Nonparametric rank regression for analyzing water quality concentration data with multiple detection limits

Environmental data usually include measurements, such as water quality data, which fall below detection limits, because of limitations of the instruments or of certain analytical methods used. The fact that some responses are not detected needs to be properly taken into account in statistical analysis of such data. However, it is well-known that it is challenging to analyze a data set with detection limits, and we often have to rely on the traditional parametric methods or simple imputation methods. Distributional assumptions can lead to biased inference and justification of distributions is often not possible when the data are correlated and there is a large proportion of data below detection limits. The extent of bias is usually unknown. To draw valid conclusions and hence provide useful advice for environmental management authorities, it is essential to develop and apply an appropriate statistical methodology. This paper proposes rank-based procedures for analyzing non-normally distributed data collected at different sites over a period of time in the presence of multiple detection limits. To take account of temporal correlations within each site, we propose an optimal linear combination of estimating functions and apply the induced smoothing method to reduce the computational burden. Finally, we apply the proposed method to the water quality data collected at Susquehanna River Basin in United States of America, which dearly demonstrates the advantages of the rank regression models.

Statistical power calculation and sample size determination for environmental studies with data below detection limits

Power calculation and sample size determination are critical in designing environmental monitoring programs. The traditional approach based on comparing the mean values may become statistically inappropriate and even invalid when substantial proportions of the response values are below the detection limits or censored because strong distributional assumptions have to be made on the censored observations when implementing the traditional procedures. In this paper, we propose a quantile methodology that is robust to outliers and can also handle data with a substantial proportion of below-detection-limit observations without the need of imputing the censored values. As a demonstration, we applied the methods to a nutrient monitoring project, which is a part of the Perth Long-Term Ocean Outlet Monitoring Program. In this example, the sample size required by our quantile methodology is, in fact, smaller than that by the traditional t-test, illustrating the merit of our method.

Stretching water - Queensland’s water use efficiency cotton and grains adoption program

The Cotton and Grain Adoption Program of the Queensland Rural Water Use Efficiency Initiative is targeting five major irrigation regions in the state with the objective to develop better irrigation water use efficiency (WUE) through the adoption of best management practices in irrigation. The major beneficiaries of the program will be industries, irrigators and local communities. The benefits will flow via two avenues: increased production and profit resulting from improved WUE and improved environmental health as a consequence of greatly reduced runoff of irrigation tailwater into rivers and streams. This in turn will reduce the risk of nutrient and pesticide contamination of waterways. As a side effect, the work is likely to contribute to an improved public image of the cotton and grain industries. In each of the five regions, WUE officers have established grower groups to assist in providing local input into the specific objectives of extension and demonstration activities. The groups also assist in developing growers' perceptions of ownership of the work. Activities are based around four on-farm demonstration sites in each region where irrigation management techniques and hardware are showcased. A key theme of the program is monitoring water use. This is applied both to on-farm storage and distribution as well as to application methods and in-field management. This paper describes the project, its activities and successes.

At the Limits of Presentation : Coming-into-Presence and its Aesthetic Relevance in Jean-Luc Nancy's Philosophy

This study investigates the significance of art in Jean-Luc Nancy s philosophy. I argue that the notion of art contributes to some of Nancy s central ontological ideas. Therefore, I consider art s importance in its own right whether art does have ontological significance, and if so, how one should describe this with respect to the theme of presentation. According to my central argument, with his thinking on art Nancy attempts to give one viewpoint to what is called the metaphysics of presence and to its deconstruction. On which grounds, as I propose, may one say that art is not reducible to philosophy? The thesis is divided into two main parts. The first part, Presentation as a Philosophical Theme, is a historical genesis of the central concepts associated with the birth of presentation in Nancy s philosophy. I examine this from the viewpoint of the differentiation between the ontological notions of presentation and representation by concentrating on the influence of Martin Heidegger and Jacques Derrida, as well as of Hegel and Kant. I give an overview of the way in which being or sense for Nancy is to be described as a coming-into-presence or presentation . Therefore, being takes place in its singular plurality. I argue that Nancy redevelops Heidegger s account of being in two principal ways: first, in rethinking the ontico-ontological difference, and secondly, by striving to radicalize the Heideggerian concept of Mitsein, being-with . I equally wish to show the importance of Derrida s notion of différance and its inherence in Nancy s questioning of being that rests on the unfoundedness of existence. The second part, From Ontology to Art, draws on the importance of art and the aesthetic. If, in Nancy, the question of art touches upon its own limit as the limit of nothingness, how is art able to open its own strangeness and our exposure to this strangeness? My aim is to investigate how Nancy s thinking on art finds its place within the conceptual realm of its inherent difference and interval. My central concern is the thought of originary ungroundedness and the plurality of art and of the arts. As for the question of the difference between art and philosophy, I wish to show that what differentiates art from thought is the fact that art exposes what is obvious but not apparent, if apparent is understood in the sense of givenness. As for art s ability to deconstruct Nancy s ontological notions, I suggest that in question in art is its original heterogeneity and diversity. Art is a matter of differing art occurs singularly, as a local difference. With this in mind, I point out that in reflecting on art in terms of spacing and interval, as a thinker of difference Nancy comes closer to Derrida and his idea of différance than to the structure of Heidegger s ontological difference.

Counter-figures : An Essay on Antimetaphoric Resistance: Paul Celan's Poetry and Poetics at the Limits of Figurality

Titled "An Essay on Antimetaphoric Resistance", the dissertation investigates what is here being called "Counter-figures": a term which has in this context a certain variety of applications. Any other-than-image or other-than-figure, anything that cannot be exhausted by figuration (and that is, more or less, anything at all, except perhaps the reproducible images and figures themselves) can be considered "counter-figurative" with regard to the formation of images and figures, ideas and schemas, "any graven image, or any likeness of any thing". Singularity and radical alterity, as well as temporality and its peculiar mode of uniqueness are key issues here, and an ethical dimension is implied by, or intertwined with, the aesthetic. In terms borrowed from Paul Celan's "Meridian" speech, poetry may "allow the most idiosyncratic quality of the Other, its time, to participate in the dialogue". This connection between singularity, alterity and temporality is one of the reasons why Celan so strongly objects to the application of the traditional concept of metaphor to poetry. As Celan says, "carrying over [übertragen]" by metaphor may imply an unwillingness to "bear with [mittragen]" and to "endure [ertragen]" the poem. The thesis is divided into two main parts. The first consists of five distinct prolegomena which all address the mentioned variety of applications of the term "counter-figures", and especially the rejection or critique of either metaphor (by Aristotle, for instance) or the concept of metaphor (defined by Aristotle, and sometimes deemed "anti-poetic" by both theorists and poets). Even if we restrict ourselves to the traditional rhetorico-poetical terms, we may see how, for instance, metonymy can be a counter-figure for metaphor, allegory for symbol, and irony for any single trope or for any piece of discourse at all. The limits of figurality may indeed be located at these points of intersection between different types of tropes or figures, and even between figures or tropes and the "non-figurative trope" or "pseudo-figure" called catachresis. The second part, following on from the open-ended prolegomena, concentrates on Paul Celan's poetry and poetics. According to Celan, true poetry is "essentially anti-metaphoric". I argue that inasmuch as we are willing to pay attention to the "will" of the poetic images themselves (the tropes and metaphors in a poem) to be "carried ad absurdum", as Celan invites us to do, we may find alternative ways of reading poetry and approaching its "secret of the encounter", precisely when the traditional rhetorical instruments, and especially the notion of metaphor, become inapplicable or suspicious — and even where they still seem to impose themselves.

Near infrared spectroscopy as a rapid tool to measure volatile aroma compounds in Riesling wine: Possibilities and limits

Volatile chemical compounds responsible for the aroma of wine are derived from a number of different biochemical and chemical pathways. These chemical compounds are formed during grape berry metabolism, crushing of the berries, fermentation processes (i.e. yeast and malolactic bacteria) and also from the ageing and storage of wine. Not surprisingly, there are a large number of chemical classes of compounds found in wine which are present at varying concentrations (ng L-1 to mg L-1), exhibit differing potencies, and have a broad range of volatilities and boiling points. The aim of this work was to investigate the potential use of near infrared (NIR) spectroscopy combined with chemometrics as a rapid and low-cost technique to measure volatile compounds in Riesling wines. Samples of commercial Riesling wine were analyzed using an NIR instrument and volatile compounds by gas chromatography (GC) coupled with selected ion monitoring mass spectrometry. Correlation between the NIR and GC data were developed using partial least-squares (PLS) regression with full cross validation (leave one out). Coefficients of determination in cross validation (R 2) and the standard error in cross validation (SECV) were 0.74 (SECV: 313.6 μg L−1) for esters, 0.90 (SECV: 20.9 μg L−1) for monoterpenes and 0.80 (SECV: 1658 ?g L-1) for short-chain fatty acids. This study has shown that volatile chemical compounds present in wine can be measured by NIR spectroscopy. Further development with larger data sets will be required to test the predictive ability of the NIR calibration models developed.

Unsteady, three-dimensional, boundary-layer flow due to a stretching surface

Abstract is not available.

Theoretical Maximum Limits on Power-Handling Capacity of HVDC Cables

In the case of an ac cable, power transmission is limited by the length of the cable due to the capacitive reactive current component. It is well known that high-voltage direct current (HVDC) cables do not have such limitations. However, insulation-related thermal problems pose a limitation on the power capability of HVDC cables. The author presents a viable theoretical development, a logical extension to Whitehead's theory on thermal limitations of the insulation. The computation of the maximum power-carrying capability of HVDC cables subject to limits on the maximum operable temperature of the insulation is presented. The limitation on the power-carrying capability is closely associated with the electrothermal insulation failure. The effect of environmental interaction by way of external thermal resistance, an important aspect, is also considered in the formulations. The Lagrange multiplier method has been used to handle the ensuing optimization problem. The theory is based on an accepted theory of thermal breakdown in insulation and is an important and a coherent extension of great significance.

Uncertainty in length measurements of live coral trout: implications for compliance and enforcement of minimum legal size limits.

Report on evidence of shrinkage of live coral trout during professional fishing operations on the Great Barrier Reef in 2000. Excel data includes the following fields: Column A. Fish (fish number from 1 -24) Column B. Bin (1-8, container the fish was held in during the experiment) Column C. Measure (1-7, number of the measurement of each fish) Column D. Observer (1 or 2, making the measurement) Column E. Time 2 Column F. Time (time of the day the measurement was made) Column G. FL (Fork Length) Column H. TL (Total Length) Column I. Difference (difference in length between measures) Column J. Order Column K. Temperature (surface water temp under the boat)

Stretching single DNA-molecules with temperature-stabilized optical tweezers

This thesis consists of two parts; in the first part we performed a single-molecule force extension measurement with 10kb long DNA-molecules from phage-λ to validate the calibration and single-molecule capability of our optical tweezers instrument. Fitting the worm-like chain interpolation formula to the data revealed that ca. 71% of the DNA tethers featured a contour length within ±15% of the expected value (3.38 µm). Only 25% of the found DNA had a persistence length between 30 and 60 nm. The correct value should be within 40 to 60 nm. In the second part we designed and built a precise temperature controller to remove thermal fluctuations that cause drifting of the optical trap. The controller uses feed-forward and PID (proportional-integral-derivative) feedback to achieve 1.58 mK precision and 0.3 K absolute accuracy. During a 5 min test run it reduced drifting of the trap from 1.4 nm/min in open-loop to 0.6 nm/min in closed-loop.

Improved chemical control of Conyza bonariensis in wheat limits problems in the following fallow

Conyza bonariensis is a major weed infesting zero-tilled cropping systems in subtropical Australia, particularly in wheat and winter fallows. Uncontrolled C.bonariensis survives to become a problem weed in the following crops or fallows. As no herbicide has been registered for C.bonariensis in wheat, the effectiveness of 11 herbicides, currently registered for other broad-leaved weeds in wheat, was evaluated in two pot and two field experiments. As previous research showed that the age of C.bonariensis, and to a lesser extent, the soil moisture at spraying affected herbicide efficacy, these factors also were investigated. The efficacy of the majority of herbicide treatments was reduced when large rosettes (5-15cm diameter) were treated, compared with small rosettes (<5cm diameter). However, for the majority of herbicide treatments, the soil moisture did not affect the herbicide efficacy in the pot experiments. In the field, a delay in herbicide treatment of 2 weeks reduced the herbicide efficacy consistently across herbicide treatments, which was related to weed age but not to soil moisture differences. Across all the experiments, four herbicides controlled C.bonariensis in wheat consistently (83-100%): 2,4-D; aminopyralid + fluroxypyr; picloram + MCPA + metsulfuron; and picloram + high rates of 2,4-D. Thus, this problem weed can be effectively and consistently controlled in wheat, particularly when small rosettes are treated, and therefore C.bonariensis will have a less adverse impact on the following fallow or crop.

On Random Planar Curves and Their Scaling Limits

Planar curves arise naturally as interfaces between two regions of the plane. An important part of statistical physics is the study of lattice models. This thesis is about the interfaces of 2D lattice models. The scaling limit is an infinite system limit which is taken by letting the lattice mesh decrease to zero. At criticality, the scaling limit of an interface is one of the SLE curves (Schramm-Loewner evolution), introduced by Oded Schramm. This family of random curves is parametrized by a real variable, which determines the universality class of the model. The first and the second paper of this thesis study properties of SLEs. They contain two different methods to study the whole SLE curve, which is, in fact, the most interesting object from the statistical physics point of view. These methods are applied to study two symmetries of SLE: reversibility and duality. The first paper uses an algebraic method and a representation of the Virasoro algebra to find common martingales to different processes, and that way, to confirm the symmetries for polynomial expected values of natural SLE data. In the second paper, a recursion is obtained for the same kind of expected values. The recursion is based on stationarity of the law of the whole SLE curve under a SLE induced flow. The third paper deals with one of the most central questions of the field and provides a framework of estimates for describing 2D scaling limits by SLE curves. In particular, it is shown that a weak estimate on the probability of an annulus crossing implies that a random curve arising from a statistical physics model will have scaling limits and those will be well-described by Loewner evolutions with random driving forces.

A computer study of the miscibility limits of Sb1bTe1bBi

The quaternary system Sb1bTe1bBi1bSe with small amounts of suitable dopants is of interest for the manufacture of thermoelectric modules which exhibit the Peltier and Seebeck effects. This property could be useful in the production of energy from the thermoelectric effect. Other substances are bismuth telluride (Bi2Te3) and Sb1bTe1bBi and compounds such as ZnIn2Se4. In the present paper the application of computer programs such as MIGAP of Kaufman is used to indicate the stability of the ternary limits of Sb1bTe1bBi within the temperature ranges of interest, namely 273 K to 300 K.

Intrinsic limits of subthreshold slope in biased bilayer graphene transistor

In this work, we investigate the intrinsic limits of subthreshold slope in a dual gated bilayer graphene transistor using a coupled self-consistent Poisson-bandstructure solver. We benchmark the solver by matching the bias dependent band gap results obtained from the solver against published experimental data. We show that the intrinsic bias dependence of the electronic structure and the self-consistent electrostatics limit the subthreshold slope obtained in such a transistor well above the Boltzmann limit of 60 mV/decade at room temperature, but much below the results experimentally shown till date, indicating room for technological improvement of bilayer graphene.