cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Extraction of Membrane Components from Neisseria gonorrhoeae Using Catanionic Surfactant Vesicles: A New Approach for the Study of Bacterial Surface Molecules
Creators: name: Stein, Daniel C.
name: Stocker, Lenea H.
name: Powell, Abigail E.
name: Kebede, Salsawi
name: Watts, David
name: Williams, Emma
name: Soto, Nicholas
name: Dhabaria, Avantika
name: Fenselau, Catherine
name: Ganapati, Shweta
name: DeShong, Philip
Publisher: name: MDPI
Year: 2020
Subjects: catanionic surfactant vesicles
antigen
vaccine
Neisseria gonorrhoeae
mass spectral analysis

description: Identification of antigens is important for vaccine production. We tested extraction protocols using cetyltrimethylammonium tosylate (CTAT) and sodium dodecylbenzenesulfonate (SDBS) to formulate surfactant vesicles (SVs) containing components from Neisseria gonorrhoeae. Carbohydrate and protein assays demonstrated that protein and carbohydrates were incorporated into the vesicle leaflet. Depending on the extraction protocol utilized, 100–400 µg of protein/mL of SVs solution was obtained. Gel electrophoresis followed by silver staining demonstrated that SV extracts contained lipooligosaccharide and a subset of bacterial proteins and lipoproteins. Western blotting and mass spectral analysis indicated that the majority of the proteins were derived from the outer membrane. Mass spectrometric and bioinformatics analysis of SVs identified 29 membrane proteins, including porin and opacity-associated protein. Proteins embedded in the SVs leaflet could be degraded by the addition of trypsin or proteinase K. Our data showed that the incorporation of CTAT and SDBS into vesicles eliminated their toxicity as measured by a THP-1 killing assay. Incorporation of gonococcal cell surface components into SVs reduced toxicity as compared to the whole cell extracts, as measured by cytokine induction, while retaining the immunogenicity. This process constitutes a general method for extracting bacterial surface components and identification of antigens that might be included in vaccines.
Phragmén-Lindelöf theorem for infinity harmonic functions
Creators: name: Granlund, Seppo
name: Marola, Niko
Publisher: name: arXiv
Year: 2014
Subjects: subject: Analysis of PDEs (math.AP)
subject: FOS: Mathematics

description: We investigate a version of the Phragmén-Lindelöf theorem for solutions of the equation $Δ_\infty u=0$ in unbounded convex domains. The method of proof is to consider this infinity harmonic equation as the limit of the $p$-harmonic equation when $p$ tends to $\infty$.
Seasonal Ventilation of the Stratosphere: Robust Diagnostics from One-Way Flux Distributions
Creators: name: Orbe, Clara
name: Holzer, Markus
name: Polvani, Lorenzo M.
name: Waugh, Darryn W.
name: Li, Feng
name: Oman, Luke D.
name: Newman, Paul A.
Publisher: name: Columbia University
Year: 2014
Subjects: Stratospheric circulation
Air masses
Atmospheric physics
Tropopause
Atmospheric circulation
Seasons
Atmosphere
Meteorology
Atmosphere, Upper

description: We present an analysis of the seasonally varying ventilation of the stratosphere using one-way flux distributions. Robust transport diagnostics are computed using GEOSCCM subject to fixed present-day climate forcings. From the one-way flux, we determine the mass of the stratosphere that is in transit since entry through the tropical tropopause to its exit back into the troposphere, partitioned according to stratospheric residence time and exit location. The seasonalities of all diagnostics are quantified with respect to the month of year (a) when air enters the stratosphere, (b) when the mass of the stratosphere is partitioned, and (c) when air exits back into the troposphere. We find that the return flux, within 3 months since entry, depends strongly on when entry occurred: (34±10)% more of the air entering the stratosphere in July leaves poleward of 45°N compared to air that enters in January. The month of year when the air mass is partitioned is also found to be important: The stratosphere contains about six times more air of tropical origin during late summer and early fall that will leave poleward of 45° within 6 months since entering the stratosphere compared to during late winter to late spring. When the entire mass of the air that entered the stratosphere at the tropics regardless of its residence time is considered, we find that (51±1)% and (39±2)% will leave poleward of 10° in the Nothern Hemisphere (NH) and Southern Hemisphere (SH), respectively.
Centroid based clustering of high throughput sequencing reads based on n-mer counts
Creators: name: Solovyov, Alexander
name: Lipkin, W. Ian
Publisher: name: Columbia University
Year: 2013
Subjects: subject: Sequence alignment (Bioinformatics)
subject: Bioinformatics
subject: FOS: Computer and information sciences
subject: Bioinformatics--Methodology
subject: Computational biology
subject: Biology

description: Background: Many problems in computational biology require alignment-free sequence comparisons. One of the common tasks involving sequence comparison is sequence clustering. Here we apply methods of alignment-free comparison (in particular, comparison using sequence composition) to the challenge of sequence clustering. Results: We study several centroid based algorithms for clustering sequences based on word counts. Study of their performance shows that using k-means algorithm with or without the data whitening is efficient from the computational point of view. A higher clustering accuracy can be achieved using the soft expectation maximization method, whereby each sequence is attributed to each cluster with a specific probability. We implement an open source tool for alignment-free clustering. It is publicly available from github: https://github.com/luscinius/afcluster. Conclusions: We show the utility of alignment-free sequence clustering for high throughput sequencing analysis despite its limitations. In particular, it allows one to perform assembly with reduced resources and a minimal loss of quality. The major factor affecting performance of alignment-free read clustering is the length of the read.
Compact Object Formation and the Supernova Explosion Engine
Creators: name: Fryer, C. L.
Publisher: name: arXiv
Year: 2013
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: When a massive star ends its life, its core collapses, forming a neutron star or black hole and producing some of the most energetic explosions in the universe. Core-collapse supernovae and long-duration gamma-ray bursts are the violent signatures of compact remnant formation. As such, both fields are intertwined and, coupled with theory, observations of transients can help us better understand compact remnants just as neutron star and black hole observations can constrain the supernova and gamma-ray burst engine. We review these ties in this paper.
description: Invited article for the focus issue on astrophysical black holes in Classical and Quantum Gravity, guest editors: D. Merritt and L. Rezzolla
Rethinking Early-Fusion Strategies for Improved Multispectral Object Detection
Creators: name: Zhang, Xue
name: Cao, Si-Yuan
name: Wang, Fang
name: Zhang, Runmin
name: Wu, Zhe
name: Zhang, Xiaohan
name: Bai, Xiaokai
name: Shen, Hui-Liang
Publisher: name: arXiv
Year: 2024
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: FOS: Computer and information sciences

description: Most recent multispectral object detectors employ a two-branch structure to extract features from RGB and thermal images. While the two-branch structure achieves better performance than a single-branch structure, it overlooks inference efficiency. This conflict is increasingly aggressive, as recent works solely pursue higher performance rather than both performance and efficiency. In this paper, we address this issue by improving the performance of efficient single-branch structures. We revisit the reasons causing the performance gap between these structures. For the first time, we reveal the information interference problem in the naive early-fusion strategy adopted by previous single-branch structures. Besides, we find that the domain gap between multispectral images, and weak feature representation of the single-branch structure are also key obstacles for performance. Focusing on these three problems, we propose corresponding solutions, including a novel shape-priority early-fusion strategy, a weakly supervised learning method, and a core knowledge distillation technique. Experiments demonstrate that single-branch networks equipped with these three contributions achieve significant performance enhancements while retaining high efficiency. Our code will be available at \url{https://github.com/XueZ-phd/Efficient-RGB-T-Early-Fusion-Detection}.
description: This paper has been accepted by IEEE T-IV journal. Please jump to External DOI to view the official version
Superconducting energy gap versus pseudogap in hole-doped cuprates as revealed by infrared spectroscopy
Creators: name: Dong, T.
name: Zhou, F.
name: Wang, N. L.
Publisher: name: arXiv
Year: 2013
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We present in-plane infrared reflectance measurement on two superconducting cuprates with relatively low T$_c$: a nearly optimally-doped Bi$_2$Sr$_{1.6}$La$_{0.4}$CuO$_{6+δ}$ with T$_c$=33 K and an underdoped La$_{1.89}$Sr$_{0.11}$CuO$_4$ with T$_c$=30 K. The measurement clearly reveals that the superconducting energy gap is distinct from the pseudogap. They have different energy scales and appear at different temperatures. The results suggest that the pseudogap is not a precursor to the superconducting state. The data also challenge the longstanding viewpoint that the superconductivity within the ab-plane is in the clean limit and the superconducting pairing energy gap could not be detected by in-plane infrared spectroscopy.
description: 5 pages, 4 figures
NOAA Satellite Soil Moisture Operational Product System (SMOPS) Version 3.0 Generates Higher Accuracy Blended Satellite Soil Moisture
Creators: name: Yin, Jifu
name: Zhan, Xiwu
name: Liu, Jicheng
Publisher: name: MDPI
Year: 2020
Subjects: satellite soil moisture
SMOPS
remote sensing
near real time

description: Soil moisture plays a vital role for the understanding of hydrological, meteorological, and climatological land surface processes. To meet the need of real time global soil moisture datasets, a Soil Moisture Operational Product System (SMOPS) has been developed at National Oceanic and Atmospheric Administration to produce a one-stop shop for soil moisture observations from all available satellite sensors. What makes the SMOPS unique is its near real time global blended soil moisture product. Since the first version SMOPS publicly released in 2010, the SMOPS has been updated twice based on the users’ feedbacks through improving retrieval algorithms and including observations from new satellite sensors. The version 3.0 SMOPS has been operationally released since 2017. Significant differences in climatological averages lead to remarkable distinctions in data quality between the newest and the older versions of SMOPS blended soil moisture products. This study reveals that the SMOPS version 3.0 has overwhelming advantages of reduced data uncertainties and increased correlations with respect to the quality controlled in situ measurements. The new version SMOPS also presents more robust agreements with the European Space Agency’s Climate Change Initiative (ESA_CCI) soil moisture datasets. With the higher accuracy, the blended data product from the new version SMOPS is expected to benefit the hydrological, meteorological, and climatological researches, as well as numerical weather, climate, and water prediction operations.
Many-particle quantum graphs and Bose-Einstein condensation
Creators: name: Bolte, Jens
name: Kerner, Joachim
Publisher: name: arXiv
Year: 2013
Subjects: subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: In this paper we propose quantum graphs as one-dimensional models with a complex topology to study Bose-Einstein condensation and phase transitions in a rigorous way. We fist investigate non-interacting many-particle systems on quantum graphs and provide a complete classification of systems that exhibit Bose-Einstein condensation. We then consider models of interacting particles that can be regarded as a generalisation of the well-known Tonks-Girardeau gas. Here our principal result is that no phase transitions occur in bosonic systems with repulsive hardcore interactions, indicating an absence of Bose-Einstein condensation.
Proglacial lake sediment records reveal Holocene climate changes in the Venezuelan Andes
Creators: name: Stansell, Nathan D.
name: Polissar, Pratigya Jeremy
name: Abbott, Mark B.
name: Bezadad, Maximiliano
name: Steinmane, Byron A.
name: Braunf, Carsten
Publisher: name: Columbia University
Year: 2014
Subjects: subject: Paleoclimatology
subject: Glacial landforms
subject: Sediments (Geology)
subject: Geochemistry
subject: FOS: Earth and related environmental sciences
subject: Glacial epoch
subject: Climatic changes
subject: Holocene Geologic Period
subject: Geology, Stratigraphic

description: Lake sediment records from the Cordillera de Mérida in the northern Venezuelan Andes document the history of local glacial variability and climate changes during the Holocene (∼12 ka to the present). The valleys that contain these lakes have similar bedrock compositions and hypsometries, but have different headwall elevations and aspects, which makes them useful for investigating the magnitude of past glaciations. There was widespread glacial retreat in the Venezuelan Andes during the early Holocene, after which most watersheds remained ice free, and thus far only valleys with headwalls higher than ∼4400 m asl contain evidence of glaciation during the last ∼10 ka. There was a pronounced shift in sediment composition for the Montos (headwall: ∼4750 m asl) and Los Anteojos (headwall: ∼4400 m asl) records during the middle Holocene from ∼8.0 to 7.7 ka when conditions appear to have become ice free and drier. There is tentative evidence that the glacier in the Mucubají valley (headwall: ∼4609 m asl) advanced from ∼8.1 to 6.6 ka and then retreated during the latter stages of the middle Holocene. Clastic sediment accumulation in other nearby lake basins was either low or decreased throughout most of the middle Holocene as watersheds stabilized under warmer and/or drier conditions. In the Montos record, there was another major shift in sediment composition that occurred from ∼6.5 to 5.7 ka, similar to other regional records that suggest conditions were drier during this period. Overall, the late Holocene was a period of warmer and wetter conditions with ice extent at a minimum in the northern tropical Andes. There were also punctuated decadal to multi-centennial periods of higher clastic sediment accumulation during the last ∼4 ka, likely in response to periods of cooling and/or local precipitation changes. In watersheds with headwalls above 4600 m asl, there is evidence of glacial advances during the Little Ice Age (∼0.6–0.1 ka). The pattern of glacial variability is generally similar in both the northern and southern tropics during the Little Ice Age, suggesting that ice margins in both regions were responding to colder and wetter conditions during the latest Holocene. The observed pattern of Holocene climate variability in the Venezuelan Andes cannot be explained by insolation forcing alone, and tropical ocean influences were likely associated with the observed glacial and lake level changes.
Early adaptive schemas, emotional regulation and cognitive flexibility in eating disorders: Exploring predictors of eating disorder symptoms using hierarchical multiple regression
Creators: name: Mitchell, Jules
name: Huckstepp, Tyrone
name: Allen, Andrew
name: Hermens, Daniel
name: Lagopoulos, Jim
Publisher: name: Open Science Framework
Year: 2022
Subjects: subject: Quantitative Psychology
subject: Social and Behavioral Sciences
subject: Psychology
subject: FOS: Psychology
subject: cognitive flexibility
subject: early adaptive schemas
subject: eating disorders
subject: emotional regulation

description: A dataset of 1576 online self-reported survey responses; 1420 with complete 156 with incomplete, was collected by collaborator Tyrone Huckstepp as part of a Master's Thesis. Sub-groups of this data have previous been utilised by Huckstepp et al. (unpublished manuscript) and Maher et al. (2022; Clinical Psychology and Psychotherapy) in a factorial analysis and heirarchical multiple regression, respectively. The current study aims to use the entire dataset to investigate how early adaptive schemas, cognitive flexibility, and emotional regulation predict eating disorder symptoms, and whether this differs across diagnostic subtypes is critical to optimising treatment, particularly cognitive-behavioural and schema focused therapies. At the time of registration, only cleaning of the complete dataset has been completed Huckstepp, with no analyses performed. A hierarchical multiple regression (HMR) analysis will be used to evaluate the variability each predictor accounts for in eating disorder symptoms (measured by the Eating Disorder Examination Questionnaire 6.0 (EDE-Q 6.0) in individuals self-reporting an eating disorder diagnosis. Missing data analysis will be conducted to evaluate the missing nature of the data prior to descriptive and inferential analysis. For the HMR, model one will include covariates (e.g. age, sex, body-mass-index), model two will include cognitive flexibility (i.e. Cognitive Flexibility Inventory (CFI); alternate and control) and emotional regulation (i.e. Emotional Regulation Questionnaire (ERQ); cognitive reappraisal and expressive submissive) subscales, and model three will include the nine-factor structure (emotional fulfilment and stable attachment, success, empathic consideration, optimism, emotional openness, self-compassion and realistic expectations, developed self, social belonging, healthy self-control) of the Young Positive Schema questionnaire. Results will be tabulated and discussed to determine the variance in eating disorder symptoms accounted for by each model, and the individual significant predictors across eating disorder diagnoses.
R2 vertices for the effective ggH theory
Creators: name: Page, Ben
name: Pittau, Roberto
Publisher: name: arXiv
Year: 2013
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We list all possible R2 Feynman rules needed in NLO computations involving couplings of Higgs and gluons mediated by an infinitely heavy top loop. They provide the rational contribution generated by the (d-4)-dimensional part of the amplitude, paving the way for four-dimensional automatic NLO methods in Higgs phenomenology.
description: 7 pages, 1 figure
On the surface impact of Arctic stratospheric ozone extremes
Creators: name: Calvo, N.
name: Polvani, Lorenzo M.
name: Solomon, S.
Publisher: name: Columbia University
Year: 2015
Subjects: Ozone layer
Atmospheric chemistry
Atmospheric chemistry--Environmental aspects
Fluid dynamics
Ozone layer depletion
Atmospheric ozone
Stratosphere
Atmosphere
Meteorology
Climatic changes

description: A comprehensive stratosphere-resolving atmospheric model, with interactive stratospheric ozone chemistry, coupled to ocean, sea ice and land components is used to explore the tropospheric and surface impacts of large springtime ozone anomalies in the Arctic stratosphere. Coupling between the Antarctic ozone hole and Southern Hemisphere climate has been identified in numerous studies, but connections of Arctic ozone loss to surface climate have been more difficult to elucidate. Analyzing an ensemble of historical integrations with all known natural and anthropogenic forcings specified over the period 1955–2005, we find that extremely low stratospheric ozone changes are able to produce large and robust anomalies in tropospheric wind, temperature and precipitation in April and May over large portions of the Northern Hemisphere (most notably over the North Atlantic and Eurasia). Further, these ozone-induced surface anomalies are obtained only in the last two decades of the 20th century, when high concentrations of ozone depleting substances generate sufficiently strong stratospheric temperature anomalies to impact the surface climate. Our findings suggest that coupling between chemistry and dynamics is essential for a complete representation of surface climate variability and climate change not only in Antarctica but also in the Arctic.
Some Remarks on Kite Pseudo Effect Algebras
Creators: name: Dvurečenskij, Anatolij
name: Holland, W. Charles
Publisher: name: arXiv
Year: 2013
Subjects: subject: Rings and Algebras (math.RA)
subject: FOS: Mathematics
subject: 81P10, 03G12

description: Recently a new family of pseudo effect algebras, called kite pseudo effect algebras, was introduced. Such an algebra starts with a po-group $G$, a set $I$ and with two bijections $λ,ρ:I \to I.$ Using a clever construction on the ordinal sum of $(G^+)^I$ and $(G^-)^I,$ we can define a pseudo effect algebra which can be non-commutative even if $G$ is an Abelian po-group. In the paper we give a characterization of subdirect product of subdirectly irreducible kite pseudo effect algebras, and we show that every kite pseudo effect algebra is an interval in a unital po-loop.
description: arXiv admin note: text overlap with arXiv:1306.0304
Using 164 Million Google Street View Images to Derive Built Environment Predictors of COVID-19 Cases
Creators: name: Nguyen, Quynh C.
name: Huang, Yuru
name: Kumar, Abhinav
name: Duan, Haoshu
name: Keralis, Jessica M.
name: Dwivedi, Pallavi
name: Meng, Hsien-Wen
name: Brunisholz, Kimberly D.
name: Jay, Jonathan
name: Javanmardi, Mehran
name: Tasdizen, Tolga
Publisher: name: MDPI
Year: 2020
Subjects: COVID-19
built environment
big data
GIS
computer vision
machine learning

description: The spread of COVID-19 is not evenly distributed. Neighborhood environments may structure risks and resources that produce COVID-19 disparities. Neighborhood built environments that allow greater flow of people into an area or impede social distancing practices may increase residents’ risk for contracting the virus. We leveraged Google Street View (GSV) images and computer vision to detect built environment features (presence of a crosswalk, non-single family home, single-lane roads, dilapidated building and visible wires). We utilized Poisson regression models to determine associations of built environment characteristics with COVID-19 cases. Indicators of mixed land use (non-single family home), walkability (sidewalks), and physical disorder (dilapidated buildings and visible wires) were connected with higher COVID-19 cases. Indicators of lower urban development (single lane roads and green streets) were connected with fewer COVID-19 cases. Percent black and percent with less than a high school education were associated with more COVID-19 cases. Our findings suggest that built environment characteristics can help characterize community-level COVID-19 risk. Sociodemographic disparities also highlight differential COVID-19 risk across groups of people. Computer vision and big data image sources make national studies of built environment effects on COVID-19 risk possible, to inform local area decision-making.
Kesa : the elegance of Japanese monks' robes
Creators: name: Swart, Paula
name: Till, Barry, 1951-
Publisher: name: University of Victoria Libraries
Year: 2020
Subjects: subject: Exhibition catalogs
valueUri: http://id.worldcat.org/fast/1424028
subject: Cloaks
valueUri: http://id.worldcat.org/fast/864497
subject: Buddhist monks--Clothing
valueUri: http://id.worldcat.org/fast/840234
subject: Buddhism
valueUri: http://id.worldcat.org/fast/840028
subject: Buddhist monks
valueUri: http://id.worldcat.org/fast/840233
subject: Exhibitions
valueUri: http://id.worldcat.org/fast/918097
subject: Monasticism and religious orders--Habit
valueUri: http://id.worldcat.org/fast/1025140
subject: Art Gallery of Greater Victoria
valueUri: http://id.worldcat.org/fast/510434
subject: Buddhist monasticism and religious orders
valueUri: http://id.worldcat.org/fast/1727614
subject: Art
valueUri: http://id.worldcat.org/fast/815177

description: Catalogue of an exhibition featuring Japanese examples of Buddhist monk's robes held at the Art Gallery of Greater Victoria, April 5-May 26, 1996, and the Seattle Art Museum, July-September 1996 connected to a visit from the Dalai Lama. Includes bibliographical references (page 64). Designed and printed by Morriss Printing Company Ltd. Victoria, British Columbia.
Constraints on the salinity–oxygen isotope relationship in the central tropical Pacific Ocean
Creators: name: Conroy, Jessica L.
name: Cobb, Kim M.
name: Lynch-Stieglitz, Jean
name: Polissar, Pratigya Jeremy
Publisher: name: Columbia University
Year: 2014
Subjects: Salinity
Oxygen--Isotopes
Seawater
Chemical oceanography
Chemistry
Paleoclimatology

description: Uncertainties surround the relationship between salinity and the stable isotopic composition of seawater, largely due to a dearth of modern seawater isotope data. Here we report 191 new, paired measurements of salinity and seawater oxygen isotopes (δ¹⁸O_sw) taken from the central tropical Pacific in May 2012, from the surface to 4600 m depth. We observe significant correlations between δ¹⁸O_sw and salinity across the study region, with slopes ranging from 0.23 to 0.31‰/psu for the mixed layer, and 0.35–0.42‰/psu for waters between the mixed layer and 500 m depth. When considering δ¹⁸O_sw–salinity across averages of individual water masses in the region, slopes range from 0.21 to 0.40‰/psu, albeit with appreciable scatter. Surface salinity and δ¹⁸O_sw data corresponding to the North Equatorial Countercurrent are significantly higher than previously observed, which we attribute to a weak westerly current and dry conditions in the region during the May 2012 cruise. Subsurface (80–500 m) salinity values from 2012 are significantly lower than corresponding values from pre-existing regional data, highlighting a different latitudinal sampling distribution, while subsurface δ¹⁸O_sw is not significantly different. Thus, in May 2012, δ¹⁸O_sw in this region could not be used to distinguish between subsurface water masses of different salinities. Unlike other regions where the surface ‘freshwater endmember’ is close to the δ¹⁸O value of regional precipitation, the freshwater endmember implied by our dataset (− 10.38‰) is consistent with a strong evaporative influence. Paired δ¹⁸O–δD values of precipitation and surface seawaters have similar slopes (5.0, 5.1), and relatively low intercepts (1.4, 0.8) indicating isotopic variability in both reservoirs is also partly controlled by evaporation.
Flavor physics with $Λ_b$ baryons
Creators: name: Meinel, Stefan
Publisher: name: arXiv
Year: 2014
Subjects: subject: High Energy Physics - Lattice (hep-lat)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: At the LHC, bottom baryons are being produced in unprecedented quantities, which opens up a new field for flavor physics. For example, the decay $Λ_b \to p μ^- \barν$ can be used to obtain a novel determination of the CKM matrix element $|V_{ub}|$, and the decay $Λ_b \to Λμ^+ μ^-$ probes the weak interactions at the loop level. The first lattice calculations of the relevant $Λ_b \to p$ and $Λ_b \to Λ$ form factors have recently been performed using domain-wall light quarks and static $b$ quarks. To further reduce the theoretical uncertainty, one has to go beyond the static approximation. Here I present new calculations of $Λ_b \to p$, $Λ_b \to Λ$, and $Λ_b \to Λ_c$ form factors using a relativistic heavy-quark action.
description: 15 pages, 12 figures, plenary talk presented at the 31st International Symposium on Lattice Field Theory (Lattice 2013), 29 July - 3 August 2013, Mainz, Germany
Comparison of polarization switching in ferroelectric TGS and relaxor SBN crystals
Creators: name: Matyjasek, K.
name: Orłowski, M.
Publisher: name: arXiv
Year: 2013
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: The comparative experimental analysis of polarization reversal kinetics in conventional homogeneous triglycine sulfate ((NH_{2}CH_{2}COOH)_{3} \cdot H_{2}SO_{4}; TGS) and relaxor strontium barium niobate (Sr_{0.61}Ba_{0.39}Nb_{2}O_{6}; SBN) crystals have been performed in a broad range of measurement conditions. The experimental data have been collected from microscopic observation of the domain structure, switching current and D-E hysteresis loop registration. The hysteresis loop and dielectric spectra have a strong link to the configuration of ferroelectric microdomains. The domain structure dynamics was examined by the nematic liquid crystal (NLC) method.
description: 6 pages, 6 figures
Slowly converging Yamabe flows
Creators: name: Carlotto, Alessandro
name: Chodosh, Otis
name: Rubinstein, Yanir A.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Analysis of PDEs (math.AP)
subject: Differential Geometry (math.DG)
subject: FOS: Mathematics

description: We characterize the rate of convergence of a converging volume-normalized Yamabe flow in terms of Morse theoretic properties of the limiting metric. If the limiting metric is an integrable critical point for the Yamabe functional (for example, this holds when the critical point is non-degenerate), then we show that the flow converges exponentially fast. In general, we make use of a suitable Lojasiewicz-Simon inequality to prove that the slowest the flow will converge is polynomially. When the limit metric satisfies an Adams-Simon type condition we prove that there exist flows converging to it exactly at a polynomial rate. We conclude by constructing explicit examples to show that this does occur; these seem to be the first examples of a slowly converging solution to a geometric flow.
description: Some corrections. To appear in Geometry & Topology
Gravitational Production of Completely Dark Photons with Nonminimal Couplings to Gravity
Creators: name: Capanelli, Christian
name: Jenks, Leah
name: Kolb, Edward W.
name: McDonough, Evan
Publisher: name: arXiv
Year: 2024
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Dark photons are a theorized massive spin-1 particle which can be produced via various mechanisms, including cosmological gravitational particle production (GPP) in the early universe. In this work, we extend previous results for GPP of dark photons to include nonminimal couplings to gravity. We find that nonminimal couplings can induce a ghost instability or lead to runaway particle production at high momentum and discuss the constraints on the parameter space such that the theory is free of instabilities. Within the instability-free regime we numerically calculate the particle production and find that the inclusion of nonminimal couplings can lead to an enhancement of the particle number. As a result, GPP of nonminimally coupled dark photons can open the parameter space for production of a cosmological relevant relic density (constituting all or part of the dark matter) as compared to the minimally-coupled theory. These results are independent of the choice of inflation model, which we demonstrate by repeating the analysis for a class of rapid-turn multi-field inflation models.
description: 26 pages, 14 figures, references added
Evaluation of GEOS-Simulated L-Band Microwave Brightness Temperature Using Aquarius Observations over Non-Frozen Land across North America
Creators: name: Park, Jongmin
name: Forman, Barton A.
name: Reichle, Rolf H.
name: De Lannoy, Gabrielle
name: Tarik, Saad B.
Publisher: name: MDPI
Year: 2020
Subjects: L-band radiometry
radiative transfer model
soil moisture

description: L-band brightness temperature (𝑇𝑏) is one of the key remotely-sensed variables that provides information regarding surface soil moisture conditions. In order to harness the information in 𝑇𝑏 observations, a radiative transfer model (RTM) is investigated for eventual inclusion into a data assimilation framework. In this study, 𝑇𝑏 estimates from the RTM implemented in the NASA Goddard Earth Observing System (GEOS) were evaluated against the nearly four-year record of daily 𝑇𝑏 observations collected by L-band radiometers onboard the Aquarius satellite. Statistics between the modeled and observed 𝑇𝑏 were computed over North America as a function of soil hydraulic properties and vegetation types. Overall, statistics showed good agreement between the modeled and observed 𝑇𝑏 with a relatively low, domain-average bias (0.79 K (ascending) and −2.79 K (descending)), root mean squared error (11.0 K (ascending) and 11.7 K (descending)), and unbiased root mean squared error (8.14 K (ascending) and 8.28 K (descending)). In terms of soil hydraulic parameters, large porosity and large wilting point both lead to high uncertainty in modeled 𝑇𝑏 due to the large variability in dielectric constant and surface roughness used by the RTM. The performance of the RTM as a function of vegetation type suggests better agreement in regions with broadleaf deciduous and needleleaf forests while grassland regions exhibited the worst accuracy amongst the five different vegetation types.
Isotope Spectroscopy
Creators: name: Caffau, E.
name: Steffen, M.
name: Bonifacio, P.
name: Ludwig, H. -G.
name: Monaco, L.
name: Curto, G. Lo
name: Kamp, I.
Publisher: name: arXiv
Year: 2013
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: The measurement of isotopic ratios provides a privileged insight both into nucleosynthesis and into the mechanisms operating in stellar envelopes, such as gravitational settling. In this article, we give a few examples of how isotopic ratios can be determined from high-resolution, high-quality stellar spectra. We consider examples of the lightest elements, H and He, for which the isotopic shifts are very large and easily measurable, and examples of heavier elements for which the determination of isotopic ratios is more difficult. The presence of 6Li in the stellar atmospheres causes a subtle extra depression in the red wing of the 7Li 670.7 nm doublet which can only be detected in spectra of the highest quality. But even with the best spectra, the derived $^6$Li abundance can only be as good as the synthetic spectra used for their interpretation. It is now known that 3D non-LTE modelling of the lithium spectral line profiles is necessary to account properly for the intrinsic line asymmetry, which is produced by convective flows in the atmospheres of cool stars, and can mimic the presence of 6Li. We also discuss briefly the case of the carbon isotopic ratio in metal-poor stars, and provide a new determination of the nickel isotopic ratios in the solar atmosphere.
description: AIP Thinkshop 10 "High resolution optical spectroscopy", invited talk, AN in press
Integration of Dirac’s Efforts to Construct a Quantum Mechanics Which is Lorentz-Covariant
Creators: name: Kim, Young S.
name: Noz, Marilyn E.
Publisher: name: MDPI
Year: 2020
Subjects: Dirac's relativistic quantum mechanics
Lorentz-covariant harmonic oscillators
special relativity from the Heisenberg brackets

description: The lifelong efforts of Paul A. M. Dirac were to construct localized quantum systems in the Lorentz covariant world. In 1927, he noted that the time-energy uncertainty should be included in the Lorentz-covariant picture. In 1945, he attempted to construct a representation of the Lorentz group using a normalizable Gaussian function localized both in the space and time variables. In 1949, he introduced his instant form to exclude time-like oscillations. He also introduced the light-cone coordinate system for Lorentz boosts. Also in 1949, he stated the Lie algebra of the inhomogeneous Lorentz group can serve as the uncertainty relations in the Lorentz-covariant world. It is possible to integrate these three papers to produce the harmonic oscillator wave function which can be Lorentz-transformed. In addition, Dirac, in 1963, considered two coupled oscillators to derive the Lie algebra for the generators of the 𝑂(3,2) de Sitter group, which has ten generators. It is proven possible to contract this group to the inhomogeneous Lorentz group with ten generators, which constitute the fundamental symmetry of quantum mechanics in Einstein’s Lorentz-covariant world.
Electrophysical properties of PMN-PT-PS-PFN:Li ceramics
Creators: name: Skulski, R.
name: Bochenek, D.
name: Niemiec, P.
name: Wawrzała, P.
name: Suchanicz, J.
Publisher: name: arXiv
Year: 2013
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: We present the technology of obtaining and the electrophysical properties of a multicomponent material 0.61PMN-0.20PT-0.09PS-0.1PFN:Li (PMN-PT-PS-PFN:Li). The addition of PFN into PMN-PT decreases the temperature of final sintering which is very important during technological process (addition of Li decreases electric conductivity of PFN). Addition of PS i.e., PbSnO_3 (which is unstable in ceramic form) permits to shift the temperature of the maximum of dielectric permittivity. One-step method of obtaining ceramic samples from oxides and carbonates has been used. XRD, microstructure, scanning calorimetry measurements and the main dielectric, ferroelectric and electromechanical properties have been investigated for the obtained samples.
description: 6 pages, 7 figures
DSP and Optimization for System-Level and Component-Level Improvements in Coherent Optical Communications
Creators: name: Babaee, Ramin
Publisher: name: Université d'Ottawa / University of Ottawa
Year: 2023
Subjects: DSP
DAC
Coherent optical transmission
Precoding
Distortion
Constellation shaping

description: Fiber-optic communications are the backbone of the internet and are responsible for carrying an enormous amount of traffic each day. This thesis presents system-level and component-level innovations to unlock the full potential of fiber-optic communications and address existing challenges, including limited tracking performance, static and dynamic distortions in digital-to-analog converter (DAC), and the issue of joint precoding and constellation shaping. Equalization is an essential part of optical communications systems to mitigate fiber distortions. State-of-polarization (SOP) is a stochastic property of fiber and fast changes can cause the receiver to lose track. In the first part of this thesis, several equalization methods are proposed to enhance the tracking performance of the coherent optical receivers. DAC and analog-to-digital converter (ADC) are two prime enablers of high-speed optical transmission. However, their performance is largely limited by the distortions caused by component mismatches. In this thesis, I study three sources of DAC distortions, fall/rise asymmetry response, current amplitude mismatches, and random timing errors among DAC switches. In the second part of this thesis, a novel optimization framework is introduced for deriving optimized DAC structures that achieve significantly lower distortion and can be easily adopted in the industry. Various digital signal processing (DSP) algorithms are also proposed for further improvement of DAC performance. The third part of this thesis tackles the issue of combined precoding and constellation shaping at the transmitter. A shaping algorithm is introduced based on a stationary Markov process where the transition probability distribution of symbols is optimized. The proposed scheme can achieve shaping gain in combination with the pre-equalization of channel response at the transmitter.
La Trobe eBureau author kit
Creators: name: eBureau, La Trobe
name: Chang, Steven
name: Kainey, Sebastian
Publisher: name: La Trobe
Year: 2022
Subjects: subject: 80706 Librarianship
subject: FOS: Media and communications
subject: Library and Information Studies
subject: 80799 Library and Information Studies not elsewhere classified

description: Author kit for La Trobe academics aiming to publish open educational resources with the La Trobe eBureau.
Includes:* expression of interest form* author proposal template* author copyright agreement* overview of eBureau publishing process
The response midlatitude jets to increased CO2: Distinguishing the roles of sea surface temperature and direct radiative forcing
Creators: name: Grise, Kevin M.
name: Polvani, Lorenzo M.
Publisher: name: Columbia University
Year: 2014
Subjects: Ocean temperature
Tropospheric circulation
Atmospheric circulation
Atmospheric chemistry
Atmospheric carbon dioxide
Atmosphere
Meteorology
Climatic changes

description: In Coupled Model Intercomparison Project Phase 5 (CMIP5) models, the zonal-mean tropospheric circulation shifts robustly poleward in the Southern Hemisphere extratropics in response to increased atmospheric CO₂ concentrations. However, in the Northern Hemisphere (NH) extratropics, the circulation response to CO₂ is largely absent in the zonal mean and is instead characterized by complex regional anomalies. This study decomposes the atmospheric circulation response to CO₂ forcing in CMIP5 models into two components: a direct component due to CO₂ radiative forcing and an indirect component associated with sea surface temperature (SST)-mediated changes. The direct radiative forcing of CO₂ drives a weak poleward jet shift in both hemispheres, whereas the indirect (SST) component of the CO₂ forcing dominates the total response and drives a zonally asymmetric response in the NH. Hence, understanding the SST-mediated component of atmospheric CO₂ forcing appears crucial to unlocking the mechanisms that contribute to forced extratropical circulation changes.
Distinguishing the impacts of ozone-depleting substances and well-mixed greenhouse gases on Arctic stratospheric ozone and temperature trends
Creators: name: Reider, Harald
name: Polvani, Lorenzo M.
name: Solomon, Susan
Publisher: name: Columbia University
Year: 2014
Subjects: Stratosphere
Ozone layer depletion
Atmospheric temperature
Ozone-depleting substances
Greenhouse gases
Atmospheric ozone
Atmosphere
Climatic changes
Atmospheric chemistry

description: Whether stratospheric cooling due to increases in well-mixed greenhouse gases (WMGHG) could increase the depletion of Arctic stratospheric ozone has been the subject of scientific and public attention for decades. Here we provide evidence that changes in the concentrations of ozone-depleting substances (ODS), not WMGHG, have been the primary driver of observed Arctic lower stratospheric trends in both ozone and temperature. We do so by analyzing polar cap ozone and temperature trends in reanalysis data: these clearly suggest that both trends are mainly driven by ODS in the lower stratosphere. This observation-based finding is supported by results from a stratosphere-resolving chemistry-climate model driven with time-varying ODS and WMGHG, specified in isolation and in combination. Taken together, these results provide strong evidence that ODS are the main driver of changes in the Arctic lower stratospheric temperatures and ozone, whereas WMGHG are the primary driver of changes in the upper stratosphere.
Quadrupole coupling of circular Rydberg qubits to inner shell excitations
Creators: name: Wirth, Moritz
name: Hölzl, Christian
name: Götzelmann, Aaron
name: Pultinevicius, Einius
name: Meinert, Florian
Publisher: name: arXiv
Year: 2024
Subjects: subject: Atomic Physics (physics.atom-ph)
subject: Quantum Gases (cond-mat.quant-gas)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Divalent atoms provide excellent means for advancing control in Rydberg atom-based quantum simulation and computing, due to the second optically active valence electron available. Particularly promising in this context are circular Rydberg atoms, for which long-lived ionic core excitations can be exploited without suffering from detrimental autoionization. Here, we report the implementation of electric quadrupole coupling between the metastable 4D$_{3/2}$ level and a very high-$n$ ($n=79$) circular Rydberg qubit, realized in doubly excited $^{88}$Sr atoms prepared from an optical tweezer array. We measure the kHz-scale differential level shift on the circular Rydberg qubit via beat-node Ramsey interferometry comprising spin echo. Observing this coupling requires coherent interrogation of the Rydberg states for more than one hundred microseconds, which is assisted by tweezer trapping and circular state lifetime enhancement in a black-body radiation suppressing capacitor. Further, we find no noticeable loss of qubit coherence under continuous photon scattering on the ion core, paving the way for laser cooling and imaging of Rydberg atoms. Our results demonstrate access to weak electron-electron interactions in Rydberg atoms and expand the quantum simulation toolbox for optical control of highly excited circular state qubits via ionic core manipulation.
description: 8 pages, 5 figures
Generating Entangled Spin States for Quantum Metrology by Single-Photon Detection
Creators: name: McConnell, Robert
name: Zhang, Hao
name: Ćuk, Senka
name: Hu, Jiazhong
name: Schleier-Smith, Monika H.
name: Vuletić, Vladan
Publisher: name: arXiv
Year: 2013
Subjects: subject: Atomic Physics (physics.atom-ph)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We propose and analyze a probabilistic but heralded scheme to generate pure, entangled, non-Gaussian states of collective spin in large atomic ensembles by means of single-photon detection. One photon announces the preparation of a Dicke state, while two or more photons announce Schrödinger cat states. The method produces pure states even for finite photon detection efficiency and weak atom-photon coupling. The entanglement generation can be made quasi-deterministic by means of repeated trial and feedback, enabling metrology beyond the standard quantum limit.
description: 5 pages, 3 figures
Contrasting short and long term projections of the hydrological cycle in the Southern extratropics
Creators: name: Wu, Yutian
name: Polvani, Lorenzo M.
Publisher: name: Columbia University
Year: 2015
Subjects: Atmospheric chemistry--Environmental aspects
Stratospheric chemistry
Climatic changes
Ozone-depleting substances
Hydrologic cycle
Precipitation (Meteorology)
Atmosphere
Meteorology

description: Analysis of model output from phase 5 of the Coupled Model Intercomparison Project (CMIP5) reveals that, in the zonal mean, the near-term projections of summertime changes of precipitation in the Southern Hemisphere (SH) subtropics are very widely scattered among the models. As a consequence, over the next 50 years, the CMIP5 multimodel mean projects no statistically significant trends in the SH subtropics in summer. This appears to be at odds with the widely reported, and robust, poleward expansion of the subtropical dry zones by the end of the twenty-first century. This discrepancy between the shorter- and longer-term projections in SH summer, as shown here, rests in the recovery of the ozone hole in the coming decades, as a consequence of the Montreal Protocol. This is explicitly demonstrated by analyzing model experiments with the Whole Atmosphere Community Climate Model, version 4 (WACCM4), a high-top model with interactive stratospheric chemistry, and coupled to land, ocean, and sea ice components. Contrasting WACCM4 integrations of the representative concentration pathway 4.5 with and without trends in surface concentrations of ozone-depleting substances allows for demonstrating that stratospheric ozone recovery will largely offset the induced “wet gets wetter and dry gets drier” projections and the accompanying poleward expansion of the subtropical dry zone in the SH. The lack of near-term statistically significant zonal-mean changes in the SH hydrological cycle during summer is of obvious practical importance for many parts of the world, and it might also have implications for the Southern Ocean and the Antarctic continent.