cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
The moment of first encounter: processes used by teachers of adults
Creators: name: Tyzack, H
Publisher: name: University Of Tasmania
Year: 2023

description: This exploratory study reports on the performance of teacher practitioners when first encountering a new class group of adult learners, within Tasmanian education and training institutions. It was conducted within a context of increasing numbers of adult learners in these organisations. The thesis is that there is insufficient understanding of what such practitioners bring to the moment of first encounter, and about what they do and the reasons for their activity in that first moment. In a qualitative study, a sample of 34 practitioners was interviewed and some of their learners contributed additional viewpoints. A mixed methods approach was the basis of the research design. The study explores how the prior knowledge, experience and personal paradigms, which adult practitioners bring to the moment of first face-to-face encounter with a new group of adult learners, are employed during the moment of first encounter. On the basis that ‚ÄövÑvªfirst impressions [may] count‚ÄövÑvº, this study investigates the observations, thinking and decision making activities of practitioners, during their moment of first encounter with new class groups. The study revealed that prior to the moment of first encounter, practitioners can be understood as containers of memories, experiences, and knowledge. As they journey into the moment of first encounter and meet a new group of adult learners, they are enriched by their baggage of knowledge stores and experiences gathered in different periods preceding that moment. The moment of first encounter is a time when practitioners reflect on their experience and retrieve a body of pre-existing knowledge and beliefs, some of which may be derived from a Familiarisation Routine. Collectively, this study labels these as a Foundation. In the moment of first encounter, practitioners proceed by executing a number of activities patterned into typical routines; a Discovery Routine, which flows instantly and automatically through a Transformation Routine then a Decision-making Routine. These seamlessly integrated Routines meet the needs of the present without compromising practitioners‚ÄövÑvº ability in future moments to meet their own needs. Regardless of the level of interest in and care about the group of learners, practitioners‚ÄövÑvº initially focus on their personal needs. The research found that the moment of first encounter is a scene-setting period where practitioners take stock of the learners as a group, in order to plan for a pathway that will reduce any of their own anxieties. The outcome from this study is a new understanding of the first activities that occur in a limited time period at the beginning of a practitioner‚ÄövÑvºs first meeting with a class group of adult learners, and an appreciation of a practitioner‚ÄövÑvºs initial thoughts and decisions. It is expected that the findings will assist with training those who propose to teach adult learners.
Forced and unforced variability of twentieth century North American droughts and pluvials
Creators: Cook, Benjamin I.
Cook, Edward R.
Anchukaitis, Kevin
Seager, Richard
Miller, Ronald L.
Publisher: name: Columbia University
Year: 2010
Subjects: Climatology
Hydrologic cycle
Droughts
Pluvial periods
Climatic changes

description: Research on the forcing of drought and pluvial events over North America is dominated by general circulation model experiments that often have operational limitations (e.g., computational expense, ability to simulate relevant processes, etc). We use a statistically based modeling approach to investigate sea surface temperature (SST) forcing of the twentieth century pluvial (1905-1917) and drought (1932-1939, 1948-1957, 1998-2002) events. A principal component (PC) analysis of Palmer Drought Severity Index (PDSI) from the North American Drought Atlas separates the drought variability into five leading modes accounting for 62% of the underlying variance. Over the full period spanning these events (1900-2005), the first three PCs significantly correlate with SSTs in the equatorial Pacific (PC 1), North Pacific (PC 2), and North Atlantic (PC 3), with spatial patterns (as defined by the empirical orthogonal functions) consistent with our understanding of North American drought responses to SST forcing. We use a large ensemble statistical modeling approach to determine how successfully we can reproduce these drought/pluvial events using these three modes of variability. Using Pacific forcing only (PCs 1-2), we are able to reproduce the 1948-1957 drought and 1905-1917 pluvial above a 95% random noise threshold in over 90% of the ensemble members; the addition of Atlantic forcing (PCs 1-2-3) provides only marginal improvement. For the 1998-2002 drought, Pacific forcing reproduces the drought above noise in over 65% of the ensemble members, with the addition of Atlantic forcing increasing the number passing to over 80%. The severity of the drought, however, is underestimated in the ensemble median, suggesting this drought intensity can only be achieved through internal variability or other processes. Pacific only forcing does a poor job of reproducing the 1932-1939 drought pattern in the ensemble median, and less than one third of ensemble members exceed the noise threshold (28%). Inclusion of Atlantic forcing improves the ensemble median drought pattern and nearly doubles the number of ensemble members passing the noise threshold (52%). Even with the inclusion of Atlantic forcing, the intensity of the simulated 1932-1939 drought is muted, and the drought itself extends too far into the southwest and southern Great Plains. To an even greater extent than the 1998-2002 drought, these results suggest much of the variance in the 1932-1939 drought is dependent on processes other than SST forcing. This study highlights the importance of internal noise and non SST processes for hydroclimatic variability over North America, complementing existing research using general circulation models.
Recursive tilings and space-filling curves with little fragmentation
Creators: name: Haverkort, Herman
Publisher: name: Journal of Computational Geometry
Year: 2011

description: This paper defines the Arrwwid number of a recursive tiling (or space-filling curve) as the smallest number a such that any ball Q can be covered by a tiles (or curve fragments) with total volume O(volume(Q)). Recursive tilings and space-filling curves with low Arrwwid numbers can be applied to optimize disk, memory or server access patterns when processing sets of points inRd. This paper presents recursive tilings and space-filling curves with optimal Arrwwid numbers. For d ≥ 3, we see that regular cube tilings and space-filling curves cannot have optimal Arrwwid number, and we see how to construct alternatives with better Arrwwid numbers.
description: Journal of Computational Geometry, Vol 2, No 1 (2011)
Contribution of anthropogenic warming to California drought during 2012–2014
Creators: Williams, A. Park
Seager, Richard
Abatzoglou, John T.
Cook, Benjamin I.
Smerdon, Jason E.
Cook, Edward R.
Publisher: name: Columbia University
Year: 2015
Subjects: Droughts
Climatic changes--Effect of human beings on
Atmosphere
Meteorology

description: A suite of climate data sets and multiple representations of atmospheric moisture demand are used to calculate many estimates of the self-calibrated Palmer Drought Severity Index, a proxy for near-surface soil moisture, across California from 1901 to 2014 at high spatial resolution. Based on the ensemble of calculations, California drought conditions were record breaking in 2014, but probably not record breaking in 2012–2014, contrary to prior findings. Regionally, the 2012–2014 drought was record breaking in the agriculturally important southern Central Valley and highly populated coastal areas. Contributions of individual climate variables to recent drought are also examined, including the temperature component associated with anthropogenic warming. Precipitation is the primary driver of drought variability but anthropogenic warming is estimated to have accounted for 8–27% of the observed drought anomaly in 2012–2014 and 5–18% in 2014. Although natural variability dominates, anthropogenic warming has substantially increased the overall likelihood of extreme California droughts.
Comparing proxy and model estimates of hydroclimate variability and change over the Common Era
Creators: PAGES Hydro2k Consortium
Smerdon, Jason E.
Cook, Benjamin I.
Mankin, Justin S.
Singh, Deepti
Steiger, Nathan J.
Andreu Hayles, Laia
Baek, Seung Hun
Buckley, Brendan M.
Cook, Edward R.
D'Arrigo, Rosanne Dorothy
Kushnir, Yochanan
Leland, Caroline Wogan
Rao, Mukund Palat
Scheff, Jacob S.
Seager, Richard
Williams, A. Park
Publisher: name: Columbia University
Year: 2017
Subjects: Paleoclimatology
Climatic changes
Environmental sciences
Hydrology
Paleoclimatology--Mathematical models

description: Water availability is fundamental to societies and ecosystems, but our understanding of variations in hydroclimate (including extreme events, flooding, and decadal periods of drought) is limited because of a paucity of modern instrumental observations that are distributed unevenly across the globe and only span parts of the 20th and 21st centuries. Such data coverage is insufficient for characterizing hydroclimate and its associated dynamics because of its multidecadal to centennial variability and highly regionalized spatial signature. High-resolution (seasonal to decadal) hydroclimatic proxies that span all or parts of the Common Era (CE) and paleoclimate simulations from climate models are therefore important tools for augmenting our understanding of hydroclimate variability. In particular, the comparison of the two sources of information is critical for addressing the uncertainties and limitations of both while enriching each of their interpretations. We review the principal proxy data available for hydroclimatic reconstructions over the CE and highlight the contemporary understanding of how these proxies are interpreted as hydroclimate indicators. We also review the available last-millennium simulations from fully coupled climate models and discuss several outstanding challenges associated with simulating hydroclimate variability and change over the CE. A specific review of simulated hydroclimatic changes forced by volcanic events is provided, as is a discussion of expected improvements in estimated radiative forcings, models, and their implementation in the future. Our review of hydroclimatic proxies and last-millennium model simulations is used as the basis for articulating a variety of considerations and best practices for how to perform proxy–model comparisons of CE hydroclimate. This discussion provides a framework for how best to evaluate hydroclimate variability and its associated dynamics using these comparisons and how they can better inform interpretations of both proxy data and model simulations. We subsequently explore means of using proxy–model comparisons to better constrain and characterize future hydroclimate risks. This is explored specifically in the context of several examples that demonstrate how proxy–model comparisons can be used to quantitatively constrain future hydroclimatic risks as estimated from climate model projections.
Physics of the interior of a black hole with an exotic scalar matter
Creators: name: Doroshkevich, Andrey
name: Hansen, Jakob
name: Novikov, Dmitriy
name: Novikov, Igor
name: Park, Dong-Ho
name: Shatskiy, Alexander
Publisher: name: arXiv
Year: 2009
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We use a numerical code to consider the nonlinear processes arising when a Reissner-Nordstrom black hole is irradiated by an exotic scalar field (modelled as a free massless scalar field with an opposite sign for its energy-momentum tensor). These processes are quite different from the processes arising in the case of the same black hole being irradiated by a pulse of a normal scalar field. In our case, we did not observe the creation of a spacelike strong singularity in the T-region of the space-time. We investigate the antifocusing effects in the gravity field of the exotic scalar field with the negative energy density and the evolution of the mass function. We demonstrate the process of vanishing of the black hole when it is irradiated by a strong pulse of an exotic scalar field.
description: 16 pages, 16 figures. Text has been rewritten and restructured, Penrose diagrams have been added, appendix with convergence tests has been added. Co-author has been added. Conclusions are unchanged
Points with large quadrant depth
Creators: name: Apfelbaum, Roel
name: Ben-Dan, Itay
name: Felsner, Stefan
name: Miltzow, Tillmann
name: Pinchasi, Rom
name: Ueckerdt, Torsten
name: Ziv, Ran
Publisher: name: Journal of Computational Geometry
Year: 2011

description: Given a set P of points in the plane we are interested in points that are `deep' in the set in the sense that they have two opposite quadrants both containing many points of P. We deal with an extremal version of this problem. A pair (a,b) of numbers is admissible if every point set P contains a point p in P that determines a pair (Q,Qop) of opposite quadrants, such thatQ contains at least an a-fraction and Qop contains at least a b-fraction of the points of P. We provide a complete description of the set F of all admissible pairs (a,b). This amounts to identifying three line segments and a point on the boundary of F. In higher dimensions we study the maximum a, such that (a,a) is opposite-orthant admissible. In dimension d we show that 1/(2γ)≤a≤1/γ for γ=22d-12d-1. Finally we deal with a variant of the problem where the opposite pairs of orthants need not be determined by a point in P. Again we are interested in values a, such that all subsets P inRd admit a pair (O,Oop) of opposite orthants both ontaining at least an a-fraction of the points. The maximum such value is a=1/2d. Generalizations of the problem are also disussed.
description: Journal of Computational Geometry, Vol 2, No 1 (2011)
Dendroarchaeological analysis of the Terminal Warehouse in New York City reveals a history of long-distance timber transport during the Gilded Age
Creators: Leland, Caroline Wogan
Rao, Mukund Palat
Cook, Edward R.
Cook, Benjamin I.
Lapidus, Bryan
Staniforth, Andrew
Solomon, Alan
Holloway, Marguerite Y.
Rodriguez-Caton, Milagros
Publisher: name: Columbia University
Year: 2021
Subjects: Dendrochronology
Tree-rings
Timber--Analysis
Building materials
Longleaf pine
Southern pines

description: The Gilded Age of the late 19th century marked a period of rapid development and urbanization in New York City, U.S. To accommodate the high demand in wood products during that time, the timbers used for development of the city were increasingly sourced from locations distant from the northeastern United States. The Terminal Warehouse in the Chelsea neighborhood of New York City was one of many large buildings erected during this period of city expansion, and is an important symbol of New York City commerce during the late 1800s. To determine the history and provenance of timbers used in the construction of the Terminal Warehouse, we used tree-ring analysis on longleaf pine (Pinus palustris Mill.) joists that were original to the building. The ring-width patterns on the joists crossdated well internally, suggesting a common origin of the sampled lumber. Further, our Terminal Warehouse tree-ring chronology (1512–1891 C.E.) correlated strongly with existing tree-ring chronologies from western/central Georgia and eastern Alabama, indicating that the timbers were extracted from this region of the southeastern United States. The provenancing and dating of the Terminal Warehouse timbers underscores the important role that southern pines played in the expansion and development of New York City during the Gilded Age.
Imperial building projects at Rome: c. 31 BC - AD 138
Creators: name: Apted, I
Publisher: name: University Of Tasmania
Year: 2023

description: This thesis examines the building projects undertaken under the auspices of the emperors within the limits of the city of Rome, from the beginning of the Principate under Augustus and then on through the following principes until the death of Hadrian in A. D. 138. The thesis focuses upon a particular aspect of these imperial building projects, namely the use of the urban environment as a primary means by which individual emperors could define and promote publicly their conception of the role of the institution that their building activities were helping to create. To achieve this aim, a large and diverse body of evidence is addressed, including archaeological, literary, inscriptional, and numismatic evidence. In addition the thesis examines a broad, though selective, contribution from the body of modern scholarship that has concerned itself with both this evidence, and with the broader thematic concerns to which the thesis is addressed. Following a brief introductory chapter the thesis examines and outlines the building programme of Octavian/ Augustus. The major thematic concerns are identified in order to reveal the behavioural and ideological template that the first princeps created. The thesis then proceeds to examine in chronological order the building activities of the succeeding principes. Against the backdrop of the Augustan example the individualised and idiosyncratic nature of the Julio-Claudian conception of the role of the princeps is revealed. Then follows the reaction of the Flavian dynasty, largely conservative in nature, though evolving over time to incorporate some of the concepts first experimented with under the later Julio-Claudians. An examination of the Trajanic building programme follows, and is revealed as having been conservative in its forms, though idiosyncratic in its aims. In the final chapter concerning Hadrian, the competing traits of all the previous principes are found to have been resolved and consolidated, to provide a new template for imperial building behaviours. The thesis concludes with the finding that the individual conceptions of the Principate by its incumbents is able to be traced in their building programmes. Moreover it is shown that through a process of actively incorporating or rejecting the examples of predecessors, an acceptable compromise between the ideal and the reality of the role and public profile of the Principate was finally achieved and found form in the urban environment of the city of Rome.
Optimally fast incremental Manhattan plane embedding and planar tight span construction
Creators: name: Eppstein, David
Publisher: name: Journal of Computational Geometry
Year: 2011

description: We describe a data structure, a rectangular complex, that can be used represent hyperconvex metric spaces that have the same topology (although not necessarily the same distance function) as subsets of the plane. We show how to use this data structure to construct the tight span of a metric space given as an n×n distance matrix, when the tight span is homeomorphic to a subset of the plane, in time O(n2), and to add a single point to a planar tight span in timeO(n). As an application of this construction, we show how to test whether a given ﬁnite metric space embeds isometrically into the Manhattan plane in time O(n2), and add a single point to the space and re-test whether it has such an embedding in time O(n).
description: Journal of Computational Geometry, Vol 2, No 1 (2011)
Five centuries of Upper Indus River flow from tree rings
Creators: Cook, Edward R.
Palmer, Jonathan G.
Ahmed, Moinuddin
Woodhouse, Connie A.
Fenwick, Pavla
Zafar, Muhammad Usama
Wahab, Muhammad
Khan, Nasrullah
Publisher: name: Columbia University
Year: 2013
Subjects: Climatic changes
Water resources development--Management
Hydrology

description: Water wars are a prospect in coming years as nations struggle with the effects of climate change, growing water demand, and declining resources. The Indus River supplies water to the world’s largest contiguous irrigation system generating 90% of the food production in Pakistan as well as 13 gigawatts of hydroelectricity. Because any gap between water supply and demand has major and far-reaching ramifications, an understanding of natural flow variability is vital – especially when only 47 years of instrumental record is available. A network of tree-ring sites from the Upper Indus Basin (UIB) was used to reconstruct river discharge levels covering the period AD 1452–2008. Novel methods tree-ring detrending based on the ‘signal free’ method and estimation of reconstruction uncertainty based on the ‘maximum entropy bootstrap’ are used. This 557-year record displays strong inter-decadal fluctuations that could not have been deduced from the short gauged record. Recent discharge levels are high but not statistically unprecedented and are likely to be associated with increased meltwater from unusually heavy prior winter snowfall. A period of prolonged below-average discharge is indicated during AD 1572–1683. This unprecedented low-flow period may have been a time of persistently below-average winter snowfall and provides a warning for future water resource planning. Our reconstruction thus helps fill the hydrological information vacuum for modeling the Hindu Kush–Karakoram–Himalayan region and is useful for planning future development of UIB water resources in an effort to close Pakistan’s “water gap”. Finally, the river discharge reconstruction provides the basis for comparing past, present, and future hydrologic changes, which will be crucial for detection and attribution of hydroclimate change in the Upper Indus Basin.
Investigating the Dual Processes Underlying Human Recognition Memory
Creators: name: Zhu, Wenying
Publisher: name: California Institute of Technology
Year: 2024
Subjects: Human Recognition Memory
Computation and Neural Systems

description: This thesis examines two aspects of human recognition memory by using two separate behavioral paradigms. Given the dual process hypothesis of recognition memory, the first chapter investigates the correlation between encoding and retrieval of recognition and source memory for images by using a cued retrieval paradigm. Participants were shown images in a particular judgment task (source context) and later asked to retrieve them in a cued retrieval task.  Recording from the human brain, I found separate cell populations to be responsive to the source context during the encoding and recognition stages of the task, suggesting a lack of single-cell level reactivation during source retrieval. In the second chapter, I examined how recognition memory signals change over time using repeated longitudinal behavioral testing in an fMRI study. Through repetitive presentation and memory tests over a period of three months, face stimuli were introduced to three participants. The behavioral outcome of the task showed that as frequency of exposure to specific faces increases, the memory performance and judged confidence increases correspondingly, supporting the hypothesis of a continuous familiarity signal.
Ten tene temas
Creators: name: SERİN, Ünzüle
Publisher: name: Zenodo
Year: 2019

description: Ünzüle SERİN, Nuran OYMA, Melike Nur HOŞ ve Ayşenur YALÇIN'IN ortak yapmış olduğu bu çalışmada İstanbul Medipol Üniversitesi Ebelik öğrencileri arasındaki ten tene temas hakkındaki bilgi düzeyi ölçme anketi sonucunda ulaşılan veriler yer almaktadır.
Continental-Scale Temperature Variability during the Past Two Millennia: Supplementary Information
Creators: Ahmed, Moinuddin
Anchukaitis, Kevin
Buckley, Brendan M.
Braida, Martina
Borgaonkar, Hemant P.
Asrat, Asfawossen
Cook, Edward R.
Büntgen, Ulf
Chase, Brian M.
Christie, Duncan A.
Curran, Mark A. J.
Diaz, Henry F.
Esper, Jan
Fan, Ze-Xin
Gaire, Narayan P.
Ge, Quansheng
Gergis, Joëlle
González-Rouco, Jesús Fidel
Goosse, Hugues
Grab, Stefan W.
Graham, Nicholas
Graham, Rochelle
Grosjean, Martin
Hanhijärvi, Sami T.
Kaufman, Darrell S.
Kiefer, Thorsten
Kimura, Katsuhiko
Korhola, Atte A.
Krusic, Paul J.
Lara, Antonio
Lézine, Anne-Marie
Ljungqvist, Fredrik C.
Lorrey, Andrew M.
Luterbacher, Jürg
Masson-Delmotte, Valérie
Viau, Andre E.
McCarroll, Danny
McConnell, Joseph R.
McKay, Nicholas P.
Morales, Mariano S.
Moy, Andrew D.
Mulvaney, Robert
Mundo, Ignacio A.
Nakatsuka, Takeshi
Nash, David J.
Neukom, Raphael
Nicholson, Sharon E.
Oerter, Hans
Palmer, Jonathan G.
Phipps, Steven J.
Prieto, Maria R.
Rivera, Andres
Sano, Masaki
Severi, Mirko
Shanahan, Timothy M.
Shao, Xuemei
Shi, Feng
Sigl, Michael
Smerdon, Jason E.
Solomina, Olga N.
Steig, Eric J.
Stenni, Barbara
Thamban, Meloth
Trouet, Valerie
Turney, Chris S. M.
Umer, Mohammed
van Ommen, Tas
Verschuren, Dirk
Villalba, Ricardo
Vinther, Bo M.
von Gunten, Lucien
Wagner, Sebastian
Wahl, Eugene R.
Wanner, Heinz
Werner, Johannes P.
White, James W. C.
Yasue, Koh
Zorita, Eduardo
Publisher: name: Columbia University
Year: 2013
Subjects: Earth temperature
Atmosphere
Paleoclimatology
Climatic changes

description: Past global climate changes had strong regional expression. To elucidate their spatio-temporal pattern, we reconstructed past temperatures for seven continental-scale regions during the past one to two millennia. The most coherent feature in nearly all of the regional temperature reconstructions is a long-term cooling trend, which ended late in the nineteenth century. At multi-decadal to centennial scales, temperature variability shows distinctly different regional patterns, with more similarity within each hemisphere than between them. There were no globally synchronous multi-decadal warm or cold intervals that define a worldwide Medieval Warm Period or Little Ice Age, but all reconstructions show generally cold conditions between ad 1580 and 1880, punctuated in some regions by warm decades during the eighteenth century. The transition to these colder conditions occurred earlier in the Arctic, Europe and Asia than in North America or the Southern Hemisphere regions. Recent warming reversed the long-term cooling; during the period ad 1971–2000, the area-weighted average reconstructed temperature was higher than any other time in nearly 1,400 years.
European and Mediterranean hydroclimate responses to tropical volcanic forcing over the last millennium
Creators: Rao, Mukund Palat
Cook, Benjamin I.
Cook, Edward R.
D'Arrigo, Rosanne Dorothy
Krusic, Paul J.
Anchukaitis, Kevin
LeGrande, Allegra N.
Buckley, Brendan M.
Davi, Nicole K.
Leland, Caroline Wogan
Griffin, Kevin L.
Publisher: name: Columbia University
Year: 2017
Subjects: Volcanic eruptions
Hydrology

description: Volcanic eruptions have global climate impacts, but their effect on the hydrologic cycle is poorly understood. We use a modified version of superposed epoch analysis, an eruption year list collated from multiple data sets, and seasonal paleoclimate reconstructions (soil moisture, precipitation, geopotential heights, and temperature) to investigate volcanic forcing of spring and summer hydroclimate over Europe and the Mediterranean over the last millennium. In the western Mediterranean, wet conditions occur in the eruption year and the following 3 years. Conversely, northwestern Europe and the British Isles experience dry conditions in response to volcanic eruptions, with the largest moisture deficits in posteruption years 2 and 3. The precipitation response occurs primarily in late spring and early summer (April–July), a pattern that strongly resembles the negative phase of the East Atlantic Pattern. Modulated by this mode of climate variability, eruptions force significant, widespread, and heterogeneous hydroclimate responses across Europe and the Mediterranean.
$d$-representability of simplicial complexes of fixed dimension
Creators: name: Tancer, Martin
Publisher: name: Journal of Computational Geometry
Year: 2011

description: Let K be a simplicial complex with vertex set V = v1,…,vn. The complex K is d-representable if there is a collection {C1,…,Cn} of convex sets in Rd such that a subcollection {Ci1,…,Cij} has a nonempty intersection if and only if {vi1,…,vij} is a face of K. In 1967 Wegner proved that every simplicial complex of dimension d is (2d+1)-representable. He also conjectured that his bound is the best possible, i.e., that there are d-dimensional simplicial complexes which are not 2d-representable. However, he was not able to prove his conjecture. We prove that his suggestion was indeed right. Thus we add another piece to the puzzle of intersection patterns of convex sets in Euclidean space.
description: Journal of Computational Geometry, Vol 2, No 1 (2011)
On thermodynamics of N=6 superconformal Chern-Simons theory
Creators: name: Smedbäck, Mikael
Publisher: name: arXiv
Year: 2010
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We study thermodynamics of N=6 superconformal Chern-Simons theory by computing quantum corrections to the free energy. We find that in weakly coupled ABJM theory on R(2) x S(1), the leading correction is non-analytic in the 't Hooft coupling lambda, and is approximately of order lambda^2 log(lambda)^3. The free energy is expressed in terms of the scalar thermal mass m, which is generated by screening effects. We show that this mass vanishes to 1-loop order. We then go on to 2-loop order where we find a finite and positive mass squared m^2. We discuss differences in the calculation between Coulomb and Lorentz gauge. Our results indicate that the free energy is a monotonic function in lambda which interpolates smoothly to the N^(3/2) behaviour at strong coupling.
description: 29 pages. v2: references added. v3: minor changes, references added, published version
Modelling magnetars' high energy emission through Resonant Cyclotron Scattering
Creators: name: Gotz, D.
name: Rea, N.
name: Zane, S.
name: Turolla, R.
name: Lyutikov, M.
Publisher: name: arXiv
Year: 2009
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: We present a systematic fit of a model of resonant cyclotron scattering (RCS) to the X and soft gamma-ray data of four magnetars, including anomalous X-ray pulsars, and soft gamma repeaters. In this scenario, non-thermal magnetar spectra in the soft X-rays result from resonant cyclotron scattering of the thermal surface emission by hot magnetospheric plasma. We find that this model can successfully account for the soft X-ray emission of magnetars, while an additional component is still required to model the hard X-ray persistent magnetar emission recently discovered by INTEGRAL. The latter is an important component in terms of magnetars' luminosity, and cannot be neglected when modelling the soft X-ray part of the spectrum.
description: 12 pages, 4 figures, presented at the 7th INTEGRAL Workshop "An INTEGRAL View of Compact Objects", 8-11 September 2008, to be published by PoS
HIV-1 Gag specifically restricts PI(4,5)P2 and cholesterol mobility in living cells creating a nanodomain platform for virus assembly
Creators: name: Favard, C.
name: Chojnacki, Jakub
name: Merida, P.
name: Yandrapalli, N.
name: Mak, J.
name: Eggeling, Christian
name: Muriaux, D.
Publisher: name: Washington D.C. : AAAS
Year: 2019
Subjects: subject: HIV-1
subject: cholesterol
subject: assembly
subject: 610

description: HIV-1 Gag protein assembles at the plasma membrane of infected cells for viral particle formation. Gag targets lipids, mainly PI(4,5)P2, at the inner leaflet of this membrane. Here, we address the question whether Gag is able to trap specifically PI(4,5)P2 or other lipids during HIV-1 assembly in the host CD4+ T lymphocytes. Lipid dynamics within and away from HIV-1 assembly sites were determined using super-resolution microscopy coupled with scanning fluorescence correlation spectroscopy in living cells. Analysis of HIV-1–infected cells revealed that, upon assembly, HIV-1 is able to specifically trap PI(4,5)P2 and cholesterol, but not phosphatidylethanolamine or sphingomyelin. Furthermore, our data showed that Gag is the main driving force to restrict the mobility of PI(4,5)P2 and cholesterol at the cell plasma membrane. This is the first direct evidence highlighting that HIV-1 creates its own specific lipid environment by selectively recruiting PI(4,5)P2 and cholesterol as a membrane nanoplatform for virus assembly.
Spectra of PT-symmetric Hamiltonians on Tobogganic Contours
Creators: name: Bíla, Hynek
Publisher: name: arXiv
Year: 2009
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: A non-standard generalisation of the Bender potentials $x^2(\ii x^\ve)$ is suggested. The spectra are obtained numerically and some of their particular properties are discussed.
description: 9 pages
A comparative analysis of statistical hadron production
Creators: name: Becattini, F.
name: Castorina, P.
name: Milov, A.
name: Satz, H.
Publisher: name: arXiv
Year: 2009
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: We perform a systematic comparison of the statistical model parametrization of hadron abundances measured in high energy pp, AA and e+e- collisions. The basic aim of the study is to test if the quality of the description depends on the nature of the collision process. In particular, we want to see if nuclear collisions, with multiple initial interactions, lead to "more thermal" average multiplicities than elementary pp collisions or e+e- annihilation. Such a comparison is meaningful only if it is based on data for the same or similar hadronic species and if the analyzed data has quantitatively similar errors. When these requirements are maintained, the quality of the statistical model description is found to be the same for the different initial collision configurations.
description: 14 pages, 2 figures. Revised version accepted for publication in Eur. Phys. J. C
Hydrometeorological Reconstructions for Northeastern Mongolia Derived from Tree Rings: 1651–1995
Creators: Pederson, Neil
Jacoby, Gordon
D'Arrigo, Rosanne Dorothy
Cook, Edward R.
Buckley, Brendan M.
Dugarjav, Chultemiin
Mijiddorj, R.
Publisher: name: Columbia University
Year: 2000
Subjects: Meteorology
Hydrology
Paleoclimatology

description: Reconstructions of annual (prior August–current July) precipitation and streamflow, 345 yr in length (1651–1995), are presented for northeastern Mongolia based on tree-ring width data. These precipitation and streamflow reconstructions account for 54% and 48% of the respective variance in instrumental data over the past 50 years. Variations in instrumental precipitation and streamflow are within the range of those reconstructed over the length of tree-ring records. However, there appear to be more frequent extended wet periods during the twentieth century. Multitaper spectral analysis revealed statistically significant peaks at 10.8 and 12.8 yr for the precipitation reconstruction, and at 12.8 and 20.3–23.8 yr for the streamflow reconstruction. Similarly, singular spectrum analysis identified spectral modes of variation at 12 and 21 yr for both series. These spectra resemble those found for tree-ring-based precipitation reconstructions in central China as well as the western United States, and may reflect solar influences on the climate of Mongolia.
Shot noise in Graphene with long range Coulomb interaction and the local Fermi distribution
Creators: name: Golub, Anatoly
name: Horovitz, Baruch
Publisher: name: arXiv
Year: 2009
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Other Condensed Matter (cond-mat.other)
subject: FOS: Physical sciences

description: We calculate the shot noise power in ballistic graphene using the kinetic equation approach based on the Keldysh technique. We find that the local energy distribution function obeys Poisson's equation, indicating a mapping into a diffusive metal system. We derive the conductance and noise including the long range Coulomb interaction to first order. We find that the shot noise increases due to interaction, leading to a frequency dependence. Furthermore, we find that the Fano factor at degeneracy is 1/3, the same as without the Coulomb interaction.
description: Extended version. 6 pages, 2 figure
Internal ocean-atmosphere variability drives megadroughts in Western North America
Creators: Coats, Sloan John
Smerdon, Jason E.
Seager, Richard
Cook, Benjamin I.
Cook, Edward R.
Anchukaitis, Kevin
Publisher: name: Columbia University
Year: 2016
Subjects: subject: Climatic changes--Risk assessment
subject: Hydrologic models
subject: Drought forecasting
subject: Droughts
subject: Climatic changes
subject: Geophysics
subject: FOS: Earth and related environmental sciences
subject: Paleoclimatology

description: Multidecadal droughts that occurred during the Medieval Climate Anomaly represent an important target for validating the ability of climate models to adequately characterize drought risk over the near-term future. A prominent hypothesis is that these megadroughts were driven by a centuries-long radiatively forced shift in the mean state of the tropical Pacific Ocean. Here we use a novel combination of spatiotemporal tree ring reconstructions of Northern Hemisphere hydroclimate to infer the atmosphere-ocean dynamics that coincide with megadroughts over the American West and find that these features are consistently associated with 10–30 year periods of frequent cold El Niño–Southern Oscillation conditions and not a centuries-long shift in the mean of the tropical Pacific Ocean. These results suggest an important role for internal variability in driving past megadroughts. State-of-the-art climate models from the Coupled Model Intercomparison Project Phase 5, however, do not simulate a consistent association between megadroughts and internal variability of the tropical Pacific Ocean, with implications for our confidence in megadrought risk projections.
Stress Relaxation in Entangled Polymer Melts
Creators: name: Hou, Ji Xuan
name: Svaneborg, Carsten
name: Everaers, Ralf
name: Grest, Gary S.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: FOS: Physical sciences

description: We present an extensive set of simulation results for the stress relaxation in equilibrium and step-strained bead-spring polymer melts. The data allow us to explore the chain dynamics and the shear relaxation modulus, $G(t)$, into the plateau regime for chains with $Z=40$ entanglements and into the terminal relaxation regime for $Z=10$. Using the known (Rouse) mobility of unentangled chains and the melt entanglement length determined via the primitive path analysis of the microscopic topological state of our systems, we have performed parameter -free tests of several different tube models. We find excellent agreement for the Likhtman-McLeish theory using the double reptation approximation for constraint release, if we remove the contribution of high-frequency modes to contour length fluctuations of the primitive chain.
description: 5 pages, 3 figures
Population Dynamics of a Spin-1 Bose Gas Above the Bose-Einstein Transition Temperature
Creators: name: Endo, Yuki
name: Nikuni, Tetsuro
Publisher: name: arXiv
Year: 2009
Subjects: subject: Other Condensed Matter (cond-mat.other)
subject: FOS: Physical sciences

description: We study population dynamics of a trapped spin-1 Bose gas above the Bose-Einstein transition temperature. Starting from the semiclassical kinetic equation for a spin-1 gas, we derive a coupled rate equations for the populations of internal states. Solving the rate equations, we discuss the dynamical evolution of spin populations. We also estimate the characteristic timescale in which the system reaches equilibrium. Finally, we briefly discuss how the presence of the condensate will affect the population dynamics.
description: 6pages,1figure
Colloquium: Statistical mechanics of money, wealth, and income
Creators: name: Yakovenko, Victor M.
name: Rosser, J. Barkley
Publisher: name: arXiv
Year: 2009
Subjects: subject: Statistical Finance (q-fin.ST)
subject: FOS: Economics and business

description: This Colloquium reviews statistical models for money, wealth, and income distributions developed in the econophysics literature since the late 1990s. By analogy with the Boltzmann-Gibbs distribution of energy in physics, it is shown that the probability distribution of money is exponential for certain classes of models with interacting economic agents. Alternative scenarios are also reviewed. Data analysis of the empirical distributions of wealth and income reveals a two-class distribution. The majority of the population belongs to the lower class, characterized by the exponential ("thermal") distribution, whereas a small fraction of the population in the upper class is characterized by the power-law ("superthermal") distribution. The lower part is very stable, stationary in time, whereas the upper part is highly dynamical and out of equilibrium.
description: 24 pages, 13 figures; v.2 - minor stylistic changes and updates of references corresponding to the published version
Disk-outflow coupling: Energetics around spinning black holes
Creators: name: Bhattacharya, Debbijoy
name: Ghosh, Shubhrangshu
name: Mukhopadhyay, Banibrata
Publisher: name: arXiv
Year: 2009
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: The mechanism by which outflows and plausible jets are driven from black hole systems, still remains observationally elusive. Notwithstanding, several observational evidences and deeper theoretical insights reveal that accretion and outflow/jet are strongly correlated. We model an advective disk-outflow coupled dynamics, incorporating explicitly the vertical flux. Inter-connecting dynamics of outflow and accretion essentially upholds the conservation laws. We investigate the properties of the disk-outflow surface and its strong dependence on the rotation parameter of the black hole. The energetics of the disk-outflow strongly depend on the mass, accretion rate and spin of the black holes. The model clearly shows that the outflow power extracted from the disk increases strongly with the spin of the black hole, inferring that the power of the observed astrophysical jets has a proportional correspondence with the spin of the central object. In case of blazars (BL Lacs and Flat Spectrum Radio Quasars), most of their emission are believed to be originated from their jets. It is observed that BL Lacs are relatively low luminous than Flat Spectrum Radio Quasars (FSRQs). The luminosity might be linked to the power of the jet, which in turn reflects that the nuclear regions of the BL Lac objects have a relatively low spinning black hole compared to that in the case of FSRQ. If the extreme gravity is the source to power strong outflows and jets, then the spin of the black hole, perhaps, might be the fundamental parameter to account for the observed astrophysical processes in an accretion powered system.
description: 10 pages including 7 figures; final version to appear in ApJ
Nativity, Neighborhoods, and Body Composition in the Sacramento Area Latino Study on Aging
Creators: name: Aiello, A.E.
name: Durazo, E.M.
name: Dang, K.
name: Torres, J.M.
name: Haan, M.N.
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2020

description: BACKGROUND AND OBJECTIVES: Globally, obesity influences the risk of many major chronic diseases. Our study examines the association between individual nativity and neighborhood level concentration of immigrants with 10-year changes in weight, body mass index (BMI), and waist circumference (WC) among older Latinos. RESEARCH DESIGN AND METHODS: The Sacramento Area Latino Study on Aging (SALSA) is a population-based prospective study of community-dwelling older adults of Mexican origin (baseline ages 58-101 years). The primary outcome was repeated measures of weight over a 10-year period for 1,628 respondents. Nativity was defined by participants' reported place of birth (US-born or Latin American foreign born). Neighborhood immigrant concentration was measured as the percentage of foreign born at census tract level (2000 US Census). We used linear mixed models with repeated measures of weight, height, BMI, and WC as dependent variables (level 1), clustered within individuals (level 2) and neighborhood migrant concentration (level 3). RESULTS: Foreign born (FB) respondents had lower baseline weight than the US-born (mean, 160 vs. 171 lbs, p < .0001). Over time, weight differences between the FB and the US-born decreased by 1.7 lbs/5 years as US-born weight decreased more rapidly. We observed a significant interaction between individual nativity and neighborhood immigrant concentration (p = .012). We found similar patterns for BMI, but did not find statistically significant differences in WC trajectories. DISCUSSION AND IMPLICATIONS: Our study observed significant differences by foreign born vs. US nativity in baseline weight/BMI and in their trajectories over time. Additionally, we found weight/BMI differences in neighborhood immigrant concentration for the FB, but not for the US-born.
Introduction to the Symposium: Causal Inference and Public Health
Creators: name: Green, L.W.
name: Aiello, A.E.
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2019

description: Assessing the extent to which public health research findings can be causally interpreted continues to be a critical endeavor. In this symposium, we invited several researchers to review issues related to causal inference in social epidemiology and environmental science and to discuss the importance of external validity in public health. Together, this set of articles provides an integral overview of the strengths and limitations of applying causal inference frameworks and related approaches to a variety of public health problems, for both internal and external validity.
Links between Indo-Pacific climate variability and drought in the Monsoon Asia Drought Atlas
Creators: Ummenhofer, Caroline C.
D'Arrigo, Rosanne Dorothy
Anchukaitis, Kevin
Buckley, Brendan M.
Cook, Edward R.
Publisher: name: Columbia University
Year: 2012
Subjects: Climatic changes
Droughts
Climatology

description: Drought patterns across monsoon and temperate Asia over the period 1877–2005 are linked to Indo-Pacific climate variability associated with the El Niño-Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD). Using the Monsoon Asia Drought Atlas (MADA) composed of a high-resolution network of hydroclimatically sensitive tree-ring records with a focus on the June–August months, spatial drought patterns during El Niño and IOD events are assessed as to their agreement with an instrumental drought index and consistency in the drought response amongst ENSO/IOD events. Spatial characteristics in drought patterns are related to regional climate anomalies over the Indo-Pacific basin, using reanalysis products, including changes in the Asian monsoon systems, zonal Walker circulation, moisture fluxes, and precipitation. A weakening of the monsoon circulation over the Indian subcontinent and Southeast Asia during El Niño events, along with anomalous subsidence over monsoon Asia and reduced moisture flux, is reflected in anomalous drought conditions over India, Southeast Asia and Indonesia. When an IOD event co-occurs with an El Niño, severe drought conditions identified in the MADA for Southeast Asia, Indonesia, eastern China and central Asia are associated with a weakened South Asian monsoon, reduced moisture flux over China, and anomalous divergent flow and subsidence over Indonesia. Insights into the relative influences of Pacific and Indian Ocean variability for Asian monsoon climate on interannual to decadal and longer timescales, as recorded in the MADA, provide a useful tool for assessing long-term changes in the characteristics of Asian monsoon droughts in the context of Indo-Pacific climate variability.