Can electronic search engines optimize screening of search results in systematic reviews: an empirical study.

Science.gov (United States)

Sampson, Margaret; Barrowman, Nicholas J; Moher, David; Clifford, Tammy J; Platt, Robert W; Morrison, Andra; Klassen, Terry P; Zhang, Li

2006-02-24

Most electronic search efforts directed at identifying primary studies for inclusion in systematic reviews rely on the optimal Boolean search features of search interfaces such as DIALOG and Ovid. Our objective is to test the ability of an Ultraseek search engine to rank MEDLINE records of the included studies of Cochrane reviews within the top half of all the records retrieved by the Boolean MEDLINE search used by the reviewers. Collections were created using the MEDLINE bibliographic records of included and excluded studies listed in the review and all records retrieved by the MEDLINE search. Records were converted to individual HTML files. Collections of records were indexed and searched through a statistical search engine, Ultraseek, using review-specific search terms. Our data sources, systematic reviews published in the Cochrane library, were included if they reported using at least one phase of the Cochrane Highly Sensitive Search Strategy (HSSS), provided citations for both included and excluded studies and conducted a meta-analysis using a binary outcome measure. Reviews were selected if they yielded between 1000-6000 records when the MEDLINE search strategy was replicated. Nine Cochrane reviews were included. Included studies within the Cochrane reviews were found within the first 500 retrieved studies more often than would be expected by chance. Across all reviews, recall of included studies into the top 500 was 0.70. There was no statistically significant difference in ranking when comparing included studies with just the subset of excluded studies listed as excluded in the published review. The relevance ranking provided by the search engine was better than expected by chance and shows promise for the preliminary evaluation of large results from Boolean searches. A statistical search engine does not appear to be able to make fine discriminations concerning the relevance of bibliographic records that have been pre-screened by systematic reviewers.

Self-regulation during job search: the opposing effects of employment self-efficacy and job search behavior self-efficacy.

Science.gov (United States)

Liu, Songqi; Wang, Mo; Liao, Hui; Shi, Junqi

2014-11-01

Adopting a self-regulatory perspective, the current study examined the within-person relationships among job search cognitions, job search behaviors, and job search success (i.e., number of job offers received). Specifically, conceptualizing job search behaviors as guided by a hierarchy of means-end (i.e., job search behavior-employment) goal structure, we differentiated employment self-efficacy from job search behavior self-efficacy. Our results showed that higher levels of perceived job search progress could lead to more frequent job search behaviors through enhancing job search behavior self-efficacy. However, higher levels of perceived job search progress could also lead to less frequent job search behaviors through elevating employment self-efficacy. In addition, the relationships between perceived job search progress and efficacy beliefs were moderated by job seekers' level of internal attribution of their progress. Finally, we found that at the within-person level, frequency of job search behaviors was positively related to number of job offers received. These findings were discussed in terms of their theoretical and practical implications. (PsycINFO Database Record (c) 2014 APA, all rights reserved).

X(3872) and the search for its bottomonium counterpart at the LHC

CERN Document Server

Toms, Konstantin; The ATLAS collaboration

2016-01-01

X(3872) history and theoretical status overview. ATLAS study of the ψ(2S) and X(3872) production. Search for X(3872) bottomonium counterpart by ATLAS. Search for Xb at CMS. Determination of X(3872) quantum numbers at LHCb.

Heuristic Search Theory and Applications

CERN Document Server

Edelkamp, Stefan

2011-01-01

Search has been vital to artificial intelligence from the very beginning as a core technique in problem solving. The authors present a thorough overview of heuristic search with a balance of discussion between theoretical analysis and efficient implementation and application to real-world problems. Current developments in search such as pattern databases and search with efficient use of external memory and parallel processing units on main boards and graphics cards are detailed. Heuristic search as a problem solving tool is demonstrated in applications for puzzle solving, game playing, constra

The Weaknesses of Full-Text Searching

Science.gov (United States)

Beall, Jeffrey

2008-01-01

This paper provides a theoretical critique of the deficiencies of full-text searching in academic library databases. Because full-text searching relies on matching words in a search query with words in online resources, it is an inefficient method of finding information in a database. This matching fails to retrieve synonyms, and it also retrieves…

Production of electroweak bosons at hadron colliders: theoretical aspects

CERN Document Server

Mangano, Michelangelo L.

2016-01-01

Since the W and Z discovery, hadron colliders have provided a fertile ground, in which continuously improving measurements and theoretical predictions allow to precisely determine the gauge boson properties, and to probe the dynamics of electroweak and strong interactions. This article will review, from a theoretical perspective, the role played by the study, at hadron colliders, of electroweak boson production properties, from the better understanding of the proton structure, to the discovery and studies of the top quark and of the Higgs, to the searches for new phenomena beyond the Standard Model.

FEELINGS OF INSECURITY IN CONTEXT: THEORETICAL PERSPECTIVES FOR STUDYING FEAR OF CRIME IN LATE LIFE

Directory of Open Access Journals (Sweden)

Liesbeth De Donder

2009-01-01

Full Text Available This paper broadens theoretical perspectives on fear of crime in late life by exploring the concept against the backdrop of a changing society. Since the emergence of the first studies that address fear of crime in late life, research overemphasizes the search for related independent variables being heedless of a thorough theoretical framework. Recent researchers, however, perceive the construct of ‘fear of crime’ as an ‘umbrella’ concept, which encompasses crime related fear and more diffuse ‘feelings of insecurity’. In response to a lack of macro-theorizing, this article illuminates some of the most important characteristics and descriptions of contemporary societies that are relevant to fear of crime. It is shown that in relation to fear of crime, the macro-level of society can be conceptualized as having four important ambivalences. In conclusion, the article

Theoretical studies of chemical reaction dynamics

Energy Technology Data Exchange (ETDEWEB)

Schatz, G.C. [Argonne National Laboratory, IL (United States)

1993-12-01

This collaborative program with the Theoretical Chemistry Group at Argonne involves theoretical studies of gas phase chemical reactions and related energy transfer and photodissociation processes. Many of the reactions studied are of direct relevance to combustion; others are selected they provide important examples of special dynamical processes, or are of relevance to experimental measurements. Both classical trajectory and quantum reactive scattering methods are used for these studies, and the types of information determined range from thermal rate constants to state to state differential cross sections.

A study of Consistency in the Selection of Search Terms and Search Concepts: A Case Study in National Taiwan University

Directory of Open Access Journals (Sweden)

Mu-hsuan Huang

2001-12-01

Full Text Available This article analyzes the consistency in the selection of search terms and search contents of college and graduate students in National Taiwan University when they are using PsycLIT CD-ROM database. 31 students conducted pre-assigned searches, doing 59 searches generating 609 search terms. The study finds the consistency in selection of search terms of first level is 22.14% and second level is 35%. These results are similar with others’ researches. About the consistency in search concepts, no matter the overlaps of searched articles or judge relevant articles are lower than other researches. [Article content in Chinese

The use of grounded theory in studies of nurses and midwives' coping processes: a systematic literature search.

Science.gov (United States)

Cheer, Karen; MacLaren, David; Tsey, Komla

2015-01-01

Researchers are increasingly using grounded theory methodologies to study the professional experience of nurses and midwives. To review common grounded theory characteristics and research design quality as described in grounded theory studies of coping strategies used by nurses and midwives. A systematic database search for 2005-2015 identified and assessed grounded theory characteristics from 16 studies. Study quality was assessed using a modified Critical Appraisal Skills Programme tool. Grounded theory was considered a methodology or a set of methods, able to be used within different nursing and midwifery contexts. Specific research requirements determined the common grounded theory characteristics used in different studies. Most researchers did not clarify their epistemological and theoretical perspectives. To improve research design and trustworthiness of grounded theory studies in nursing and midwifery, researchers need to state their theoretical stance and clearly articulate their use of grounded theory methodology and characteristics in research reporting.

The effects of savings on reservation wages and search effort

NARCIS (Netherlands)

Lammers, M.

2014-01-01

This paper discusses the interrelations among wealth, reservation wages and search effort. A theoretical job search model predicts wealth to affect reservation wages positively, and search effort negatively. Subsequently, reduced form equations for reservation wages and search intensity take these

Budget constraints and optimization in sponsored search auctions

CERN Document Server

Yang, Yanwu

2013-01-01

The Intelligent Systems Series publishes reference works and handbooks in three core sub-topic areas: Intelligent Automation, Intelligent Transportation Systems, and Intelligent Computing. They include theoretical studies, design methods, and real-world implementations and applications. The series' readership is broad, but focuses on engineering, electronics, and computer science. Budget constraints and optimization in sponsored search auctions takes into account consideration of the entire life cycle of campaigns for researchers and developers working on search systems and ROI maximization

Citation searches are more sensitive than keyword searches to identify studies using specific measurement instruments.

Science.gov (United States)

Linder, Suzanne K; Kamath, Geetanjali R; Pratt, Gregory F; Saraykar, Smita S; Volk, Robert J

2015-04-01

To compare the effectiveness of two search methods in identifying studies that used the Control Preferences Scale (CPS), a health care decision-making instrument commonly used in clinical settings. We searched the literature using two methods: (1) keyword searching using variations of "Control Preferences Scale" and (2) cited reference searching using two seminal CPS publications. We searched three bibliographic databases [PubMed, Scopus, and Web of Science (WOS)] and one full-text database (Google Scholar). We report precision and sensitivity as measures of effectiveness. Keyword searches in bibliographic databases yielded high average precision (90%) but low average sensitivity (16%). PubMed was the most precise, followed closely by Scopus and WOS. The Google Scholar keyword search had low precision (54%) but provided the highest sensitivity (70%). Cited reference searches in all databases yielded moderate sensitivity (45-54%), but precision ranged from 35% to 75% with Scopus being the most precise. Cited reference searches were more sensitive than keyword searches, making it a more comprehensive strategy to identify all studies that use a particular instrument. Keyword searches provide a quick way of finding some but not all relevant articles. Goals, time, and resources should dictate the combination of which methods and databases are used. Copyright © 2015 Elsevier Inc. All rights reserved.

Tau decays: A theoretical perspective

International Nuclear Information System (INIS)

Marciano, W.J.

1992-11-01

Theoretical predictions for various tau decay rates are reviewed. Effects of electroweak radiative corrections are described. Implications for precision tests of the standard model and ''new physics'' searches are discussed. A perspective on the tau decay puzzle and 1-prong problem is given

Methodology, theoretical framework and scholarly significance: An ...

African Journals Online (AJOL)

Methodology, theoretical framework and scholarly significance: An overview ... AFRICAN JOURNALS ONLINE (AJOL) · Journals · Advanced Search ... Keywords: Legal Research, Methodology, Theory, Pedagogy, Legal Training, Scholarship ...

In vitro drug interaction of levocetirizine and diclofenac: Theoretical and spectroscopic studies.

Science.gov (United States)

Abo Dena, Ahmed S; Abdel Gaber, Sara A

2017-06-15

Levocetirizine dihydrochloride is known to interact with some anti-inflammatory drugs. We report here a comprehensive integrated theoretical and experimental study for the in vitro drug interaction between levocetirizine dihydrochloride (LEV) and diclofenac sodium (DIC). The interaction of the two drugs was confirmed by the molecular ion peak obtained from the mass spectrum of the product. Moreover, FTIR and 1 HNMR spectra of the individual drugs and their interaction product were inspected to allocate the possible sites of interaction. In addition, quantum mechanical DFT calculations were performed to search for the interaction sites and to verify the types of interactions deduced from the spectroscopic studies such as charge-transfer and non-bonding π-π interactions. It was found that the studied drugs interact with each other in aqueous solution via four types of interactions, namely, ion-pair formation, three weak hydrogen bonds, non-bonding π-π interactions and charge-transfer from DIC to LEV. Copyright © 2017 Elsevier B.V. All rights reserved.

In vitro drug interaction of levocetirizine and diclofenac: Theoretical and spectroscopic studies

Science.gov (United States)

Abo Dena, Ahmed S.; Abdel Gaber, Sara A.

2017-06-01

Levocetirizine dihydrochloride is known to interact with some anti-inflammatory drugs. We report here a comprehensive integrated theoretical and experimental study for the in vitro drug interaction between levocetirizine dihydrochloride (LEV) and diclofenac sodium (DIC). The interaction of the two drugs was confirmed by the molecular ion peak obtained from the mass spectrum of the product. Moreover, FTIR and 1HNMR spectra of the individual drugs and their interaction product were inspected to allocate the possible sites of interaction. In addition, quantum mechanical DFT calculations were performed to search for the interaction sites and to verify the types of interactions deduced from the spectroscopic studies such as charge-transfer and non-bonding π-π interactions. It was found that the studied drugs interact with each other in aqueous solution via four types of interactions, namely, ion-pair formation, three weak hydrogen bonds, non-bonding π-π interactions and charge-transfer from DIC to LEV.

Methodological studies on the search for Gravitational Waves and Neutrinos from Type II Supernovae

International Nuclear Information System (INIS)

Casentini, Claudio

2016-01-01

Type II SNe, also called Core-collapse SuperNovae have a neutrino (v) emission, as confirmed by SN 1987A, and are also potential sources of gravitational waves. Neutrinos and gravitational waves from these sources reach Earth almost contemporaneously and without relevant interaction with stellar matter and interstellar medium. The upcoming advanced gravitational interferometers would be sensitive enough to detect gravitational waves signals from close galactic Core-collapse SuperNovae events. Nevertheless, significant uncertainties on theoretical models of emission remain. A joint search of coincident low energy neutrinos and gravitational waves events from these sources would bring valuable information from the inner core of the collapsing star and would enhance the detection of the so-called Silent SuperNovae. Recently a project for a joint search involving gravitational wave interferometers and neutrino detectors has started. We discuss the benefits of a joint search and the status of the search project. (paper)

Searching methods for biometric identification systems: Fundamental limits

NARCIS (Netherlands)

Willems, F.M.J.

2009-01-01

We study two-stage search procedures for biometric identification systems in an information-theoretical setting. Our main conclusion is that clustering based on vector-quantization achieves the optimum trade-off between the number of clusters (cluster rate) and the number of individuals within a

Status of gluonium searches

International Nuclear Information System (INIS)

Heusch, C.A.; California Univ., Santa Cruz, CA

1991-01-01

Quantum chromodynamics predicts the existence of quarkless mesons. The search for these hadrons has been ingenious and persevering. A review is presented of the current status of research that considers all model-dependent theoretical prejudice when searching for specific states. Early hints for candidate states have been investigated in the light of recent data, mostly from the Mark III Collaboration, in radiative charmonium decay. No 'smoking-gun' candidate stands out. (R.P.) 25 refs., 20 figs., 2 tabs

Informal Versus Formal Search : Which Yields a Better Pay?

OpenAIRE

Semih Tumen

2015-01-01

Estimates on the effect of job contact method – i.e., informal versus formal search – on wage offers vary considerably across studies, with some of them finding a positive correlation between getting help from informal connections and obtaining high-paying jobs, while others finding a negative one. In this paper, I theoretically investigate the sources of discrepancies in these empirical results. Using a formal job search framework, I derive an equilibrium wage distribution which reveals that...

A comparative study of the A* heuristic search algorithm used to solve efficiently a puzzle game

Science.gov (United States)

Iordan, A. E.

2018-01-01

The puzzle game presented in this paper consists in polyhedra (prisms, pyramids or pyramidal frustums) which can be moved using the free available spaces. The problem requires to be found the minimum number of movements in order the game reaches to a goal configuration starting from an initial configuration. Because the problem is enough complex, the principal difficulty in solving it is given by dimension of search space, that leads to necessity of a heuristic search. The improving of the search method consists into determination of a strong estimation by the heuristic function which will guide the search process to the most promising side of the search tree. The comparative study is realized among Manhattan heuristic and the Hamming heuristic using A* search algorithm implemented in Java. This paper also presents the necessary stages in object oriented development of a software used to solve efficiently this puzzle game. The modelling of the software is achieved through specific UML diagrams representing the phases of analysis, design and implementation, the system thus being described in a clear and practical manner. With the purpose to confirm the theoretical results which demonstrates that Manhattan heuristic is more efficient was used space complexity criterion. The space complexity was measured by the number of generated nodes from the search tree, by the number of the expanded nodes and by the effective branching factor. From the experimental results obtained by using the Manhattan heuristic, improvements were observed regarding space complexity of A* algorithm versus Hamming heuristic.

A Search Model of Discouragement

DEFF Research Database (Denmark)

Rosholm, Michael; Toomet, Ott

Discouragement is a process occurring during an unemployment spell. As the spell prolongs, an individual gradually realises that the returns to search can no longer outweigh search costs, and hence she may eventually leave the labour force. This is analysed theoretically in a framework...... of unemployed search. We construct a search model, which is stationary from the point of view of the individual, but which has nonstationary features. Namely, the unemployed worker is occasionally hit by shocks leading to a decline in job offer arrival rates. These shocks can be due to stigmatisation...... or to psychological consequences of unemployement affecting search effectiveness. This model enables us to analyse the issue of discouragement, as the returns to search will gradually decline. Even so, the model is actually stationary from the point of view of the individual, which implies that many interesting...

Theoretical studies of three triazole derivatives as corrosion inhibitors for mild steel in acidic medium

International Nuclear Information System (INIS)

Guo, Lei; Zhu, Shanhong; Zhang, Shengtao; He, Qiao; Li, Weihua

2014-01-01

Highlights: • Three triazole derivatives as corrosion inhibitors were theoretically investigated. • Quantum chemical calculations and Monte Carlo simulations were performed. • Quantitative structure activity relationship (QSAR) approach has been used. • Theoretical conclusions are validated by the consistency with experimental findings. - Abstract: Corrosion inhibitive performance of 4-chloro-acetophenone-O-1′-(1′.3′.4′-triazolyl)-metheneoxime (CATM), 4-fluoro-acetophenone-O-1′-(1′.3′.4′-triazolyl)-metheneoxime (FATM), and 3,4-dichloro-acetophenone-O-1′-(1′.3′.4′-triazolyl)-metheneoxime (DATM) during the acidic corrosion of mild steel surface was investigated using density functional theory (DFT). Quantum chemical parameters such as the highest occupied molecular orbital energy (E HOMO ), the lowest unoccupied molecular orbital energy (E LUMO ), energy gap (ΔE), Mulliken charges, hardness (ξ), dipole moment (μ), and the fraction of electrons transferred (ΔN), were calculated. Quantitative structure activity relationship (QSAR) approach has been used, and a composite index of above-mentioned descriptors was performed to characterize the inhibition performance of the studied molecules. Furthermore, Monte Carlo simulation studies were applied to search for the best configurational space of iron/triazole derivative system

Theoretical Studies of Hydrogen Storage Alloys.

Energy Technology Data Exchange (ETDEWEB)

Jonsson, Hannes

2012-03-22

Theoretical calculations were carried out to search for lightweight alloys that can be used to reversibly store hydrogen in mobile applications, such as automobiles. Our primary focus was on magnesium based alloys. While MgH{sub 2} is in many respects a promising hydrogen storage material, there are two serious problems which need to be solved in order to make it useful: (i) the binding energy of the hydrogen atoms in the hydride is too large, causing the release temperature to be too high, and (ii) the diffusion of hydrogen through the hydride is so slow that loading of hydrogen into the metal takes much too long. In the first year of the project, we found that the addition of ca. 15% of aluminum decreases the binding energy to the hydrogen to the target value of 0.25 eV which corresponds to release of 1 bar hydrogen gas at 100 degrees C. Also, the addition of ca. 15% of transition metal atoms, such as Ti or V, reduces the formation energy of interstitial H-atoms making the diffusion of H-atoms through the hydride more than ten orders of magnitude faster at room temperature. In the second year of the project, several calculations of alloys of magnesium with various other transition metals were carried out and systematic trends in stability, hydrogen binding energy and diffusivity established. Some calculations of ternary alloys and their hydrides were also carried out, for example of Mg{sub 6}AlTiH{sub 16}. It was found that the binding energy reduction due to the addition of aluminum and increased diffusivity due to the addition of a transition metal are both effective at the same time. This material would in principle work well for hydrogen storage but it is, unfortunately, unstable with respect to phase separation. A search was made for a ternary alloy of this type where both the alloy and the corresponding hydride are stable. Promising results were obtained by including Zn in the alloy.

Protein search for multiple targets on DNA

Energy Technology Data Exchange (ETDEWEB)

Lange, Martin [Johannes Gutenberg University, Mainz 55122 (Germany); Department of Chemistry, Rice University, Houston, Texas 77005 (United States); Kochugaeva, Maria [Department of Chemistry, Rice University, Houston, Texas 77005 (United States); Kolomeisky, Anatoly B., E-mail: tolya@rice.edu [Department of Chemistry, Rice University, Houston, Texas 77005 (United States); Center for Theoretical Biological Physics, Rice University, Houston, Texas 77005 (United States)

2015-09-14

Protein-DNA interactions are crucial for all biological processes. One of the most important fundamental aspects of these interactions is the process of protein searching and recognizing specific binding sites on DNA. A large number of experimental and theoretical investigations have been devoted to uncovering the molecular description of these phenomena, but many aspects of the mechanisms of protein search for the targets on DNA remain not well understood. One of the most intriguing problems is the role of multiple targets in protein search dynamics. Using a recently developed theoretical framework we analyze this question in detail. Our method is based on a discrete-state stochastic approach that takes into account most relevant physical-chemical processes and leads to fully analytical description of all dynamic properties. Specifically, systems with two and three targets have been explicitly investigated. It is found that multiple targets in most cases accelerate the search in comparison with a single target situation. However, the acceleration is not always proportional to the number of targets. Surprisingly, there are even situations when it takes longer to find one of the multiple targets in comparison with the single target. It depends on the spatial position of the targets, distances between them, average scanning lengths of protein molecules on DNA, and the total DNA lengths. Physical-chemical explanations of observed results are presented. Our predictions are compared with experimental observations as well as with results from a continuum theory for the protein search. Extensive Monte Carlo computer simulations fully support our theoretical calculations.

Theoretical Semi-Empirical AM1 studies of Schiff Bases

International Nuclear Information System (INIS)

Arora, K.; Burman, K.

2005-01-01

The present communication reports the theoretical semi-empirical studies of schiff bases of 2-amino pyridine along with their comparison with their parent compounds. Theoretical studies reveal that it is the azomethine group, in the schiff bases under study, that acts as site for coordination to metals as it is reported by many coordination chemists. (author)

Exercise and Early-Onset Alzheimer’s Disease: Theoretical Considerations

Directory of Open Access Journals (Sweden)

Astrid M. Hooghiemstra

2012-04-01

Full Text Available Background/Aims: Although studies show a negative relationship between physical activity and the risk for cognitive impairment and late-onset Alzheimer’s disease, studies concerning early-onset Alzheimer’s disease (EOAD are lacking. This review aims to justify the value of exercise interventions in EOAD by providing theoretical considerations that include neurobiological processes. Methods: A literature search on key words related to early-onset dementia, exercise, imaging, neurobiological mechanisms, and cognitive reserve was performed. Results/Conclusion: Brain regions and neurobiological processes contributing to the positive effects of exercise are affected in EOAD and, thus, provide theoretical support for exercise interventions in EOAD. Finally, we present the design of a randomized controlled trial currently being conducted in early-onset dementia patients.

Multi-agent search for source localization in a turbulent medium

International Nuclear Information System (INIS)

Hajieghrary, Hadi; Hsieh, M. Ani; Schwartz, Ira B.

2016-01-01

We extend the gradient-less search strategy referred to as “infotaxis” to a distributed multi-agent system. “Infotaxis” is a search strategy that uses sporadic sensor measurements to determine the source location of materials dispersed in a turbulent medium. In this work, we leverage the spatio-temporal sensing capabilities of a mobile sensing agents to optimize the time spent finding and localizing the position of the source using a multi-agent collaborative search strategy. Our results suggest that the proposed multi-agent collaborative search strategy leverages the team's ability to obtain simultaneous measurements at different locations to speed up the search process. We present a multi-agent collaborative “infotaxis” strategy that uses the relative entropy of the system to synthesize a suitable search strategy for the team. The result is a collaborative information theoretic search strategy that results in control actions that maximize the information gained by the team, and improves estimates of the source position. - Highlights: • We extend the gradient-less infotaxis search strategy to a distributed multi-agent system. • Leveraging the spatio-temporal sensing capabilities of a team of mobile sensing agents speeds up the search process. • The resulting information theoretic search strategy maximizes the information gained and improves the estimate of the source position.

THE ALGORITHM AND PROGRAM OF M-MATRICES SEARCH AND STUDY

Directory of Open Access Journals (Sweden)

Y. N. Balonin

2013-05-01

Full Text Available The algorithm and software for search and study of orthogonal bases matrices – minimax matrices (M-matrix are considered. The algorithm scheme is shown, comments on calculation blocks are given, and interface of the MMatrix software system developed with participation of the authors is explained. The results of the universal algorithm work are presented as Hadamard matrices, Belevitch matrices (C-matrices, conference matrices and matrices of even and odd orders complementary and closely related to those ones by their properties, in particular, the matrix of the 22-th order for which there is no C-matrix. Examples of portraits for alternative matrices of the 255-th and the 257-th orders are given corresponding to the sequences of Mersenne and Fermat numbers. A new way to get Hadamard matrices is explained, different from the previously known procedures based on iterative processes and calculations of Lagrange symbols, with theoretical and practical meaning.

Smart Companies, Inspiring the Future: A Theoretical Review

OpenAIRE

Echazarreta Soler, Carmen; Costa Marcé, Albert

2017-01-01

The economic and financial global crises have accelerated the search for alternative business models. The aim of this article is to describe the main characteristics of smart companies capable of overcoming the shortcomings of the current economic system. After conducting a theoretical review of the main studies related to this area, we conclude that there is a need for smart companies championed by leaders who promote the use of information technologies and communication as means...

Knowledge base, information search and intention to adopt innovation

NARCIS (Netherlands)

Rijnsoever, van F.J.; Castaldi, C.

2008-01-01

Innovation is a process that involves searching for new information. This paper builds upon theoretical insights on individual and organizational learning and proposes a knowledge based model of how actors search for information when confronted with innovation. The model takes into account different

Spectroscopic and theoretical study of the o-vanillin hydrazone of the mycobactericidal drug isoniazid

Science.gov (United States)

González-Baró, Ana C.; Pis-Diez, Reinaldo; Parajón-Costa, Beatriz S.; Rey, Nicolás A.

2012-01-01

A complete and detailed study of the hydrazone obtained from condensation of antituberculous isoniazid (hydrazide of the isonicotinic acid, INH) and o-vanillin (2-hydroxy-3-methoxybenzaldehyde, o-HVa) is performed. It includes structural and spectroscopic analyses, comparing experimental and theoretical results. The compound was obtained as a chloride of the pyridinic salt (INHOVA +Cl -) but it will be referred as INHOVA for the sake of simplicity. The conformational space was searched and optimized geometries were determined both in gas phase and including solvent effects. Vibrational (IR and Raman), electronic and NMR spectra were registered and assigned with the help of computational methods based on the Density Functional Theory. Isoniazid hydrazones are good candidates for therapeutic agents against tuberculosis with conserved efficiency and lower toxicity and resistance than parent INH.

A combined experimental and theoretical study

Indian Academy of Sciences (India)

A combined theoretical and experimental study was also performed, which demonstrated that the clus- ters 1–3 with ... silica gel TLC plates (MERCK TLC Plates). The NMR .... tronic μ3-Se and maintains the same number of clus- ter valance ...

Two-agent cooperative search using game models with endurance-time constraints

Science.gov (United States)

Sujit, P. B.; Ghose, Debasish

2010-07-01

In this article, the problem of two Unmanned Aerial Vehicles (UAVs) cooperatively searching an unknown region is addressed. The search region is discretized into hexagonal cells and each cell is assumed to possess an uncertainty value. The UAVs have to cooperatively search these cells taking limited endurance, sensor and communication range constraints into account. Due to limited endurance, the UAVs need to return to the base station for refuelling and also need to select a base station when multiple base stations are present. This article proposes a route planning algorithm that takes endurance time constraints into account and uses game theoretical strategies to reduce the uncertainty. The route planning algorithm selects only those cells that ensure the agent will return to any one of the available bases. A set of paths are formed using these cells which the game theoretical strategies use to select a path that yields maximum uncertainty reduction. We explore non-cooperative Nash, cooperative and security strategies from game theory to enhance the search effectiveness. Monte-Carlo simulations are carried out which show the superiority of the game theoretical strategies over greedy strategy for different look ahead step length paths. Within the game theoretical strategies, non-cooperative Nash and cooperative strategy perform similarly in an ideal case, but Nash strategy performs better than the cooperative strategy when the perceived information is different. We also propose a heuristic based on partitioning of the search space into sectors to reduce computational overhead without performance degradation.

Cuckoo search and firefly algorithm theory and applications

CERN Document Server

2014-01-01

Nature-inspired algorithms such as cuckoo search and firefly algorithm have become popular and widely used in recent years in many applications. These algorithms are flexible, efficient and easy to implement. New progress has been made in the last few years, and it is timely to summarize the latest developments of cuckoo search and firefly algorithm and their diverse applications. This book will review both theoretical studies and applications with detailed algorithm analysis, implementation and case studies so that readers can benefit most from this book.  Application topics are contributed by many leading experts in the field. Topics include cuckoo search, firefly algorithm, algorithm analysis, feature selection, image processing, travelling salesman problem, neural network, GPU optimization, scheduling, queuing, multi-objective manufacturing optimization, semantic web service, shape optimization, and others.   This book can serve as an ideal reference for both graduates and researchers in computer scienc...

In search of meaningfulness: nostalgia as an antidote to boredom.

Science.gov (United States)

van Tilburg, Wijnand A P; Igou, Eric R; Sedikides, Constantine

2013-06-01

We formulated, tested, and supported, in 6 studies, a theoretical model according to which individuals use nostalgia as a way to reinject meaningfulness in their lives when they experience boredom. Studies 1-3 established that induced boredom causes increases in nostalgia when participants have the opportunity to revert to their past. Studies 4 and 5 examined search for meaning as a mediator of the effect of boredom on nostalgia. Specifically, Study 4 showed that search for meaning mediates the effect of state boredom on nostalgic memory content, whereas Study 5 demonstrated that search for meaning mediates the effect of dispositional boredom on dispositional nostalgia. Finally, Study 6 examined the meaning reestablishment potential of nostalgia during boredom: Nostalgia mediates the effect of boredom on sense of meaningfulness and presence of meaning in one's life. Nostalgia counteracts the meaninglessness that individuals experience when they are bored.

The search for charm, beauty, and truth at high energies. Vol. 16

International Nuclear Information System (INIS)

Bellini, G.; Ting, S.C.C.

1984-01-01

This book examines present experimental knowledge on branching ratios, lifetimes, cross sections, and production mechanisms of charm and heavy flavors. The bases of the theoretical ideas and predictions, and such experimental methods as triggers, techniques, and devices are discussed. Topics covered include the search for charm and beauty with e + e - beams, the search for charm and beauty at Fermilab, the search for charm with bubble chambers, the use of visual detectors in the search for charm and other flavors, lifetime measurements, live targets for lifetime measurements, production cross sections of charm and new flavors, high resolution vertex detectors to search for charm and other flavors, the search for heavy flavors, and special triggers to search for charm and heavy flavors. The contributors participated in the Europhysics Study Conference on High-Energy Physics held in Italy in 1981

[The practice of systematic reviews. II. Searching and selection of studies

DEFF Research Database (Denmark)

Assendelft, W J; van Tulder, M W; Scholten, R J

1999-01-01

can be performed in trial registers and printed indexes and by correspondence with experts and hand searching of journals. Storage of the search results in a bibliographic database is recommended. Various methodological problems may play a role in searching and selecting studies for a review: studies......Structured searching and selection of studies is an important component of a systematic review. It is recommended to record the various steps in a protocol in advance. The thoroughness of the searching and selection will partially depend on the available resources, like manpower and funds. A search...... action should be based on an unequivocally formulated research or clinical question, that is operationalized into clear inclusion and exclusion criteria. The actual start of a search strategy is a search in preferably multiple databases like Medline and EMBASE-Excerpta Medica. Additional search actions...

Greedy Local Search and Vertex Cover in Sparse Random Graphs

DEFF Research Database (Denmark)

Witt, Carsten

2009-01-01

. This work starts with a rigorous explanation for this claim based on the refined analysis of the Karp-Sipser algorithm by Aronson et al. Subsequently, theoretical supplements are given to experimental studies of search heuristics on random graphs. For c 1, a greedy and randomized local-search heuristic...... finds an optimal cover in polynomial time with a probability arbitrarily close to 1. This behavior relies on the absence of a giant component. As an additional insight into the randomized search, it is shown that the heuristic fails badly also on graphs consisting of a single tree component of maximum......Recently, various randomized search heuristics have been studied for the solution of the minimum vertex cover problem, in particular for sparse random instances according to the G(n, c/n) model, where c > 0 is a constant. Methods from statistical physics suggest that the problem is easy if c

Diffusion in liquids a theoretical and experimental study

CERN Document Server

Tyrrell, H J V

1984-01-01

Diffusion in Liquids: A Theoretical and Experimental Study aims to discuss the principles, applications, and advances in the field of diffusion, thermal diffusion, and thermal conduction in liquid systems. The book covers topics such as the principles of non-equilibrium thermodynamics; diffusion in binary and multicompetent systems; and experimental methods of studying diffusion processes in liquids. Also covered in the book are topics such as the theoretical interpretations of diffusion coefficients; hydrodynamic and kinetic theories; and diffusion in electrolyte systems. The text is recommen

Information retrieval for children based on the aggregated search paradigm

NARCIS (Netherlands)

Duarte Torres, Sergio

This report presents research to develop information services for children by expanding and adapting current Information retrieval technologies according to the search characteristics and needs of children. Concretely, we will employ the aggregated search paradigm as theoretical framework. The

Mathematical programming solver based on local search

CERN Document Server

Gardi, Frédéric; Darlay, Julien; Estellon, Bertrand; Megel, Romain

2014-01-01

This book covers local search for combinatorial optimization and its extension to mixed-variable optimization. Although not yet understood from the theoretical point of view, local search is the paradigm of choice for tackling large-scale real-life optimization problems. Today's end-users demand interactivity with decision support systems. For optimization software, this means obtaining good-quality solutions quickly. Fast iterative improvement methods, like local search, are suited to satisfying such needs. Here the authors show local search in a new light, in particular presenting a new kind of mathematical programming solver, namely LocalSolver, based on neighborhood search. First, an iconoclast methodology is presented to design and engineer local search algorithms. The authors' concern about industrializing local search approaches is of particular interest for practitioners. This methodology is applied to solve two industrial problems with high economic stakes. Software based on local search induces ex...

Top partners searches and composite Higgs models

International Nuclear Information System (INIS)

Matsedonskyi, Oleksii; Panico, Giuliano; Wulzer, Andrea

2016-01-01

Colored fermionic partners of the top quark are well-known signatures of the Composite Higgs scenario and for this reason they have been and will be subject of an intensive experimental study at the LHC. Performing an assessment of the theoretical implications of this experimental effort is the goal of the present paper. We proceed by analyzing a set of simple benchmark models, characterized by simple two-dimensional parameter spaces where the results of the searches are conveniently visualized and their impact quantified. We only draw exclusion contours, in the hypothesis of no signal, but of course our formalism could equally well be used to report discoveries in a theoretically useful format.

Validation of search filters for identifying pediatric studies in PubMed.

Science.gov (United States)

Leclercq, Edith; Leeflang, Mariska M G; van Dalen, Elvira C; Kremer, Leontien C M

2013-03-01

To identify and validate PubMed search filters for retrieving studies including children and to develop a new pediatric search filter for PubMed. We developed 2 different datasets of studies to evaluate the performance of the identified pediatric search filters, expressed in terms of sensitivity, precision, specificity, accuracy, and number needed to read (NNR). An optimal search filter will have a high sensitivity and high precision with a low NNR. In addition to the PubMed Limits: All Child: 0-18 years filter (in May 2012 renamed to PubMed Filter Child: 0-18 years), 6 search filters for identifying studies including children were identified: 3 developed by Kastner et al, 1 developed by BestBets, one by the Child Health Field, and 1 by the Cochrane Childhood Cancer Group. Three search filters (Cochrane Childhood Cancer Group, Child Health Field, and BestBets) had the highest sensitivity (99.3%, 99.5%, and 99.3%, respectively) but a lower precision (64.5%, 68.4%, and 66.6% respectively) compared with the other search filters. Two Kastner search filters had a high precision (93.0% and 93.7%, respectively) but a low sensitivity (58.5% and 44.8%, respectively). They failed to identify many pediatric studies in our datasets. The search terms responsible for false-positive results in the reference dataset were determined. With these data, we developed a new search filter for identifying studies with children in PubMed with an optimal sensitivity (99.5%) and precision (69.0%). Search filters to identify studies including children either have a low sensitivity or a low precision with a high NNR. A new pediatric search filter with a high sensitivity and a low NNR has been developed. Copyright © 2013 Mosby, Inc. All rights reserved.

Concluding theoretical remarks

International Nuclear Information System (INIS)

Ellis, J.

1986-01-01

My task in this talk is to review the happenings of this workshop from a theoretical perspective, and to emphasize lines for possible future research. My remarks are organized into a theoretical overview of the what, why, (mainly the hierarchy problem) how, (supersymmetry must be broken: softly or spontaneously, and if the latter, by means of a new U tilde(1) gauge group or through the chiral superfields) when (how heavy are supersymmetric partner particles in different types of theories) and where (can one find evidence for) supersymmetry. In the last part are discussed various ongoing and future searches for photinos γ tilde, gravitinos G tilde, the U vector boson, shiggses H tilde, squarks q tilde and sleptons l tilde, gluinos g tilde, winos W tilde and other gauginos, as well as hunts for indirect effects of supersymmetry, such as for example in baryon decay. Finally there is a little message of encouragement to our experimental colleagues, based on historical precedent. (orig.)

Surfactants, interfaces and pores : a theoretical study

NARCIS (Netherlands)

Huinink, H.

1998-01-01

The aim of this study was to investigate the behavior of surfactants in porous media by theoretical means. The influence of curvature of a surface on the adsorption has been studied with a mean field lattice (MFL) model, as developed by Scheutjens and Fleer. An analytical theory has been

Searches for Long-lived Particles at the Tevatron Collider

International Nuclear Information System (INIS)

Adams, T.; Florida State U.

2008-01-01

Several searches for long-lived particles have been performed using data from p(bar p) collisions from Run II at the Tevatron. In most cases, new analysis techniques have been developed to carry out each search and/or estimate the backgrounds. These searches expand the discovery potential of the CDF and D0 experiments to new physics that may have been missed by traditional search techniques. This review discusses searches for (1) neutral, long-lived particles decaying to muons, (2) massive, neutral, long-lived particles decaying to a photon and missing energy, (3) stopped gluinos, and (4) charged massive stable particles. It summarizes some of the theoretical and experimental motivations for such searches

Theoretical Studies of Small-System Thermodynamics in Energetic Materials

Science.gov (United States)

2016-01-06

SECURITY CLASSIFICATION OF: This is a comprehensive theoretical research program to investigate the fundamental principles of small-system thermodynamics ...a.k.a. nanothermodynamics). The proposed work is motivated by our desire to better understand the fundamental dynamics and thermodynamics of...for Public Release; Distribution Unlimited Final Report: Theoretical Studies of Small-System Thermodynamics in Energetic Materials The views, opinions

The search for a heavy Higgs boson

International Nuclear Information System (INIS)

Dawson, S.

1989-02-01

Theoretical limits on the mass of the Higgs boson from vacuum stability and perturbative unitarity are examined. Search techniques for heavy Higgs bosons, M/sub H/ > 200 GeV, are also reviewed. 8 refs., 5 figs

Surface-Assisted Dynamic Search Processes.

Science.gov (United States)

Shin, Jaeoh; Kolomeisky, Anatoly B

2018-03-01

Many chemical and biological systems exhibit intermittent search phenomena when participating particles alternate between dynamic regimes with different dimensionalities. Here we investigate theoretically a dynamic search process of finding a small target on a two-dimensional surface starting from a bulk solution, which is an example of such an intermittent search process. Both continuum and discrete-state stochastic descriptions are developed. It is found that depending on the scanning length λ, which describes the area visited by the reacting molecule during one search cycle, the system can exhibit three different search regimes: (i) For small λ values, the reactant finds the target mostly via three-dimensional bulk diffusion; (ii) for large λ values, the reactant molecule associates to the target mostly via surface diffusion; and (iii) for intermediate λ values, the reactant reaches the target via a combination of three-dimensional and two-dimensional search cycles. Our analysis also shows that the mean search times have different scalings as a function of the size of the surface segment depending on the nature of the dynamic search regime. Search dynamics are also sensitive to the position of the target for large scanning lengths. In addition, it is argued that the continuum description underestimates mean search times and does not always correctly describe the most optimal conditions for the surface-assisted dynamic processes. The importance of our findings for real natural systems is discussed.

High-throughput theoretical design of lithium battery materials

International Nuclear Information System (INIS)

Ling Shi-Gang; Gao Jian; Xiao Rui-Juan; Chen Li-Quan

2016-01-01

The rapid evolution of high-throughput theoretical design schemes to discover new lithium battery materials is reviewed, including high-capacity cathodes, low-strain cathodes, anodes, solid state electrolytes, and electrolyte additives. With the development of efficient theoretical methods and inexpensive computers, high-throughput theoretical calculations have played an increasingly important role in the discovery of new materials. With the help of automatic simulation flow, many types of materials can be screened, optimized and designed from a structural database according to specific search criteria. In advanced cell technology, new materials for next generation lithium batteries are of great significance to achieve performance, and some representative criteria are: higher energy density, better safety, and faster charge/discharge speed. (topical review)

EXPERIMENT AL AND THEORETICAL STUDY OF PRECAST ...

African Journals Online (AJOL)

EXPERIMENT AL AND THEORETICAL STUDY OF PRECAST BEAM-SLAB. CONSTRUCTION. Girma Zerayohannes and Adil Zekaria. Department of Civil Engineering. Addis Ababa University. ABSTRACT. The use of partially precast beam elements ivith shear connectors in slab construction relieves the requirement of ...

Validation of search filters for identifying pediatric studies in PubMed

NARCIS (Netherlands)

Leclercq, Edith; Leeflang, Mariska M. G.; van Dalen, Elvira C.; Kremer, Leontien C. M.

2013-01-01

To identify and validate PubMed search filters for retrieving studies including children and to develop a new pediatric search filter for PubMed. We developed 2 different datasets of studies to evaluate the performance of the identified pediatric search filters, expressed in terms of sensitivity,

Organizational search and market orientation

DEFF Research Database (Denmark)

Sørensen, Hans Eibe; Stieglitz, Nils

2008-01-01

  Market orientation has evolved into a key construct in the marketing and strategy literature. While much progress has been made in empirical research, the concept lacks a coherent theoretical foundation. Essentially, much prior research has pointed to the role of market-sensing capabilities...... to explain performance differentials among firms (Day, 1994). We open up the black box of market-sensing capabilities by treating the issue of choosing marketing attributes of products as a problem of organizational search. Despite much robust research on organizational search in the strategy......, with their effectiveness depending on organizational and environmental factors. We provide an elaborate outline of the multidimensional aspect of firms' responsive and proactive search processes. First, we highlight the role of organizational aspiration-levels for market orientation. We then investigate the mechanisms...

Citation searching: a systematic review case study of multiple risk behaviour interventions.

Science.gov (United States)

Wright, Kath; Golder, Su; Rodriguez-Lopez, Rocio

2014-06-03

The value of citation searches as part of the systematic review process is currently unknown. While the major guides to conducting systematic reviews state that citation searching should be carried out in addition to searching bibliographic databases there are still few studies in the literature that support this view. Rather than using a predefined search strategy to retrieve studies, citation searching uses known relevant papers to identify further papers. We describe a case study about the effectiveness of using the citation sources Google Scholar, Scopus, Web of Science and OVIDSP MEDLINE to identify records for inclusion in a systematic review.We used the 40 included studies identified by traditional database searches from one systematic review of interventions for multiple risk behaviours. We searched for each of the included studies in the four citation sources to retrieve the details of all papers that have cited these studies.We carried out two analyses; the first was to examine the overlap between the four citation sources to identify which citation tool was the most useful; the second was to investigate whether the citation searches identified any relevant records in addition to those retrieved by the original database searches. The highest number of citations was retrieved from Google Scholar (1680), followed by Scopus (1173), then Web of Science (1095) and lastly OVIDSP (213). To retrieve all the records identified by the citation tracking searching all four resources was required. Google Scholar identified the highest number of unique citations.The citation tracking identified 9 studies that met the review's inclusion criteria. Eight of these had already been identified by the traditional databases searches and identified in the screening process while the ninth was not available in any of the databases when the original searches were carried out. It would, however, have been identified by two of the database search strategies if searches had been

Information-Theoretic Bounded Rationality and ε-Optimality

Directory of Open Access Journals (Sweden)

Daniel A. Braun

2014-08-01

Full Text Available Bounded rationality concerns the study of decision makers with limited information processing resources. Previously, the free energy difference functional has been suggested to model bounded rational decision making, as it provides a natural trade-off between an energy or utility function that is to be optimized and information processing costs that are measured by entropic search costs. The main question of this article is how the information-theoretic free energy model relates to simple ε-optimality models of bounded rational decision making, where the decision maker is satisfied with any action in an ε-neighborhood of the optimal utility. We find that the stochastic policies that optimize the free energy trade-off comply with the notion of ε-optimality. Moreover, this optimality criterion even holds when the environment is adversarial. We conclude that the study of bounded rationality based on ε-optimality criteria that abstract away from the particulars of the information processing constraints is compatible with the information-theoretic free energy model of bounded rationality.

The Search Performance Evaluation and Prediction in Exploratory Search

OpenAIRE

LIU, FEI

2016-01-01

The exploratory search for complex search tasks requires an effective search behavior model to evaluate and predict user search performance. Few studies have investigated the relationship between user search behavior and search performance in exploratory search. This research adopts a mixed approach combining search system development, user search experiment, search query log analysis, and multivariate regression analysis to resolve the knowledge gap. Through this study, it is shown that expl...

Theoretical studies of combustion dynamics

Energy Technology Data Exchange (ETDEWEB)

Bowman, J.M. [Emory Univ., Atlanta, GA (United States)

1993-12-01

The basic objectives of this research program are to develop and apply theoretical techniques to fundamental dynamical processes of importance in gas-phase combustion. There are two major areas currently supported by this grant. One is reactive scattering of diatom-diatom systems, and the other is the dynamics of complex formation and decay based on L{sup 2} methods. In all of these studies, the authors focus on systems that are of interest experimentally, and for which potential energy surfaces based, at least in part, on ab initio calculations are available.

The search image as link between sensation, perception and action.

Science.gov (United States)

Tønnessen, Morten

2018-02-01

In this paper, it is argued that Jakob von Uexküll's "search image" notion, the original version of this notion within ethology, is still of use. A search image, in Uexküll's sense, is an imagined object that an organism has in mind when it searches for something. Uexküll's conception of the search image is useful both for understanding the theoretical context of contemporary notions of search images, and with an eye to envisioning possible future developments of the idea. Uexküll's classical notion differs from contemporary versions in that it has a wider application, and is therefore of greater relevance to theoretical biology and cognitive science. It constituted an integral part of his ground-breaking Umwelt theory, stressing the fundamental plasticity of the Umwelt, the subjective lifeworld of an animal or human subject. In a contemporary development of Umwelt theory, expressed by the tripartite Umwelt model, the search image notion represents a key connection between the directly experienced core Umwelt and the mediated Umwelt. However, the key function that schemata have in cognitive processes is also the starting point for mistakes in perception. This article details both the constructive function search images have in animal and human perception, and the mismatches in perception they can lead to. It also explains how the existence of search images can help explain puzzles concerning subjective and neural time in contemporary cognitive science. Copyright © 2017 Elsevier B.V. All rights reserved.

Searching for a Path: A Bibliometric study on Innovation and Technological Capabilities

Directory of Open Access Journals (Sweden)

João Heitor De Avila Santos

2015-11-01

Full Text Available Innovation is recognize as a matter of survival and success to firms and technological capabilities can lead to an innovative behavior by using technological resources and competences. The literature about technological capability and innovation is vast, counting on several approaches and a large number of researchers involved within. Based on this, our aim is to use a bibliometrics approach to map out the authors, institutions, journals and the evolution of the publication as well, to provide the path needed to build a theoretical framework about the theme. We held this research on the Scopus database using a standard search protocol to perform the selection of the sample. Our results indicates an emerging field of study and a large number papers and citations concentrated in few journals. Most cited authors are related to seminal works on the subject and most cited papers are ones from late 90’s and early 2000. 

A Heuristic Hierarchical Scheme for Academic Search and Retrieval

DEFF Research Database (Denmark)

Amolochitis, Emmanouil; Christou, Ioannis T.; Tan, Zheng-Hua

2013-01-01

and a graph-theoretic computed score that relates the paper’s index terms with each other. We designed and developed a meta-search engine that submits user queries to standard digital repositories of academic publications and re-ranks the repository results using the hierarchical heuristic scheme. We evaluate......, and by more than 907.5% in terms of LEX. We also re-rank the top-10 results of a subset of the original 58 user queries produced by Google Scholar, Microsoft Academic Search, and ArnetMiner; the results show that PubSearch compares very well against these search engines as well. The proposed scheme can...... be easily plugged in any existing search engine for retrieval of academic publications....

Search, Dealers, and the Terms of Trade

OpenAIRE

Gabriele Camera

2001-01-01

I study a search theoretic model with pairwise meetings where dealers arise endogenously. The extent of intermediation depends on its cost, trade frictions, and the dealers' ability to negociate favorable terms of trade. Under Nash bargaining, there is a unique equilibrium where dealers buy and hold the low-storage-cost good and, depending on their relative bargaining power, resell it at a premium or a discount. The distribution of the terms of trade is non-degenerate unless storage cost and ...

The Search for Cosmological Antimatter

Science.gov (United States)

Streitmatter, Robert E.

2004-01-01

For more than 40 years, experimentalists have searched in the cosmic radiation for evidence of antimatter which may have been created in the early Universe. The experimental evidence for cosmologically significant amounts of antimatter in the Universe is reviewed. There is no compelling evidence, either theoretical of experimental. However, the possibility is not completely ruled out.

Searching for Signatures of Supermassive Black Hole Binaries

Science.gov (United States)

Ayers, Megan; Gezari, Suvi; Liu, Tingting

2018-01-01

Theoretical studies suggest that supermassive black hole binaries (SMBHBs) are an inevitable consequence of major galaxy mergers. Additionally, as SMBHBs coalesce they are expected to be sources of tremendous gravitational wave emission. Interest in these sources motivates the search for detection of the first definitive SMBHB and observational signatures to methodize the search. We present spectral energy distributions (SEDs) for a sample of candidate SMBHBs selected from quasars demonstrating optical periodic variability from the Pan-STARRS1 Medium Deep Survey. The SEDs were constructed using existing archival data spanning from radio to X-ray emission. For each candidate SMBHB, we also present models of the theoretical spectrum emitted from the circumbinary and minidisks of the SMBHB system using the predictions of Roedig et al. (2014) and inferred parameters of the candidates (combined mass, mass ratio, binary separation, accretion rate). We compare the observational SED for each source to its respective binary model as well as to the expected mean SED of a normal non-binary system quasar to look for supporting evidence of a SMBHB system. This project was supported in part by the NSF REU grant AST-1358980 and by the Nantucket Maria Mitchell Association.

A Study of Science Education Positions, Search Process, and Hiring Practices

Science.gov (United States)

Barrow, Lloyd H.; Germann, Paul J.

2006-01-01

The purpose of this study was to analyze science education searches and hiring practices for faculty positions listed in The Chronicle of Higher Education for an academic year. Chairs of searches completed a survey about successful and unsuccessful searches. Over 70% of searches were successful in hiring new science education faculty with 33%…

submitter Prospects of Sterile Neutrino Search with the FCC-ee

CERN Document Server

Bay Nielsen, Sissel

A proposed future circular e + e − collider, the FCC-ee, is suggested to search for sterile neutrinos. The Neutrino Minimal Standard Model, νMSM, is a model of sterile neutrinos, that accommodates explanations for several phenomena of physics beyond the Standard Model. This thesis presents an overview of the theoretical motivation for νMSM, an outline of the experimental conditions at the FCC-ee, and a review of previous accelerator bounds for sterile neutrinos. Two studies of sterile neutrinos with masses at the electroweak scale are introduced, an analysis of long lived sterile neutrinos, and an analysis of short lived sterile neutrinos. Both analyses include background studies and sensitivity estimates for the FCC-ee detector. The study of long lived sterile neutrinos is based on a search for detectable displaced vertices with 1012 Z decays, obtaining a search reach on the mixing angle |θ| 2 as small as 10−11. The study of short lived sterile neutrinos is a Monte Carlo study with a cut-based analysi...

WIMP dark matter and supersymmetry searches with neutrino telescopes

International Nuclear Information System (INIS)

Fornengo, N.

2011-01-01

The particle physics interpretation of the missing-mass, or dark-matter, a problem of cosmological and astrophysical nature, is going to be placed under strong scrutiny in the next years. From the particle physics side, accelerator physics will deeply test theoretical ideas about new physics beyond the Standard Model, where a particle physics candidate to dark matter is often naturally obtained. From the astrophysical side, many probes are already providing a great deal of independent information on signals which can be produced by the galactic or extra-galactic dark matter. The current and new-generation experimental efforts are therefore going to place under deep scrutiny the theoretical explanations of the relevant signals. The ultimate hope is in fact to be able to disentangle a dark matter signal from the various sources of backgrounds. Neutrino telescopes are one of the prominent tools for looking at dark matter and search for a signal, the neutrino flux from Earth and Sun. In this neutrino dark matter searches share properties with both direct dark matter searches and cosmic-ray indirect dark matter searches, and therefore complement these different detection techniques.

Sibutramine characterization and solubility, a theoretical study

Science.gov (United States)

Aceves-Hernández, Juan M.; Nicolás Vázquez, Inés; Hinojosa-Torres, Jaime; Penieres Carrillo, Guillermo; Arroyo Razo, Gabriel; Miranda Ruvalcaba, René

2013-04-01

Solubility data from sibutramine (SBA) in a family of alcohols were obtained at different temperatures. Sibutramine was characterized by using thermal analysis and X-ray diffraction technique. Solubility data were obtained by the saturation method. The van't Hoff equation was used to obtain the theoretical solubility values and the ideal solvent activity coefficient. No polymorphic phenomena were found from the X-ray diffraction analysis, even though this compound is a racemic mixture of (+) and (-) enantiomers. Theoretical calculations showed that the polarisable continuum model was able to reproduce the solubility and stability of sibutramine molecule in gas phase, water and a family of alcohols at B3LYP/6-311++G (d,p) level of theory. Dielectric constant, dipolar moment and solubility in water values as physical parameters were used in those theoretical calculations for explaining that behavior. Experimental and theoretical results were compared and good agreement was obtained. Sibutramine solubility increased from methanol to 1-octanol in theoretical and experimental results.

Higgs searches with CMS

CERN Multimedia

CERN. Geneva

2011-01-01

The excellent performances of the LHC in the 2011 run are setting the grounds for the final chase of the Higgs boson. The CMS experiment is recording high quality data that are being thoroughly scrutinized. Several decay channels are investigated to probe the entire possible Higgs mass spectrum, from 110 to 600 GeV/c^2. The study of the first 1.5/fb of collected data places already tight limits and excludes large fractions of the Higgs mass range, leaving however still open the search in the theoretically favored low mass region. In this seminar we will report on the diverse CMS analyses that yield to such results describing the experimental challenges that each had to meet.

Impact of Decorrelation on Search Efficiency of Ambiguity Resolution

Directory of Open Access Journals (Sweden)

LU Liguo

2015-05-01

Full Text Available The decorrelation performance of LAMBDA algorithm, LLL algorithm and Seysen algorithm are analyzed with evaluation indexes, i.e., condition number, orthogonal defect and S(A. Moreover, relationships between decorrelation performance of the above algorithms and ambiguity search efficiency are evaluated using theoretical and practical validation, respectively. The results validate that there is no inevitable relation between decorrelation performance of variance-covariance matrix of original ambiguity and search efficiency, whereas, traditional views consider that search efficiency can be enhanced just by improving decorrelation performance. Further analysis shows that the essence to improving search efficiency major depends on the permutation of basis vectors according to a certain direction.

Theoretical study for solar air pretreatment collector/regenerator

Energy Technology Data Exchange (ETDEWEB)

Peng Donggen; Zhang Xiaosong; Yin Yonggao [School of Energy and Environment, Southeast Univ., Nanjing (China)

2008-07-01

A new liquid regeneration equipment - solar air pretreatment collector/regenerator for liquid desiccant cooling system is put forward in this paper, which is preferable to solution regeneration in hot and moist climate in South China. The equipment can achieve liquid regeneration in lower temperature. When the solution and the air are in ''match'' state in collector/ regenerator, a match air to salt mass ratio ASMR* is found by theoretical study in which there is the largest theoretical storage capacity SC{sub max}. After two new concepts of the effective solution proportion (EPS) and the effective storage capacity (ESC) are defined, it is found by theoretical calculation that when ESP drops from 100% to 67%, ESC raises lowly, not drops and liquid outlet concentration C{sub str} {sub sol} increases from 40% to 49% in which its increment totals to 90%. All these data explain fully that air pretreatment liquid regeneration equipment enables to improve the performance of liquid desiccant cooling system. (orig.)

Search for lepton-family-number nonconservation

International Nuclear Information System (INIS)

Hoffman, C.M.

1986-01-01

A review of the status of lepton-family-number nonconservation is given. After a brief historical and theoretical discussion, a description of how experimental searches for lepton-family-number nonconservation are performed is presented. Finally, a summary of the results from past experiments and prospects for future experiments is given

A critical analysis of the harmony search algorithm—How not to solve sudoku

Directory of Open Access Journals (Sweden)

Dennis Weyland

2015-12-01

Based on these findings, we carefully examine the results found in the paper Harmony search algorithm for solving sudoku. A theoretical investigation and a reimplementation of the harmony search algorithm both reveal that these results are fundamentally flawed.

Strategic search from long-term memory: an examination of semantic and autobiographical recall.

Science.gov (United States)

Unsworth, Nash; Brewer, Gene A; Spillers, Gregory J

2014-01-01

Searching long-term memory is theoretically driven by both directed (search strategies) and random components. In the current study we conducted four experiments evaluating strategic search in semantic and autobiographical memory. Participants were required to generate either exemplars from the category of animals or the names of their friends for several minutes. Self-reported strategies suggested that participants typically relied on visualization strategies for both tasks and were less likely to rely on ordered strategies (e.g., alphabetic search). When participants were instructed to use particular strategies, the visualization strategy resulted in the highest levels of performance and the most efficient search, whereas ordered strategies resulted in the lowest levels of performance and fairly inefficient search. These results are consistent with the notion that retrieval from long-term memory is driven, in part, by search strategies employed by the individual, and that one particularly efficient strategy is to visualize various situational contexts that one has experienced in the past in order to constrain the search and generate the desired information.

Searches for non-Standard Model Higgs bosons

CERN Document Server

Dumitriu, Ana Elena; The ATLAS collaboration

2018-01-01

This presentation focuses on the Searches for non-Standard Model Higgs bosons using 36.1 fb of data collected by the ATLAS experiment. There are several theoretical models with an extended Higgs sector considered: 2 Higgs Doublet Models (2HDM), Supersymmetry (SUSY), which brings along super-partners of the SM particles (+ The Minimal Supersymmetric Standard Model (MSSM), whose Higgs sector is equivalent to the one of a constrained 2HDM of type II and the next-to MSSM (NMSSM)), General searches and Invisible decaying Higgs boson.

Theoretical and simulation studies of seeding methods

Energy Technology Data Exchange (ETDEWEB)

Pellegrini, Claudio [Univ. of California, Los Angeles, CA (United States)

2017-12-11

We report the theoretical and experimental studies done with the support of DOE-Grant DE-SC0009983 to increase an X-ray FEL peak power from the present level of 20 to 40 GW to one or more TW by seeding, undulator tapering and using the new concept of the Double Bunch FEL.

Theoretical spectroscopic study of the conjugate microcystin-LR-europium cryptate

Energy Technology Data Exchange (ETDEWEB)

Santos, Julio G.; Dutra, Jose Diogo L.; Costa Junior, Nivan B. da; Freire, Ricardo O., E-mail: rfreire@ufs.br [Universidade Federal de Sergipe (UFS), Sao Cristovao, SE (Brazil). Departamento de Quimica; Alves Junior, Severino; Sa, Gilberto F. de [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Departamento de Quimica Fundamental

2013-02-15

In this work, theoretical tools were used to study spectroscopic properties of the conjugate microcystin-LR-europium cryptate. The Sparkle/AM1 model was applied to predict the geometry of the system and the INDO/S-CIS model was used to calculate the excited state energies. Based on the Judd-Ofelt theory, the intensity parameters were predicted and a theoretical model based on the theory of the 4f-4f transitions was applied to calculate energy transfer and backtransfer rates, radiative and non-radiative decay rates, quantum efficiency and quantum yield. A detailed study of the luminescent properties of the conjugate Microcystin-LR-europium cryptate was carried out. The results show that the theoretical quantum yield of luminescence of 23% is in good agreement with the experimental value published. This fact suggests that this theoretical protocol can be used to design new systems in order to improve their luminescence properties. The results suggest that this luminescent system may be a good conjugate for using in assay ELISA for detection by luminescence of the Microcystin-LR in water. (author)

Searching for supersymmetry at the LHC

CERN Multimedia

CERN. Geneva. Audiovisual Unit; Ridolfi, Giovanni

2003-01-01

We will review the general motivations for proposing non-standard descriptions of fundamental interactions. We will give a simple and pedagogical presentation of the theoretical foundations of Supersymmetry, and we will describe the main features of a realistic supersymmetric extension of the Standard Model. We will present the phenomenology expected in several motivated scenarios. We will then review the present status of the experimental searches for Supersymmetry at LEP and Tevatron, and discuss prospects at future machines with emphasis on the LHC. We will outline the search strategies and the analysis methods, and compare the sensitivity and reach of the various machines.

The spatially global control of attentional target selection in visual search

OpenAIRE

Berggren, Nick; Jenkins, M.; McCants, C.W.; Eimer, Martin

2017-01-01

Glyn Humphreys and his co-workers have made numerous important theoretical and empirical contributions to research on visual search. They have introduced the concept of attentional target templates and investigated the nature of these templates and how they are involved in the control of search performance. In the experiments reported here, we investigated whether feature-specific search template for particular colours can guide target selection independently for different regions of visual s...

For a new dialogue between theoretical and empirical studies in evo-devo

Directory of Open Access Journals (Sweden)

Giuseppe eFusco

2015-08-01

Full Text Available Despite its potentially broad scope, current evo-devo research is largely dominated by empirical developmental studies, whereas comparably little role is played by theoretical research. I argue that this represents an obstacle to a wider appreciation of evo-devo and its integration within a more comprehensive evolutionary theory, and that this situation is causally linked to a limited exchange between theoretical and experimental studies in evo-devo. I discuss some features of current theoretical work in evo-devo, highlighting some possibly concurring impediments to an effective dialogue with experimental studies. Finally, I advance two suggestions for enhancing fruitful cross-fertilization between theoretical and empirical studies in evo-devo: i to broaden the scope of evo-devo beyond its current conceptualization, teaming up with other variational approaches to the study of evolution, and ii to develop more effective forms of scientific interaction and communication.

Category Theory Approach to Solution Searching Based on Photoexcitation Transfer Dynamics

Directory of Open Access Journals (Sweden)

Makoto Naruse

2017-07-01

Full Text Available Solution searching that accompanies combinatorial explosion is one of the most important issues in the age of artificial intelligence. Natural intelligence, which exploits natural processes for intelligent functions, is expected to help resolve or alleviate the difficulties of conventional computing paradigms and technologies. In fact, we have shown that a single-celled organism such as an amoeba can solve constraint satisfaction problems and related optimization problems as well as demonstrate experimental systems based on non-organic systems such as optical energy transfer involving near-field interactions. However, the fundamental mechanisms and limitations behind solution searching based on natural processes have not yet been understood. Herein, we present a theoretical background of solution searching based on optical excitation transfer from a category-theoretic standpoint. One important indication inspired by the category theory is that the satisfaction of short exact sequences is critical for an adequate computational operation that determines the flow of time for the system and is termed as “short-exact-sequence-based time.” In addition, the octahedral and braid structures known in triangulated categories provide a clear understanding of the underlying mechanisms, including a quantitative indication of the difficulties of obtaining solutions based on homology dimension. This study contributes to providing a fundamental background of natural intelligence.

THEORETICAL ASPECTS OF FILMMUSIC STUDY

Directory of Open Access Journals (Sweden)

Egorova Tatiana K.

2014-04-01

Full Text Available In this article, author analyzes the theoretical aspects of the film music study taking into account with modern realities in the development of world film-process and attempts to its scientific understanding. Need for innovation in this area is long overdue, because the existing on this topic nonfiction no longer meets the new aesthetic and art-practical achievements and innovations in the film music development at the XXI century. Related to the phenomenon of music in screen arts a number of new terms and concepts require a certain adjustment as well. Their range of action is not yet fully defined. Author of the article offered her version of their content-semantic interpretation (largely experimental designed to promote new research methods for the film music study.

Internet Search Engines

OpenAIRE

Fatmaa El Zahraa Mohamed Abdou

2004-01-01

A general study about the internet search engines, the study deals main 7 points; the differance between search engines and search directories, components of search engines, the percentage of sites covered by search engines, cataloging of sites, the needed time for sites appearance in search engines, search capabilities, and types of search engines.

Search for semileptonic decays of photoproduced charmed mesons

International Nuclear Information System (INIS)

Coleman, R.N.

1977-01-01

In the broad band neutral beam at Fermilab, a search for photoproduction of charmed D mesons was done using photons of 100 to 300 GeV. The reaction considered was γ + Be → DantiD + X, leptons + ..., K 0 /sub s/nπ/sup +-/. No statistically significant evidence for D production is observed based on the K 0 /sub s/nπ/sup +-/ mass spectrum. The sensitivity of the search is commensurate with theoretical estimates of sigma(γp → DantiD + X) approximately 500 nb, however this is dependent on branching ratios and photoproduction models. Data are given on a similar search for semileptonic decays of charmed baryons. 48 references

News search, blogs and feeds a toolkit

CERN Document Server

Vage, Lars

2010-01-01

This book is about news search and monitoring. Aimed at professionals with a strategic need of monitoring the surrounding world, users with a need to find the best news sources, monitoring services and news search strategies and techniques will benefit from reading this book. The main purpose is to present a practical handbook with an analysis of readily available tools, blending with passages of a theoretical nature. It is also useful for students at LIS programmes and related information programmes and for librarians and information professionals. The authors aim to aid the reader in reachin

The search for proton decay

International Nuclear Information System (INIS)

Haines, T.; Kaneyuki, K.; McGrew, C.; Mohapatra, R.; Peterson, E.; Cline, D.B.

1994-01-01

The conservation of the quantum number called baryon number, like lepton (or family) number, is an empirical fact even though there are very good reasons to expect otherwise. Experimentalists have been searching for baryon number violating decays of the proton and neutron for decades now without success. Theorists have evolved deep understanding of the relationship between the natural forces in the development of various Grand Unified Theories (GUTs) that nearly universally predict baryon number violating proton decay, or related phenomena like n-bar n oscillations. With this in mind, the Proton Decay Working Group reviewed the current experimental and theoretical status of the search for baryon number violation with an eye to the advancement in the next decade

Searches for new physics

International Nuclear Information System (INIS)

Ellis, J.; Pauss, F.

1989-01-01

The CERN p bar p Collider has been the first accelerator to operate in a completely new energy domain, reaching center-of-mass energies an order of magnitude larger than those previously available with the intersecting Storage Rings (ISR) at CERN, or with the Positron-Electron Tandem Ring Accelerator (PETRA) at DESY and the Positron-Electron Project (PEP) at SLAC. Naturally there has been great interest in the searches for new physics in this virgin territory. Theorists have approached these searches from either or both of two rival points of view. Either they have had an a priori prejudice as to what new physics should be searched for, and what its signatures should be, or they have tried to interpret a posteriori some experimental observations. The basic building-blocks of new physics in the 100 GeV energy domain are jets j, charged leptons l, photons γ, and missing transverse energy E T . Therefore searches have been conducted in channels which are combinations of these elements. It also shows some of the main a priori theoretical prejudices which can be explored in each of these channels. The layout of the rest of this paper is as follows. There are sections discussing each of the major prejudices: the Standard Model supersymmetry; extra gauge degrees of freedom; composite models; and other possibilities. Each of these sections contains a description of the motivations and characteristics of the new physics to be searched for, followed by a review of the searches made up to now at the CERN p bar p Collider. Finally, it summarizes the lessons to be learnt so far from searches for new physics at the CERN p bar p Collider, and previews some of the prospects for the next rounds of collider searches at CERN and FNAL

Virtual Reference Services through Web Search Engines: Study of Academic Libraries in Pakistan

Directory of Open Access Journals (Sweden)

Rubia Khan

2017-03-01

Full Text Available Web search engines (WSE are powerful and popular tools in the field of information service management. This study is an attempt to examine the impact and usefulness of web search engines in providing virtual reference services (VRS within academic libraries in Pakistan. The study also attempts to investigate the relevant expertise and skills of library professionals in providing digital reference services (DRS efficiently using web search engines. Methodology used in this study is quantitative in nature. The data was collected from fifty public and private sector universities in Pakistan using a structured questionnaire. Microsoft Excel and SPSS were used for data analysis. The study concludes that web search engines are commonly used by librarians to help users (especially research scholars by providing digital reference services. The study also finds a positive correlation between use of web search engines and quality of digital reference services provided to library users. It is concluded that although search engines have increased the expectations of users and are really big competitors to a library’s reference desk, they are however not an alternative to reference service. Findings reveal that search engines pose numerous challenges for librarians and the study also attempts to bring together possible remedial measures. This study is useful for library professionals to understand the importance of search engines in providing VRS. The study also provides an intellectual comparison among different search engines, their capabilities, limitations, challenges and opportunities to provide VRS effectively in libraries.

Theoretical studies on core-level spectra of solids

International Nuclear Information System (INIS)

Kotani, Akio

1995-01-01

I present a review on theoretical studies of core-level spectra (CLS) in solids. In CLS, the dynamical response of outer electrons to a core hole is reflected through the screening of core hole potential. Impurity Anderson model (IAM) or cluster model is successfully applied to the analysis of X-ray photoemission spectra (XPS) and X-ray absorption spectra (XAS) in f and d electron systems, where the f and d electron states are hybridized with the other valence or conduction electron states. The effect of the core-hole potential in the final state of XPS and XAS plays an important role, as well as the solid state hybridization and intra-atomic multiplet coupling effects. As typical examples, the calculated results for XPS of rare-earth compounds and transition metal compounds are shown, and some discussions are given. As a subject of remarkable progress with high brightness synchrotron radiation sources, I discuss some theoretical aspects of X-ray emission spectra (XES) and their resonant enhancement at the X-ray absorption threshold. Some experimental data and their theoretical analysis are also given. (author)

Theoretical and Methodological Perspectives on Designing Video Studies of Interaction

Directory of Open Access Journals (Sweden)

Anna-Lena Rostvall

2005-12-01

Full Text Available In this article the authors discuss the theoretical basis for the methodological decisions made during the course of a Swedish research project on interaction and learning. The purpose is to discuss how different theories are applied at separate levels of the study. The study is structured on three levels, with separate sets of research questions and theoretical concepts. The levels reflect a close-up description, a systematic analysis, and an interpretation of how teachers and students act and interact. The data consist of 12 hours of video-recorded and transcribed music lessons from high school and college. Through a multidisciplinary theoretical framework, the general understanding of teaching and learning in terms of interaction can be widened. The authors also present a software tool developed to facilitate the processes of transcription and analysis of the video data.

Theoretical explanations for maintenance of behaviour change: a systematic review of behaviour theories.

Science.gov (United States)

Kwasnicka, Dominika; Dombrowski, Stephan U; White, Martin; Sniehotta, Falko

2016-09-01

Behaviour change interventions are effective in supporting individuals in achieving temporary behaviour change. Behaviour change maintenance, however, is rarely attained. The aim of this review was to identify and synthesise current theoretical explanations for behaviour change maintenance to inform future research and practice. Potentially relevant theories were identified through systematic searches of electronic databases (Ovid MEDLINE, Embase, PsycINFO). In addition, an existing database of 80 theories was searched, and 25 theory experts were consulted. Theories were included if they formulated hypotheses about behaviour change maintenance. Included theories were synthesised thematically to ascertain overarching explanations for behaviour change maintenance. Initial theoretical themes were cross-validated. One hundred and seventeen behaviour theories were identified, of which 100 met the inclusion criteria. Five overarching, interconnected themes representing theoretical explanations for behaviour change maintenance emerged. Theoretical explanations of behaviour change maintenance focus on the differential nature and role of motives, self-regulation, resources (psychological and physical), habits, and environmental and social influences from initiation to maintenance. There are distinct patterns of theoretical explanations for behaviour change and for behaviour change maintenance. The findings from this review can guide the development and evaluation of interventions promoting maintenance of health behaviours and help in the development of an integrated theory of behaviour change maintenance.

Searching for Heavy Photons with Detached Verices in the Heavy Photon Search Experiment

Energy Technology Data Exchange (ETDEWEB)

Szumila-Vance, Holly [Old Dominion Univ., Norfolk, VA (United States); Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

2017-08-01

The Jefferson Lab Heavy Photon Search (HPS) experiment is searching for a hypothetical massive particle called the heavy photon which could mediate a dark electromagnetic-type force. If heavy photons kinetically mix with Standard Model photons, they may be radiated by electrons scattering from a heavy nucleus and then decay to e+e- pairs. HPS uniquely searches for heavy photons that either decay at the target or a measurable distance after. The experiment utilizes a silicon vertex tracker (SVT) for momentum and vertex reconstruction, together with an electromagnetic calorimeter for measuring particle energies and triggering events. The HPS experiment took its first data during the spring 2015 engineering run using a 1 GeV electron beam incident on a tungsten target and its second data in the spring of 2016 at a beam energy of 2.3 GeV. The 2015 run obtained two days of production data that was used for the first physics results. The analysis of the data was conducted as a blinded analysis by tuning cuts on 10% of the data. This dissertation discusses the displaced vertex search for heavy photons in the 2015 engineering run. It describes the theoretical motivation for looking for heavy photons and provides an overview of the HPS experimental design and performance. The performance details of the experiment are primarily derived from the 2015 engineering run with some discussion from the higher energy running in 2016. This dissertation further discusses the cuts used to optimize the displaced vertex search and the results of the search. The displaced vertex search did not set a limit on the heavy photon but did validate the methodology for conducting the search. Finally, we used the full data set to make projections and guide future analyses.

W′ and Z′ searches at the LHC

DEFF Research Database (Denmark)

Accomando, E.; Becciolini, D.; Belyaev, A.

Searches for extra heavy W′ and Z′-bosons in the leptonic Drell-Yan channel at the Large Hadron Collider (LHC) are favoured by present and future data. We focus on a common approximation used in theoretical and experimental analyses: neglecting interference between the new gauge bosons W′± (Z...

Search for axion production in Υ(1S) decays

International Nuclear Information System (INIS)

Fairfield, K.H.

1988-06-01

We present a search for axion production in radiative Υ(1S) decays using the Crystal Ball detector. We find no evidence for a signal and give a new upper limit, Br[Υ(1S)→a/degree/γ] < 4 /times/ 10/sup /minus/5/, for m/sub a/ < 2m/sub e/. Results from previous axion searches in both the Υ and J//psi/ systems are discussed and compared to theoretical predictions

Modelling foraging movements of diving predators: a theoretical study exploring the effect of heterogeneous landscapes on foraging efficiency

Directory of Open Access Journals (Sweden)

Marianna Chimienti

2014-09-01

Full Text Available Foraging in the marine environment presents particular challenges for air-breathing predators. Information about prey capture rates, the strategies that diving predators use to maximise prey encounter rates and foraging success are still largely unknown and difficult to observe. As well, with the growing awareness of potential climate change impacts and the increasing interest in the development of renewable sources it is unknown how the foraging activity of diving predators such as seabirds will respond to both the presence of underwater structures and the potential corresponding changes in prey distributions. Motivated by this issue we developed a theoretical model to gain general understanding of how the foraging efficiency of diving predators may vary according to landscape structure and foraging strategy. Our theoretical model highlights that animal movements, intervals between prey capture and foraging efficiency are likely to critically depend on the distribution of the prey resource and the size and distribution of introduced underwater structures. For multiple prey loaders, changes in prey distribution affected the searching time necessary to catch a set amount of prey which in turn affected the foraging efficiency. The spatial aggregation of prey around small devices (∼ 9 × 9 m created a valuable habitat for a successful foraging activity resulting in shorter intervals between prey captures and higher foraging efficiency. The presence of large devices (∼ 24 × 24 m however represented an obstacle for predator movement, thus increasing the intervals between prey captures. In contrast, for single prey loaders the introduction of spatial aggregation of the resources did not represent an advantage suggesting that their foraging efficiency is more strongly affected by other factors such as the timing to find the first prey item which was found to occur faster in the presence of large devices. The development of this theoretical model

Search for exotic mesons at SLAC

International Nuclear Information System (INIS)

Bonamy, P.; Baggett, N.; Fieguth, T.

1975-01-01

The theoretical justification and results from recent experimental searches for backward-produced exotic mesons including two experiments carried out by the collaboration at SLAC are reviewed. The first experiment put upper limits of about 1 to 2 μb for X ++ → (2π, 4π, 6π) ++ and anti ppπ + π + in the reaction π + + p → X ++ + n/sub forward/ at 8.4 GeV/c studied with the SLAC 14 inch rapid cycling bubble chamber triggered by a downstream neutron detector. Also the important features of the recently completed second experiment with the SLAC streamer chamber to study the reaction π - + p → X -- + p/sub forward/ at 14 GeV/c are discussed

Toward a comprehensive, theoretical model of compassion fatigue: An integrative literature review.

Science.gov (United States)

Coetzee, Siedine K; Laschinger, Heather K S

2018-03-01

This study was an integrative literature review in relation to compassion fatigue models, appraising these models, and developing a comprehensive theoretical model of compassion fatigue. A systematic search on PubMed, EbscoHost (Academic Search Premier, E-Journals, Medline, PsycINFO, Health Source Nursing/Academic Edition, CINAHL, MasterFILE Premier and Health Source Consumer Edition), gray literature, and manual searches of included reference lists was conducted in 2016. The studies (n = 11) were analyzed, and the strengths and limitations of the compassion fatigue models identified. We further built on these models through the application of the conservation of resources theory and the social neuroscience of empathy. The compassion fatigue model shows that it is not empathy that puts nurses at risk of developing compassion fatigue, but rather a lack of resources, inadequate positive feedback, and the nurse's response to personal distress. By acting on these three aspects, the risk of developing compassion fatigue can be addressed, which could improve the retention of a compassionate and committed nurse workforce. © 2017 John Wiley & Sons Australia, Ltd.

A search strategy for occupational health intervention studies

NARCIS (Netherlands)

Verbeek, J.; Salmi, J.; Pasternack, I.; Jauhiainen, M.; Laamanen, I.; Schaafsma, F.; Hulshof, C.; van Dijk, F.

2005-01-01

As a result of low numbers and diversity in study type, occupational health intervention studies are not easy to locate in electronic literature databases. To develop a search strategy that facilitates finding occupational health intervention studies in Medline, both for researchers and

Numerical Algorithms for Personalized Search in Self-organizing Information Networks

CERN Document Server

Kamvar, Sep

2010-01-01

This book lays out the theoretical groundwork for personalized search and reputation management, both on the Web and in peer-to-peer and social networks. Representing much of the foundational research in this field, the book develops scalable algorithms that exploit the graphlike properties underlying personalized search and reputation management, and delves into realistic scenarios regarding Web-scale data. Sep Kamvar focuses on eigenvector-based techniques in Web search, introducing a personalized variant of Google's PageRank algorithm, and he outlines algorithms--such as the now-famous quad

An in-depth analysis of theoretical frameworks for the study of care coordination

Directory of Open Access Journals (Sweden)

Sabine Van Houdt

2013-06-01

Full Text Available Introduction: Complex chronic conditions often require long-term care from various healthcare professionals. Thus, maintaining quality care requires care coordination. Concepts for the study of care coordination require clarification to develop, study and evaluate coordination strategies. In 2007, the Agency for Healthcare Research and Quality defined care coordination and proposed five theoretical frameworks for exploring care coordination. This study aimed to update current theoretical frameworks and clarify key concepts related to care coordination. Methods: We performed a literature review to update existing theoretical frameworks. An in-depth analysis of these theoretical frameworks was conducted to formulate key concepts related to care coordination.Results: Our literature review found seven previously unidentified theoretical frameworks for studying care coordination. The in-depth analysis identified fourteen key concepts that the theoretical frameworks addressed. These were ‘external factors’, ‘structure’, ‘tasks characteristics’, ‘cultural factors’, ‘knowledge and technology’, ‘need for coordination’, ‘administrative operational processes’, ‘exchange of information’, ‘goals’, ‘roles’, ‘quality of relationship’, ‘patient outcome’, ‘team outcome’, and ‘(interorganizational outcome’.Conclusion: These 14 interrelated key concepts provide a base to develop or choose a framework for studying care coordination. The relational coordination theory and the multi-level framework are interesting as these are the most comprehensive.

Search for Hidden Particles (SHiP): a new experiment proposal

Science.gov (United States)

De Lellis, G.

2015-06-01

Searches for new physics with accelerators are being performed at the LHC, looking for high massive particles coupled to matter with ordinary strength. We propose a new experimental facility meant to search for very weakly coupled particles in the few GeV mass domain. The existence of such particles, foreseen in different theoretical models beyond the Standard Model, is largely unexplored from the experimental point of view. A beam dump facility, built at CERN in the north area, using 400 GeV protons is a copious factory of charmed hadrons and could be used to probe the existence of such particles. The beam dump is also an ideal source of tau neutrinos, the less known particle in the Standard Model. In particular, tau anti-neutrinos have not been observed so far. We therefore propose an experiment to search for hidden particles and study tau neutrino physics at the same time.

Theoretical and experimental studies of elementary particles

International Nuclear Information System (INIS)

Bodek, A.; Ferbel, T.; Melissinos, A.C.; Olsen, S.L.; Slattery, P.; Tipton, P.; Das, A.; Hagen, C.R.; Rajeev, S.G.; Okubo, S.

1991-01-01

This report discusses: Fixed target experimentation at Fermilab; the D-zero collider experiment at Fermilab; deep inelastic lepton nucleon scattering; non-accelerator experiments and non-linear QED; the AMY experiment at TRISTAN and other activities at KEK; the collider detector at Fermilab; laser switched linac; preparations for experiments at the SSC; search for massive stable particles; and the Advanced Study Institute on techniques and concepts of high energy physics

Optimal search strategies for detecting cost and economic studies in EMBASE

Directory of Open Access Journals (Sweden)

Haynes R Brian

2006-06-01

Full Text Available Abstract Background Economic evaluations in the medical literature compare competing diagnosis or treatment methods for their use of resources and their expected outcomes. The best evidence currently available from research regarding both cost and economic comparisons will continue to expand as this type of information becomes more important in today's clinical practice. Researchers and clinicians need quick, reliable ways to access this information. A key source of this type of information is large bibliographic databases such as EMBASE. The objective of this study was to develop search strategies that optimize the retrieval of health costs and economics studies from EMBASE. Methods We conducted an analytic survey, comparing hand searches of journals with retrievals from EMBASE for candidate search terms and combinations. 6 research assistants read all issues of 55 journals indexed by EMBASE for the publishing year 2000. We rated all articles using purpose and quality indicators and categorized them into clinically relevant original studies, review articles, general papers, or case reports. The original and review articles were then categorized for purpose (i.e., cost and economics and other clinical topics and depending on the purpose as 'pass' or 'fail' for methodologic rigor. Candidate search strategies were developed for economic and cost studies, then run in the 55 EMBASE journals, the retrievals being compared with the hand search data. The sensitivity, specificity, precision, and accuracy of the search strategies were calculated. Results Combinations of search terms for detecting both cost and economic studies attained levels of 100% sensitivity with specificity levels of 92.9% and 92.3% respectively. When maximizing for both sensitivity and specificity, the combination of terms for detecting cost studies (sensitivity increased 2.2% over the single term but at a slight decrease in specificity of 0.9%. The maximized combination of terms

Search strategies to identify diagnostic accuracy studies in MEDLINE and EMBASE

NARCIS (Netherlands)

Beynon, Rebecca; Leeflang, Mariska M. G.; McDonald, Steve; Eisinga, Anne; Mitchell, Ruth L.; Whiting, Penny; Glanville, Julie M.

2013-01-01

A systematic and extensive search for as many eligible studies as possible is essential in any systematic review. When searching for diagnostic test accuracy (DTA) studies in bibliographic databases, it is recommended that terms for disease (target condition) are combined with terms for the

Theoretical study of nuclear physics with strangeness at Nankai University

International Nuclear Information System (INIS)

Ning Pingzhi

2007-01-01

Theoretical study of nuclear physics with strangeness from the nuclear physics group at Nankai university is briefly introduced. Theoretical calculations on hyperon mean free paths in nuclear medium have been done. The other 4 topics in the area of strangeness nuclear physics are the effect of different baryon impurities in nucleus, the heavy flavored baryon hypernuclei, the eta-mesons in nuclear matter and the properties of kaonic nuclei. (authors)

An event-related potential study on memory search for color

OpenAIRE

Miyatani, Makoto; Nakao, Takasi; Ohkawa, Kaori; Sanderson, Nicholas S. R.; Takumi, Ken

2002-01-01

The present study focused on memory search processes in nonverbal working memory. Event-related potentials (ERPs) were recorded while subjects engaged in two memory search tasks. Effects of memory set size on event-related potentials were compared between when memory sets consisted of one or four alphabets and when one to three unvocable color patches composed memory sets. In a letter search task, increase of memory set size caused the enlargement of negativities of ERPs between 250 and 450 m...

Using Google Search Appliance (GSA) to search digital library collections: A Case Study of the INIS Collection Search

International Nuclear Information System (INIS)

Savic, Dobrica

2014-01-01

Google Search has established a new standard for information retrieval which did not exist with previous generations of library search facilities. The INIS hosts one of the world’s largest collections of published information on the peaceful uses of nuclear science and technology. It offers on-line access to a unique collection of 3.6 million bibliographic records and 483,000 full texts of non-conventional (grey) literature. This large digital library collection suffered from most of the well-known shortcomings of the classic library catalogue. Searching was complex and complicated, it required training in Boolean logic, full-text searching was not an option, and response time was slow. An opportune moment to improve the system came with the retirement of the previous catalogue software and the adoption of GSA as an organization-wide search engine standard. INIS was quick to realize the potential of using such a well-known application to replace its on-line catalogue. This paper presents the advantages and disadvantages encountered during three years of GSA use. Based on specific INIS-based practice and experience, this paper also offers some guidelines on ways to improve classic collections of millions of bibliographic and full-text documents, while reaping multiple benefits, such as increased use, accessibility, usability, expandability and improving user search and retrieval experiences. (author)

Searches for lepton flavor violation

International Nuclear Information System (INIS)

Bryman, D.

1986-01-01

The search for lepton flavor violation has reached considerable sensitivity, but with only null results so far. The experiments are sensitive to new particle in the 1 to 100 TeV range arising in a variety of theories, although the constraints on the masses of such particles improve only as the inverse fourth power of branching ratios. Presenting, neutrinoless μe conversion in the field of a nucleus provides the most serious constraints for many models. New experiments on rare kaon decays γe conversion and μ → eγ will result in improved sensitivity in the next few years. Ignoring theoretical prejudice, it is important to study many different processes in the hope uncovering some new effects

Sequence heterogeneity accelerates protein search for targets on DNA

International Nuclear Information System (INIS)

Shvets, Alexey A.; Kolomeisky, Anatoly B.

2015-01-01

The process of protein search for specific binding sites on DNA is fundamentally important since it marks the beginning of all major biological processes. We present a theoretical investigation that probes the role of DNA sequence symmetry, heterogeneity, and chemical composition in the protein search dynamics. Using a discrete-state stochastic approach with a first-passage events analysis, which takes into account the most relevant physical-chemical processes, a full analytical description of the search dynamics is obtained. It is found that, contrary to existing views, the protein search is generally faster on DNA with more heterogeneous sequences. In addition, the search dynamics might be affected by the chemical composition near the target site. The physical origins of these phenomena are discussed. Our results suggest that biological processes might be effectively regulated by modifying chemical composition, symmetry, and heterogeneity of a genome

Sequence heterogeneity accelerates protein search for targets on DNA

Energy Technology Data Exchange (ETDEWEB)

Shvets, Alexey A.; Kolomeisky, Anatoly B., E-mail: tolya@rice.edu [Department of Chemistry and Center for Theoretical Biological Physics, Rice University, Houston, Texas 77005 (United States)

2015-12-28

The process of protein search for specific binding sites on DNA is fundamentally important since it marks the beginning of all major biological processes. We present a theoretical investigation that probes the role of DNA sequence symmetry, heterogeneity, and chemical composition in the protein search dynamics. Using a discrete-state stochastic approach with a first-passage events analysis, which takes into account the most relevant physical-chemical processes, a full analytical description of the search dynamics is obtained. It is found that, contrary to existing views, the protein search is generally faster on DNA with more heterogeneous sequences. In addition, the search dynamics might be affected by the chemical composition near the target site. The physical origins of these phenomena are discussed. Our results suggest that biological processes might be effectively regulated by modifying chemical composition, symmetry, and heterogeneity of a genome.

Theoretical and experimental study of fenofibrate and simvastatin

Science.gov (United States)

Nicolás Vázquez, Inés; Rodríguez-Núñez, Jesús Rubén; Peña-Caballero, Vicente; Ruvalcaba, Rene Miranda; Aceves-Hernandez, Juan Manuel

2017-12-01

Fenofibrate, an oral fibrate lipid lowering agent, and simvastatin, which reduces plasma levels of low-density lipoprotein cholesterol, are active pharmaceutical ingredients (APIs), currently in the market. We characterized these APIs by thermal analysis and conducted X-ray powder diffraction techniques. Studies should be carried out in the formulation stage before the final composition of a polypill may be established. Thus, it was found in thermochemical studies that both compounds present no chemical interactions in an equimolar mixture of solid samples at room temperature. Theoretical studies were employed to determine possible interactions between fenofibrate and simvastatin. A very weak intramolecular hydrogen bond is formed between the hydroxyl group (O5H5) of the simvastatin with chlorine and carbonyl group (C11O4, C1O2) of the fenofibrate molecule. These weak energy hydrogen bonds have no effect on the chemical stability of the compounds studied. The results were obtained using Density Functional Theory methods; particularly the BPE1BPE and B3LYP functional and 6-31++G** basis set. The values of energy show good approximation when are compared with similar calculations previously reported. Infrared spectra of monomers and dimers were obtained via theoretical calculations.

Strategies to improve sleep during extended search and rescue operations.

Science.gov (United States)

Jenkins, Jennifer Lee; Fredericksen, Kim; Stone, Roger; Tang, Nelson

2007-01-01

This study investigated strategies to improve sleeping conditions during search and rescue operations during disaster response. Forty members of the Montgomery County (Maryland) Urban Search and Rescue Team were surveyed for individual sleep habits and sleeping aids used during extended deployments. Team members were also asked to suggest methods to improve sleep on future deployments. The average amount of sleep during field operations was 5.4 hours with a range of 4-8 hours. Eight percent surveyed would prefer another schedule besides the 12-hour work day, all of whom proposed three 8-hour shifts. Fifteen percent of participants were interested in a pharmacological sleeping aid. Fifty percent of search and rescue members interviewed would consider using nonpharmacological sleeping aids. Furthermore, 40% of participants stated they had successfully devised self-employed methods of sleep aids for previous deployments, such as ear plugs, massage, mental imagery, personal routines, music and headphones, reading, and blindfolds. This study suggests that availability of both pharmacological and nonpharmacological sleeping aids to search and rescue workers via the team cache could impact the quantity of sleep. Further investigation into methods of optimizing sleep during field missions could theoretically show enhanced performance through various aspects of missions including mitigation of errors, improved productivity, and improved overall physiological and emotional well-being of search and rescue personnel.

Assessment of Metabolome Annotation Quality: A Method for Evaluating the False Discovery Rate of Elemental Composition Searches

Science.gov (United States)

Matsuda, Fumio; Shinbo, Yoko; Oikawa, Akira; Hirai, Masami Yokota; Fiehn, Oliver; Kanaya, Shigehiko; Saito, Kazuki

2009-01-01

Background In metabolomics researches using mass spectrometry (MS), systematic searching of high-resolution mass data against compound databases is often the first step of metabolite annotation to determine elemental compositions possessing similar theoretical mass numbers. However, incorrect hits derived from errors in mass analyses will be included in the results of elemental composition searches. To assess the quality of peak annotation information, a novel methodology for false discovery rates (FDR) evaluation is presented in this study. Based on the FDR analyses, several aspects of an elemental composition search, including setting a threshold, estimating FDR, and the types of elemental composition databases most reliable for searching are discussed. Methodology/Principal Findings The FDR can be determined from one measured value (i.e., the hit rate for search queries) and four parameters determined by Monte Carlo simulation. The results indicate that relatively high FDR values (30–50%) were obtained when searching time-of-flight (TOF)/MS data using the KNApSAcK and KEGG databases. In addition, searches against large all-in-one databases (e.g., PubChem) always produced unacceptable results (FDR >70%). The estimated FDRs suggest that the quality of search results can be improved not only by performing more accurate mass analysis but also by modifying the properties of the compound database. A theoretical analysis indicates that FDR could be improved by using compound database with smaller but higher completeness entries. Conclusions/Significance High accuracy mass analysis, such as Fourier transform (FT)-MS, is needed for reliable annotation (FDR metabolome data. PMID:19847304

Theoretical study of thorium monoxide for the electron electric dipole moment search: electronic properties of H(3)Δ(1) in ThO.

Science.gov (United States)

Skripnikov, L V; Titov, A V

2015-01-14

Recently, improved limits on the electron electric dipole moment, and dimensionless constant, kT,P, characterizing the strength of the T,P-odd pseudoscalar-scalar electron-nucleus neutral current interaction in the H(3)Δ1 state of ThO molecule were obtained by the ACME collaboration [J. Baron et al., Science 343, 269 (2014)]. The interpretation of the experiment in terms of these fundamental quantities is based on the results of theoretical study of appropriate ThO characteristics, the effective electric field acting on electron, Eeff, and a parameter of the T,P-odd pseudoscalar-scalar interaction, WT,P, given in Skripnikov et al. [J. Chem. Phys. 139, 221103 (2013)] by St. Petersburg group. To reduce the uncertainties of the given limits, we report improved calculations of the molecular state-specific quantities Eeff, 81.5 GV/cm, and WT,P, 112 kHz, with the uncertainty within 7% of the magnitudes. Thus, the values recommended to use for the upper limits of the quantities are 75.8 GV/cm and 104 kHz, correspondingly. The hyperfine structure constant, molecule-frame dipole moment of the H(3)Δ1 state, and the H(3)Δ1 → X(1)Σ(+) transition energy which, in general, can serve as a measure of reliability of the obtained Eeff and WT,P values are also calculated. In addition, we report the first calculation of g-factor for the H(3)Δ1 state of ThO. The results are compared to the earlier experimental and theoretical studies, and a detailed analysis of uncertainties of the calculations is given.

Double Stimulation in Strategic Concept Formation: An Activity-Theoretical Analysis of Business Planning in a Small Technology Firm

Science.gov (United States)

Virkkunen, Jaakko; Ristimaki, Paivi

2012-01-01

In this article, we study the relationships between culturally existing general strategy concepts and a small information and communication technology firm's specific strategic challenge in its management team's search for a new strategy concept. We apply three theoretical ideas of cultural historical activity theory: (a) the idea of double…

Theoretical explanations for maintenance of behaviour change: a systematic review of behaviour theories

Science.gov (United States)

Kwasnicka, Dominika; Dombrowski, Stephan U; White, Martin; Sniehotta, Falko

2016-01-01

ABSTRACT Background: Behaviour change interventions are effective in supporting individuals in achieving temporary behaviour change. Behaviour change maintenance, however, is rarely attained. The aim of this review was to identify and synthesise current theoretical explanations for behaviour change maintenance to inform future research and practice. Methods: Potentially relevant theories were identified through systematic searches of electronic databases (Ovid MEDLINE, Embase, PsycINFO). In addition, an existing database of 80 theories was searched, and 25 theory experts were consulted. Theories were included if they formulated hypotheses about behaviour change maintenance. Included theories were synthesised thematically to ascertain overarching explanations for behaviour change maintenance. Initial theoretical themes were cross-validated. Findings: One hundred and seventeen behaviour theories were identified, of which 100 met the inclusion criteria. Five overarching, interconnected themes representing theoretical explanations for behaviour change maintenance emerged. Theoretical explanations of behaviour change maintenance focus on the differential nature and role of motives, self-regulation, resources (psychological and physical), habits, and environmental and social influences from initiation to maintenance. Discussion: There are distinct patterns of theoretical explanations for behaviour change and for behaviour change maintenance. The findings from this review can guide the development and evaluation of interventions promoting maintenance of health behaviours and help in the development of an integrated theory of behaviour change maintenance. PMID:26854092

Intermittent search strategies revisited: effect of the jump length and biased motion

Energy Technology Data Exchange (ETDEWEB)

Rojo, F; Budde, C E [Fa.M.A.F., Universidad Nacional de Cordoba, Ciudad Universitaria, X5000HUA Cordoba (Argentina); Revelli, J; Wio, H S [Instituto de Fisica de Cantabria, Universidad de Cantabria and CSIC, E-39005 Santander (Spain); Oshanin, G [Laboratoire de Physique Theorique de la Matiere Condensee, Universite Pierre et Marie Curie, 4 place Jussieu, 75252 Paris Cedex 5 (France); Lindenberg, Katja [Department of Chemistry and Biochemistry and BioCircuits Institute, University of California, San Diego, La Jolla, CA 92093-0340 (United States)

2010-08-27

We study the kinetics of a search of a single fixed target by a large number of searchers performing an intermittent biased random walk in a homogeneous medium. Our searchers carry out their walks in one of two states between which they switch randomly. One of these states (search phase) is a nearest-neighbor walk characterized by the probability of stepping in a given direction (i.e. the walks in this state are not necessarily isotropic). The other (relocation phase) is characterized by the length of the jumps (i.e. when in this state a walker does not perform a nearest-neighbor walk). Within such a framework, we propose a model to describe the searchers' dynamics, generalizing results of our previous work. We have obtained, and numerically evaluated, analytic results for the mean number of distinct sites visited up to a maximum evolution time. We have studied the dependence of this quantity on both the transition probability between the states and the parameters that characterize each state. In addition to our theoretical approach, we have implemented Monte Carlo simulations, finding excellent agreement between the theoretical-numerical and simulations results.

Intermittent search strategies revisited: effect of the jump length and biased motion

International Nuclear Information System (INIS)

Rojo, F; Budde, C E; Revelli, J; Wio, H S; Oshanin, G; Lindenberg, Katja

2010-01-01

We study the kinetics of a search of a single fixed target by a large number of searchers performing an intermittent biased random walk in a homogeneous medium. Our searchers carry out their walks in one of two states between which they switch randomly. One of these states (search phase) is a nearest-neighbor walk characterized by the probability of stepping in a given direction (i.e. the walks in this state are not necessarily isotropic). The other (relocation phase) is characterized by the length of the jumps (i.e. when in this state a walker does not perform a nearest-neighbor walk). Within such a framework, we propose a model to describe the searchers' dynamics, generalizing results of our previous work. We have obtained, and numerically evaluated, analytic results for the mean number of distinct sites visited up to a maximum evolution time. We have studied the dependence of this quantity on both the transition probability between the states and the parameters that characterize each state. In addition to our theoretical approach, we have implemented Monte Carlo simulations, finding excellent agreement between the theoretical-numerical and simulations results.

Search for the doubly charmed baryon at LHCb

CERN Document Server

Zhong, Liang

The doubly charmed baryon $\\Xi_{cc}^+$, containing two charm quarks, is a baryon predicted by the SU(4) quark model. Experimentally its existence has not been established yet. Many Quantum Chromodynamics (QCD) based theoretical models have predicted its properties with a mass in the range 3500-3700 MeV/$c^2$ and a lifetime in the range 110-250 fs. The experimental searches for the $\\Xi_{cc}^+$ baryon and the measurements of its properties can test these models directly, providing an important input for the understanding of the non-perturbative aspect of QCD. The SELEX collaboration claimed the observation of the $\\Xi_{cc}^+$ baryon in the $\\Xi_{cc}^+ \\to \\Lambda_{c}^+K^-\\pi^+$ decay in 2003. However, the measured lifetime was much shorter than theoretical predictions. Searches for the $\\Xi_{cc}^+$ baryon in the same decay mode by FOCUS, Belle and BaBar experiments failed to reproduce the results. This does not mean that the SELEX result is excluded, however, since production environments at these experi...

Theoretical studies in nuclear reactions and nuclear structure

International Nuclear Information System (INIS)

Wallace, S.J.

1991-05-01

This report discusses topics in the following areas: Hadronic structure; hadrons in nuclei; hot hadronic matter; relativistic nuclear physics and NN interaction; leptonic emissions from high-Z heavy ion collisions; theoretical studies of heavy ion dynamics; nuclear pre-equilibrium reactions; classical chaotic dynamics and nuclear structure; and, theory of nuclear fission

South African Music Studies: Advanced Search

African Journals Online (AJOL)

Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

Journal for Islamic Studies: Advanced Search

African Journals Online (AJOL)

Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

Theoretical Studies on Photoionization Cross Sections of Solid Gold

International Nuclear Information System (INIS)

Ma Xiaoguang; Sun Weiguo; Cheng Yansong

2005-01-01

Accurate expression for photoabsorption (photoionization) cross sections of high density system proposed recently is used to study the photoionization of solid gold. The results show that the present theoretical photoionization cross sections have good agreement both in structure and in magnitude with the experimental results of gold crystal. The studies also indicate that both the real part ε' and the imaginary part ε'' of the complex dielectric constant ε, and the dielectric influence function of a nonideal system have rich structures in low energy side with a range about 50 eV, and suggest that the influence of particle interactions of surrounding particles with the photoionized particle on the photoionization cross sections can be easily investigated using the dielectric influence function. The electron overlap effects are suggested to be implemented in the future studies to improve the accuracy of theoretical photoionization cross sections of a solid system.

Use of Cognitive and Metacognitive Strategies in Online Search: An Eye-Tracking Study

Science.gov (United States)

Zhou, Mingming; Ren, Jing

2016-01-01

This study used eye-tracking technology to track students' eye movements while searching information on the web. The research question guiding this study was "Do students with different search performance levels have different visual attention distributions while searching information online? If yes, what are the patterns for high and low…

Review of the Theoretical and Experimental Status of Dark Matter Identification with Cosmic-Ray Antideuterons

Science.gov (United States)

Aramaki, T.; Boggs, S.; Bufalino, S.; Dal, L.; von Doetinchem, P.; Donato, F.; Fornengo, N.; Fuke, H.; Grefe, M.; Hailey, C.;

Differential Search Coils Based Magnetometers: Conditioning, Magnetic Sensitivity, Spatial Resolution

Directory of Open Access Journals (Sweden)

Timofeeva Maria

2012-03-01

Full Text Available A theoretical and experimental comparison of optimized search coils based magnetometers, operating either in the Flux mode or in the classical Lenz-Faraday mode, is presented. The improvements provided by the Flux mode in terms of bandwidth and measuring range of the sensor are detailed. Theory, SPICE model and measurements are in good agreement. The spatial resolution of the sensor is studied which is an important parameter for applications in non destructive evaluation. A general expression of the magnetic sensitivity of search coils sensors is derived. Solutions are proposed to design magnetometers with reduced weight and volume without degrading the magnetic sensitivity. An original differential search coil based magnetometer, made of coupled coils, operating in flux mode and connected to a differential transimpedance amplifier is proposed. It is shown that this structure is better in terms of volume occupancy than magnetometers using two separated coils without any degradation in magnetic sensitivity. Experimental results are in good agreement with calculations.

Money Inventories in Search Equilibrium

OpenAIRE

Berentsen, Aleksander

1998-01-01

The paper relaxes the one unit storage capacity imposed in the basic search-theoretic model of fiat money with indivisible real commodities and indivisible money. Agents can accumulate as much money as they want. It characterizes the stationary distributions of money and shows that for reasonable parameter values (e.g. production cost, discounting, degree of specialization) a monetary equilibrium exists. There are multiple stationary distributions of a given amount of money, which differ in t...

Discovering How Students Search a Library Web Site: A Usability Case Study.

Science.gov (United States)

Augustine, Susan; Greene, Courtney

2002-01-01

Discusses results of a usability study at the University of Illinois Chicago that investigated whether Internet search engines have influenced the way students search library Web sites. Results show students use the Web site's internal search engine rather than navigating through the pages; have difficulty interpreting library terminology; and…

More Jets in more LHC Searches

CERN Document Server

Schichtel, Peter

Multi jet observables are a powerful tool to new physics as well as a boost to standard analysis strategies. We show their use in a reasonably model independent dark matter search and a jet veto Higgs analysis. We nd however that, these observables are plagued by huge theoretical uncertainties connected to unphysical scale parameters. In the democratic limit we compute analytically the all order resummed jet spectrum at leading log. It obeys so called staircase scaling. With the help of state of the art Monte Carlo tools we study the jet spectrum features in great detail. In addition we also study so called Poisson scaling. This allows us to develop a data driven strategy to x the standard model multi jet backgrounds.

A review of the reporting of web searching to identify studies for Cochrane systematic reviews.

Science.gov (United States)

Briscoe, Simon

2018-03-01

The literature searches that are used to identify studies for inclusion in a systematic review should be comprehensively reported. This ensures that the literature searches are transparent and reproducible, which is important for assessing the strengths and weaknesses of a systematic review and re-running the literature searches when conducting an update review. Web searching using search engines and the websites of topically relevant organisations is sometimes used as a supplementary literature search method. Previous research has shown that the reporting of web searching in systematic reviews often lacks important details and is thus not transparent or reproducible. Useful details to report about web searching include the name of the search engine or website, the URL, the date searched, the search strategy, and the number of results. This study reviews the reporting of web searching to identify studies for Cochrane systematic reviews published in the 6-month period August 2016 to January 2017 (n = 423). Of these reviews, 61 reviews reported using web searching using a search engine or website as a literature search method. In the majority of reviews, the reporting of web searching was found to lack essential detail for ensuring transparency and reproducibility, such as the search terms. Recommendations are made on how to improve the reporting of web searching in Cochrane systematic reviews. Copyright © 2017 John Wiley & Sons, Ltd.

University Students' Online Information Searching Strategies in Different Search Contexts

Science.gov (United States)

Tsai, Meng-Jung; Liang, Jyh-Chong; Hou, Huei-Tse; Tsai, Chin-Chung

2012-01-01

This study investigates the role of search context played in university students' online information searching strategies. A total of 304 university students in Taiwan were surveyed with questionnaires in which two search contexts were defined as searching for learning, and searching for daily life information. Students' online search strategies…

Colleagues and Competitors: How Internal Social Comparisons Shape Organizational Search and Adaptation

DEFF Research Database (Denmark)

Baumann, Oliver; Eggers, JP; Stieglitz, Nils

2018-01-01

Intra-organizational comparisons—managers and units benchmarking their performance against each other—can turn colleagues into competitors. To better understand when organizations should allow or even encourage internal social comparisons, we study their implications for organizational adaptation....... We highlight empirical implications and discuss theoretical links to work on intra-organizational competition, social comparisons and aspiration-driven search, diversification and performance, and the adaptation of multi-business firms....

MINOS Sterile Neutrino Search

Energy Technology Data Exchange (ETDEWEB)

Koskinen, David Jason [Univ. College London, Bloomsbury (United Kingdom)

2009-02-01

The Main Injector Neutrino Oscillation Search (MINOS) is a long-baseline accelerator neutrino experiment designed to measure properties of neutrino oscillation. Using a high intensity muon neutrino beam, produced by the Neutrinos at Main Injector (NuMI) complex at Fermilab, MINOS makes two measurements of neutrino interactions. The first measurement is made using the Near Detector situated at Fermilab and the second is made using the Far Detector located in the Soudan Underground laboratory in northern Minnesota. The primary goal of MINOS is to verify, and measure the properties of, neutrino oscillation between the two detectors using the v _μ→ V_τ transition. A complementary measurement can be made to search for the existence of sterile neutrinos; an oft theorized, but experimentally unvalidated particle. The following thesis will show the results of a sterile neutrino search using MINOS RunI and RunII data totaling ~2.5 x 10²⁰ protons on target. Due to the theoretical nature of sterile neutrinos, complete formalism that covers transition probabilities for the three known active states with the addition of a sterile state is also presented.

Theoretical study of near-threshold electron-molecule scattering

International Nuclear Information System (INIS)

Morrison, M.A.

1989-01-01

We have been engaged in carrying out a foundation study on problems pertaining to near-threshold nuclear excitations in e-H 2 scattering. The primary goals of this study are: to investigate the severity and nature of the anticipated breakdown of the adiabatic-nuclei (AN) approximation, first for rotation only (in the rigid-rotator approximation), and then for vibration; to determine a data base of accurate ab initio cross sections for this important system; to implement and test accurate, computationally-tractable model potentials for exchange and polarization effects; and to begin the exploration of alternative scattering theories for near-threshold collisions. This study has provided a well-defined theoretical context for our future investigations. Second, it has enabled us to identify and quantify several serious problems in the theory of near-threshold electron-molecule scattering that demand attention. And finally, it has led to the development of some of the theoretical and computational apparatus that will form the foundation of future work. In this report, we shall review our progress to date, emphasizing work completed during the current contract year. 17 refs., 5 figs., 1 tab

Visual search of illusory contours: Shape and orientation effects

Directory of Open Access Journals (Sweden)

Gvozdenović Vasilije

2008-01-01

Full Text Available Illusory contours are specific class of visual stimuli that represent stimuli configurations perceived as integral irrespective of the fact that they are given in fragmented uncompleted wholes. Due to their specific features, illusory contours gained much attention in last decade representing prototype of stimuli used in investigations focused on binding problem. On the other side, investigations of illusory contours are related to problem of the level of their visual processing. Neurophysiologic studies show that processing of illusory contours proceed relatively early, on the V2 level, on the other hand most of experimental studies claim that illusory contours are perceived with engagement of visual attention, binding their elements to whole percept. This research is focused on two experiments in which visual search of illusory contours are based on shape and orientation. The main experimental procedure evolved the task proposed by Bravo and Nakayama where instead of detection, subjects were performing identification of one among two possible targets. In the first experiment subjects detected the presence of illusory square or illusory triangle, while in the second experiment subject were detecting two different orientations of illusory triangle. The results are interpreted in terms of visual search and feature integration theory. Beside the type of visual search task, search type proved to be dependent of specific features of illusory shapes which further complicate theoretical interpretation of the level of their perception.

How do small groups make decisions? : A theoretical framework to inform the implementation and study of clinical competency committees.

Science.gov (United States)

Chahine, Saad; Cristancho, Sayra; Padgett, Jessica; Lingard, Lorelei

2017-06-01

In the competency-based medical education (CBME) approach, clinical competency committees are responsible for making decisions about trainees' competence. However, we currently lack a theoretical model for group decision-making to inform this emerging assessment phenomenon. This paper proposes an organizing framework to study and guide the decision-making processes of clinical competency committees.This is an explanatory, non-exhaustive review, tailored to identify relevant theoretical and evidence-based papers related to small group decision-making. The search was conducted using Google Scholar, Web of Science, MEDLINE, ERIC, and PsycINFO for relevant literature. Using a thematic analysis, two researchers (SC & JP) met four times between April-June 2016 to consolidate the literature included in this review.Three theoretical orientations towards group decision-making emerged from the review: schema, constructivist, and social influence. Schema orientations focus on how groups use algorithms for decision-making. Constructivist orientations focus on how groups construct their shared understanding. Social influence orientations focus on how individual members influence the group's perspective on a decision. Moderators of decision-making relevant to all orientations include: guidelines, stressors, authority, and leadership.Clinical competency committees are the mechanisms by which groups of clinicians will be in charge of interpreting multiple assessment data points and coming to a shared decision about trainee competence. The way in which these committees make decisions can have huge implications for trainee progression and, ultimately, patient care. Therefore, there is a pressing need to build the science of how such group decision-making works in practice. This synthesis suggests a preliminary organizing framework that can be used in the implementation and study of clinical competency committees.

Theoretical bases of individualization of training in wrestling

Directory of Open Access Journals (Sweden)

S.V. Latyshev

2013-04-01

Full Text Available Theoretical bases of individualization of training in wrestling are developed. They include the structure of organization of research, positions of conception, system of individualization of training. The system of individualization of training is designed as an aggregate of elements and subsystems, which guided mutually assist an exposure, forming, development and perfection of own style of opposing. It is marked that in the system of training activity substantially more attention is spared development of the special endurance and attended directed qualities. In the system of after training and after a competition activity an accent was displaced toward the search of facilities of more effective renewal and stimulation of the special capacity, search of new optimum rations of feed and new food additions, search of new methods of decline of weight of fighters. Tactic of conduct of duels changed in the system of competition activity, which foresees yet more rational and economy expense of energy in a fight and in a competition on the whole.

Exotic particle searches using the Purdue AMS facility

International Nuclear Information System (INIS)

Javorsek, D. II; Elmore, D.; Fischbach, E.; Miller, T.

2001-01-01

Two exotic particle searches are being performed using the Accelerator Mass Spectrometer (AMS) at the Purdue Rare Isotope Measurement Laboratory (PRIME Lab). Recent theoretical developments allow for the possibility of small violations of the symmetrization postulate, which may lead in turn to detectable violations of the Pauli exclusion principle. We report the results of a new experimental search for paronic (Pauli-violating) Be, denoted by Be', in samples where Be' retention would be highest. Our limits represent an improvement by a factor of approximately 300 over a previous search for Be'. There are also several recent cosmological motivations for strongly interacting massive particles (SIMPs). We present results from our current search for anomalous heavy isotopes of Au in samples of Australian and laboratory gold with a limit on SIMP abundance ratios as low as 10 -12 . This experiment provides significant constraints on the existence of such particles in high Z nuclei

PREFACE: The random search problem: trends and perspectives The random search problem: trends and perspectives

Science.gov (United States)

da Luz, Marcos G. E.; Grosberg, Alexander; Raposo, Ernesto P.; Viswanathan, Gandhi M.

2009-10-01

`I can't find my keys!' Who hasn't gone through this experience when leaving, in a hurry, to attend to some urgent matter? The keys could be in many different places. Unless one remembers where he or she has left the keys, the only solution is to look around, more or less randomly. Random searches are common because in many cases the locations of the specific targets are not known a priori. Indeed, such problems have been discussed in diverse contexts, attracting the interest of scientists from many fields, for example: the dynamical or stochastic search for a stable minimum in a complex energy landscape, relevant to systems such as glasses, protein (folding), and others; oil recovery from mature reservoirs; proteins searching for their specific target sites on DNA; animal foraging; survival at the edge of extinction due to low availability of energetic resources; automated searches of registers in high-capacity databases, search engine (e.g., `crawlers') that explore the internet; and even pizza delivery in a jammed traffic system of a medium-size town. In this way, the subject is interesting, challenging and has recently become an important scientific area of investigation. Although the applications are diverse, the underlying physical mechanisms are the same which will become clear in this special issue. Moreover, the inherent complexity of the problem, the abundance of ideas and methods found in this growing interdisciplinary field of research is studied in many areas of physics. In particular, the concepts and methods of statistical mechanics are particularly useful to the study of random searches. On one hand, it centres on how to find the global or local maxima of search efficiency functions with incomplete information. This is, of course, related to the long tradition in physics of using different conceptual and mathematical tools, such as variational methods, to extremize relevant quantities, e.g., energy, entropy and action. Such ideas and approaches are

Theoretical Studies of Elementary Hydrocarbon Species and Their Reactions

Energy Technology Data Exchange (ETDEWEB)

Allen, Wesley D. [Univ. of Georgia, Athens, GA (United States). Dept. of Chemistry. Center for Computational Quantum Chemistry; Schaefer, III, Henry F. [Univ. of Georgia, Athens, GA (United States). Dept. of Chemistry. Center for Computational Quantum Chemistry

2015-11-14

This is the final report of the theoretical studies of elementary hydrocarbon species and their reactions. Part A has a bibliography of publications supported by DOE from 2010 to 2016 and Part B goes into recent research highlights.

Comparative Study on Three Major Internet Search Engines ...

African Journals Online (AJOL)

, Google and ask.com search engines. Experimental method was used with ten reference questions which were used to query each of the search engines . Yahoo obtained the highest results (521,801,043) among the three Web search ...

ACCOUNTING FOR USERS' INFLATED ASSESSMENTS OF ONLINE CATALOG SEARCH PERFORMANCE AND USEFULNESS: AN EXPERIMENTAL STUDY

Directory of Open Access Journals (Sweden)

Charles R. Hildreth

2001-01-01

Full Text Available User-oriented approaches to information retrieval (IR system performance evaluation assign a major role to user satisfaction with search results and overall system performance. Expressed satisfaction with search results is often used as a measure of utility. Many research studies indicate that users of on-line library catalogs (OPACs and other IR systems often express satisfaction with poor search results. This phenomenon of "false positives," inflated assessments of search results and system performance, has not been adequately explained. Non-performance factors such as interface style and ease of use may have an affect on a searcher's satisfaction with search results. The research described in this report investigates this phenomenon. This paper presents the findings of an experimental study which compared users' search performance and assessments of ease of use, system usefulness, and satisfaction with search results after use of a Web OPAC or its conventional counterpart. The primary questions addressed by this research center on the influence of two experimental factors, OPAC search interface style and search task level of difficulty, on the dependent variables: actual search performance, perceptions of ease of use and system usefulness, and assessments of satisfaction with search results. The study also investigated associations between perceived ease of use, system usefulness, and satisfaction with search results. Lastly, the study looked for associations between the dependent variables and personal characteristics. No association was found between satisfaction with search results and actual search performance. Web OPAC searchers outperformed Text OPAC searchers, but search task level of difficulty is a major determinant of search success. A strong positive correlation was found between perceptions of system ease of use and assessments of search results.

Protocol: a systematic review of studies developing and/or evaluating search strategies to identify prognosis studies.

Science.gov (United States)

Corp, Nadia; Jordan, Joanne L; Hayden, Jill A; Irvin, Emma; Parker, Robin; Smith, Andrea; van der Windt, Danielle A

2017-04-20

Prognosis research is on the rise, its importance recognised because chronic health conditions and diseases are increasingly common and costly. Prognosis systematic reviews are needed to collate and synthesise these research findings, especially to help inform effective clinical decision-making and healthcare policy. A detailed, comprehensive search strategy is central to any systematic review. However, within prognosis research, this is challenging due to poor reporting and inconsistent use of available indexing terms in electronic databases. Whilst many published search filters exist for finding clinical trials, this is not the case for prognosis studies. This systematic review aims to identify and compare existing methodological filters developed and evaluated to identify prognosis studies of any of the three main types: overall prognosis, prognostic factors, and prognostic [risk prediction] models. Primary studies reporting the development and/or evaluation of methodological search filters to retrieve any type of prognosis study will be included in this systematic review. Multiple electronic bibliographic databases will be searched, grey literature will be sought from relevant organisations and websites, experts will be contacted, and citation tracking of key papers and reference list checking of all included papers will be undertaken. Titles will be screened by one person, and abstracts and full articles will be reviewed for inclusion independently by two reviewers. Data extraction and quality assessment will also be undertaken independently by two reviewers with disagreements resolved by discussion or by a third reviewer if necessary. Filters' characteristics and performance metrics reported in the included studies will be extracted and tabulated. To enable comparisons, filters will be grouped according to database, platform, type of prognosis study, and type of filter for which it was intended. This systematic review will identify all existing validated

Internet search and krokodil in the Russian Federation: an infoveillance study.

Science.gov (United States)

Zheluk, Andrey; Quinn, Casey; Meylakhs, Peter

2014-09-18

Krokodil is an informal term for a cheap injectable illicit drug domestically prepared from codeine-containing medication (CCM). The method of krokodil preparation may produce desomorphine as well as toxic reactants that cause extensive tissue necrosis. The first confirmed report of krokodil use in Russia took place in 2004. In 2012, reports of krokodil-related injection injuries began to appear beyond Russia in Western Europe and the United States. This exploratory study had two main objectives: (1) to determine if Internet search patterns could detect regularities in behavioral responses to Russian CCM policy at the population level, and (2) to determine if complementary data sources could explain the regularities we observed. First, we obtained krokodil-related search pattern data for each Russia subregion (oblast) between 2011 and 2012. Second, we analyzed several complementary data sources included krokodil-related court cases, and related search terms on both Google and Yandex to evaluate the characteristics of terms accompanying krokodil-related search queries. In the 6 months preceding CCM sales restrictions, 21 of Russia's 83 oblasts had search rates higher than the national average (mean) of 16.67 searches per 100,000 population for terms associated with krokodil. In the 6 months following restrictions, mean national searches dropped to 9.65 per 100,000. Further, the number of oblasts recording a higher than average search rate dropped from 30 to 16. Second, we found krokodil-related court appearances were moderately positively correlated (Spearman correlation=.506, P≤.001) with behaviors consistent with an interest in the production and use of krokodil across Russia. Finally, Google Trends and Google and Yandex related terms suggested consistent public interest in the production and use of krokodil as well as for CCM as analgesic medication during the date range covered by this study. Illicit drug use data are generally regarded as difficult to obtain

Searching possibilities of a composite structure of quarks from the jet studies in the ATLAS experiment: physical and experimental aspects

International Nuclear Information System (INIS)

Brette, Ph.

1996-01-01

This thesis presents the searching possibilities of a composite structure of quark from the jet studies in the ATLAS experiment. ATLAS is one of the major detectors on the LHC, the next proton-proton collider at CERN. The general physic framework of the quark compositeness is first introduced, the its expected search from the contact terms in the channel 2 → 2 is explained. After a description of the ATLAS apparatus and of the prototype of the hadronic scintillating tiles calorimeter, various experimental properties of the hadron calorimeter with respect to the jet measurement are studied. The effect of the non-linearity of the calorimeter response is particularly discussed, including the light red out with the photomultipliers. The laser monitoring system enables a full control of the gain stability of the photomultipliers and of their non-linearity for large signals. Its design and the measured performance are shown. Finally, by considering both the expected performances of the ATLAS detector and the theoretical uncertainties, it appears that the compositeness scale controlled at the LHC, for quarks, should reach 15 to 20 TeV depending upon the luminosity, from jet measurement up to 3 TeV. (author)

Towards a methodology for cluster searching to provide conceptual and contextual "richness" for systematic reviews of complex interventions: case study (CLUSTER).

Science.gov (United States)

Booth, Andrew; Harris, Janet; Croot, Elizabeth; Springett, Jane; Campbell, Fiona; Wilkins, Emma

2013-09-28

Systematic review methodologies can be harnessed to help researchers to understand and explain how complex interventions may work. Typically, when reviewing complex interventions, a review team will seek to understand the theories that underpin an intervention and the specific context for that intervention. A single published report from a research project does not typically contain this required level of detail. A review team may find it more useful to examine a "study cluster"; a group of related papers that explore and explain various features of a single project and thus supply necessary detail relating to theory and/or context.We sought to conduct a preliminary investigation, from a single case study review, of techniques required to identify a cluster of related research reports, to document the yield from such methods, and to outline a systematic methodology for cluster searching. In a systematic review of community engagement we identified a relevant project - the Gay Men's Task Force. From a single "key pearl citation" we conducted a series of related searches to find contextually or theoretically proximate documents. We followed up Citations, traced Lead authors, identified Unpublished materials, searched Google Scholar, tracked Theories, undertook ancestry searching for Early examples and followed up Related projects (embodied in the CLUSTER mnemonic). Our structured, formalised procedure for cluster searching identified useful reports that are not typically identified from topic-based searches on bibliographic databases. Items previously rejected by an initial sift were subsequently found to inform our understanding of underpinning theory (for example Diffusion of Innovations Theory), context or both. Relevant material included book chapters, a Web-based process evaluation, and peer reviewed reports of projects sharing a common ancestry. We used these reports to understand the context for the intervention and to explore explanations for its relative

Theoretical modelling of semiconductor surfaces microscopic studies of electrons and photons

CERN Document Server

Srivastava, G P

1999-01-01

The state-of-the-art theoretical studies of ground state properties, electronic states and atomic vibrations for bulk semiconductors and their surfaces by the application of the pseudopotential method are discussed. Studies of bulk and surface phonon modes have been extended by the application of the phenomenological bond charge model. The coverage of the material, especially of the rapidly growing and technologically important topics of surface reconstruction and chemisorption, is up-to-date and beyond what is currently available in book form. Although theoretical in nature, the book provides

How Users Search the Library from a Single Search Box

Science.gov (United States)

Lown, Cory; Sierra, Tito; Boyer, Josh

2013-01-01

Academic libraries are turning increasingly to unified search solutions to simplify search and discovery of library resources. Unfortunately, very little research has been published on library user search behavior in single search box environments. This study examines how users search a large public university library using a prominent, single…

Bioactivity of Isoflavones: Assessment through a Theoretical Model as a Way to Obtain a “Theoretical Efficacy Related to Estradiol (TERE)”

Science.gov (United States)

Campos, Maria da Graça R.; Matos, Miguel Pires

2010-01-01

The increase of human life span will have profound implications in Public Health in decades to come. By 2030, there will be an estimated 1.2 billion women in post-menopause. Hormone Replacement Therapy with synthetic hormones is still full of risks and according to the latest developments, should be used for the shortest time possible. Searching for alternative drugs is inevitable in this scenario and science must provide physicians with other substances that can be used to treat the same symptoms with less side effects. Systematic research carried out on this field of study is focusing now on isoflavones but the randomised controlled trials and reviews of meta-analysis concerning post-menopause therapy, that could have an important impact on human health, are very controversial. The aim of the present work was to establish a theoretical calculation suitable for use as a way to estimate the “Theoretical Efficacy (TE)” of a mixture with different bioactive compounds as a way to obtain a “Theoretical Efficacy Related to Estradiol (TERE)”. The theoretical calculation that we propose in this paper integrates different knowledge about this subject and sets methodological boundaries that can be used to analyse already published data. The outcome should set some consensus for new clinical trials using isoflavones (isolated or included in mixtures) that will be evaluated to assess their therapeutically activity. This theoretical method for evaluation of a possible efficacy could probably also be applied to other herbal drug extracts when a synergistic or contradictory bio-effect is not verified. In this way, it we may contribute to enlighten and to the development of new therapeutic approaches. PMID:20386649

Public administration and R&D localisation by pharmaceutical and biotech companies: a theoretical framework and the Italian case-study.

Science.gov (United States)

Jommi, Claudio; Paruzzolo, Silvia

2007-04-01

This article has two objectives. It firstly provides a general framework for variables that influence R&D (Research and Development) localisation by pharmaceutical and biotech companies. The analysis of R&D localization includes both in-house R&D and contracted R&D. Following a systematic literature search, these variables were classified into four distinct categories: regulatory environment, institutional framework, national systems of innovation and local development and specialisation. The authors highlight that some of these factors directly depend on the action of public administrations (e.g., patent protection, price regulation, public investments in research, and incentives to private companies); others are indirectly influenced by public policies (e.g., GDP growth rate, infrastructures). This theoretical framework was used to analyse the Italian case-study. Pros and cons of the Italian context were investigated from the point of view of multinational pharmaceutical companies and the Italian Association of Biotech Companies. Interviews were chosen as the most appropriate data gathering technique given the exploratory nature of the study of the Italian context. The paper is divided into five parts. A brief introduction provides figures showing that Europe has been loosing positions compared with other Continents and the same has occurred in Italy compared with other EU countries. The second one illustrates the methodology. The third one is focused on variables affecting R&D localisation. In the fourth section the Italian case-study is discussed. Theoretical and empirical findings are summarised and discussed in the conclusions.

Enhancing search efficiency by means of a search filter for finding all studies on animal experimentation in PubMed.

Science.gov (United States)

Hooijmans, Carlijn R; Tillema, Alice; Leenaars, Marlies; Ritskes-Hoitinga, Merel

2010-07-01

Collecting and analysing all available literature before starting an animal experiment is important and it is indispensable when writing a systematic review (SR) of animal research. Writing such review prevents unnecessary duplication of animal studies and thus unnecessary animal use (Reduction). One of the factors currently impeding the production of 'high-quality' SRs in laboratory animal science is the fact that searching for all available literature concerning animal experimentation is rather difficult. In order to diminish these difficulties, we developed a search filter for PubMed to detect all publications concerning animal studies. This filter was compared with the method most frequently used, the PubMed Limit: Animals, and validated further by performing two PubMed topic searches. Our filter performs much better than the PubMed limit: it retrieves, on average, 7% more records. Other important advantages of our filter are that it also finds the most recent records and that it is easy to use. All in all, by using our search filter in PubMed, all available literature concerning animal studies on a specific topic can easily be found and assessed, which will help in increasing the scientific quality and thereby the ethical validity of animal experiments.

Theoretical nuclear reaction and structure studies using hyperons and photons

International Nuclear Information System (INIS)

Cotanch, S.R.

1991-01-01

This report details research progress and results obtained during the 12 month period from January 1991 through 31 December 1991. The research project, entitled ''Theoretical Nuclear Reaction and Structure Studies Using Hyperons and Photons,'' is supported by grant DE-FG05-88ER40461 between North Carolina State University and the United States Department of Energy. In compliance with grant requirements the Principal Investigator, Professor Stephen R. Cotanch, has conducted a research program addressing theoretical investigations of reactions involving hyperons and photons. The new, significant research results are briefly summarized in the following sections

Stochastic optimal foraging: tuning intensive and extensive dynamics in random searches.

Directory of Open Access Journals (Sweden)

Frederic Bartumeus

Full Text Available Recent theoretical developments had laid down the proper mathematical means to understand how the structural complexity of search patterns may improve foraging efficiency. Under information-deprived scenarios and specific landscape configurations, Lévy walks and flights are known to lead to high search efficiencies. Based on a one-dimensional comparative analysis we show a mechanism by which, at random, a searcher can optimize the encounter with close and distant targets. The mechanism consists of combining an optimal diffusivity (optimally enhanced diffusion with a minimal diffusion constant. In such a way the search dynamics adequately balances the tension between finding close and distant targets, while, at the same time, shifts the optimal balance towards relatively larger close-to-distant target encounter ratios. We find that introducing a multiscale set of reorientations ensures both a thorough local space exploration without oversampling and a fast spreading dynamics at the large scale. Lévy reorientation patterns account for these properties but other reorientation strategies providing similar statistical signatures can mimic or achieve comparable efficiencies. Hence, the present work unveils general mechanisms underlying efficient random search, beyond the Lévy model. Our results suggest that animals could tune key statistical movement properties (e.g. enhanced diffusivity, minimal diffusion constant to cope with the very general problem of balancing out intensive and extensive random searching. We believe that theoretical developments to mechanistically understand stochastic search strategies, such as the one here proposed, are crucial to develop an empirically verifiable and comprehensive animal foraging theory.

The method of search of tendencies

International Nuclear Information System (INIS)

Reuss, Paul.

1981-08-01

The search of tendencies is an application of the mean squares method. Its objective is the better possible evaluation of the basic data used in the calculations from the comparison between measurements of integral characteristics and the corresponding theoretical results. This report presents the minimization which allows the estimation of the basic data and, above all, the methods which are necessary for the critical analysis of the obtained results [fr

Theoretical study of n-alkane adsorption on metal surfaces

DEFF Research Database (Denmark)

Morikawa, Yoshitada; Ishii, Hisao; Seki, Kazuhiko

2004-01-01

The interaction between n-alkane and metal surfaces has been studied by means of density-functional theoretical calculations within a generalized gradient approximation (GGA). We demonstrate that although the GGA cannot reproduce the physisorption energy well, our calculations can reproduce the e...

Theoretical rationale for music selection in oncology intervention research: an integrative review.

Science.gov (United States)

Burns, Debra S

2012-01-01

Music-based interventions have helped patients with cancer improve their quality of life, decrease treatment related distress, and manage pain. However, quantitative findings from music intervention studies are inconsistent. The purpose of this review was to explore the theoretical underpinnings for the selection of the music stimuli used to influence targeted outcomes. It was hypothesized that disparate findings were due in part to the atheoretical nature of music selection and the resulting diversity in music stimuli between and within studies. A systematic research synthesis including a comprehensive database and reference list search resulted in 22 studies. Included studies were compiled into two tables cataloging intervention theory, intervention content, and outcomes. A majority of studies did not provide a rationale or intervention theory for the delivery of music or choice of outcomes. Recorded music was the most common delivery method, but the specific music was rarely included within the report. Only two studies that included a theoretical framework reported null results on at least some of the outcomes. Null results are partially explained by an incomplete or mismatch in intervention theory and music selection and delivery. While the inclusion of an intervention theory does not guarantee positive results, including a theoretical rationale for the use of music, particular therapeutic processes or mechanisms, and the specifics of how music is selected and delivered increases scientific rigor and the probability of clinical translation.

Tales from the Field: Search Strategies Applied in Web Searching

Directory of Open Access Journals (Sweden)

Soohyung Joo

2010-08-01

Full Text Available In their web search processes users apply multiple types of search strategies, which consist of different search tactics. This paper identifies eight types of information search strategies with associated cases based on sequences of search tactics during the information search process. Thirty-one participants representing the general public were recruited for this study. Search logs and verbal protocols offered rich data for the identification of different types of search strategies. Based on the findings, the authors further discuss how to enhance web-based information retrieval (IR systems to support each type of search strategy.

Theoretical pluralism in psychoanalytic case studies.

Science.gov (United States)

Willemsen, Jochem; Cornelis, Shana; Geerardyn, Filip M; Desmet, Mattias; Meganck, Reitske; Inslegers, Ruth; Cauwe, Joachim M B D

2015-01-01

The aim of this study is to provide an overview of the scientific activity of different psychoanalytic schools of thought in terms of the content and production of case studies published on ISI Web of Knowledge. Between March 2013 and November 2013, we contacted all case study authors included in the online archive of psychoanalytic and psychodynamic case studies (www.singlecasearchive.com) to inquire about their psychoanalytic orientation during their work with the patient. The response rate for this study was 45%. It appears that the two oldest psychoanalytic schools, Object-relations psychoanalysis and Ego psychology or "Classical psychoanalysis" dominate the literature of published case studies. However, most authors stated that they feel attached to two or more psychoanalytic schools of thought. This confirms that the theoretical pluralism in psychoanalysis stretches to the field of single case studies. The single case studies of each psychoanalytic school are described separately in terms of methodology, patient, therapist, or treatment features. We conclude that published case studies features are fairly similar across different psychoanalytic schools. The results of this study are not representative of all psychoanalytic schools, as some do not publish their work in ISI ranked journals.

Theoretical pluralism in psychoanalytic case studies

Science.gov (United States)

Willemsen, Jochem; Cornelis, Shana; Geerardyn, Filip M.; Desmet, Mattias; Meganck, Reitske; Inslegers, Ruth; Cauwe, Joachim M. B. D.

2015-01-01

The aim of this study is to provide an overview of the scientific activity of different psychoanalytic schools of thought in terms of the content and production of case studies published on ISI Web of Knowledge. Between March 2013 and November 2013, we contacted all case study authors included in the online archive of psychoanalytic and psychodynamic case studies (www.singlecasearchive.com) to inquire about their psychoanalytic orientation during their work with the patient. The response rate for this study was 45%. It appears that the two oldest psychoanalytic schools, Object-relations psychoanalysis and Ego psychology or “Classical psychoanalysis” dominate the literature of published case studies. However, most authors stated that they feel attached to two or more psychoanalytic schools of thought. This confirms that the theoretical pluralism in psychoanalysis stretches to the field of single case studies. The single case studies of each psychoanalytic school are described separately in terms of methodology, patient, therapist, or treatment features. We conclude that published case studies features are fairly similar across different psychoanalytic schools. The results of this study are not representative of all psychoanalytic schools, as some do not publish their work in ISI ranked journals. PMID:26483725

The Ulam Index: Methods of Theoretical Computer Science Help in Identifying Chemical Substances

Science.gov (United States)

Beltran, Adriana; Salvador, James

1997-01-01

In this paper, we show how methods developed for solving a theoretical computer problem of graph isomorphism are used in structural chemistry. We also discuss potential applications of these methods to exobiology: the search for life outside Earth.

Using a Google Search Appliance (GSA to search digital library collections: a case study of the INIS Collection Search

Directory of Open Access Journals (Sweden)

Dobrica Savic

2014-05-01

The International Nuclear Information System (INIS hosts one of the world’s largest collections of published information on the peaceful uses of nuclear science and technology. It offers online access to a unique collection of 3.6 million bibliographic records and 320,000 full-texts of non-conventional (grey literature. This large digital library collection suffered from most of the well-known shortcomings of the classic library catalogue. Searching was complex and complicated, required some training in using Boolean logic, full-text searching was not an option, and the response time was slow. An opportune moment came with the retirement of the previous catalogue software and with the adoption of Google Search Appliance (GSA as an organization-wide search engine standard. INIS was quick to realize a great potential in using such a well-known application as a replacement for its online catalogue and this paper presents the advantages and disadvantages encountered during three years of GSA use. Based on specific INIS-based practice and experience, this paper also offers some guidelines on ways to improve classic collections of millions of bibliographic and full-text documents, while achieving multiple benefits such as increased use, accessibility, usability, expandability and improving the user search and retrieval experience.

One-shot service searches: Preprint repositories at a mouseclick

Energy Technology Data Exchange (ETDEWEB)

Canessa, E [International Centre for Theoretical Physics, Trieste (Italy); Pastore, G [Trieste Univ., Trieste (Italy). Dipt. di Fisica

1996-09-01

In this article we introduce the ICTP-International Centre for Theoretical Physics`s prototype for a ``One-Shot World-Wide Preprints Search`` on the Web. This is a new centralized interface for a global search throughout the most popular scientific preprint repositories. Herein, we briefly discuss our experience with the implementation of this service and propose it as a possible alternative solution to the problem of getting access to the information without being either overloaded with lots of new documents or not being informed at all. (author). 13 refs, 3 figs.

One-shot service searches: Preprint repositories at a mouseclick

International Nuclear Information System (INIS)

Canessa, E.; Pastore, G.

1996-09-01

In this article we introduce the ICTP-International Centre for Theoretical Physics's prototype for a ''One-Shot World-Wide Preprints Search'' on the Web. This is a new centralized interface for a global search throughout the most popular scientific preprint repositories. Herein, we briefly discuss our experience with the implementation of this service and propose it as a possible alternative solution to the problem of getting access to the information without being either overloaded with lots of new documents or not being informed at all. (author). 13 refs, 3 figs

Chapter 2: Theoretical Models for Understanding Physical Activity Behavior among Children and Adolescents--Social Cognitive Theory and Self-Determination Theory

Science.gov (United States)

Motl, Robert W.

2007-01-01

The study of physical activity behavior in youth generally lacks a sufficient theoretical foundation for examining variables that influence that behavior. This is a major limitation because theory guides the search for determinants of behavior and the subsequent interplay between research findings and application. Theory offers a systematically…

Green Product Purchasing Phenomenon: Exploring The Gaps Of Theoretical, Methodological And Empirical

Directory of Open Access Journals (Sweden)

Rahab Bin Tafsir

2016-12-01

Full Text Available This study aims to identify research gaps on green purchasing topics and proposes several recommendations for future research. To explain the phenomenon of green products  purchase, this study uses Theory of Planned Behavior (TPB in framework. The research uses a  qualitative method approach by conducting a review of articles that traced through four popular journal providers: Ebsco, J-Stors, Proquest and Emeraldinsight. A literature search process held between April, 2015 until Juni, 2015 and resulted on 67 chosen articles. The outcome of the review identified four theoretical gaps, two  methodological gaps and one practical gap.

Complementarity of WIMP Sensitivity with direct SUSY, Monojet and Dark Matter Searches in the MSSM

CERN Document Server

Arbey, Alexandre; Mahmoudi, Farvah

2014-01-01

This letter presents new results on the combined sensitivity of the LHC and underground dark matter search experiments to the lightest neutralino as WIMP candidate in the minimal Supersymmetric extension of the Standard Model. We show that monojet searches significantly extend the sensitivity to the neutralino mass in scenarios where scalar quarks are nearly degenerate in mass with it. The inclusion of the latest bound by the LUX experiment on the neutralino-nucleon spin-independent scattering cross section expands this sensitivity further, highlighting the remarkable complementarity of jets/$\\ell$s+MET and monojet at LHC and dark matter searches in probing models of new physics with a dark matter candidate. The qualitative results of our study remain valid after accounting for theoretical uncertainties.

Search for New and Unusual Strangeonia using CLAS

Energy Technology Data Exchange (ETDEWEB)

Saini, Mukesh Satyapraka [Florida State Univ., Tallahassee, FL (United States)

2013-03-12

We perform a survey of the proton, K⁺, K^- -3 charged track data, taken by the CLAS detector for the HyCLAS experiment during the g12 run-period at Jefferson Lab. We aim to study the strong decay amplitudes, partial widths and production channels of strangeonia from the CLAS g12 dataset. HyCLAS was motivated by the experimental results for gluonic hybrid meson candidates, theoretical Lattice QCD, and Flux-tube Model calculations and predictions. The experiment was designed and conducted to search and observe new forms of hadronic matter through photoproduction.

Search for new heavy techniparticles

International Nuclear Information System (INIS)

Baltay, C.; Gordon, H.

1982-01-01

In this article, the authors consider in some detail an experiment to search for the Technieta (/sub eta T/), which is expected to be in the 100 to 300 GeV mass range. For the sake of concreteness they use the predictions of the technicolor models; however, it might be better to think of these considerations as an example of the kind of searches that should be carried out with the next generation of hadron-hadron colliders, without putting too much importance on the details of the theoretical models that happen to be in fashion at this time. The general notion of a -- TeV mass scale and the rough value of the coupling strengths of the new mass scale to the present quarks, leptons and gluons seem more reliable than details of the particular models

Theoretical study of rock mass investigation efficiency

International Nuclear Information System (INIS)

Holmen, Johan G.; Outters, Nils

2002-05-01

The study concerns a mathematical modelling of a fractured rock mass and its investigations by use of theoretical boreholes and rock surfaces, with the purpose of analysing the efficiency (precision) of such investigations and determine the amount of investigations necessary to obtain reliable estimations of the structural-geological parameters of the studied rock mass. The study is not about estimating suitable sample sizes to be used in site investigations.The purpose of the study is to analyse the amount of information necessary for deriving estimates of the geological parameters studied, within defined confidence intervals and confidence level In other words, how the confidence in models of the rock mass (considering a selected number of parameters) will change with amount of information collected form boreholes and surfaces. The study is limited to a selected number of geometrical structural-geological parameters: Fracture orientation: mean direction and dispersion (Fisher Kappa and SRI). Different measures of fracture density (P10, P21 and P32). Fracture trace-length and strike distributions as seen on horizontal windows. A numerical Discrete Fracture Network (DFN) was used for representation of a fractured rock mass. The DFN-model was primarily based on the properties of an actual fracture network investigated at the Aespoe Hard Rock Laboratory. The rock mass studied (DFN-model) contained three different fracture sets with different orientations and fracture densities. The rock unit studied was statistically homogeneous. The study includes a limited sensitivity analysis of the properties of the DFN-model. The study is a theoretical and computer-based comparison between samples of fracture properties of a theoretical rock unit and the known true properties of the same unit. The samples are derived from numerically generated boreholes and surfaces that intersect the DFN-network. Two different boreholes are analysed; a vertical borehole and a borehole that is

Preparation of theoretical scanning tunneling microscope images of adsorbed molecules: a theoretical study of benzene on the Cu(110) surface

International Nuclear Information System (INIS)

Shapter, J.G.; Rogers, B.L.; Ford, M.J.

2003-01-01

Full text: Since its development in 1982, the Scanning Tunneling Microscope (STM) has developed into a powerful tool for the study of surfaces and adsorbates. However, the utility of the technique can be further enhanced through the development of techniques for generating theoretical STM images. This is particularly true when studying molecules adsorbed on a substrate, as the results are often interpreted superficially due to an inadequate understanding of the orbital overlap probed in the experiment. A method of preparing theoretical scanning tunneling microscope (STM) images using comparatively inexpensive desktop computers and the commercially available CRYSTAL98 package is presented through a study of benzene adsorbed on the Cu(110) surface. Density Functional Theory (DFT) and Hartree-Fock (HF) methods are used to model clean Cu(110) slabs of various thicknesses and to simulate the adsorption of benzene onto these slabs. Eight possible orientations of benzene on the Cu(110) surface are proposed, and the optimum orientation according to the calculations is presented. Theoretical STM images of the Cu(110) surface and benzene adsorbed on the Cu(110) surface are compared with experimental STM images of the system from a published study. Significant differences are observed and are examined in detail

The low energy frontier: searches for ultra-light particles beyond the Standard Model

CERN Multimedia

CERN. Geneva

2012-01-01

In the recent years theoretical studies and astrophysical observations have confirmed that unknown constituents of our universe like dark matter may find its explanation not only at large-scale experiments at highest energies, but could also show up at the opposite energy scale. In many laboratories world-wide searches for axions, axion-like particles, hidden photons, chameleons or other so-called WISPs with masses below the eV scale are ongoing. Examples at DESY are the experiments ALPS ("Any Light Particle Search") and SHIPS ("Solar HIdden Photon Search"). At CERN CAST and OSQAR take data. In all these experiments new particles could manifest themselves in a very spectacular manner. Light would apparently shine through thickest walls. The results of a first generation of laboratory and astrophysics experiments will be summarized and plans for future enterprises be discussed

Advanced language modeling approaches, case study: Expert search

NARCIS (Netherlands)

Hiemstra, Djoerd

2008-01-01

This tutorial gives a clear and detailed overview of advanced language modeling approaches and tools, including the use of document priors, translation models, relevance models, parsimonious models and expectation maximization training. Expert search will be used as a case study to explain the

Is there a time trend in medical practice variations?: a review of the literature and an critical analysis of theoretical approaches.

NARCIS (Netherlands)

Groenewegen, P.P.; Westert, G.P.

2004-01-01

The aim of this study was to review the research evidence for a decreasing time trend in medical practice variation and to contribute to our theoretical understanding of trends in medical practice variations. We searched Pubmed for articles reporting on time trends in medical practice variations.

Theoretical studies on aerosol agglomeration processes

Energy Technology Data Exchange (ETDEWEB)

Lehtinen, K.E.J. [VTT Energy, Espoo (Finland). Energy Use

1997-12-31

In this thesis, theoretical modeling of certain aerosol systems has been presented. At first, the aerosol general dynamic equation is introduced, along with a discretization routine for its numerical solution. Of the various possible phenomena affecting aerosol behaviour, this work is mostly focused on aerosol agglomeration. The fundamentals of aerosol agglomeration theory are thus briefly reviewed. The two practical applications of agglomeration studied in this thesis are flue gas cleaning using an electrical agglomerator and nanomaterial synthesis with a free jet reactor. In an electrical agglomerator the aerosol particles are charged and brought into an alternating electric field. The aim is to remove submicron particles from flue gases by collisions with larger particles before conventional gas cleaning devices that have a clear penetration window in the problematic 0.1-1{mu}m size range. A mathematical model was constructed to find out the effects of the different system parameters on the agglomerator`s performance. A crucial part of this task was finding out the collision efficiencies of particles of varying size and charge. The original idea was to use unipolar charging of the particles, and a laboratory scale apparatus was constructed for this purpose. Both theory and experiments clearly show that significant removal of submicron particles can not be achieved by such an arrangement. The theoretical analysis further shows that if the submicron particles and the large collector particles were charged with opposite polarity, significant removal of the submicron particles could be obtained. The second application of agglomeration considered in this thesis is predicting/controlling nanoparticle size in the gas-to-particle aerosol route to material synthesis. In a typical material reactor, a precursor vapor reacts to form molecules of the desired material. In a cooling environment, a particulate phase forms, the dynamics of which are determined by the rates of

Theoretical studies on aerosol agglomeration processes

Energy Technology Data Exchange (ETDEWEB)

Lehtinen, K E.J. [VTT Energy, Espoo (Finland). Energy Use

1998-12-31

In this thesis, theoretical modeling of certain aerosol systems has been presented. At first, the aerosol general dynamic equation is introduced, along with a discretization routine for its numerical solution. Of the various possible phenomena affecting aerosol behaviour, this work is mostly focused on aerosol agglomeration. The fundamentals of aerosol agglomeration theory are thus briefly reviewed. The two practical applications of agglomeration studied in this thesis are flue gas cleaning using an electrical agglomerator and nanomaterial synthesis with a free jet reactor. In an electrical agglomerator the aerosol particles are charged and brought into an alternating electric field. The aim is to remove submicron particles from flue gases by collisions with larger particles before conventional gas cleaning devices that have a clear penetration window in the problematic 0.1-1{mu}m size range. A mathematical model was constructed to find out the effects of the different system parameters on the agglomerator`s performance. A crucial part of this task was finding out the collision efficiencies of particles of varying size and charge. The original idea was to use unipolar charging of the particles, and a laboratory scale apparatus was constructed for this purpose. Both theory and experiments clearly show that significant removal of submicron particles can not be achieved by such an arrangement. The theoretical analysis further shows that if the submicron particles and the large collector particles were charged with opposite polarity, significant removal of the submicron particles could be obtained. The second application of agglomeration considered in this thesis is predicting/controlling nanoparticle size in the gas-to-particle aerosol route to material synthesis. In a typical material reactor, a precursor vapor reacts to form molecules of the desired material. In a cooling environment, a particulate phase forms, the dynamics of which are determined by the rates of

Theoretical framework to study exercise motivation for breast cancer risk reduction.

Science.gov (United States)

Wood, Maureen E

2008-01-01

To identify an appropriate theoretical framework to study exercise motivation for breast cancer risk reduction among high-risk women. An extensive review of the literature was conducted to gather relevant information pertaining to the Health Promotion Model, self-determination theory, social cognitive theory, Health Belief Model, Transtheoretical Model, theory of planned behavior, and protection motivation theory. An iterative approach was used to summarize the literature related to exercise motivation within each theoretical framework. Protection motivation theory could be used to examine the effects of perceived risk and self-efficacy in motivating women to exercise to facilitate health-related behavioral change. Evidence-based research within a chosen theoretical model can aid practitioners when making practical recommendations to reduce breast cancer risk.

CO oxidation on gold nanoparticles: Theoretical studies

DEFF Research Database (Denmark)

Remediakis, Ioannis; Lopez, Nuria; Nørskov, Jens Kehlet

2005-01-01

We present a summary of our theoretical results regarding CO oxidation on both oxide-supported and isolated gold nanoparticles. Using Density Functional Theory we have studied the adsorption of molecules and the oxidation reaction of CO on gold clusters. Low-coordinated sites on the gold...... nanoparticles can adsorb small inorganic molecules such as O2 and CO, and the presence of these sites is the key factor for the catalytic properties of supported gold nanoclusters. Other contributions, induced by the presence of the support, can provide parallel channels for the reaction and modulate the final...

Search for the Pentaquark via the Decay $P^0_{\\bar{c} s} \\to K^{*} K p$

Energy Technology Data Exchange (ETDEWEB)

Hurvits, Gilhad [Tel Aviv U.

1997-12-01

The goal of this work was to search for the pentaquark state via the $K^* Kp$ decay channel, within the framework of E791. The thesis covered the theoretical motivation that led to the search, description of the experimental setup, the analysis methods and the results

The Study of Environment on Aboriginal Resilience and Child Health (SEARCH: study protocol

Directory of Open Access Journals (Sweden)

2010-05-01

Full Text Available Abstract Background Aboriginal Australians have a life expectancy more than ten years less than that of non-Aboriginal Australians, reflecting their disproportionate burden of both communicable and non-communicable disease throughout the lifespan. Little is known about the health and health trajectories of Aboriginal children and, although the majority of Aboriginal people live in urban areas, data are particularly sparse in relation to children living in urban areas. Methods/Design The Study of Environment on Aboriginal Resilience and Child Health (SEARCH is a cohort study of Aboriginal children aged 0-17 years, from urban and large regional centers in New South Wales, Australia. SEARCH focuses on Aboriginal community identified health priorities of: injury; otitis media; vaccine-preventable conditions; mental health problems; developmental delay; obesity; and risk factors for chronic disease. Parents/caregivers and their children are invited to participate in SEARCH at the time of presentation to one of the four participating Aboriginal Community Controlled Health Organisations at Mount Druitt, Campbelltown, Wagga Wagga and Newcastle. Questionnaire data are obtained from parents/caregivers and children, along with signed permission for follow-up through repeat data collection and data linkage. All children have their height, weight, waist circumference and blood pressure measured and complete audiometry, otoscopy/pneumatic otoscopy and tympanometry. Children aged 1-7 years have speech and language assessed and their parents/caregivers complete the Parental Evaluation of Developmental Status. The Study aims to recruit 1700 children by the end of 2010 and to secure resources for long term follow up. From November 2008 to March 2010, 1010 children had joined the study. From those 446 children with complete data entry, participating children ranged in age from 2 weeks to 17 years old, with 144 aged 0-3, 147 aged 4-7, 75 aged 8-10 and 79 aged 11

A theoretical study of absorption equilibria in silicon CVD

NARCIS (Netherlands)

Gardeniers, Johannes G.E.; Giling, L.J.; de Jong, F.; van der Eerden, J.P.

1990-01-01

As part of a theoretical study of adsorption processes in the chemical vapour deposition of silicon, thermochemical data are derived for the adsorption of Si-H species on the Si(111) and the dimer-reconstructed Si(001)-(2 x 1) surfaces. Essential contributions to the heats of adsorption appear to be

PubMed search strings for the study of agricultural workers' diseases.

Science.gov (United States)

Mattioli, Stefano; Gori, Davide; Di Gregori, Valentina; Ricotta, Lara; Baldasseroni, Alberto; Farioli, Andrea; Zanardi, Francesca; Galletti, Stefania; Colosio, Claudio; Curti, Stefania; Violante, Francesco S

2013-12-01

Several optimized search strategies have been developed in Medicine, and more recently in Occupational Medicine. The aim of this study was to identify efficient PubMed search strategies to retrieve articles regarding putative occupational determinants of agricultural workers' diseases. We selected the Medical Subjects Heading (MeSH) term agricultural workers' diseases and six MeSH terms describing farm work (agriculture, agrochemicals NOT pesticides, animal husbandry, pesticides, rural health, rural population) alongside 61 other promising terms. We estimated proportions of articles containing potentially pertinent information regarding occupational etiology to formulate two search strategies (one "more specific," one "more sensitive"). We applied these strategies to retrieve information on the possible occupational etiology among agricultural workers of kidney cancer, knee osteoarthritis, and multiple sclerosis. We evaluated the number of needed to read (NNR) abstracts to identify one potentially pertinent article in the context of these pathologies. The "more specific" search string was based on the combination of terms that yielded the highest proportion (40%) of potentially pertinent abstracts. The "more sensitive" string was based on use of broader search fields and additional coverage provided by other search terms under study. Using the "more specific" string, the NNR to find one potentially pertinent article were: 1.1 for kidney cancer; 1.4 for knee osteoarthritis; 1.2 for multiple sclerosis. Using the sensitive strategy, the NNR were 1.4, 3.6, and 6.3, respectively. The proposed strings could help health care professionals explore putative occupational etiology for agricultural workers' diseases (even if not generally thought to be work related). © 2013 Wiley Periodicals, Inc.

Methodological developments in searching for studies for systematic reviews: past, present and future?

Science.gov (United States)

Lefebvre, Carol; Glanville, Julie; Wieland, L Susan; Coles, Bernadette; Weightman, Alison L

2013-09-25

The Cochrane Collaboration was established in 1993, following the opening of the UK Cochrane Centre in 1992, at a time when searching for studies for inclusion in systematic reviews was not well-developed. Review authors largely conducted their own searches or depended on medical librarians, who often possessed limited awareness and experience of systematic reviews. Guidance on the conduct and reporting of searches was limited. When work began to identify reports of randomized controlled trials (RCTs) for inclusion in Cochrane Reviews in 1992, there were only approximately 20,000 reports indexed as RCTs in MEDLINE and none indexed as RCTs in Embase. No search filters had been developed with the aim of identifying all RCTs in MEDLINE or other major databases. This presented The Cochrane Collaboration with a considerable challenge in identifying relevant studies.Over time, the number of studies indexed as RCTs in the major databases has grown considerably and the Cochrane Central Register of Controlled Trials (CENTRAL) has become the best single source of published controlled trials, with approximately 700,000 records, including records identified by the Collaboration from Embase and MEDLINE. Search filters for various study types, including systematic reviews and the Cochrane Highly Sensitive Search Strategies for RCTs, have been developed. There have been considerable advances in the evidence base for methodological aspects of information retrieval. The Cochrane Handbook for Systematic Reviews of Interventions now provides detailed guidance on the conduct and reporting of searches. Initiatives across The Cochrane Collaboration to improve the quality inter alia of information retrieval include: the recently introduced Methodological Expectations for Cochrane Intervention Reviews (MECIR) programme, which stipulates 'mandatory' and 'highly desirable' standards for various aspects of review conduct and reporting including searching, the development of Standard Training

Search for Dark Matter in the mono-X final states (X = jets, Z, W, H) with ATLAS

CERN Document Server

Lo Sterzo, Francesco; The ATLAS collaboration

2018-01-01

Dark Matter searches in the ATLAS Experiment are perfomed analysing a wide number of experimental signatures. Among these, mono-X searches are a powerful tool since many models can be probed depending on the nature (jet, photon, vector boson, Higgs boson) of the Standard Model object which is used to identify and select the events. In this report a short introduction of the theoretical framweork is given, followed by three examples of different signatures that probe different theoretical models that describe an interaction between the Standard Model and Dark Matter.

A theoretical and spectroscopic study of co-amorphous naproxen and indomethacin

DEFF Research Database (Denmark)

Löbmann, Korbinian; Laitinen, Riikka; Grohganz, Holger

2013-01-01

. In this study, the co-amorphous drug mixture containing naproxen (NAP) and indomethacin (IND) was investigated using infrared spectroscopy (IR) and quantum mechanical calculations. The structures of both drugs were optimized as monomer, homodimer and heterodimer using density functional theory and used...... for the calculation of IR spectra. Conformational analysis confirmed that the optimized structures were suitable for the theoretical prediction of the spectra. Vibrational modes from the calculation could be matched with experimentally observed spectra for crystalline and amorphous NAP and IND, and it could be shown...... that both drugs exist as homodimers in their respective individual amorphous form. With the results from the experimental single amorphous drugs and theoretical homodimers, a detailed analysis of the experimental co-amorphous and theoretical heterodimer spectra was performed and evaluated. It is suggested...

Utilizing mixed methods research in analyzing Iranian researchers’ informarion search behaviour in the Web and presenting current pattern

Directory of Open Access Journals (Sweden)

Maryam Asadi

2015-12-01

, information evaluation, information selection, information management, and stop/ continue.These stages located in greater four categories: search initiation behaviors, formulating search queries, search navigational behaviors, and information processing behaviors.The study contributes to the theoretical basis of Web search research. It also raises various questions within the context of user studies.

Search for the critical point of strongly interacting matter at the CERN SPS NA61/SHINE experiment

CERN Document Server

Turko, L

2015-01-01

The NA61/SHINE experiment performs a detailed study of the onset of deconfinement and search for critical point of hadronic matter by colliding nuclei of different sizes at various beam momenta from 13A to 158A GeV/c. Experimental setup and results on the theoretically expected signatures are discussed.

Searching for information on the World Wide Web with a search engine: a pilot study on cognitive flexibility in younger and older users.

Science.gov (United States)

Dommes, Aurelie; Chevalier, Aline; Rossetti, Marilyne

2010-04-01

This pilot study investigated the age-related differences in searching for information on the World Wide Web with a search engine. 11 older adults (6 men, 5 women; M age=59 yr., SD=2.76, range=55-65 yr.) and 12 younger adults (2 men, 10 women; M=23.7 yr., SD=1.07, range=22-25 yr.) had to conduct six searches differing in complexity, and for which a search method was or was not induced. The results showed that the younger and older participants provided with an induced search method were less flexible than the others and produced fewer new keywords. Moreover, older participants took longer than the younger adults, especially in the complex searches. The younger participants were flexible in the first request and spontaneously produced new keywords (spontaneous flexibility), whereas the older participants only produced new keywords when confronted by impasses (reactive flexibility). Aging may influence web searches, especially the nature of keywords used.

Samaru Journal of Information Studies: Advanced Search

African Journals Online (AJOL)

Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

Ghana Journal of Development Studies: Advanced Search

African Journals Online (AJOL)

Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

Tanzania Journal of Development Studies: Advanced Search

African Journals Online (AJOL)

Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

Review of Southern African Studies: Advanced Search

African Journals Online (AJOL)

Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

Spin-dependent Hall effect in degenerate semiconductors: a theoretical study

Energy Technology Data Exchange (ETDEWEB)

Idrish Miah, M [Nanoscale Science and Technology Centre, Griffith University, Nathan, Brisbane, QLD 4111 (Australia)], E-mail: m.miah@griffith.edu.au

2008-10-15

The spin-dependent Hall (SDH) effect in degenerate semiconductors is investigated theoretically. Starting from a two-component drift-diffusion equation, an expression for SDH voltage (V{sub SDH}) is derived, and drift and diffusive contributions to V{sub SDH} are studied. For the possible enhancement of the diffusive part, degenerate and nondegenerate cases are examined. We find that due to an increase in the diffusion coefficient V{sub SDH} increases in a degenerate semiconductor, consistent with the experimental observations. The expression for V{sub SDH} is reduced in three limiting cases, namely diffusive, drift-diffusion crossover and drift, and is analysed. The results agree with those obtained in recent theoretical investigations.

Spin-dependent Hall effect in degenerate semiconductors: a theoretical study

International Nuclear Information System (INIS)

Idrish Miah, M

2008-01-01

The spin-dependent Hall (SDH) effect in degenerate semiconductors is investigated theoretically. Starting from a two-component drift-diffusion equation, an expression for SDH voltage (V SDH ) is derived, and drift and diffusive contributions to V SDH are studied. For the possible enhancement of the diffusive part, degenerate and nondegenerate cases are examined. We find that due to an increase in the diffusion coefficient V SDH increases in a degenerate semiconductor, consistent with the experimental observations. The expression for V SDH is reduced in three limiting cases, namely diffusive, drift-diffusion crossover and drift, and is analysed. The results agree with those obtained in recent theoretical investigations.

Search route decision of environmental monitoring at emergency time

International Nuclear Information System (INIS)

Aoyama, Isao

1979-01-01

The search route decision method is reviewed, especially the adequate arrangement of monitors in view of time in the information-gathering activity by transferring the monitors on the horizontal space after the confirmation of the abnormal release of radioactive material. As for the field of the theory of search, the developmental history is explained, namely the experiences of the naval anti submarine operation in WW-2, the salvage activities and the search problem on the sea. The kinematics for search, the probability theory for detection and the optimum distribution for search are the most important contents of the application of theory of search relating to the environmental monitoring at emergency condition. The combination of a search model consists of the peculiarity of targets, the peculiarity of observers and the standard of optimality. The peculiarity of targets is divided into the space of search, the number of targets, the way of appearance of targets and the motion of targets. The peculiarity of observers is divided into the number of observers, the divisibility of efforts for search, the credibility of search information and the search process. The standard of optimality is divided into the maximum probability of detection, the minimum risk expected and the others. Each item written above of search model is explained. Concerning the formulation of the search model, the theoretical equations for detection probability, discovery potential and instantaneous detection probability, density are derived, and these equations are evaluated and explained. The future plan is to advance the search technology so as to evaluate the detection potential to decide the route of running a monitoring car for a nuclear power plant at accidental condition. (Nakai, Y.)

Noise propagation in iterative reconstruction algorithms with line searches

International Nuclear Information System (INIS)

Qi, Jinyi

2003-01-01

In this paper we analyze the propagation of noise in iterative image reconstruction algorithms. We derive theoretical expressions for the general form of preconditioned gradient algorithms with line searches. The results are applicable to a wide range of iterative reconstruction problems, such as emission tomography, transmission tomography, and image restoration. A unique contribution of this paper comparing to our previous work [1] is that the line search is explicitly modeled and we do not use the approximation that the gradient of the objective function is zero. As a result, the error in the estimate of noise at early iterations is significantly reduced

Theoretical & Experimental Research in Weak, Electromagnetic & Strong Interactions

Energy Technology Data Exchange (ETDEWEB)

Nandi, Satyanarayan [Oklahoma State Univ., Stillwater, OK (United States); Babu, Kaladi [Oklahoma State Univ., Stillwater, OK (United States); Rizatdinova, Flera [Oklahoma State Univ., Stillwater, OK (United States); Khanov, Alexander [Oklahoma State Univ., Stillwater, OK (United States); Haley, Joseph [Oklahoma State Univ., Stillwater, OK (United States)

2015-09-17

The conducted research spans a wide range of topics in the theoretical, experimental and phenomenological aspects of elementary particle interactions. Theory projects involve topics in both the energy frontier and the intensity frontier. The experimental research involves energy frontier with the ATLAS Collaboration at the Large Hadron Collider (LHC). In theoretical research, novel ideas going beyond the Standard Model with strong theoretical motivations were proposed, and their experimental tests at the LHC and forthcoming neutrino facilities were outlined. These efforts fall into the following broad categories: (i) TeV scale new physics models for LHC Run 2, including left-right symmetry and trinification symmetry, (ii) unification of elementary particles and forces, including the unification of gauge and Yukawa interactions, (iii) supersummetry and mechanisms of supersymmetry breaking, (iv) superworld without supersymmetry, (v) general models of extra dimensions, (vi) comparing signals of extra dimensions with those of supersymmetry, (vii) models with mirror quarks and mirror leptons at the TeV scale, (viii) models with singlet quarks and singlet Higgs and their implications for Higgs physics at the LHC, (ix) new models for the dark matter of the universe, (x) lepton flavor violation in Higgs decays, (xi) leptogenesis in radiative models of neutrino masses, (xii) light mediator models of non-standard neutrino interactions, (xiii) anomalous muon decay and short baseline neutrino anomalies, (xiv) baryogenesis linked to nucleon decay, and (xv) a new model for recently observed diboson resonance at the LHC and its other phenomenological implications. The experimental High Energy Physics group has been, and continues to be, a successful and productive contributor to the ATLAS experiment at the LHC. Members of the group performed search for gluinos decaying to stop and top quarks, new heavy gauge bosons decaying to top and bottom quarks, and vector-like quarks

Theoretical Studies Of Nucleation Kinetics And Nanodroplet Microstructure

International Nuclear Information System (INIS)

Wilemski, Gerald

2009-01-01

The goals of this project were to (1) explore ways of bridging the gap between fundamental molecular nucleation theories and phenomenological approaches based on thermodynamic reasoning, (2) test and improve binary nucleation theory, and (3) provide the theoretical underpinning for a powerful new experimental technique, small angle neutron scattering (SANS) from nanodroplet aerosols, that can probe the compositional structure of nanodroplets. This report summarizes the accomplishments of this project in realizing these goals. Publications supported by this project fall into three general categories: (1) theoretical work on nucleation theory (2) experiments and modeling of nucleation and condensation in supersonic nozzles, and (3) experimental and theoretical work on nanodroplet structure and neutron scattering. These publications are listed and briefly summarized in this report.

Experimental and theoretical studies of bombardment induced surface morphology changes

International Nuclear Information System (INIS)

Carter, G.; Nobes, M.J.; Williams, J.S.

1980-01-01

In this review results of experimental and theoretical studies of solid surface morphology changes due to ion bombardment are discussed. An attempt is undertaken to classify the observed specific features of a structure, generated by ion bombardment [ru

Theoretical Physics Division

International Nuclear Information System (INIS)

This report is a survey of the studies done in the Theoretical Physics Division of the Nuclear Physics Institute; the subjects studied in theoretical nuclear physics were the few-nucleon problem, nuclear structure, nuclear reactions, weak interactions, intermediate energy and high energy physics. In this last field, the subjects studied were field theory, group theory, symmetry and strong interactions [fr

Development of a theoretical framework of factors affecting patient safety incident reporting: a theoretical review of the literature

Science.gov (United States)

Hull, Louise; Soukup, Tayana; Mayer, Erik; Athanasiou, Thanos; Sevdalis, Nick; Darzi, Ara

2017-01-01

Objectives The development and implementation of incident reporting systems within healthcare continues to be a fundamental strategy to reduce preventable patient harm and improve the quality and safety of healthcare. We sought to identify factors contributing to patient safety incident reporting. Design To facilitate improvements in incident reporting, a theoretical framework, encompassing factors that act as barriers and enablers ofreporting, was developed. Embase, Ovid MEDLINE(R) and PsycINFO were searched to identify relevant articles published between January 1980 and May 2014. A comprehensive search strategy including MeSH terms and keywords was developed to identify relevant articles. Data were extracted by three independent researchers; to ensure the accuracy of data extraction, all studies eligible for inclusion were rescreened by two reviewers. Results The literature search identified 3049 potentially eligible articles; of these, 110 articles, including >29 726 participants, met the inclusion criteria. In total, 748 barriers were identified (frequency count) across the 110 articles. In comparison, 372 facilitators to incident reporting and 118 negative cases were identified. The top two barriers cited were fear of adverse consequences (161, representing 21.52% of barriers) and process and systems of reporting (110, representing 14.71% of barriers). In comparison, the top two facilitators were organisational (97, representing 26.08% of facilitators) and process and systems of reporting (75, representing 20.16% of facilitators). Conclusion A wide range of factors contributing to engagement in incident reporting exist. Efforts that address the current tendency to under-report must consider the full range of factors in order to develop interventions as well as a strategic policy approach for improvement. PMID:29284714

Experimental and theoretical study of magnetohydrodynamic ship models.

Science.gov (United States)

Cébron, David; Viroulet, Sylvain; Vidal, Jérémie; Masson, Jean-Paul; Viroulet, Philippe

2017-01-01

Magnetohydrodynamic (MHD) ships represent a clear demonstration of the Lorentz force in fluids, which explains the number of students practicals or exercises described on the web. However, the related literature is rather specific and no complete comparison between theory and typical small scale experiments is currently available. This work provides, in a self-consistent framework, a detailed presentation of the relevant theoretical equations for small MHD ships and experimental measurements for future benchmarks. Theoretical results of the literature are adapted to these simple battery/magnets powered ships moving on salt water. Comparison between theory and experiments are performed to validate each theoretical step such as the Tafel and the Kohlrausch laws, or the predicted ship speed. A successful agreement is obtained without any adjustable parameter. Finally, based on these results, an optimal design is then deduced from the theory. Therefore this work provides a solid theoretical and experimental ground for small scale MHD ships, by presenting in detail several approximations and how they affect the boat efficiency. Moreover, the theory is general enough to be adapted to other contexts, such as large scale ships or industrial flow measurement techniques.

Experimental and theoretical study of magnetohydrodynamic ship models.

Directory of Open Access Journals (Sweden)

David Cébron

Full Text Available Magnetohydrodynamic (MHD ships represent a clear demonstration of the Lorentz force in fluids, which explains the number of students practicals or exercises described on the web. However, the related literature is rather specific and no complete comparison between theory and typical small scale experiments is currently available. This work provides, in a self-consistent framework, a detailed presentation of the relevant theoretical equations for small MHD ships and experimental measurements for future benchmarks. Theoretical results of the literature are adapted to these simple battery/magnets powered ships moving on salt water. Comparison between theory and experiments are performed to validate each theoretical step such as the Tafel and the Kohlrausch laws, or the predicted ship speed. A successful agreement is obtained without any adjustable parameter. Finally, based on these results, an optimal design is then deduced from the theory. Therefore this work provides a solid theoretical and experimental ground for small scale MHD ships, by presenting in detail several approximations and how they affect the boat efficiency. Moreover, the theory is general enough to be adapted to other contexts, such as large scale ships or industrial flow measurement techniques.

Exploring the Relevance of Search Engines: An Overview of Google as a Case Study

Directory of Open Access Journals (Sweden)

Ricardo Beltrán-Alfonso

2017-08-01

Full Text Available The huge amount of data on the Internet and the diverse list of strategies used to try to link this information with relevant searches through Linked Data have generated a revolution in data treatment and its representation. Nevertheless, the conventional search engines like Google are kept as strategies with good reception to do search processes. The following article presents a study of the development and evolution of search engines, more specifically, to analyze the relevance of findings based on the number of results displayed in paging systems with Google as a case study. Finally, it is intended to contribute to indexing criteria in search results, based on an approach to Semantic Web as a stage in the evolution of the Web.

Nearest Neighbor Search in the Metric Space of a Complex Network for Community Detection

Directory of Open Access Journals (Sweden)

Suman Saha

2016-03-01

Full Text Available The objective of this article is to bridge the gap between two important research directions: (1 nearest neighbor search, which is a fundamental computational tool for large data analysis; and (2 complex network analysis, which deals with large real graphs but is generally studied via graph theoretic analysis or spectral analysis. In this article, we have studied the nearest neighbor search problem in a complex network by the development of a suitable notion of nearness. The computation of efficient nearest neighbor search among the nodes of a complex network using the metric tree and locality sensitive hashing (LSH are also studied and experimented. For evaluation of the proposed nearest neighbor search in a complex network, we applied it to a network community detection problem. Experiments are performed to verify the usefulness of nearness measures for the complex networks, the role of metric tree and LSH to compute fast and approximate node nearness and the the efficiency of community detection using nearest neighbor search. We observed that nearest neighbor between network nodes is a very efficient tool to explore better the community structure of the real networks. Several efficient approximation schemes are very useful for large networks, which hardly made any degradation of results, whereas they save lot of computational times, and nearest neighbor based community detection approach is very competitive in terms of efficiency and time.

Theoretical model simulations for the global Thermospheric Mapping Study (TMS) periods

Science.gov (United States)

Rees, D.; Fuller-Rowell, T. J.

Theoretical and semiempirical models of the solar UV/EUV and of the geomagnetic driving forces affecting the terrestrial mesosphere and thermosphere have been used to generate a series of representative numerical time-dependent and global models of the thermosphere, for the range of solar and geoamgnetic activity levels which occurred during the three Thermospheric Mapping Study periods. The simulations obtained from these numerical models are compared with observations, and with the results of semiempirical models of the thermosphere. The theoretical models provide a record of the magnitude of the major driving forces which affected the thermosphere during the study periods, and a baseline against which the actual observed structure and dynamics can be compared.

Sorting, Searching, and Simulation in the MapReduce Framework

DEFF Research Database (Denmark)

Goodrich, Michael T.; Sitchinava, Nodari; Zhang, Qin

2011-01-01

usefulness of our approach by designing and analyzing efficient MapReduce algorithms for fundamental sorting, searching, and simulation problems. This study is motivated by a goal of ultimately putting the MapReduce framework on an equal theoretical footing with the well-known PRAM and BSP parallel...... in parallel computational geometry for the MapReduce framework, which result in efficient MapReduce algorithms for sorting, 2- and 3-dimensional convex hulls, and fixed-dimensional linear programming. For the case when mappers and reducers have a memory/message-I/O size of M = (N), for a small constant > 0...

Eysenbach, Tuische and Diepgen’s Evaluation of Web Searching for Identifying Unpublished Studies for Systematic Reviews: An Innovative Study Which is Still Relevant Today.

Directory of Open Access Journals (Sweden)

Simon Briscoe

2016-09-01

Full Text Available A Review of: Eysenbach, G., Tuische, J. & Diepgen, T.L. (2001. Evaluation of the usefulness of Internet searches to identify unpublished clinical trials for systematic reviews. Medical Informatics and the Internet in Medicine, 26(3, 203-218. http://dx.doi.org/10.1080/14639230110075459 Objective – To consider whether web searching is a useful method for identifying unpublished studies for inclusion in systematic reviews. Design – Retrospective web searches using the AltaVista search engine were conducted to identify unpublished studies – specifically, clinical trials – for systematic reviews which did not use a web search engine. Setting – The Department of Clinical Social Medicine, University of Heidelberg, Germany. Subjects – n/a Methods – Pilot testing of 11 web search engines was carried out to determine which could handle complex search queries. Pre-specified search requirements included the ability to handle Boolean and proximity operators, and truncation searching. A total of seven Cochrane systematic reviews were randomly selected from the Cochrane Library Issue 2, 1998, and their bibliographic database search strategies were adapted for the web search engine, AltaVista. Each adaptation combined search terms for the intervention, problem, and study type in the systematic review. Hints to planned, ongoing, or unpublished studies retrieved by the search engine, which were not cited in the systematic reviews, were followed up by visiting websites and contacting authors for further details when required. The authors of the systematic reviews were then contacted and asked to comment on the potential relevance of the identified studies. Main Results – Hints to 14 unpublished and potentially relevant studies, corresponding to 4 of the 7 randomly selected Cochrane systematic reviews, were identified. Out of the 14 studies, 2 were considered irrelevant to the corresponding systematic review by the systematic review authors. The

Dyniqx: a novel meta-search engine for metadata based cross search

OpenAIRE

Zhu, Jianhan; Song, Dawei; Eisenstadt, Marc; Barladeanu, Cristi; Rüger, Stefan

2008-01-01

The effect of metadata in collection fusion has not been sufficiently studied. In response to this, we present a novel meta-search engine called Dyniqx for metadata based cross search. Dyniqx exploits the availability of metadata in academic search services such as PubMed and Google Scholar etc for fusing search results from heterogeneous search engines. In addition, metadata from these search engines are used for generating dynamic query controls such as sliders and tick boxes etc which are ...

Non-commutative cryptography and complexity of group-theoretic problems

CERN Document Server

Myasnikov, Alexei; Ushakov, Alexander

2011-01-01

This book is about relations between three different areas of mathematics and theoretical computer science: combinatorial group theory, cryptography, and complexity theory. It explores how non-commutative (infinite) groups, which are typically studied in combinatorial group theory, can be used in public-key cryptography. It also shows that there is remarkable feedback from cryptography to combinatorial group theory because some of the problems motivated by cryptography appear to be new to group theory, and they open many interesting research avenues within group theory. In particular, a lot of emphasis in the book is put on studying search problems, as compared to decision problems traditionally studied in combinatorial group theory. Then, complexity theory, notably generic-case complexity of algorithms, is employed for cryptanalysis of various cryptographic protocols based on infinite groups, and the ideas and machinery from the theory of generic-case complexity are used to study asymptotically dominant prop...

Theoretical and experimental studies on electric field and confinement in helical systems

International Nuclear Information System (INIS)

Sanuki, H.; Itoh, K.; Todoroki, J.; Ida, K.; Idei, H.; Iguchi, H.; Yamada, H.

1994-06-01

The present study consists of two parts. The first part is oriented to a theoretical model of selfconsistent analysis to determine simultaneously the electric field and loss cone boundary in heliotron/torsatron configurations under the influence of nonclassical particle losses. The second part is referred to the analysis on NBI heated and ECH plasmas in Compact Helical System (CHS) device. A comparison is made between theoretical results and experimental observations. (author)

A Theoretic Basis for IS? The Contribution of ANT

Directory of Open Access Journals (Sweden)

Jim Underwood

2002-11-01

Full Text Available Representation is a key issue of IS design and operation that is often ignored. Actor-network theory (ANT, a semiotic theory of stakeholders, provides a way of dealing with representation. Combining aspects of ANT and Foucault's discourse theory allows us to include concepts as actors and promises a flexible and durable foundation for IS practice, but ANT itself indicates that the search for a purely theoretical foundation for IS is misguided.

Theoretical Studies of Nanoclusters (Briefing Charts)

Science.gov (United States)

2015-07-23

nanoclusters. However, scanning transmission electron microscopy ( STEM ) measures show cluster inversion occurred to produce MgyCux(!) a) copper atoms b...methane (née CLL -1) as a potential explosive ingredient: a theoretical study”, Propellants, Explosives, Pyrotechnics 38, 9-13 (2013). Jesus Paulo L

Experimental and theoretical high energy physics research

International Nuclear Information System (INIS)

1992-01-01

Progress in the various components of the UCLA High-Energy Physics Research program is summarized, including some representative figures and lists of resulting presentations and published papers. Principal efforts were directed at the following: (I) UCLA hadronization model, PEP4/9 e + e - analysis, bar P decay; (II) ICARUS and astroparticle physics (physics goals, technical progress on electronics, data acquisition, and detector performance, long baseline neutrino beam from CERN to the Gran Sasso and ICARUS, future ICARUS program, and WIMP experiment with xenon), B physics with hadron beams and colliders, high-energy collider physics, and the φ factory project; (III) theoretical high-energy physics; (IV) H dibaryon search, search for K L 0 → π 0 γγ and π 0 ν bar ν, and detector design and construction for the FNAL-KTeV project; (V) UCLA participation in the experiment CDF at Fermilab; and (VI) VLPC/scintillating fiber R ampersand D

An experimental and theoretical model of children’s search behavior in relation to target conspicuity and spatial distribution

Science.gov (United States)

Rosetti, Marcos Francisco; Pacheco-Cobos, Luis; Larralde, Hernán; Hudson, Robyn

2010-11-01

This work explores search trajectories of children attempting to find targets distributed on a playing field. This task, of ludic nature, was developed to test the effect of conspicuity and spatial distribution of targets on the searcher’s performance. The searcher’s path was recorded by a Global Positioning System (GPS) device attached to the child’s waist. Participants were not rewarded nor their performance rated. Variation in the conspicuity of the targets influenced search performance as expected; cryptic targets resulted in slower searches and longer, more tortuous paths. Extracting the main features of the paths showed that the children: (1) paid little attention to the spatial distribution and at least in the conspicuous condition approximately followed a nearest neighbor pattern of target collection, (2) were strongly influenced by the conspicuity of the targets. We implemented a simple statistical model for the search rules mimicking the children’s behavior at the level of individual (coarsened) steps. The model reproduced the main features of the children’s paths without the participation of memory or planning.

Theoretical and experimental study of modes associated to ion cyclotron heating on TFR

International Nuclear Information System (INIS)

Pignol, L.

1985-05-01

In this work, the ion cyclotron wave evolution is followed thanks to a coherent scattering device using carbon dioxide laser radiation. A theoretical part presents the dispersion equation that obey the waves excited in the plasma by antenna emitting ion cyclotron frequency. Then measurements given by the diagnostic are given. Fast and slow waves evidenced theoretically, are experimentally observed. Two simple theoretical models allow to extract physical quantities characteristics of the two modes. These two modes are followed along the radial coordinate of the tore and their behavior through the hybrid curve is studied. measured spectra shape is shown to confirm the described numerical code validity. Time study of the slow wave shows of internal relaxation phenomenon of plasma [fr

A theoretical and experimental study of microshield circuits

Science.gov (United States)

Dib, Nihad I.; Drayton, Rhonda F.; Katehi, Linda P. B.

1993-05-01

The novel type of monolithic planar transmission line presently studied theoretically and experimentally operates without via-holes or ground-equalizing air bridges; it also radiates less than conventional coplanar waveguides and furnishes a wide range of impedances in virtue of its many design parameters. The space-domain integral equation method is used to analyze several discontinuities of the proposed line. It is shown that the proposed line discontinuities radiate less than the corresponding coplanar waveguide cases.

Expected Fitness Gains of Randomized Search Heuristics for the Traveling Salesperson Problem.

Science.gov (United States)

Nallaperuma, Samadhi; Neumann, Frank; Sudholt, Dirk

2017-01-01

Randomized search heuristics are frequently applied to NP-hard combinatorial optimization problems. The runtime analysis of randomized search heuristics has contributed tremendously to our theoretical understanding. Recently, randomized search heuristics have been examined regarding their achievable progress within a fixed-time budget. We follow this approach and present a fixed-budget analysis for an NP-hard combinatorial optimization problem. We consider the well-known Traveling Salesperson Problem (TSP) and analyze the fitness increase that randomized search heuristics are able to achieve within a given fixed-time budget. In particular, we analyze Manhattan and Euclidean TSP instances and Randomized Local Search (RLS), (1+1) EA and (1+[Formula: see text]) EA algorithms for the TSP in a smoothed complexity setting, and derive the lower bounds of the expected fitness gain for a specified number of generations.

An Activity Theoretical Approach to Social Interaction during Study Abroad

Science.gov (United States)

Shively, Rachel L.

2016-01-01

This case study examines how one study abroad student oriented to social interaction during a semester in Spain. Using an activity theoretical approach, the findings indicate that the student not only viewed social interaction with his Spanish host family and an expert-Spanish-speaking age peer as an opportunity for second language (L2) learning,…

Assessment and Comparison of Search capabilities of Web-based Meta-Search Engines: A Checklist Approach

Directory of Open Access Journals (Sweden)

Alireza Isfandiyari Moghadam

2010-03-01

Full Text Available   The present investigation concerns evaluation, comparison and analysis of search options existing within web-based meta-search engines. 64 meta-search engines were identified. 19 meta-search engines that were free, accessible and compatible with the objectives of the present study were selected. An author’s constructed check list was used for data collection. Findings indicated that all meta-search engines studied used the AND operator, phrase search, number of results displayed setting, previous search query storage and help tutorials. Nevertheless, none of them demonstrated any search options for hypertext searching and displaying the size of the pages searched. 94.7% support features such as truncation, keywords in title and URL search and text summary display. The checklist used in the study could serve as a model for investigating search options in search engines, digital libraries and other internet search tools.

Theoretical study of catalytic hydrogenation of oxirane and its methyl ...

African Journals Online (AJOL)

C3H6O) is its methyl derivative. Theoretical studies on catalytic hydrogenation of both compounds, in presence of aluminium chloride (AlCl3) catalyst, are carried out. The products of reactions are ethanol and propan-1-ol from oxirane and ...

Search for new light bosons in high energy astronomy

International Nuclear Information System (INIS)

Wouters, Denis

2014-01-01

High-Energy astronomy studies the most violent phenomena in the universe with observations in a large spectrum of energies ranging from X rays to very high energy gamma rays (1 keV - 100 TeV). Such phenomena could be for instance supernovae explosions and their remnants, pulsars and pulsar wind nebulae or ultra relativistic jets formation by active galactic nuclei. Understanding these phenomena requires to use well-known particle physics processes. By means of high energy photons, studying such phenomena enables one to search for physics beyond the standard model. Concepts regarding the emission and propagation of high-energy photons are introduced and applied to study their emission by extragalactic sources and to constrain the extragalactic background light which affects their propagation. In this thesis, these high-energy extragalactic emitters are observed in order to search for new light bosons such as axion-like particles (ALPs). The theoretical framework of this family of hypothetical particles is reviewed as well as the associated phenomenology. In particular, because of their coupling to two photons, ALPs oscillate with photons in an external magnetic field. A new signature of such oscillations in turbulent magnetic fields, under the form of stochastic irregularities in the source energy spectrum, is introduced and discussed. A search for ALPs with the HESS telescopes with this new signature is presented, resulting in the first constraints on ALPs parameters coming from high-energy astronomy. Current constraints on ALPs at very low masses are improved by searching for the same signature in X-ray observations. An extension of these constraints to scalar field models for modified gravity in the framework of dark energy is then discussed. The potential of the search for ALPs with CTA, the prospected gamma-ray astronomy instrument, is eventually studied; in particular, a new observable is proposed that relies on the high number of sources that are expected to

Search for new physics at a super-B factory

Indian Academy of Sciences (India)

The importance of a super- factory in the search for new physics, in particular, due to CP-odd phase(s) from physics beyond the standard model is surveyed. The first point to emphasize is that we now know how to directly measure all three angles of the unitarity triangle very cleanly, i.e. without theoretical assumptions with ...

Estimating search engine index size variability: a 9-year longitudinal study.

Science.gov (United States)

van den Bosch, Antal; Bogers, Toine; de Kunder, Maurice

One of the determining factors of the quality of Web search engines is the size of their index. In addition to its influence on search result quality, the size of the indexed Web can also tell us something about which parts of the WWW are directly accessible to the everyday user. We propose a novel method of estimating the size of a Web search engine's index by extrapolating from document frequencies of words observed in a large static corpus of Web pages. In addition, we provide a unique longitudinal perspective on the size of Google and Bing's indices over a nine-year period, from March 2006 until January 2015. We find that index size estimates of these two search engines tend to vary dramatically over time, with Google generally possessing a larger index than Bing. This result raises doubts about the reliability of previous one-off estimates of the size of the indexed Web. We find that much, if not all of this variability can be explained by changes in the indexing and ranking infrastructure of Google and Bing. This casts further doubt on whether Web search engines can be used reliably for cross-sectional webometric studies.

The database search problem: a question of rational decision making.

Science.gov (United States)

Gittelson, S; Biedermann, A; Bozza, S; Taroni, F

2012-10-10

This paper applies probability and decision theory in the graphical interface of an influence diagram to study the formal requirements of rationality which justify the individualization of a person found through a database search. The decision-theoretic part of the analysis studies the parameters that a rational decision maker would use to individualize the selected person. The modeling part (in the form of an influence diagram) clarifies the relationships between this decision and the ingredients that make up the database search problem, i.e., the results of the database search and the different pairs of propositions describing whether an individual is at the source of the crime stain. These analyses evaluate the desirability associated with the decision of 'individualizing' (and 'not individualizing'). They point out that this decision is a function of (i) the probability that the individual in question is, in fact, at the source of the crime stain (i.e., the state of nature), and (ii) the decision maker's preferences among the possible consequences of the decision (i.e., the decision maker's loss function). We discuss the relevance and argumentative implications of these insights with respect to recent comments in specialized literature, which suggest points of view that are opposed to the results of our study. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Using a Google Search Appliance (GSA) to search digital library collections: a case study of the INIS Collection Search

OpenAIRE

Savic, Dobrica

2014-01-01

Libraries are facing many challenges today. In addition to diminishing funding and increased user expectations, the use of classic library catalogues is becoming an additional challenge. Library users require fast and easy access to information resources regardless whether the format used is paper or electronic. Google search, with its speed and simplicity, set up a new standard for information retrieval which is hard to achieve with the previous generation of library search facilities. Put i...

Clinician search behaviors may be influenced by search engine design.

Science.gov (United States)

Lau, Annie Y S; Coiera, Enrico; Zrimec, Tatjana; Compton, Paul

2010-06-30

Searching the Web for documents using information retrieval systems plays an important part in clinicians' practice of evidence-based medicine. While much research focuses on the design of methods to retrieve documents, there has been little examination of the way different search engine capabilities influence clinician search behaviors. Previous studies have shown that use of task-based search engines allows for faster searches with no loss of decision accuracy compared with resource-based engines. We hypothesized that changes in search behaviors may explain these differences. In all, 75 clinicians (44 doctors and 31 clinical nurse consultants) were randomized to use either a resource-based or a task-based version of a clinical information retrieval system to answer questions about 8 clinical scenarios in a controlled setting in a university computer laboratory. Clinicians using the resource-based system could select 1 of 6 resources, such as PubMed; clinicians using the task-based system could select 1 of 6 clinical tasks, such as diagnosis. Clinicians in both systems could reformulate search queries. System logs unobtrusively capturing clinicians' interactions with the systems were coded and analyzed for clinicians' search actions and query reformulation strategies. The most frequent search action of clinicians using the resource-based system was to explore a new resource with the same query, that is, these clinicians exhibited a "breadth-first" search behaviour. Of 1398 search actions, clinicians using the resource-based system conducted 401 (28.7%, 95% confidence interval [CI] 26.37-31.11) in this way. In contrast, the majority of clinicians using the task-based system exhibited a "depth-first" search behavior in which they reformulated query keywords while keeping to the same task profiles. Of 585 search actions conducted by clinicians using the task-based system, 379 (64.8%, 95% CI 60.83-68.55) were conducted in this way. This study provides evidence that

Charging/discharging processes in nanocrystaline MOS structures - Theoretical study

International Nuclear Information System (INIS)

Tanous, D; Mazurak, A; Majkusiak, B

2016-01-01

We present the study of impact of some parameters of the metal-insulator-semiconductor structure with nanocrystals embedded in the insulator layer on the current-voltage and capacitance-voltage characteristics with the bias voltage ramp rate as a parameter. The developed model is used as a tool for theoretical understanding the physics behind charging and discharging processes in the considered structures. (paper)

Experimental implementation of a quantum random-walk search algorithm using strongly dipolar coupled spins

International Nuclear Information System (INIS)

Lu Dawei; Peng Xinhua; Du Jiangfeng; Zhu Jing; Zou Ping; Yu Yihua; Zhang Shanmin; Chen Qun

2010-01-01

An important quantum search algorithm based on the quantum random walk performs an oracle search on a database of N items with O(√(phN)) calls, yielding a speedup similar to the Grover quantum search algorithm. The algorithm was implemented on a quantum information processor of three-qubit liquid-crystal nuclear magnetic resonance (NMR) in the case of finding 1 out of 4, and the diagonal elements' tomography of all the final density matrices was completed with comprehensible one-dimensional NMR spectra. The experimental results agree well with the theoretical predictions.

Theoretical Studies in Elementary Particle Physics

Energy Technology Data Exchange (ETDEWEB)

Collins, John C.; Roiban, Radu S

2013-04-01

This final report summarizes work at Penn State University from June 1, 1990 to April 30, 2012. The work was in theoretical elementary particle physics. Many new results in perturbative QCD, in string theory, and in related areas were obtained, with a substantial impact on the experimental program.

Faceted Search

CERN Document Server

Tunkelang, Daniel

2009-01-01

We live in an information age that requires us, more than ever, to represent, access, and use information. Over the last several decades, we have developed a modern science and technology for information retrieval, relentlessly pursuing the vision of a "memex" that Vannevar Bush proposed in his seminal article, "As We May Think." Faceted search plays a key role in this program. Faceted search addresses weaknesses of conventional search approaches and has emerged as a foundation for interactive information retrieval. User studies demonstrate that faceted search provides more

Study of Search Engine Transaction Logs Shows Little Change in How Users use Search Engines. A review of: Jansen, Bernard J., and Amanda Spink. “How Are We Searching the World Wide Web? A Comparison of Nine Search Engine Transaction Logs.” Information Processing & Management 42.1 (2006: 248‐263.

Directory of Open Access Journals (Sweden)

David Hook

2006-09-01

Full Text Available Objective – To examine the interactions between users and search engines, and how they have changed over time. Design – Comparative analysis of search engine transaction logs. Setting – Nine major analyses of search engine transaction logs. Subjects – Nine web search engine studies (4 European, 5 American over a seven‐year period, covering the search engines Excite, Fireball, AltaVista, BWIE and AllTheWeb. Methods – The results from individual studies are compared by year of study for percentages of single query sessions, one term queries, operator (and, or, not, etc. usage and single result page viewing. As well, the authors group the search queries into eleven different topical categories and compare how the breakdown has changed over time. Main Results – Based on the percentage of single query sessions, it does not appear that the complexity of interactions has changed significantly for either the U.S.‐based or the European‐based search engines. As well, there was little change observed in the percentage of one‐term queries over the years of study for either the U.S.‐based or the European‐based search engines. Few users (generally less than 20% use Boolean or other operators in their queries, and these percentages have remained relatively stable. One area of noticeable change is in the percentage of users viewing only one results page, which has increased over the years of study. Based on the studies of the U.S.‐based search engines, the topical categories of ‘People, Place or Things’ and ‘Commerce, Travel, Employment or Economy’ are becoming more popular, while the categories of ‘Sex and Pornography’ and ‘Entertainment or Recreation’ are declining. Conclusions – The percentage of users viewing only one results page increased during the years of the study, while the percentages of single query sessions, oneterm sessions and operator usage remained stable. The increase in single result page viewing

Further investigation on adaptive search

Directory of Open Access Journals (Sweden)

Ming Hong Pi

2014-05-01

Full Text Available Adaptive search is one of the fastest fractal compression algorithms and has gained great success in many industrial applications. By substituting the luminance offset by the range block mean, the authors create a completely new version for both the encoding and decoding algorithms. In this paper, theoretically, they prove that the proposed decoding algorithm converges at least as fast as the existing decoding algorithms using the luminance offset. In addition, they prove that the attractor of the decoding algorithm can be represented by a linear combination of range-averaged images. These theorems are very important contributions to the theory and applications of fractal image compression. As a result, the decoding image can be represented as the sum of the DC and AC component images, which is similar with discrete cosine transform or wavelet transform. To further speed up this algorithm and reduce the complexity of range and domain blocks matching, they propose two improvements in this paper, that is, employing the post-quantisation and geometric neighbouring local search to replace the currently used pre-quantisation and the global search, respectively. The corresponding experimental results show the proposed encoding and decoding algorithms can provide a better performance compared with the existing algorithms.

Gravitational wave searches using the DSN (Deep Space Network)

International Nuclear Information System (INIS)

Nelson, S.J.; Armstrong, J.W.

1988-01-01

The Deep Space Network Doppler spacecraft link is currently the only method available for broadband gravitational wave searches in the 0.01 to 0.001 Hz frequency range. The DSN's role in the worldwide search for gravitational waves is described by first summarizing from the literature current theoretical estimates of gravitational wave strengths and time scales from various astrophysical sources. Current and future detection schemes for ground based and space based detectors are then discussed. Past, present, and future planned or proposed gravitational wave experiments using DSN Doppler tracking are described. Lastly, some major technical challenges to improve gravitational wave sensitivities using the DSN are discussed

Theoretical study of thorium monoxide for the electron electric dipole moment search: Electronic properties of H{sup 3}Δ{sub 1} in ThO

Energy Technology Data Exchange (ETDEWEB)

Skripnikov, L. V., E-mail: leonidos239@gmail.com; Titov, A. V. [B.P. Konstantinov Petersburg Nuclear Physics Institute, Gatchina, Leningrad district 188300 (Russian Federation); Department of Physics, Saint Petersburg State University, Saint Petersburg, Petrodvoretz 198504 (Russian Federation)

2015-01-14

Recently, improved limits on the electron electric dipole moment, and dimensionless constant, k{sub T,P}, characterizing the strength of the T,P-odd pseudoscalar–scalar electron–nucleus neutral current interaction in the H{sup 3}Δ{sub 1} state of ThO molecule were obtained by the ACME collaboration [J. Baron et al., Science 343, 269 (2014)]. The interpretation of the experiment in terms of these fundamental quantities is based on the results of theoretical study of appropriate ThO characteristics, the effective electric field acting on electron, E{sub eff}, and a parameter of the T,P-odd pseudoscalar–scalar interaction, W{sub T,P}, given in Skripnikov et al. [J. Chem. Phys. 139, 221103 (2013)] by St. Petersburg group. To reduce the uncertainties of the given limits, we report improved calculations of the molecular state–specific quantities E{sub eff}, 81.5 GV/cm, and W{sub T,P}, 112 kHz, with the uncertainty within 7% of the magnitudes. Thus, the values recommended to use for the upper limits of the quantities are 75.8 GV/cm and 104 kHz, correspondingly. The hyperfine structure constant, molecule-frame dipole moment of the H{sup 3}Δ{sub 1} state, and the H{sup 3}Δ{sub 1} → X{sup 1}Σ{sup +} transition energy which, in general, can serve as a measure of reliability of the obtained E{sub eff} and W{sub T,P} values are also calculated. In addition, we report the first calculation of g-factor for the H{sup 3}Δ{sub 1} state of ThO. The results are compared to the earlier experimental and theoretical studies, and a detailed analysis of uncertainties of the calculations is given.

Philosophical and theoretical content of the nursing discipline in academic education: A critical interpretive synthesis.

Science.gov (United States)

Rega, Maria Luisa; Telaretti, Fabia; Alvaro, Rosaria; Kangasniemi, Mari

2017-10-01

Nursing as clinical practice, management and research are based on nursing philosophy and theory. Thus, the philosophical and theoretical content is required to be incorporated in academic education in order to enable nurses' skills for reflection, analysis, and thinking about the profession. The aim of this review was to describe what is known of the philosophical and theoretical content of the nursing discipline within academic education. A critical interpretive synthesis (CIS). Electronic searches were performed across four databases, CINAHL, Scopus, Medline, and Web of Science, for papers published in English from 1980 to 2016. The selection of original articles was based on stages, and inclusion and exclusion criteria were used. Quality of the selected papers were evaluated by method sensitive appraisal criteria. The five phases of CIS were used to combine the selected data. The searches resulted 9148 titles, whereas 13 were selected. Nurses need philosophical and theoretical education in order to be aware of human health and explain the complexity of the human experience of illness. The philosophy of science, the philosophy of care, and theory development were highlighted as the key contents in nursing academic education as these subjects are central to the discipline that ensures that nurses acquire advanced skills. A model was developed that linked disciplinary issues the progression nursing science through the influence of advanced skills. Based on the findings in this study the philosophical and theoretical content of nursing discipline crates a basis for the academic education and enables a professional and exclusive vision for nurses. It provides an overall understanding of people's lives and support nurses to achieve deeper awareness of the meaning of illness and health in a person lifespan what is needed on the evidence-based decision making. Copyright © 2017 Elsevier Ltd. All rights reserved.

Micro sociological study of family relationships: heuristic potential theoretical principles

Directory of Open Access Journals (Sweden)

O. P. Zolotnyik

2015-03-01

Full Text Available This article is devoted to demonstrate the heuristic potential of theoretical principles by microsoсiological analysis of one of the indicators of family – family relations. Theoretical analysis of the interaction experience is quite large, but there is the question about it’s possibility to describe the specifics of that relationship that arise in family interaction. The study of family relationships requires an integrated approach to the comprehension of many related components: system of spouses value orientations, family life cycle, socio­economic living conditions of couple. However, the accentuation exactly on action­behavioral aspect allows to make assumptions about correlations between: success of family interaction and microclimate in the family; satisfaction level of interpersonal interaction and overall satisfaction with marriage, familiarity of family interaction and density of childbearing, and so on. The presentation of microsoсiological theoretical achievements will be carried out of sociological schools, orientations and their members that are the most popular references in this area. this paper will presents the theory of exchange, supporters of symbolic interactionism, dramatic and etnometodological approach and family systems theory.

Theoretical study of the lowest-lying electronic states of Aluminium monoiodide

International Nuclear Information System (INIS)

Taher, F.; Kabbani, A.; Ani-El Houte, W.

2004-01-01

Full text.The spectroscopic study of Aluminium monohalides, especially the Aluminium monoiodide, is important for monitoring such species in high temperature fast-flow reactors. Theoretical calculations of AlI are not available, whereas several studies have been done for the other aluminium monohalides. In this work, CAS-SCF/MRCI calculations are performed for the lowest-lying electronic states of AlI in a range of internuclear distance between 2.30 A and 2.80 A. Ab-initio calculations have been effectuated by using the computational chemistry program Molpro. The basis set used in this study for aluminium atom is that used by Langhoff for aluminium monohalides, of contractions using atomic natural orbitals and a pseudopotential is used for iode. Accurate theoretical spectroscopic constants and potential curves are obtained for the ground state X 1 Σ + and the first excited states a 3 Π and A 1 Π. The calculated values of Te, ωe, ωexe and re of these states are compatible with the experimental results. An ordering of states is represented for the lowest five predicted singlet and lowest five predicted triplet states. These results provide a big support to determine the analogy in the ordering of the electronic states in AlF, AlBr and AlI respectively at lower energies. These theoretical results identify a set of electronic singlet and triplet states unobserved experimentally

Experimental and theoretical study of steam condensation induced water hammer phenomena

International Nuclear Information System (INIS)

Barna, Imre Ferenc; Baranyai, Gabor; Ezsoel, Gyoergy

2009-01-01

We investigate steam condensation induced water hammer (waha) phenomena and present experimental and theoretical results. Some of the experiments were performed in the PMK-2 facility, which is a full-pressure thermohydraulic model of the nuclear power plant of VVER-440/312 type and located in the Atomic Energy Research Institute Budapest, Hungary. Other experiments were done in the ROSA facility in Japan. On the theoretical side waha is studied and analyzed with the WAHA3 model based on two-phase flow six first-order partial differential equations that present one dimensional, surface averaged mass, momentum and energy balances. A second order accurate high-resolution shock-capturing numerical scheme was applied with different kind of limiters in the numerical calculations. The applied two-fluid model shows some similarities to Relap5 which is widely used in the nuclear industry to simulate nuclear power plant accidents. Experimentally measured and theoretically calculated waha pressure peaks are in qualitative agreement. (author)

Impact of jet veto resummation on slepton searches

International Nuclear Information System (INIS)

Tackmann, Frank J.; Waalewijn, Wouter J.; Nikhef, Amsterdam; Zeune, Lisa

2016-03-01

Several searches for new physics at the LHC require a fixed number of signal jets, vetoing events with additional jets from QCD radiation. As the probed scale of new physics gets much larger than the jet-veto scale, such jet vetoes strongly impact the QCD perturbative series, causing nontrivial theoretical uncertainties. We consider slepton pair production with 0 signal jets, for which we perform the resummation of jet-veto logarithms and study its impact. Currently, the experimental exclusion limits take the jet-veto cut into account by extrapolating to the inclusive cross section using parton shower Monte Carlos. Our results indicate that the associated theoretical uncertainties can be large, and when taken into account have a sizeable impact already on present exclusion limits. This is improved by performing the resummation to higher order, which allows us to obtain accurate predictions even for high slepton masses. For the interpretation of the experimental results to benefit from improved theory predictions, it would be useful for the experimental analyses to also provide limits on the unfolded visible 0-jet cross section.

Development of a theoretical framework of factors affecting patient safety incident reporting: a theoretical review of the literature.

Science.gov (United States)

Archer, Stephanie; Hull, Louise; Soukup, Tayana; Mayer, Erik; Athanasiou, Thanos; Sevdalis, Nick; Darzi, Ara

2017-12-27

The development and implementation of incident reporting systems within healthcare continues to be a fundamental strategy to reduce preventable patient harm and improve the quality and safety of healthcare. We sought to identify factors contributing to patient safety incident reporting. To facilitate improvements in incident reporting, a theoretical framework, encompassing factors that act as barriers and enablers ofreporting, was developed. Embase, Ovid MEDLINE(R) and PsycINFO were searched to identify relevant articles published between January 1980 and May 2014. A comprehensive search strategy including MeSH terms and keywords was developed to identify relevant articles. Data were extracted by three independent researchers; to ensure the accuracy of data extraction, all studies eligible for inclusion were rescreened by two reviewers. The literature search identified 3049 potentially eligible articles; of these, 110 articles, including >29 726 participants, met the inclusion criteria. In total, 748 barriers were identified (frequency count) across the 110 articles. In comparison, 372 facilitators to incident reporting and 118 negative cases were identified. The top two barriers cited were fear of adverse consequences (161, representing 21.52% of barriers) and process and systems of reporting (110, representing 14.71% of barriers). In comparison, the top two facilitators were organisational (97, representing 26.08% of facilitators) and process and systems of reporting (75, representing 20.16% of facilitators). A wide range of factors contributing to engagement in incident reporting exist. Efforts that address the current tendency to under-report must consider the full range of factors in order to develop interventions as well as a strategic policy approach for improvement. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Why search for double beta decay?

International Nuclear Information System (INIS)

Kayser, B.

1988-01-01

Searching for neutrinoless double beta decay is the only known practical method for trying to determine whether neutrinos are their own antiparticles. The theoretical motivation for supposing that they may indeed be their own antiparticles is described. The reason that it is so difficult to ascertain experimentally whether they are or are not is explained, as is the special sensitivity of neutrinoless double beta decay. The potential implications of the observation of this reaction for neutrino mass and for the physics of neutrinos is discussed

The pressure distribution for biharmonic transmitting array: theoretical study

Science.gov (United States)

Baranowska, A.

2005-03-01

The aim of the paper is theoretical analysis of the finite amplitude waves interaction problem for the biharmonic transmitting array. We assume that the array consists of 16 circular pistons of the same dimensions that regrouped in two sections. Two different arrangements of radiating elements were considered. In this situation the radiating surface is non-continuous without axial symmetry. The mathematical model was built on the basis of the Khokhlov - Zabolotskaya - Kuznetsov (KZK) equation. To solve the problem the finite-difference method was applied. On-axis pressure amplitude for different frequency waves as a function of distance from the source, transverse pressure distribution of these waves at fixed distances from the source and pressure amplitude distribution for them at fixed planes were examined. Especially changes of normalized pressure amplitude for difference frequency were studied. The paper presents mathematical model and some results of theoretical investigations obtained for different values of source parameters.

Accessing Suicide-Related Information on the Internet: A Retrospective Observational Study of Search Behavior

Science.gov (United States)

2013-01-01

Background The Internet’s potential impact on suicide is of major public health interest as easy online access to pro-suicide information or specific suicide methods may increase suicide risk among vulnerable Internet users. Little is known, however, about users’ actual searching and browsing behaviors of online suicide-related information. Objective To investigate what webpages people actually clicked on after searching with suicide-related queries on a search engine and to examine what queries people used to get access to pro-suicide websites. Methods A retrospective observational study was done. We used a web search dataset released by America Online (AOL). The dataset was randomly sampled from all AOL subscribers’ web queries between March and May 2006 and generated by 657,000 service subscribers. Results We found 5526 search queries (0.026%, 5526/21,000,000) that included the keyword "suicide". The 5526 search queries included 1586 different search terms and were generated by 1625 unique subscribers (0.25%, 1625/657,000). Of these queries, 61.38% (3392/5526) were followed by users clicking on a search result. Of these 3392 queries, 1344 (39.62%) webpages were clicked on by 930 unique users but only 1314 of those webpages were accessible during the study period. Each clicked-through webpage was classified into 11 categories. The categories of the most visited webpages were: entertainment (30.13%; 396/1314), scientific information (18.31%; 240/1314), and community resources (14.53%; 191/1314). Among the 1314 accessed webpages, we could identify only two pro-suicide websites. We found that the search terms used to access these sites included “commiting suicide with a gas oven”, “hairless goat”, “pictures of murder by strangulation”, and “photo of a severe burn”. A limitation of our study is that the database may be dated and confined to mainly English webpages. Conclusions Searching or browsing suicide-related or pro-suicide webpages was

Accessing suicide-related information on the internet: a retrospective observational study of search behavior.

Science.gov (United States)

Wong, Paul Wai-Ching; Fu, King-Wa; Yau, Rickey Sai-Pong; Ma, Helen Hei-Man; Law, Yik-Wa; Chang, Shu-Sen; Yip, Paul Siu-Fai

2013-01-11

The Internet's potential impact on suicide is of major public health interest as easy online access to pro-suicide information or specific suicide methods may increase suicide risk among vulnerable Internet users. Little is known, however, about users' actual searching and browsing behaviors of online suicide-related information. To investigate what webpages people actually clicked on after searching with suicide-related queries on a search engine and to examine what queries people used to get access to pro-suicide websites. A retrospective observational study was done. We used a web search dataset released by America Online (AOL). The dataset was randomly sampled from all AOL subscribers' web queries between March and May 2006 and generated by 657,000 service subscribers. We found 5526 search queries (0.026%, 5526/21,000,000) that included the keyword "suicide". The 5526 search queries included 1586 different search terms and were generated by 1625 unique subscribers (0.25%, 1625/657,000). Of these queries, 61.38% (3392/5526) were followed by users clicking on a search result. Of these 3392 queries, 1344 (39.62%) webpages were clicked on by 930 unique users but only 1314 of those webpages were accessible during the study period. Each clicked-through webpage was classified into 11 categories. The categories of the most visited webpages were: entertainment (30.13%; 396/1314), scientific information (18.31%; 240/1314), and community resources (14.53%; 191/1314). Among the 1314 accessed webpages, we could identify only two pro-suicide websites. We found that the search terms used to access these sites included "commiting suicide with a gas oven", "hairless goat", "pictures of murder by strangulation", and "photo of a severe burn". A limitation of our study is that the database may be dated and confined to mainly English webpages. Searching or browsing suicide-related or pro-suicide webpages was uncommon, although a small group of users did access websites that contain

Do two heads search better than one? Effects of student collaboration on web search behavior and search outcomes.

NARCIS (Netherlands)

Lazonder, Adrianus W.

2005-01-01

This study compared Pairs of students with Single students in web search tasks. The underlying hypothesis was that peer-to-peer collaboration encourages students to articulate their thoughts, which in turn has a facilitative effect on the regulation of the search process as well as search outcomes.

Masculinities in School Physical education: theoretical issues and political horizons

Directory of Open Access Journals (Sweden)

Leandro Teofilo de Brito

2017-05-01

Full Text Available Based on the recognition of the urgency of the theme of gender and sexuality within the approach of the difference inclusion in School Physical education by academic research, in this article, we focus the notion of masculinity. We present and problematize the Raewyn Connell‟s theory of hegemonic masculinity, as well as the queer perspective, theoretical references identified in the literature review, which is also exposed. Based on the proposal of Jacques Derrida‟s deconstruction and the notion of performative gender, as developed by Judith Butler, we conclude this reflection with the proposition of normalizing masculinity and queer masculinity as search operators, in the theoretical and political will to favor openness to a more radical inclusion in research and lessons of SPE.

Theoretical study of fractal growth and stability on surface

DEFF Research Database (Denmark)

Dick, Veronika V.; Solov'yov, Ilia; Solov'yov, Andrey V.

2009-01-01

We perform a theoretical study of the fractal growing process on surface by using the deposition, diffusion, aggregation method. We present a detailed analysis of the post-growth processes occurring in a nanofractal on surface. For this study we developed a method which describes the internal...... dynamics of particles in a fractal and accounts for their diffusion and detachment. We demonstrate that these kinetic processes are responsible for the formation of the final shape of the islands on surface after the post-growth relaxation....

Theoretical and experimental study of resonant inelastic X-ray scattering for NiO

International Nuclear Information System (INIS)

Kotani, A.; Matsubara, M.; Uozumi, T.; Ghiringhelli, G.; Fracassi, F.; Dallera, C.; Tagliaferri, A.; Brookes, N.B.; Braicovich, L.

2006-01-01

Resonant inelastic X-ray scattering (RIXS) spectra for Ni 2p to 3d excitation and 3d to 2p de-excitation of NiO are studied both theoretically and experimentally. Theoretical calculations with a single impurity Anderson model (SIAM) describe the charge transfer (CT) and d-d excitations in RIXS, and detailed study is made for the CT energy. High resolution RIXS measurements reveal the precise d-d excitation structure and its polarization dependence, and they are well reproduced by the SIAM calculation

Theoretical Study on the Flow of Refilling Stage in a Safety Injection Tank

Energy Technology Data Exchange (ETDEWEB)

Park, Jun Sang [Halla Univ. Daejeon (Korea, Republic of)

2017-10-15

In this study, a theoretical analysis was performed to the flow of refilling stage in a safety injection tank, which is the core cooling system of nuclear power plant in an emergency. A theoretical model was proposed with a nonlinear governing equation defining on the flow of the refilling process of the coolant. Utilizing the Taylor-series expansion, the 1st - order approximation flow equation was obtained, along with its analytic solution of closed type, which could predict accurately the variations of free surface height and flow rate of the coolant. The availability of theoretical result was confirmed by comparing with previous experimental results.

Theoretical and experimental studies of elementary physics

International Nuclear Information System (INIS)

Bodek, A.; Ferbel, T.; Melissinos, A.C.; Slattery, P.; Tipton, P.; Das, A.; Hagen, C.R.; Rajeev, S.G.; Okubo, S.; Orr, L.

1993-01-01

The various components of the high-energy physics research program at the University of Rochester are presented. (I)Fixed-target experimentation at FNAL includes studies of direct photon production by p and π on H, Be, and Cu, and hybrid mesons and other physics issues in Coulomb excitation at high energies. (II)The status of the GEM (Gammas, Electrons, and Muons) Experiment at the SSC is given. (III)The D-Zero experiment at FNAL is reviewed. (IV)Deep inelastic lepton--nucleon scattering experiments are summarized: electron scattering experiments at SLAC, FNAL neutrino quad triplet runs, FNAL neutrino sign selected experiments, and SDC cosmic ray test and test beam calibration. (V)Studies of nonlinear QED at SLAC concentrated on a study of QED at critical field strength in intense laser--high-energy electron collisions. (VI)Development work on the Collider Detector at Fermilab (CDF) emphasized the CDF silicon vertex detector, the end plug calorimeter, and the SDC tile/fiber calorimetry. (VII)The theoretical physics effort is sketched

Model Independent Search For New Physics At The Tevatron

Energy Technology Data Exchange (ETDEWEB)

Choudalakis, Georgios [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

2008-04-01

The Standard Model of elementary particles can not be the final theory. There are theoretical reasons to expect the appearance of new physics, possibly at the energy scale of few TeV. Several possible theories of new physics have been proposed, each with unknown probability to be confirmed. Instead of arbitrarily choosing to examine one of those theories, this thesis is about searching for any sign of new physics in a model-independent way. This search is performed at the Collider Detector at Fermilab (CDF). The Standard Model prediction is implemented in all final states simultaneously, and an array of statistical probes is employed to search for significant discrepancies between data and prediction. The probes are sensitive to overall population discrepancies, shape disagreements in distributions of kinematic quantities of final particles, excesses of events of large total transverse momentum, and local excesses of data expected from resonances due to new massive particles. The result of this search, first in 1 fb^-1 and then in 2 fb^-1, is null, namely no considerable evidence of new physics was found.

Theoretical aspects of marketing management of consumer behavior

Directory of Open Access Journals (Sweden)

Danilenko Evgen

2015-11-01

Full Text Available The essence of consumer behavior finds expression in the actions of people under the influence of environmental factors and internal psychological or physical needs that arise in the process of life and socialization and are accompanied by information search, selection, acquisition, use of goods or services and getting rid of them. The article presents a synthesis of current theoretical terminology provisions on identification and definition of the nature of consumer behavior, allowing to improve conceptual and categorical apparatus by determining definitions of "marketing management", "consumer behavior".

Performance comparison of a new hybrid conjugate gradient method under exact and inexact line searches

Science.gov (United States)

Ghani, N. H. A.; Mohamed, N. S.; Zull, N.; Shoid, S.; Rivaie, M.; Mamat, M.

2017-09-01

Conjugate gradient (CG) method is one of iterative techniques prominently used in solving unconstrained optimization problems due to its simplicity, low memory storage, and good convergence analysis. This paper presents a new hybrid conjugate gradient method, named NRM1 method. The method is analyzed under the exact and inexact line searches in given conditions. Theoretically, proofs show that the NRM1 method satisfies the sufficient descent condition with both line searches. The computational result indicates that NRM1 method is capable in solving the standard unconstrained optimization problems used. On the other hand, the NRM1 method performs better under inexact line search compared with exact line search.

Graph theoretical ordering of structures as a basis for systematic searches for regularities in molecular data

International Nuclear Information System (INIS)

Randic, M.; Wilkins, C.L.

1979-01-01

Selected molecular data on alkanes have been reexamined in a search for general regularities in isomeric variations. In contrast to the prevailing approaches concerned with fitting data by searching for optimal parameterization, the present work is primarily aimed at established trends, i.e., searching for relative magnitudes and their regularities among the isomers. Such an approach is complementary to curve fitting or correlation seeking procedures. It is particularly useful when there are incomplete data which allow trends to be recognized but no quantitative correlation to be established. One proceeds by first ordering structures. One way is to consider molecular graphs and enumerate paths of different length as the basic graph invariant. It can be shown that, for several thermodynamic molecular properties, the number of paths of length two (p 2 ) and length three (p 3 ) are critical. Hence, an ordering based on p 2 and p 3 indicates possible trends and behavior for many molecular properties, some of which relate to others, some which do not. By considering a grid graph derived by attributing to each isomer coordinates (p 2 ,p 3 ) and connecting points along the coordinate axis, one obtains a simple presentation useful for isomer structural interrelations. This skeletal frame is one upon which possible trends for different molecular properties may be conveniently represented. The significance of the results and their conceptual value is discussed. 16 figures, 3 tables

Search Advertising

OpenAIRE

Cornière (de), Alexandre

2016-01-01

Search engines enable advertisers to target consumers based on the query they have entered. In a framework with horizontal product differentiation, imperfect product information and in which consumers incur search costs, I study a game in which advertisers have to choose a price and a set of relevant keywords. The targeting mechanism brings about three kinds of efficiency gains, namely lower search costs, better matching, and more intense product market price-competition. A monopolistic searc...

Short communication. Economics of natural resources: in search of a unified theoretical framework

Energy Technology Data Exchange (ETDEWEB)

Romero, C.

2012-11-01

This paper proposes a unified theoretical framework for dealing with the optimum economic use of any type of natural resource. After formulating and economically interpreting the unified framework, the basic rules governing the economic exploitation of the different natural resources can be easily obtained by particularizing the different values of its basic parameters. Taking this approach, it is easy to understand what commonalities there are, in terms of economic logic, between the different types of natural resources. This considerably increases the amount of consilience and understanding about the discipline. (Author) 8 refs.

How to adapt broad-band gravitational-wave searches for r-modes

International Nuclear Information System (INIS)

Owen, Benjamin J.

2010-01-01

Up to now there has been no search for gravitational waves from the r-modes of neutron stars in spite of the theoretical interest in the subject. Several oddities of r-modes must be addressed to obtain an observational result: The gravitational radiation field is dominated by the mass current (gravitomagnetic) quadrupole rather than the usual mass quadrupole, and the consequent difference in polarization affects detection statistics and parameter estimation. To astrophysically interpret a detection or upper limit it is necessary to convert the gravitational-wave amplitude to an r-mode amplitude. Also, it is helpful to know indirect limits on gravitational-wave emission to gauge the interest of various searches. Here I address these issues, thereby providing the ingredients to adapt broad-band searches for continuous gravitational waves to obtain r-mode results. I also show that searches of existing data can already have interesting sensitivities to r-modes.

State-of-the-Art: Research Theoretical Framework of Information Systems Implementation Research in the Health Sector in Sub-Saharan Africa

DEFF Research Database (Denmark)

Tetteh, Godwin Kofi

2014-01-01

This study is about the state-of-the-art of reference theories and theoretical framework of information systems implementation research in the health industry in the Sub-Saharan countries from a process perspective. A process – variance framework, Poole et al, (2000), Markus & Robey, (1988......) and Shaw & Jarvenpaa, (1997) is employed to examine reference theories employed in research conducted on information systems implementation in the health sector in the Sub-Saharan region and published between 2003 and 2013. Using a number of key words and searching on a number of databases, EBSCO, CSA...... the process theoretical framework to enhance our insight into successful information systems implementation in the region. It is our optimism that the process based theoretical framework will be useful for, information system practitioners and organisational managers and researchers in the health sector...

A theoretical study of rotatable renewable energy system for stratospheric airship

International Nuclear Information System (INIS)

Lv, Mingyun; Li, Jun; Zhu, Weiyu; Du, Huafei; Meng, Junhui; Sun, Kangwen

2017-01-01

Highlights: • A new rotatable renewable energy system is designed for stratospheric airship. • A theoretical model of optimal rotation angle and required area are studied. • The effects of latitude and date on output energy per day are investigated. • The advantages of the rotatable renewable energy system are studied. - Abstract: Renewable energy system is very critical for solving the energy problem of a long endurance stratospheric airship. Output performance of the traditional solar array fixed on the upper surface of the airship remains to be improved to reduce the area and weight of renewable energy system. Inspired by the solar tracking system and kirigami, a rotatable renewable energy system (mainly including solar array) is designed to improve the current status of the energy system. The advantages of the rotatable solar array are studied using a MATLAB computer program based on the theoretical model established in this paper. The improvements in output energy and required area of the solar array were compared between the traditional airship and improved one. Studies had shown that the rotatable renewable energy system made the total weight of energy system decreased by 1000 kg when the maximum design speed of the airship was greater than 22 m/s. The results demonstrate that the rotatable renewable energy system for the airship can be a good way to improve the output performance of solar array, and the conceptual design and theoretical model suggest a pathway towards solving the energy problem of a stratospheric airship.

Experimental studies of caesium iodide aerosol condensation: theoretical interpretation

International Nuclear Information System (INIS)

Beard, A.M.; Benson, C.G.; Horton, K.D.; Buckle, E.R.

1990-07-01

Caesium iodide is predicted to be a significant source of fission product aerosols during the course of a severe accident in a pressurised water reactor (PWR). The nucleation and growth of caesium iodide aerosols have been studied using a plume chamber and the results compared with theoretical values calculated using the approach developed by Buckle for aerosol nucleation. The morphology of the particles was studied using scanning electron microscopy (SEM) and transmission optical microscopy (TOM), whilst the particle size distributions were determined from differential mobility (DMPS) and aerodynamic (APS) measurements. (author)

Strong correlation effects in theoretical STM studies of magnetic adatoms

Science.gov (United States)

Dang, Hung T.; dos Santos Dias, Manuel; Liebsch, Ansgar; Lounis, Samir

2016-03-01

We present a theoretical study for the scanning tunneling microscopy (STM) spectra of surface-supported magnetic nanostructures, incorporating strong correlation effects. As concrete examples, we study Co and Mn adatoms on the Cu(111) surface, which are expected to represent the opposite limits of Kondo physics and local moment behavior, using a combination of density functional theory and both quantum Monte Carlo and exact diagonalization impurity solvers. We examine in detail the effects of temperature T , correlation strength U , and impurity d electron occupancy Nd on the local density of states. We also study the effective coherence energy scale, i.e., the Kondo temperature TK, which can be extracted from the STM spectra. Theoretical STM spectra are computed as a function of STM tip position relative to each adatom. Because of the multiorbital nature of the adatoms, the STM spectra are shown to consist of a complicated superposition of orbital contributions, with different orbital symmetries, self-energies, and Kondo temperatures. For a Mn adatom, which is close to half-filling, the STM spectra are featureless near the Fermi level. On the other hand, the quasiparticle peak for a Co adatom gives rise to strongly position-dependent Fano line shapes.

Developing optimal search strategies for detecting clinically sound prognostic studies in MEDLINE: an analytic survey

Directory of Open Access Journals (Sweden)

Haynes R Brian

2004-06-01

Full Text Available Abstract Background Clinical end users of MEDLINE have a difficult time retrieving articles that are both scientifically sound and directly relevant to clinical practice. Search filters have been developed to assist end users in increasing the success of their searches. Many filters have been developed for the literature on therapy and reviews but little has been done in the area of prognosis. The objective of this study is to determine how well various methodologic textwords, Medical Subject Headings, and their Boolean combinations retrieve methodologically sound literature on the prognosis of health disorders in MEDLINE. Methods An analytic survey was conducted, comparing hand searches of journals with retrievals from MEDLINE for candidate search terms and combinations. Six research assistants read all issues of 161 journals for the publishing year 2000. All articles were rated using purpose and quality indicators and categorized into clinically relevant original studies, review articles, general papers, or case reports. The original and review articles were then categorized as 'pass' or 'fail' for methodologic rigor in the areas of prognosis and other clinical topics. Candidate search strategies were developed for prognosis and run in MEDLINE – the retrievals being compared with the hand search data. The sensitivity, specificity, precision, and accuracy of the search strategies were calculated. Results 12% of studies classified as prognosis met basic criteria for scientific merit for testing clinical applications. Combinations of terms reached peak sensitivities of 90%. Compared with the best single term, multiple terms increased sensitivity for sound studies by 25.2% (absolute increase, and increased specificity, but by a much smaller amount (1.1% when sensitivity was maximized. Combining terms to optimize both sensitivity and specificity achieved sensitivities and specificities of approximately 83% for each. Conclusion Empirically derived

Search for Muon neutrino → Tau neutrino oscillations motivation and feasibility

International Nuclear Information System (INIS)

Zacek, V.

1988-01-01

Theoretical prejudices derived from solar-neutrino matter oscillations and assumptions of neutrino mass hierarchies suggest, that neutrino-oscillations are observable in laboratory with mass parameters of Δm 2 = 10 -3 -10 4 eV 2 . In particular Muon neutrino → Tau neutrino appearance searches at accelerators seem strongly motivated

Ambiguities of theoretical parameters and CP or T violation in neutrino factories

International Nuclear Information System (INIS)

Koike, Masafumi; Ota, Toshihiko; Sato, Joe

2002-01-01

We study the sensitivity to the CP- or T-violation search in the presence of ambiguities of the theoretical parameters. Three generations of neutrinos are considered. The parameters whose ambiguities are considered are the differences of the squared masses, the mixing angles, and the density of matter. We first consider the statistics that are sensitive to the genuine CP-violation effect originating from the imaginary coupling. No ambiguity of the parameters is considered in this part. It is argued that the widely adopted usual statistics are not necessarily sensitive to the genuine CP-violation effect. Two statistics that are sensitive to the imaginary coupling are proposed. The qualitative difference between these statistics and the usual ones are discussed. Next we proceed to the case where the ambiguity of the parameters is present. The sensitivity of the CP-violation search is greatly spoiled when the baseline length is longer than about one thousand kilometers, which turns out to be due to the ambiguity of the matter effect. Thus the CP-violation search by use of CP conjugate channels turns out to require a low energy neutrino and short baseline length. It is also shown that such a loss of sensitivity is avoided by using T-conjugate oscillation channels

African Studies Monographs: Advanced Search

African Journals Online (AJOL)

... containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., archive ((journal OR conference) NOT theses); Search for an exact phrase by putting it in quotes; e.g., "open access publishing"; Exclude a word by prefixing it with - or NOT; e.g. online -politics or online NOT politics ...

A theoretical search for intermetallic compounds and solution phases in the binary system Sn/Zn

Energy Technology Data Exchange (ETDEWEB)

Appen, Joerg von; Dronskowski, Richard; Hack, Klaus

2004-10-06

The binary system Sn/Zn was theoretically investigated by a classical thermodynamic analysis (CALPHAD approach) and by density-functional total-energy calculations on the basis of the LDA/GGA, plane waves/muffin-tin orbitals, and supercell geometries. In harmony with experimental data, both methods agree in that there is only very small solubility between the elements and no formation of a stable intermetallic phase over the entire compositional range. For the hypothetical composition Sn{sub 2}Zn, a total of 30 different crystal structures was quantum-mechanically optimized, and the chemical bondings of Sn{sub 2}Zn adopting the CaF{sub 2} and HgBr{sub 2} structures were analyzed in detail; generally, the more ionic structure types are better suited for the Sn{sub 2}Zn composition than typical intermetallic ones. Theoretical enthalphy-pressure diagrams were generated to explore high-pressure compound formation, and the observed transition pressures between the {alpha}, {beta} and {gamma} allotropes of tin were correctly reproduced by electronic structure theory.

Journal of History and Diplomatic Studies: Advanced Search

African Journals Online (AJOL)

Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

Experimental and theoretical high energy physics research. [UCLA

Energy Technology Data Exchange (ETDEWEB)

Buchanan, Charles D.; Cline, David B.; Byers, N.; Ferrara, S.; Peccei, R.; Hauser, Jay; Muller, Thomas; Atac, Muzaffer; Slater, William; Cousins, Robert; Arisaka, Katsushi

1992-01-01

Progress in the various components of the UCLA High-Energy Physics Research program is summarized, including some representative figures and lists of resulting presentations and published papers. Principal efforts were directed at the following: (I) UCLA hadronization model, PEP4/9 e{sup +}e{sup {minus}} analysis, {bar P} decay; (II) ICARUS and astroparticle physics (physics goals, technical progress on electronics, data acquisition, and detector performance, long baseline neutrino beam from CERN to the Gran Sasso and ICARUS, future ICARUS program, and WIMP experiment with xenon), B physics with hadron beams and colliders, high-energy collider physics, and the {phi} factory project; (III) theoretical high-energy physics; (IV) H dibaryon search, search for K{sub L}{sup 0} {yields} {pi}{sup 0}{gamma}{gamma} and {pi}{sup 0}{nu}{bar {nu}}, and detector design and construction for the FNAL-KTeV project; (V) UCLA participation in the experiment CDF at Fermilab; and (VI) VLPC/scintillating fiber R D.

Beyond the search surface: visual search and attentional engagement.

Science.gov (United States)

Duncan, J; Humphreys, G

1992-05-01

Treisman (1991) described a series of visual search studies testing feature integration theory against an alternative (Duncan & Humphreys, 1989) in which feature and conjunction search are basically similar. Here the latter account is noted to have 2 distinct levels: (a) a summary of search findings in terms of stimulus similarities, and (b) a theory of how visual attention is brought to bear on relevant objects. Working at the 1st level, Treisman found that even when similarities were calibrated and controlled, conjunction search was much harder than feature search. The theory, however, can only really be tested at the 2nd level, because the 1st is an approximation. An account of the findings is developed at the 2nd level, based on the 2 processes of input-template matching and spreading suppression. New data show that, when both of these factors are controlled, feature and conjunction search are equally difficult. Possibilities for unification of the alternative views are considered.

Correction: Experimental and theoretical studies of nanofluid thermal conductivity enhancement: a review

Directory of Open Access Journals (Sweden)

Kleinstreuer Clement

2011-01-01

Full Text Available Abstract Correction to Kleinstreuer C, Feng Y: Experimental and theoretical studies of nanofluid thermal conductivity enhancement: a review. Nanoscale Research Letters 2011, 6:229.

Theoretical Studies of Strongly Interacting Fine Particle Systems

Science.gov (United States)

Fearon, Michael

Available from UMI in association with The British Library. A theoretical analysis of the time dependent behaviour of a system of fine magnetic particles as a function of applied field and temperature was carried out. The model used was based on a theory assuming Neel relaxation with a distribution of particle sizes. This theory predicted a linear variation of S_{max} with temperature and a finite intercept, which is not reflected by experimental observations. The remanence curves of strongly interacting fine-particle systems were also investigated theoretically. It was shown that the Henkel plot of the dc demagnetisation remanence vs the isothermal remanence is a useful representation of interactions. The form of the plot was found to be a reflection of the magnetic and physical microstructure of the material, which is consistent with experimental data. The relationship between the Henkel plot and the noise of a particulate recording medium, another property dependent on the microstructure, is also considered. The Interaction Field Factor (IFF), a single parameter characterising the non-linearity of the Henkel plot, is investigated. These results are consistent with a previous experimental study. Finally the results of the noise power spectral density for erased and saturated recording media are presented, so that characterisation of interparticle interactions may be carried out with greater accuracy.

Theoretical studies of transition metal complexes with nitriles and isocyanides

International Nuclear Information System (INIS)

Kuznetsov, Maksim L

2002-01-01

Theoretical studies of transition metal complexes with nitriles and isocyanides are reviewed. The electronic structures and the nature of coordination bonds in these complexes are discussed. The correlation between the electronic structures of transition metal complexes with nitriles and isocyanides and their structural properties, spectroscopic characteristics, and reactivities are considered. The bibliography includes 121 references.

Organizational Search Strategy: An Examination of Interdependencies, Locus and Temporality of Search

NARCIS (Netherlands)

Ebrahim, Mahdi

2017-01-01

Notwithstanding the ample research on organizational search and its performance implications, the factors that shape the organizations’ search strategy is fairly under-explored. This study investigates how problems’ characteristics influence the managerial decision of searching jointly or

Using Internet Search Engines to Obtain Medical Information: A Comparative Study

Science.gov (United States)

Wang, Liupu; Wang, Juexin; Wang, Michael; Li, Yong; Liang, Yanchun

2012-01-01

Background The Internet has become one of the most important means to obtain health and medical information. It is often the first step in checking for basic information about a disease and its treatment. The search results are often useful to general users. Various search engines such as Google, Yahoo!, Bing, and Ask.com can play an important role in obtaining medical information for both medical professionals and lay people. However, the usability and effectiveness of various search engines for medical information have not been comprehensively compared and evaluated. Objective To compare major Internet search engines in their usability of obtaining medical and health information. Methods We applied usability testing as a software engineering technique and a standard industry practice to compare the four major search engines (Google, Yahoo!, Bing, and Ask.com) in obtaining health and medical information. For this purpose, we searched the keyword breast cancer in Google, Yahoo!, Bing, and Ask.com and saved the results of the top 200 links from each search engine. We combined nonredundant links from the four search engines and gave them to volunteer users in an alphabetical order. The volunteer users evaluated the websites and scored each website from 0 to 10 (lowest to highest) based on the usefulness of the content relevant to breast cancer. A medical expert identified six well-known websites related to breast cancer in advance as standards. We also used five keywords associated with breast cancer defined in the latest release of Systematized Nomenclature of Medicine-Clinical Terms (SNOMED CT) and analyzed their occurrence in the websites. Results Each search engine provided rich information related to breast cancer in the search results. All six standard websites were among the top 30 in search results of all four search engines. Google had the best search validity (in terms of whether a website could be opened), followed by Bing, Ask.com, and Yahoo!. The search

Using Internet search engines to obtain medical information: a comparative study.

Science.gov (United States)

Wang, Liupu; Wang, Juexin; Wang, Michael; Li, Yong; Liang, Yanchun; Xu, Dong

2012-05-16

The Internet has become one of the most important means to obtain health and medical information. It is often the first step in checking for basic information about a disease and its treatment. The search results are often useful to general users. Various search engines such as Google, Yahoo!, Bing, and Ask.com can play an important role in obtaining medical information for both medical professionals and lay people. However, the usability and effectiveness of various search engines for medical information have not been comprehensively compared and evaluated. To compare major Internet search engines in their usability of obtaining medical and health information. We applied usability testing as a software engineering technique and a standard industry practice to compare the four major search engines (Google, Yahoo!, Bing, and Ask.com) in obtaining health and medical information. For this purpose, we searched the keyword breast cancer in Google, Yahoo!, Bing, and Ask.com and saved the results of the top 200 links from each search engine. We combined nonredundant links from the four search engines and gave them to volunteer users in an alphabetical order. The volunteer users evaluated the websites and scored each website from 0 to 10 (lowest to highest) based on the usefulness of the content relevant to breast cancer. A medical expert identified six well-known websites related to breast cancer in advance as standards. We also used five keywords associated with breast cancer defined in the latest release of Systematized Nomenclature of Medicine-Clinical Terms (SNOMED CT) and analyzed their occurrence in the websites. Each search engine provided rich information related to breast cancer in the search results. All six standard websites were among the top 30 in search results of all four search engines. Google had the best search validity (in terms of whether a website could be opened), followed by Bing, Ask.com, and Yahoo!. The search results highly overlapped between the

Statistical signatures of a targeted search by bacteria

Science.gov (United States)

Jashnsaz, Hossein; Anderson, Gregory G.; Pressé, Steve

2017-12-01

Chemoattractant gradients are rarely well-controlled in nature and recent attention has turned to bacterial chemotaxis toward typical bacterial food sources such as food patches or even bacterial prey. In environments with localized food sources reminiscent of a bacterium’s natural habitat, striking phenomena—such as the volcano effect or banding—have been predicted or expected to emerge from chemotactic models. However, in practice, from limited bacterial trajectory data it is difficult to distinguish targeted searches from an untargeted search strategy for food sources. Here we use a theoretical model to identify statistical signatures of a targeted search toward point food sources, such as prey. Our model is constructed on the basis that bacteria use temporal comparisons to bias their random walk, exhibit finite memory and are subject to random (Brownian) motion as well as signaling noise. The advantage with using a stochastic model-based approach is that a stochastic model may be parametrized from individual stochastic bacterial trajectories but may then be used to generate a very large number of simulated trajectories to explore average behaviors obtained from stochastic search strategies. For example, our model predicts that a bacterium’s diffusion coefficient increases as it approaches the point source and that, in the presence of multiple sources, bacteria may take substantially longer to locate their first source giving the impression of an untargeted search strategy.

Search for gluinos decaying into b-jets and transverse missing energy with the detector D0 at the Tevatron

International Nuclear Information System (INIS)

Millet, Th.

2007-05-01

The standard model of particle physics is the model of reference to explain the subatomic phenomena. This theoretical model has been successful for about 35 years. Although it has never been directly refuted, it has some theoretical and experimental limitations at high energy. That is why several new theories are trying to propose some extensions for this model. The supersymmetry is a possible extension, which is appreciated for its theoretical neatness. The work, which is presented in this manuscript, is dedicated to the search for a supersymmetric signal. The main feature of this signal are the presence of 4 b-jets and the high transverse missing energy. This search have been performed with the Run II data collected with the D0 detector from April 2003 to March 2006 (1 fb -1 ). The signature of such a topology needs a good energy resolution for the jets and a precise measure of the transverse missing energy. Consequently, it is essential to understand the information given by the calorimeter which is one of the crucial parts of the detector for such a search. The presence of the b-jets in the final state implies a efficient b-tagging. The b-tagging is a discriminant variable for the signal with respect to the standard model background. The hadronic colliders like the Tevatron are characterized by a QCD cross section which is many orders of magnitude larger than the supersymmetric signal cross section. Therefore, it is important to find fast and efficient selection cuts based on the calorimeter at the trigger level. The most important part of my work before the signal search has been dedicated on the study and the design of the trigger conditions for the jets and transverse missing energy signals. (author)

Organizational readiness for knowledge translation in chronic care: a review of theoretical components

Science.gov (United States)

2013-01-01

Background With the persistent gaps between research and practice in healthcare systems, knowledge translation (KT) has gained significance and importance. Also, in most industrialized countries, there is an increasing emphasis on managing chronic health conditions with the best available evidence. Yet, organizations aiming to improve chronic care (CC) require an adequate level of organizational readiness (OR) for KT. Objectives: The purpose of this study is to review and synthesize the existing evidence on conceptual models/frameworks of Organizational Readiness for Change (ORC) in healthcare as the basis for the development of a comprehensive framework of OR for KT in the context of CC. Data sources We conducted a systematic review of the literature on OR for KT in CC using Pubmed, Embase, CINAHL, PsychINFO, Web of Sciences (SCI and SSCI), and others. Search terms included readiness; commitment and change; preparedness; willing to change; organization and administration; and health and social services. Study selection: The search was limited to studies that had been published between the starting date of each bibliographic database (e.g., 1964 for PubMed) and November 1, 2012. Only papers that refer to a theory, a theoretical component from any framework or model on OR that were applicable to the healthcare domain were considered. We analyzed data using conceptual mapping. Data extraction: Pairs of authors independently screened the published literature by reviewing their titles and abstracts. Then, the two same reviewers appraised the full text of each study independently. Results Overall, we found and synthesized 10 theories, theoretical models and conceptual frameworks relevant to ORC in healthcare described in 38 publications. We identified five core concepts, namely organizational dynamics, change process, innovation readiness, institutional readiness, and personal readiness. We extracted 17 dimensions and 59 sub-dimensions related to these 5 concepts

The Contemporary Mass Media Education in Russia: In Search for New Theoretical Conceptions and Models

Science.gov (United States)

Fedorov, Alexander

2012-01-01

Media education in Russia in general has still not moved from the theoretical conceptions and local experiments to the wide practical implementation. It is necessary to consolidate pedagogical institutions of higher education, universities, faculties of journalism, experimenters in media education and also the media community, coordination of the…

ACADEMIC TRAINING LECTURE SERIES: Searching for Supersymmetry at the LHC

CERN Multimedia

2003-01-01

3, 4, 5, 6, 7 February 2003 ACADEMIC TRAINING LECTURE SERIES from 10.00 to 12.00 hrs - Auditorium, bldg. 500 Searching for Supersymmetry at the LHC by F. Gianotti, CERN-EP and G. Ridolfi, Univ. Di Genova, Italy We will review the general motivations for proposing non-standard descriptions of fundamental interactions. We will give a simple and pedagogical presentation of the theoretical foundations of Supersymmetry, and we will describe the main features of a realistic supersymmetric extension of the Standard Model. We will present the phenomenology expected in several motivated scenarios. We will then review the present status of the experimental searches for Supersymmetry at LEP and Tevatron, and discuss prospects at future machines with emphasis on the LHC. We will outline the search strategies and the analysis methods, and compare the sensitivity and reach of the various machines.

The generation of charge carriers in semi conductors – A theoretical study

CSIR Research Space (South Africa)

Kiarii, EM

2017-04-01

Full Text Available , vol. 678: 167-176 The generation of charge carriers in semi conductors – A theoretical study Kiarii EM Govender, Krishna K Ndungu PG Govender PG ABSTRACT: A systematic study of electronic and optical properties of titanium dioxide under...

Theoretical Expectations for the Muon's Electric Dipole Moment

CERN Document Server

Feng, J L; Shadmi, Y; Feng, Jonathan L; Matchev, Konstantin T.; Shadmi, Yael

2001-01-01

We examine the muon's electric dipole moment $\\dmu$ from a variety of theoretical perspectives. We point out that the reported deviation in the muon's g-2 can be due partially or even entirely to a new physics contribution to the muon's {\\em electric} dipole moment. In fact, the recent g-2 measurement provides the most stringent bound on $\\dmu$ to date. This ambiguity could be definitively resolved by the dedicated search for $\\dmu$ recently proposed. We then consider both model-independent and supersymmetric frameworks. Under the assumptions of scalar degeneracy, proportionality, and flavor conservation, the theoretical expectations for $\\dmu$ in supersymmetry fall just below the proposed sensitivity. However, non-degeneracy can give an order of magnitude enhancement, and lepton flavor violation can lead to $\\dmu$ of order $10^{-22}$ e cm, two orders of magnitude above the sensitivity of the $\\dmu$ experiment. We present compact expressions for leptonic dipole moments and lepton flavor violating amplitudes. ...

Search for weakly interacting massive particles with the Cryogenic Dark Matter Search experiment

Energy Technology Data Exchange (ETDEWEB)

Saab, Tarek [Stanford U.

2002-01-01

From individual galaxies, to clusters of galaxies, to in between the cushions of your sofa, Dark Matter appears to be pervasive on every scale. With increasing accuracy, recent astrophysical measurements, from a variety of experiments, are arriving at the following cosmological model : a flat cosmology (Ωk = 0) with matter and energy densities contributing roughly 1/3 and 2/3 (Ωm = 0.35, ΩΛ = 0.65). Of the matter contribution, it appears that only ~ 10% (Ωb ~ 0.04) is attributable to baryons. Astrophysical measurements constrain the remaining matter to be non-realtivistic, interacting primarily gravitationally. Various theoretical models for such Dark Matter exist. A leading candidate for the non-baryonic matter are Weakly Interacting Massive Particles (dubbed WIMPS). These particles, and their relic density may be naturally explained within the framework of Super-Symmetry theories. SuperSymmetry also offers predictions as to the scattering rates of WIMPs with baryonic matter allowing for the design and tailoring of experiments that search specifically for the WIMPs. The Cryogenic Dark Matter Search experiment is searching for evidence of WIMP interactions in crystals of Ge and Si. Using cryogenic detector technology to measure both the phonon and ionization response to a particle recoil the CDMS detectors are able to discriminate between electron and nuclear recoils, thus reducing the large rates of electron recoil backgrounds to levels with which a Dark Matter search is not only feasible, but far-reaching. This thesis will describe in some detail the physical principles behind the CDMS detector technology, highlighting the final step in the evolution of the detector design and characterization techniques. In addition, data from a 100 day long exposure of the current run at the Stanford Underground Facility will be presented, with focus given to detector performance as well as to the implications on allowable WIMP mass - cross-section parameter space.

The impact of PICO as a search strategy tool on literature search quality

DEFF Research Database (Denmark)

Eriksen, Mette Brandt; Frandsen, Tove Faber

2018-01-01

Objective: This review aimed to determine, if the use of the PICO model (Patient Intervention Comparison Outcome) as a search strategy tool affects the quality of the literature search. Methods: A comprehensive literature search was conducted in: PubMed, Embase, CINAHL, PsycInfo, Cochrane Library...... and three studies were included, data was extracted, risk of bias was assessed and a qualitative analysis was conducted. The included studies compared PICO to PIC or link to related articles in PubMed; PICOS and SPIDER. One study compared PICO to unguided searching. Due to differences in intervention...

Recent searches for superheavy elements at the superhilac

International Nuclear Information System (INIS)

Hulet, E.K.

1978-01-01

The results of the search for superheavy elements are negative with respect to the finding of such elements. However, by assuming 2 spontaneous fission events as the lower limit of detection, the limits to their formation cross sections are calculated and plotted. It is noted that the half-life limits, also shown are easily within the huge uncertainties of the theoretical predicted half lives for any superheavy element nuclides produced in the experiment. 19 references

Searching and Archiving : Exploring Online Search Behaviors of Researchers

NARCIS (Netherlands)

Vyas, Dhaval; de Groot, S.; van der Veer, Gerrit C.; Dainoff, Marvin J.

2007-01-01

Searching for relevant peer-reviewed material is an integral part of corporate and academic researchers. Researchers collect huge amount of information over the years and sometimes struggle organizing it. Based on a study with 30 academic researchers, we explore, in combination, different searching

Theoretical study on loss of coolant accident of a research reactor

International Nuclear Information System (INIS)

Lee, Kwon-Yeong; Kim, Wan-Soo

2016-01-01

Highlights: • A theoretical model of siphon breaking phenomena was developed. • A general formula using Chisholm coefficient B was proposed. • The safety requirements regarding a loss of coolant accident of research reactors could be found out. - Abstract: Under the design conditions of a research reactor, the siphon phenomenon induced by pipe rupture can cause continuous efflux of water. In order to prevent water efflux, an additional facility is necessary. A siphon breaker is a type of safety facility that can resist the loss of coolant effectively. However, analysis of siphon breaking is complex since it comprises two-phase flow and there are many inputs to be considered. For this reason, we analyzed the experimental results to develop a theoretical model of siphon breaking phenomena. Developed model is based on fluid mechanics and Chisholm model. From Bernoulli’s equation, the velocity and quantity as well as undershooting height, water level, pressure, friction coefficient, and factors related to the two-phase flow could be calculated. The Chisholm model, which is able to analyze the two-phase flow, can predict the results in a manner similar to those obtained from a real-scale experiment, and a general formula using Chisholm coefficient B was proposed in this study. Also, we verified the theoretical model and concluded that it is possible to analyze the siphon breaking. Moreover, the design conditions that can satisfy the safety requirements regarding a loss of coolant accident of research reactors could be found out by using the theoretical model. In conclusion, we propose the theoretical model which can analyze the siphon breaking as real, and it is helpful not only to analyze but also to design the siphon breaker.

A comparison of results of empirical studies of supplementary search techniques and recommendations in review methodology handbooks: a methodological review.

Science.gov (United States)

Cooper, Chris; Booth, Andrew; Britten, Nicky; Garside, Ruth

2017-11-28

The purpose and contribution of supplementary search methods in systematic reviews is increasingly acknowledged. Numerous studies have demonstrated their potential in identifying studies or study data that would have been missed by bibliographic database searching alone. What is less certain is how supplementary search methods actually work, how they are applied, and the consequent advantages, disadvantages and resource implications of each search method. The aim of this study is to compare current practice in using supplementary search methods with methodological guidance. Four methodological handbooks in informing systematic review practice in the UK were read and audited to establish current methodological guidance. Studies evaluating the use of supplementary search methods were identified by searching five bibliographic databases. Studies were included if they (1) reported practical application of a supplementary search method (descriptive) or (2) examined the utility of a supplementary search method (analytical) or (3) identified/explored factors that impact on the utility of a supplementary method, when applied in practice. Thirty-five studies were included in this review in addition to the four methodological handbooks. Studies were published between 1989 and 2016, and dates of publication of the handbooks ranged from 1994 to 2014. Five supplementary search methods were reviewed: contacting study authors, citation chasing, handsearching, searching trial registers and web searching. There is reasonable consistency between recommended best practice (handbooks) and current practice (methodological studies) as it relates to the application of supplementary search methods. The methodological studies provide useful information on the effectiveness of the supplementary search methods, often seeking to evaluate aspects of the method to improve effectiveness or efficiency. In this way, the studies advance the understanding of the supplementary search methods. Further

THEORETICAL AND EXPERIMENTAL STUDY OF STRUCTURES SUBJECTED TO EARTHQUAKES

Energy Technology Data Exchange (ETDEWEB)

Soubirou, A.

1967-12-31

The object of the study was the investigation of the behaviour of structures subject to earthquakes. After .describing and analysing seismic movements, useful concepts for earthquake-proofing structures are lintroduced. Then, the dynamic behaviour of systems with n degrees of freedom was studied in order to evolve the theoretical computation of seismic behaviour, a typical application being reticulated structures. The next stage was showing the computational procedure for seismic spectra and the natural frequencies of buildings, an attempt being made to define earthquake-proofing criteria for a special type of reinforced-concrete construction. . The last matter dealt with is elastoplastic behaviour of structures, a study of increasingly growing importance.

High activity and Levy searches: jellyfish can search the water column like fish.

Science.gov (United States)

Hays, Graeme C; Bastian, Thomas; Doyle, Thomas K; Fossette, Sabrina; Gleiss, Adrian C; Gravenor, Michael B; Hobson, Victoria J; Humphries, Nicolas E; Lilley, Martin K S; Pade, Nicolas G; Sims, David W

2012-02-07

Over-fishing may lead to a decrease in fish abundance and a proliferation of jellyfish. Active movements and prey search might be thought to provide a competitive advantage for fish, but here we use data-loggers to show that the frequently occurring coastal jellyfish (Rhizostoma octopus) does not simply passively drift to encounter prey. Jellyfish (327 days of data from 25 jellyfish with depth collected every 1 min) showed very dynamic vertical movements, with their integrated vertical movement averaging 619.2 m d(-1), more than 60 times the water depth where they were tagged. The majority of movement patterns were best approximated by exponential models describing normal random walks. However, jellyfish also showed switching behaviour from exponential patterns to patterns best fitted by a truncated Lévy distribution with exponents (mean μ=1.96, range 1.2-2.9) close to the theoretical optimum for searching for sparse prey (μopt≈2.0). Complex movements in these 'simple' animals may help jellyfish to compete effectively with fish for plankton prey, which may enhance their ability to increase in dominance in perturbed ocean systems.

A theoretical study on interaction of proline with gold cluster

Indian Academy of Sciences (India)

with Au3 (Pakiari and Jamshidi 2007) and interaction of. ∗. Author for correspondence (harjinder.singh@iiit.ac.in) small gold clusters with xDNA base pairs (Sharma et al. 2009) have motivated us to carry out a theoretical study on interaction of proline with gold nanoparticles. Proline is unique among the natural amino acids ...

Box-Cox Test: the theoretical justification and US-China empirical study

Directory of Open Access Journals (Sweden)

Tam Bang Vu

2011-01-01

Full Text Available In econometrics, the derivation of a theoretical model leads sometimes to two econometric models, which can be considered justified based on their respective approximation approaches. Hence, the decision of choosing one between the two hinges on applied econometric tools. In this paper, the authors develop a theoretical econometrics consumer maximization model to measure the flow of durables’ expenditures where depreciation is added to former classical econometrics model. The proposed model was formulated in both linear and logarithmic forms. Box-Cox tests were used to choose the most appropriate one among them. The proposed model was then applied to the historical data from the U.S. and China for a comparative study and the results discussed.

Theoretical Foundations of Study of Cartography

Science.gov (United States)

Talhofer, Václav; Hošková-Mayerová, Šárka

2018-05-01

Cartography and geoinformatics are technical-based fields which deal with modelling and visualization of landscape in the form of a map. The theoretical foundation is necessary to obtain during study of cartography and geoinformatics based mainly on mathematics. For the given subjects, mathematics is necessary for understanding of many procedures that are connected to modelling of the Earth as a celestial body, to ways of its projection into a plane, to methods and procedures of modelling of landscape and phenomena in society and visualization of these models in the form of electronic as well as classic paper maps. Not only general mathematics, but also its extension of differential geometry of curves and surfaces, ways of approximation of lines and surfaces of functional surfaces, mathematical statistics and multi-criterial analyses seem to be suitable and necessary. Underestimation of the significance of mathematical education in cartography and geoinformatics is inappropriate and lowers competence of cartographers and professionals in geographic information science and technology to solve problems.

Search strings for the study of putative occupational determinants of disease

Science.gov (United States)

Mattioli, Stefano; Zanardi, Francesca; Baldasseroni, Alberto; Schaafsma, Frederieke; Cooke, Robin MT; Mancini, Gianpiero; Fierro, Mauro; Santangelo, Chiara; Farioli, Andrea; Fucksia, Serenella; Curti, Stefania; Verbeek, Jos

2010-01-01

Objective To identify efficient PubMed search strategies to retrieve articles regarding putative occupational determinants of conditions not generally considered to be work related. Methods Based on MeSH definitions and expert knowledge, we selected as candidate search terms the four MeSH terms describing ‘occupational disease’, ‘occupational exposure’, ‘occupational health’ and ‘occupational medicine’ (DEHM) alongside 22 other promising terms. We first explored overlaps between the candidate terms in PubMed. Using random samples of abstracts retrieved by each term, we estimated the proportions of articles containing potentially pertinent information regarding occupational aetiology in order to formulate two search strategies (one more ‘specific’, one more ‘sensitive’). We applied these strategies to retrieve information on the possible occupational aetiology of meningioma, pancreatitis and atrial fibrillation. Results Only 20.3% of abstracts were retrieved by more than one DEHM term. The more ‘specific’ search string was based on the combination of terms that yielded the highest proportion (40%) of potentially pertinent abstracts. The more ‘sensitive’ string was based on the use of broader search fields and additional coverage provided by other search terms under study. Using the specific string, the numbers of abstracts needed to read to find one potentially pertinent article were 1.2 for meningioma, 1.9 for pancreatitis and 1.8 for atrial fibrillation. Using the sensitive strategy, the numbers needed to read were 4.4 for meningioma, 8.9 for pancreatitis and 10.5 for atrial fibrillation. Conclusions The proposed strings could help health care professionals explore putative occupational aetiology for diseases that are not generally thought to be work related. PMID:19819858

Online Information Search Performance and Search Strategies in a Health Problem-Solving Scenario.

Science.gov (United States)

Sharit, Joseph; Taha, Jessica; Berkowsky, Ronald W; Profita, Halley; Czaja, Sara J

2015-01-01

Although access to Internet health information can be beneficial, solving complex health-related problems online is challenging for many individuals. In this study, we investigated the performance of a sample of 60 adults ages 18 to 85 years in using the Internet to resolve a relatively complex health information problem. The impact of age, Internet experience, and cognitive abilities on measures of search time, amount of search, and search accuracy was examined, and a model of Internet information seeking was developed to guide the characterization of participants' search strategies. Internet experience was found to have no impact on performance measures. Older participants exhibited longer search times and lower amounts of search but similar search accuracy performance as their younger counterparts. Overall, greater search accuracy was related to an increased amount of search but not to increased search duration and was primarily attributable to higher cognitive abilities, such as processing speed, reasoning ability, and executive function. There was a tendency for those who were younger, had greater Internet experience, and had higher cognitive abilities to use a bottom-up (i.e., analytic) search strategy, although use of a top-down (i.e., browsing) strategy was not necessarily unsuccessful. Implications of the findings for future studies and design interventions are discussed.

Studies In Theoretical High Energy Particle Physics

Energy Technology Data Exchange (ETDEWEB)

Keung, Wai Yee [Univ. of Illinois, Chicago, IL (United States)

2017-07-01

This is a final technical report for grant no. DE-SC0007948 describing research activities in theoretical high energy physics at University of Illinois at Chicago for the whole grant period from July 1, 2012 to March 31, 2017.

Reading and visual search: a developmental study in normal children.

Directory of Open Access Journals (Sweden)

Magali Seassau

Full Text Available Studies dealing with developmental aspects of binocular eye movement behaviour during reading are scarce. In this study we have explored binocular strategies during reading and during visual search tasks in a large population of normal young readers. Binocular eye movements were recorded using an infrared video-oculography system in sixty-nine children (aged 6 to 15 and in a group of 10 adults (aged 24 to 39. The main findings are (i in both tasks the number of progressive saccades (to the right and regressive saccades (to the left decreases with age; (ii the amplitude of progressive saccades increases with age in the reading task only; (iii in both tasks, the duration of fixations as well as the total duration of the task decreases with age; (iv in both tasks, the amplitude of disconjugacy recorded during and after the saccades decreases with age; (v children are significantly more accurate in reading than in visual search after 10 years of age. Data reported here confirms and expands previous studies on children's reading. The new finding is that younger children show poorer coordination than adults, both while reading and while performing a visual search task. Both reading skills and binocular saccades coordination improve with age and children reach a similar level to adults after the age of 10. This finding is most likely related to the fact that learning mechanisms responsible for saccade yoking develop during childhood until adolescence.

Experimental and theoretical studies of manganite and magnetite compounds

International Nuclear Information System (INIS)

Srinitiwarawong, Chatchai

2002-01-01

In the recent years interest in the transition oxide compounds has renewed among researchers in the field of condensed matter physics. This thesis presents the studies of the two families of the transition oxides, the manganite and magnetite compounds. Manganite has regained the interest since the discovery of the large magnetoresistance around its Curie temperature in 1990s. Magnetite on the other hand is the oldest magnetic material known to man however some of its physical properties are still controversial. The experimental works address some basic properties of these compounds when fabricated in the form of thin films. These include the resistivity measurements and magnetic measurements as well as the Hall effect. The various models of transport mechanism have been compared. The magnetic field and the temperature dependence of magnetoresistance have also been studied. Simple devices such as an artificial grain boundary and bilayers thin film have been investigated. The second part of this thesis concentrates on the theoretical aspects of the fundamental physics behind these two compounds. The problem of electrons tunnelling between the magnetite electrodes has been addressed taking into account the surface effect with distortion. The last chapter presents a theoretical study of the spinless-Hubbard model which is the simplest approximation of the conduction electrons in magnetite and manganite. The results are obtained from the Hartree-Fock and the Hubbard-I approximations as well as the exact diagonalisation method. (author)

Reduced and oxidised scytonemin: theoretical protocol for Raman spectroscopic identification of potential key biomolecules for astrobiology.

Science.gov (United States)

Varnali, Tereza; Edwards, Howell G M

2014-01-03

Scytonemin is an important UV-radiation protective biomolecule synthesised by extremophilic cyanobacteria in stressed terrestrial environments. Scytonemin and its reduced form have been both isolated experimentally and the Raman spectrum for scytonemin has been assigned and characterised experimentally both in extracts and in living extremophilic cyanobacterial colonies. Scytonemin is recognised as a key biomarker molecule for terrestrial organisms in stressed environments. We propose a new, theoretically plausible structure for oxidised scytonemin which has not been mentioned in the literature hitherto. DFT calculations for scytonemin, reduced scytonemin and the new structure modelled and proposed for oxidised scytonemin are reported along with their Raman spectroscopic data and λmax UV-absorption data obtained theoretically. Comparison of the vibrational spectroscopic assignments allows the three forms of scytonemin to be detected and identified and assist not only in the clarification of the major features in the experimentally observed Raman spectral data for the parent scytonemin but also support a protocol proposed for their analytical discrimination. The results of this study provide a basis for the search for molecules of this type in future astrobiological missions of exploration and the search for extinct and extant life terrestrially. Copyright © 2013 Elsevier B.V. All rights reserved.

Natural Language Search Interfaces: Health Data Needs Single-Field Variable Search.

Science.gov (United States)

Jay, Caroline; Harper, Simon; Dunlop, Ian; Smith, Sam; Sufi, Shoaib; Goble, Carole; Buchan, Iain

2016-01-14

Data discovery, particularly the discovery of key variables and their inter-relationships, is key to secondary data analysis, and in-turn, the evolving field of data science. Interface designers have presumed that their users are domain experts, and so they have provided complex interfaces to support these "experts." Such interfaces hark back to a time when searches needed to be accurate first time as there was a high computational cost associated with each search. Our work is part of a governmental research initiative between the medical and social research funding bodies to improve the use of social data in medical research. The cross-disciplinary nature of data science can make no assumptions regarding the domain expertise of a particular scientist, whose interests may intersect multiple domains. Here we consider the common requirement for scientists to seek archived data for secondary analysis. This has more in common with search needs of the "Google generation" than with their single-domain, single-tool forebears. Our study compares a Google-like interface with traditional ways of searching for noncomplex health data in a data archive. Two user interfaces are evaluated for the same set of tasks in extracting data from surveys stored in the UK Data Archive (UKDA). One interface, Web search, is "Google-like," enabling users to browse, search for, and view metadata about study variables, whereas the other, traditional search, has standard multioption user interface. Using a comprehensive set of tasks with 20 volunteers, we found that the Web search interface met data discovery needs and expectations better than the traditional search. A task × interface repeated measures analysis showed a main effect indicating that answers found through the Web search interface were more likely to be correct (F1,19=37.3, Pnatural language search interfaces for variable search supporting in particular: query reformulation; data browsing; faceted search; surrogates; relevance

A Comparative Study of Theoretical Graph Models for Characterizing Structural Networks of Human Brain

Directory of Open Access Journals (Sweden)

Xiaojin Li

2013-01-01

Full Text Available Previous studies have investigated both structural and functional brain networks via graph-theoretical methods. However, there is an important issue that has not been adequately discussed before: what is the optimal theoretical graph model for describing the structural networks of human brain? In this paper, we perform a comparative study to address this problem. Firstly, large-scale cortical regions of interest (ROIs are localized by recently developed and validated brain reference system named Dense Individualized Common Connectivity-based Cortical Landmarks (DICCCOL to address the limitations in the identification of the brain network ROIs in previous studies. Then, we construct structural brain networks based on diffusion tensor imaging (DTI data. Afterwards, the global and local graph properties of the constructed structural brain networks are measured using the state-of-the-art graph analysis algorithms and tools and are further compared with seven popular theoretical graph models. In addition, we compare the topological properties between two graph models, namely, stickiness-index-based model (STICKY and scale-free gene duplication model (SF-GD, that have higher similarity with the real structural brain networks in terms of global and local graph properties. Our experimental results suggest that among the seven theoretical graph models compared in this study, STICKY and SF-GD models have better performances in characterizing the structural human brain network.

Academic Training Lecture: Higgs Boson Searches at Hadron Colliders

CERN Multimedia

HR Department

2010-01-01

Regular Programme 21, 22, 23 & 24 June 2010 from 11:00 to 12:00 - Main Auditorium, Bldg. 500-1-001 Higgs Boson Searches at Hadron Colliders by Dr. Karl Jakobs (University of Freiburg) In these Academic Training lectures, the phenomenology of Higgs bosons and search strategies at hadron colliders are discussed. After a brief introduction on Higgs bosons in the Standard Model and a discussion of present direct and indirect constraints on its mass the status of the theoretical cross section calculations for Higgs boson production at hadron colliders is reviewed. In the following lectures important experimental issues relevant for Higgs boson searches (trigger, measurements of leptons, jets and missing transverse energy) are presented. This is followed by a detailed discussion of the discovery potential for the Standard Model Higgs boson for both the Tevatron and the LHC experiments. In addition, various scenarios beyond the Standard Model, primarily the MSSM, are considered. Finally, the potential and ...

Theoretical and experimental study of thermoacoustic engines

Science.gov (United States)

Raspet, Richard; Bass, Henry E.; Arnott, W. P.

1992-12-01

A three year study of thermoacoustic engines operating as prime movers and refrigerators was completed. The major thrust of this effort was the use and theoretical description of ceramic honeycomb structures as the active element in thermoacoustic engines. An air-filled demonstration prime mover was constructed and demonstrated at Acoustical Society of America and IEE meetings. A helium-filled test prime mover was designed and built an is being employed in studies of the threshold of oscillation as a function of temperature difference and pressure. In addition, acoustically based theories of the thermoacoustic engine have been developed and tested for a parallel plate stack at the Naval Postgraduate School and for a honeycomb stack at the University of Mississippi. Most of this work is described in detail in the attached publications. In this report we will give an overview of the research completed to date and its relationship to work performed at the Naval Postgraduate School and to future work at the University of Mississippi.

The CHASE laboratory search for chameleon dark energy

International Nuclear Information System (INIS)

Steffen, Jason H.

2010-01-01

A scalar field is a favorite candidate for the particle responsible for dark energy. However, few theoretical means exist that can simultaneously explain the observed acceleration of the Universe and evade tests of gravity. The chameleon mechanism, whereby the properties of a particle depend upon the local environment, is one possible avenue. We present the results of the Chameleon Afterglow Search (CHASE) experiment, a laboratory probe for chameleon dark energy. CHASE marks a significant improvement other searches for chameleons both in terms of its sensitivity to the photon/chameleon coupling as well as its sensitivity to the classes of chameleon dark energy models and standard power-law models. Since chameleon dark energy is virtually indistinguishable from a cosmological constant, CHASE tests dark energy models in a manner not accessible to astronomical surveys.

The CHASE laboratory search for chameleon dark energy

Energy Technology Data Exchange (ETDEWEB)

Steffen, Jason [Fermi National Accelerator Laboratory - Fermilab, P.O. Box 500, Batavia, IL 60510-5011 (United States)

2010-07-01

A scalar field is a favorite candidate for the particle responsible for dark energy. However, few theoretical means exist that can simultaneously explain the observed acceleration of the Universe and evade tests of gravity. The chameleon mechanism, whereby the properties of a particle depend upon the local environment, is one possible avenue. I present the results of the Chameleon Afterglow Search (CHASE) experiment, a laboratory probe for chameleon dark energy. CHASE marks a significant improvement over other searches for chameleons both in terms of its sensitivity to the photon/chameleon coupling as well as its sensitivity to the classes of chameleon dark energy models and standard power-law models. Since chameleon dark energy is virtually indistinguishable from a cosmological constant, CHASE tests dark energy models in a manner not accessible to astronomical surveys. (author)

Research in theoretical physics: Annual progress report for period April 1, 1988--March 31, 1989

International Nuclear Information System (INIS)

Domokos, G.; Kovesi-Domokos, S.

1988-11-01

This report contains a summary of research carried out in order to search for a substructure of quarks and leptons. Theoretical predictions valid for a large class of composite models suggest enhanced muon production in high energy lepton-induced reactions. A tentative analysis of some cosmic ray data indicates that the predictions of such models are in accordance with the data. In order to move towards the construction of satisfactory composite models, a study of gauge invariant effective actions and phase transitions in gauge theories was begun. 20 refs., 1 fig

Usability Testing of a Large, Multidisciplinary Library Database: Basic Search and Visual Search

Directory of Open Access Journals (Sweden)

Jody Condit Fagan

2006-09-01

Full Text Available Visual search interfaces have been shown by researchers to assist users with information search and retrieval. Recently, several major library vendors have added visual search interfaces or functions to their products. For public service librarians, perhaps the most critical area of interest is the extent to which visual search interfaces and text-based search interfaces support research. This study presents the results of eight full-scale usability tests of both the EBSCOhost Basic Search and Visual Search in the context of a large liberal arts university.

Beyond MEDLINE for literature searches.

Science.gov (United States)

Conn, Vicki S; Isaramalai, Sang-arun; Rath, Sabyasachi; Jantarakupt, Peeranuch; Wadhawan, Rohini; Dash, Yashodhara

2003-01-01

To describe strategies for a comprehensive literature search. MEDLINE searches result in limited numbers of studies that are often biased toward statistically significant findings. Diversified search strategies are needed. Empirical evidence about the recall and precision of diverse search strategies is presented. Challenges and strengths of each search strategy are identified. Search strategies vary in recall and precision. Often sensitivity and specificity are inversely related. Valuable search strategies include examination of multiple diverse computerized databases, ancestry searches, citation index searches, examination of research registries, journal hand searching, contact with the "invisible college," examination of abstracts, Internet searches, and contact with sources of synthesized information. Extending searches beyond MEDLINE enables researchers to conduct more systematic comprehensive searches.

Visual search behaviour in skeletal radiographs: a cross-speciality study

International Nuclear Information System (INIS)

Leong, J.J.H.; Nicolaou, M.; Emery, R.J.; Darzi, A.W.; Yang, G.-Z.

2007-01-01

Aim: To determine whether experience improves the consistency of visual search behaviour in fracture identification in plain radiographs, and the effect of specialization. Material and methods: Twenty-five observers consisting of consultant radiologists, consultant orthopaedic surgeons, orthopaedic specialist registrars, orthopaedic senior house officers, and accident and emergency senior house officers examined 33 skeletal radiographs (shoulder, hand, and knee). Eye movement data were collected using a Tobii 1750 eye tracker with levels of diagnostic confidence collected simultaneously. Kullback-Leibler (KL) divergence and Gaussian mixture model fitting of fixation distance-to-fracture were used to calculate the consistency and the relationship between discovery and reflective visual search phases among different observer groups. Results: Total time spent studying the radiograph was not significantly different between the groups. However, the expert groups had a higher number of true positives (p < 0.001) with less dwell time on the fracture site (p < 0.001) and smaller KL distance (r = 0.062, p < 0.001) between trials. The Gaussian mixture model revealed smaller mean squared error in the expert groups in hand radiographs (r 0.162, p = 0.07); however, the reverse was true in shoulder radiographs (r -0.287, p < 0.001). The relative duration of the reflective phase decreases as the confidence level increased (r = 0.266, p = 0.074). Conclusions: Expert search behaviour exhibited higher accuracy and consistency whilst using less time fixating on fracture sites. This strategy conforms to the discovery and reflective phases of the global-focal model, where the reflective search may be implicated in the cross-referencing and conspicuity of the target, as well as the level of decision-making process involved. The effect of specialization appears to change the search strategy more than the effect of the length of training

Skewed Binary Search Trees

DEFF Research Database (Denmark)

Brodal, Gerth Stølting; Moruz, Gabriel

2006-01-01

It is well-known that to minimize the number of comparisons a binary search tree should be perfectly balanced. Previous work has shown that a dominating factor over the running time for a search is the number of cache faults performed, and that an appropriate memory layout of a binary search tree...... can reduce the number of cache faults by several hundred percent. Motivated by the fact that during a search branching to the left or right at a node does not necessarily have the same cost, e.g. because of branch prediction schemes, we in this paper study the class of skewed binary search trees....... For all nodes in a skewed binary search tree the ratio between the size of the left subtree and the size of the tree is a fixed constant (a ratio of 1/2 gives perfect balanced trees). In this paper we present an experimental study of various memory layouts of static skewed binary search trees, where each...

Higgs Boson Properties and Search for Additional Resonances

CERN Document Server

AUTHOR|(INSPIRE)INSPIRE-00435709

The Higgs boson was predicted by the Standard Model of particle physics and jointly discovered by the CMS and ATLAS experiments at LHC, in 2012. Following its discovery, the property measurements of the Higgs boson and the search for additional resonances become important research goals. The Standard Model is not the complete theory and leaves many questions unanswered, therefore it is important to search for any evidence of new physics beyond the SM. This thesis will briefly introduce the theoretical motivation for the Higgs boson, the production and decay mechanisms of the Higgs boson, and the methods used for analysis of the Higgs boson properties. The spin-1 and spin-2 Higgs hypotheses are tested in H->ZZ->4l channel, using the data recorded by CMS in Run1 of LHC. The exotic spin models were excluded and the Higgs boson is shown to agree with the Standard Model prediction of spin-0. The search for high-mass Higgs-like resonance is performed in H->ZZ->4l and H->ZZ->2l2q channels, using data recorded by CMS...

Locating qualitative studies in dementia on MEDLINE, EMBASE, CINAHL, and PsycINFO: A comparison of search strategies.

Science.gov (United States)

Rogers, Morwenna; Bethel, Alison; Abbott, Rebecca

2017-10-28

Qualitative research in dementia improves understanding of the experience of people affected by dementia. Searching databases for qualitative studies is problematic. Qualitative-specific search strategies might help with locating studies. To examine the effectiveness (sensitivity and precision) of 5 qualitative strategies on locating qualitative research studies in dementia in 4 major databases (MEDLINE, EMBASE, PsycINFO, and CINAHL). Qualitative dementia studies were checked for inclusion on MEDLINE, EMBASE, PsycINFO, and CINAHL. Five qualitative search strategies (subject headings, simple free-text terms, complex free-text terms, and 2 broad-based strategies) were tested for study retrieval. Specificity, precision and number needed to read were calculated. Two hundred fourteen qualitative studies in dementia were included. PsycINFO and CINAHL held the most qualitative studies out the 4 databases studied (N = 171 and 166, respectively) and both held unique records (N = 14 and 7, respectively). The controlled vocabulary strategy in CINAHL returned 96% (N = 192) of studies held; by contrast, controlled vocabulary in PsycINFO returned 7% (N = 13) of studies held. The broad-based strategies returned more studies (93-99%) than the other free-text strategies (22-82%). Precision ranged from 0.061 to 0.004 resulting in a number needed to read to obtain 1 relevant study ranging from 16 (simple free-text search in CINAHL) to 239 (broad-based search in EMBASE). Qualitative search strategies using 3 broad terms were more sensitive than long complex searches. The controlled vocabulary for qualitative research in CINAHL was particularly effective. Furthermore, results indicate that MEDLINE and EMBASE offer little benefit for locating qualitative dementia research if CINAHL and PSYCINFO are also searched. Copyright © 2017 John Wiley & Sons, Ltd.

Model unspecific search in CMS. First results at 13 TeV

Energy Technology Data Exchange (ETDEWEB)

Roemer, Jonas; Albert, Andreas; Duchardt, Deborah; Hebbeker, Thomas; Knutzen, Simon; Lieb, Jonas; Meyer, Arnd; Pook, Tobias [III. Physikalisches Institut A, RWTH Aachen University (Germany)

2016-07-01

Following an upgrade in center of mass energy from √(s) = 8 TeV to 13 TeV, the LHC delivered first proton-proton collisions at this unprecedented energy in 2015. The CMS experiment recorded data corresponding to an integrated luminosity of 3.7 fb{sup -1}. Since many theoretical models predict signal cross sections to increase strongly with the center of mass energy, the data taken at √(s) = 13 TeV are competitive to the previous data taking period even with a lower recorded integrated luminosity. The Model Unspecific Search in CMS (MUSiC) searches for physics beyond the standard model independent of theoretical models. Using an automatic method, kinematic distributions of the data are compared with the standard model expectation in every final state. Therefore, MUSiC reduces the chance of overlooking new physics, since even distributions not covered by dedicated analyses are investigated. This talk outlines changes to the analysis made necessary by the increased center of mass energy and first results with lepton triggered events.

Electronic properties of diphenyl-s-tetrazine and some related oligomers. An spectroscopic and theoretical study

Science.gov (United States)

Moral, Mónica; García, Gregorio; Peñas, Antonio; Garzón, Andrés; Granadino-Roldán, José M.; Melguizo, Manuel; Fernández-Gómez, Manuel

2012-10-01

This work presents a theoretical and spectroscopic study on the electronic and structural properties of the diphenyl-s-tetrazine molecule (Ph2Tz) and some oligomeric derivatives. Ph2Tz was synthesized through a variation of Pinner-type reaction which uses N-acetylcysteine as catalyst. Insight into the structure and electronic properties of the title compound was obtained through IR, Raman, UV-Vis spectra in different solvents, and theoretical calculations. Theoretical studies have been extended to different n-mers derivatives up to an ideal molecular wire through the oligomeric approximation, predicting this way electronic properties such as LUMO energy levels, electron affinity and reorganization energy in order to assess their possible applications in molecular electronics.

EFFICIENCY OF ISO 9001 IN PORTUGAL: A QUALITATIVE STUDY FROM A HOLISTIC THEORETICAL PERSPECTIVE

Directory of Open Access Journals (Sweden)

Alcina Dias

2013-03-01

Full Text Available The purpose of this paper is to analy se the efficiency of ISO 9001 from a holistic theoretical approach where the Contingency theory, the Institutional theory and the Resources-Based View are integrated. The study was carried out in companies of different sectors of activity in Portugal, based on a qualitative methodology (interviews. The fact of the interviews having been undertaken under an ISO 9001 structure made it easier for companies to grasp the issues under investigation. An ISO 9001 characterisation was carried out on a theoretical framework approach and findings point out efficiency gains and revealed that the absence of ISO 9001 would work as a competitive disadvantage. The contribution of this research aims to reinforce the state of art as concerns the theoretical scope of analysis of these issues enriched by the case study achievement.

SEARCH FOR NEW PHYSICS AT A SUPER-B FACTORY.

Energy Technology Data Exchange (ETDEWEB)

BROWDER,T.E.; SONI,A.

2004-01-05

The importance of a Super-B Factory in the search for New Physics, in particular, due to CP-od phase(s) from physics beyond the Standard Model is surveyed. The first point to emphasize is that we know now how to directly measure all three angles of the unitarity triangle very cleanly, i. e. without theoretical assumptions with irreducible theory error {le} 1%; however this requires much more luminosity than is currently available at B-factories. Direct searches via penguin-dominated hadronic modes as well as radiative, pair-leptonic and semi-leptonic decays are also discussed. Null tests of the SM are stressed as these will play a crucial role especially if the effects of BSM phase(s) on B-physics are small.

Organizational readiness for knowledge translation in chronic care: a review of theoretical components.

Science.gov (United States)

Attieh, Randa; Gagnon, Marie-Pierre; Estabrooks, Carole A; Légaré, France; Ouimet, Mathieu; Roch, Geneviève; Ghandour, El Kebir; Grimshaw, Jeremy

2013-11-28

With the persistent gaps between research and practice in healthcare systems, knowledge translation (KT) has gained significance and importance. Also, in most industrialized countries, there is an increasing emphasis on managing chronic health conditions with the best available evidence. Yet, organizations aiming to improve chronic care (CC) require an adequate level of organizational readiness (OR) for KT. The purpose of this study is to review and synthesize the existing evidence on conceptual models/frameworks of Organizational Readiness for Change (ORC) in healthcare as the basis for the development of a comprehensive framework of OR for KT in the context of CC. We conducted a systematic review of the literature on OR for KT in CC using Pubmed, Embase, CINAHL, PsychINFO, Web of Sciences (SCI and SSCI), and others. Search terms included readiness; commitment and change; preparedness; willing to change; organization and administration; and health and social services. The search was limited to studies that had been published between the starting date of each bibliographic database (e.g., 1964 for PubMed) and November 1, 2012. Only papers that refer to a theory, a theoretical component from any framework or model on OR that were applicable to the healthcare domain were considered. We analyzed data using conceptual mapping. Pairs of authors independently screened the published literature by reviewing their titles and abstracts. Then, the two same reviewers appraised the full text of each study independently. Overall, we found and synthesized 10 theories, theoretical models and conceptual frameworks relevant to ORC in healthcare described in 38 publications. We identified five core concepts, namely organizational dynamics, change process, innovation readiness, institutional readiness, and personal readiness. We extracted 17 dimensions and 59 sub-dimensions related to these 5 concepts. Our findings provide a useful overview for researchers interested in ORC and aims

[How do authors of systematic reviews restrict their literature searches when only studies from Germany should be included?

Science.gov (United States)

Pieper, Dawid; Mathes, Tim; Palm, Rebecca; Hoffmann, Falk

2016-11-01

The use of search filters (e. g. for study types) facilitates the process of literature searching. Regional limits might be helpful depending on the research question. Regional search filters are already available for some regions, but not for Germany. Our aim is to give an overview of applied search strategies in systematic reviews (SRs) focusing on Germany. We searched Medline (via Pubmed) applying a focused search strategy to identify SRs focusing on Germany in January 2016. Study selection and data extraction were performed by two reviewers independently. The search strategies with a focus on Germany were analyzed in terms of reasonableness and completeness relying on the Peer Review of Electronic Search Strategies (PRESS) criteria. A narrative evidence synthesis was performed. In total, 36 SRs (13 written in English) were included. 78% were published in 2012 or later. The majority (89%) of SRs utilized at least two different sources for their search with databases and checking references being the most common. 17 SRs did not use any truncations, ten SRs did not restrict their search to Germany, six SRs reported to have searched for German OR Germany. Only ten articles searched for the term Germany (occasionally jointly with the term Deutschland) without any use of an adjective such as German. There is a high interest in regionally focused SRs. The identified search strategies revealed a need for improvement. It would be helpful to develop a regional search filter for Germany that is able to identify studies performed in Germany. Copyright © 2016. Published by Elsevier GmbH.

Joint Experimental and Theoretical Study on Vibrational Excitation Cross Sections for Electron Collisions with Diacetylene

Czech Academy of Sciences Publication Activity Database

Čurík, Roman; Paidarová, Ivana; Allan, M.; Čársky, Petr

2014-01-01

Roč. 118, č. 41 (2014), s. 9734-9744 ISSN 1089-5639 R&D Projects: GA ČR GAP208/11/0452; GA MŠk LD14088 Institutional support: RVO:61388955 Keywords : diacetylenes * electron collision * theoretical study Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.693, year: 2014

Natural Language Search Interfaces: Health Data Needs Single-Field Variable Search

Science.gov (United States)

Smith, Sam; Sufi, Shoaib; Goble, Carole; Buchan, Iain

2016-01-01

Background Data discovery, particularly the discovery of key variables and their inter-relationships, is key to secondary data analysis, and in-turn, the evolving field of data science. Interface designers have presumed that their users are domain experts, and so they have provided complex interfaces to support these “experts.” Such interfaces hark back to a time when searches needed to be accurate first time as there was a high computational cost associated with each search. Our work is part of a governmental research initiative between the medical and social research funding bodies to improve the use of social data in medical research. Objective The cross-disciplinary nature of data science can make no assumptions regarding the domain expertise of a particular scientist, whose interests may intersect multiple domains. Here we consider the common requirement for scientists to seek archived data for secondary analysis. This has more in common with search needs of the “Google generation” than with their single-domain, single-tool forebears. Our study compares a Google-like interface with traditional ways of searching for noncomplex health data in a data archive. Methods Two user interfaces are evaluated for the same set of tasks in extracting data from surveys stored in the UK Data Archive (UKDA). One interface, Web search, is “Google-like,” enabling users to browse, search for, and view metadata about study variables, whereas the other, traditional search, has standard multioption user interface. Results Using a comprehensive set of tasks with 20 volunteers, we found that the Web search interface met data discovery needs and expectations better than the traditional search. A task × interface repeated measures analysis showed a main effect indicating that answers found through the Web search interface were more likely to be correct (F 1,19=37.3, Peffect of task (F 3,57=6.3, Pinterface (F 1,19=18.0, Peffect of task (F 2,38=4.1, P=.025, Greenhouse

Grey Literature Searching for Health Sciences Systematic Reviews: A Prospective Study of Time Spent and Resources Utilized.

Science.gov (United States)

Saleh, Ahlam A; Ratajeski, Melissa A; Bertolet, Marnie

To identify estimates of time taken to search grey literature in support of health sciences systematic reviews and to identify searcher or systematic review characteristics that may impact resource selection or time spent searching. A survey was electronically distributed to searchers embarking on a new systematic review. Characteristics of the searcher and systematic review were collected along with time spent searching and what resources were searched. Time and resources were tabulated and resources were categorized as grey or non-grey. Data was analyzed using Kruskal-Wallis tests. Out of 81 original respondents, 21% followed through with completion of the surveys in their entirety. The median time spent searching all resources was 471 minutes, and of those a median of 85 minutes were spent searching grey literature. The median number of resources used in a systematic review search was four and the median number of grey literature sources searched was two. The amount of time spent searching was influenced by whether the systematic review was grant funded. Additionally, the number of resources searched was impacted by institution type and whether systematic review training was received. This study characterized the amount of time for conducting systematic review searches including searching the grey literature, in addition to the number and types of resources used. This may aid searchers in planning their time, along with providing benchmark information for future studies. This paper contributes by quantifying current grey literature search patterns and associating them with searcher and review characteristics. Further discussion and research into the search approach for grey literature in support of systematic reviews is encouraged.

Search for gamma ray emission above 20 MeV from the Crab nebula and the NP 0532 pulsar

International Nuclear Information System (INIS)

Leray, J.-P.

1976-08-01

The search for gamma-ray emission above 20 MeV from the Crab Nebula and Pulsar NP 0532 was undertaken. A critical analysis of the detector is presented together with a study of the background. The observed flux from the sources are compared with a theoretical model for the gamma-ray emission bases on the synchrotron process in the Crab Nebula and Pulsar NP 0532 [fr

Theoretical Study of the Compound Parabolic Trough Solar Collector

OpenAIRE

Dr. Subhi S. Mahammed; Dr. Hameed J. Khalaf; Tadahmun A. Yassen

2012-01-01

Theoretical design of compound parabolic trough solar collector (CPC) without tracking is presented in this work. The thermal efficiency is obtained by using FORTRAN 90 program. The thermal efficiency is between (60-67)% at mass flow rate between (0.02-0.03) kg/s at concentration ratio of (3.8) without need to tracking system.The total and diffused radiation is calculated for Tikrit city by using theoretical equations. Good agreement between present work and the previous work.

Orientation is different: Interaction between contour integration and feature contrasts in visual search.

Science.gov (United States)

Jingling, Li; Tseng, Chia-Huei; Zhaoping, Li

2013-09-10

Salient items usually capture attention and are beneficial to visual search. Jingling and Tseng (2013), nevertheless, have discovered that a salient collinear column can impair local visual search. The display used in that study had 21 rows and 27 columns of bars, all uniformly horizontal (or vertical) except for one column of bars orthogonally oriented to all other bars, making this unique column of collinear (or noncollinear) bars salient in the display. Observers discriminated an oblique target bar superimposed on one of the bars either in the salient column or in the background. Interestingly, responses were slower for a target in a salient collinear column than in the background. This opens a theoretical question of how contour integration interacts with salience computation, which is addressed here by an examination of how salience modulated the search impairment from the collinear column. We show that the collinear column needs to have a high orientation contrast with its neighbors to exert search interference. A collinear column of high contrast in color or luminance did not produce the same impairment. Our results show that orientation-defined salience interacted with collinear contour differently from other feature dimensions, which is consistent with the neuronal properties in V1.

Theoretical and experimental studies on transient forced convection heat transfer of helium gas

International Nuclear Information System (INIS)

Liu, Qiusheng; Fukuda, Katsuya; Shibahara, Makoto

2008-01-01

Forced convection transient heat transfer for helium gas at various periods of exponential increase of heat input to a horizontal cylinder and a plate (ribbon) one was experimentally and theoretically studied. In the experimental studies, the authors measured heat flux, surface temperature, and transient heat transfer coefficients for forced convection flow of helium gas over a horizontal cylinder and a plate (ribbon) one under wide experimental conditions. Empirical correlations for quasi-steady-state heat transfer and transient heat transfer were obtained based on the experimental data. In the theoretical study, transient heat transfer was numerically solved based on a turbulent flow model. The values of numerical solution for surface temperature and heat flux were compared and discussed with authors' experimental data. (author)

When is a search not a search? A comparison of searching the AMED complementary health database via EBSCOhost, OVID and DIALOG.

Science.gov (United States)

Younger, Paula; Boddy, Kate

2009-06-01

The researchers involved in this study work at Exeter Health library and at the Complementary Medicine Unit, Peninsula School of Medicine and Dentistry (PCMD). Within this collaborative environment it is possible to access the electronic resources of three institutions. This includes access to AMED and other databases using different interfaces. The aim of this study was to investigate whether searching different interfaces to the AMED allied health and complementary medicine database produced the same results when using identical search terms. The following Internet-based AMED interfaces were searched: DIALOG DataStar; EBSCOhost and OVID SP_UI01.00.02. Search results from all three databases were saved in an endnote database to facilitate analysis. A checklist was also compiled comparing interface features. In our initial search, DIALOG returned 29 hits, OVID 14 and Ebsco 8. If we assume that DIALOG returned 100% of potential hits, OVID initially returned only 48% of hits and EBSCOhost only 28%. In our search, a researcher using the Ebsco interface to carry out a simple search on AMED would miss over 70% of possible search hits. Subsequent EBSCOhost searches on different subjects failed to find between 21 and 86% of the hits retrieved using the same keywords via DIALOG DataStar. In two cases, the simple EBSCOhost search failed to find any of the results found via DIALOG DataStar. Depending on the interface, the number of hits retrieved from the same database with the same simple search can vary dramatically. Some simple searches fail to retrieve a substantial percentage of citations. This may result in an uninformed literature review, research funding application or treatment intervention. In addition to ensuring that keywords, spelling and medical subject headings (MeSH) accurately reflect the nature of the search, database users should include wildcards and truncation and adapt their search strategy substantially to retrieve the maximum number of appropriate

A Case-Study Assignment to Teach Theoretical Perspectives in Abnormal Psychology.

Science.gov (United States)

Perkins, David V.

1991-01-01

Describes an assignment that requires students to organize, prepare, and revise a case study in abnormal behavior. Explains that students employ a single theoretical perspective in preparing a report on a figure from history, literature, the arts, or current events. Discusses the value of the assignment for students. (SG)

Medication competency of nurses according to theoretical and drug calculation online exams: A descriptive correlational study.

Science.gov (United States)

Sneck, Sami; Saarnio, Reetta; Isola, Arja; Boigu, Risto

2016-01-01

Medication administration is an important task of registered nurses. According to previous studies, nurses lack theoretical knowledge and drug calculation skills and knowledge-based mistakes do occur in clinical practice. Finnish health care organizations started to develop a systematic verification processes for medication competence at the end of the last decade. No studies have yet been made of nurses' theoretical knowledge and drug calculation skills according to these online exams. The aim of this study was to describe the medication competence of Finnish nurses according to theoretical and drug calculation exams. A descriptive correlation design was adopted. Participants and settings All nurses who participated in the online exam in three Finnish hospitals between 1.1.2009 and 31.05.2014 were selected to the study (n=2479). Quantitative methods like Pearson's chi-squared tests, analysis of variance (ANOVA) with post hoc Tukey tests and Pearson's correlation coefficient were used to test the existence of relationships between dependent and independent variables. The majority of nurses mastered the theoretical knowledge needed in medication administration, but 5% of the nurses struggled with passing the drug calculation exam. Theoretical knowledge and drug calculation skills were better in acute care units than in the other units and younger nurses achieved better results in both exams than their older colleagues. The differences found in this study were statistically significant, but not high. Nevertheless, even the tiniest deficiency in theoretical knowledge and drug calculation skills should be focused on. It is important to identify the nurses who struggle in the exams and to plan targeted educational interventions for supporting them. The next step is to study if verification of medication competence has an effect on patient safety. Copyright © 2015 Elsevier Ltd. All rights reserved.

Improved squark and gluino mass limits from searches for supersymmetry at hadron colliders

NARCIS (Netherlands)

Beenakker, W.; Brensing, S.; D'Onofrio, M.; Krämer, M.; Kulesza, A.; Laenen, E.; Martinzez, M.; Niessen, I.

2012-01-01

Squarks and gluinos have been searched for at hadron colliders in events with multiple jets and missing transverse energy. No excess has been observed to date, and from a comparison of experimental cross section limits and theoretical cross section predictions one can deduce lower bounds on the

Theoretical study of reaction dynamics in radiation chemistry

International Nuclear Information System (INIS)

Tachiya, Masanori

2008-01-01

The period from late 1950's to early 1970's was golden age of radiation chemistry. During this period the hydrated electron was discovered, various new phenomena were found in ionic processes in liquid hydrocarbons, and the trapped electron and electron tunneling were discovered in organic glasses. In those days radiation chemistry was a vast treasure-house of theoretical problems. We could find not only problems special to radiation chemistry but also many problems interesting as general physical chemistry. In this review I explain how some theoretical problems discovered in the field of radiation chemistry have evolved into those of general physical chemistry, with special emphasis on my own work. (author)

Theoretical studies of fusion physics. Volume I. Summary. Final report

International Nuclear Information System (INIS)

1983-01-01

Theoretical studies were performed on each of the following topics: (1) absorption of waves near the cyclotron frequency by relativistic electrons in EBT, (2) power balance in a stable, adiabatic hot electron annulus, (3) whistler instability in a relativistic electron annulus, (4) adiabatic limits on electron temperature in the EBT annulus, and (5) summary of a model of the EBT ring heating/loss process

A theoretical and experimental EPFM study of cracks emanating from a hole

International Nuclear Information System (INIS)

Broekhoven, M.J.G.

1978-01-01

Results are presented of a combined theoretical and experimental study on the onset of crack extension in the EPFM regime for through cracks emanating from a circular hole in a plate under tensile load, with emphasis on the applicability of the J-concept for predicting such extensions. This configuration was selected both because of its general importance and as a first approximation for a nozzle-to-vessel geometry. Theoretical investigations consisted of elastic-plastic finite element computations both for 3-point bend specimens and for plate geometry. J values were calculated using the contour-integral definition for J, and by the method of virtual crack extension. The applicability of simplified analytical approximations for J was also investigated. COD data were derived from finite element computed displacements. Experimental investigations included Jsub(Ic) tests on a series of bend specimens and crack extensions tests on a series of cracked perforated plate models. For practical reasons aluminium 2024-T 351 was selected as a suitable model material within the aims of the study. Onset of crack extension was determined by the heat-tinting procedure throughout the experiments, in some cases supplemented by fractographic investigations. The various theoretical solutions and experimental observations were compared and a number of conclusions were drawn. (author)

THEORETICAL ANALYSIS STUDY OF FORMATION OF FUTURE LEGAL LAWYERS

Directory of Open Access Journals (Sweden)

Eugene Stepanovich Shevlakov

2015-09-01

Full Text Available The article deals with topical issues of formation of legal consciousness of future lawyers in high school. Obtained kinds of legal consciousness of future lawyers, determined its structure. Dedicated components of justice are mutually reinforcing, and provide an opportunity for further development of the personality of the future specialist, their personal growth.The purpose: to carry out theoretical analysis of the problem of formation of legal consciousness of future lawyers.The novelty is based. On the analysis of theoretical appro-aches of pedagogy, psychology, law, the notion of «lawfulness of the future of the law student», which is regarded as a form of social consciousness, which is a set of legal views and feelings, expressing the attitude to the law and legal phenomena that have regulatory in character and which includes know-ledge of legal phenomena and their evaluation from the point of view of fairness and justice, formed in the process of studying in the University.Results: this article analyzes different approaches to understanding the content and essence of the concept of legal consciousness of the legal profession. Define the types and structure of legal consciousness of future lawyers.

EEC-sponsored theoretical studies of gas cloud explosion pressure loadings

International Nuclear Information System (INIS)

Briscoe, F.; Curtress, N.; Farmer, C.L.; Fogg, G.J.; Vaughan, G.J.

1979-01-01

Estimates of the pressure loadings produced by unconfined gas cloud explosions on the surface of structures are required to assist the design of strong secondary containments in countries where the protection of nuclear installations against these events is considered to be necessary. At the present time, one difficulty in the specification of occurate pressure loadings arises from our lack of knowledge concerning the interaction between the incident pressure waves produced by unconfined gas cloud explosions and large structures. Preliminary theoretical studies include (i) general theoretical considerations, especially with regard to scaling (ii) investigations of the deflagration wave interaction with a wall based on an analytic solution for situations with planar symmetry and the application of an SRD gas cloud explosion code (GASEX 1) for situations with planar and spherical symmetry, and (iii) investigations of the interaction between shock waves and structures for situations with two-dimensional symmetry based on the application of another SRD gas cloud explosion code (GASEX 2)

Searching for religion and mental health studies required health, social science, and grey literature databases.

Science.gov (United States)

Wright, Judy M; Cottrell, David J; Mir, Ghazala

2014-07-01

To determine the optimal databases to search for studies of faith-sensitive interventions for treating depression. We examined 23 health, social science, religious, and grey literature databases searched for an evidence synthesis. Databases were prioritized by yield of (1) search results, (2) potentially relevant references identified during screening, (3) included references contained in the synthesis, and (4) included references that were available in the database. We assessed the impact of databases beyond MEDLINE, EMBASE, and PsycINFO by their ability to supply studies identifying new themes and issues. We identified pragmatic workload factors that influence database selection. PsycINFO was the best performing database within all priority lists. ArabPsyNet, CINAHL, Dissertations and Theses, EMBASE, Global Health, Health Management Information Consortium, MEDLINE, PsycINFO, and Sociological Abstracts were essential for our searches to retrieve the included references. Citation tracking activities and the personal library of one of the research teams made significant contributions of unique, relevant references. Religion studies databases (Am Theo Lib Assoc, FRANCIS) did not provide unique, relevant references. Literature searches for reviews and evidence syntheses of religion and health studies should include social science, grey literature, non-Western databases, personal libraries, and citation tracking activities. Copyright © 2014 Elsevier Inc. All rights reserved.

Theoretical studies of zirconium and carbon clusters with molecular dynamics simulations

International Nuclear Information System (INIS)

Zhang, B.

1993-08-01

In this dissertation, we will present a systematic study of structures of fullerenes ranging from C 20 to C 100 by introducing a novel scheme. Using our new scheme, we not only reproduce all known fullerene structures but also successfully predicted several other fullerene structures which were confirmed by experiments. By utilizing the tight-binding molecular-dynamic (TBMD) simulation, we also studied the dynamical behavior of fullerenes: Vibrations, thermal disintegration of individual clusters as well as collisions between fullerenes. If the beauty of carbon fullerene is not enough, people found that carbon can also form tubules and even speculated that they can form three-dimensional graphite-like networks. By extending our fullerene structure searching scheme, we performed a search for the ground-state structure of three dimensional carbon network. We found the most stable structure people ever proposed for simple cubic based networks. From the difference of this new form of carbon and graphite in the electronic and vibrational properties, we propose an experimental probe to identify these novel three-dimensional carbon networks

Theoretical Study of the Compound Parabolic Trough Solar Collector

Directory of Open Access Journals (Sweden)

Dr. Subhi S. Mahammed

2012-06-01

Full Text Available Theoretical design of compound parabolic trough solar collector (CPC without tracking is presented in this work. The thermal efficiency is obtained by using FORTRAN 90 program. The thermal efficiency is between (60-67% at mass flow rate between (0.02-0.03 kg/s at concentration ratio of (3.8 without need to tracking system.The total and diffused radiation is calculated for Tikrit city by using theoretical equations. Good agreement between present work and the previous work.

Development and use of a content search strategy for retrieving studies on patients' views and preferences.

Science.gov (United States)

Selva, Anna; Solà, Ivan; Zhang, Yuan; Pardo-Hernandez, Hector; Haynes, R Brian; Martínez García, Laura; Navarro, Tamara; Schünemann, Holger; Alonso-Coello, Pablo

2017-08-30

Identifying scientific literature addressing patients' views and preferences is complex due to the wide range of studies that can be informative and the poor indexing of this evidence. Given the lack of guidance we developed a search strategy to retrieve this type of evidence. We assembled an initial list of terms from several sources, including the revision of the terms and indexing of topic-related studies and, methods research literature, and other relevant projects and systematic reviews. We used the relative recall approach, evaluating the capacity of the designed search strategy for retrieving studies included in relevant systematic reviews for the topic. We implemented in practice the final version of the search strategy for conducting systematic reviews and guidelines, and calculated search's precision and the number of references needed to read (NNR). We assembled an initial version of the search strategy, which had a relative recall of 87.4% (yield of 132/out of 151 studies). We then added some additional terms from the studies not initially identified, and re-tested this improved version against the studies included in a new set of systematic reviews, reaching a relative recall of 85.8% (151/out of 176 studies, 95% CI 79.9 to 90.2). This final version of the strategy includes two sets of terms related with two domains: "Patient Preferences and Decision Making" and "Health State Utilities Values". When we used the search strategy for the development of systematic reviews and clinical guidelines we obtained low precision values (ranging from 2% to 5%), and the NNR from 20 to 50. This search strategy fills an important research gap in this field. It will help systematic reviewers, clinical guideline developers, and policy-makers to retrieve published research on patients' views and preferences. In turn, this will facilitate the inclusion of this critical aspect when formulating heath care decisions, including recommendations.

Search for gamma-ray spectral lines with the Fermi Large Area Telescope and dark matter implications

Energy Technology Data Exchange (ETDEWEB)

Ackermann, M.; Ajello, M.; Albert, A.; Allafort, A.; Baldini, L.; Barbiellini, G.; Bastieri, D.; Bechtol, K.; Bellazzini, R.; Bissaldi, E.; Bloom, E. D.; Bonamente, E.; Bottacini, E.; Brandt, T. J.; Bregeon, J.; Brigida, M.; Bruel, P.; Buehler, R.; Buson, S.; Caliandro, G. A.; Cameron, R. A.; Caraveo, P. A.; Casandjian, J. M.; Cecchi, C.; Charles, E.; Chaves, R. C. G.; Chekhtman, A.; Chiang, J.; Ciprini, S.; Claus, R.; Cohen-Tanugi, J.; Conrad, J.; Cutini, S.; D’Ammando, F.; de Angelis, A.; de Palma, F.; Dermer, C. D.; Digel, S. W.; Di Venere, L.; Drell, P. S.; Drlica-Wagner, A.; Essig, R.; Favuzzi, C.; Fegan, S. J.; Ferrara, E. C.; Focke, W. B.; Franckowiak, A.; Fukazawa, Y.; Funk, S.; Fusco, P.; Gargano, F.; Gasparrini, D.; Germani, S.; Giglietto, N.; Giordano, F.; Giroletti, M.; Glanzman, T.; Godfrey, G.; Gomez-Vargas, G. A.; Grenier, I. A.; Guiriec, S.; Gustafsson, M.; Hadasch, D.; Hayashida, M.; Hill, A. B.; Horan, D.; Hou, X.; Hughes, R. E.; Inoue, Y.; Izaguirre, E.; Jogler, T.; Kamae, T.; Knödlseder, J.; Kuss, M.; Lande, J.; Larsson, S.; Latronico, L.; Longo, F.; Loparco, F.; Lovellette, M. N.; Lubrano, P.; Malyshev, D.; Mayer, M.; Mazziotta, M. N.; McEnery, J. E.; Michelson, P. F.; Mitthumsiri, W.; Mizuno, T.; Moiseev, A. A.; Monzani, M. E.; Morselli, A.; Moskalenko, I. V.; Murgia, S.; Nakamori, T.; Nemmen, R.; Nuss, E.; Ohsugi, T.; Okumura, A.; Omodei, N.; Orienti, M.; Orlando, E.; Ormes, J. F.; Paneque, D.; Perkins, J. S.; Pesce-Rollins, M.; Piron, F.; Pivato, G.; Rainò, S.; Rando, R.; Razzano, M.; Razzaque, S.; Reimer, A.; Reimer, O.; Romani, R. W.; Sánchez-Conde, M.; Schulz, A.; Sgrò, C.; Siegal-Gaskins, J.; Siskind, E. J.; Snyder, A.; Spandre, G.; Spinelli, P.; Suson, D. J.; Tajima, H.; Takahashi, H.; Thayer, J. G.; Thayer, J. B.; Tibaldo, L.; Tinivella, M.; Tosti, G.; Troja, E.; Uchiyama, Y.; Usher, T. L.; Vandenbroucke, J.; Vasileiou, V.; Vianello, G.; Vitale, V.; Winer, B. L.; Wood, K. S.; Wood, M.; Yang, Z.; Zaharijas, G.; Zimmer, S.

2013-10-22

Weakly interacting massive particles (WIMPs) are a theoretical class of particles that are excellent dark matter candidates. WIMP annihilation or decay may produce essentially monochromatic γ rays detectable by the Fermi Large Area Telescope (LAT) against the astrophysical γ -ray emission of the Galaxy. We have searched for spectral lines in the energy range 5–300 GeV using 3.7 years of data, reprocessed with updated instrument calibrations and an improved energy dispersion model compared to the previous Fermi-LAT Collaboration line searches. We searched in five regions selected to optimize sensitivity to different theoretically motivated dark matter density distributions. We did not find any globally significant lines in our a priori search regions and present 95% confidence limits for annihilation cross sections of self-conjugate WIMPs and decay lifetimes. Our most significant fit occurred at 133 GeV in our smallest search region and had a local significance of 3.3 standard deviations, which translates to a global significance of 1.5 standard deviations. We discuss potential systematic effects in this search, and examine the feature at 133 GeV in detail. We find that the use both of reprocessed data and of additional information in the energy dispersion model contributes to the reduction in significance of the linelike feature near 130 GeV relative to significances reported in other works. We also find that the feature is narrower than the LAT energy resolution at the level of 2 to 3 standard deviations, which somewhat disfavors the interpretation of the 133 GeV feature as a real WIMP signal.

Quark-gluon plasma searches: today and tomorrow

International Nuclear Information System (INIS)

Geist, W.M.

1991-01-01

Selected recent data from ion collisions at high energy are discussed in the frame-work of Quark-Gluon Plasma (QGP) searches. The purpose of these experiments is to measure the volume where a high temperature QGP may have been formed, determine its characteristic temperature, verify chemical equilibrium, establish deconfinement of this phase of matter, and/or find anything that differs from natural extrapolations from pp and pA collisions. Refined methods and new theoretical ideas for future experiments with heavier beams and/or at higher energies are briefly outlined. (G.P.) 49 refs., 28 figs

Theoretical and experimental studies on critical heat flux in subcooled boiling and vertical flow geometry

International Nuclear Information System (INIS)

Staron, E.

1996-01-01

Critical Heat Flux is a very important subject of interest due to design, operation and safety analysis of nuclear power plants. Every new design of the core must be thoroughly checked. Experimental studies have been performed using freon as a working fluid. The possibility of transferring of results into water equivalents has been proved. The experimental study covers vertical flow, annular geometry over a wide range of pressure, mass flow and temperature at inlet of test section. Theoretical models of Critical Heat Flux have been presented but only those which cover DNB. Computer programs allowing for numerical calculations using theoretical models have been developed. A validation of the theoretical models has been performed in accordance with experimental results. (author). 83 refs, 32 figs, 4 tabs

Experimental and theoretical total neutron scattering cross-section of water confined in silica microspheres

Energy Technology Data Exchange (ETDEWEB)

Muhrer, G., E-mail: muhrer@lanl.gov [Los Alamos National Laboratory, Los Alamos, 87545 NM (United States); Hartl, M.; Mocko, M.; Tovesson, F.; Daemen, L. [Los Alamos National Laboratory, Los Alamos, 87545 NM (United States)

2012-07-21

In the search for moderator materials encapsulated materials have been discussed, but very little is known regarding the effect of encapsulation on neutron moderation properties. As a first step toward a better understanding, we present the measured total neutron cross-section of water confined in silica microspheres and compare the measured data to the predicted theoretical cross-section.

Information-seeking Behavior During Residency Is Associated With Quality of Theoretical Learning, Academic Career Achievements, and Evidence-based Medical Practice

Science.gov (United States)

Oussalah, Abderrahim; Fournier, Jean-Paul; Guéant, Jean-Louis; Braun, Marc

2015-01-01

Abstract Data regarding knowledge acquisition during residency training are sparse. Predictors of theoretical learning quality, academic career achievements and evidence-based medical practice during residency are unknown. We performed a cross-sectional study on residents and attending physicians across several residency programs in 2 French faculties of medicine. We comprehensively evaluated the information-seeking behavior (I-SB) during residency using a standardized questionnaire and looked for independent predictors of theoretical learning quality, academic career achievements, and evidence-based medical practice among I-SB components using multivariate logistic regression analysis. Between February 2013 and May 2013, 338 fellows and attending physicians were included in the study. Textbooks and international medical journals were reported to be used on a regular basis by 24% and 57% of the respondents, respectively. Among the respondents, 47% refer systematically (4.4%) or frequently (42.6%) to published guidelines from scientific societies upon their publication. The median self-reported theoretical learning quality score was 5/10 (interquartile range, 3–6; range, 1–10). A high theoretical learning quality score (upper quartile) was independently and strongly associated with the following I-SB components: systematic reading of clinical guidelines upon their publication (odds ratio [OR], 5.55; 95% confidence interval [CI], 1.77–17.44); having access to a library that offers the leading textbooks of the specialty in the medical department (OR, 2.45, 95% CI, 1.33–4.52); knowledge of the specialty leading textbooks (OR, 2.12; 95% CI, 1.09–4.10); and PubMed search skill score ≥5/10 (OR, 1.94; 95% CI, 1.01–3.73). Research Master (M2) and/or PhD thesis enrolment were independently and strongly associated with the following predictors: PubMed search skill score ≥5/10 (OR, 4.10; 95% CI, 1.46–11.53); knowledge of the leading medical journals of the

A history of the ideas of theoretical physics essays on the nineteenth and twentieth century physics

CERN Document Server

D’Agostino, Salvo

2000-01-01

This book presents a perspective on the history of theoretical physics over the past two hundreds years. It comprises essays on the history of pre-Maxwellian electrodynamics, of Maxwell's and Hertz's field theories, and of the present century's relativity and quantum physics. A common thread across the essays is the search for and the exploration of themes that influenced significant con­ ceptual changes in the great movement of ideas and experiments which heralded the emergence of theoretical physics (hereafter: TP). The fun. damental change involved the recognition of the scien­ tific validity of theoretical physics. In the second half of the nine­ teenth century, it was not easy for many physicists to understand the nature and scope of theoretical physics and of its adept, the theoreti­ cal physicist. A physicist like Ludwig Boltzmann, one of the eminent contributors to the new discipline, confessed in 1895 that, "even the formulation of this concept [of a theoretical physicist] is not entirely without...

End-User Searching in a Large Library Network: A Case Study of Patent Attorneys.

Science.gov (United States)

Vollaro, Alice J.; Hawkins, Donald T.

1986-01-01

Reports results of study of a group of end users (patent attorneys) doing their own online searching at AT&T Bell Laboratories. Highlights include DIALOG databases used by the attorneys, locations and searching modes, characteristics of patent attorney searchers, and problem areas. Questionnaire is appended. (5 references) (EJS)

Higgs Boson Searches at Hadron Colliders (1/4)

CERN Multimedia

CERN. Geneva

2010-01-01

In these Academic Training lectures, the phenomenology of Higgs bosons and search strategies at hadron colliders are discussed. After a brief introduction on Higgs bosons in the Standard Model and a discussion of present direct and indirect constraints on its mass the status of the theoretical cross section calculations for Higgs boson production at hadron colliders is reviewed. In the following lectures important experimental issues relevant for Higgs boson searches (trigger, measurements of leptons, jets and missing transverse energy) are presented. This is followed by a detailed discussion of the discovery potential for the Standard Model Higgs boson for both the Tevatron and the LHC experiments. In addition, various scenarios beyond the Standard Model, primarily the MSSM, are considered. Finally, the potential and strategies to measured Higgs boson parameters and the investigation of alternative symmetry breaking scenarios are addressed.

Indirect dark matter searches: current status and perspectives

CERN Multimedia

CERN. Geneva

2016-01-01

Many theoretical ideas for the particle nature of dark matter exist. The  most popular models often predict that dark matter particles self-annihilate or decay, giving rise to potentially detectable signatures in astronomical observations.  I will summarize the current status of searches for such signatures and critically reassess recent claims for dark matter signals.  I will further provide an outlook on anticipated developments in the next 10 years, and discuss new methods to facilitate strategy development.

Theoretical and experimental study of an energy-reinforced braking radiation photon beam

International Nuclear Information System (INIS)

Bertin, Pierre-Yves

1966-01-01

This research thesis reports the theoretical study of a photon beam raised towards high energies, its experimental implementation, the definition of a gamma spectrometry method which aimed at checking various hypotheses used in the beam theoretical study. After a presentation of the theory of phenomena of electron braking radiation, of materialisation of photons into positon-negaton pair, and of issues related to multiple Coulomb diffusion, the author reports the study of the different solutions which allow a photon beam to be obtained. A braking radiation of mono-kinetic electron has been used. This braking radiation is reinforced by absorption of low energy protons in a column of lithium hydride. The author describes how the beam is built up, and the experimental approach. He describes how raw data are processed to get rid of the influence of the multiple Coulomb diffusion and of the braking radiation. Experimental results are compared with those obtained by convolution of photon spectra and differential cross section

Using search engine query data to track pharmaceutical utilization: a study of statins.

Science.gov (United States)

Schuster, Nathaniel M; Rogers, Mary A M; McMahon, Laurence F

2010-08-01

To examine temporal and geographic associations between Google queries for health information and healthcare utilization benchmarks. Retrospective longitudinal study. Using Google Trends and Google Insights for Search data, the search terms Lipitor (atorvastatin calcium; Pfizer, Ann Arbor, MI) and simvastatin were evaluated for change over time and for association with Lipitor revenues. The relationship between query data and community-based resource use per Medicare beneficiary was assessed for 35 US metropolitan areas. Google queries for Lipitor significantly decreased from January 2004 through June 2009 and queries for simvastatin significantly increased (P patent (P global revenues from 2004 to 2008 (P search engine queries for medical information correlate with pharmaceutical revenue and with overall healthcare utilization in a community. This suggests that search query data can track community-wide characteristics in healthcare utilization and have the potential for informing payers and policy makers regarding trends in utilization.

Prices and heterogeneous search costs

NARCIS (Netherlands)

Luis Moraga-Gonzalez, Jose; Sandor, Zsolt; Wildenbeest, Matthijs R.

2017-01-01

We study price formation in a model of consumer search for differentiated products in which consumers have heterogeneous search costs. We provide conditions under which a pure-strategy symmetric Nash equilibrium exists and is unique. Search costs affect two margins-the intensive search margin (or

Theoretical study on the first kind of density wave instabilities

Energy Technology Data Exchange (ETDEWEB)

Zuying, Gao; Jincai, Li; Baocheng, Xu; Zuoyi, Zhang; Cheng, Gao [Institute of Nuclear Energy and Technology, Tsingua Univ., Beijing (China)

1997-09-01

The present paper summarizes the theoretical studies carried out by INET (Institute of Nuclear Energy Technology) of Tsinghua University on the first kind of density wave instabilities (DWIs) of natural circulation systems. The analysis methods of DWI and mathematical models of drift flux are presented. Based on the general excess entropy production criterion of non-equilibrium thermodynamics, an energy principle of DWI is established. (author). 10 refs, 16 figs.

Short-term Internet search using makes people rely on search engines when facing unknown issues.

Science.gov (United States)

Wang, Yifan; Wu, Lingdan; Luo, Liang; Zhang, Yifen; Dong, Guangheng

2017-01-01

The Internet search engines, which have powerful search/sort functions and ease of use features, have become an indispensable tool for many individuals. The current study is to test whether the short-term Internet search training can make people more dependent on it. Thirty-one subjects out of forty subjects completed the search training study which included a pre-test, a six-day's training of Internet search, and a post-test. During the pre- and post- tests, subjects were asked to search online the answers to 40 unusual questions, remember the answers and recall them in the scanner. Un-learned questions were randomly presented at the recalling stage in order to elicited search impulse. Comparing to the pre-test, subjects in the post-test reported higher impulse to use search engines to answer un-learned questions. Consistently, subjects showed higher brain activations in dorsolateral prefrontal cortex and anterior cingulate cortex in the post-test than in the pre-test. In addition, there were significant positive correlations self-reported search impulse and brain responses in the frontal areas. The results suggest that a simple six-day's Internet search training can make people dependent on the search tools when facing unknown issues. People are easily dependent on the Internet search engines.

Short-term Internet search using makes people rely on search engines when facing unknown issues.

Directory of Open Access Journals (Sweden)

Yifan Wang

Full Text Available The Internet search engines, which have powerful search/sort functions and ease of use features, have become an indispensable tool for many individuals. The current study is to test whether the short-term Internet search training can make people more dependent on it. Thirty-one subjects out of forty subjects completed the search training study which included a pre-test, a six-day's training of Internet search, and a post-test. During the pre- and post- tests, subjects were asked to search online the answers to 40 unusual questions, remember the answers and recall them in the scanner. Un-learned questions were randomly presented at the recalling stage in order to elicited search impulse. Comparing to the pre-test, subjects in the post-test reported higher impulse to use search engines to answer un-learned questions. Consistently, subjects showed higher brain activations in dorsolateral prefrontal cortex and anterior cingulate cortex in the post-test than in the pre-test. In addition, there were significant positive correlations self-reported search impulse and brain responses in the frontal areas. The results suggest that a simple six-day's Internet search training can make people dependent on the search tools when facing unknown issues. People are easily dependent on the Internet search engines.

Energy spectrum of reactor antineutrinos and searches for new physics (Resent developments)

International Nuclear Information System (INIS)

Kopejkin, V.I.; Sinev, V.V.

2001-01-01

The study of the electron neutrino properties - its mass, mixing, magnetic moment - is the main goal of the present reactor antineutrino experiments. We consider the time evolution of the reactor ν bar e spectrum during reactor ON and reactor OFF periods. An important role of the time variations of the reactor ν bar e spectrum in searches for neutrino magnetic moment is discussed. Corrections to the predicted earlier theoretical and precise measured inverse beta-decay cross sections are calculated. We found that the residual ν bar e emission during the reactor OFF period can play a non-negligible role in oscillation experiments

Search for Majorana fermions in topological superconductors.

Energy Technology Data Exchange (ETDEWEB)

Pan, Wei [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Shi, Xiaoyan [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hawkins, Samuel D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Klem, John Frederick [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2014-10-01

The goal of this project is to search for Majorana fermions (a new quantum particle) in a topological superconductor (a new quantum matter achieved in a topological insulator proximitized by an s-wave superconductor). Majorana fermions (MFs) are electron-like particles that are their own anti-particles. MFs are shown to obey non-Abelian statistics and, thus, can be harnessed to make a fault-resistant topological quantum computer. With the arrival of topological insulators, novel schemes to create MFs have been proposed in hybrid systems by combining a topological insulator with a conventional superconductor. In this LDRD project, we will follow the theoretical proposals to search for MFs in one-dimensional (1D) topological superconductors. 1D topological superconductor will be created inside of a quantum point contact (with the metal pinch-off gates made of conventional s-wave superconductors such as niobium) in a two-dimensional topological insulator (such as inverted type-II InAs/GaSb heterostructure).

Supplementary searches of PubMed to improve currency of MEDLINE and MEDLINE In-Process searches via Ovid.

Science.gov (United States)

Duffy, Steven; de Kock, Shelley; Misso, Kate; Noake, Caro; Ross, Janine; Stirk, Lisa

2016-10-01

The research investigated whether conducting a supplementary search of PubMed in addition to the main MEDLINE (Ovid) search for a systematic review is worthwhile and to ascertain whether this PubMed search can be conducted quickly and if it retrieves unique, recently published, and ahead-of-print studies that are subsequently considered for inclusion in the final systematic review. Searches of PubMed were conducted after MEDLINE (Ovid) and MEDLINE In-Process (Ovid) searches had been completed for seven recent reviews. The searches were limited to records not in MEDLINE or MEDLINE In-Process (Ovid). Additional unique records were identified for all of the investigated reviews. Search strategies were adapted quickly to run in PubMed, and reviewer screening of the results was not time consuming. For each of the investigated reviews, studies were ordered for full screening; in six cases, studies retrieved from the supplementary PubMed searches were included in the final systematic review. Supplementary searching of PubMed for studies unavailable elsewhere is worthwhile and improves the currency of the systematic reviews.

Panoramic Search: The Interaction of Memory and Vision in Search through a Familiar Scene

Science.gov (United States)

Oliva, Aude; Wolfe, Jeremy M. Arsenio, Helga C.

2004-01-01

How do observers search through familiar scenes? A novel panoramic search method is used to study the interaction of memory and vision in natural search behavior. In panoramic search, observers see part of an unchanging scene larger than their current field of view. A target object can be visible, present in the display but hidden from view, or…

Theoretical explanations for maintenance of behaviour change: a systematic review of behaviour theories

OpenAIRE

Kwasnicka, Dominika; Dombrowski, Stephan U; White, Martin; Sniehotta, Falko

2016-01-01

ABSTRACT Background: Behaviour change interventions are effective in supporting individuals in achieving temporary behaviour change. Behaviour change maintenance, however, is rarely attained. The aim of this review was to identify and synthesise current theoretical explanations for behaviour change maintenance to inform future research and practice. Methods: Potentially relevant theories were identified through systematic searches of electronic databases (Ovid MEDLINE, Embase, PsycINFO). In a...

Strategies to optimize MEDLINE and EMBASE search strategies for anesthesiology systematic reviews. An experimental study.

Science.gov (United States)

Volpato, Enilze de Souza Nogueira; Betini, Marluci; Puga, Maria Eduarda; Agarwal, Arnav; Cataneo, Antônio José Maria; Oliveira, Luciane Dias de; Bazan, Rodrigo; Braz, Leandro Gobbo; Pereira, José Eduardo Guimarães; El Dib, Regina

2018-01-15

A high-quality electronic search is essential for ensuring accuracy and comprehensiveness among the records retrieved when conducting systematic reviews. Therefore, we aimed to identify the most efficient method for searching in both MEDLINE (through PubMed) and EMBASE, covering search terms with variant spellings, direct and indirect orders, and associations with MeSH and EMTREE terms (or lack thereof). Experimental study. UNESP, Brazil. We selected and analyzed 37 search strategies that had specifically been developed for the field of anesthesiology. These search strategies were adapted in order to cover all potentially relevant search terms, with regard to variant spellings and direct and indirect orders, in the most efficient manner. When the strategies included variant spellings and direct and indirect orders, these adapted versions of the search strategies selected retrieved the same number of search results in MEDLINE (mean of 61.3%) and a higher number in EMBASE (mean of 63.9%) in the sample analyzed. The numbers of results retrieved through the searches analyzed here were not identical with and without associated use of MeSH and EMTREE terms. However, association of these terms from both controlled vocabularies retrieved a larger number of records than did the use of either one of them. In view of these results, we recommend that the search terms used should include both preferred and non-preferred terms (i.e. variant spellings and direct/indirect order of the same term) and associated MeSH and EMTREE terms, in order to develop highly-sensitive search strategies for systematic reviews.

Theoretical study of excitonic complexes in semiconductors quantum wells

International Nuclear Information System (INIS)

Dacal, Luis Carlos Ogando

2001-08-01

A physical system where indistinguishable particles interact with each other creates the possibility of studying correlation and exchange effect. The simplest system is that one with only two indistinguishable particles. In condensed matter physics, these complexes are represented by charged excitons, donors and acceptors. In quantum wells, the valence band is not parabolic, therefore, the negatively charged excitons and donors are theoretically described in a simpler way. Despite the fact that the stability of charged excitons (trions) is known since the late 50s, the first experimental observation occurred only at the early 90s in quantum well samples, where their binding energies are one order of magnitude larger due to the one dimensional carriers confinement. After this, these complexes became the subject of an intense research because the intrinsic screening of electrical interactions in semiconductor materials allows that magnetic fields that are usual in laboratories have strong effects on the trion binding energy. Another rich possibility is the study of trions as an intermediate state between the neutral exciton and the Fermi edge singularity when the excess of doping carriers is increased. In this thesis, we present a theoretical study of charged excitons and negatively charged donors in GaAs/Al 0.3 Ga 0.7 As quantum wells considering the effects of external electric and magnetic fields. We use a simple, accurate and physically clear method to describe these systems in contrast with the few and complex treatments s available in the literature. Our results show that the QW interface defects have an important role in the trion dynamics. This is in agreement with some experimental works, but it disagrees with other ones. (author)

Delaying information search

Directory of Open Access Journals (Sweden)

Yaniv Shani

2012-11-01

Full Text Available In three studies, we examined factors that may temporarily attenuate information search. People are generally curious and dislike uncertainty, which typically encourages them to look for relevant information. Despite these strong forces that promote information search, people sometimes deliberately delay obtaining valuable information. We find they may do so when they are concerned that the information might interfere with future pleasurable activities. Interestingly, the decision to search or to postpone searching for information is influenced not only by the value and importance of the information itself but also by well-being maintenance goals related to possible detrimental effects that negative knowledge may have on unrelated future plans.

One visual search, many memory searches: An eye-tracking investigation of hybrid search.

Science.gov (United States)

Drew, Trafton; Boettcher, Sage E P; Wolfe, Jeremy M

2017-09-01

Suppose you go to the supermarket with a shopping list of 10 items held in memory. Your shopping expedition can be seen as a combination of visual search and memory search. This is known as "hybrid search." There is a growing interest in understanding how hybrid search tasks are accomplished. We used eye tracking to examine how manipulating the number of possible targets (the memory set size [MSS]) changes how observers (Os) search. We found that dwell time on each distractor increased with MSS, suggesting a memory search was being executed each time a new distractor was fixated. Meanwhile, although the rate of refixation increased with MSS, it was not nearly enough to suggest a strategy that involves repeatedly searching visual space for subgroups of the target set. These data provide a clear demonstration that hybrid search tasks are carried out via a "one visual search, many memory searches" heuristic in which Os examine items in the visual array once with a very low rate of refixations. For each item selected, Os activate a memory search that produces logarithmic response time increases with increased MSS. Furthermore, the percentage of distractors fixated was strongly modulated by the MSS: More items in the MSS led to a higher percentage of fixated distractors. Searching for more potential targets appears to significantly alter how Os approach the task, ultimately resulting in more eye movements and longer response times.

Theoretical and experimental study of collectrons for epithermal neutron flux in reactors

International Nuclear Information System (INIS)

Agu, M.N.

1986-01-01

A theoretical study of nuclear reactions and electric charge displacements arising in sensitivity to thermal and epithermal neutrons in collectrons allowed a computer code conception. Collectrons in Rhodium, Silver, Cobalt, Hafnium, Erbium, Gadolinium and Holmium have been tested in different radiation fields given by neutron or gamma filters irradiated in different places of Melusine and Siloe reactors. Some emitters were covered with different steel, nickel or zircaloy thicknesses. Theoretical and experimental results are consistent; that validate the computer code and show possibilities and necessity of covering collectron emitters to reduce or cancel the gamma sensitivity and to improve response instantaneity. A selective measurement of epithermal neutron flux can by this way, made by associating two types of collectrons [fr

Ratcheting Up The Search for Dark Matter

Energy Technology Data Exchange (ETDEWEB)

McDermott, Samuel Dylan [Univ. of Michigan, Ann Arbor, MI (United States)

2014-01-01

The last several years have included remarkable advances in two of the primary areas of fundamental particle physics: the search for dark matter and the discovery of the Higgs boson. This dissertation will highlight some contributions made on the forefront of these exciting fields. Although the circumstantial evidence supporting the dark matter hypothesis is now almost undeniably significant, indisputable direct proof is still lacking. As the direct searches for dark matter continue, we can maximize our prospects of discovery by using theoretical techniques complementary to the observational searches to rule out additional, otherwise accessible parameter space. In this dissertation, I report bounds on a wide range of dark matter theories. The models considered here cover the spectrum from the canonical case of self-conjugate dark matter with weak-scale interactions, to electrically charged dark matter, to non-annihilating, non-fermionic dark matter. These bounds are obtained from considerations of astrophysical and cosmological data, including, respectively: diffuse gamma ray photon observations; structure formation considerations, along with an explication of the novel local dark matter structure due to galactic astrophysics; and the existence of old pulsars in dark-matter-rich environments. I also consider the prospects for a model of neutrino dark matter which has been motivated by a wide set of seemingly contradictory experimental results. In addition, I include a study that provides the tools to begin solving the speculative ``inverse'' problem of extracting dark matter properties solely from hypothetical nuclear energy spectra, which we may face if dark matter is discovered with multiple direct detection experiments. In contrast to the null searches for dark matter, we have the example of the recent discovery of the Higgs boson. The Higgs boson is the first fundamental scalar particle ever observed, and precision measurements of the production and

Search for quasi bound η mesons

International Nuclear Information System (INIS)

Machner, H

2015-01-01

The search for a quasi bound η meson in atomic nuclei is reviewed. This tentative state is studied theoretically as well as experimentally. The theory starts from elastic η nucleon scattering which is derived from production data within some models. From this interaction the η nucleus interaction is derived. Model calculations predict binding energies and widths of the quasi bound state. Another method is to derive the η nucleus interaction from excitation functions of η production experiments. The s wave interaction is extracted from such data via final state interaction (FSI) theorem. We give the derivation of s wave amplitudes in partial wave expansion and in helicity amplitudes and their relation to observables. Different experiments extracting the FSI are discussed as are production experiments. So far only three experiments give evidence for the existence of the quasi bound state: a pion double charge exchange experiment, an effective mass measurement, and a transfer reaction at recoil free kinematics with observation of the decay of the state. (topical review)

A theoretical-experimental study of backup bearings

DEFF Research Database (Denmark)

Lampe Linhares da Fonseca, Cesar Augusto

of two types of backup bearings, which are investigated experimentally and theoretically. The first type is a conventional ball bearing commonly used in industrial applications. The second is an unconventional bearing that, which contains pins inside the clearance for the rotor to impact on. The main...... both types of bearings for further investigation. Also, a full failure of the control and a rotor drop on the ball bearing as backup bearing is investigated by removing the magnetic forces. The nonlinear features of the dynamics of the rotor are assessed for different levels of unbalance. It has been...... radial forces. Remaining in this condition, it may lead to permanent damage or total failure of the machine. This is why the backup bearing design has to be carefully planned and investigated as to whether it helps to protect the integrity of the machine. This PhD thesis provides a comprehensive study...

Internet search patterns of human immunodeficiency virus and the digital divide in the Russian Federation: infoveillance study.

Science.gov (United States)

Zheluk, Andrey; Quinn, Casey; Hercz, Daniel; Gillespie, James A

2013-11-12

Human immunodeficiency virus (HIV) is a serious health problem in the Russian Federation. However, the true scale of HIV in Russia has long been the subject of considerable debate. Using digital surveillance to monitor diseases has become increasingly popular in high income countries. But Internet users may not be representative of overall populations, and the characteristics of the Internet-using population cannot be directly ascertained from search pattern data. This exploratory infoveillance study examined if Internet search patterns can be used for disease surveillance in a large middle-income country with a dispersed population. This study had two main objectives: (1) to validate Internet search patterns against national HIV prevalence data, and (2) to investigate the relationship between search patterns and the determinants of Internet access. We first assessed whether online surveillance is a valid and reliable method for monitoring HIV in the Russian Federation. Yandex and Google both provided tools to study search patterns in the Russian Federation. We evaluated the relationship between both Yandex and Google aggregated search patterns and HIV prevalence in 2011 at national and regional tiers. Second, we analyzed the determinants of Internet access to determine the extent to which they explained regional variations in searches for the Russian terms for "HIV" and "AIDS". We sought to extend understanding of the characteristics of Internet searching populations by data matching the determinants of Internet access (age, education, income, broadband access price, and urbanization ratios) and searches for the term "HIV" using principal component analysis (PCA). We found generally strong correlations between HIV prevalence and searches for the terms "HIV" and "AIDS". National correlations for Yandex searches for "HIV" were very strongly correlated with HIV prevalence (Spearman rank-order coefficient [rs]=.881, P ≤ .001) and strongly correlated for "AIDS" (rs

Hash functions and information theoretic security

DEFF Research Database (Denmark)

Bagheri, Nasoor; Knudsen, Lars Ramkilde; Naderi, Majid

2009-01-01

Information theoretic security is an important security notion in cryptography as it provides a true lower bound for attack complexities. However, in practice attacks often have a higher cost than the information theoretic bound. In this paper we study the relationship between information theoretic...

Hadron collider searches for diboson resonances

Science.gov (United States)

Dorigo, Tommaso

2018-05-01

This review covers results of searches for new elementary particles that decay into boson pairs (dibosons), performed at the CERN Large Hadron Collider in proton-proton collision data collected by the ATLAS and CMS experiments at 7-, 8-, and 13-TeV center-of-mass energy until the year 2017. The available experimental results of the analysis of final states including most of the possible two-object combinations of W and Z bosons, photons, Higgs bosons, and gluons place stringent constraints on a variety of theoretical ideas that extend the standard model, pushing into the multi-TeV region the scale of allowed new physics phenomena.

Market-oriented search in differentiated industries

DEFF Research Database (Denmark)

Sørensen, Hans Eibe; Stieglitz, Nils

2009-01-01

  How is the success of a firm's market-oriented activities influenced by the marketing mix? This paper contributes to existing marketing research by advancing our understanding of the process by which market orientation transforms into superior performance. This process is investigated...... on the basis of appropriate organizational search models drawn from the behavioral theory of the firm. Specifically, we draw on the NK model to develop testable propositions that substantiate and extend prior theoretical market orientation research. Our results provide new insight into organizational...... characteristics and consequences of responsive and proactive marketing behaviors, as well as the allocation of attention towards customers and competitors....

Getting satisfied with "satisfaction of search": How to measure errors during multiple-target visual search.

Science.gov (United States)

Biggs, Adam T

2017-07-01

Visual search studies are common in cognitive psychology, and the results generally focus upon accuracy, response times, or both. Most research has focused upon search scenarios where no more than 1 target will be present for any single trial. However, if multiple targets can be present on a single trial, it introduces an additional source of error because the found target can interfere with subsequent search performance. These errors have been studied thoroughly in radiology for decades, although their emphasis in cognitive psychology studies has been more recent. One particular issue with multiple-target search is that these subsequent search errors (i.e., specific errors which occur following a found target) are measured differently by different studies. There is currently no guidance as to which measurement method is best or what impact different measurement methods could have upon various results and conclusions. The current investigation provides two efforts to address these issues. First, the existing literature is reviewed to clarify the appropriate scenarios where subsequent search errors could be observed. Second, several different measurement methods are used with several existing datasets to contrast and compare how each method would have affected the results and conclusions of those studies. The evidence is then used to provide appropriate guidelines for measuring multiple-target search errors in future studies.

SearchResultFinder: federated search made easy

NARCIS (Netherlands)

Trieschnigg, Rudolf Berend; Tjin-Kam-Jet, Kien; Hiemstra, Djoerd

Building a federated search engine based on a large number existing web search engines is a challenge: implementing the programming interface (API) for each search engine is an exacting and time-consuming job. In this demonstration we present SearchResultFinder, a browser plugin which speeds up

Theoretical studies in elementary particle physics

International Nuclear Information System (INIS)

Collins, J.

1994-01-01

This is a report on research conducted at Penn State University under grant number DE-FG02-90ER-40577, from November 1992 to present. The author is a member of the CTEQ collaboration (Coordinated Theoretical and Experimental Project on Quantitative QCD). Some of the work in CTEQ is described in this report. Topics which the authors work has touched include: polarized hard scattering; hard diffraction; small x and perturbative pomeron physics; gauge-invariant operators; fundamental QCD; heavy quarks; instantons and deep inelastic scattering; non-perturbative corrections to τ decay

TMX tandem-mirror experiments and thermal-barrier theoretical studies

International Nuclear Information System (INIS)

Simonen, T.C.; Baldwin, D.E.; Allen, S.L.

1982-01-01

This paper describes recent analysis of energy confinement in the Tandem Mirror Experiment (TMX). TMX data also indicates that warm plasma limits the amplitude of the anisotropy driven Alfven ion cyclotron (AIC) mode. Theoretical calculations show strong AIC stabilization with off-normal beam injection as planned in TMX-U and MFTF-B. This paper reports results of theoretical analysis of hot electrons in thermal barriers including electron heating calculations by Monte Carlo and Fokker-Planck codes and analysis of hot electron MHD and microinstability. Initial results from the TMX-U experiment are presented which show the presence of sloshing ions

Phosphonic drugs: Experimental and theoretical spectroscopic studies of fosfomycin

Science.gov (United States)

Chruszcz-Lipska, Katarzyna; Zborowski, Krzysztof K.; Podstawka-Proniewicz, Edyta; Liu, Shaoxuan; Xu, Yizhuang; Proniewicz, Leonard M.

2011-02-01

pH and time-dependant changes of fosfomycin molecular structure in an aqueous solution are studied by Raman, NMR, and generalized 2D correlation spectroscopies. Interpretation of the experimental spectra is based on the assumption of formation of different species running on applied physicochemical conditions. Geometries of all possible structures were entirely optimized with the 6-311++G(2df,p) basis set at the B3LYP theoretical level using procedures implemented in the Gaussian '03 set of programs. Harmonic frequency calculations verified the nature of the studied structures and allowed to simulate obtained Raman spectra. The theoretical NMR shielding was calculated using the GIAO method at the same computational level. In addition, in some cases PCM model was used to monitor the influence of water molecules on the NMR spectra. It is shown that in the pH range of 1-2 of fosfomycin aqueous solution oxirane ring is open sequent to nucleophilic attack and forms 1,2-dihydroxyphosphonic acid with small content of its monodeprotonated species. On the other hand, in pH 7 and higher it appears either as 1,2-epoxypropylphosphonic or 1,2-dihydroxyphosphonic dianion depending upon whether hydrolysis took place or not. It is also discussed that Raman marker bands originating from the individual species of fosfomycin can be used to detect and/or to monitor this antibiotic in an aqueous medium (for example urine samples). Hence, depending upon the structure found in urine one can tell about metabolic processes of this antibiotic in the body.

A naïve ontology for concepts of time and space for searching and learning

Directory of Open Access Journals (Sweden)

M. Miwa

2007-01-01

Full Text Available Introduction. In this paper, we propose a new approach for developing a naïve ontology as the basis for optimal information access interfaces for multimedia digital documents intended for novice users. Method. We try to elicit the knowledge structure of domain novices and patterns of its modification in their searching and learning processes by eye-tracker and showing eye-movements in the post-search interviews. Analysis. Recorded interview data were fully transcribed and coded using Atlas.ti and analysed following a bottom-up strategy of the constant-comparative technique. Results. We developed a taxonomy of knowledge modification which includes (1 adding, (2 correcting, (3 limiting, (4 relating, (5 specifying and (6 transforming. Conclusion. The taxonomy may be expanded and elaborated as the project progress and findings are expected to be incorporated into the design of the naïve ontology. The study results provided theoretical implications on knowledge building, methodological implications on data collection using eye-tracker and showing eye-movements in the post-search interviews and useful information on the design of information access interface for novices users.

Field Simulation of a Drilling Mission to Mars to Search for Subsurface Life

Science.gov (United States)

Stoker, C. R.; Lemke, L. G.; Cannon, H.; Glass, B.; Dunagan, S.; Zavaleta, J.; Miller, D.; Gomez-Elvira, J.

2005-01-01

The discovery of near surface ground ice by the Mars Odyssey mission and the abundant evidence for recent Gulley features observed by the Mars Global Surveyor mission support longstanding theoretical arguments for subsurface liquid water on Mars. Thus, implementing the Mars program goal to search for life points to drilling on Mars to reach liquid water, collecting samples and analyzing them with instrumentation to detect in situ organisms and biomarker compounds. Searching for life in the subsurface of Mars will require drilling, sample extraction and handling, and new technologies to find and identify biomarker compounds and search for living organisms. In spite of its obvious advantages, robotic drilling for Mars exploration is in its technological infancy and has yet to be demonstrated in even a terrestrial field environment.

How College Students Search the Internet for Weight Control and Weight Management Information: An Observational Study

Science.gov (United States)

Senkowski, Valerie; Branscum, Paul

2015-01-01

Background: Few studies have attempted to examine how young adults search for health information on the Internet, especially information related to weight control and weight management. Purpose: The purpose of this study was to determine search strategies that college students used for finding information related to weight control and weight…

Diphoton measurements with the ATLAS detector at the LHC: search for new resonances and study of diphoton production in association with jets.

CERN Document Server

AUTHOR|(SzGeCERN)735473; Delmastro, Marco

This thesis studies pp collisions at $\\sqrt{s}=8$ TeV with pairs of photons in the final state, as collected by the ATLAS experiment at the LHC during 2012. The diphoton final state has proven to be crucial to the discovery of the Higgs boson. The motivation for searching for additional resonances decaying into two photons is very strong due to many models predicting an extended Higgs sector. At the same time, detailed measurements of diphoton cross sections are necessary to establish the quality of the theoretical predictions currently available for these processes. The measurement of photons by ATLAS relies on an excellent calibration of the electromagnetic calorimeter response. For this reason, studies related to the calibration of the photon response in the ATLAS Liquid Argon (LAr) calorimeter are initially performed, including a measurement of the calorimeter layer energy scale relative calibration using photons, and the potential need of an inter-calibration of the photon energy response as a function ...

An integrated organisation-wide data quality management and information governance framework: theoretical underpinnings.

Science.gov (United States)

Liaw, Siaw-Teng; Pearce, Christopher; Liyanage, Harshana; Liaw, Gladys S S; de Lusignan, Simon

2014-01-01

Increasing investment in eHealth aims to improve cost effectiveness and safety of care. Data extraction and aggregation can create new data products to improve professional practice and provide feedback to improve the quality of source data. A previous systematic review concluded that locally relevant clinical indicators and use of clinical record systems could support clinical governance. We aimed to extend and update the review with a theoretical framework. We searched PubMed, Medline, Web of Science, ABI Inform (Proquest) and Business Source Premier (EBSCO) using the terms curation, information ecosystem, data quality management (DQM), data governance, information governance (IG) and data stewardship. We focused on and analysed the scope of DQM and IG processes, theoretical frameworks, and determinants of the processing, quality assurance, presentation and sharing of data across the enterprise. There are good theoretical reasons for integrated governance, but there is variable alignment of DQM, IG and health system objectives across the health enterprise. Ethical constraints exist that require health information ecosystems to process data in ways that are aligned with improving health and system efficiency and ensuring patient safety. Despite an increasingly 'big-data' environment, DQM and IG in health services are still fragmented across the data production cycle. We extend current work on DQM and IG with a theoretical framework for integrated IG across the data cycle. The dimensions of this theory-based framework would require testing with qualitative and quantitative studies to examine the applicability and utility, along with an evaluation of its impact on data quality across the health enterprise.

Levy-taxis: a novel search strategy for finding odor plumes in turbulent flow-dominated environments

International Nuclear Information System (INIS)

Pasternak, Zohar; Grasso, Frank W; Bartumeus, Frederic

2009-01-01

Locating chemical plumes in aquatic or terrestrial environments is important for many economic, conservation, security and health related human activities. The localization process is composed mainly of two phases: finding the chemical plume and then tracking it to its source. Plume tracking has been the subject of considerable study whereas plume finding has received little attention. We address here the latter issue, where the searching agent must find the plume in a region often many times larger than the plume and devoid of the relevant chemical cues. The probability of detecting the plume not only depends on the movements of the searching agent but also on the fluid mechanical regime, shaping plume intermittency in space and time; this is a basic, general problem when exploring for ephemeral resources (e.g. moving and/or concealing targets). Here we present a bio-inspired search strategy named Levy-taxis that, under certain conditions, located odor plumes significantly faster and with a better success rate than other search strategies such as Levy walks (LW), correlated random walks (CRW) and systematic zig-zag. These results are based on computer simulations which contain, for the first time ever, digitalized real-world water flow and chemical plume instead of their theoretical model approximations. Combining elements of LW and CRW, Levy-taxis is particularly efficient for searching in flow-dominated environments: it adaptively controls the stochastic search pattern using environmental information (i.e. flow) that is available throughout the course of the search and shows correlation with the source providing the cues. This strategy finds natural application in real-world search missions, both by humans and autonomous robots, since it accommodates the stochastic nature of chemical mixing in turbulent flows. In addition, it may prove useful in the field of behavioral ecology, explaining and predicting the movement patterns of various animals searching for food

Levy-taxis: a novel search strategy for finding odor plumes in turbulent flow-dominated environments

Energy Technology Data Exchange (ETDEWEB)

Pasternak, Zohar; Grasso, Frank W [BioMimetic and Cognitive Robotics Laboratory, Department of Psychology, Brooklyn College, The City University of New York, 2900 Bedford Avenue, Brooklyn 11210, NY (United States); Bartumeus, Frederic [Department of Ecology and Evolutionary Biology and Princeton Environmental Institute, 106 Guyot Hall, Princeton University, Princeton 08544, NJ (United States)], E-mail: zpast@yahoo.com

2009-10-30

Locating chemical plumes in aquatic or terrestrial environments is important for many economic, conservation, security and health related human activities. The localization process is composed mainly of two phases: finding the chemical plume and then tracking it to its source. Plume tracking has been the subject of considerable study whereas plume finding has received little attention. We address here the latter issue, where the searching agent must find the plume in a region often many times larger than the plume and devoid of the relevant chemical cues. The probability of detecting the plume not only depends on the movements of the searching agent but also on the fluid mechanical regime, shaping plume intermittency in space and time; this is a basic, general problem when exploring for ephemeral resources (e.g. moving and/or concealing targets). Here we present a bio-inspired search strategy named Levy-taxis that, under certain conditions, located odor plumes significantly faster and with a better success rate than other search strategies such as Levy walks (LW), correlated random walks (CRW) and systematic zig-zag. These results are based on computer simulations which contain, for the first time ever, digitalized real-world water flow and chemical plume instead of their theoretical model approximations. Combining elements of LW and CRW, Levy-taxis is particularly efficient for searching in flow-dominated environments: it adaptively controls the stochastic search pattern using environmental information (i.e. flow) that is available throughout the course of the search and shows correlation with the source providing the cues. This strategy finds natural application in real-world search missions, both by humans and autonomous robots, since it accommodates the stochastic nature of chemical mixing in turbulent flows. In addition, it may prove useful in the field of behavioral ecology, explaining and predicting the movement patterns of various animals searching for food

Mechanical Behaviour of 3D Multi-layer Braided Composites: Experimental, Numerical and Theoretical Study

Science.gov (United States)

Deng, Jian; Zhou, Guangming; Ji, Le; Wang, Xiaopei

2017-12-01

Mechanical properties and failure mechanisms of a newly designed 3D multi-layer braided composites are evaluated by experimental, numerical and theoretical studies. The microstructure of the composites is introduced. The unit cell technique is employed to address the periodic arrangement of the structure. The volume averaging method is used in theoretical solutions while FEM with reasonable periodic boundary conditions and meshing technique in numerical simulations. Experimental studies are also conducted to verify the feasibility of the proposed models. Predicted elastic properties agree well with the experimental data, indicating the feasibility of the proposed models. Numerical evaluation is more accurate than theoretical assessment. Deformations and stress distributions of the unit cell under tension shows displacement and traction continuity, guaranteeing the rationality of the applied periodic boundary conditions. Although compression and tension modulus are close, the compressive strength only reaches 70% of the tension strength. This indicates that the composites can be weakened in compressive loading. Additionally, by analysing the micrograph of fracture faces and strain-stress curves, a brittle failure mechanism is observed both in composites under tension and compression.

Theoretical Issues and Methodological Implications in Researching Visual Search Behaviours: A Preliminary Study Comparing the Cognitive and Ecologic Paradigms

Directory of Open Access Journals (Sweden)

José Afonso

2013-09-01

Full Text Available A number of research papers have been devoted to understanding the mechanisms underpinning successful decision-making in sports, and analysis of eye movements has deserved special attention in this concern. A thorough reading of existing literature denotes that research on ocular fixations requires at least 100 milliseconds within the same location. For average eye-tracking systems, this means using at least three frames for each fixation. However, ecological psychology has claimed that as low as 16.67 milliseconds might suffice to capture relevant information, implying using merely one frame to consider that a fixation has been made. The goal of this experiment was to directly compare two systems (one frame-one fixation versus three frames-one fixation for coding information concerning eye movements in a representative volleyball task in an in situ condition. Specifically, it was intended to analyse emerging differences and their meaning. Results exhibited statistically significant differences with regard to search rate (number of fixations, number of fixation locations, and mean fixation duration. Analysing fixation locations it was apparent that the ecological paradigm for considering visual fixations afforded supplementary information. Furthermore, the additional emerging cues appeared to be meaningful, and the level of noise introduced was very low. It is suggested that future research in eye movements considers using the one frame-one fixation approach, instead of the traditional three frames-one fixation set.

'Alive' searches as complementing death searches in the epidemiological follow-up of Ontario miners

International Nuclear Information System (INIS)

Fair, M.E.; Newcombe, H.B.; Lalonde, P.; Poliquin, C.

1988-02-01

'Alive' searches have been used to complement the 'death' searches, in a study of the mortality experience of a cohort of Ontario miners. The purpose has been to develop a way of distinguishing between those cohort members who are 'confirmed' alive at a given time, and those who are 'lost to follow-up'. A total of 30,000 Workers' Compensation Board (WCB) records with valid Social Insurance Numbers (SIN) were used to search the income tax files by computer over two consecutive years (1977 and 1978) representing nearly 27 million tax returns. These tax file searches using SIN numbers have provided information on the procedures to be used in, and likely success of, the corresponding searches of the tax files that could be carried out where the SIN number is not available on the work records. The latter kind of search would have to be based on names, birth dates and such, and would be probabilistic in nature. The results of the study were as follows: After the initial death search, it was found that 7.5% of the cohort had died in Canada and their records were found on the Mortality Data Base. The remaining 92.5% has been 'assumed alive' in the earlier analysis. After the 'alive' follow-up using the income tax file, one was able to confirm that 89.1% of the 'assumed alive' had filed an income tax after the study period. Thus only 3.4% of the cohort remained untraced. Among those there could be an admixture of deaths outside of Canada, persons who have moved outside of Canada and are still alive, and/or persons alive within Canada, but who have not filed an income tax return. This study has indicated that the procedures developed are useful for purposes of 'alive' follow-up, for evaluation of the quality of the Mortality Data Base-cohort death file searches, for improving the accuracy of analytical results of epidemiological studies, and for reducing the cost and labour of resolving doubtful death searches

Effects of lattice parameters on piezoelectric constants in wurtzite materials: A theoretical study using first-principles and statistical-learning methods

Science.gov (United States)

Momida, Hiroyoshi; Oguchi, Tamio

2018-04-01

Longitudinal piezoelectric constant (e 33) values of wurtzite materials, which are listed in a structure database, are calculated and analyzed by using first-principles and statistical learning methods. It is theoretically shown that wurtzite materials with high e 33 generally have small lattice constant ratios (c/a) almost independent of constituent elements, and approximately expressed as e 33 ∝ c/a - (c/a)0 with ideal lattice constant ratio (c/a)0. This relation also holds for highly-piezoelectric ternary materials such as Sc x Al1- x N. We conducted a search for high-piezoelectric wurtzite materials by identifying materials with smaller c/a values. It is proposed that the piezoelectricity of ZnO can be significantly enhanced by substitutions of Zn with Ca.

The Searching Behavior of Remote Users: A Study of One Online Public Access Catalog (OPAC).

Science.gov (United States)

Kalin, Sally W.

1991-01-01

Describes a study that was conducted to determine whether the searching behavior of remote users of LIAS (Library Information Access System), Pennsylvania State University's online public access catalog (OPAC), differed from those using the OPAC within the library. Differences in search strategies and in user satisfaction are discussed. (eight…

Theoretical and experimental NMR studies on muscimol from fly agaric mushroom (Amanita muscaria)

Science.gov (United States)

Kupka, Teobald; Wieczorek, Piotr P.

2016-01-01

In this article we report results of combined theoretical and experimental NMR studies on muscimol, the bioactive alkaloid from fly agaric mushroom (Amanita muscaria). The assignment of 1H and 13C NMR spectra of muscimol in DMSO-d6 was supported by additional two-dimensional heteronuclear correlated spectra (2D NMR) and gauge independent atomic orbital (GIAO) NMR calculations using density functional theory (DFT). The effect of solvent in theoretical calculations was included via polarized continuum model (PCM) and the hybrid three-parameter B3LYP density functional in combination with 6-311++G(3df,2pd) basis set enabled calculation of reliable structures of non-ionized (neutral) molecule and its NH and zwitterionic forms in the gas phase, chloroform, DMSO and water. GIAO NMR calculations, using equilibrium and rovibrationally averaged geometry, at B3LYP/6-31G* and B3LYP/aug-cc-pVTZ-J levels of theory provided muscimol nuclear magnetic shieldings. The theoretical proton and carbon chemical shifts were critically compared with experimental NMR spectra measured in DMSO. Our results provide useful information on its structure in solution. We believe that such data could improve the understanding of basic features of muscimol at atomistic level and provide another tool in studies related to GABA analogs.

A Theoretical Framework for Studying Adolescent Contraceptive Use.

Science.gov (United States)

Urberg, Kathryn A.

1982-01-01

Presents a theoretical framework for viewing adolescent contraceptive usage. The problem-solving process is used for developmentally examining the competencies that must be present for effective contraceptive use, including: problem recognition, motivation, generation of alternatives, decision making and implementation. Each aspect is discussed…

Search for electroweak production of supersymmetric gauginos with photons at CMS

CERN Document Server

Schulz, Johannes

2014-01-01

In this thesis a search for electroweak production of gauginos in the theoretical context of gaugemediated supersymmetry is presented. Under the assumption of a bino-like mixture of the gaugeeigenstates of the lightest neutralino, being the next-to-lightest supersymmetric particle in thisanalysis, decays of the lightest neutralino into a photon and a gravitino are highly preferred. Dueto R-parity conservation, the gravitino is stable. Since it does not interact with the detector, anincreased amount of missing transverse energy is expected in the event. The search is performedusing a parked dataset corresponding to an integrated luminosity of 7.4 fb−1 , recorded by theCMS detector during the proton-proton collisions at the LHC in 2012. The search strategy isfocused on selecting high energetic photons accompanied by significantly high genuine missingtransverse energy. Due to the focus on electroweak production, the event selection favors finalstates with a moderate amount of hadronic activity, complementing...

A search for R-parity violating single sneutrino production at LEPII

International Nuclear Information System (INIS)

Coles, J.

2000-01-01

Supersymmetry has become one of the most accepted and theoretically interesting extensions to the Standard Model of particle physics, yet it has so far eluded discovery. For this reason there is a large amount of interest in direct particle searches looking for evidence of either R-parity conserving or R-parity violating signatures at high-energy colliders such as LEP. This work sets out to describe one such search, that for the R-parity violating process of resonant single sneutrino production. The R-parity violating searches are performed on ALEPH data taken at centre-of-mass energies 130 to 189 GeV. As no evidence for a signal is found, limits are set within the framework of a minimal supergravity model. The best upper limits obtained for the LLE-bar couplings λ 121 and λ 131 are shown to be better than 5 x 10 -4 at 95% C.L. These results provide a substantial improvement over existing low energy bounds. (author)

Search for second generation scalar leptoquarks using the ATLAS detector

Energy Technology Data Exchange (ETDEWEB)

Tam, Jason

2014-07-24

Leptoquarks are hypothetical particles that attempt to explain the coincidental similarities between leptons and quarks included in SM. Their exact properties vary between different theoretical models, and there are no strong theoretical constraints on their possible mass values. They can possibly be produced from particle collisions, and there have already been searching efforts at previous collider experiments. Their presence have not yet been observed, and this fact has been translated into lower bound exclusions on their possible mass values. The Large Hadron Collider (LHC) being the most recently constructed particle collider with the highest collision energies ever achieved experimentally, provides a new platform to continue the search for Leptoquarks at even higher mass ranges. This thesis describes a search for pair-produced second-generation Leptoquarks using 20.3 fb{sup -1} of data recorded by the ATLAS detector of LHC at √(s) = 8 TeV. Events with two oppositely charged muons and two or more jets in the final state were used. Candidate leptoquark events were selected with the help of four observables: the di-muon invariant mass (M{sub μμ}), the sum of the p{sub T} of the two muons (L{sub T}), the sum of the p{sub T} of the two leading jets (H{sub T}) and the average Leptoquark mass (M{sub LQ}). Monte Carlo simulations of SM background processes have shown to be in good agreement with data, both in the region constructed using selection requirements for candidate leptoquark events and in the designated control regions. Since no significant excess of events was observed in data, a exclusion limit was set as a function of the Leptoquark mass.

Set-theoretic methods in control

CERN Document Server

Blanchini, Franco

2015-01-01

The second edition of this monograph describes the set-theoretic approach for the control and analysis of dynamic systems, both from a theoretical and practical standpoint.  This approach is linked to fundamental control problems, such as Lyapunov stability analysis and stabilization, optimal control, control under constraints, persistent disturbance rejection, and uncertain systems analysis and synthesis.  Completely self-contained, this book provides a solid foundation of mathematical techniques and applications, extensive references to the relevant literature, and numerous avenues for further theoretical study. All the material from the first edition has been updated to reflect the most recent developments in the field, and a new chapter on switching systems has been added.  Each chapter contains examples, case studies, and exercises to allow for a better understanding of theoretical concepts by practical application. The mathematical language is kept to the minimum level necessary for the adequate for...

Federated Search and the Library Web Site: A Study of Association of Research Libraries Member Web Sites

Science.gov (United States)

Williams, Sarah C.

2010-01-01

The purpose of this study was to investigate how federated search engines are incorporated into the Web sites of libraries in the Association of Research Libraries. In 2009, information was gathered for each library in the Association of Research Libraries with a federated search engine. This included the name of the federated search service and…

Optimizing literature search in systematic reviews

DEFF Research Database (Denmark)

Aagaard, Thomas; Lund, Hans; Juhl, Carsten Bogh

2016-01-01

BACKGROUND: When conducting systematic reviews, it is essential to perform a comprehensive literature search to identify all published studies relevant to the specific research question. The Cochrane Collaborations Methodological Expectations of Cochrane Intervention Reviews (MECIR) guidelines...... of musculoskeletal disorders. METHODS: Data sources were systematic reviews published by the Cochrane Musculoskeletal Review Group, including at least five RCTs, reporting a search history, searching MEDLINE, EMBASE, CENTRAL, and adding reference- and hand-searching. Additional databases were deemed eligible...... if they indexed RCTs, were in English and used in more than three of the systematic reviews. Relative recall was calculated as the number of studies identified by the literature search divided by the number of eligible studies i.e. included studies in the individual systematic reviews. Finally, cumulative median...

Theoretical physics division

International Nuclear Information System (INIS)

Anon.

The studies in 1977 are reviewed. In theoretical nuclear physics: nuclear structure, nuclear reactions, intermediate energy physics; in elementary particle physics: field theory, strong interactions dynamics, nucleon-nucleon interactions, new particles, current algebra, symmetries and quarks are studied [fr

Adsorption of uranium composites onto saltrock oxides - experimental and theoretical study.

Science.gov (United States)

Ivanova, Bojidarka; Spiteller, Michael

2014-09-01

The study encompassed experimental mass spectrometric and theoretical quantum chemical studies on adsorption of uranium species in different oxidation states of the metal ion, and oxides of UxOy(n+) type, where x = 1 or 3, y = 2 or 8, and n = 0, 1 or 2 onto nanosize-particles of saltrock oxides MO (M = Mg(II), Ca(II), Ni(II), Co(II), Sr(II) or Ba(II)), M2Oy (M = Au(III) or Ag(I), y = 3 or 1) silicates 3Al2O3.2SiO2, natural kaolinite (Al2O2·2SiO2·2H2O), illite (K0.78Ca0.02Na0.02(Mg0.34Al1.69Fe(III)0.02)[Si3.35Al0.65]O10(OH)2·nH2O), CaSiO3, 3MgO·4SiO2,H2O, and M(1)M(2)(SiO4)X2 (M(1) = M(2) = Al or M(1) = K, M(2) = Al, X = F or Cl), respectively. The UV-MALDI-Orbitrap mass spectrometry was utilized in solid-state and semi-liquid colloidal state, involving the laser ablation at λex = 337.2 nm. The theoretical modeling and experimental design was based on chemical-, physico-chemical, physical and biological processes involving uranium species under environmental conditions. Therefore, the results reported are crucial for quality control and monitoring programs for assessment of radionuclide migration. They impact significantly the methodology for evaluation of human health risk from radioactive contamination. The study has importance for understanding the coordination and red-ox chemistry of uranium compounds as well. Due to the double nature of uranium between rare element and superconductivity like materials as well as variety of oxidation states ∈ (+1)-(+6), the there remain challenging areas for theoretical and experimental research, which are of significant importance for management of nuclear fuel cycles and waste storage. Copyright © 2014 Elsevier Ltd. All rights reserved.

Using Mathematics, Mathematical Applications, Mathematical Modelling, and Mathematical Literacy: A Theoretical Study

Science.gov (United States)

Mumcu, Hayal Yavuz

2016-01-01

The purpose of this theoretical study is to explore the relationships between the concepts of using mathematics in the daily life, mathematical applications, mathematical modelling, and mathematical literacy. As these concepts are generally taken as independent concepts in the related literature, they are confused with each other and it becomes…

Searching for Suicide Information on Web Search Engines in Chinese

Directory of Open Access Journals (Sweden)

Yen-Feng Lee

2017-01-01

Full Text Available Introduction: Recently, suicide prevention has been an important public health issue. However, with the growing access to information in cyberspace, the harmful information is easily accessible online. To investigate the accessibility of potentially harmful suicide-related information on the internet, we discuss the following issue about searching suicide information on the internet to draw attention to it. Methods: We use five search engines (Google, Yahoo, Bing, Yam, and Sina and four suicide-related search queries (suicide, how to suicide, suicide methods, and want to die in traditional Chinese in April 2016. We classified the first thirty linkages of the search results on each search engine by a psychiatric doctor into suicide prevention, pro-suicide, neutral, unrelated to suicide, or error websites. Results: Among the total 352 unique websites generated, the suicide prevention websites were the most frequent among the search results (37.8%, followed by websites unrelated to suicide (25.9% and neutral websites (23.0%. However, pro-suicide websites were still easily accessible (9.7%. Besides, compared with the USA and China, the search engine originating in Taiwan had the lowest accessibility to pro-suicide information. The results of ANOVA showed a significant difference between the groups, F = 8.772, P < 0.001. Conclusions: This study results suggest a need for further restrictions and regulations of pro-suicide information on the internet. Providing more supportive information online may be an effective plan for suicidal prevention.

H → γγ search and direct photon pair production differential cross section

International Nuclear Information System (INIS)

Bu, Xuebing

2010-01-01

At a hadron collider, diphoton (γγ) production allows detailed studies of the Standard Model (SM), as well as as searches for new phenomena, such as new heavy resonances, extra spatial dimensions or cascade decays of heavy new particles. Within the SM, continuum γγ+X production is characterized by a steeply-falling γγ mass spectrum, on top of which a heavy resonance decaying into γγ can potentially be observed. In particular, this is considered one of the most promising discovery channels for a SM Higgs boson at the LHC, despite the small branching ratio of BR (H → γγ) ∼ 0.2% for 110 Higgs -1 of the D0 Run II data, collected at the Fermilab Tevatron collider from April 2002 to December 2008. Good agreement between the data and the SM background prediction is observed. Since there is no evidence for new physics, we set 95% C.L. limits on the production cross section times the branching ratio (σ x BR(H → γγ)) relative to the SM-like Higgs prediction for different assumed Higgs masses. The observed limits (σ(limit)/σ(SM)) range from 11.9 to 35.2 for Higgs masses from 100 to 150 GeV, while the expected limits range from 17.5 to 32.0. This search is also interpreted in the context of the particular fermiophobic Higgs model. The corresponding results have reached the same sensitivity as a single LEP experiement, setting a lower limit on the fermiophobic Higgs of M h# sub f# > 102.5 GeV (M h# sub f# > 107.5 GeV expected). We are slightly below the combined LEP limit (M h# sub f# > 109.7 GeV). We also provide access to the M h# sub f# > 125 GeV region which was inaccessible at LEP. During the study, we found the major and irreducible background direct γγ (DPP) production is not well modelled by the current theoretical predictions: RESBOS, DIPHOX or PYTHIA. There is ∼20% theoretical uncertainty for the predicted values. Thus, for our Higgs search, we use the side-band fitting method to estimate DPP contribution directly from the data events

Mars Analog Rio Tinto Experiment (MARTE): An Experimental Demonstration of Key Technologies for Searching for Life on Mars

Science.gov (United States)

Stoker, Carol

2004-01-01

The discovery of near surface ground ice by the Mars Odyssey mission and the abundant evidence for recent Gulley features observed by the Mars Global Surveyor mission support longstanding theoretical arguments for subsurface liquid water on Mars. Thus, implementing the Mars program goal to search for life points to drilling on Mars to reach liquid water, collecting samples and analyzing them with instrumentation to detect in situ organisms and biomarker compounds. Searching for life in the subsurface of Mars will require drilling, sample extraction and handling, and new technologies to find and identify biomarker compounds and search for living organisms.

Studies of the tautomeric equilibrium of 1,3-thiazolidine-2-thione: Theoretical and experimental approaches

Energy Technology Data Exchange (ETDEWEB)

Abbehausen, Camilla; Paiva, Raphael E.F. de [Institute of Chemistry, University of Campinas - UNICAMP, P.O. Box 6154, 13083-970 Campinas, SP (Brazil); Formiga, Andre L.B., E-mail: formiga@iqm.unicamp.br [Institute of Chemistry, University of Campinas - UNICAMP, P.O. Box 6154, 13083-970 Campinas, SP (Brazil); Corbi, Pedro P. [Institute of Chemistry, University of Campinas - UNICAMP, P.O. Box 6154, 13083-970 Campinas, SP (Brazil)

2012-10-26

Highlights: Black-Right-Pointing-Pointer Tautomeric equilibrium in solution. Black-Right-Pointing-Pointer Spectroscopic and theoretical studies. Black-Right-Pointing-Pointer UV-Vis theoretical and experimental spectra. Black-Right-Pointing-Pointer {sup 1}H NMR theoretical and experimental spectra. -- Abstract: The tautomeric equilibrium of the thione/thiol forms of 1,3-thiazolidine-2-thione was studied by nuclear magnetic resonance, infrared and ultraviolet-visible spectroscopies. Density functional theory was used to support the experimental data and indicates the predominance of the thione tautomer in the solid state, being in agreement with previously reported crystallographic data. In solution, the tautomeric equilibrium was evaluated using {sup 1}H NMR at different temperatures in four deuterated solvents acetonitrile, dimethylsulfoxide, chloroform and methanol. The equilibrium constants, K = (thiol)/(thione), and free Gibbs energies were obtained by integration of N bonded hydrogen signals at each temperature for each solvent, excluding methanol. The endothermic tautomerization is entropy-driven and the combined effect of solvent and temperature can be used to achieve almost 50% thiol concentrations in solution. The nature of the electronic transitions was investigated theoretically and the assignment of the bands was made using time-dependent DFT as well as the influence of solvent on the energy of the most important bands of the spectra.

Study of network resource allocation based on market and game theoretic mechanism

Science.gov (United States)

Liu, Yingmei; Wang, Hongwei; Wang, Gang

2004-04-01

We work on the network resource allocation issue concerning network management system function based on market-oriented mechanism. The scheme is to model the telecommunication network resources as trading goods in which the various network components could be owned by different competitive, real-world entities. This is a multidisciplinary framework concentrating on the similarity between resource allocation in network environment and the market mechanism in economic theory. By taking an economic (market-based and game theoretic) approach in routing of communication network, we study the dynamic behavior under game-theoretic framework in allocating network resources. Based on the prior work of Gibney and Jennings, we apply concepts of utility and fitness to the market mechanism with an intention to close the gap between experiment environment and real world situation.

Exploratory experimental and theoretical studies of cyclone gasification of wood powder

Energy Technology Data Exchange (ETDEWEB)

Fredriksson, Christian

1999-11-01

This thesis describes an exploratory experimental and theoretical study of gasification of wood powder in a cyclone gasifier. The generated gas could be used to operate a gas turbine in a combined cycle power plant. The objective has been to develop the understanding of cyclone gasification by experimental studies of the performance of a cyclone designed in principle as a separation cyclone and by comparisons between the experimental results and theoretical predictions. The experiments were carried out with commercial Swedish wood powder fuels, injected with air or steam/air mixture through two diametrically opposite tangential inlets and gasified at atmospheric pressure in cyclones of two different configurations with a volume of about 0.034 m{sup 3}. The studies show that stable gasification of this fuel can be obtained for a specific fuel feeding rate of about 5 MW/m{sup 3} cyclone volume for equivalence ratios above 0.15 and that the equivalence ratio had to be kept below about 0.4 in order to avoid material temperatures above 950 deg C. A cyclone with a short outlet pipe, designed as a conventional separation cyclone was found to give lower char conversion than a modified cyclone with a long outlet pipe. The heating value of the gas was found to be approximately 4.5 MJ/kg. The dust load in the product gas was measured to between 1000 and 2500 mg/Nm{sup 3}. It was possible to separate at least 40-60% of the potassium and 60-90% of the sodium supplied with the wood. The alkali that left the cyclone with the product gas appear to be in solid or melted phase in the unseparated char particles and consequently not vaporised during gasification. As the K and Na were assumed to remain within the particles during gasification, it was concluded that to reduce the amount of alkali metals in the product gas it would be necessary to improve the particle separation efficiency. The results of the theoretical modelling, using the existing models in the commercial software CFX

Theoretical Study of Irradiation Effects in Close Binaries

Directory of Open Access Journals (Sweden)

Srinivasa Rao, M.

2009-06-01

Full Text Available The effect of irradiation is studied in a close binary systemassuming that the secondary component is a point source, moving in a circularorbit. The irradiation effects are calculatedon the atmosphere of the primary component in a 3-dimensional Cartesiancoordinate geometry. In treating the reflection effect theoretically, the totalradiation $(S_mathrm{T}$ is obtained as the sum of the radiation of 1 the effect ofirradiation on the primary component which is calculated by using onedimensional rod model $(S_mathrm{r}$ and 2 the self radiation of the primarycomponent which is calculated by using the solution of radiative transferequation in spherical symmetry $(S_mathrm{s}$. The radiation field is estimated alongthe line of sight of the observer at infinity. It is shown how the radiationfield changes depending on the position of the secondary component.

Theoretical study of the ionization of B2H5

International Nuclear Information System (INIS)

Curtiss, L.A.; Pople, J.A.

1989-01-01

Ab initio molecular orbital calculations at the G1 level of theory have been carried out on neutral B 2 H 5 radical, doubly bridged B 2 H + 5 cation, and the first triplet excited state of B 2 H + 5 . Singly bridged B 2 H 5 is 4.0 kcal/mol (without zero-point energies) more stable than doubly bridged B 2 H 5 . Based on this work and previous theoretical work on triply bridged B 2 H + 5 , ionization potentials (vertical and adiabatic) are determined for B 2 H 5 . The adiabatic ionization potentials of the two B 2 H 5 structures are 6.94 eV (singly bridged) and 7.53 eV (doubly bridged). A very large difference is found between the vertical and adiabatic ionization potentials (3.37 eV) of the singly bridged B 2 H 5 structure. The first triplet state of B 2 H + 5 is found to be 4.55 eV higher in energy than the lowest energy B 2 H + 5 cation (triply bridged). The results of this theoretical study support the interpretation of Ruscic, Schwarz, and Berkowitz of their recent photoionization measurements on B 2 H 5

Theoretical study of defect properties in metals

International Nuclear Information System (INIS)

Sindzingre, P.

1987-01-01

Several characteristic properties (formation and migration enthalpies and volumes, dipole tensors, effects on shear elastic constants) of several point defects (vacancy, divacancy, interstitial, di-interstitial) in different metals: f.c.c. metals (Al, Cu, Ag, Au), h.c.p. metals (Be, Mg, Zn, Cd, Na, Co, Ti, Zr), b.c.c. metals (Li, Na, K, Rb, Cs) have been calculated. The calculated properties are evaluated from static computations performed with pair potentials derived from pseudo-potential theory (for simple or noble metals) or deduced empirically. Results are compared with available experimental data with previous theoretical works. The first part of this work where we have studied point defects properties in f.c.c. metals lead us to suggest a more convincing interpretation of X-ray scattering and elastic relation measurements concerning interstitials in Al and Cu, and a new interpretation for X-ray scattering measurements concerning di-interstitials in Al. In the second part, devoted to h.c.p. metals we are brought to propose for each studied metal the interstitial configurations which yield the best agreement with experimental results. The third part, devoted to the study of point defects in alkalin b.c.c. metals lead us to interpret self-diffusion in these metals with the assumption of a simultaneous contribution of monovacancies, divacancies and interstitials [fr

Generalised Adaptive Harmony Search: A Comparative Analysis of Modern Harmony Search

Directory of Open Access Journals (Sweden)

Jaco Fourie

2013-01-01

Full Text Available Harmony search (HS was introduced in 2001 as a heuristic population-based optimisation algorithm. Since then HS has become a popular alternative to other heuristic algorithms like simulated annealing and particle swarm optimisation. However, some flaws, like the need for parameter tuning, were identified and have been a topic of study for much research over the last 10 years. Many variants of HS were developed to address some of these flaws, and most of them have made substantial improvements. In this paper we compare the performance of three recent HS variants: exploratory harmony search, self-adaptive harmony search, and dynamic local-best harmony search. We compare the accuracy of these algorithms, using a set of well-known optimisation benchmark functions that include both unimodal and multimodal problems. Observations from this comparison led us to design a novel hybrid that combines the best attributes of these modern variants into a single optimiser called generalised adaptive harmony search.

Impact of Internet Search Engines on OPAC Users: A Study of Punjabi University, Patiala (India)

Science.gov (United States)

Kumar, Shiv

2012-01-01

Purpose: The aim of this paper is to study the impact of internet search engine usage with special reference to OPAC searches in the Punjabi University Library, Patiala, Punjab (India). Design/methodology/approach: The primary data were collected from 352 users comprising faculty, research scholars and postgraduate students of the university. A…

Theoretical study on the ultra-narrow bandwidth tunable atomic filter with electromagnetically induced transparency

Science.gov (United States)

Liu, Yang; Li, Shu-qing; Feng, Zhong-ying; Liu, Xiao-fei; Gao, Jin-yue

2016-12-01

To obtain the weak signal light detection from the high background noise, we present a theoretical study on the ultra-narrow bandwidth tunable atomic filter with electromagnetically induced transparency. In a three-level Λ -type atomic system in the rubidium D1 line, the bandwidth of the EIT atomic filter is narrowed to ~6.5 \\text{MHz} . And the single peak transmission of the filter can be up to 86% . Moreover, the transmission wavelength can be tuned by changing the coupling light frequency. This theoretical scheme can also be applied to other alkali atomic systems.

Galactic searches for dark matter

International Nuclear Information System (INIS)

Strigari, Louis E.

2013-01-01

For nearly a century, more mass has been measured in galaxies than is contained in the luminous stars and gas. Through continual advances in observations and theory, it has become clear that the dark matter in galaxies is not comprised of known astronomical objects or baryonic matter, and that identification of it is certain to reveal a profound connection between astrophysics, cosmology, and fundamental physics. The best explanation for dark matter is that it is in the form of a yet undiscovered particle of nature, with experiments now gaining sensitivity to the most well-motivated particle dark matter candidates. In this article, I review measurements of dark matter in the Milky Way and its satellite galaxies and the status of Galactic searches for particle dark matter using a combination of terrestrial and space-based astroparticle detectors, and large scale astronomical surveys. I review the limits on the dark matter annihilation and scattering cross sections that can be extracted from both astroparticle experiments and astronomical observations, and explore the theoretical implications of these limits. I discuss methods to measure the properties of particle dark matter using future experiments, and conclude by highlighting the exciting potential for dark matter searches during the next decade, and beyond

Proposal to Search for Heavy Neutral Leptons at the SPS

CERN Document Server

Bonivento, W.; Dijkstra, H.; Egede, U.; Ferro-Luzzi, M.; Goddard, B.; Golutvin, A.; Gorbunov, D.; Jacobsson, R.; Panman, J.; Patel, M.; Ruchayskiy, O.; Ruf, T.; Serra, N.; Shaposhnikov, M.; Treille, D.; CERN. Geneva. SPS and PS Experiments Committee; SPSC

2013-01-01

A new fixed-target experiment at the CERN SPS accelerator is proposed that will use decays of charm mesons to search for Heavy Neutral Leptons (HNLs), which are right-handed partners of the Standard Model neutrinos. The existence of such particles is strongly motivated by theory, as they can simultaneously explain the baryon asymmetry of the Universe, account for the pattern of neutrino masses and oscillations and provide a Dark Matter candidate. Cosmological constraints on the properties of HNLs now indicate that the majority of the interesting parameter space for such particles was beyond the reach of the previous searches at the PS191, BEBC, CHARM, CCFR and NuTeV experiments. For HNLs with mass below 2 GeV, the proposed experiment will improve on the sensitivity of previous searches by four orders of magnitude and will cover a major fraction of the parameter space favoured by theoretical models. The experiment requires a 400 GeV proton beam from the SPS with a total of 2x10^20 protons on target, achie...

Theoretical study of diaquamalonatozinc(II) single crystal for ...

Indian Academy of Sciences (India)

MITESH CHAKRABORTY

2017-11-28

Nov 28, 2017 ... 2Laser and Spectroscopy Laboratory, Department of Applied Physics, Indian Institute of ... The aim of the present paper is to employ theoretical methods to investigate the zero field splitting .... using quantum chemistry computational models has ..... The authors are grateful to the Science and Engineer-.

Confirmation bias in web-based search: a randomized online study on the effects of expert information and social tags on information search and evaluation.

Science.gov (United States)

Schweiger, Stefan; Oeberst, Aileen; Cress, Ulrike

2014-03-26

The public typically believes psychotherapy to be more effective than pharmacotherapy for depression treatments. This is not consistent with current scientific evidence, which shows that both types of treatment are about equally effective. The study investigates whether this bias towards psychotherapy guides online information search and whether the bias can be reduced by explicitly providing expert information (in a blog entry) and by providing tag clouds that implicitly reveal experts' evaluations. A total of 174 participants completed a fully automated Web-based study after we invited them via mailing lists. First, participants read two blog posts by experts that either challenged or supported the bias towards psychotherapy. Subsequently, participants searched for information about depression treatment in an online environment that provided more experts' blog posts about the effectiveness of treatments based on alleged research findings. These blogs were organized in a tag cloud; both psychotherapy tags and pharmacotherapy tags were popular. We measured tag and blog post selection, efficacy ratings of the presented treatments, and participants' treatment recommendation after information search. Participants demonstrated a clear bias towards psychotherapy (mean 4.53, SD 1.99) compared to pharmacotherapy (mean 2.73, SD 2.41; t173=7.67, Pinformation search and evaluation. This bias was significantly reduced, however, when participants were exposed to tag clouds with challenging popular tags. Participants facing popular tags challenging their bias (n=61) showed significantly less biased tag selection (F2,168=10.61, Pinformation as presented in blog posts, compared to supporting expert information (n=81), decreased the bias in information search with regard to blog post selection (F1,168=4.32, P=.04, partial eta squared=0.025). No significant effects were found for treatment recommendation (Ps>.33). We conclude that the psychotherapy bias is most effectively

Theoretical expectations for the muon's electric dipole moment

International Nuclear Information System (INIS)

Feng, Jonathan L.; Matchev, Konstantin T.; Shadmi, Yael

2001-01-01

We examine the muon's electric dipole moment d μ from a variety of theoretical perspectives. We point out that the reported deviation in the muon's g-2 can be due partially or even entirely to a new physics contribution to the muon's electric dipole moment. In fact, the recent g-2 measurement provides the most stringent bound on d μ to date. This ambiguity could be definitively resolved by the dedicated search for d μ recently proposed. We then consider both model-independent and supersymmetric frameworks. Under the assumptions of scalar degeneracy, proportionality, and flavor conservation, the theoretical expectations for d μ in supersymmetry fall just below the proposed sensitivity. However, nondegeneracy can give an order of magnitude enhancement, and lepton flavor violation can lead to d μ ∼10 -22 e cm, two orders of magnitude above the sensitivity of the d μ experiment. We present compact expressions for leptonic dipole moments and lepton flavor violating amplitudes. We also derive new limits on the amount of flavor violation allowed and demonstrate that approximations previously used to obtain such limits are highly inaccurate in much of parameter space

Information-seeking behavior during residency is associated with quality of theoretical learning, academic career achievements, and evidence-based medical practice: a strobe-compliant article.

Science.gov (United States)

Oussalah, Abderrahim; Fournier, Jean-Paul; Guéant, Jean-Louis; Braun, Marc

2015-02-01

Data regarding knowledge acquisition during residency training are sparse. Predictors of theoretical learning quality, academic career achievements and evidence-based medical practice during residency are unknown. We performed a cross-sectional study on residents and attending physicians across several residency programs in 2 French faculties of medicine. We comprehensively evaluated the information-seeking behavior (I-SB) during residency using a standardized questionnaire and looked for independent predictors of theoretical learning quality, academic career achievements, and evidence-based medical practice among I-SB components using multivariate logistic regression analysis. Between February 2013 and May 2013, 338 fellows and attending physicians were included in the study. Textbooks and international medical journals were reported to be used on a regular basis by 24% and 57% of the respondents, respectively. Among the respondents, 47% refer systematically (4.4%) or frequently (42.6%) to published guidelines from scientific societies upon their publication. The median self-reported theoretical learning quality score was 5/10 (interquartile range, 3-6; range, 1-10). A high theoretical learning quality score (upper quartile) was independently and strongly associated with the following I-SB components: systematic reading of clinical guidelines upon their publication (odds ratio [OR], 5.55; 95% confidence interval [CI], 1.77-17.44); having access to a library that offers the leading textbooks of the specialty in the medical department (OR, 2.45, 95% CI, 1.33-4.52); knowledge of the specialty leading textbooks (OR, 2.12; 95% CI, 1.09-4.10); and PubMed search skill score ≥5/10 (OR, 1.94; 95% CI, 1.01-3.73). Research Master (M2) and/or PhD thesis enrolment were independently and strongly associated with the following predictors: PubMed search skill score ≥5/10 (OR, 4.10; 95% CI, 1.46-11.53); knowledge of the leading medical journals of the specialty (OR, 3.33; 95

Double beta decay searches of 134Xe, 126Xe and 124Xe with large scale Xe detectors

International Nuclear Information System (INIS)

Barros, N; Thurn, J; Zuber, K

2014-01-01

The sensitivity for double beta decay studies of 134 Xe and 124 Xe is investigated assuming a potential large scale Xe experiment developed for dark matter searches depleted in 136 Xe. The opportunity for an observation of the 2νββ - decay of 134 Xe is explored for various scenarios. A positive observation should be possible for all calculated nuclear matrix elements. The detection of 2ν ECEC of 124 Xe can be probed in all scenarios covering the theoretical predicted half-life uncertainties and a potential search for 126 Xe is discussed. The sensitivity to β + EC decay of 124 Xe is discussed and a positive observation might be possible, while β + β + decay still remains unobservable. The performed studies take into account solar pp–neutrino interactions, 85 Kr beta decay and remaining 136 Xe double beta decay as background components in the depleted detector. (paper)

Theoretical and Experimental Study on Electromechanical Coupling Properties of Multihammer Synchronous Vibration System

Directory of Open Access Journals (Sweden)

Xin Lai

2016-01-01

Full Text Available Industrial simulation of real external load using multiple exciting points or increasing exciting force by synchronizing multiple exciting forces requires multiple vibration hammers to be coordinated and work together. Multihammer vibration system which consists of several hammers is a complex electromechanical system with complex electromechanical coupling. In this paper, electromechanical coupling properties of such a multihammer vibration system were studied in detail using theoretical derivation, numerical simulation, and experiment. A kinetic model of multihammer synchronous vibration system was established, and approximate expressions for electromechanical coupling strength were solved using a small parameter periodic averaging method. Basic coupling rules and reasons were obtained. Self-synchronization and frequency hopping phenomenon were also analyzed. Subsequently, numerical simulations were carried out and electromechanical coupling process was obtained for different parameters. Simulation results verify correctness of the proposed model and results. Finally, experiments were carried out, self-synchronization and frequency hopping phenomenon were both observed, and results agree well with theoretical deduction and simulation results. These results provide theoretical foundations for multihammer synchronous vibration system and its synchronous control.

Multiwavelength search and studies of active galaxies and quasars

Science.gov (United States)

Mickaelian, Areg M.

2017-12-01

The Byurakan Astrophysical Observatory (BAO) has always been one of the centres for surveys and studies of active galaxies. Here we review our search and studies of active galaxies during last 30 years using various wavelength ranges, as well as some recent related works. These projects since late 1980s were focused on multiwavelength search and studies of AGN and Starbursts (SB). 1103 blue stellar objects (BSOs) on the basis of their UV-excess were selected using Markarian Survey (First Byurakan Survey, FBS) plates and Markarian's criteria used for the galaxies. Among many blue stars, QSOs and Seyfert galaxies were found by follow-up observations. 1577 IRAS point sources were optically identified using FBS low-dispersion spectra and many AGN, SB and high-luminosity IR galaxies (LIRG/ULIRG) were discovered. 32 extremely high IR/opt flux ratio galaxies were studies with Spitzer. 2791 ROSAT FSC sources were optically identified using Hamburg Quasar Survey (HQS) low-dispersion spectra and many AGN were discovered by follow-up observations. Fine analysis of emission line spectra was carried out using spectral line decomposition software to establish true profiles and calculate physical parameters for the emitting regions, as well as to study the spectral variability of these objects. X-ray and radio selection criteria were used to find new AGN and variable objects for further studies. We have estimated AGN content of X-ray sources as 52.9%. We have also combined IRAS PSC and FSC catalogs and compiled its extragalactic sample, which allowed us to estimate AGN content among IR sources as 23.7%. Multiwavelength approach allowed revealing many new AGN and SB and obtaining a number of interesting relations using their observational characteristics and physical properties.