cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Polylidar -- Polygons from Triangular Meshes
Creators: name: Castagno, Jeremy
name: Atkins, Ella
Publisher: name: arXiv
Year: 2020
Subjects: subject: Computational Geometry (cs.CG)
subject: Robotics (cs.RO)
subject: FOS: Computer and information sciences

description: This paper presents Polylidar, an efficient algorithm to extract non-convex polygons from 2D point sets, including interior holes. Plane segmented point clouds can be input into Polylidar to extract their polygonal counterpart, thereby reducing map size and improving visualization. The algorithm begins by triangulating the point set and filtering triangles by user configurable parameters such as triangle edge length. Next, connected triangles are extracted into triangular mesh regions representing the shape of the point set. Finally each region is converted to a polygon through a novel boundary following method which accounts for holes. Real-world and synthetic benchmarks are presented to comparatively evaluate Polylidar speed and accuracy. Results show comparable accuracy and more than four times speedup compared to other concave polygon extraction methods.
description: 8 pages, 9 Figures
Additional file 3 of Cloacal swabs and alcohol bird specimens are good proxies for compositional analyses of gut microbial communities of Great tits (Parus major)
Creators: name: Kasun H. Bodawatta
name: Puzejova, Katerina
name: Sam, Katerina
name: Poulsen, Michael
name: Jønsson, Knud A.
Publisher: name: figshare
Year: 2020
Subjects: subject: Microbiology
subject: FOS: Biological sciences

description: Additional file 3: Figure S1. NMDS plots of microbial community similarities between different gut sections of fresh and differently aged alcohol samples. Ellipses represent 95% confidence intervals.
The upper limit of the e+e- partial width of X(3872)
Creators: name: Yuan, C. Z.
name: Mo, X. H.
name: Wang, P.
Publisher: name: arXiv
Year: 2003
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: The e+e- decay partial width of the recently observed state, X(3872), is estimated using the ISR data collected at the center of mass energy 4.03 GeV in e+e- annihilation experiment by BES at BEPC. It is found that the product of the e+e- partial width and X(3872) --> pi+ pi- J/psi decay branching fraction is less than 10 eV at 90 % confidence level if the J(PC) of X(3872) is 1(--). Together with the potential models and other information, we conclude that X(3872) is very unlikely to be a vector state.
description: 5 pages, 1 figure
Additional file 2 of Cloacal swabs and alcohol bird specimens are good proxies for compositional analyses of gut microbial communities of Great tits (Parus major)
Creators: name: Kasun H. Bodawatta
name: Puzejova, Katerina
name: Sam, Katerina
name: Poulsen, Michael
name: Jønsson, Knud A.
Publisher: name: figshare
Year: 2020
Subjects: subject: Microbiology
subject: FOS: Biological sciences

description: Additional file 2: Table S2. Results of pairwiseAdonis analysis between gut microbial communities of major gut regions [the stomach, the midgut (the small intestine and the cecum), and the hindgut (large intestine and cloaca)] and cloacal swabs. Asterisks indicate sections that were significantly different in composition. Table S3. The results of pairwiseAdonis analyses using Jaccard distances between gut microbial communities of different regions of the digestive tract (including cloacal swabs). Table S4. Summary of one-way analysis of variance (ANOVA) on OTU richness (R), Chao1 richness estimate (C), Shannon’s diversity index (Sh) and Inverse Simpson’s diversity index (Isimp) of freshly dissected gut sections and alcohol preserved specimens. Table S6. Museum ID numbers (Natural History Museum of Denmark), sexes and treatments (freshly dissected, two-weeks old alcohol specimens and two-months old alcohol specimens) of the 19 P. major used in this study.
Sequence-Selection-Based Constellation Shaping for Nonlinear Channels
Creators: name: Civelli, Stella
name: Forestieri, Enrico
name: Secondini, Marco
Publisher: name: arXiv
Year: 2023
Subjects: subject: Information Theory (cs.IT)
subject: Signal Processing (eess.SP)
subject: FOS: Computer and information sciences
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: Probabilistic shaping is a pragmatic approach to improve the performance of coherent optical fiber communication systems. In the nonlinear regime, the advantages offered by probabilistic shaping might increase thanks to the opportunity to obtain an additional nonlinear shaping gain. Unfortunately, the optimization of conventional shaping techniques, such as probabilistic amplitude shaping (PAS), yields a relevant nonlinear shaping gain only in scenarios of limited practical interest. In this manuscript we use sequence selection to investigate the potential, opportunities, and challenges offered by probabilistic shaping for nonlinear channels. First, we show that ideal sequence selection is able to provide up to 0.13 bit/s/Hz gain with respect to PAS with an optimized blocklength. However, this additional gain is obtained only if the selection metric accounts for the signs of the symbols: they must be known to compute the selection metric, but there is no need to shape them. Furthermore, we show that the selection depends in a non-critical way on the symbol rate and link length: the sequences selected for a certain scenario still provide a relevant gain if these are modified. Then, we analyze and compare several practical implementations of sequence selection by taking into account interaction with forward error correction (FEC) and complexity. Overall, the single block and the multi block FEC-independent bit scrambling are the best options, with a gain up to 0.08 bit/s/Hz. The main challenge and limitation to their practical implementation remains the evaluation of the metric, whose complexity is currently too high. Finally, we show that the nonlinear shaping gain provided by sequence selection persists when carrier phase recovery is included.
description: The manuscript is published on the Journal of Lightwave Technology
Local Radiative Hydrodynamic and Magnetohydrodynamic Instabilities in Optically Thick Media
Creators: name: Blaes, Omer
name: Socrates, Aristotle
Publisher: name: arXiv
Year: 2003
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We examine the local conditions for radiative damping and driving of short wavelength, propagating hydrodynamic and magnetohydrodynamic (MHD) waves in static, optically thick, stratified equilibria. We show that so-called strange modes in stellar oscillation theory and magnetic photon bubbles are intimately related and are both fundamentally driven by the background radiation flux acting on compressible waves. We identify the necessary criteria for unstable driving of these waves, and show that this driving can exist in both gas and radiation pressure dominated media, as well as pure Thomson scattering media in the MHD case. The equilibrium flux acting on opacity fluctuations can drive both hydrodynamic acoustic waves and magnetosonic waves unstable. In addition, magnetosonic waves can be driven unstable by a combination of the equilibrium flux acting on density fluctuations and changes in the background radiation pressure along fluid displacements. We briefly describe the conditions under which these instabilities might be manifested in both main sequence stellar envelopes and accretion disks.
description: 55 pages, revised version accepted for publication by ApJ. New appendix added justifying WKB analysis
Diadasia (Dasiapis) tropicalis BCP (CARCIB
Creators: name: Pedro, Diego De
name: Ceccarelli, Fadia Sara
name: Sagot, Philippe
name: López-Reyes, Eulogio
name: Mullins, Jessica L.
name: Mérida-Rivas, Jorge A.
name: Falcon-Brindis, Armando
name: Griswold, Terry
name: Ascher, John S.
name: Gardner, Joel
name: Ayala, Ricardo
name: Vides-Borrell, Eric
name: Vandame, Rémy
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy

description: Diadasia (Dasiapis) tropicalis (Cockerell, 1918) *
[♀ Pueblo Viejo, Veracruz, Mexico; December 8, 1909]
This species is primarily restricted to Neotropical regions and it constitutes a new record on the BCP. This species specializes on pollen from plants in the genus Sida L. (Malvaceae) (Sipes & Tepedino 2005). It was first recorded in the Gulf Coast ecoregion of BCS in 2017 by the CARCIB team. See fig. 98.
description: Published as part of Pedro, Diego De, Ceccarelli, Fadia Sara, Sagot, Philippe, López-Reyes, Eulogio, Mullins, Jessica L., Mérida-Rivas, Jorge A., Falcon-Brindis, Armando, Griswold, Terry, Ascher, John S., Gardner, Joel, Ayala, Ricardo, Vides-Borrell, Eric & Vandame, Rémy, 2024, Revealing the Baja California Peninsula's Hidden Treasures: An Annotated checklist of the native bees (Hymenoptera: Apoidea: Anthophila), pp. 1-391 in Zootaxa 5522 (1) on page 163, DOI: 10.11646/zootaxa.5522.1.1, http://zenodo.org/record/13920532
Monitoring temperature trends in Antarctica using GPS radio occultation
Creators: name: Adame, Erick
name: Kuo, Ying-Hwa
name: Schreiner, William
name: Rocken, Christian
name: Page, Michael
Publisher: name: University Corporation For Atmospheric Research (UCAR)
Year: 2004

In late 2005, the US-Taiwan joint satellite mission known as the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) will launch six Low Earth Orbit (LEO) satellites. These satellites, each equipped with an advanced Global Positioning System (GPS) receiver, will use radio occultation (RO) limb sounding technology to profile the Earthâs atmosphere with unprecedented accuracy and vertical resolution. The GPS RO soundings available from COSMIC will make significant contributions to global weather prediction, ionospheric research, and climate monitoring. The GPS receivers will measure the phase and amplitude. From that we can deduce the bending angles as a function of height, and obtain vertical profiles of refractivity using the Abel inversion under the local spherical symmetry assumption. To demonstrate the potential value of GPS RO data in climate monitoring, we analyzed GPS RO data obtained from a recent single-satellite German mission, known as the CHAllenging Mini Payload for Geophysical Research and Application (CHAMP). This study examined the monthly mean temperatures over the Antarctic using the CHAMP GPS RO data, provided by UCARâs COSMIC Data Analysis and Archive Center (CDAAC), from June 2001 through present. Seasonal and annual variations of tropopause temperature and altitude were analyzed, as well as the cooling/warming trends in the troposphere and stratosphere. These trends and variations were compared against similar analyses derived from the radiosonde data and the ECMWF and NCEP global analyses. Results show that GPS data can be used to assess the accuracy of global analyses and radiosonde data. This study highlights the usefulness of GPS RO data in climate monitoring.
Constructing comparative advantage: How India is moving up the global software value chain
Creators: name: Landi, Christina Melhorn
Publisher: name: American University
Year: 2023

description: The Indian IT industry has achieved higher value-added positions in the global IT value chain. This has important implications for considering opportunities for the South in the global economy, How private Indian firms and associations have moved firms up the global value chain was explored through the use of semi-structured interviews and business data analysis, Instead of relying on relatively lower labor costs, firms succeeded in: (1) building an international reputation for quality and delivery; (2) upgrading human capital; (3) overcoming market entrance costs and barriers; and (4) adding new markets and new clients. In doing so, firms constructed comparative advantage, by creating new advantages, upgrading existing factors and changing constraints, as opposed to taking resource endowments as given and somewhat fixed. Industry associations have assisted private firms by creating an enabling policy environment. Although often dismissed as narrowly representing the self-interest of a few large firms, Indian IT associations---for the hardware, software, Internet and telecom sectors---are representative of their industries and in broad agreement with the state as to industry objectives. Associations aid firms by intervening in the gap between stated policy objectives, written policies and their implementation to guide the state to remove impediments to growth and competition. Together, firms and associations' construction of comparative advantage targeted at a global value chain provides a concrete roadmap for countries of the South to navigate the global economy.
Critical phase induced by Berry phase and dissipation in a spin chain
Creators: name: Martin, Simon
name: Grover, Tarun
Publisher: name: arXiv
Year: 2023
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: Motivated by experiments on spin chains embedded in a metallic bath, as well as closed quantum systems described by long-range interacting Hamiltonians, we study a critical SU(N) spin chain perturbed by dissipation, or equivalently, after space-time rotation, long-range spatial interactions. The interplay of dissipation and the Wess-Zumino (Berry phase) term results in a rich phase diagram with multiple renormalization-group fixed points. For a range of the exponent that characterizes the dissipative bath, we find a second-order phase transition between the fixed point that describes an isolated critical spin chain and a dissipation-induced-ordered phase. More interestingly, for a different range of the exponent, we find a stable, gapless, nonrelativistic phase of matter whose existence necessarily requires coupling to the dissipative bath. Upon tuning the exponent, we find that the fixed point corresponding to this gapless, stable phase "annihilates" the fixed point that describes the transition out of this phase to the ordered phase. We also study a relativistic version of our model, and we identify a new critical point. We discuss the implications of our work for Kondo lattice systems and engineered long-range interacting quantum systems.
description: 6 pages main text, 4 figures (published version)
Stochastic and Discrete Time Models of Long-Range Turbulent Transport in the Scrape-Off Layer
Creators: name: Volchenkov, D.
name: Lima, R.
Publisher: name: arXiv
Year: 2004
Subjects: subject: Plasma Physics (physics.plasm-ph)
subject: FOS: Physical sciences

description: Two dimensional stochastic time model of scrape-off layer (SOL) turbulent transport is studied. Instability arisen in the system with respect to the stochastic perturbations of both either density or vorticity reveals itself in the strong outward bursts of particle density propagating ballistically across the SOL. The stability and possible stabilization of the cross- field turbulent system depend very much upon the reciprocal correlation time between density and vorticity fluctuations. Pdf of the particle flux for the large magnitudes of flux events can be modelled with a simple discrete time toy model of random walks concluding at a boundary. The spectra of wandering times feature the pdf of particle flux in the model and qualitatively reproduce the experimental statistics of transport events.
description: 21 pages,11 figures
Oxidation mechanisms for toluene under atmospheric conditions
Creators: name: Blazer, Cherelle
name: Orlando, John
name: Tyndall, Geoffrey
name: Holland, Marika
name: Cancel, Roberto
Publisher: name: University Corporation For Atmospheric Research (UCAR)
Year: 2004

A mesoscale convective system (MCS) is a complex of thunderstorms that is organized on a much larger scale than an individual thunderstorm and can persist for several hours. MCS characteristics (intensity, structure, propagation speed) are thought to be influenced by the thermodynamic properties of the environment and vertical wind shear. Past studies have typically characterized MCS environments on the basis of a single sounding, but there are few studies using detailed thermodynamic measurements of the environments of these systems to validate this approach. Data for this study were from the Bow Echo and Mesoscale Convective Vortices Experiment (BAMEX) to investigate the thermodynamic environment a convective system. This research was unique because there were approximately 35 soundings taken within and near this convective system. To quantify the environmental structure, selected parameters were used to estimate the buoyancy of hypothetically lifted parcels at several levels and the vertical wind shear through the lower and middle troposphere. Results suggest that the northern limit of the MCS is determined by environmental stability, not by processes internal to the MCS. There were significant differences in the intensity of the MCS between the northern and southern halves of the MCS that corresponded to the variation of the lifted index north to south. The variance of soundings in the path of the MCS suggests that it is not possible to characterize the degree of instability in this case. Furthermore, there was nearly a factor of two uncertainties in environmental wind shear. The results of this research further the understanding of the thermodynamic environment of a mesoscale convective system.
Investigating the thermodynamic environment of a mesoscale convective system
Creators: name: Burt, Melissa
name: Davis, Christopher
name: Wade, Nancy
Publisher: name: University Corporation For Atmospheric Research (UCAR)
Year: 2004

A mesoscale convective system (MCS) is a complex of thunderstorms that is organized on a much larger scale than an individual thunderstorm and can persist for several hours. MCS characteristics (intensity, structure, propagation speed) are thought to be influenced by the thermodynamic properties of the environment and vertical wind shear. Past studies have typically characterized MCS environments on the basis of a single sounding, but there are few studies using detailed thermodynamic measurements of the environments of these systems to validate this approach. Data for this study were from the Bow Echo and Mesoscale Convective Vortices Experiment (BAMEX) to investigate the thermodynamic environment a convective system. This research was unique because there were approximately 35 soundings taken within and near this convective system. To quantify the environmental structure, selected parameters were used to estimate the buoyancy of hypothetically lifted parcels at several levels and the vertical wind shear through the lower and middle troposphere. Results suggest that the northern limit of the MCS is determined by environmental stability, not by processes internal to the MCS. There were significant differences in the intensity of the MCS between the northern and southern halves of the MCS that corresponded to the variation of the lifted index north to south. The variance of soundings in the path of the MCS suggests that it is not possible to characterize the degree of instability in this case. Furthermore, there was nearly a factor of two uncertainties in environmental wind shear. The results of this research further the understanding of the thermodynamic environment of a mesoscale convective system.
Invariant theory and scaling algorithms for maximum likelihood estimation
Creators: name: Améndola, Carlos
name: Kohn, Kathlén
name: Reichenbach, Philipp
name: Seigal, Anna
Publisher: name: arXiv
Year: 2020
Subjects: subject: Statistics Theory (math.ST)
subject: Algebraic Geometry (math.AG)
subject: FOS: Mathematics
subject: 14L24, 14P05, 20G45, 62F10, 62H22, 62R01

description: We uncover connections between maximum likelihood estimation in statistics and norm minimization over a group orbit in invariant theory. We focus on Gaussian transformation families, which include matrix normal models and Gaussian graphical models given by transitive directed acyclic graphs. We use stability under group actions to characterize boundedness of the likelihood, and existence and uniqueness of the maximum likelihood estimate. Our approach reveals promising consequences of the interplay between invariant theory and statistics. In particular, existing scaling algorithms from statistics can be used in invariant theory, and vice versa.
description: 34 pages; The discrete part on log-linear models from version 1 is contained in the companion paper arXiv:2012.07793. (v4: very minor changes compared to v3)
Characterization of diurnal variation of the boundary layer structure in complex terrain
Creators: name: Cancel, Roberto
name: Sun, Jielun
name: Curtis, Laura
Publisher: name: University Corporation For Atmospheric Research (UCAR)
Year: 2004

The Niwot Ridge has been the site of numerous chemical transport and spatial distribution studies, including the 2004 Carbon in the Mountains Experiment (CME); however, an in-depth characterization and understanding of the wind structure of this complex terrain does not exist. The CME will investigate the accuracy of carbon dioxide (COâ) measurements in complex terrains (i.e. mountains, forests). Utilizing satellite data, Schimel determined that 25 to 50% of total US carbon uptake, and up to 75% of total Western US uptake, occurs in mountainous terrain. Because turbulence is one of the transport processes and the boundary layer plays an integral role in transport and spatial distribution of chemicals, this study investigated the diurnal variation of the boundary layer structure in the Niwot Ridge utilizing a SODAR (sonic detection and ranging). Data from the SODAR was collected from March 15 to July 7, 2004 with measurements every 10 to 15 minutes. Plots of the wind profiles were generated and analyzed utilizing synoptic meteorological conditions at the site. The study found that the diurnal variation of wind speed and direction vary directly with the diurnal cycle of the boundary layer structure. Much of the dataset was found to have "bad" or missing data; in fact, some days had 50 to 70% bad or missing data. This was partially attributed to the diurnal cycle of the boundary layer structure and nature of the investigated site. Further analysis of the diurnal variation of boundary layer structure in complex terrain is necessary.
Synoptic analysis of 2001-2004 "Long Rains" on Mt. Kilimanjaro
Creators: name: Chan, Rebecca
name: Ammann, Caspar
name: Yin, Jeff
name: Book, Christina
name: Pandya, Rajul
Publisher: name: University Corporation For Atmospheric Research (UCAR)
Year: 2004

Recently, ice cores covering the last 10,000 years have been recovered from Mt. Kilimanjaro. Past studies have suggested that East African precipitation is primarily driven by local-scale processes rather than large-scale atmospheric circulation. Interestingly, the changes seen in the Kilimanjaro ice cores resemble closely other climatic records from a large area in Africa as well as the Indian monsoon areas. So far, studies are further complicated by the lack of in situ data. To advance the understanding of modern East African climate, this study focused on new station data directly from the summit of Mt. Kilimanjaro. First, these local measurements were compared with NCEP/NCAR reanalysis data to verify the usefulness of the global reanalysis in this particular region. Overall, the correspondence was reasonably good, opening the possibility for future studies to expand the time frame over the past 50 years. Second, the use of both data sets allowed for an examination of the commonalities of precipitation events during the âlong rainsâ season (February-May) in 2001-2004 on Mt. Kilimanjaro and identified the key precipitation-causing processes. Results suggest that Kilimanjaro precipitation is related to strong convective activity over the Indian Ocean near Madagascar accompanied with anomalous airflow towards the continent where strong rising motion is responsible for the precipitation. In addition, the Indian Ocean appears to be the dominant source of moisture for Mt. Kilimanjaro snowfall. These findings provide a preliminary interpretation of the governing processes that control precipitation events on Mt. Kilimanjaro, which contributes to a better understanding of current regional climate and aids in an improved interpretation of paleoclimatic records.
Constructing comparative advantage: How India is moving up the global software value chain
Creators: name: Landi, Christina Melhorn
Publisher: name: ProQuest
Year: 2023
Subjects: classificationCode: 35
subject: Commerce, management, tourism and services

description: The Indian IT industry has achieved higher value-added positions in the global IT value chain. This has important implications for considering opportunities for the South in the global economy, How private Indian firms and associations have moved firms up the global value chain was explored through the use of semi-structured interviews and business data analysis, Instead of relying on relatively lower labor costs, firms succeeded in: (1) building an international reputation for quality and delivery; (2) upgrading human capital; (3) overcoming market entrance costs and barriers; and (4) adding new markets and new clients. In doing so, firms constructed comparative advantage, by creating new advantages, upgrading existing factors and changing constraints, as opposed to taking resource endowments as given and somewhat fixed. Industry associations have assisted private firms by creating an enabling policy environment. Although often dismissed as narrowly representing the self-interest of a few large firms, Indian IT associations---for the hardware, software, Internet and telecom sectors---are representative of their industries and in broad agreement with the state as to industry objectives. Associations aid firms by intervening in the gap between stated policy objectives, written policies and their implementation to guide the state to remove impediments to growth and competition. Together, firms and associations' construction of comparative advantage targeted at a global value chain provides a concrete roadmap for countries of the South to navigate the global economy.
Reducing financial impacts on the reinsurance industry: Economic valuation of seasonal hurricane forecasts
Creators: name: Coleman, D.
name: Katz, Richard
name: Olson, Katherine
Publisher: name: University Corporation For Atmospheric Research (UCAR)
Year: 2004

Hurricanes can cause significant economic loss in the eastern coastal United States. Forecasts of seasonal hurricane frequency and intensity are available, but the use of these forecasts in the reinsurance industry to mitigate the economic impacts of hurricane landfall is not apparent. If reinsurance utilized forecasts, they could conceivably increase the likelihood of being able to pay insurance companies in the event of a damaging hurricane strike. This would also benefit insurance companies and property owners by stabilizing the insurance industry as a whole. We first analyzed the dependence of hurricane frequency and damage on El Niño-Southern Oscillation (ENSO). Results indicated that La Niña (El Niño) years experience more (less) frequent, more (less) damaging hurricanes. We then built a simulation model of damage. Assuming knowledge of the ENSO state, the model generated annual total damage based on adjusted Poisson and lognormal distributions of annual hurricane number and storm damage, respectively. We obtained the 5% level of loss exceedance associated with all, La Niña, Neutral, and El Niño years. They showed 20-year period return levels of $33.7, 73.2, 30.1, and 9.9 billion, respectively (constant 1995$). ENSO state appears to have a considerable effect on the distribution of economic damage. Through the model's inclusion of specific reinsurance contract options (and associated costs) and a complete hurricane forecast (i.e. not just the ENSO aspect of the forecast), the optimal use and forecast value to the industry could be quantified. This This would also benefit insurance companies and property owners by stabilizing the insurance industry as a whole. We first analyzed the dependence of hurricane frequency and damage on El Niño-Southern Oscillation (ENSO). Results indicated that La Niña (El Niño) years experience more (less) frequent, more (less) damaging hurricanes. We then built a simulation model of damage. Assuming knowledge of the ENSO state, the model generated annual total damage based on adjusted Poisson and lognormal distributions of annual hurricane number and storm damage, respectively. We obtained the 5% level of loss exceedance associated with all, La Niña, Neutral, and El Niño years. They showed 20-year period return levels of $33.7, 73.2, 30.1, and 9.9 billion, respectively (constant 1995$). ENSO state appears to have a considerable effect on the distribution of economic damage. Through the model’s inclusion of specific reinsurance contract options (and associated costs) and a complete hurricane forecast (i.e. not just the ENSO aspect of the forecast), the optimal use and forecast value to the industry could be quantified.
From Large to Small Scales: Global Models of the ISM
Creators: name: de Avillez, M.
name: Breitschwerdt, D.
Publisher: name: arXiv
Year: 2003
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We review large scale modelling of the ISM with emphasis on the importance to include the disk-halo-disk duty cycle and to use a dynamical refinement of the grid (in regions where steep variations of density and pressure occur) for a realistic modelling of the ISM. We also discuss the necessity of convergence of the simulation results by comparing 0.625, 1.25 and 2.5 pc resolution simulations and show that a minimum grid resolution of 1.25 pc is required for quantitatively reliable results, as there is a rapid convergence for Delta x \leq 1.1 pc.
description: 10 pages, 8 figures that include 2 simulation images (in jpeg format) and 6 plots (4 in ps and 2 in jpeg formats), to appear in the proceedings of ``From Observations to Self-Consistent Modelling of the ISM in Galaxies'', Kluwer
"They have to take the long way to the shortcut, too": The politics of solidarity and identity
Creators: name: O'Brien, Erin Elizabeth
Publisher: name: American University
Year: 2023

description: This project investigates the social and psychological processes that produce, or fail to produce, feelings of solidarity and mutual commitment across social groups. Critics of "identity politics" frequently charge identifying strongly along one identity poses a barrier to collective solidarity and coalition building. They allege, for example, that when a black woman develops group consciousness around her particular identities (as a woman and/or African American) two things are likely to happen. First, she will become less likely to feel solidarity with a group in which she is not a member, such as Hispanic-Americans. Second, she will become less likely to identify politically with a broader, more diverse group in which she is a member, such as the one defined by her social class. Similar expectations can be derived from traditional forms of social identity theory. This project offers an empirical evaluation of such claims and contrasts them with competing hypotheses derived from cognitive development theories. It illuminates how individuals develop, or fail to develop, various forms of solidarity as well as how feelings of group identification and group consciousness may influence these processes. In order to address these interpretivist questions, data is drawn from a comparative case study of low-wage service workers with, and without, feelings of group identification and/or group consciousness. Data collection involved 10 months of participant observation in a low-wage service job and 48 in-depth, semi-structured interviews with a purposive sample of low-wage service workers. Interviews were transcribed verbatim and then coded and interpreted them with the assistance of a software package for qualitative analysis (QSR N5).
Diadasia (Diadasia) enavata BC (MABC
Creators: name: Pedro, Diego De
name: Ceccarelli, Fadia Sara
name: Sagot, Philippe
name: López-Reyes, Eulogio
name: Mullins, Jessica L.
name: Mérida-Rivas, Jorge A.
name: Falcon-Brindis, Armando
name: Griswold, Terry
name: Ascher, John S.
name: Gardner, Joel
name: Ayala, Ricardo
name: Vides-Borrell, Eric
name: Vandame, Rémy
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy

description: Diadasia (Diadasia) enavata (Cresson, 1872)
[♀ Bosque Co., Texas, USA]
Diadasia enavata is widely spread across western North America. This species specializes on pollen in the tribe Heliantheae (Asteraceae) (Sipes & Tepedino 2005). Cockerell (1899) reported this species in Comondú, BCS. The ECOAB team collected this species (4 ♂) for the first time in BC in the Lower Colorado Desert in June 2019, and the MABC team collected three males in the Coastal Sage Matorral in June 2020. See fig. 98.
description: Published as part of Pedro, Diego De, Ceccarelli, Fadia Sara, Sagot, Philippe, López-Reyes, Eulogio, Mullins, Jessica L., Mérida-Rivas, Jorge A., Falcon-Brindis, Armando, Griswold, Terry, Ascher, John S., Gardner, Joel, Ayala, Ricardo, Vides-Borrell, Eric & Vandame, Rémy, 2024, Revealing the Baja California Peninsula's Hidden Treasures: An Annotated checklist of the native bees (Hymenoptera: Apoidea: Anthophila), pp. 1-391 in Zootaxa 5522 (1) on page 163, DOI: 10.11646/zootaxa.5522.1.1, http://zenodo.org/record/13920532
Directional Tunneling Escape from Nearly Spherical Optical Resonators
Creators: name: Lacey, Scott
name: Wang, Hailin
name: Foster, David H.
name: Noeckel, Jens U.
Publisher: name: arXiv
Year: 2003
Subjects: subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: We report the surprising observation of directional tunneling escape from nearly spherical fused-silica optical resonators, in which most of the phase space is filled with nonchaotic regular trajectories. Experimental and theoretical studies of the dependence of the far-field emission pattern on both the degree of deformation and the excitation condition show that nonperturbative phase-space structures in the internal ray dynamics profoundly affect tunneling leakage of the whispering-gallery modes.
description: 5 pages, 2 figures
RoseNNa: A performant, portable library for neural network inference with application to computational fluid dynamics
Creators: name: Bati, Ajay
name: Bryngelson, Spencer H.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Fluid Dynamics (physics.flu-dyn)
subject: Machine Learning (cs.LG)
subject: FOS: Physical sciences
subject: FOS: Computer and information sciences

description: The rise of neural network-based machine learning ushered in high-level libraries, including TensorFlow and PyTorch, to support their functionality. Computational fluid dynamics (CFD) researchers have benefited from this trend and produced powerful neural networks that promise shorter simulation times. For example, multilayer perceptrons (MLPs) and Long Short Term Memory (LSTM) recurrent-based (RNN) architectures can represent sub-grid physical effects, like turbulence. Implementing neural networks in CFD solvers is challenging because the programming languages used for machine learning and CFD are mostly non-overlapping, We present the roseNNa library, which bridges the gap between neural network inference and CFD. RoseNNa is a non-invasive, lightweight (1000 lines), and performant tool for neural network inference, with focus on the smaller networks used to augment PDE solvers, like those of CFD, which are typically written in C/C++ or Fortran. RoseNNa accomplishes this by automatically converting trained models from typical neural network training packages into a high-performance Fortran library with C and Fortran APIs. This reduces the effort needed to access trained neural networks and maintains performance in the PDE solvers that CFD researchers build and rely upon. Results show that RoseNNa reliably outperforms PyTorch (Python) and libtorch (C++) on MLPs and LSTM RNNs with less than 100 hidden layers and 100 neurons per layer, even after removing the overhead cost of API calls. Speedups range from a factor of about 10 and 2 faster than these established libraries for the smaller and larger ends of the neural network size ranges tested.
description: 10 pages, 4 figures
Monitoring and Reliability System (MARS)
Creators: name: Craft, Tanya
name: Engel, Thomas
name: Bevirt, Brian
Publisher: name: University Corporation For Atmospheric Research (UCAR)
Year: 2004

The National Science Foundation (NSF) funds the National Center for Atmospheric Research (NCAR). The Scientific Computing Division (SCD) is responsible for monitoring the purchases and administering computational equipment funded by the NSF. One of these systems is bluesky, which was purchased from IBM with the stipulation that its uptime be 98%. However, SCD was required to make sure that bluesky maintained the necessary level of reliability. This is important to NCAR and NSF because the availability of the supercomputer to users needs to be high for maximum productivity. Therefore, research was conducted to create a reliability-reporting utility that would monitor and report the reliability of bluesky based on the records of bluesky problems stored in SCD’s Trouble Ticket Database. The reliability-reporting utility has three parts: a perl program that calculates various reliability metrics of bluesky on an “on demand” basis, Microsoft Excel graphs based on the values from the calculations of the program, and Microsoft Word files that combine the calculations and graphs into webpages. All of these are combined to form a website. This allows the reliability of bluesky to be routinely tracked to assure it is achieving the highest level of productivity. It also helps decision makers assess how different kinds of problems affect bluesky’s reliability. Further, this utility can also be used for tracking the productivity of all of NCAR’s supercomputers.
Evaluating various wind measurement and retrival schemes used for the Pentagon Shield Project
Creators: name: Didlake, Anthony
name: Crook, Andrew
name: Ramamurthy, Mohan
name: Holland, Beth
name: Craft, Tanya
Publisher: name: University Corporation For Atmospheric Research (UCAR)
Year: 2004

The Pentagon Shield Project is an antiterrorist initiative to develop a system that models and predicts the dispersion of airborne toxins around the Pentagon. This system will depend on wind measuring instruments and estimation, or retrieval, techniques to provide input to dispersion models. A field experiment conducted in April-May 2004 used a number of wind measuring instruments and retrieval techniques to examine the local airflow. This study evaluated the accuracy of two measuring instruments, Doppler lidar (a laser-based radar) and SODAR (SOund Detection And Ranging), and three retrieval techniques to determine which schemes provide the most reliable wind profiles. The data were compared by separating the observed and retrieved wind vectors into two components, the radial and azimuthal components. A least-square fit comparison of the radial wind components from the lidar and SODAR showed that the SODAR-measured winds were slightly higher than those measured by the lidar. The azimuthal wind components were used to verify the retrieval techniques, Velocity-Azimuth Display (VAD) and two variations of Velocity Volume Processing (VVP-1, VVP-2). Our results showed that the VAD method breaks down for the small sectors of data that were collected over the Pentagon. VVP-1 and VVP-2 perform least-square curve fitting on radial wind data but over different sectors. The results showed that VVP-2 gives a better estimate of the average wind over larger areas. Evaluating these schemes is important not only for the Pentagon Shield Project, but for other studies that use similar instruments and techniques to examine wind fields.
Topology Optimization for Uniform Flow Distribution in Electrolysis Cells
Creators: name: Baeck, Leon
name: Blauth, Sebastian
name: Leithäuser, Christian
name: Pinnau, René
name: Sturm, Kevin
Publisher: name: arXiv
Year: 2023
Subjects: subject: Optimization and Control (math.OC)
subject: FOS: Mathematics

description: In this paper we consider the topology optimization for a bipolar plate of a hydrogen electrolysis cell. We present a model for the bipolar plate using the Stokes equation with an additional drag term, which models the influence of fluid and solid regions. Furthermore, we derive a criterion for a uniform flow distribution in the bipolar plate. To obtain shapes that are well-manufacturable, we introduce a novel smoothing technique for the fluid velocity. Finally, we present some numerical results and investigate the influence of the smoothing on the obtained shapes.
Impact of collision models on the physical properties and the stability of lattice Boltzmann methods
Creators: name: Coreixas, C.
name: Wissocq, G.
name: Chopard, B.
name: Latt, J.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Computational Physics (physics.comp-ph)
subject: FOS: Physical sciences

description: The lattice Boltzmann method (LBM) is known to suffer from stability issues when the collision model relies on the BGK approximation, especially in the zero viscosity limit and for non-vanishing Mach numbers. To tackle this problem, two kinds of solutions were proposed in the literature. They consist in changing either the numerical discretization (finite-volume, finite-difference, spectral-element, etc) of the discrete velocity Boltzmann equation (DVBE), or the collision model. In this work, the latter solution is investigated in details. More precisely, we propose a comprehensive comparison of (static relaxation time based) collision models, in terms of stability, and with preliminary results on their accuracy, for the simulation of isothermal high-Reynolds number flows in the (weakly) compressible regime. It starts by investigating the possible impact of collision models on the macroscopic behavior of stream-and-collide based D2Q9-LBMs, which clarifies the exact physical properties of collision models on LBMs. It is followed by extensive linear and numerical stability analyses, supplemented with an accuracy study based on the transport of vortical structures over long distances. In order to draw conclusions as general as possible, the most common moment spaces (raw, central, Hermite, central Hermite and cumulant), as well as regularized approaches, are considered for the comparative studies. LBMs based on dynamic collision mechanisms (entropic collision, subgrid scale models, explicit filtering, etc) are also briefly discussed.
"They have to take the long way to the shortcut, too": The politics of solidarity and identity
Creators: name: O'Brien, Erin Elizabeth
Publisher: name: ProQuest
Year: 2023
Subjects: classificationCode: 44
subject: Human society
classificationCode: 4408
subject: Political science
subject: FOS: Political science

description: This project investigates the social and psychological processes that produce, or fail to produce, feelings of solidarity and mutual commitment across social groups. Critics of "identity politics" frequently charge identifying strongly along one identity poses a barrier to collective solidarity and coalition building. They allege, for example, that when a black woman develops group consciousness around her particular identities (as a woman and/or African American) two things are likely to happen. First, she will become less likely to feel solidarity with a group in which she is not a member, such as Hispanic-Americans. Second, she will become less likely to identify politically with a broader, more diverse group in which she is a member, such as the one defined by her social class. Similar expectations can be derived from traditional forms of social identity theory. This project offers an empirical evaluation of such claims and contrasts them with competing hypotheses derived from cognitive development theories. It illuminates how individuals develop, or fail to develop, various forms of solidarity as well as how feelings of group identification and group consciousness may influence these processes. In order to address these interpretivist questions, data is drawn from a comparative case study of low-wage service workers with, and without, feelings of group identification and/or group consciousness. Data collection involved 10 months of participant observation in a low-wage service job and 48 in-depth, semi-structured interviews with a purposive sample of low-wage service workers. Interviews were transcribed verbatim and then coded and interpreted them with the assistance of a software package for qualitative analysis (QSR N5).
Who shall decide when doctors disagree? Hoaxes and American men of science in the nineteenth century
Creators: name: Stewart, Elizabeth Pritchard
Publisher: name: American University
Year: 2023

description: Self-proclaimed men of science perpetrated an extraordinary series of hoaxes in the U.S. in the 1830s through the 1880s, a period of intense popularization and professionalization of American science. This dissertation identifies the emergence of a pattern testing science's authority: hoaxers' orchestration of tricks actively engaged debunkers and spectators in parodies of the scientific method, forcing professionalizing scientists to confront what I have termed a "democracy of knowledge" among laypeople. Hoaxes injected humor into the tension between two as yet inchoate visions: the democracy of knowledge---a protean discourse rooted in mid-nineteenth-century values celebrating the wisdom of the common man---and rule by expert-scientists' conception of a modern future. Fascinated by the promise of science and technology, the public venerated charlatans and dabblers at science's fringes, whose spectacular attractions were most enjoyable for the layperson. Whether confronting the Moon Hoax, the Feejee Mermaid, spiritualism, or the Cardiff Giant in the proliferating venues of popular amusement, audiences eagerly participated in the working-out of the controversy provoked by each novel "discovery." While exercising their powers of detection, they expressed an expectation that they had as much right as anyone to determine the role of science in American life. For their part, nascent scientists debated among themselves whether to challenge the hoaxers at a time when any hint of fraud threatened to devalue their still fragile professional status. These men improvised a variety of responses across the nineteenth century: they met their adversaries head-on, with mixed results, or waged behind-the-scenes campaigns against the perpetrator of the day. This dissertation argues that in mid-nineteenth-century hoaxes men of science and average people negotiated the limits and benefits of scientific knowledge in American society, science's prestige to be enhanced or undercut in particular by elites' responses to deception. Scientists' lack of unanimity in meeting these popular challenges allowed the persistence of the belief that when "doctors" disagreed, the people ought to decide. This democracy of knowledge symbolically preserved laypeople's right to "do" science, and put scientists on notice that they could not expect complete freedom of action in the exercise of their expertise.