cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Cortical thickness in presymptomatic GRN and C9ORF72 mutation carriers
Creators: name: Dowds, Emma Frances
Publisher: name: University of British Columbia
Year: 2014

description: Objective: This thesis aimed to investigate cortical thickness in presymptomatic GRN and C9ORF72 mutation carriers prior to the onset of frontotemporal dementia (FTD). Methods: Subjects were recruited from 16 families with a family history of FTD caused by GRN or C9ORF72 mutations. The C9ORF72 group consisted of 8 mutation carriers (age 50.25 ± 6.90 years), 11 non-carrier family member controls (age 52.82 ± 17.15 years), and 3 affected carriers (age 55.00 ± 1.00 years). The GRN group consisted of 6 mutation carriers (age 53.33 ± 9.67 years) and 9 non-carrier family member controls (age 52.11 ± 8.82). Between group differences in cortical thickness were assessed using a surface based vertex-by-vertex model correcting for age, sex, MMSE and years to mean age of family onset. Significant clusters are reported at 10mm, 15mm and 20mm of smoothing and those identified at all three, two consecutive or one smoothing level are reported with strong, moderate and weak confidence, respectively. Results: Compared to non-carrier control family members, the C9ORF72 mutation carriers exhibited no difference in cognitive domain scores, but presented with strong to moderate asymmetrical patterns of thinning in the right temporoinsular and left mediofrontal and temporal regions. Compared to non-carrier controls, the GRN mutation carriers exhibited decreased performance on domains of working memory (p = 0.02) and executive function (p = 0.01), with a trend towards reduced language (p = 0.06) and visuospatial (p = 0.08) domains, but did not exhibit any difference in cortical thickness when compared to the non-carrier control family members. Conclusions: With the use of genetic screening and neuroimaging analyses this thesis demonstrated that grey matter atrophy occurs prior to cognitive decline in C9ORF72 mutation carriers, while GRN carriers exhibit subtle changes in cognitive domains prior to cortical grey matter atrophy. These findings could prove to be highly valuable as they suggest that the mechanism of disease progression between the two mutations may differ. As such, each mutation may require specific neuroimaging methods to track morphological changes prior to cognitive decline and clinical onset.
The Galactic Plane at faint X-ray fluxes - I: Properties and characteristics of the X-ray source population
Creators: name: Warwick, R. S.
name: Perez-Ramirez, D.
name: Byckling, K.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We investigate the serendipitous X-ray source population revealed in XMM-Newton observations targeted in the Galactic Plane within the region 31510^{32} erg/s, whereas some will be extragalactic interlopers. >90% of the soft sources have potential NIR (2MASS and/or UKIDSS) counterparts inside their error circles, consistent with the dominant soft X-ray source population being relatively nearby coronally-active stars. These stellar counterparts are generally brighter than J=16, a brightness cutoff which corresponds to the saturation of the X-ray coronal emission at L_X=10^{-3} L_{bol}. In contrast, the success rate in finding likely IR counterparts to the hard X-ray sample is no more than ~15% down to J=16 and ~25% down to J=20, set against a rapidly rising chance coincidence rate. The make-up of the hard X-ray source population, in terms of the known classes of accreting and non-accreting systems, remains uncertain.
description: 17 pages, 17 figures, accepted for publication in MNRAS
Statistical analysis of complex systems with nonclassical invariant measures
Creators: name: Fratalocchi, A.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Pattern Formation and Solitons (nlin.PS)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: I investigate the problem of finding a statistical description of a complex many-body system whose invariant measure cannot be constructed stemming from classical thermodynamics ensembles. By taking solitons as a reference system and by employing a general formalism based on the Ablowitz-Kaup-Newell-Segur scheme, I demonstrate how to build an invariant measure and, within a one dimensional phase space, how to develop a suitable thermodynamics. A detailed example is provided with a universal model of wave propagation, with reference to a transparent potential sustaining gray solitons. The system shows a rich thermodynamic scenario, with a free energy landscape supporting phase transitions and controllable emergent properties. I finally discuss the origin such behavior, trying to identify common denominators in the area of complex dynamics.
description: 9 pages, 4 figures
ටෙලිනාට්‍යයන්හි 'මීලග කොටස' යන රූපරාමු පෙළෙන් ප්‍රේක්‍ෂාවට සිදුවන බලපෑම.
Creators: name: Gayan Rajapaksha
Publisher: name: Zenodo
Year: 2019

description: සොප් ඔපෙරාවෙන් ආරම්භවන ටෙලිනාට්‍ය කලාව, විවිධ වූ සමාජ හා සංස්කෘතික අනන්‍යතාවයකින් යුක්තව
 නිර්මාණය විය. දිමුතු මුතු සිට විවිධ වූ ෂානරයන්හි නිර්මාණයන් සහිතව ලාංකේය ටෙලිනාට්‍ය බිහිවන්නට විය.
 ටෙලිනාට්‍ය සිය මුඛාර්ථය වූ කතාවක් කීමයන සංදර්භයෙන් විතැන්ව සමාජ දේශපාලනික මැදිහත්වීම සහිතව ද,
 නිර්මාණය විය. එහිදී ප්‍රේක්ෂකයා ටෙලිනාට්‍ය කෙරෙහි රදවාගෙන සිටීම සඳහා විවිධ වූ උපක්‍රම භාවිතකරනු ලැබීය.
 අනුව දශකයේ මැදබාගයේ දී, ටෙලිනාට්‍ය විකාශයවීමෙන් අනතුරුව, මීලග කතාංගයේ දර්ශන කිහිපයක් විකාශය
 කිරීම සිදුකරනු ලැබීය. වර්තමානයවන විට එය සෑම ටෙලිනාට්‍යක් සඳහාම අනිවාර්ය අංගයක්වී හමාරය.
 ටෙලිනාට්‍යක තිරපිටපතේ රේඛිය ගමන්මග වෙනුවට උච්චාවචනයවන කුතුහලයක් සහිතව කතාව
 ඉදිරිපත්කරනු ලබයි. මෙහිදී ප්‍රේක්ෂකයා ටෙලිනාට්‍යයේ රඳවාගෙන සිටීමටනම් මොහොතින් මොහෙත කුතුහලය
 ඉදිරියට රැගෙන යායුතුය. එක් කතාංගයක අවසානයේ අනෙක් කතාංගයේ බැලීම සඳහා පෙලඹුමක් ඇති කිරීම සඳහා
 අධ්‍යක්ෂකවරයා කුතුහලය පෙළඹුම්කාරකයක් ලෙස භාවිතකළ යුතුය. ටෙලි නිර්මාණයේ ගුණත්මකභාවය අතික්‍රමනය
 කරමින් නරඹන ප්‍රේක්ෂක සංඛ්‍යාව සදහා කුතුහලය යන සාධකය ඍජුව බලපානු ලබයි.
 ලංකාවේ භාවිත ටෙලිනාට්‍ය මීලග කොටසින් දර්ශන කොටස ප්‍රේක්ෂක කුතුහලය තුළින් ටෙලිනාට්‍ය නැරඹීමේ
 පෙලඹුම්කාරකයන් ලෙස භාවිතා කිරීම අල්පය. ටෙලිනාට්‍යයේ කිසියම් දර්ශන කීපයක් දැක්වීමට එහා ගිය රූපමාධ්‍ය
 සතු ශඛ්‍යතා භාවිතා කරමින් ප්‍රේක්ෂක ආකාර්ශනයක් ඇති කිරීමට වර්තමාන ටෙලිනාට්‍ය අවසන් දර්ශන භාවිතා
 නොකරනු ලබයි.
N-body Simulations for Extended Quintessence Models
Creators: name: Li, Baojiu
name: Mota, David F.
name: Barrow, John D.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We introduce the N-body simulation technique to follow structure formation in linear and nonlinear regimes for the extended quintessence models (scalar-tensor theories in which the scalar field has a self-interaction potential and behaves as dark energy), and apply it to a class of models specified by an inverse power-law potential and a non-minimal coupling. Our full solution of the scalar field perturbation confirms that, when the potential is not too nonlinear, the effects of the scalar field could be accurately approximated as a modification of background expansion rate plus a rescaling of the effective gravitational constant relevant for structure growth. For the models we consider, these have opposite effects, leading to a weak net effect in the linear perturbation regime. However, on the nonlinear scales the modified expansion rate dominates and could produce interesting signatures in the matter power spectrum and mass function, which might be used to improve the constraints on the models from cosmological data. We show that the density profiles of the dark matter halos are well described by the Navarro-Frenk-White formula, although the scalar field could change the concentration. We also derive an analytic formula for the scalar field perturbation inside halos assuming NFW density profile and sphericity, which agrees well with numerical results if the parameter is appropriately tuned. The results suggest that for the models considered, the spatial variation of the scalar field (and thus the locally measured gravitational constant) is very weak, and so local experiments could see the background variation of gravitational constant.
description: 21 pages, 9 figures, 1 table
The Lennard-Jones Potential Minimization Problem for Prion AGAAAAGA Amyloid Fibril Molecular Modeling
Creators: name: Zhang, Jiapu
Publisher: name: arXiv
Year: 2011
Subjects: subject: Mathematical Physics (math-ph)
subject: Optimization and Control (math.OC)
subject: Biological Physics (physics.bio-ph)
subject: FOS: Physical sciences
subject: FOS: Mathematics

description: The simplified Lennard-Jones (LJ) potential minimization problem is minimize f(x)=4\sum_{i=1}^N \sum_{j=1,j
Carbon Neutral Lifestyles and NDCs: Advice and Policy Perspectives
Creators: name: Cavalli, Laura
name: Boeri, Chiara
Publisher: name: Unknown
Year: 2023
Subjects: subject: International Development
subject: Public Economics
subject: Resource /Energy Economics and Policy
subject: public economics
subject: government
subject: environmental
subject: regional household behavior

description: Climate change is one of the most important challenges for the present generation, which is living in decades characterized by a drastic increase in greenhouse gas emissions, especially in the most developed countries: not only the production realities – for which policies already largely provide for mitigation measures – contribute to emissions; but also, individual citizens to whom only a small part of the envisaged measures are addressed. Among the policies in which the demand side is little addressed are the Nationally Determined Contributions, which embody the efforts of each country to reduce national emissions and adapt to the impacts of climate change, as stated in the Paris Agreement signed in 2015 between the Member States of the United Nations Framework Convention on Climate Change (UNFCCC). Integrating advice on carbon neutral lifestyles in NDCs and long-term strategies could have positive implications in both social, economic, and environmental terms, paving the way for more holistic and inclusive policies, fundamental elements to pursue a development that is sustainable in the short and above all in the medium-long term. Taking this into account, the present work, which forms an integral part of the studies of WP 7 within the Horizon 2020 Project CAMPAIGNers- Citizens Acting on Mitigation Pathways through Active Implementation of a Goal-setting Network1, aims to understand what the consequences deriving from the inclusion of carbon neutral lifestyle advice in the Nationally Determined Contributions and national climate strategies would be, and to operationally implement practical examples and ways to include behavioural aspects of the carbon neutral lifestyle in the sectors studied, based on national data and statistics from the countries participating in the Project2. The innovative aspect of the Project lies in integrating the quantitative aspects deriving from the scientific evidence of official statistics with qualitative aspects generated by the collaboration between partners and stakeholders, in the form of surveys and focus groups: in this way it is possible to effectively overlap the spheres of economic and environmental analysis with that of policy making, providing a tool capable of directing strategies and international agendas.
Perturbations of eigenvalues embedded at threshold: one, two and three dimensional solvable models
Creators: name: Cacciapuoti, Claudio
name: Carlone, Raffaele
name: Figari, Rodolfo
Publisher: name: arXiv
Year: 2010
Subjects: subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences
subject: 81Q10, 30B40, 35B34

description: We examine perturbations of eigenvalues and resonances for a class of multi-channel quantum mechanical model-Hamiltonians describing a particle interacting with a localized spin in dimension $d=1,2,3$. We consider unperturbed Hamiltonians showing eigenvalues and resonances at the threshold of the continuous spectrum and we analyze the effect of various type of perturbations on the spectral singularities. We provide algorithms to obtain convergent series expansions for the coordinates of the singularities.
description: 20 pages
Universal amplitude in density-force relations for polymer chains in confined geometries: Massive field theory approach
Creators: name: Usatenko, Z.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: FOS: Physical sciences

description: The universal density-force relation is analyzed and the correspondent universal amplitude ratio $B_{real}$ is obtained using the massive field theory approach in fixed space dimensions d=3 up to one-loop order. The layer monomer density profiles of ideal chains and real polymer chains with excluded volume interaction in a good solvent between two parallel repulsive walls, one repulsive and one inert wall are obtained. Besides, taking into account the Derjaguin approximation the layer monomer density profiles for dilute polymer solution confined in semi-infinite space containing mesoscopic spherical particle of big radius are calculated. The last mentioned situation is analyzed for both cases when wall and particle are repulsive and for the mixed case of repulsive wall and inert particle. The obtained results are in good agreement with previous theoretical results and with the results of Monte Carlo simulations.
description: 11 pages, 3 figures
How habitual exercise can benefit Parkinson's disease
Creators: name: Murray, Danielle Kristin
Publisher: name: University of British Columbia
Year: 2014

description: Exercise can improve symptoms of Parkinson's disease (PD), including bradykinesia, balance, cognition and quality of life, but the therapeutic mechanisms of benefit are poorly understood. First, this thesis aimed to fill a gap in the literature through a systematic review on the effects of exercise on cognition in PD. This systematic review identified the benefits of exercise for cognition, but found studies seldom involved an intervention over 12 weeks, and few human studies investigated mechanisms of exercise in PD. Therefore, we next tested our novel research question: what are the effects of long-term regular (i.e., habitual) exercise on PD, and what may be the associated mechanisms of benefit for motor and non-motor symptoms? Our study compared 12 PD subjects allocated to one of two matched cohorts (n = 6 each), differing only in regular exercise levels. The primary outcome was dorsal and ventral striatal dopamine release in response to acute exercise (30 min cycling) measured using PET and displacement of [¹¹C]raclopride (RAC) binding potential (BP). The secondary outcomes were response to reward in the ventral striatum measured with BOLD percent signal change (PSC) using fMRI, as well as clinical measures of motor function, cognition, mood and apathy. We found habitual exercisers did not release more striatal dopamine in response to acute exercise. In contrast, we found that habitual exercisers had increased RAC BP in their less affected anterior putamen post-exercise. During the fMRI card task habitual exercisers had greater BOLD PSC compared to baseline and both cohorts had greater activation during the reward phase compared to the anticipation phase. In terms of clinical outcomes, habitual exercisers had greater aerobic capacity (VO₂ peak, confirming cohort allocation), as well as improved finger tapping, peg insertion, faster walking, less depression, more positive affect, and less apathy. In summary, habitual exercise does not affect dopamine release in response to acute exercise, but may impact striatal RAC binding as well as response to reward in the ventral striatum. There may be dopaminergic contributions to the motor and mood benefits from habitual exercise in PD, but this topic requires further study.
The High-Density Ionized Gas in the Central Parsec of the Galaxy
Creators: name: Zhao, Jun-Hui
name: Blundell, Ray
name: Moran, James M.
name: Downes, Dennis
name: Schuster, Karl F.
name: Marrone, Daniel P.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We report a study of the H30$α$ line emission at 1.3 mm from the region around Sgr A* made with the Submillimeter Array at a resolution of 2\arcsec\ over a field of 60\arcsec\ (2 parsec) and a velocity range of -360 to +345 \kms. This field encompasses most of the Galactic center's "minispiral". With an isothermal homogeneous HII model, we determined the physical conditions of the ionized gas at specific locations in the Northern and Eastern Arms from the H30$α$ line data along with Very Large Array data from the H92$α$ line at 3.6 cm and from the radio continuum emission at 1.3 cm. The typical electron density and kinetic temperature in the minispiral arms are 3-21$\times10^4$ cm$^{-3}$ and 5,000-13,000 K, respectively. The H30$α$ and H92$α$ line profiles are broadened due to the large velocity shear within and along the beam produced by dynamical motions in the strong gravitational field near Sgr A*. We constructed a 3D model of the minispiral using the orbital parameters derived under the assumptions that the gas flows are in Keplerian motion. The gas in the Eastern Arm appears to collide with the Northern Arm flow in the "Bar" region, which is located 0.1-0.2 parsec south of and behind Sgr A*. Finally, a total Lyman continuum flux of $3\times10^{50}$ photons s$^{-1}$ is inferred from the assumption that the gas is photoionized and the ionizing photons for the high-density gas in the minispiral arms are from external sources, which is equivalent to $\sim250$ O9-type zero-age-main-sequence stars.
description: 23 pages, including 8 figures, accepted for publication in the Astrophysical Journal
Systematic conservation planning in human-dominated landscapes : maximizing efficiency in biodiversity conservation via carbon sequestration and land management
Creators: name: Schuster, Richard
Publisher: name: University of British Columbia
Year: 2014

description: Investments in habitat and biodiversity conservation are critically needed given mounting effects of global climate change and unprecedented rates of ecological degradation and species extinction. However, as more regions of the world are converted to human use, we are also experiencing a shift in the traditional targets of conservation from protecting ‘ecologically intact’ landscapes to restoring degraded habitat by prioritizing conservation investments under triage. The overall goal of this thesis was to evaluate alternative ways of funding conservation initiatives. To reach that goal, I first used 1,770 avian point counts in a 2,520 km2 study area, remote-sensed data and models incorporating imperfect detectability to predict habitat occupancy in 47 widely-distributed native birds, which were also classified by experts according to their habitat association. Forest and Savannah association scores for these species were then used as weights in a composite distribution map of species communities. My results showed that composite maps of widespread indicators improve site prioritization by incorporating the behavioural and demographic responses of a diverse range of indicators to variation in patch size, configuration and adjacent human land use. Using these composite maps, I asked how the sale of forest carbon credits could reduce land acquisition costs, and how the alternate goals of maximizing α or β-diversity in focal communities could affect the prioritization of parcels for acquisition. My results indicate that carbon sales have the potential to enhance conservation outcomes in human-dominated landscapes by reducing the net acquisition costs of land conservation. Maximizing β versus α-diversity may further reduce costs by reducing the total area required to meet conservation targets and enhancing landscape heterogeneity. In cases where land purchase is not an option, private land conservation covenants can provide an alternative; although serious questions exist about long-term monitoring and enforcement costs of covenants given the risk that owners might violate or challenge them in court. My findings suggest that violation or dispute rate can substantially affect long-term costs of covenants and potentially surpass the cost of land purchase. Overall, I tested several ways to successfully fund conservation investments and highlight potential benefits and shortfalls of each.
NGC 1866: a milestone for understanding the chemical evolution of stellar populations in the LMC
Creators: name: Mucciarelli, A.
name: Cristallo, S.
name: Brocato, E.
name: Pasquini, L.
name: Straniero, O.
name: Caffau, E.
name: Raimondo, G.
name: Kaufer, A.
name: Musella, I.
name: Ripepi, V.
name: Romaniello, M.
name: Walker, A. R.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: We present new FLAMES@VLT spectroscopic observations of 30 stars in the field of the LMC stellar cluster NGC 1866. NGC 1866 is one of the few young and massive globular cluster that is close enough so that its stars can be individually studied in detail. Radial velocities have been used to separate stars belonging to the cluster and to the LMC field and the same spectra have been used to derive chemical abundances for a variety of elements, from [Fe/H] to the light (i.e. Na, O, Mg...) to the heavy ones. The average iron abundance of NGC 1866 turns out to be [Fe/H]= -0.43+-0.01 dex (with a dispersion of 0.04 dex), from the analysis of 14 cluster-member stars. Within our uncertainties, the cluster stars are homogeneous, as far as chemical composition is concerned, independent of the evolutionary status. The observed cluster stars do not show any sign of the light elements 'anti-correlation' present in all the Galactic globular clusters so far studied, and also found in the old LMC stellar clusters. A similar lack of anti-correlations has been detected in the massive intermediate-age LMC clusters, indicating a different formation/evolution scenario for the LMC massive clusters younger than ~3 Gyr with respect to the old ones. Also opposite to the Galactic globulars, the chemical composition of the older RGB field stars and of the young post-MS cluster stars show robust homogeneity suggesting a quite similar process of chemical evolution. The field and cluster abundances are in agreement with recent chemical analysis of LMC stars, which show a distinctive chemical pattern for this galaxy with respect to the Milky Way. We discuss these findings in light of the theoretical scenario of chemical evolution of the LMC.
description: Accepted for publication in the MNRAS (16 pages, 13 figures, 6 tables)
Low-energy dipole excitations in neon isotopes and N=16 isotones within the quasiparticle random phase approximation and the Gogny force
Creators: name: Martini, M.
name: Péru, S.
name: Dupuis, M.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: Low-energy dipole excitations in neon isotopes and N=16 isotones are calculated with a fully consistent axially-symmetric-deformed quasiparticle random phase approximation (QRPA) approach based on Hartree-Fock-Bogolyubov (HFB) states. The same Gogny D1S effective force has been used both in HFB and QRPA calculations. The microscopical structure of these low-lying resonances, as well as the behavior of proton and neutron transition densities, are investigated in order to determine the isoscalar or isovector nature of the excitations. It is found that the N=16 isotones 24O, 26Ne, 28Mg, and 30Si are characterized by a similar behavior. The occupation of the 2s_1/2 neutron orbit turns out to be crucial, leading to nontrivial transition densities and to small but finite collectivity. Some low-lying dipole excitations of 28Ne and 30Ne, characterized by transitions involving the neutron 1d_3/2 state, present a more collective behavior and isoscalar transition densities. A collective proton low-lying excitation is identified in the 18Ne nucleus.
Rotational spectrum of asymmetric top molecules in combined static and laser fields
Creators: name: Omiste, J. J.
name: González-Férez, R.
name: Schmelcher, P.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Chemical Physics (physics.chem-ph)
subject: FOS: Physical sciences

description: We examine the impact of the combination of a static electric field and a non resonant linearly polarized laser field on an asymmetric top molecule. Within the rigid rotor approximation, we analyze the symmetries of the Hamiltonian for all possible field configurations. For each irreducible representation, the Schrödinger equation is solved by a basis set expansion in terms of a linear combination of Wigner functions respecting the corresponding symmetries, which allows us to distinguish avoided crossings from genuine ones. Using the fluorobenzene and pyridazine molecules as prototypes, the rotational spectra and properties are analyzed for experimentally accessible static field strengths and laser intensities. Results for energy shifts, orientation, alignment and hybridization of the angular motion are presented as the field parameters are varied. We demonstrate that a proper selection of the fields gives rise to a constrained rotational motion in the three Euler angles, the wave function being oriented along the electrostatic field direction, and aligned in the other two angles.
description: 17 pages, 11 figures
Comment: How Should Indirect Evidence Be Used?
Creators: name: Kass, Robert E.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Methodology (stat.ME)
subject: FOS: Computer and information sciences

description: Indirect evidence is crucial for successful statistical practice. Sometimes, however, it is better used informally. Future efforts should be directed toward understanding better the connection between statistical methods and scientific problems. [arXiv:1012.1161]
description: Published in at http://dx.doi.org/10.1214/10-STS308C the Statistical Science (http://www.imstat.org/sts/) by the Institute of Mathematical Statistics (http://www.imstat.org)
Exploding Core-Collapse Supernovae with Jittering Jets
Creators: name: Papish, Oded
name: Soker, Noam
Publisher: name: arXiv
Year: 2011
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: We argue that jittering jets, i.e., jets that have their launching direction rapidly change, launched by the newly formed neutron star in a core collapse supernova can explode the star. We show that under a wide range of parameters the fast narrow jets deposit their energy inside the star via shock waves, and form two hot bubbles, that eventually merge, accelerate the rest of the star and lead to the explosion. To prevent the jets from penetrating through the collapsing stellar core and escape with their energy, instead of forming the hot bubbles, the jets should be prevented from drilling a hole through the star. This condition can be met if the jets' axis rapidly changes its direction. This process of depositing jets' energy into the ambient medium is termed the it penetrating jet feedback mechanism. The feedback exists in that the neutron star (or a black hole) at the center of the core collapse supernova shuts off its own growth by exploding the star. The jets deposit their energy at a distance of 1000 km from the center and expel the mass above that radius. In our model, the material near the stalled shock at several hundreds kilometers from the center is not expelled, but it is rather accreted and feed the accretion disk that blows the jets. The neutrinos might influence the accretion flow, but in the proposed model their role in exploding the star is small.
description: Accepted for publication in MNRAS
Fermion localization on a split brane
Creators: name: Chumbes, A. E. R.
name: Vasquez, A. E. O.
name: Hott, M. B.
Publisher: name: arXiv
Year: 2010
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: In this work we analyze the localization of fermions on a brane embedded in five-dimensional, warped and non-warped, space-time. In both cases we use the same nonlinear theoretical model with a non-polynomial potential featuring a self-interacting scalar field whose minimum energy solution is a soliton (a kink) which can be continuously deformed into a two-kink. Thus a single brane splits into two branes. The behavior of spin 1/2 fermions wavefunctions on the split brane depends on the coupling of fermions to the scalar field and on the geometry of the space-time.
description: 17 pages, 6 figures
Dissipated Correction Map Method with Trapezoidal Rule for the Simulations of Gravitational Waves from Spinning Compact Binary
Creators: name: Luo, Junjie
name: Zhang, Hong-Hao
name: Lin, Weipeng
Publisher: name: arXiv
Year: 2024
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences

description: The correction map method means extended phase-space algorithm with correction map. In our research, we have developed a correction map method, specifically the dissipated correction map method with trapezoidal rule, for numerical simulations of gravitational waves from spinning compact binary systems. This new correction map method, denoted as $CM3$, has shown remarkable performance in various simulation results, such as phase space distance, dissipated energy error, and gravitational waveform, closely resembling the high-order precision implicit Gaussian algorithm. When compared to the previously used midpoint map which denoted as $C_2$, the $CM3$ consistently exhibits a closer alignment with the highly accurate Gaussian algorithm in waveform evolution and orbital trajectory analysis. Through detailed comparisons and analyses, it is evident that $CM3$ outperforms other algorithms, including $CM2$ and $C_2$ mentioned in this paper, in terms of accuracy and precision in simulating spinning compact binary systems. The incorporation of the trapezoidal rule and the optimization with a scale factor $γ$ have significantly enhanced the performance of $CM3$, making it a promising method for future numerical simulations in astrophysics. With the groundbreaking detection of gravitational waves by the LIGO/VIRGO collaboration, interest in this research domain has soared. Our work contributes valuable insights for the application of matched filtering techniques in the analysis of gravitational wave signals, enhancing the precision and reliability of these detection.
Discovery of A Variable Broad Absorption Line in the BL Lac object PKS 0138-097
Creators: name: Shaohua, Zhang
name: Huiyuan, Wang
name: Hongyan, Zhou
name: Tinggui, Wang
name: Peng, Jiang
Publisher: name: arXiv
Year: 2011
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We report the discovery of a Broad Absorption Line (BAL) of \sim 10^4 km s-1 in width in the previously known BL Lac object PKS 0138-097, which we tentatively identified as a Mg II BAL. This is the first detection of a BAL, which is sometimes seen in powerful quasars with high accretion rates, in a BL Lac object. The BAL was clearly detected in its spectra of two epochs at a high luminosity state taken in the Sloan Digital Sky Survey (SDSS), while it disappeared in three SDSS spectra taken at a low luminosity state. The BAL and its variability pattern was also found in its historical multi-epoch spectra in the literature, but has been overlooked previously. In its high resolution radio maps, PKS 0138-097 shows a core plus an one-sided parsec-scale jet. The BAL variability can be interpreted as follows: The optical emission is dominated by the core in a high state and by the jet in a low state, and the BAL material is located between the core and jet so that the BAL appears only when the core is shining. Our discovery suggests that outflows may also be produced in active galactic nuclei at a low accreting state.
description: 7 page, 2 figures, 1 table
Improved Constraints on Isotropic Shift and Anisotropies of the Speed of Light using Rotating Cryogenic Sapphire Oscillators
Creators: name: Hohensee, Michael A.
name: Stanwix, Paul. L.
name: Tobar, Michael Edmund
name: Parker, Stephen R.
name: Phillips, David F.
name: Walsworth, Ronald L.
Publisher: name: arXiv
Year: 2010
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Data Analysis, Statistics and Probability (physics.data-an)
subject: FOS: Physical sciences

description: We demonstrate that Michelson-Morley tests, which detect direction-dependent anisotropies in the speed of light, can also be used to place limits upon isotropic deviations of the vacuum speed of light from $c$, as described by the photon sector Standard Model Extension (SME) parameter $\tildeκ_{tr}$. A shift in the speed of light that is isotropic in one inertial frame implies anisotropic shifts in others. Using observer Lorentz covariance, we derive the time-dependent variations in the relative resonance frequencies of a pair of electromagnetic resonators that would be generated by such a shift in the rest frame of the Sun. A new analysis of a recent experimental test of relativity using this result constrains $\tildeκ_{tr}$ with a precision of $7.4\times10^{-9}$. This represents the first constraint on $\tildeκ_{tr}$ by a Michelson-Morley experiment and the first analysis of a single experiment to simultaneously set limits on all nine non-birefringent terms in the photon sector of the SME.
A Practical Approach to Managing Spreadsheet Risk in a Global Business
Creators: name: Lemon, Thomas
name: Ferguson, Ewen
Publisher: name: arXiv
Year: 2010
Subjects: subject: Software Engineering (cs.SE)
subject: Computers and Society (cs.CY)
subject: FOS: Computer and information sciences

description: Spreadsheets are used extensively within today's organisations. Although spreadsheets have many benefits, they can also present a significant risk exposure, requiring appropriate management. Protiviti has worked with a number of organisations, ranging in size up to huge multi-nationals, to help them build appropriate spreadsheet governance frameworks, including the design and implementation of policies, minimum design standards, control processes, training and awareness programmes and the consideration and implementation of spreadsheet management tools. This paper presents a case-study explaining the practical and pragmatic approach that was recently taken to control spreadsheet risk at one of Protiviti's clients - a global energy firm.
description: 8 pages, 1 diagram; ISBN 978-1-905404-50-6
Scheduling links for heavy traffic on interfering routes in wireless mesh networks
Creators: name: Vieira, Fabio R. J.
name: de Rezende, José F.
name: Barbosa, Valmir C.
name: Fdida, Serge
Publisher: name: arXiv
Year: 2011
Subjects: subject: Networking and Internet Architecture (cs.NI)
subject: FOS: Computer and information sciences

description: We consider wireless mesh networks and the problem of scheduling the links of a given set of routes under the assumption of a heavy-traffic pattern. We assume some TDMA protocol provides a background of synchronized time slots and seek to schedule the routes' links to maximize the number of packets that get delivered to their destinations per time slot. Our approach is to construct an undirected graph G and to heuristically obtain node multicolorings for G that can be turned into efficient link schedules. In G each node represents a link to be scheduled and the edges are set up to represent every possible interference for any given set of interference assumptions. We present two multicoloring-based heuristics and study their performance through extensive simulations. One of the two heuristics is based on relaxing the notion of a node multicoloring by dynamically exploiting the availability of communication opportunities that would otherwise be wasted. We have found that, as a consequence, its performance is significantly superior to the other's.
Joint Bandwidth and Power Allocation with Admission Control in Wireless Multi-User Networks With and Without Relaying
Creators: name: Gong, Xiaowen
name: Vorobyov, Sergiy A.
name: Tellambura, Chintha
Publisher: name: arXiv
Year: 2010
Subjects: subject: Information Theory (cs.IT)
subject: FOS: Computer and information sciences

description: Equal allocation of bandwidth and/or power may not be efficient for wireless multi-user networks with limited bandwidth and power resources. Joint bandwidth and power allocation strategies for wireless multi-user networks with and without relaying are proposed in this paper for (i) the maximization of the sum capacity of all users; (ii) the maximization of the worst user capacity; and (iii) the minimization of the total power consumption of all users. It is shown that the proposed allocation problems are convex and, therefore, can be solved efficiently. Moreover, the admission control based joint bandwidth and power allocation is considered. A suboptimal greedy search algorithm is developed to solve the admission control problem efficiently. The conditions under which the greedy search is optimal are derived and shown to be mild. The performance improvements offered by the proposed joint bandwidth and power allocation are demonstrated by simulations. The advantages of the suboptimal greedy search algorithm for admission control are also shown.
description: 30 pages, 5 figures, submitted to IEEE Trans. Signal Processing in June 2010
title: Deutsche Ausbildungsmission im Irak / Oberst Dr. Uwe Hartmann [spricht] mit Oberst Frank Wasgindt
Creators: name: Hartmann, Uwe
name: Wasgindt, Frank
Publisher: name: ZMSBw
Year: 2023

description: Zugehört! : der Podcast des ZMSBw / Zentrum für Militärgeschichte und Sozialwissenschaften der Bundeswehr; 54
Voids in Coupled Scalar Field Cosmology
Creators: name: Li, Baojiu
Publisher: name: arXiv
Year: 2010
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We study the properties of voids in two different types of coupled scalar field theories. Due to the fifth force produced by the scalar field coupling, the matter particles feel stronger attraction amongst each other and cluster more quickly than they do in the standard LCDM model. Consequently voids in the coupled scalar field theories start to develop earlier and end up bigger, which is confirmed by our numerical simulations. We find that a significantly larger portion of the whole space is under-densed in the coupled scalar field theories and there are more voids whose sizes exceed given thresholds. This is more prominent in early times because at later times the under-dense regions have already been evacuated in coupled scalar field theories and there is time for the LCDM model to catch up. The coupled scalar field theories also predict a sharper transition between voids and high density regions. All in all, the qualitative behaviour is different not only from the LCDM result, but also amongst specific coupled scalar field models, making voids a potential candidate to test alternative ideas about the cosmic structure formation.
description: 11 pages, 5 figures, 1 table
Double white dwarf mergers and elemental surface abundances in extreme helium and R Coronae Borealis stars
Creators: name: Jeffery, C. Simon
name: Karakas, Amanda I.
name: Saio, Hideyuki
Publisher: name: arXiv
Year: 2011
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: The surface abundances of extreme helium (EHe) and R Coronae Borealis (RCB) stars are discussed in terms of the merger of a carbon-oxygen white dwarf with a helium white dwarf. The model is expressed as a linear mixture of the individual layers of both constituent white dwarfs, taking account of the specific evolution of each star. In developing this recipe from previous versions, particular attention has been given to the inter-shell abundances of the asymptotic giant branch star which evolved to become the carbon-oxygen white dwarf. Thus the surface composition of the merged star is estimated as a function of the initial mass and metallicity of its progenitor. The question of whether additional nucleosynthesis occurs during the white dwarf merger has been examined. The high observed abundances of carbon and oxygen must either originate by dredge-up from the core of the carbon-oxygen white dwarf during a cold merger or be generated directly by alpha-burning during a hot merger. The presence of large quantities of O18 may be consistent with both scenarios, since a significant O18 pocket develops at the carbon/helium boundary in a number of our post-AGB models. The production of fluorine, neon and phosphorus in the AGB intershell produces n overabundance at the surface of the merged stars, but generally not in sufficient quantity. However, the evidence for an AGB origin for these elements points to progenitor stars with initial masses in the range 1.9 - 3 solar masses. There is not yet sufficient information to discriminate the origin (fossil or prompt) of all the abundance anomalies observed in EHe and RCB stars. Further work is required on argon and s-process elements in the AGB intershell, and on the predicted yields of all elements from a hot merger.
description: 20 pages, 8 figures, 3 tables, MNRAS in press
A systematic study of silicon germanium interdiffusion for next generation semiconductor devices
Creators: name: Dong, Yuanwei
Publisher: name: University of British Columbia
Year: 2014

description: SiGe heterostructures with higher Ge fractions and larger Ge modulations, and thus higher compressive stress, are key structures for next-generation electronic and optoelectronic devices. Si-Ge interdiffusion during high temperature growth or fabrication steps changes the distribution of Ge fraction and stress, and increases atomic intermixing, which degrades device performance. It is of technological importance to study Si-Ge interdiffusion behaviours and build accurate Si-Ge interdiffusivity models. In this work, three aspects of Si-Ge interdiffusion behaviours were investigated both by experiments and by theoretical analysis. 1) Based on the correlation between self-diffusivity, intrinsic diffusivity and interdiffusivity in binary alloy systems, a unified interdiffusivity model was built over the full Ge fraction range. It provides a zero-strain, no-dopant-effect, and low-dislocation-density reference for studies of more impacting factors. This model was then validated with literature data and our experimental data using different annealing techniques. Next, with the well-established reference, the impact of biaxial compressive strain on Si-Ge interdiffusion was further investigated under two specific strain scenarios: with full coherent strain and with partial strain. 2) Complete theoretical analysis was presented to address the compressive strain’s role in Si-Ge interdiffusion. The role of compressive strain was modeled in two aspects: a) strain energy contributes to the interdiffusion driving force; b) the strain derivative q' of interdiffusivity, reflecting the strain-induced changes of both prefactor and activation energy. For the temperature range (720 °C to 880 °C) and Ge fraction range (0.36 to 0.75), a temperature dependence of the strain derivative q', q'=-0.081T+110 eV/unit strain, was reported in Si-Ge interdiffusion. 3) For the case with partial strain, the apparent interdiffusivity model developed for the case with full coherent strain in 2) was modified to reflect strain change, and it was then validated with experimental data. In summary, a set of interdiffusivity models were established based on experimental data and theoretical analysis for three strain scenarios. These models can be employed to predict the thermal stability of SiGe heterostructures, and optimize the design of SiGe structures and of thermal budgets for next-generation SiGe based devices.
Solar Dynamics Observatory discovers thin high temperature strands in coronal active regions
Creators: name: Reale, Fabio
name: Guarrasi, Massimiliano
name: Testa, Paola
name: DeLuca, Edward E.
name: Peres, Giovanni
name: Golub, Leon
Publisher: name: arXiv
Year: 2011
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: One scenario proposed to explain the million degrees solar corona is a finely-stranded corona where each strand is heated by a rapid pulse. However, such fine structure has neither been resolved through direct imaging observations nor conclusively shown through indirect observations of extended superhot plasma. Recently it has been shown that the observed difference in appearance of cool and warm coronal loops (~1 MK, ~2-3 MK, respectively) -- warm loops appearing "fuzzier" than cool loops -- can be explained by models of loops composed of subarcsecond strands, which are impulsively heated up to ~10 MK. That work predicts that images of hot coronal loops (>~6 MK) should again show fine structure. Here we show that the predicted effect is indeed widely observed in an active region with the Solar Dynamics Observatory, thus supporting a scenario where impulsive heating of fine loop strands plays an important role in powering the active corona.
description: 11 pages, 4 figures, accepted for publication
title: The Field Guide App - Connecting Island Communities to Local Conservation Through Mobile Interaction
Creators: name: Sousa, Daniel
name: Silva, Alexandra R.
name: Amorim, Isabel R.
name: Ashby, Simone
name: Arroz, Ana Moura
name: Piasentin, Flora
name: Gabriel, Rosalina
name: Matos, Sónia
Publisher: name: EUSSET
Year: 2021
Subjects: subject: Mobile interaction
subject: nature conservation
subject: science communication
subject: place-based learning
subject: ‘ask a scientist’

description: Here we present Field Guide, a mobile application (app) designed to connect communities to nature-rich environments, which play a crucial role in nature conservation efforts. The app aligns to a mode of science communication that seeks to establish direct contact between publics and specialised scientific communities, most commonly known as the ’ask a scientist’ approach. Field Guide uses a geolocation positioning system to offer users the opportunity to pose questions to scientists whilst exploring a nature conservation site. In this demo, we display the app as a mock-up presentation before its first use by children and teenagers during a field-trip to a nature trail later in 2021.