicotinoids used in arable crop production on non-target organisms and concentrations of residues in relevant matrices: a systematic map protocol

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    Background Neonicotinoid insecticides (NNIs) have been routinely used in arable crop protection since their development in the early 1990s. These insecticides have been subject to the same registration procedures as other groups of pesticides, thus meet the same environmental hazard standards as all crop protection products. However, during the last 10 years the debate regarding their possible detrimental impact on non-target organisms, particularly pollinators, has become increasingly contentious and widely debated. Against this background, legislators and politicians in some countries, have been faced with a need to make decisions on the future registration of some or all of this class of insecticides, based on published evidence that in some areas is incomplete or limited in extent. This has created much concern in agricultural communities that consider that the withdrawal of these insecticides is likely to have significant negative economic, socio-economic and environmental consequences. Methods The proposed systematic map aims to address the following primary question: What is the available evidence for the effects of neonicotinoids used in arable crop production on non-target organisms and concentrations of residues in relevant matrices? The primary question will be divided into two sub-questions to gather research literature for (1) the effect of NNIs on non-target organisms (2) the occurrence of concentrations of NNIs in matrices of relevance to non-target organisms (i.e. exposure routes). The systematic map will focus on NNIs used in arable crop production: imidacloprid, clothianidin, thiamethoxam, acetamiprid, thiacloprid and dinotefuran. Separate inclusion criteria have been developed for each sub-question. Traditional academic and grey literature will be searched for in English language and a searchable databases containing extracted meta-data from relevant included studies will be developed

    The conservation of human functional variants and their effects across mammals

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    Despite the clear potential of livestock models of human functional variants to provide important insights into the biological mechanisms driving human diseases and traits, their use to date has been limited. Generating such models via genome editing is costly and time consuming, and it is unclear which variants will have conserved effects across species. In this study we address these issues by studying naturally occurring livestock models of human functional variants. We show that orthologues of over 1.6 million human variants are already segregating in domesticated mammalian species, including several hundred previously directly linked to human traits and diseases. Models of variants linked to particular phenotypes, including metabolomic disorders and height, are preferentially shared across species, meaning studying the genetic basis of these phenotypes is particularly tractable in livestock. Using machine learning we demonstrate it is possible to identify human variants that are more likely to have an existing livestock orthologue, and, importantly, we show that the effects of functional variants are often conserved in livestock, acting on orthologous genes with the same direction of effect. Consequently, this work demonstrates the substantial potential of naturally occurring livestock carriers of orthologues of human functional variants to disentangle their functional impacts

    Comparing Formulations of Generalized Quantum Mechanics for Reparametrization-Invariant Systems

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    A class of decoherence schemes is described for implementing the principles of generalized quantum theory in reparametrization-invariant `hyperbolic' models such as minisuperspace quantum cosmology. The connection with sum-over-histories constructions is exhibited and the physical equivalence or inequivalence of different such schemes is analyzed. The discussion focuses on comparing constructions based on the Klein-Gordon product with those based on the induced (a.k.a. Rieffel, Refined Algebraic, Group Averaging, or Spectral Analysis) inner product. It is shown that the Klein-Gordon and induced products can be simply related for the models of interest. This fact is then used to establish isomorphisms between certain decoherence schemes based on these products.Comment: 21 pages ReVTe

    Systematic screening to integrate reproductive health services in India

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    This study, conducted in large public clinics and small health posts in the city of Vadodara, India, tested the effectiveness of a systematic screening technique in integrating reproductive health services at the provider level. The objective was to determine if women screened during clinic visits received more services, appointments, and referrals per visit than women who were not screened. Results show that in experimental group clinics the number of services per visit increased while control clinics experienced a slight decrease; the effect of systematic screening was smaller in health posts than in clinics. In experimental posts, services per visit increased by nine percent compared to a decrease of 16 percent among controls. The municipality of Vadodara will begin systematic screening in all clinics. Gujarat state, where Vadodara is located, also plans to adopt the intervention

    Lacustrine stromatolites: Useful structures for environmental interpretation – an example from the Miocene Ebro Basin

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    The significance of stromatolites as depositional environmental indicators and the underlying causes of lamination in the lacustrine realm are poorly understood. Stromatolites in a ca 600 m thick Miocene succession in the Ebro Basin are good candidates to shed light on these issues because they are intimately related to other lacustrine carbonate and sulphate facies, grew under variable environmental conditions and show distinct lamination patterns. These stromatolites are associated with wave-related, clastic-carbonate laminated limestones. Both facies consist of calcite and variable amounts of dolomite. Thin planar stromatolites (up to 10 cm thick and less than 6 m long) occurred in very shallow water. These stromatolites represented first biological colonization after: (i) subaerial exposure in the palustrine environment (i.e. at the beginning of deepening cycles); or (ii) erosion due to surge action, then coating very irregular surfaces on laminated limestones (i.e. through shallowing or deepening cycles). Sometimes they are associated with evaporative pumping. Stratiform stromatolites (10 to 30 cm high and tens of metres long) and domed stromatolites (10 to 30 cm high and long) developed in deeper settings, between the surge periods that produced hummocky cross-stratification and horizontal lamination offshore. Changes in stromatolite lamina shape, and thus in the growth forms through time, can be attributed to changes in water depth, whereas variations in lamina continuity are linked to water energy and sediment supply. Growth of the stromatolites resulted from in situ calcite precipitation and capture of minor amounts of fine-grained carbonate particles. Based on texture, four types of simple laminae are distinguished. The simple micrite and microsparite laminae can be grouped into light and dark composite laminae, which represent, respectively, high and low Precipitation/Evaporation ratio periods. Different lamination patterns provide new ideas for the interpretation of microbial laminations as a function of variations in climate-dependent parameters (primarily the Precipitation/Evaporation ratio) over variable timescales

    Dynamical Renormalization Group Approach to Quantum Kinetics in Scalar and Gauge Theories

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    We derive quantum kinetic equations from a quantum field theory implementing a diagrammatic perturbative expansion improved by a resummation via the dynamical renormalization group. The method begins by obtaining the equation of motion of the distribution function in perturbation theory. The solution of this equation of motion reveals secular terms that grow in time, the dynamical renormalization group resums these secular terms in real time and leads directly to the quantum kinetic equation. We used this method to study the relaxation in a cool gas of pions and sigma mesons in the O(4) chiral linear sigma model. We obtain in relaxation time approximation the pion and sigma meson relaxation rates. We also find that in large momentum limit emission and absorption of massless pions result in threshold infrared divergence in sigma meson relaxation rate and lead to a crossover behavior in relaxation. We then study the relaxation of charged quasiparticles in scalar electrodynamics (SQED). While longitudinal, Debye screened photons lead to purely exponential relaxation, transverse photons, only dynamically screened by Landau damping lead to anomalous relaxation, thus leading to a crossover between two different relaxational regimes. We emphasize that infrared divergent damping rates are indicative of non-exponential relaxation and the dynamical renormalization group reveals the correct relaxation directly in real time. Finally we also show that this method provides a natural framework to interpret and resolve the issue of pinch singularities out of equilibrium and establish a direct correspondence between pinch singularities and secular terms. We argue that this method is particularly well suited to study quantum kinetics and transport in gauge theories.Comment: RevTeX, 40 pages, 4 eps figures, published versio

    The quasiclassical realms of this quantum universe

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    The most striking observable feature of our indeterministic quantum universe is the wide range of time, place, and scale on which the deterministic laws of classical physics hold to an excellent approximation. This essay describes how this domain of classical predictability of every day experience emerges from a quantum theory of the universe's state and dynamics.Comment: 24 pages, revtex4, minor change

    A new measurement of the Collins and Sivers asymmetries on a transversely polarised deuteron target

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    New high precision measurements of the Collins and Sivers asymmetries of charged hadrons produced in deep-inelastic scattering of muons on a transversely polarised 6LiD target are presented. The data were taken in 2003 and 2004 with the COMPASS spectrometer using the muon beam of the CERN SPS at 160 GeV/c. Both the Collins and Sivers asymmetries turn out to be compatible with zero, within the present statistical errors, which are more than a factor of 2 smaller than those of the published COMPASS results from the 2002 data. The final results from the 2002, 2003 and 2004 runs are compared with naive expectations and with existing model calculations.Comment: 40 pages, 28 figure
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