cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Dissolved Organic Matter in the Upwelling System off Peru: Imprints of Bacterial Activity and Water Mass Characteristics
Creators: name: Maßmig, Marie
name: Engel, Anja
Publisher: name: FID GEO
Year: 2021

description: Microbial degradation of dissolved organic matter (DOM) contributes to the formation and preservation of oxygen minimum zones (OMZs) in the ocean, but information on the spatial distribution and molecular composition of DOM in OMZ regions is scarce. We quantified molecular components of DOM that is, dissolved amino acids (DAA) and dissolved combined carbohydrates (DCCHO), in the upwelling region off Peru. We found the highest concentrations of DCCHO in fully oxygenated surface waters steeply declining at shallow depth. The highest DAA concentrations were observed close to the surface also, but attenuation of DAA concentration over depth was less pronounced. Compositional changes of DCCHO were strongest within more oxygenated waters. Compositional changes of DAA were also evident under suboxic conditions (<5 µmol O2 kg−1) and indicated bacterial peptide degradation. Moreover, specific free amino acids (alanine and threonine) were enhanced within suboxic waters, pointing to a potential production of dissolved organic nitrogen under suboxic conditions. Our results therewith suggest that deoxygenation supports a spatial decoupling of DCCHO and DAA production and degradation dynamics and give new insights to carbon and nitrogen cycling in the OMZ off Peru.
description: Plain Language Summary: The molecular composition of dissolved organic matter (DOM) in seawater mainly depends on production and consumption processes by plankton organisms. The biological consumption of DOM reduces the amount of oxygen in seawater, but little is known about the composition of DOM in so‐called oxygen minimum zones (OMZs). We studied the distribution of DOM, specifically of dissolved sugars and amino acids in the OMZ off Peru. We observed that the reworking and degradation of sugars and amino acids differed between more and less oxygenated waters. We also found indications for the production of specific amino acids within the OMZ. Our study therewith suggests, that oxygen concentrations affect dissolved amino acid and sugar dynamics and may help to better understand carbon and nitrogen cycling within OMZs.
description: Key Points: Decoupling of dissolved combined carbohydrates and dissolved amino acids dynamics, in the oxygen minimum zone off Peru. Free amino acids indicate production of dissolved organic nitrogen within suboxic waters.
description: Hemholtz Association
description: German Science Foundation
Convex Geometry and its Applications (hybrid meeting)
Creators: name: (:Unkn) Unknown
Publisher: name: Zürich : EMS Publ. House
Year: 2021
Subjects: subject: Konferenzschrift
subject: 510

description: The geometry of convex domains in Euclidean space plays a central role in several branches of mathematics: functional and harmonic analysis, the theory of PDE, linear programming and, increasingly, in the study of algorithms in computer science. The purpose of this meeting was to bring together researchers from the analytic, geometric and probabilistic groups who have contributed to these developments.
title: Elemental redistributions at structural defects in Cu(In,Ga)Se₂ thin films for solar cells
Creators: name: Simsek Sanli, Ekin
name: Ramasse, Quentin M.
name: Sigle, Wilfried
name: Abou-Ras, Daniel
name: Mainz, Roland
name: Weber, A.
name: Kleebe, Hans‐Joachim
name: Aken, Peter A. van
Publisher: name: AIP Publishing
Year: 2022

description: The microstructural evolution of Cu(In,Ga)Se₂ absorber layers during a three-stage-type co-evaporation process was studied to elucidate the effect of a Cu-rich stage on the formation of extended structural defects. Defect densities for two Cu-poor samples, one interrupted before and one after this crucial Cu-rich composition stage, were investigated by scanning transmission electron microscopy (STEM) imaging. The structure and chemical nature of individual defects were investigated by aberration-corrected high-resolution STEM in combination with electron energy-loss spectroscopy on the atomic-scale. In spite of the different defect densities between the two samples, most of the individual defects exhibited similar chemistry. In particular, the elemental distributions of atomic columns at {112} twin planes, which are very frequent in Cu(In,Ga)Se₂ thin films, were found to be the same as in the defect-free grain interiors. In contrast, within grain boundaries, dislocation cores, and other structurally more complex defects, elemental redistributions of Cu and In were observed.
Quantum information processing architecture with endohedral fullerenes in a carbon nanotube
Creators: name: Yang, Wan Li
name: Xu, Zhen Yu
name: Wei, Hua
name: Feng, Mang
name: Suter, Dieter
Publisher: name: arXiv
Year: 2010
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: A potential quantum information processor is proposed using a fullerene peapod, i.e., an array of the endohedral fullerenes 15N@C60 or 31P@C60 contained in a single walled carbon nanotube (SWCNT). The qubits are encoded in the nuclear spins of the doped atoms, while the electronic spins are used for initialization and readout, as well as for two-qubit operations.
description: 8 pages, 8 figures
Design of a submillimeter gas laser
Creators: name: Sahay, Vishnu
Publisher: name: University of British Columbia
Year: 2011

description: A gas laser has been designed to 01lase over the entire far infra-red spectrum. This thesis discusses the theoretical and practical considerations that are involved in such a design. The three aspects of design that are discussed are the laser cavity, the excitation mechanism, and the detection apparatus. Every effort is made throughout to keep the system as simple as possible. Water vapor is used in the laser as a test gas, since it is known to have transitions in the far infra-red region. It was found to lase in several lines most of which have been identified with lines discovered by other workers. Two lines, however, appear to be new: 133.65μ, and 145.75μ with a possible error of ±.65μ. Characteristic variations of output power with pressure and current density have been obtained for the laser using water vapor. Attempts at obtaining laser action with acetone and alcohol proved unsuccessful.
Moduli spaces and Modular forms (hybrid meeting)
Creators: name: (:Unkn) Unknown
Publisher: name: Zürich : EMS Publ. House
Year: 2021
Subjects: subject: Konferenzschrift
subject: 510

description: The relation between moduli spaces and modular forms goes back to the theory of elliptic curves. On the one hand both topics experience their own growth and development, but from time to time new unexpected links show up and usually these lead to progress on both sides. One subject where there has been a lot of progress concerns the moduli of abelian varieties and K3 surfaces and especially on the Kodaira dimension of these spaces. The idea of the workshop was to bring together the experts of the two areas in the hope that discussion, interaction and lectures would spur the development of new ideas. The lectures of the workshop gave ample evidence of the interaction and provided opportunities for further interaction. Besides the lectures participants interacted via zoom in smaller groups.
Deformation, CPO, and Elastic Anisotropy in Low‐Grade Metamorphic Serpentinites, Atlantis Massif Oceanic Core Complex
Creators: name: Kuehn, R.
name: Behrmann, J. H.
name: Stipp, M.
name: Kilian, R.
name: Leiss, B.
Publisher: name: FID GEO
Year: 2021

description: Crystallographic preferred orientation (CPO) and the associated seismic anisotropy of serpentinites are important factors for the understanding of tectonic settings involving hydrated Earth´s mantle, for example, at slow‐spreading mid‐ocean ridges. CPO of lizardite and magnetite in low‐grade metamorphic serpentinites from the Atlantis Massif oceanic core complex (Mid‐Atlantic Ridge, 30°N) were determined using synchrotron high energy X‐ray diffraction in combination with Rietveld texture analysis. Serpentinite mesh structures show weak CPO while deformed samples show a single (0001) maximum perpendicular to the foliation. Seismic anisotropies calculated from CPO show up to >11% anisotropy for compressional waves (Vp) and shear wave splitting up to 0.38 km/s in the deformed samples. This indicates that deformation in shear zones controls elastic anisotropy and highlights its importance in defining the seismic signature of hydrated upper mantle.
description: Plain Language Summary: The easy deformability of serpentinites is important in settings where tectonic plates move relative to each other. Serpentinites form when rocks which belong to the Earth's mantle get in contact with water and react. As the distribution of serpentinites within the oceanic lithosphere cannot be determined from direct observations, we can only refer to seismic data. In crystals, physical properties such as the velocity of seismic waves can vary with direction. The internal structure of a rock, a multi‐crystal material, hence provides a complex function of seismic wave velocities depending on the arrangement of these crystals. Alignment of the crystals is usually thought to be strengthened by deformation. At the Atlantis Massif (30°N, Mid‐Atlantic ridge), serpentinites were sampled by scientific ocean drilling. We analyzed the arrangement of the crystals using focused X‐rays and can distinguish different microstructures originating from different intensities of deformation. The spatial orientation of the crystals was analyzed using high‐energy X‐ray diffraction. We find different states of ordering of the crystals which we associate with different states of deformation. From those data, we can compute the seismic properties of such rocks. The findings can help to detect zones of strong deformation in the Earth's Upper Mantle.
description: Key Points: Rietveld texture analysis of low‐grade metamorphic serpentinites. Anisotropy increase with deformation intensity. Seismic anisotropy of shear zones in oceanic serpentinites.
description: Deutsche Forschungsgemeinschaft (DFG) http://dx.doi.org/10.13039/501100001659
Horizons in matter: black hole hair vs. Null Big Bang
Creators: name: Bronnikov, K. A.
name: Zaslavskii, O. B.
Publisher: name: arXiv
Year: 2009
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: It is shown that only particular kinds of matter (in terms of the "radial" pressure to density ratio $w$) can coexist with Killing horizons in black-hole or cosmological space-times. Thus, for arbitrary (not necessarily spherically symmetric) static black holes, admissible are vacuum matter ($w=-1$, i.e., the cosmological constant or some its generalization) and matter with certain values of $w$ between 0 and -1, in particular, a gas of disordered cosmic strings ($w=-1/3$). If the cosmological evolution starts from a horizon (the so-called Null Big Bang scenarios), this horizon can co-exist with vacuum matter and certain kinds of phantom matter with $w\geq -3$. It is concluded that normal matter in such scenarios is entirely created from vacuum.
description: 4 pages, essay written for the Gravity Research Foundation 2009 Awards for Essays on Gravitation, awarded a honorable mention
Mini-Workshop: Non-semisimple Tensor Categories and Their Semisimplification (online meeting)
Creators: name: (:Unkn) Unknown
Publisher: name: Zürich : EMS Publ. House
Year: 2021
Subjects: subject: Konferenzschrift
subject: 510

description: Finite tensor categories are, despite their many applications and great interest, notoriously hard to classify. Among them, the semisimple ones (called fusion categories) have been intensively studied. Those with non-integral dimensions form a remarkable class. Already more than 20 years ago, tilting modules have been proposed as a source of such fusion categories. In this way, the Verlinde categories associated to the pair of a simple complex Lie algebra $\mathfrak g$ and an integer level $k$ have been recovered in a purely algebraic framework - called semisimplification of tensor categories. Recently efforts to understand how to go beyond these examples emerged. This mini-workshop aims at bringing together experts from various branches of representation theory and topological field theory to deepen our understanding of finite tensor categories and to compare new ways to understand semisimplification.
Mini-Workshop: Nonpositively Curved Complexes (online meeting)
Creators: name: (:Unkn) Unknown
Publisher: name: Zürich : EMS Publ. House
Year: 2021
Subjects: subject: Konferenzschrift
subject: 510

description: The leading theme of the meeting was to understand nonpositively curved complexes and groups acting on them. Motivations, questions, results, and techniques being presented and discussed come from various areas of mathematics, including algebraic geometry, Lie groups, metric graph theory, geometric topology, algebraic topology, coarse geometry, $K$-theory, and, in general, geometric and analytic group theory. The subject discussed focused around participant's latest achievements, and important open questions in the area.
On the Propagation of Reaction Fronts in a Sandy Aquifer Over 20+ Years: Lessons From a Test Site in Northwestern Germany
Creators: name: Houben, Georg J.
name: Post, Vincent E. A.
name: Gröger‐Trampe, Jens
name: Pesci, María H.
name: Sültenfuß, Jürgen
Publisher: name: FID GEO
Year: 2021

description: Despite reduction measures, nitrate and aluminum concentrations remain high in aquifers in northwestern Europe. To evaluate the effectiveness of groundwater protection policies, the long‐term fate of these contaminants in groundwater needs to be understood. The groundwater catchment of the Haren water works, NW Germany, was characterized hydrogeochemically in the late 1990s, which provides an opportunity to study the solute fronts over a two‐decade period and conduct a post‐audit of the predicted front movement. Results indicate that, despite a significant reduction of the atmospheric acid loads, the acidification of soil and groundwater at the forest site persists. Removal of sorbed aluminum is required to induce a noticeable improvement, which will take at least several decades. The unexpected appearance of nitrate at the site, caused by a land use change in 1998, highlights the need for long‐term monitoring. Core data at the agricultural site show that the denitrification front has moved very little between 1998 and 2017, in accordance with previous forecasts. Denitrification by‐products, mainly sulfate and nitrogen, have migrated from the upper into the lower aquifer. A reactive transport model demonstrated how the link between the regional groundwater flow, pyrite oxidation, and the temporal variability of the nitrate concentration in recharge water, as reconstructed from age tracers, result in the observed vertical distribution of sulfate and nitrogen. This study demonstrates how long‐term monitoring, aided by model‐based data interpretation, can be used to successfully study and predict the fate of contaminants in groundwater.
description: Key Points: Position of reaction fronts for nitrate and acidification in aquifers checked after 20+ years. Acidification of soil and groundwater still strong, despite reductions of atmospheric input. Nitrate front has moved very slowly over last 20 years but denitrification products have migrated into lower aquifer.
A mechanism for switching near a heteroclinic network
Creators: name: Kirk, Vivien
name: Lane, Emily
name: Postlethwaite, Claire M.
name: Rucklidge, Alastair M.
name: Silber, Mary
Publisher: name: arXiv
Year: 2009
Subjects: subject: Chaotic Dynamics (nlin.CD)
subject: FOS: Physical sciences

description: We describe an example of a structurally stable heteroclinic network for which nearby orbits exhibit irregular but sustained switching between the various sub-cycles in the network. The mechanism for switching is the presence of spiralling due to complex eigenvalues in the flow linearised about one of the equilibria common to all cycles in the network. We construct and use return maps to investigate the asymptotic stability of the network, and show that switching is ubiquitous near the network. Some of the unstable manifolds involved in the network are two-dimensional; we develop a technique to account for all trajectories on those manifolds. A simple numerical example illustrates the rich dynamics that can result from the interplay between the various cycles in the network.
description: 37 pages, 10 figures, submitted to Dynamical Systems: An International Journal
Challenges in Optimization with Complex PDE-Systems (hybrid meeting)
Creators: name: (:Unkn) Unknown
Publisher: name: Zürich : EMS Publ. House
Year: 2021
Subjects: subject: Konferenzschrift
subject: 510

description: The workshop concentrated on various aspects of optimization problems with systems of nonlinear partial differential equations (PDEs) or variational inequalities (VIs) as constraints. In particular, discussions around several keynote presentations in the areas of optimal control of nonlinear or non-smooth systems, optimization problems with functional and discrete or switching variables leading to mixed integer nonlinear PDE constrained optimization, shape and topology optimization, feedback control and stabilization, multi-criteria problems and multiple optimization problems with equilibrium constraints as well as versions of these problems under uncertainty or stochastic influences, and the respectively associated numerical analysis as well as design and analysis of solution algorithms were promoted. Moreover, aspects of optimal control of data-driven PDE constraints (e.g. related to machine learning) were addressed.
Synchrotron Radiation from the Galactic Center in Decaying Dark Matter Scenario
Creators: name: Ishiwata, Koji
name: Matsumoto, Shigeki
name: Moroi, Takeo
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We discuss the synchrotron radiation flux from the Galactic center in unstable dark matter scenario. Motivated by the anomalous excess of the positron fraction recently reported by the PAMELA collaboration, we consider the case that the dark matter particle is unstable (and long-lived), and that energetic electron and positron are produced by the decay of dark matter. Then, the emitted electron and positron becomes the source of the synchrotron radiation. We calculate the synchrotron radiation flux for models of decaying dark matter, which can explain the PAMELA positron excess. Taking the lifetime of the dark matter of O(10^26 sec), which is the suggested value to explain the PAMELA anomaly, the synchrotron radiation flux is found to be O(1 kJy/str) or smaller, depending on the particle-physics and cosmological parameters.
description: 20 pages, 6 figures
A ∼12 Myr Miocene Record of East Asian Monsoon Variability From the South China Sea
Creators: name: Holbourn, Ann
name: Kuhnt, Wolfgang
name: Clemens, Steven C.
name: Heslop, David
Publisher: name: FID GEO
Year: 2021

description: The long‐term evolution of the East Asian Monsoon and the processes controlling its variability under changing climate boundary conditions remain enigmatic. Here, we integrate new and published high‐resolution planktic and benthic foraminiferal isotope data with proxy records for chemical weathering derived from diffuse reflectance spectroscopy at Ocean Drilling Program Site 1146 (South China Sea) to reconstruct the evolution of the summer monsoon between ∼17 and 5 Ma. Our records show that an overall warm and humid tropical climate prevailed over southeastern Asia during the Miocene Climatic Optimum, suggesting northward expansion of the tropical rain belt in response to greenhouse gas forcing. By contrast, monsoon seasonality increased during the middle Miocene Climatic Transition in tandem with Antarctic glacial expansion and global cooling. Substantial weakening of the summer monsoon between ∼12.7 and 10.9 Ma supports that decreased weathering and riverine input of nutrients and alkalinity contributed to carbonate depletion in the deep ocean during the Carbonate Crash. Intensification of monsoonal circulation and strengthening of the biological pump through the late Miocene promoted carbon burial, drawdown of atmospheric CO2, and climate cooling during the Biogenic Bloom. These results underscore the dynamic evolution of the East Asian Monsoon throughout the middle to late Miocene. Variations in local insolation forcing and in Southern Hemisphere ice volume, influencing the latitudinal thermal gradient, evaporation‐moisture budgets, and the strength of the tropical convection, exerted major controls on the development of the monsoon.
description: Key Points: Equable, warm, and humid climate over Southeast Asia during Miocene Climatic Optimum due to latitudinal expansion of tropical convection. Intensification of seasonal monsoonal regime linked to stepwise climate cooling during middle Miocene Climatic Transition. Decreased riverine input of alkalinity to ocean due to summer monsoon decline contributed to middle to late Miocene Carbonate Crash.
description: Deutsche Forschungsgemeinschaft (DFG) http://dx.doi.org/10.13039/501100001659
Spectroscopic Analysis of DA White Dwarfs: Stark Broadening of Hydrogen Lines Including Non-Ideal Effects
Creators: name: Tremblay, P. -E.
name: Bergeron, P.
Publisher: name: arXiv
Year: 2009
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: We present improved calculations for the Stark broadening of hydrogen lines in dense plasmas typical of white dwarf atmospheres. Our new model is based on the unified theory of Stark broadening from Vidal, Cooper, & Smith. For the first time, we account for the non-ideal effects in a consistent way directly inside the line profile calculations. The Hummer & Mihalas theory is used to describe the non-ideal effects due to perturbations on the absorber from protons and electrons. We use a truncation of the electric microfield distribution in the quasi-static proton broadening to take into account the fact that high electric microfields dissociate the upper state of a transition. This approach represents a significant improvement over previous calculations that relied on the use of an ad hoc parameter to mimic these non-ideal effects. We obtain the first model spectra with line profiles that are consistent with the equation of state. We revisit the properties of DA stars in the range 40,000 K > Teff > 13,000 K by analyzing the optical spectra with our improved models. The updated atmospheric parameters are shown to differ substantially from those published in previous studies, with a mean mass shifted by +0.034 Msun. We also show that these revised atmospheric parameters yield absolute visual magnitudes that remain in excellent agreement with trigonometric parallax measurements.
description: 44 pages, 14 figures, accepted for publication in the Astrophysical Journal
Dreams and well-being
Creators: name: Gilchrist, SA
Publisher: name: University Of Tasmania
Year: 2023

description: Anecdotal evidence abounds of the connection between improved well-being and understanding of one's own dreams. Unfortunately, evidence often comes from dream workers, dream interpreters, or other people with a particular interest in dreams who cannot be viewed as impartial; the evidence usually does not have a basis in scientific study. The objective of the research and studies reported in this thesis was to bring scientific rigour to the exploration of the effects of dreams on participants. This objective of robustness was achieved across three studies by using longitudinal and cross-sectional, quantitative and qualitative approaches investigating several areas: the source of dreams, contributory factors to the nature of dreams, emotions in dreams and in waking life, and methods for recording dreams. A definition of well-being had to be established, methods found for measuring well-being, methods of working with dreams both individually and in groups, and experiments devised to record any changes in affect attributable to participant's exploration of their dreams. The first study (N=123) looked at the connection between personality characteristics, waking events, thoughts and emotions, with those experienced in dreams. A strong correlation was found between the emotions experienced in waking life and those present in dreams. Only a few weak relationships were found between dream emotions and well-being measures. The second study investigated the intra-individual relationship between waking and dream emotions, using data collected from 32 participants over an eight week period. Analyses were carried out to investigate correlations between waking emotions and the dream emotions experienced that night, and between dream emotions and the waking emotions experienced the following day. The results of this study were inconclusive. The third study considered the effects of participants working in a facilitated workshop or in one-on-one sessions with a goal of making sense of their dreams in relationship to their waking life. This study provided evidence of positive changes in participant's well-being, particularly in normalisation of participant's own dreams, better insight and understanding of their own life, and increased awareness and acceptance of their own emotions. Together these studies provide support for the premise that dreams are strongly connected to waking life and that through the use of techniques to interpret and draw learning from one's dreams, an improvement in well-being can be achieved.
Demystifying Privacy in 5G Stand Alone Networks
Creators: name: Eleftherakis, Stavros
name: Otim, Timothy
name: Santaromita, Giuseppe
name: Zayas, Almudena Diaz
name: Giustiniano, Domenico
name: Kourtellis, Nicolas
Publisher: name: arXiv
Year: 2024
Subjects: subject: Networking and Internet Architecture (cs.NI)
subject: FOS: Computer and information sciences

description: Ensuring user privacy remains critical in mobile networks, particularly with the rise of connected devices and denser 5G infrastructure. Privacy concerns have persisted across 2G, 3G, and 4G/LTE networks. Recognizing these concerns, the 3rd Generation Partnership Project (3GPP) has made privacy enhancements in 5G Release 15. However, the extent of operator adoption remains unclear, especially as most networks operate in 5G Non Stand Alone (NSA) mode, relying on 4G Core Networks. This study provides the first qualitative and experimental comparison between 5G NSA and Stand Alone (SA) in real operator networks, focusing on privacy enhancements addressing top eight pre-5G attacks based on recent academic literature. Additionally, it evaluates the privacy levels of OpenAirInterface (OAI), a leading open-source software for 5G, against real network deployments for the same attacks. The analysis reveals two new 5G privacy vulnerabilities, underscoring the need for further research and stricter standards.
description: 16 pages, 6 Figures, 1 table, In ACM MobiCom 2024
Manifolds and Groups
Creators: name: (:Unkn) Unknown
Publisher: name: Zürich : EMS Publ. House
Year: 2020
Subjects: subject: Konferenzschrift
subject: 510

description: The workshop concentrated on the interplay of advances in the understanding of manifolds and geometric group theory. In particular, we discussed mapping class groups and moduli spaces of manifolds (also of high dimension) and aspects of homological stability related to them; cobordism categories and their applications; $L^2$-invariants, simplicial volume, and their applications; and in general, the phenomena of rigidity versus flexibility in geometry and topology.
Deep Emulators for Differentiation, Forecasting, and Parametrization in Earth Science Simulators
Creators: name: Nonnenmacher, Marcel
name: Greenberg, David S.
Publisher: name: FID GEO
Year: 2021

description: To understand and predict large, complex, and chaotic systems, Earth scientists build simulators from physical laws. Simulators generalize better to new scenarios, require fewer tunable parameters, and are more interpretable than nonphysical deep learning, but procedures for obtaining their derivatives with respect to their inputs are often unavailable. These missing derivatives limit the application of many important tools for forecasting, model tuning, sensitivity analysis, or subgrid‐scale parametrization. Here, we propose to overcome this limitation with deep emulator networks that learn to calculate the missing derivatives. By training directly on simulation data without analyzing source code or equations, this approach supports simulators in any programming language on any hardware without specialized routines for each case. To demonstrate the effectiveness of our approach, we train emulators on complete or partial system states of the chaotic Lorenz‐96 simulator and evaluate the accuracy of their dynamics and derivatives as a function of integration time and training data set size. We further demonstrate that emulator‐derived derivatives enable accurate 4D‐Var data assimilation and closed‐loop training of parametrizations. These results provide a basis for further combining the parsimony and generality of physical models with the power and flexibility of machine learning.
description: Plain Language Summary: Many Earth science simulators are implemented as monolithic programs that calculate changes in the state of a system over time. In many cases, using or improving these simulators also requires the derivatives of their outputs with respect to inputs, which describe how future states depend on past states. These derivatives can be difficult or costly to compute. Several recent studies have applied deep learning (DL) to simulation data to construct emulators of their dynamics. Here, we use the fact that DL models can be easily and automatically differentiated to obtain approximate derivatives of the original simulator and test this idea on a simple and common chaotic model of the atmosphere. We verify in several experiments that the emulator derivatives, which require neither additional training nor extensive postprocessing to obtain, can indeed be used as a valid substitute for the derivatives of the simulator.
description: Key Points: Deep learning models trained on simulation data can learn the dynamics of Earth science simulators. Deep learning models also learn the input–output derivatives of the state‐update function, which are unavailable for many simulators. We show on Lorenz‐96 that these learned derivatives can be used directly for data assimilation and parametrization tuning.
Field study of the distribution and behavior of Oligocottus maculosus Girard : a tidepool cottid of the northeast Pacific Ocean
Creators: name: Green, John Marshall
Publisher: name: University of British Columbia
Year: 2011

description: The study was concerned first of all with the distribution pattern at low tide of Oligocottus maculosus Girard and other cottid fishes inhabiting tidepools on the west coast of Vancouver Island, B.C. Five species (O. maculosus, G. remensis, Clinocottus acuticeps, C. einbryum and C. globiceps) have their centers of distribution in the intertidal zone. Seven species (Hemilepidotus hernilepidotus, Artedius lateralis, A. fenestralis, Ascelichthys rhodorus, O. snyderi, Enophrys bison and Leptocottus armatus) inhabit tidepools but are most abundant in the subtidal zone. O. maculosus is the most abundant and widely distributed tide-pool cottid in the intertidal zone. Only three other species (C. acuticeps, C. embryum and C. globiceps) regularly inhabit tidepools above LLHW (lowest lower high water). The primary environmental factor correlated with the distribution of O. maculosus is exposure to wave action. In exposed transects this species is restricted to the upper intertidal zone, while in sheltered transects it inhabits tidepools throughout the intertidal zone. Observations show that O. maculosus responds to water turbulence by retreating to cover. It is concluded that to inhabit a given tidcpool O. maculosus must have a minimum period of low turbulent conditions. This species has 'capitalized' on the tidcpool habitat to invade the open coast environment. The study's second concern was to determine the fidelity of individual O. maculosus to the tidcpool in which they are found. O. maculosus shows fidelity to specific tidepools and will return to these pools when displaced from them. The results indicate that the navigational ability of O. maculosus is not solely dependent upon familiarity .with geographical features of the intertidal zone. It is suggested that homing behavior functions as a mechanism stabilizing the spatial distribution of this species. Thirdly, the study was concerned with determining what factors affect the field activity such as feeding and spawning of O. maculosus, and a comparison of its field activity to that under controlled conditions. In the natural habitat its activity is dependent primarily upon such factors as turbulence, temperature and light. Field observations on feeding behavior support Morris1 (I960) conclusion, drawn from physiological studies, that approximately the 16°C isotherm is the limiting environmental factor in the southward distribution of this species. Under constant conditions O. maculosus exhibits a tidal rhythm of locomotor activity. The characteristics of the rhythm indicate that it is entrained directly by the tide. Hydrostatic pressure is suggested as the possible synchronizer. The rhythm is not directly related to the field activity of O. maculosus. It is concluded that it represents the coupling of an avoidance or escape response to a biological clock. Such a mechanism would function with, and be partially responsible for, the homing behavior.
A Covariant Form of the Navier-Stokes Equation for the Galilean Conformal Algebra
Creators: name: Mukhopadhyay, Ayan
Publisher: name: arXiv
Year: 2009
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We demonstrate that the Navier-Stokes equation can be covariantized under the full infinite dimensional Galilean Conformal Algebra (GCA), such that it reduces to the usual Navier-Stokes equation in an inertial frame. The covariantization is possible only for incompressible flows, i.e when the divergence of the velocity field vanishes. Using the continuity equation, we can fix the transformation of pressure and density under GCA uniquely. We also find that when all chemical potentials vanish, $c_{s}$, which denotes the speed of sound in an inertial frame comoving with the flow, must either be a fundamental constant or given in terms of microscopic parameters. We will discuss how both could be possible. In absence of chemical potentials, we also find that the covariance under GCA implies that either the viscosity should vanish or the microscopic theory should have a length scale or a time scale or both. We further find that the higher derivative corrections to the Navier-Stokes equation, can be covariantized, only if they are restricted to certain possible combinations in the inertial frame. We explicitly evaluate all possible three derivative corrections. Finally, we argue that our analysis hints that the parent relativistic theory with relativistic conformal symmetry needs to be deformed before the contraction is taken to produce a sensible GCA invariant dynamical limit.
description: 33 pages; accepted for publication in JHEP
Gewöhnliche Differentialgleichungen: Harmonic, Subharmonic, Homoclinic, and Heteroclinic Solutions
Creators: name: (:Unkn) Unknown
Publisher: name: Oberwolfach-Walke : Mathematisches Forschungsinstitut Oberwolfach
Year: 1999
Subjects: subject: Konferenzschrift
subject: 510

description: [no abstract available]
Factors Affecting Spatial and Temporal Variability of Metals in Drainage Water from Arable Fields
Creators: name: Baborowski, Martina
name: Rupp, Holger
name: Wendt‐Potthoff, Katrin
name: Tauchnitz, Nadine
name: Meissner, Ralph
Publisher: name: FID GEO
Year: 2021

description: Respecting fertilizer application, the metal content in drainage water is studied under conventional agricultural management from 2013 to 2014 in two adjacent fields located in the North German Plain. Findings are compared with data of nutrients, main ions, and dissolved organic carbon, as well as element contents in fertilizers and geogenic background values of soils. Comparatively low metal concentrations are found in drainage water. These results are in line with metal contents of applied mineral fertilizers, of cattle slurry, and random analysis of the two soils considered. Relating to effective ordinances, the applied fertilizers occasionally pose a risk for the groundwater or downstream water bodies. Concentrations of some metals (Al, Co, Cr, Pb, and V) are rather affected by soil erosion than by fertilizers. Besides fertilizers and soil erosion, mainly pedo‐hydrological conditions, which differ between the two fields, influence element profiles in tile drainage by the extent of anoxia and subsequent denitrification and sulfate reduction. Against the background of climate change, further investigations with respect to possible changes in soil water budget are necessary.
description: Variability of metals in drainage water from arable fields is investigated. Drainage improves topsoil conditions by amelioration. It also may aggravate diffuse pollution by shortening residence time of water in soil. In the study, besides fertilizers and soil erosion, mainly pedo‐hydrological conditions influence metal concentrations in tile drainage. Measures to minimize soil erosion should supplement careful use of fertilizers.
description: German Federal Environmental Foundation (DBU)
Analogue Gravity and ultrashort laser pulse filamentation
Creators: name: Faccio, D.
name: Cacciatori, S.
name: Gorini, V.
name: Sala, V. G.
name: Averchi, A.
name: Lotti, A.
name: Kolesik, M.
name: Moloney, J. V.
Publisher: name: arXiv
Year: 2009
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: Ultrashort laser pulse filaments in dispersive nonlinear Kerr media induce a moving refractive index perturbation which modifies the space-time geometry as seen by co-propagating light rays. We study the analogue geometry induced by the filament and show that one of the most evident features of filamentation, namely conical emission, may be precisely reconstructed from the geodesics. We highlight the existence of favorable conditions for the study of analogue black hole kinematics and Hawking type radiation.
description: 4 pages, revised version
Nigerian English and National Identity
Creators: name: Ugwuanyi, Kingsley
Publisher: name: Zenodo
Year: 2020

description: Note: This talk has not gone through a process of peer review, and findings should therefore be treated as preliminary and subject to change. SOAS Linguistics Webinars
 Summer 2020
 August 11 Kingsley Ugwuanyi (Northumbria University) Abstract: It has been argued, especially in the non-inner circles (NICs) of English, that the extent to which speakers of English consider English as a ‘harbinger’ of their national identity might determine how they position as ‘owners’ of that language. Although findings suggest a widespread awareness as well as acceptance of endonormative varieties of English in NICs, it has yet to be widely debated whether perceptions of English as expressive of national identity in NICs might allow for its possible consideration as a ‘national language’. In this talk, I will present findings from a larger study of perceptions of Nigerian English to demonstrate how speakers of English in Nigeria enact a sense of national identity in their perceptions of English language (ownership).
CUDAEASY - a GPU Accelerated Cosmological Lattice Program
Creators: name: Sainio, Jani
Publisher: name: arXiv
Year: 2009
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: Computational Physics (physics.comp-ph)
subject: FOS: Physical sciences

description: This paper presents, to the author's knowledge, the first graphics processing unit (GPU) accelerated program that solves the evolution of interacting scalar fields in an expanding universe. We present the implementation in NVIDIA's Compute Unified Device Architecture (CUDA) and compare the performance to other similar programs in chaotic inflation models. We report speedups between one and two orders of magnitude depending on the used hardware and software while achieving small errors in single precision. Simulations that used to last roughly one day to compute can now be done in hours and this difference is expected to increase in the future. The program has been written in the spirit of LATTICEEASY and users of the aforementioned program should find it relatively easy to start using CUDAEASY in lattice simulations. The program is available at http://www.physics.utu.fi/theory/particlecosmology/cudaeasy/ under the GNU General Public License.
description: 10 pages, 10 figures
Thermal van der Waals Interaction between Graphene Layers
Creators: name: Gómez-Santos, G.
Publisher: name: arXiv
Year: 2009
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Other Condensed Matter (cond-mat.other)
subject: FOS: Physical sciences

description: The van de Waals interaction between two graphene sheets is studied at finite temperatures. Graphene's thermal length $(ξ_T = \hbar v / k_B T)$ controls the force versus distance $(z)$ as a crossover from the zero temperature results for $z\ll ξ_T$, to a linear-in-temperature, universal regime for $z\gg ξ_T$. The large separation regime is shown to be a consequence of the classical behavior of graphene's plasmons at finite temperature. Retardation effects are largely irrelevant, both in the zero and finite temperature regimes. Thermal effects should be noticeable in the van de Waals interaction already for distances of tens of nanometers at room temperature.
description: enlarged version, 9 pages, 4 figures, updated references
Potential of a Gravity‐Driven Film Flow Model to Predict Infiltration in a Catchment for Diverse Soil and Land Cover Combinations
Creators: name: Demand, D.
name: Weiler, M.
Publisher: name: FID GEO
Year: 2021

description: Applying physically based models that include preferential flow (PF) is still very challenging at the catchment scale. A gravity‐driven film flow approach could be a promising concept for modeling PF as it only requires a small number of parameters. We tested if this approach can be used for different soils and land covers within a 247 km2 catchment and if we can find generalizable relationships of the film flow parameters to site or rainfall properties. We used a unique data set from a soil moisture sensor network with 135 instrumented soil profiles in three different geologies (slate, marl, and sandstone) and two land covers (forest and grassland) and fitted the film flow model to around 1,700 infiltration events. The results demonstrate that the physical relationship of film flow was capable to predict wetting front velocity (v) and flow parameters from rainfall input (qs) alone. This relationship was pronounced in grassland sites but weaker for forest sites, probably due to heterogeneity of the rainfall input underneath the canopy. Incorporating the water content into the v‐qs relationship did not improve the quality, but showed that for the film flow the rainfall input and hence gravity is in fact the dominant driver and not capillarity. Furthermore, abstraction of water into the soil matrix during film flow is an important process to be included into the framework with reasonable agreements for marl and sandstone using a multiple linear regression. Film flow and corresponding functional parameter relationships for other regions could improve catchment wide PF modeling in the future.
description: Key Points: Gravity‐driven film flow has a large potential to describe preferential flow during natural infiltration events at a diversity of sites. Parameters can be determined from the rainfall input, which has a stronger effect on the flow velocity than initial soil water content. Abstraction of water from film flow in macropores into the soil matrix is a process that has to be included in more detail.
description: Deutsche Forschungsgemeinschaft (DFG) http://dx.doi.org/10.13039/501100001659
Angular correlations in the cosmic gamma-ray background from dark matter annihilation around intermediate-mass black holes
Creators: name: Taoso, Marco
name: Ando, Shin'ichiro
name: Bertone, Gianfranco
name: Profumo, Stefano
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Dark matter (DM) annihilation could in principle contribute to the diffuse cosmic gamma-ray back- ground (CGB). While with standard assumptions for cosmological and particle physics parameters this contribution is expected to be rather small, a number of processes could boost it, including a larger-than-expected DM annihilation cross-section, or the occurance of DM substructures such as DM mini-spikes around intermediate-mass black holes. We show that angular correlations of the CGB provide a tool to disentangle the signal induced by DM annihilation in mini-spikes from a conventional astrophysical component. Treating blazars as a known background, we study the prospects for detecting DM annihilations with the Fermi Gamma-Ray Space Telescope for different choices of DM mass and annihilation channels.
description: 13 pages, 11 figures
Wilderness : nature out of control
Creators: name: Scotney, RJ
Publisher: name: University Of Tasmania
Year: 2023

description: This thesis attempts to answer the question, \what is wilderness?\" It argues that throughout history wilderness and human habitation and modifications of it have coexisted and wilderness has been thought of as both a place of danger and one of refuge transformation and empowerment. This contradicts both the American so-called \"Received Wilderness Idea\" of wilderness as necessarily uninhabited and significantly unmodified by human beings and critiques of the entire idea of wilderness as a mere cultural construct that does not reflect physical reality. The \"Received Wilderness Idea\" has been extremely influential for policy and its application to wilderness preservation across the globe has caused the sometimes violent displacement of human populations with sometimes tragic consequence. Its implementation has also even in some cases damaged the biodiversity it sought to protect. Yet many contemporary definitions of wilderness in theory and practice acknowledge its histories of indigenous occupation. It is found that many of these definitions remain however arbitrary and equivocal. It is proposed that wilderness be defined as the kind of environment where nature is out of human control as the dominant shaping factor. In order to overcome the problem of confusion with and attachment to the Received Wilderness Idea an enquiry is made into what we mean by \"nature\" and the ways in which nature is out of our control. This enquiry reveals the wildness not only of wilderness but of the human world and human existence a discovery that allows us to transform ourselves and our environments by letting go of the illusions of control that are destroying wilderness biodiversity and human potential."