cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Crop yield estimation in the Canadian Prairies : assessing the relative importance of scale, satellite and biophysical data
Creators: name: Gogoi, Jumi
Publisher: name: University of British Columbia
Year: 2024

description: Crop production plays an important role in the Canadian Prairie economy. Crop yield models based on satellite data offer promise for obtaining consistent yield estimates across large regions. With the growing availability of observational yield data, mostly at coarser spatial scales, linear regression models have been a popular modeling tool in Canadian agriculture. Using historical crop yields from two spatial scales for key crops in the Canadian Prairies, this dissertation evaluates how to improve satellite-based yield estimation models by incorporating biophysical data and using new modeling algorithms. First, I developed linear regression models for the Canadian Prairies (Alberta, Saskatchewan, Manitoba) using satellite data for historical yield estimation using municipality scale data for model training. Vegetation indices derived from different satellite datasets (Terra-MODIS, Landsat 7&8, Sentinel-2) were tested. I found that a single vegetation index model could perform as well as a model trained using multiple different vegetation indices as long as the right vegetation index was identified for the purpose. This highlights the critical need to identify the target application and corresponding sensor-specific vegetation index/indices. Second, using the same municipality scale data, I investigated how the addition of weather data to a vegetation index-based model influences estimation accuracy. I also compared the performance of multiple linear regression to machine learning. I found that combining weather data with vegetation indices within a machine learning approach improved estimation accuracy by 3-5% across crops compared to linear regression using satellite data alone. Third, I developed a crop yield prediction model calibrated using sub-field-scale yields from one farm in the Canadian Prairies. I assessed the performance of machine and deep learning models and different combinations of satellite and biophysical data. I found that Random Forests using optimal inputs improved prediction accuracy by 7-8% across crops compared to linear regression using only vegetation indices. An application of the optimal model in within-season forecasting mode showed that end-of-season yield forecasts stabilized within three months of lead time for canola and wheat. The findings of this dissertation demonstrate the potential of additional biophysical inputs and non-linear machine learning models for improving crop yield estimation and forecasting.
Evidence for the eta_b(1S) Meson in Radiative Upsilon(2S) Decay
Creators: name: The BABAR Collaboration
name: Aubert, B.
Publisher: name: arXiv
Year: 2009
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: We have performed a search for the eta_b(1S) meson in the radiative decay of the Upsilon(2S) resonance using a sample of 91.6 million Upsilon(2S) events recorded with the BABAR detector at the PEP-II B factory at the SLAC National Accelerator Laboratory. We observe a peak in the photon energy spectrum at E_gamma = 609.3 {+4.6} {-4.5} (stat) +/- 1.9 (syst) MeV, corresponding to an eta_b(1S) mass of 9394.2 {+4.8} {-4.9} (stat) +/- 2.0 (syst) MeV/c^2. The branching fraction for the decay Upsilon(2S) --> gamma eta_b(1S) is determined to be [3.9 +/-1.1 (stat) {+1.1} {-0.9} (syst)] x 10^(-4). We find the ratio of branching fractions B[Upsilon(2S) --> gamma eta_b(1S)]/B[Upsilon(3S) --> gamma eta_b(1S)] = 0.82 +/- 0.24 (stat) {+0.20}{-0.19} (syst).
description: 7 pages, 2 figures; published version
Investigating the boundary conditions of the production effect with alphanumeric-type non-words
Creators: name: Pickering, BK
Publisher: name: University of Tasmania
Year: 2024

description: The production effect is a robust memory phenomenon where words that are read aloud are more likely to be remembered that words read silently. To date, all investigation of if the production effect extends to non-words has used phonetically legal non-words that sound like words. In this study I presented participants (N=15, M=37.7 years) with alphanumeric-type non-words, new type of non-word that lacks semantic meaning and is unpronounceable, to investigate if the production effect extends to words that do not sound like words, in a within-subjects design, replicating the methodology of MacLeod et al. (2010). Analysis of Variance (ANOVA) and follow up paired samples t-tests revealed participants in my sample did not discriminate between alphanumeric-type non-word stimuli they had seen previously and new foils, and a statistically significant effect of production for words read aloud compared to words read silently was not observed. Alphanumeric-type non-word stimuli may lack distinctiveness, or increase task complexity, moderating the production effect. Future research of the production effect may benefit from further investigation of task complexity.
On the lapse contour in the gravitational path integral
Creators: name: Banihashemi, Batoul
name: Jacobson, Ted
Publisher: name: arXiv
Year: 2024
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: The gravitational path integral is usually implemented with a covariant action by analogy with other gauge field theories, but the gravitational case is different in important ways. A key difference is that the integrand has an essential singularity, which occurs at zero lapse where the spacetime metric degenerates. The lapse integration contour required to impose the local time reparametrization constraints must run from $-\infty$ to $+\infty$, yet must not pass through zero. This raises the question: what is the correct integration contour, and why? We study that question by starting with the reduced phase space path integral, which involves no essential singularity. We observe that if the momenta are to be integrated before the lapse, to obtain a configuration space path integral, the lapse contour should pass below the origin in the complex lapse plane. This contour is also consistent with the requirement that quantum field fluctuation amplitudes have the usual short distance vacuum form, and with obtaining the Bekenstein-Hawking horizon entropy from a Lorentzian path integral. We close with a discussion of related issues, including potential obstacles to deriving a nonperturbative covariant gravitational path integral.
description: 7 pages; v2: added comments on related prior work and gauge accessibility; v3: numerous edits for clarification, revised discussion of the issue of existence of a covariant path integral, title changed from "On the lapse contour", published version
Bayesian Learning-driven Prototypical Contrastive Loss for Class-Incremental Learning
Creators: name: Raichur, Nisha L.
name: Heublein, Lucas
name: Feigl, Tobias
name: Rügamer, Alexander
name: Mutschler, Christopher
name: Ott, Felix
Publisher: name: arXiv
Year: 2024
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: Artificial Intelligence (cs.AI)
subject: FOS: Computer and information sciences
subject: G.3; I.2.4; I.2.6
subject: 62P30, 68T30, 68T05, 68T37

description: The primary objective of methods in continual learning is to learn tasks in a sequential manner over time (sometimes from a stream of data), while mitigating the detrimental phenomenon of catastrophic forgetting. This paper proposes a method to learn an effective representation between previous and newly encountered class prototypes. We propose a prototypical network with a Bayesian learning-driven contrastive loss (BLCL), tailored specifically for class-incremental learning scenarios. We introduce a contrastive loss that incorporates novel classes into the latent representation by reducing intra-class and increasing inter-class distance. Our approach dynamically adapts the balance between the cross-entropy and contrastive loss functions with a Bayesian learning technique. Experimental results conducted on the CIFAR-10, CIFAR-100, and ImageNet100 datasets for image classification and images of a GNSS-based dataset for interference classification validate the efficacy of our method, showcasing its superiority over existing state-of-the-art approaches. Git: https://gitlab.cc-asp.fraunhofer.de/darcy_gnss/gnss_class_incremental_learning
description: 27 pages, 22 figures
Additional file 4 of Transcriptional differentiation driving Cucumis sativus–Botrytis cinerea interactions based on the Skellam model and Bayesian networks
Creators: name: Zhang, Qi
name: Li, Kaihang
name: Yang, Yan
name: Li, Beibei
name: Jiang, Libo
name: He, Xiaoqing
name: Jin, Yi
name: Zhao, Guozhu
Publisher: name: figshare
Year: 2021
Subjects: subject: Genetics
subject: FOS: Biological sciences

description: Additional file 4: Table S4. Significantly enriched KEGG pathways of DEGs in B. cinerea.
Trophic partitioning among three meso-predator shark species inhabiting the Northern Adriatic Sea
Creators: name: Finotto, Licia
name: Berto, Daniela
name: Rampazzo, Federico
name: Raicevich, Saša
name: Bonanomi, Sara
name: Mazzoldi, Carlotta
Publisher: name: figshare
Year: 2023
Subjects: classificationCode: 319999
subject: Other biological sciences not elsewhere classified
classificationCode: 410203
subject: Ecosystem function

description: While the general diet of Mediterranean elasmobranchs is well studied, little is known on food partitioning and competition among sympatric species, despite these being important forces structuring marine communities. Using stomach content and stable isotope analyses, we investigated diet and trophic level and evaluated diet overlap and partitioning of Scyliorhinus canicula, Mustelus mustelus, and M. punctulatus in the northern Adriatic Sea.
Further evidence for the $Σ^{*}$ resonance with $J^P=1/2^-$ around 1380 MeV
Creators: name: Wu, Jia-Jun
name: Dulat, S.
name: Zou, B. S.
Publisher: name: arXiv
Year: 2009
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: The unquenched quark models predict the new particle $Σ^*$ with spin parity $J^P=1/2^-$ and its mass is around the well established $Σ^*(1385)$ with $J^P=3/2^+$. Here by using the effective Lagrangian approach we study \kp\ reaction at the range of $Λ^{*}(1520)$ peak, comparing the resulting total cross section, and $π^+π^-$, $Λπ^+$, $Λπ^-$ invariant squared mass distributions for various incident $K^-$ momenta, as well as the production angular distribution of the $Λ$ with the data from the Lawrence Berkeley Laboratory 25-inch hydrogen bubble chamber, we find that, apart from the existing resonance $Σ^{*}(1385)$ with $J^P=3/2^+$, there is a strong evidence for the existence of the new resonance $Σ^{*}$ with $J^P=1/2^-$ around 1380 MeV. Higher statistic data on relevant reactions are needed to clarify the situation.
description: 15 pages, 40 figures
Trophic partitioning among three mesopredatory shark species inhabiting the north-western Adriatic Sea
Creators: name: Finotto, Licia
name: Berto, Daniela
name: Rampazzo, Federico
name: Raicevich, Saša
name: Bonanomi, Sara
name: Mazzoldi, Carlotta
Publisher: name: figshare
Year: 2023
Subjects: classificationCode: 319999
subject: Other biological sciences not elsewhere classified
classificationCode: 410203
subject: Ecosystem function

description: While the general diet of Mediterranean elasmobranchs is well studied, little is known on food partitioning and competition among sympatric species, despite these being important forces structuring marine communities. Using stomach content and stable isotope analyses, we investigated diet and trophic level and evaluated diet overlap and partitioning of Scyliorhinus canicula, Mustelus mustelus, and M. punctulatus in the northern Adriatic Sea.
Two Langevin equations in the Doi-Peliti formalism
Creators: name: Itakura, Kazunori
name: Ohkubo, Jun
name: Sasa, Shin-ichi
Publisher: name: arXiv
Year: 2009
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: A system-size expansion method is incorporated into the Doi-Peliti formalism for stochastic chemical kinetics. The basic idea of the incorporation is to introduce a new decomposition of unity associated with a so-called Cole-Hopf transformation. This approach elucidates a relationship between two different Langevin equations; one is associated with a coherent-state path-integral expression and the other describes density fluctuations. A simple reaction scheme $X \rightleftarrows X+X$ is investigated as an illustrative example.
description: 14pages
New results for Petrov type D pure radiation fields
Creators: name: De Groote, Liselotte
name: Bergh, Norbert Van den
Publisher: name: arXiv
Year: 2008
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We present a new family of Petrov type D pure radiation spacetimes with a shear-free, non-diverging geodesic principal null congruence.
description: 4 pages; changed the appearance of some v's and nu's
Magnetic properties of a strongly correlated system on the Bethe lattice
Creators: name: Mancini, F. P.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We study the influence of an external magnetic field h on the phase diagram of a system of Fermi particles living on the sites of a Bethe lattice with coordination number z and interacting through on-site U and nearest-neighbor V interactions. This is a physical realization of the extended Hubbard model in the narrow-band limit. Our results establish that the magnetic field may dramatically affect the critical temperature below which a long-range charge ordered phase is observed, as well as the behavior of physical quantities, inducing, for instance, magnetization plateaus in the magnetization curves. Relevant thermodynamic quantities - such as the specific heat and the susceptibility - are also investigated at finite temperature by varying the on-site potential, the particle density and the magnetic field.
description: 7 pages, 4 figures. Statistical Physics: Modern Trends and Applications (Lviv) Conference proceedings
Post-Quantum Security: Origin, Fundamentals, and Adoption
Creators: name: Barzen, Johanna
name: Leymann, Frank
Publisher: name: arXiv
Year: 2024
Subjects: subject: Cryptography and Security (cs.CR)
subject: Quantum Physics (quant-ph)
subject: FOS: Computer and information sciences
subject: FOS: Physical sciences

description: Nowadays, predominant asymmetric cryptographic schemes are considered to be secure because discrete logarithms are believed to be hard to be computed. The algorithm of Shor can effectively compute discrete logarithms, i.e. it can brake such asymmetric schemes. But the algorithm of Shor is a quantum algorithm and at the time this algorithm has been invented, quantum computers that may successfully execute this algorithm seemed to be far out in the future. The latter has changed: quantum computers that are powerful enough are likely to be available in a couple of years. In this article, we first describe the relation between discrete logarithms and two well-known asymmetric security schemes, RSA and Elliptic Curve Cryptography. Next, we present the foundations of lattice-based cryptography which is the bases of schemes that are considered to be safe against attacks by quantum algorithms (as well as by classical algorithms). Then we describe two such quantum-safe algorithms (Kyber and Dilithium) in more detail. Finally, we give a very brief and selective overview of a few actions currently taken by governments and industry as well as standardization in this area. The article especially strives towards being self-contained: the required mathematical foundations to understand post-quantum cryptography are provided and examples are given.
description: Version 2: Reflecting progression of NIST standardization as well as governmental actions
Meson wave function from holographic models
Creators: name: Vega, Alfredo
name: Schmidt, Ivan
name: Branz, Tanja
name: Gutsche, Thomas
name: Lyubovitskij, Valery
Publisher: name: arXiv
Year: 2009
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We consider the light-front wave function for the valence quark state of mesons using the AdS/CFT correspondence, as has been suggested by Brodsky and Teramond. Two kinds of wave functions, obtained in different holographic Soft-Wall models, are discussed.
description: 8 pages
Developing a self-driving robotic platform for rapid screening of solid purification methods
Creators: name: Depner, Noah Brendan
Publisher: name: University of British Columbia
Year: 2024

description: Crystallization is a highly effective method of both isolating and purifying a compound of interest following synthesis. In industry, the development of a crystallization method is a time and labor-intensive process, often requiring a significant amount of impure solid and a strong understanding of the many factors that complicate crystallization processes. Due to these limitations, crystallization design may not be feasible in time or material-limited situations. In this thesis, I outline the development of a self-driving platform that can rapidly screen purification attempts on an impure solid. The platform autonomously collects solubility information and conducts crystallization and washing experiments on the solid, evaluating the yield, purity, and impurity rejection from each attempt. The solvent system is the primary variable screened by the platform. Following a decision tree, a user will arrive at a potential purification method for the process solid, requiring minimal characterization of impurities and using significantly less material than a traditional high-throughput screen. The platform itself is highly modular and reconfigurable; important considerations for integrating filtration, agitation and analytical modules are discussed in detail. Three industry-relevant solids were used to demonstrate the ability of the platform to model solubility data and acquire reproducible data on crystallizations and washing experiments. In one of these case studies, the full decision tree was used to successfully find high-purity crystallization conditions. Information about the impurity profile of the solid is another important factor in designing a purification. The platform is able to autonomously conduct powder dissolution studies on a solid, identifying the retention mechanism for each impurity. This was successfully demonstrated on one test system and three industry-relevant solids, identifying impurity retention mechanisms across a range of categories. Development of the platform is still in progress; future directions are outlined for integrating machine learning abilities, fully automating all decision points, and increasing robustness and accessibility.
On Necessary and Sufficient Number of Cops in the Game of Cops and Robber in Multidimensional Grids
Creators: name: Bhattacharya, Sayan
name: Paul, Goutam
name: Sanyal, Swagato
Publisher: name: arXiv
Year: 2009
Subjects: subject: Discrete Mathematics (cs.DM)
subject: FOS: Computer and information sciences

description: We theoretically analyze the Cops and Robber Game for the first time in a multidimensional grid. It is shown that for an $n$-dimensional grid, at least $n$ cops are necessary to ensure capture of the robber. We also present a set of cop strategies for which $n$ cops are provably sufficient to catch the robber. Further, for two-dimensional grid, we provide an efficient cop strategy for which the robber is caught even by a single cop under certain conditions.
description: This is a revised and extended version of the poster paper with the same title that has been presented in the 8th Asian Symposium on Computer Mathematics (ASCM), December 15-17, 2007, Singapore
On models of non-Eucludian spaces generated by associative algebras
Creators: name: Trnkova, Maria
Publisher: name: arXiv
Year: 2009
Subjects: subject: Differential Geometry (math.DG)
subject: FOS: Mathematics
subject: 53A35, 53A20, 53A30, 55R10

description: We present the non-trivial example how to generate non-Euclidean geometries from associative unital algebras. We consider bundles of the sphere of the degenerate non-Eucleadian space and its two models. The first (conformal) model is obtained by the mapping S onto a plane pass through the origin. It is analogous to the stereographic mapping. The second model (projective) is con- structed by the Norden normalization method, where we project the sphere onto a plane of normalization defining the metric and Christoffel symbols which allow us to find geodesic curves.
description: 11 pages, 1 figure; extended version of 0809.0946
Rotochemical heating with a density-dependent superfluid energy gap in neutron stars
Creators: name: González-Jiménez, Nicolás
name: Petrovich, Cristóbal
name: Reisenegger, Andreas
Publisher: name: arXiv
Year: 2010
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: When a rotating neutron star loses angular momentum, the reduction of the centrifugal force makes it contract. This perturbs each fluid element, raising the local pressure and originating deviations from beta equilibrium, inducing reactions that release heat (rotochemical heating). This effect has previously been studied by Fernández and Reisenegger for neutron stars of non-superfluid matter and by Petrovich and Reisenegger for superfluid matter, finding that the system in both cases reaches a quasi-steady state, corresponding to a partial equilibration between compression, due to the loss of angular momentum, and reactions that try to restore the equilibrium. However, Petrovich and Reisenegger assumes a constant value of the superfluid energy gap, whereas theoretical models predict density-dependent gap amplitudes, and therefore gaps that depend on the location in the star. In this work, we try to discriminate between several proposed gap models, comparing predicted surface temperatures to the value measured for the nearest millisecond pulsar, J0437-4715.
description: 2 pages, 1 figure. VIII Symposium in Nuclear Physics and Applications: Nuclear and Particle Astrophysics. Appearing in the American Institute of Physics (AIP) conference proceedings.
title: The Impact of Segregated Diversity on the Code of the Street: An Analysis of Violence-related Norms in Selected Post-Industrial Neighborhoods in Germany
Creators: name: Kurtenbach, Sebastian
name: Rauf, Abdul
Publisher: name: Institute for Interdisciplinary Conflict and Violence Research, Bielefeld University
Year: 2019
Subjects: youth violence, diversity, code of the street, urban sociology, Germany

description: Youth violence remains a concern in Germany, particularly in specific “risky” neighborhoods that tend to be socially segregated and ethnically diverse. In this paper we critically compare the results of twenty-seven qualitative interviews conducted in three risky neighborhoods in the German Ruhr area with the code of the street. While this theoretical framework is frequently cited in explaining youth violence, it was based on research in an ethnically homogenous neighborhood in the United States and thus does not engage with questions of diversity. Our findings show that the core of the code of the street is also applicable in heterogeneous contexts, thus extending the generalizability of the theoretical framework. Manifestations of manhood, reputation, and symbolic power were found to be major elements of street culture, although characterized somewhat differently than in the original work.
description: International Journal of Conflict and Violence (IJCV), Vol 13 (2019)
Alternative derivation of the relativistic contribution to perihelic precession
Creators: name: Lemmon, Tyler J.
name: Mondragon, Antonio R.
Publisher: name: arXiv
Year: 2009
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: An alternative derivation of the first-order relativistic contribution to perihelic precession is presented. Orbital motion in the Schwarzschild geometry is considered in the Keplerian limit, and the orbit equation is derived for approximately elliptical motion. The method of solution makes use of coordinate transformations and the correspondence principle, rather than the standard perturbative approach. The form of the resulting orbit equation is similar to that derived from Newtonian mechanics and includes first-order corrections to Kepler's orbits due to general relativity. The associated relativistic contribution to perihelic precession agrees with established first-order results. The reduced radius for the circular orbit is in agreement to first-order with that calculated from the Schwarzschild effective potential. The method of solution is understandable by undergraduate students.
description: 12 pages, 2 figures. Accepted for publication in the American Journal of Physics
Distributed Data Management for Large Collaborative Projects: DataLad Ecosystem in Collaborative Research Center 1451
Creators: name: Szczepanik, Michał
name: Heunis, Stephan
name: Mönch, Christian
name: Wagner, Adina Svenja
name: Waite, Alexander
name: Waite, Laura
name: Hanke, Michael
Publisher: name: Forschungzentrum Jülich
Year: 2023

description: From data to Diamonds - Empowering Research with AI and RDM, Aachen, Germany, 14 Nov 2023 - 14 Nov 2023
description: A collaborative research center connects research groups across institutions. Individual and diverse research output needs to become part of the consortium‘s data collection as a whole. This offers unique opportunities, but also challenges. Distributed data management, where projects control key data management decisions (standards, storage, sharing), and the findability, accessibility, interoperability, and reusability of their data is achieved with a common data management software layer (overlay structure) is a possible solution.The poster presents ongoing software developments across the DataLad (datalad.org) ecosystem which are influenced by our involvement as the INF project in CRC1451 (sfb1451.de).
Open research software infrastructure in Neuro-Medicine
Creators: name: Wagner, Adina Svenja
name: Dukart, Jürgen
name: Patil, Kaustubh
Publisher: name: Forschungzentrum Jülich
Year: 2023
Subjects: Open Science
Open Source Software
Research Software
Research Software Engineering
Data Management
Clinical data acquisition
Patient data

description: ZI Mannheim Open Science Symposium, virtual, Germany, 21 Nov 2023; doi:10.5281/ZENODO.10149348
description: A virtual talk given at the ZI Mannheim Open Science Symposium on open source software tools in the INM-7 of the research center Jülich, and plans for a recent collaborative project combing them.   Abstract: The Institute of Neuroscience and Medicine: Brain and Behavior (INM-7) at the research center Jülich combines clinical science with open source software development and open science. This talk will highlight central open source software projects of our institute, and their application in larger projects. As one of its developers, I will introduce the data management software DataLad (www.datalad.org) and some of its applications - from data management in consortia to reproducible and privacy-aware data analysis at scale. In addition, I will outline a recently established collaborative platform for digital medicine in North Rhine Westphalia, the ABCD-JU project. Building on our institute's open source projects for data management, mobile health applications and machine-learning (juaml.github.io/julearn), it aims to establish an integrated, user-friendly, and FAIR infrastructure for digital biomarker collection, storage, and exchange for clinical scientists. Beyond an overview of our tools and projects, this talk aims to spark discussions around synergies and interoperability with projects at the ZI.
Metrizable linear connections in a Lie algebroid
Creators: name: Anastasiei, Mihai
Publisher: name: arXiv
Year: 2010
Subjects: subject: Differential Geometry (math.DG)
subject: FOS: Mathematics
subject: 53C07

description: A linear connection $D$ in a Lie algebroid is said to be metrizable if there exists a Riemannian metric $h$ in the Lie algebroid such that $Dh=0$. Conditions for the linear connection $D$ to be metrizable are investigated.
description: p.10, no figures, Invited paper to celebrate Professor Constantin Udri\c{s}te, on the occasion of his seventies
Investigating the utility of weighting schemes on a 51-member short-range ensemble forecast
Creators: name: McKinney, Reagan
Publisher: name: University of British Columbia
Year: 2024

description: Accurate weather predictions are crucial to the wellbeing of modern society. The Weather Forecast Research Team (WFRT) runs an ensemble of numerical weather prediction models daily (Short Range Ensemble Forecast; SREF 00Z). The ensemble can be combined into an “average” which is usually the best deterministic forecast. In this study, we experiment with ways of improving its skill for southwestern British Columbia. To do this, four different weighting techniques for ensemble averaging are employed using all 51 members of the SREF. These are constructed using 1 year (October 2021-September 2022) of forecasts and observation data pairs from 90 stations in the region, for temperature, wind speed and precipitation. The weights were then applied to a second year of data (October 2022-September 2023) and compared to the current SREF. To investigate the use of a shorter training set on the weights, as suggested by the literature, a sliding window approach was also used with the weights being calculated with the forecast and observation data pairs for the week and month prior to the forecast of interest. We also experimented with varying the number of ensemble members to explore the sensitivity of the SREF to the number of members. Spatially, there were some special cases where the weighted ensembles performed better or poorer than the current SREF. However, all four weighting schemes did not perform statistically significantly compared to the current equally-weighted SREF (pvalue > 0.05). As for the varying number of ensemble members, it was found that the skill of all of the ensembles varied throughout the year and was never consistently in the small or large range for all tested variables. However, we did note that the skill converged for all members greater than 30. This indicated a lower limit of the necessary ensemble members to match the current SREF skill. Future studies should include more data (i.e. longer datasets; climatology) to get a better picture of the state of the SREF and how its members are interacting and performing.
Half-Metallic Silicon Nanowires: Multiple Surface Dangling Bonds and Nonmagnetic Doping
Creators: name: Xu, Zhuo
name: Yan, Qing-Bo
name: Zheng, Qing-Rong
name: Su, Gang
Publisher: name: arXiv
Year: 2009
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: By means of first-principles density functional theory calculations, we find that hydrogen-passivated ultrathin silicon nanowires (SiNWs) along [100] direction with symmetrical multiple surface dangling bonds (SDBs) and boron doping can have a half-metallic ground state with 100% spin polarization, where the half-metallicity is shown quite robust against external electric fields. Under the circumstances with various SDBs, the H-passivated SiNWs can also be ferromagnetic or antiferromagnetic semiconductors. The present study not only offers a possible route to engineer half-metallic SiNWs without containing magnetic atoms but also sheds light on manipulating spin-dependent properties of nanowires through surface passivation.
description: 4 pages, 5 figures
Evolution of the Rate and Mode of Star Formation in Galaxies since z=0.7
Creators: name: Dressler, Alan
name: Oemler,, Augustus
name: Gladders, Michael G.
name: Bai, Lei
name: Rigby, Jane R.
name: Poggianti, Bianca M.
Publisher: name: arXiv
Year: 2009
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We present the star formation rate (SFR) and starburst fraction (SBF) for a sample of field galaxies from the ICBS intermediate-redshift cluster survey. We use [O II] and Spitzer 24 micron fluxes to measure SFRs, and 24 micron fluxes and H-delta absorption to measure of SBFs, for both our sample and a present-epoch field sample from the Sloan Digital Sky Survey (SDSS) and Spitzer Wide-area Infrared Extragalactic (SWIRE) survey. We find a precipitous decline in the SFR since z=1, in agreement with other studies, as well as a corresponding rapid decline in the fraction of galaxies undergoing long-duration moderate-amplitude starbursts. We suggest that the change in both the rate and mode of star formation could result from the strong decrease since z=1 of gas available for star formation.
description: ApJ Letters in press
Improving detection and quantification of major histocompatibility complex (MHC)-presented immunopeptides for vaccine development
Creators: name: Baker, Teesha Crystal
Publisher: name: University of British Columbia
Year: 2024

description: The adaptive immune system relies on antigen presentation governed by major histocompatibility complexes (MHCs), which initiate immune responses upon recognition by T- lymphocytes. Vaccines are designed to create immunological memory by delivering pathogen- derived antigens. Understanding the preferences of MHCs for epitopes is essential for effective vaccine design. Current research lacks insights into why certain antigens, while strongly presented by one MHC allele, may not be recognized at all by others. This thesis investigates the binding preferences for MHC-II-presented peptides, providing a comprehensive understanding of antigen presentation across diverse MHC alleles. If we understand better which epitopes are best recognized and presented by MHCs then we will be able to design more effective vaccines. In the first data chapter, Mild Acid Elution (MAE) is demonstrated as an effective method for isolating MHC-II-presented immunopeptides. This method's potential advantages are highlighted, and the importance of additional separation techniques, such as ion mobility cells and offline reverse-phase chromatography, is emphasized for enhancing peptide identification. Insights into background contamination sources in MAE are explored, paving the way for cleaner data and more accurate immunopeptide identification. The second data chapter addresses the challenges posed by genetic diversity in vaccine development by strategically selecting a panel of 30 cell lines from the 1000 Genomes Project, ensuring global HLA diversity representation. This chapter unveils the intricate nature of antigen identification and binding predictions, emphasizing the unpredictability of immunopeptidomics, and underscoring the need for experimental validation in epitope prediction. The investigation into Salmonella enterica lysate exposure provides valuable insights into potential vaccine candidates and the efficient identification of MHC-presented immunopeptides. This research lays a foundation for leveraging immunopeptidomics in vaccine design and understanding antigen presentation, offering promising avenues for advancements in personalized medicine and vaccine development. In summary, this thesis unveils the potential of MAE for immunopeptide isolation, addresses the complexities of genetic diversity in vaccine development, and emphasizes the importance of experimental identification of vaccine targets.
Star-galaxy separation by far-infrared color-color diagrams for the AKARI FIS All-Sky Survey (Bright Source Catalogue Version beta-1)
Creators: name: Pollo, Agnieszka
name: Rybka, Piotr
name: Takeuchi, Tsutomu T.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: To separate stars and galaxies in the far infrared AKARI All-Sky Survey data, we have selected a sample with the complete color information available in the low extinction regions of the sky and constructed color-color plots for these data. We looked for the method to separate stars and galaxies using the color information. We performed an extensive search for the counterparts of these selected All-Sky Survey sources in the NED and SIMBAD databases. Among 5176 objects, we found 4272 galaxies, 382 other extragalactic objects, 349 Milky Way stars, 50 other Galactic objects, and 101 sources detected before in various wavelengths but of an unknown origin. 22 sources were left unidentified. Then, we checked colors of stars and galaxies in the far-infrared flux-color and color-color plots. In the resulting diagrams, stars form two clearly separated clouds. One of them is easy to be distinguished from galaxies and allows for a simple method of excluding a large part of stars using the far-infrared data. The other smaller branch, overplotting galaxies, consists of stars known to have an infrared excess, like Vega and some fainter stars discovered by IRAS or 2MASS. The color properties of these objects in any case make them very difficult to distinguish from galaxies. We conclude that the FIR color-color diagrams allow for a high-quality star-galaxy separation. With the proposed simple method we can select more that 95 % of galaxies rejecting at least 80 % of stars.
description: 20 pages, 41 figures, "Astronomy & Astrophysics", accepted, to appear in the AKARI special issue
Electron-Hole Asymmetry of Spin Injection and Transport in Single-Layer Graphene
Creators: name: Han, Wei
name: Wang, W. H.
name: Pi, K.
name: McCreary, K. M.
name: Bao, W.
name: Li, Yan
name: Miao, F.
name: Lau, C. N.
name: Kawakami, R. K.
Publisher: name: arXiv
Year: 2009
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Spin-dependent properties of single-layer graphene (SLG) have been studied by non-local spin valve measurements at room temperature. Gate voltage dependence shows that the non-local magnetoresistance (MR) is proportional to the conductivity of the SLG, which is the predicted behavior for transparent ferromagnetic/nonmagnetic contacts. While the electron and hole bands in SLG are symmetric, gate voltage and bias dependence of the non-local MR reveal an electron-hole asymmetry in which the non-local MR is roughly independent of bias for electrons, but varies significantly with bias for holes.
description: To appear in PRL
$Ξ$-nucleus potential and $(K^-,K^+)$ inclusive spectrum at $Ξ^-$ production threshold region
Creators: name: Kohno, Michio
name: Hashimoto, Shintaro
Publisher: name: arXiv
Year: 2009
Subjects: subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: The $(K^-,K^+)$ $Ξ^-$ production inclusive spectrum is reinvestigated in view of the very weak $Ξ$-nucleus potential predicted by microscopic calculations with the SU$_6$ quark-model baryon-baryon interaction. The inclusive spectrum is evaluated by the semiclassical distorted wave (SCDW) method. The explicit comparison of the strength function with that of the Green-function method demonstrates the quantitative reliability of the SCDW approximation. It is presumed that the presently available data at the $Ξ$ production threshold region does not necessarily imply the attractive strength of about 15 MeV for the $Ξ$-nucleus potential in a conventional Woods-Saxon form. Instead, an almost zero potential is preferable.
description: 10 pages including 5 figures
Particle kinematics in a dilute, 3-dimensional, vibration-fluidized granular medium
Creators: name: Wang, Hong-Qiang
name: Feitosa, Klebert
name: Menon, Narayanan
Publisher: name: arXiv
Year: 2009
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: FOS: Physical sciences

description: We report an experimental study of particle kinematics in a 3-dimensional system of inelastic spheres fluidized by intense vibration. The motion of particles in the interior of the medium is tracked by high speed video imaging, yielding a spatially-resolved measurement of the velocity distribution. The distribution is wider than a Gaussian and broadens continuously with increasing volume fraction. The deviations from a Gaussian distribution for this boundary-driven system are different in sign and larger in magnitude than predictions for homogeneously driven systems. We also find correlations between velocity components which grow with increasing volume fraction.
Deterministic fabrication of graphene hexagonal boron nitride moiré superlattices
Creators: name: Kamat, Rupini V.
name: Sharpe, Aaron L.
name: Pendharkar, Mihir
name: Hu, Jenny
name: Tran, Steven J.
name: Zaborski, Gregory
name: Hocking, Marisa
name: Finney, Joe
name: Watanabe, Kenji
name: Taniguchi, Takashi
name: Kastner, Marc A.
name: Mannix, Andrew J.
name: Heinz, Tony
name: Goldhaber-Gordon, David
Publisher: name: arXiv
Year: 2024
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: The electronic properties of moiré heterostructures depend sensitively on the relative orientation between layers of the stack. For example, near-magic-angle twisted bilayer graphene (TBG) commonly shows superconductivity, yet a TBG sample with one of the graphene layers rotationally aligned to a hexagonal Boron Nitride (hBN) cladding layer provided the first experimental observation of orbital ferromagnetism. To create samples with aligned graphene/hBN, researchers often align edges of exfoliated flakes that appear straight in optical micrographs. However, graphene or hBN can cleave along either zig-zag or armchair lattice directions, introducing a 30 degree ambiguity in the relative orientation of two flakes. By characterizing the crystal lattice orientation of exfoliated flakes prior to stacking using Raman and second-harmonic generation for graphene and hBN, respectively, we unambiguously align monolayer graphene to hBN at a near-0 degree, not 30 degree, relative twist angle. We confirm this alignment by torsional force microscopy (TFM) of the graphene/hBN moiré on an open-face stack, and then by cryogenic transport measurements, after full encapsulation with a second, non-aligned hBN layer. This work demonstrates a key step toward systematically exploring the effects of the relative twist angle between dissimilar materials within moiré heterostructures.
description: 40 pages, 15 figures
Pipelined Algorithms to Detect Cheating in Long-Term Grid Computations
Creators: name: Goodrich, Michael T.
Publisher: name: arXiv
Year: 2009
Subjects: subject: Cryptography and Security (cs.CR)
subject: FOS: Computer and information sciences

description: This paper studies pipelined algorithms for protecting distributed grid computations from cheating participants, who wish to be rewarded for tasks they receive but don't perform. We present improved cheater detection algorithms that utilize natural delays that exist in long-term grid computations. In particular, we partition the sequence of grid tasks into two interleaved sequences of task rounds, and we show how to use those rounds to devise the first general-purpose scheme that can catch all cheaters, even when cheaters collude. The main idea of this algorithm might at first seem counter-intuitive--we have the participants check each other's work. A naive implementation of this approach would, of course, be susceptible to collusion attacks, but we show that by, adapting efficient solutions to the parallel processor diagnosis problem, we can tolerate collusions of lazy cheaters, even if the number of such cheaters is a fraction of the total number of participants. We also include a simple economic analysis of cheaters in grid computations and a parameterization of the main deterrent that can be used against them--the probability of being caught.
description: Expanded version with an additional figure; ISSN 0304-3975
Searching Heavily Obscured Post-AGB Stars and Planetary Nebulae I. IRAS Candidates with 2MASS PSC Counterparts
Creators: name: Ramos-Larios, G.
name: Guerrero, M. A.
name: Suarez, O.
name: Miranda, L. F.
name: Gomez, J. F.
Publisher: name: arXiv
Year: 2009
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: The transition from the Asymptotic Giant Branch (AGB) to the planetary nebula (PN) phase is critical in the shaping of PNe. It is suggested that the most asymmetric PNe are the descendant of massive AGB stars. Since these AGB stars are believed to evolve into heavily obscured post-AGB stars and PNe, the compilation of a sample of bona fide obscured post-AGB stars and PNe is important to help understand the formation of asymmetric PNe. We have used 2MASS, Spitzer GLIMPSE, MSX, and IRAS data in search of the near-IR counterparts of a sample of 165 presumably obscured IRAS post-AGB and PN candidates, and DSS red images to identify the optical counterparts among the objects detected in the near-IR. The IR spectral energy distributions (SEDs) in the wavelength range from 1 to 100 microns of the sources with unambiguous near-IR counterparts have been analyzed using appropriate colour-colour diagrams. We have identified the near-IR counterparts of 119 sources out of the 165 IRAS post-AGB and PN candidates in our sample. The improved astrometric coordinates of these sources have allowed us to find optical counterparts for 59 of them, yielding a reduced sample of 60 optically obscured post-AGB star and PN candidates. Among the 119 sources with near-IR counterparts, only 80 have unambiguous identifications in the 2MASS Point Source Catalogue.
description: 13 pages, online material 39 pages (please contact first author for a full version), 5 tables, 8 figures, A&A accepted
On the achievable improvement by the linear minimum mean square error detector
Creators: name: Mohaisen, Manar
name: Chang, KyungHi
Publisher: name: arXiv
Year: 2009
Subjects: subject: Information Theory (cs.IT)
subject: FOS: Computer and information sciences

description: Linear minimum mean square error (MMSE) detector has been shown to alleviate the noise amplification problem, resulting in the conventional zero-forcing (ZF) detector. In this paper, we analyze the performance improvement by the MMSE detector in terms of the condition number of its filtering matrix, and in terms of the post-precessing signal to noise ratio (SNR) improvement. To this end, we derive explicit formulas for the condition numbers of the filtering matrices and the post-processing SNRs. Analytical and simulation results demonstrate that the improvement achieved by the MMSE detector over the ZF detector is not only dependent on the noise variance and the condition number of the channel matrix, but also on how close the smallest singular values are to the noise variance.
description: 5 pages, 6 figures, 1 table, International Symposium on Communications and Information Technologies 2009