cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Data-driven group analysis of complex-valued fMRI data
Creators: name: Rodriguez, Pedro Angel
Publisher: name: Maryland Shared Open Access Repository
Year: 2013
Subjects: complex-valued
constrained
denoising
fMRI
ica
phase

description: Analysis of functional magnetic resonance imaging (fMRI) data in its native, complex form has been shown to increase the sensitivity of the analysis both for data-driven techniques such as independent component analysis (ICA) and for model-driven techniques. The promise of an increase in sensitivity and specificity in clinical studies provides a powerful motivation for utilizing both the phase and magnitude data; however, the unknown and noisy nature of the phase poses a challenge for successful study of the fMRI data. In addition, complex-valued analysis algorithms, such as ICA, suffer from an inherent phase ambiguity, which introduces additional difficulty for group analysis and visualization of the results. We present solutions for these issues, which have been among the main reasons phase information has been traditionally discarded, and show their effectiveness when used as part of a complex-valued group ICA algorithm application. The developed methods become key components of a framework that allows the development of new fully complex data-driven and semi-blind methods to process, analyze, and visualize fMRI data. In this dissertation, we first introduce the methods developed as part of the fully complex framework for ICA of fMRI data. We introduce a physiologically motivated de-noising method that uses phase quality maps to successfully identify and eliminate noisy voxels--3D pixels--in the fMRI complex images so they can be used in individual and group studies. We also introduce a phase correction scheme that can be either applied sub-sequent to ICA of fMRI data or can be incorporated into the ICA algorithm in the form of prior information to eliminate the need for further processing for phase correction. Finally, we present two visualization methods that are used to augment the sensitivity and specificity in the detection of activated voxels. We show the benefits of using the developed methods on actual complex-valued fMRI data. In the remainder of the dissertation, we focus on developing constrained ICA (C-ICA) algorithms for complex-valued fMRI data. C-ICA uses prior information, hence providing a balance between model-based and data-driven approaches such as ICA to improve the source estimation performance and robustness to noise. C-ICA algorithms have been used to improve the estimation performance in real-valued fMRI data, but--to our knowledge--have not been applied to complex-valued fMRI data. We develop the first C-ICA algorithm that uses complex-valued references to constrain either the sources or the mixing coefficients. The designed algorithm is not restricted to having a unitary demixing matrix, which is a major assumption in existing C-ICA algorithms. We show, on both simulated and actual fMRI data, how the performance of ICA improves by using prior information about the fMRI paradigm.
The flux-tube phase transition
Creators: name: Kozlov, G. A.
name: Khoriauli, G.
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We consider the phase transition in the "hot" dual long-distances Yang-Mills theory at finite temperature $T$. This phase transition is associated with a change of symmetry. The dual model is formulated in terms of two-point Wightman functions with equations of motion involving higher derivatives. The effective mass of the dual gauge field is derived as a function of $T$-dependent gauge coupling constant.
description: Based on the talk presented at the Conference "Quark Confinement and Hadron Spectrum VII", Ponta Delgada, Azores, Portugal, September 2-7, 2006. To be published in AIP. (9 pages, 4 figures)
Characteristics of Burley Tobacco Farms
Creators: name: Capehart, Tom
name: Capehart, Tom
Publisher: name: Unknown
Year: 1991
Subjects: Agricultural and Food Policy
Crop Production/Industries
Farm Management
Production Economics

description: Burley tobacco is the second most important kind of tobacco grown in the United States and is an important component in American blend cigarettes that are increasingly popular worldwide. Burley tobacco is grown in eight States, but Kentucky and Tennessee accounted for 86 percent of U.S. production in 1990. The average burley farm plants only about 3 acres in burley tobacco, producing about 6,500 pounds worth just over $10,000. Farmers typically grow burley in conjunction with other crop or live- stock enterprises. This report examines the structure and characteristics of burley tobacco farming in Kentucky and Tennessee using data from the 1989 Farm Costs and Returns Survey and makes comparisons with data from previous years' surveys.
Scikit-network: Graph Analysis in Python
Creators: name: Bonald, Thomas
name: de Lara, Nathan
name: Lutz, Quentin
name: Charpentier, Bertrand
Publisher: name: arXiv
Year: 2020
Subjects: subject: Social and Information Networks (cs.SI)
subject: FOS: Computer and information sciences

description: Scikit-network is a Python package inspired by scikit-learn for the analysis of large graphs. Graphs are represented by their adjacency matrix in the sparse CSR format of SciPy. The package provides state-of-the-art algorithms for ranking, clustering, classifying, embedding and visualizing the nodes of a graph. High performance is achieved through a mix of fast matrix-vector products (using SciPy), compiled code (using Cython) and parallel processing. The package is distributed under the BSD license, with dependencies limited to NumPy and SciPy. It is compatible with Python 3.6 and newer. Source code, documentation and installation instructions are available online.
Understanding Latina Immigrant Mothers' Involvement in their Children's Preschool Education
Creators: name: Ramos, Manica Felicia
Publisher: name: Maryland Shared Open Access Repository
Year: 2013
Subjects: Education
Immigrant
Latino
Parental engagement
Parental involvement
Preschool

description: The overall goal of the present study was to examine Latina immigrant mothers' involvement in their children's preschool education, including how they were involved, the factors that motivated their involvement, and whether they encountered barriers to being involved. Both quantitative and qualitative methods were utilized; this mixed-method approach allowed for an enriched, elaborated understanding of the parental involvement of Latina immigrant mothers. Forty-three foreign - born Latina mothers with children attending a bilingual urban preschool program were interviewed one time. Latina mothers supported their children's education in various ways, including forms of parental involvement that have been established (e.g., home-based, school-based, and home-school conferencing) as well as alternative cultural models of parental involvement that are embedded within cultural values and beliefs (e.g., apoyo, consejos, and sacrificios). The factors that motivate parents' involvement (i.e., self -efficacy, role construction, and invitation for involvement) varied by the form of involvement being examined.  Specifically, mothers' reported self-efficacy was related to home-based involvement. Knowledge and skill was related to school-based involvement. Mothers reported lacking time and energy due to work demands and schedules as the main barrier to their involvement. The findings of the present study highlight the need to understand the ways Latina parents support their children's education that may be informed by cultural values and community norms. By doing so we will acknowledge a more diverse set of parental involvement behaviors than are typically examined in research and visible to teachers. An expanded definition of parental involvement may be used to inform programs that seek culturally and contextually appropriate ways to engage Latina immigrant families in their children's education.
Ecology and conservation of endangered forty-spotted pardalotes
Creators: name: Edworthy, Amanda Brooke
Publisher: name: The Australian National University
Year: 2017

description: The forty-spotted pardalote (Pardalotus quadragintus) is an endangered songbird endemic to eastern Tasmania. These birds specialize on forests containing Eucalyptus viminalis (white gum tree) for foraging, and require tree cavities for nesting. They have experienced both historical range contraction following European settlement and recent population decline within existing habitat. Causes of this decline are uncertain. Ecological theory predicts that habitat specialists will be most vulnerable to habitat loss, rather than factors that disrupt the balance of fecundity and mortality. However, cavity-nesting birds tend to invest heavily in individual nest attempts, and as a result, may be vulnerable to competitors, predators, or parasites which attack the nest. To examine current threats to forty-spotted pardalotes, I conducted three seasons of fieldwork in southeastern Tasmania, monitoring the breeding biology of forty-spotted pardalotes and their generalist competitors, striated pardalotes (Pardalotus striatus). I also collected blood samples from forty-spotted pardalotes to examine their population structure and demographic history. A model presentation experiment and observations of nest takeovers revealed that striated pardalotes were the dominant competitor and usurped 10% of forty-spotted pardalote nests, whereas forty-spotted pardalotes never usurped striated pardalotes. However, the largest source of nest failure was a native ectoparasitic fly (Passeromyia longicornis) which killed 81% of nestlings. Encouragingly, I found that forty-spotted pardalotes occupied nest boxes, resulting in high breeding densities and similar nest success compared to natural cavities. Finally, I developed a dataset of 57,868 SNPs from 159 individual birds sampled throughout major populations in southeastern Tasmania. Despite its larger population size, Maria Island had the least genetic diversity of any population, and there was no evidence of migrants between it and the southern populations. There was little population differentiation and substantial gene flow between Bruny Island and the nearby mainland populations, as well as evidence of ancestry from an extirpated mainland population. This study shows that conservation of habitat specialists needs to include protection of habitat features such as tree cavities and the extent of E. viminalis forest, but also needs to address threats within existing habitat, such as nest parasites. My finding that a native fly parasite is the principal source of mortality forty-spotted pardalote nestlings adds to growing concern about the increasing impacts of avian ectoparasites on their hosts in island systems.
Identifying Malware Using N-Gram Clustering Metrics
Creators: name: Dowd, Christopher
Publisher: name: Maryland Shared Open Access Repository
Year: 2014
Subjects: Clustering
Computer Science
Malware Analysis
N Gram
Similarity Matrix

description: We identify a new method for detecting malware within a network that can be processed in linear time. In the digital age, more files are transferred between individuals and systems that have the potential to contain malignant processes. Traditional malware detection and analysis is performed by signature based operations or by hashing current files. A malicious attacker can quickly change found signatures or change various processes to defeat hash based detection. We need a way to quickly identify malicious files to stage them for quarantine and further analysis. In this thesis we observe the previous methods used to detect malware and develop a new process to identify malware using n-gram analysis to cluster malware specimens by their similarity to each other. Specimens from a well-known malware family are used in this demonstration.
Sedimentary tracers of sewage inputs to the southern Strait of Georgia
Creators: name: Gordon, Kathleen
Publisher: name: University of British Columbia
Year: 2009

description: Sewage effluent has been discharged at depth to the Strait of Georgia just south of Vancouver since 1988, following primary treatment at the Iona Island Sewage Treatment Plant. The discharge is accomplished through a pair of semi-parallel diffusers between water depths of ~ 70 m and ~ 105 m that lie orthogonal to the bottom contours on the foreslope of the Fraser River Delta. Prior to the research reported here, knowledge was limited as to the transport pathways and depositional fate of the particulate matter in the effluent. Thus, the objective of this work is to investigate and apply a suite of sewage-specific tracers, in particular silver, stable carbon and nitrogen isotopes, and more commonly-considered contaminant metals (Cu, Pb and Zn) in an effort to define better the depositional footprint of the Iona sewage in southern Georgia Strait. Silver has the highest relative enrichment of any metal in sewage, and is expected to be an ideal candidate as a sewage tracer. That this is the case here is borne out by a well-defined band of high Ag concentrations (~ 400-800 ng/g) in sediments that extends along the foreslope north of the outfall by ~ 6 km and south by ~ 1 km. This pattern reflects transport of the effluent plume predominantly to the north with little lateral dispersion. The accumulation of silver in this area is unlikely to be due to authigenic precipitation of Ag2S or other sulphide phases, but is instead attributed to direct deposition of a very small amount of particulate sewage in which the silver content is highly enriched. Very high silver concentrations (1, 400 ng/g) are also observed in an area of Sturgeon Bank close to the Iona Island plant, where direct discharge of sewage occurred prior to 1988. In contrast, very low levels (~ 50 ng/g) are found in coarse-grained lag deposits in shallow regions of the delta. Sediments in the deep central basin of the Strait of Georgia host concentrations on the order of 130 ng/g. Significant enrichments of manganese oxides in the surface sediments of some cores from the central Strait are not matched by enhanced silver concentrations, suggesting that silver is minimally associated with manganese oxide phases in marine sediments. Neither stable carbon arid nitrogen isotope distributions nor concentration patterns for Cu, Pb and Zn show any associations in the Strait of Georgia with the pattern of sewage deposition defined by the silver data. The lack of sensitivity of these two groups of potential tracers is attributed to a coupling between low signal to background ratios and the substantial discharge of sediments (some 20 x 10^ m^/year) from the Fraser River which dwarfs sewage-specific inputs of the trace metals and the isotopes. Thus, of the various tracers investigated in this research, silver is uniquely appropriate.
Quantum continual measurements: the spectrum of the output
Creators: name: Barchielli, Alberto
name: Gregoratti, Matteo
Publisher: name: arXiv
Year: 2008
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: When a quantum system is monitored in continuous time, the result of the measurement is a stochastic process. When the output process is stationary, at least in the long run, the spectrum of the process can be introduced and its properties studied. A typical continual measurement for quantum optical systems is the so called homodyne detection. In this paper we show how the Heisenberg uncertainty relations give rise to characteristic bounds on the possible homodyne spectra and we discuss how this is related to the typical quantum phenomenon of squeezing.
description: 13 pages, 2 figures. Submitted to the proceedings of the 28-th Conference on Quantum Probability and Related Topics, 2-8 september 2007, CIMAT-Guanajuato, MEXICO
Low-Redshift Constraints on Covariant Canonical Gauge Theory of Gravity
Creators: name: Benisty, David
name: Vasak, David
name: Kirsch, Johannes
name: Struckmeier, Jurgen
Publisher: name: arXiv
Year: 2021
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Constraints on the Covariant Canonical Gauge Gravity (CCGG) theory from low-redshift cosmology are studied. The formulation extends Einstein's theory of General Relativity (GR) by a quadratic Riemann-Cartan term in the Lagrangian, controlled by a "deformation" parameter. In the Friedman universe this leads to an additional geometrical stress energy and promotes, due to the necessary presence of torsion, the cosmological constant to a time-dependent function. The MCMC analysis of the combined data sets of Type Ia Supernovae, Cosmic Chronometers and Baryon Acoustic Oscillations yields a fit that is well comparable with the $Λ$CDM results. The modifications implied in the CCGG approach turn out to be subdominant in the low-redshift cosmology. However, a non-zero spatial curvature and deformation parameter are shown to be consistent with observations.
description: 9 pages; 5 figures
CogNovo – A Case Study for Cognitive Innovation
Creators: name: Loesche, Frank
name: Torre, Ilaria
name: Maranan, Diego S.
name: Denham, Susan
Publisher: name: Zenodo
Year: 2017

description: Cognitive innovation is a term artificially created to describe an integrative concept linking ideation, implementation, and communication across disciplines (Gummerum & Denham, 2014). While the mentioned sub-parts have been subjects of discussion across a number of research areas, so far the fields have not tackled the combined concept with great success. In part this is attributed to a missing methodological approach. CogNovo, a doctoral training centre at Plymouth University, is set up in a way that it provides access to 25 PhD students and their supervisors practising cognitive innovation in their work across disciplines (Maranan, Loesche,& Denham, 2015). Here we show the elements of the setup from a information theoretical perspective with the input, process, and output specified. We suggest a mixed-methods approach to understand cognitive innovation as more than the sum of its parts.
description: This work was supported by Cog Novo (FP7-PEOPLE-2013-ITN-604764), a project funded by the EU Marie Sktodowska Curie programme. Diego Maranan is additionally associated with the Faculty of Information and Communication Studies at the University of the Philippines Open University.
DATA INTENSIVE SCIENTIFIC COMPUTE MODEL FOR MULTICORE CLUSTERS
Creators: name: Nguyen, Phuong T.
Publisher: name: Maryland Shared Open Access Repository
Year: 2012
Subjects: climate changes
data intensive
hadoop scheduler
MapReduce
scheduling algorithm
workflow system

description: Data intensive computing holds the promise of major scientific breakthroughs and discoveries from the exploration and mining of the massive data sets becoming available to the science community. This expectation has led to tremendous increases in data intensive scientific applications. However, data intensive scientific applications still face severe challenges in accessing, managing and analyzing petabytes of data. In particular, workflow systems to support such scientific applications are not as efficient when dealing with thousands and even more of complex tasks within jobs that operate across high performance large multicore clusters with very large amounts of streaming data. Scheduling, it turns out, is an integral workflow component in the execution often of thousands or more tasks within a data intensive scientific application as well as in managing the access and flow of many jobs to the available resource environment. Recently, MapReduce systems such as Hadoop, have proven successful for many business data intensive problems. However, there are still many limitations in the use of MapReduce systems for data-intensive scientific problems mainly because they do not support the characteristics of science such as data formats, specialized data analytic tools (e.g. math libraries), accuracies, and interfaces with non MapReduce components.    This thesis addresses some of these limitations by proposing a MapReduce workflow model and its runtime system using Hadoop for orchestrating MapReduce jobs for data intensive scientific workflows. A heuristic based scheduling algorithm is proposed in the workflow system to manage the execution of data intensive scientific applications. This thesis has developed a hybrid-scheduling algorithm based on run time dynamic priorities, proportional resource sharing techniques that reduce delays for variable length concurrent tasks, and takes advantage of data locality. As a result, a new scheduling policy, Balanced Closer to Finish First (BCFF), is proposed as solutions for some problems of scheduling in MapReduce environment. The scheduling algorithm is implemented in Hadoop 1.0.1 framework as a new Hadoop 1.0.1 plug-in Scheduler. The evaluations of the workflow system on the climate data processing and analysis application (several TB dataset) show that it is feasible and significantly improved compared to traditional parallel processing method. The scientific results of the application provide new source of monitoring global climate changes for the near decade 2002-2011.
Brachytrupes mauritanicus Chopard 1952, stat. nov.
Creators: name: Simeu-Noutchom, Alain
name: Heller, Klaus-Gerhard
name: Nyobe, Philene Corinne Aude Um
name: Kekeunou, Sevilor
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Orthoptera
Gryllidae
Brachytrupes
Brachytrupes mauritanicus

description: Species Brachytrupes mauritanicus Chopard, 1952 stat. nov. (Table 2, Fig. 4)
Brachytrypes membranaceus mauritanicus Chopard. 1952: p. 465
Type material: syntypes (1 male, 1 female), Africa, West Tropical Africa, Sierra Leone, MNHN (male listed as holotype)
Description (Chopard 1952). Body quite small, color entirely testaceous yellowish with a brown stripe along the posterior edge of the pronotum. Head large, almost alike in both sexes, yellow, with a narrow brown band between the eye spots; the tubercles bearing these ocelli are very weak in the male, nil in the female; forehead somewhat concave, with projecting edges; upper edge of the clypeus narrowly edged with brown. Pronotum rather greatly enlarged in front, the anterior edge concave, very narrowly brown, the posterior edge a little sinuate. Legs completely yellowish; reinforcement of the posterior tibiae weak, especially at the external edge; posterior metatarsus armed with 3 or 4 weak spinules on each superior edge. Mirror as wide as long, less elongated and more rounded in front; apical field veins very regular.
description: Published as part of Simeu-Noutchom, Alain, Heller, Klaus-Gerhard, Nyobe, Philene Corinne Aude Um & Kekeunou, Sevilor, 2023, Taxonomy review of the genus Brachytrupes (Orthoptera: Gryllidae) with the description of a new species and key to the species, pp. 373-388 in Zootaxa 5336 (3) on page 380, DOI: 10.11646/zootaxa.5336.3.4, http://zenodo.org/record/8281577
Understanding Adolescent Mothers' Parenting: An Examination of Cognitive Readiness, Attributions, and Parenting Behaviors
Creators: name: Rose, Laura E
Publisher: name: Maryland Shared Open Access Repository
Year: 2014
Subjects: adolescent parenting
attributions
cognitive readiness

description: The overall goals of the present study were to examine whether differences in adolescent mothers' cognitions (readiness and attributions) affected their parenting behaviors, and whether such differences could be explained by the context of a given situation. Both self-report and observational data were utilized to address the goals across two parts. The sample for Part One was comprised of 142 primiparous, African American mothers between 14 and 22 years of age with children between 2-25 months. Results revealed that specific cognitive readiness variables were stronger predictors of perceived parenting behaviors than the combined effect of cognitive readiness, comprised of parenting knowledge, parenting attitudes, and maternal age. Direct and indirect effects of internal and external attributions for failures in the relation between cognitive readiness variables and perceived parenting behaviors were also observed. These findings illustrate specificity in the processes through which adolescent mothers' cognitions affect their perceptions of their parenting behaviors. Forty-nine of the mothers from Part One participated in the observational component with their toddlers and comprised the sample for Part Two. The cluster analysis statistical method revealed four parenting cognition profiles: (1) Unprepared, Younger, Low Attribution Mothers, (2) Unprepared, Older, Low Attribution Mothers, (3) Prepared, Older, High Attribution Mothers, and (4) Unprepared, Younger, High Attribution Mothers. Results highlight the importance of acknowledging heterogeneity among adolescent mothers that has been overlooked in past research. Although there were no differences in patterns of observed parenting behaviors among clusters or by observational context, these nonsignificant findings may have been a result of low power. Findings from the present study can provide important information to guide the development of interventions that focus on enhancing parents' cognitive readiness and promoting adaptive parenting attributions, which in turn, could lead to more optimal parenting behaviors.
Alpha-Cluster formation in heavy alpha-emitters within a multistep model
Creators: name: Dong, J. M.
name: Zhao, Q.
name: Wang, L. J.
name: Zuo, W.
name: Gu, J. Z.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: $α$-decay always has enormous impetuses to the development of physics and chemistry, in particular due to its indispensable role in the research of new elements. Although it has been observed in laboratories for more than a century, it remains a difficult problem to calculate accurately the formation probability $S_α$ microscopically. To this end, we establish a new model, i.e., multistep model, and the corresponding formation probability $S_α$ values of some typical $α$-emitters are calculated without adjustable parameters. The experimental half-lives, in particular their irregular behavior around a shell closure, are remarkably well reproduced by half-life laws combined with these $S_α$. In our strategy, the cluster formation is a gradual process in heavy nuclei, different from the situation that cluster pre-exists in light nuclei. The present study may pave the way to a fully understanding of $α$-decay from the perspective of nuclear structure.
description: 7 pages, 4 figures
Deliverable D8.1: Successful implementation of CS ELSI and procedures for data protection, record and sample retrieval, and for record and sample withdrawal from the Biobank
Creators: name: Akyüz, Kaya
name: Mayrhofer, Michaela Th.
Publisher: name: Zenodo
Year: 2021

description: This report describes the implementation of ethical, legal, and societal implications (ELSI) recommendations, procedures for data protection, record and sample retrieval and for record and sample withdrawal from the biobank. In this regard, BBMRI-ERIC’s ELSI Services & Research1 experts2 guided and advised the CY-Biobank project consortium on harmonizing and monitoring its procedures, specifically on consent process, incidental findings, risk assessment, composition of independent ethics committees, Data Protection Impact Assessment (DPIA), inclusion of minors/vulnerable groups in research, general ethical principles, and the GPDR implementation. Medical University Graz (MUG) and Biobank Graz provided input that relates to topics such as sensitive aspects arising from large number of participants and further guidance, e.g., on Clinical Trial Directive and Commission Directive 2005/28/EC. CY-Biobank personnel ensured working coherently towards the goals of the work package in preparing and updating the Biobank documentation, applying recommended procedures and regulations and striving towards increased transparency and openness.
Ground-State Shapes and Structures of Colloidal Domains
Creators: name: Wu, Jianlan
name: Cao, Jianshu
Publisher: name: arXiv
Year: 2006
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: FOS: Physical sciences

description: In charged colloidal suspensions, the competition between square-well attraction and long-range Yukawa repulsion leads to various stable domains and Wigner supercrystals. Using a continuum model and symmetry arguments, a phase diagram of spheres, cylinders, and lamellae is obtained as a function of two control parameters, the volume fraction and the ratio between the surface tension and repulsion. Above a critical value of the ratio, the microphase cannot be supported by the Yukawa repulsion and macroscopic phase separation occurs. This finding quantitatively explains the lack of pattern formation in simple liquids because of the small hard sphere diameter in comparison with the size of macromolecules. The phase diagram also predicts microphase separation at zero value of the ratio, suggesting the possibility of self-assembly in repulsive systems.
description: 4 pages and 4 figures
Accessing topological surface states and negative MR in sculpted nanowires of Bi2Te3 at ultra-low temperature
Creators: name: Yadav, Reena
name: Bhattacharyya, Biplab
name: Pandey, Animesh
name: Kaur, Mandeep
name: Aloysius, R. P.
name: Gupta, Anurag
name: Husale, Sudhir
Publisher: name: arXiv
Year: 2020
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Milling of 2D flakes is a simple method to fabricate nanomaterial of any desired shape and size. Inherently milling process can introduce the impurity or disorder which might show exotic quantum transport phenomenon when studied at the low temperature. Here we report temperature dependent weak antilocalization (WAL) effects in the sculpted nanowires of topological insulator in the presence of perpendicular magnetic field. The quadratic and linear magnetoconductivity (MC) curves at low temperature indicate the bulk contribution in the transport. A cusp feature in magnetoconductivity curves (positive magnetoresistance) at ultra low temperature and at magnetic field, less than 1T represent the WAL indicating the transport through surface states. The MC curves are discussed by using the 2D Hikami Larkin Nagaoka theory. The crossover interplay nature of positive and negative magnetoresistance observed in the MR curve at ultra low temperature. Our results indicate that transport through topological surface states (TSS) in sculpted nanowires of Bi2Te3 can be achieved at mK range and linear MR observed at 2 K could be the coexistence of electron transport through TSS and contribution from the bulk band.
description: 8 pages 3 fig
Investigations of NMR T1 relaxation mechanisms in oil- and water-wet sand packs
Creators: name: Caputi, Michael Burns
Publisher: name: University of British Columbia
Year: 2009

description: The proton NMR relaxation parameter T, is affected by both relaxation in the bulk pore fluid and relaxation associated with the surface of the pore space. An understanding of the relative importance of these two relaxation mechanisms is a critical part of interpreting the NMR response of fluid saturated porous rocks. The first part of the thesis was an experimental study of the relaxation of protons in a sand pack filled with pyrite. Both oil- and water-wet sand packs exhibited a decrease in relaxation times of the pore fluid as the amount of pyrite in the sand was increased. I believe that the oxidation product of pyrite, Fe³⁺, is the critical component in governing the relaxation mechanism in these sand packs. The Fe³⁺ is going into solution and filling the pore fluid, decreasing the bulk solution relaxation time of the pore fluid. The Fe³⁺ is also believed to be adsorbing to the oil-water and water-sand interfaces, enhancing the surface-induced relaxation mechanisms in the oil- and water-wet sand packs. The second part of the thesis concentrated on understanding relaxation mechanisms in oil- and water-wet sand packs with pore fluids of differing pH and salinity. Changes in salinity of the pore fluid proved to have no effect on either the bulk solution or surface-induced relaxation mechanisms. Low pH pore fluid in the oil- and water-wet sands appears to bring paramagnetic species from the oil-water and water-sand interfaces into solution, decreasing bulk solution relaxation times of the pore fluids. The magnitude of the surface-induced relaxation mechanisms, quantified by determining the surface relaxivity, also increases in strength with the decrease in pore fluid pH.
Self-organization of price fluctuation distribution in evolving markets
Creators: name: Pan, Raj Kumar
name: Sinha, Sitabhra
Publisher: name: arXiv
Year: 2006
Subjects: subject: Physics and Society (physics.soc-ph)
subject: Other Condensed Matter (cond-mat.other)
subject: Statistical Finance (q-fin.ST)
subject: FOS: Physical sciences
subject: FOS: Economics and business

description: Financial markets can be seen as complex systems in non-equilibrium steady state, one of whose most important properties is the distribution of price fluctuations. Recently, there have been assertions that this distribution is qualitatively different in emerging markets as compared to developed markets. Here we analyse both high-frequency tick-by-tick as well as daily closing price data to show that the price fluctuations in the Indian stock market, one of the largest emerging markets, have a distribution that is identical to that observed for developed markets (e.g., NYSE). In particular, the cumulative distribution has a long tail described by a power law with an exponent $α\approx 3$. Also, we study the historical evolution of this distribution over the period of existence of the National Stock Exchange (NSE) of India, which coincided with the rapid transformation of the Indian economy due to liberalization, and show that this power law tail has been present almost throughout. We conclude that the ``inverse cubic law'' is a truly universal feature of a financial market, independent of its stage of development or the condition of the underlying economy.
description: 5 pages, 5 figures, Published version, typos corrected
Letter from W. R. Megaw to "Sir" [F. A. Hewer], April 16, 1909
Creators: name: Megaw, W.R.
Publisher: name: The University of British Columbia
Year: 2017

description: Letter to "Sir" [F. A. Hewer] from W. R. Megaw, dated April 16, 1909, telling F. A. Hewer that his order of wheat has been shipped.
Reconstructing Dark Energy
Creators: name: Sahni, Varun
name: Starobinsky, Alexei
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: This review summarizes recent attempts to reconstruct the expansion history of the Universe and to probe the nature of dark energy. Reconstruction methods can be broadly classified into parametric and non-parametric approaches. It is encouraging that, even with the limited observational data currently available, different approaches give consistent results for the reconstruction of the Hubble parameter $H(z)$ and the effective equation of state $w(z)$ of dark energy. Model independent reconstruction using current data allows for modest evolution of dark energy density with redshift. However, a cosmological constant (= dark energy with a constant energy density) remains an excellent fit to the data. Some pitfalls to be guarded against during cosmological reconstruction are summarized and future directions for the model independent reconstruction of dark energy are explored.
description: 28 pages, 7 figures; Invited review for the special issue of Int. J. Mod. Phys. devoted to dark energy and dark matter, IJMP style. Additional references, more discussion
QED interaction effects on heavy meson masses from lattice QCD+QED
Creators: name: Hatton, D.
name: Davies, C. T. H.
name: Lepage, G. P.
Publisher: name: arXiv
Year: 2020
Subjects: subject: High Energy Physics - Lattice (hep-lat)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Hadron masses are subject to few MeV corrections arising from QED interactions, almost entirely arising from the electric charge of the valence quarks. The QED effects include both self-energy contributions and interactions between the valence quarks/anti-quarks. By combining results from different signs of the valence quark electric charge we are able to isolate the interaction term which is dominated by the Coulomb piece, $\langle α_{\mathrm{QED}}e_{q_1}e_{\overline{q}_2}/r \rangle$, in the nonrelativistic limit. We study this for $D_s$, $η_c$ and $J/ψ$ mesons, working in lattice QCD plus quenched QED. We use gluon field configurations that include up, down, strange and charm quarks in the sea at multiple values of the lattice spacing. Our results, including also values for mesons with quarks heavier than charm, can be used to improve phenomenological models for the QED contributions. The QED interaction term carries information about meson structure; we derive effective sizes $\langle 1/r_{\mathrm{eff}} \rangle^{-1}$ for $η_c$, $J/ψ$ and $D_s$ of 0.206(8) fm, 0.321(14) fm and 0.307(31) fm respectively.
description: 8 pages, 3 figures
Genetic characterisation of the evolution of a novel metabolic function in yeast
Creators: name: Pérez-Bercoff, Åsa
name: Russell, Tonia
name: Attfield, Paul
name: Bell, Philip
name: Edwards, Richard
Publisher: name: F1000Research
Year: 2015

description: We have a unique opportunity to study how new biological pathways have evolved to produce a yeast with a novel metabolic activity. Thirty-seven Saccharomyces cerevisiae strains were grown as a mixed population, and adapted on a specific media for 1463 days, undergoing sexual mating every two months. As a pilot study, three of the ancestral strains from the starting population, including two diploids, were selected for new PacBio RSII long-read single molecule real time (SMRT) sequencing at the Ramaciotti Centre for Genomics. High quality complete genomes were assembled de novo using the hierarchical genome-assembly process (HGAP3) using only PacBio non-hybrid long-read SMRT sequencing data, and corrected using Quiver. In addition, we have shotgun metagenomic Illumina data from a population exhibiting early adaptation to growth on the selective media. We are developing methods to map these short-read data onto several high quality ancestral genomes in order to estimate the relative contribution of each ancestor's genetic variation to the evolved population, and identify possible sites of recombination. In addition, metagenomic data is being mapped against the official S. cerevisiae reference strain S288c to conduct variant calling to identify single nucleotide polymorphisms (SNPs) that are not present in any of our ancestral or reference genomes. These will be compared to the publicly available "100 yeast genomes", and partitioned into natural variation and candidates for novel mutations. By doing these comparisons we hope to elucidate how the population has evolved to acquire its novel characteristics.
Forecasting El Niño - Southern Oscillation (ENSO) events : a neural network approach
Creators: name: Tangang, Fredolin T.
Publisher: name: University of British Columbia
Year: 2009

description: Neural network models were used to seasonally forecast the tropical Pacific sea surface temperature anomalies (SSTA) in the Nino 3.4 region (6°S - 6°N, 120°W - 170°W). The inputs to the neural networks (i.e. the predictors) were the first seven wind stress empirical orthogonal function (EOF) modes of the tropical Pacific (20°S - 20°N, 120°E - 70°W) for four seasons and the Nino 3.4 SSTA persistence for the final season. The period 1952-1981 was used for training the neural network models, and the period 1982-1992 for forecast validation. At 6-month lead time, neural networks attained forecast skills comparable to the other El Nino - Southern Oscillation (ENSO) models. The results suggested that neural network models were viable for ENSO forecasting even at longer lead times of 9 to 12 months. It appeared that at these longer leads, the underlying relationship between the wind stress and Nino 3.4 SSTA became increasingly nonlinear. Two types of neural network models were further compared for forecasting the SSTA over several standard equatorial Pacific regions (Nino 3, 3.4, 3.5, 4, P2, P4 and P5). The first type used the sea level pressure (SLP) as predictor, while the second one used the wind stress. By ensemble averaging over 20 forecasts with random initial weights, the resulting forecasts were much less noisy than those in the earlier models. The wind stress models had better forecast skill at short lead times, while the SLP models generally had better skill at lead times of 6 months or longer. The western-central regions of the equatorial Pacific Ocean were best forecasted, with the Nino 4 region (6°S - 6°N, 160°E - 150°W) having the highest skiU, foUowed by Nino 3.4 and 3.5 (10°S - 6°N, 120°W - 180°), then Nino 3 (6°S - 6°N, 90° W - 150°W). The eastern boundary regions P4 (0 - 10°N, 80°W - 100°W) and P5 (10°S - 0, 80°W - 100° W) had much lower skill, while the western boundary region P2 (10°S - 10°N, 140°E - 180°) had no forecast skill. In an attempt to understand the inner working of the models, smaller networks were constructed with the extended empirical orthogonal functions (EEOF) of the SLP field as inputs. These smaller networks delivered forecasting skills similar to those of earlier models. By network pruning and spectral analyses, four important inputs were identified: modes 1, 2 and 6 of the SLP EEOFs and the SSTA persistence. Mode 1 characterized the low frequency oscillation (LFO, with 4 - 5 years period), and was interpreted as the typical ENSO signal, while mode 2, with a period of 2 - 5 years, appeared to characterize the quasi-biennial oscillation (QBO) plus the LFO. Mode 6 was dominated by decadal and interdecadal variations. Thus, forecasting ENSO seems to require information from the QBO, and the decadal-interdecadal oscillations. The nonlinearity of the networks tended to increase with lead time, and to become stronger for the eastern regions of the equatorial Pacific Ocean.
СТАТУС НОВОРОЖДЕННЫХ С ПЕРИНАТАЛЬНЫМ ПОРАЖЕНИЕМ ЦЕНТРАЛЬНОЙ НЕРВНОЙ СИСТЕМЫ
Creators: name: Усманова, Мунира
Publisher: name: Zenodo
Year: 2024

description: В статье приведены данные о 50 новорожденных, с гипоксическим поражением ЦНС в неонатальном периоде госпитализированных и амбулаторно лечившихся в отделении неонотологии областного детского многопрофильного медицинского г. Самарканда с 2021 по 2022 год. Всем обследуемым новорожденным и их матерям проведена оценка акушерского анамнеза, пери-  и постнатального периода развития детей.  Проводилась оценка физического развития, ЦНС, и клинического статуса, включавшего данные объективного осмотра.
Detecting the quantum zero-point motion of vortices in the cuprate superconductors
Creators: name: Bartosch, Lorenz
name: Balents, Leon
name: Sachdev, Subir
Publisher: name: arXiv
Year: 2006
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We explore the experimental implications of a recent theory of the quantum dynamics of vortices in two-dimensional superfluids proximate to Mott insulators. The theory predicts modulations in the local density of states in the regions over which the vortices execute their quantum zero point motion. We use the spatial extent of such modulations in scanning tunnelling microscopy measurements on the vortex lattice of BSCCO to estimate the inertial mass of a point vortex. We discuss other, more direct, experimental signatures of the vortex dynamics.
description: 24 pages, 5 figures; expanded version of cond-mat/0502002, with details of calculations
Unconventional superparamagnetic behavior in the modified cubic spinel compound LiNi$_{0.5}$Mn$_{1.5}$O$_{4}$
Creators: name: Islam, S. S.
name: Singh, Vikram
name: Somesh, K
name: Mukharjee, Prashanta K
name: Jain, A.
name: Yusuf, S. M.
name: Nath, R.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Structural, electronic, and magnetic properties of modified cubic spinel compound LiNi$_{0.5}$Mn$_{1.5}$O$_{4}$ are studied via x-ray diffraction, resistivity, DC and AC magnetization, heat capacity, neutron diffraction, $^7$Li nuclear magnetic resonance, magnetocaloric effect, magnetic relaxation, and magnetic memory effect experiments. We stabilized this compound in a cubic structure with space group $P4_{3}32$. It exhibits semiconducting character with an electronic band gap of $Δ/k_{\rm B} \simeq 0.4$ eV. The interaction within each Mn$^{4+}$ and Ni$^{2+}$ sub-lattice and between Mn$^{4+}$ and Ni$^{2+}$ sublattices is found to be ferromagnetic (FM) and antiferromagnetic (AFM), respectively which leads to the onset of a ferrimagnetic transition at $T_{\rm C} \simeq 125$~K. The reduced values of frustration parameter ($f$) and ordered moments reflect magnetic frustration due to competing FM and AFM interactions. From the $^7$Li NMR shift vs susceptibility plot, the average hyperfine coupling between $^7$Li nuclei and Ni$^{2+}$ and Mn$^{4+}$ spins is calculated to be $\sim 672.4$~Oe/$μ_{\rm B}$. A detailed critical behaviour study is done in the vicinity of $T_{\rm C}$ using modified-Arrott plot, Kouvel-Fisher plot, and universal scaling of magnetization isotherms. The estimated critical exponents correspond to the 3D XY universality class. A large magneto-caloric effect is observed with a maximum isothermal change in entropy $ΔS_m \simeq - 11.3$~J/Kg-K and a maximum relative cooling power $RCP \simeq 604$~J/Kg for 9~T magnetic field change. The imaginary part of the AC susceptibility depicts a strong frequency dependent hump at $T=T_{\rm f2}$ well below the blocking temperature $T_{\rm b}\simeq120$~K. The Arrhenius behaviour of frequency dependent $T_{\rm f2}$ and the absence of ZFC memory confirm the existence of superparamagnetism in the ferrimagnetically ordered state.
description: 23 pages, 22 figures, and 4 tables; Phys. Rev. B (Accepted)
Geometric Scaling from GLAP evolution
Creators: name: Caola, Fabrizio
name: Forte, Stefano
Publisher: name: arXiv
Year: 2008
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We show that the geometric scaling of the total virtual photon-proton cross section data can be explained using standard linear GLAP perturbative evolution with generic boundary conditions in a wide kinematic region. This allows us to single out the region where geometric scaling may provide evidence for parton saturation.
description: Final version, published in Phys. Rev. Letters. References and minor clarifications added. 4 pages, 5 figures, LaTeX with REVTeX
The impact of stress urinary incontinence on sexual function in a Malaysian population
Creators: name: Renly Lim
name: Liong Men Long
name: Nurzalina, Abdul Karim Khan
name: Hay, Yuen Kah
Publisher: name: F1000Research
Year: 2015

description: A growing body of evidence highlighted the paradigm of interdependence between male and female sexual function as a disorder of a couple. We prospectively evaluated the effect of stress urinary incontinence (SUI) on sexual function of female patients and their respective partners. Our findings suggest that SUI negatively affects the sexual function of both patients and their partners.