Opting in and opting out: a grounded theory of nursing's contribution to inpatient rehabilitation.

Science.gov (United States)

Pryor, Julie; Walker, Annette; O'Connell, Beverly; Worrall-Carter, Linda

2009-12-01

To develop a grounded theory of nursing's contribution to patient rehabilitation from the perspective of nurses working in inpatient rehabilitation. Grounded theory method, informed by the theoretical perspective of symbolic interactionism, was used to guide data collection and analysis, and the development of a grounded theory. Five inpatient rehabilitation units in Australia. Thirty-five registered and 18 enrolled nurses participated in audio-taped interviews and/or were observed during periods of their everyday practice. The analysis revealed a situation whereby nurses made decisions about when to 'opt in' and when to 'opt out' of inpatient rehabilitation. This occurred on two levels: with their interaction with patients and allied health professionals, and when faced with negative system issues that impacted on their ability to contribute to patient rehabilitation. The primary contribution nurses made to inpatient rehabilitation was working directly with patients, enabling them to self-care. Nurses coached patients when their decisions about 'opting in' and 'opting out' were based on assessment of the person in their particular context. In contrast, the nurses mostly distanced themselves from system-based problems, 'opting out' of addressing them. They did this not to make their working lives easier, but more manageable. System-based problems impacted negatively on the nurses' ability to deliver comprehensive rehabilitation care. As a consequence, some nurses felt unable to influence the care and they withdrew professionally to make their work lives more manageable.

Optimizing Opt-Out Consent for Record Linkage

Directory of Open Access Journals (Sweden)

Das Marcel

2014-09-01

Full Text Available This article reports on a study testing the effects of different ways of administering an opt-out consent for record linkage in a probability-based Internet panel. First, we conducted cognitive interviews to explore reactions to a draft version of the opt-out consent text. Second, we conducted a two-factor experiment to test the effects of content manipulations and mode. The results indicate that the way in which respondents were informed did not have much effect on opting out. Results from a follow-up survey on attitudes regarding privacy, confidentiality, and trust, along with knowledge questions about the process of linking, showed no evidence that presenting the opt-out consent statement makes respondents more concerned about privacy. Knowledge about the aspects of record linkage is generally not high. When looking at long-term effects of sending an opt-out consent statement, we found no evidence that this leads to higher attrition or lower participation rates.

12 CFR 334.27 - Renewal of opt-out.

Science.gov (United States)

2010-01-01

... 12 Banks and Banking 4 2010-01-01 2010-01-01 false Renewal of opt-out. 334.27 Section 334.27 Banks and Banking FEDERAL DEPOSIT INSURANCE CORPORATION REGULATIONS AND STATEMENTS OF GENERAL POLICY FAIR CREDIT REPORTING Affiliate Marketing § 334.27 Renewal of opt-out. (a) Renewal notice and opt-out...

A randomised controlled trial to compare opt-in and opt-out parental consent for childhood vaccine safety surveillance using data linkage: study protocol

OpenAIRE

Berry, Jesia G; Ryan, Philip; Braunack-Mayer, Annette J; Duszynski, Katherine M; Xafis, Vicki; Gold, Michael S

2011-01-01

Abstract Background The Vaccine Assessment using Linked Data (VALiD) trial compared opt-in and opt-out parental consent for a population-based childhood vaccine safety surveillance program using data linkage. A subsequent telephone interview of all households enrolled in the trial elicited parental intent regarding the return or non-return of reply forms for opt-in and opt-out consent. This paper describes the rationale for the trial and provides an overview of the design and methods. Methods...

A randomised controlled trial to compare opt-in and opt-out parental consent for childhood vaccine safety surveillance using data linkage: study protocol

Directory of Open Access Journals (Sweden)

Duszynski Katherine M

2011-01-01

Full Text Available Abstract Background The Vaccine Assessment using Linked Data (VALiD trial compared opt-in and opt-out parental consent for a population-based childhood vaccine safety surveillance program using data linkage. A subsequent telephone interview of all households enrolled in the trial elicited parental intent regarding the return or non-return of reply forms for opt-in and opt-out consent. This paper describes the rationale for the trial and provides an overview of the design and methods. Methods/Design Single-centre, single-blind, randomised controlled trial (RCT stratified by firstborn status. Mothers who gave birth at one tertiary South Australian hospital were randomised at six weeks post-partum to receive an opt-in or opt-out reply form, along with information explaining data linkage. The primary outcome at 10 weeks post-partum was parental participation in each arm, as indicated by the respective return or non-return of a reply form (or via telephone or email response. A subsequent telephone interview at 10 weeks post-partum elicited parental intent regarding the return or non-return of the reply form, and attitudes and knowledge about data linkage, vaccine safety, consent preferences and vaccination practices. Enrolment began in July 2009 and 1,129 households were recruited in a three-month period. Analysis has not yet been undertaken. The participation rate and selection bias for each method of consent will be compared when the data are analysed. Discussion The VALiD RCT represents the first trial of opt-in versus opt-out consent for a data linkage study that assesses consent preferences and intent compared with actual opting in or opting out behaviour, and socioeconomic factors. The limitations to generalisability are discussed. Trial registration Australian New Zealand Clinical Trials Registry ACTRN12610000332022

A randomised controlled trial to compare opt-in and opt-out parental consent for childhood vaccine safety surveillance using data linkage: study protocol.

Science.gov (United States)

Berry, Jesia G; Ryan, Philip; Braunack-Mayer, Annette J; Duszynski, Katherine M; Xafis, Vicki; Gold, Michael S

2011-01-04

The Vaccine Assessment using Linked Data (VALiD) trial compared opt-in and opt-out parental consent for a population-based childhood vaccine safety surveillance program using data linkage. A subsequent telephone interview of all households enrolled in the trial elicited parental intent regarding the return or non-return of reply forms for opt-in and opt-out consent. This paper describes the rationale for the trial and provides an overview of the design and methods. Single-centre, single-blind, randomised controlled trial (RCT) stratified by firstborn status. Mothers who gave birth at one tertiary South Australian hospital were randomised at six weeks post-partum to receive an opt-in or opt-out reply form, along with information explaining data linkage. The primary outcome at 10 weeks post-partum was parental participation in each arm, as indicated by the respective return or non-return of a reply form (or via telephone or email response). A subsequent telephone interview at 10 weeks post-partum elicited parental intent regarding the return or non-return of the reply form, and attitudes and knowledge about data linkage, vaccine safety, consent preferences and vaccination practices. Enrolment began in July 2009 and 1,129 households were recruited in a three-month period. Analysis has not yet been undertaken. The participation rate and selection bias for each method of consent will be compared when the data are analysed. The VALiD RCT represents the first trial of opt-in versus opt-out consent for a data linkage study that assesses consent preferences and intent compared with actual opting in or opting out behaviour, and socioeconomic factors. The limitations to generalisability are discussed. Australian New Zealand Clinical Trials Registry ACTRN12610000332022.

40 CFR 96.85 - NOX Budget opt-in permit contents.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 20 2010-07-01 2010-07-01 false NOX Budget opt-in permit contents. 96... (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS Individual Unit Opt-ins § 96.85 NOX Budget opt-in permit contents. (a) Each NOX Budget opt-in permit...

40 CFR 97.85 - NOX Budget opt-in permit contents.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 20 2010-07-01 2010-07-01 false NOX Budget opt-in permit contents. 97... (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS Individual Unit Opt-ins. § 97.85 NOX Budget opt-in permit contents. (a) Each NOX Budget opt-in permit will contain all elements...

Nuclear energy: the cost of opting-out

International Nuclear Information System (INIS)

Mueller, U.

2003-01-01

This article discusses the results of a study made on the financial and ecological costs that would be incurred if Switzerland opted out of the use of nuclear energy. Figures are quoted for the costs if two Swiss popular initiatives on the subject of opting out of nuclear energy were accepted in voting. The disadvantages offered by the alternatives such as combined gas and steam-turbine power plant, photovoltaics and wind power are quoted. Possible negative effects of opting out on the Swiss economy are looked at and the political aspects of renewing operational permits for nuclear power stations are discussed

The OptD-multi method in LiDAR processing

International Nuclear Information System (INIS)

Błaszczak-Bąk, Wioleta; Sobieraj-Żłobińska, Anna; Kowalik, Michał

2017-01-01

New and constantly developing technology for acquiring spatial data, such as LiDAR (light detection and ranging), is a source for large volume of data. However, such amount of data is not always needed for developing the most popular LiDAR products: digital terrain model (DTM) or digital surface model. Therefore, in many cases, the number of contained points are reduced in the pre-processing stage. The degree of reduction is determined by the algorithm used, which should enable the user to obtain a dataset appropriate and optimal for the planned purpose. The aim of this article is to propose a new Optimum Dataset method (OptD method) in the processing of LiDAR point clouds. The OptD method can reduce the number of points in a dataset for the specified optimization criteria concerning the characteristics of generated DTM. The OptD method can be used in two variants: OptD-single (one criterion for optimization) and OptD-multi (two or more optimization criteria). The OptD-single method has been thoroughly tested and presented by Błaszczak-Bąk (2016 Acta Geodyn. Geomater . 13/4 379–86). In this paper the authors discussed the OptD-multi method. (paper)

17 CFR 248.124 - Reasonable opportunity to opt out.

Science.gov (United States)

2010-04-01

...” to indicate their opt out preference or that requires the consumer to check one of two blank check... affiliate to make marketing solicitations to a consumer about your products or services unless the consumer... a reasonable opportunity to opt out. The consumer is given a reasonable opportunity to opt out if...

40 CFR 97.83 - Applying for NOX Budget opt-in permit.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Applying for NOX Budget opt-in permit... PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS Individual Unit Opt-ins. § 97.83 Applying for NOX Budget opt-in permit. (a) Applying for initial NO X Budget opt...

Uptake of voluntary counselling and testing among young people participating in an HIV prevention trial: comparison of opt-out and opt-in strategies.

Directory of Open Access Journals (Sweden)

Kathy Baisley

Full Text Available HIV voluntary counselling and testing (VCT is an integral component of HIV prevention and treatment programmes. However, testing coverage in sub-Saharan Africa is still low, particularly among young people. As treatment becomes more widely available, strategies to expand VCT coverage are critically important. We compare VCT uptake using two delivery strategies (opt-in and opt-out within the MEMA kwa Vijana trial in 20 communities in northwest Tanzania.We analysed data from 12,590 young persons (median (IQR age 22 years (20-23 to assess the effect of delivery strategy on VCT uptake. Ten communities used an opt-in approach and 10 used opt-out, balanced across intervention and control. Conditional logistic regression was used to examine factors associated with uptake within each strategy.VCT uptake was significantly higher with the opt-out approach (90.9% vs 60.5%, prevalence ratio = 1.51, CI = 1.41-1.62. Among females, uptake in the opt-out approach was associated with decreased knowledge of HIV acquisition, sex with a casual partner, and being HSV-2 seronegative; among males, uptake was associated with lower education and increasing lifetime partners. In contrast, uptake using the opt-in approach varied by ethnic group, religion and marital status, and increased with increasing knowledge of STI acquisition (males or pregnancy prevention (females.VCT uptake among young people was extremely high when offered an opt-out strategy. Sociodemographic and knowledge factors affected uptake in different ways depending on delivery strategy. Increased knowledge may increase young persons' self-efficacy, which may have a different impact on testing uptake, depending on the approach used.

16 CFR 680.21 - Affiliate marketing opt-out and exceptions.

Science.gov (United States)

2010-01-01

... marketing purposes to a consumer with whom you have a pre-existing business relationship; (2) To facilitate... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Affiliate marketing opt-out and exceptions... AFFILIATE MARKETING § 680.21 Affiliate marketing opt-out and exceptions. (a) Initial notice and opt-out...

12 CFR 717.22 - Scope and duration of opt-out.

Science.gov (United States)

2010-01-01

... CREDIT REPORTING Affiliate Marketing § 717.22 Scope and duration of opt-out. (a) Scope of opt-out. (1) In... as described in the notice to make solicitations to the consumer. (2) Continuing relationship. (i) In general. If the consumer establishes a continuing relationship with you or your affiliate, an opt-out...

12 CFR 571.22 - Scope and duration of opt-out.

Science.gov (United States)

2010-01-01

... REPORTING Affiliate Marketing § 571.22 Scope and duration of opt-out. (a) Scope of opt-out—(1) In general... described in the notice to make solicitations to the consumer. (2) Continuing relationship—(i) In general. If the consumer establishes a continuing relationship with you or your affiliate, an opt-out notice...

16 CFR 680.22 - Scope and duration of opt-out.

Science.gov (United States)

2010-01-01

... MARKETING § 680.22 Scope and duration of opt-out. (a) Scope of opt-out—(1) In general. Except as otherwise... make solicitations to the consumer. (2) Continuing relationship—(i) In general. If the consumer establishes a continuing relationship with you or your affiliate, an opt-out notice may apply to eligibility...

The Diplomacy of Opting Out

DEFF Research Database (Denmark)

Adler-Nissen, Rebecca

and Home Affairs. Theoretically, the study offers a political sociology of European integration, which is seen as driven by politico-administrative struggling for capital in quasi-autonomous fields. This approach can be used more generally by EU and IR scholars to understand social dynamics of inclusion...... to upholding a doxa of ‘ever closer union among the peoples of Europe'. Empirically, the thesis provides the first extensive study of the diplomatic practices of the two champions of opting out - the UK and Denmark - when they handle their most important opt-outs from the Economic Monetary Union and Justice...... the everyday social setting of international and regional governance....

12 CFR 41.22 - Scope and duration of opt-out.

Science.gov (United States)

2010-01-01

... Affiliate Marketing § 41.22 Scope and duration of opt-out. (a) Scope of opt-out. (1) In general. Except as... the notice to make solicitations to the consumer. (2) Continuing relationship. (i) In general. If the consumer establishes a continuing relationship with a bank or its affiliate, an opt-out notice may apply to...

Difficult OptEase Filter Retrievals After Prolonged Indwelling Times

Energy Technology Data Exchange (ETDEWEB)

Van Ha, Thuong G., E-mail: tgvanha@radiology.bsd.uchicago.edu; Kang, Lisa; Lorenz, Jonathan; Zangan, Steven; Navuluri, Rakesh; Straus, Christopher; Funaki, Brian [University of Chicago, Section of Interventional Radiology, Department of Radiology (United States)

2013-08-01

PurposeThe OptEase vena cave filter (Cordis, Piscataway, NJ) is commercially available as a retrievable or permanent filter with short recommended indwelling time, presumably due to extensive contact of the filter side struts with the inferior vena cava wall and subsequent neointimal hyperplasia leading to incorporation. Our purpose was to evaluate OptEase filter retrievals with a long indwelling time period that required unconventional retrieval techniques.Materials and MethodsWe retrospectively reviewed patients who underwent OptEase filter retrieval with long undwelling times requiring additional maneuvers for retrieval. Techniques used included rigid endobronchial forceps dissection and wire-through-loop snare. Each patient underwent postretrieval venogram to evaluate for possible complications. In addition, patients had clinical follow-up 2 weeks after the retrieval procedure.ResultsThere were three patients (2 women, 1 man; average age 64 years) who underwent OptEase filter retrieval. The mean indwelling time was 6.4 months. The indwelling filters were successfully retrieved. There were no complications. Postprocedural follow-up showed no clinical pathology.ConclusionUnconventional techniques aided in the retrieval of OptEase filters with long indwelling times.

Difficult OptEase Filter Retrievals After Prolonged Indwelling Times

International Nuclear Information System (INIS)

Van Ha, Thuong G.; Kang, Lisa; Lorenz, Jonathan; Zangan, Steven; Navuluri, Rakesh; Straus, Christopher; Funaki, Brian

2013-01-01

PurposeThe OptEase vena cave filter (Cordis, Piscataway, NJ) is commercially available as a retrievable or permanent filter with short recommended indwelling time, presumably due to extensive contact of the filter side struts with the inferior vena cava wall and subsequent neointimal hyperplasia leading to incorporation. Our purpose was to evaluate OptEase filter retrievals with a long indwelling time period that required unconventional retrieval techniques.Materials and MethodsWe retrospectively reviewed patients who underwent OptEase filter retrieval with long undwelling times requiring additional maneuvers for retrieval. Techniques used included rigid endobronchial forceps dissection and wire-through-loop snare. Each patient underwent postretrieval venogram to evaluate for possible complications. In addition, patients had clinical follow-up 2 weeks after the retrieval procedure.ResultsThere were three patients (2 women, 1 man; average age 64 years) who underwent OptEase filter retrieval. The mean indwelling time was 6.4 months. The indwelling filters were successfully retrieved. There were no complications. Postprocedural follow-up showed no clinical pathology.ConclusionUnconventional techniques aided in the retrieval of OptEase filters with long indwelling times

12 CFR 222.27 - Renewal of opt-out.

Science.gov (United States)

2010-01-01

... 12 Banks and Banking 3 2010-01-01 2010-01-01 false Renewal of opt-out. 222.27 Section 222.27 Banks and Banking FEDERAL RESERVE SYSTEM (CONTINUED) BOARD OF GOVERNORS OF THE FEDERAL RESERVE SYSTEM FAIR CREDIT REPORTING (REGULATION V) Affiliate Marketing § 222.27 Renewal of opt-out. (a) Renewal notice and...

12 CFR 717.27 - Renewal of opt-out.

Science.gov (United States)

2010-01-01

... applies. (2) Renewal period. Each opt-out renewal must be effective for a period of at least five years as... companies, or their successors, that jointly provided the previous opt-out notice. (b) Contents of renewal... provided by multiple companies with the ABC name or multiple companies in the ABC group or family of...

Private International Law Issues in Opt-out and Opt-in Instruments of Harmonization

DEFF Research Database (Denmark)

Fogt, Morten Midtgaard

2013-01-01

of Goods from 1980 (CISG) and the European Commission Proposal for a common European Sales Law from 2011 (CESL). Although the two instruments of substantial harmonization regulate the same area of civil law, they differ with respect to the type of formal instrument of harmonization, the material, personal......This article deals with opt-in and opt-out instruments of harmonization, how they apply and compete. It analyses the Private International Law (PIL) issues which arise and bases the analysis on the two instruments of harmonization – the Vienna Convention on Contract for the International Sale...... into these questions and argues, inter alia, that the CISG as a global international convention should have priority over the regional CESL, that the choice of the CESL should be based on a PIL choice of binding European ‘Community rules of law’, that both instruments cannot possible overrule the established PIL...

Iron deficiency regulated OsOPT7 is essential for iron homeostasis in rice.

Science.gov (United States)

Bashir, Khurram; Ishimaru, Yasuhiro; Itai, Reiko Nakanishi; Senoura, Takeshi; Takahashi, Michiko; An, Gynheung; Oikawa, Takaya; Ueda, Minoru; Sato, Aiko; Uozumi, Nobuyuki; Nakanishi, Hiromi; Nishizawa, Naoko K

2015-05-01

The molecular mechanism of iron (Fe) uptake and transport in plants are well-characterized; however, many components of Fe homeostasis remain unclear. We cloned iron-deficiency-regulated oligopeptide transporter 7 (OsOPT7) from rice. OsOPT7 localized to the plasma membrane and did not transport Fe(III)-DMA or Fe(II)-NA and GSH in Xenopus laevis oocytes. Furthermore OsOPT7 did not complement the growth of yeast fet3fet4 mutant. OsOPT7 was specifically upregulated in response to Fe-deficiency. Promoter GUS analysis revealed that OsOPT7 expresses in root tips, root vascular tissue and shoots as well as during seed development. Microarray analysis of OsOPT7 knockout 1 (opt7-1) revealed the upregulation of Fe-deficiency-responsive genes in plants grown under Fe-sufficient conditions, despite the high Fe and ferritin concentrations in shoot tissue indicating that Fe may not be available for physiological functions. Plants overexpressing OsOPT7 do not exhibit any phenotype and do not accumulate more Fe compared to wild type plants. These results indicate that OsOPT7 may be involved in Fe transport in rice.

40 CFR 96.83 - Applying for NOX Budget opt-in permit.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Applying for NOX Budget opt-in permit... PROGRAMS (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS Individual Unit Opt-ins § 96.83 Applying for NOX Budget opt-in permit. (a) Applying for...

12 CFR 334.23 - Contents of opt-out notice; consolidated and equivalent notices.

Science.gov (United States)

2010-01-01

... of the joint consumers may exercise the right to opt out. (ii) The opt-out notice must explain how an...) Alternative contents. If the consumer is afforded a broader right to opt out of receiving marketing than is... a clear, conspicuous, and concise notice that accurately discloses the consumer's opt-out rights. (4...

12 CFR 222.23 - Contents of opt-out notice; consolidated and equivalent notices.

Science.gov (United States)

2010-01-01

... consumers. Any of the joint consumers may exercise the right to opt out. (ii) The opt-out notice must...) Alternative contents. If the consumer is afforded a broader right to opt out of receiving marketing than is... a clear, conspicuous, and concise notice that accurately discloses the consumer's opt-out rights. (4...

12 CFR 571.25 - Reasonable and simple methods of opting out.

Science.gov (United States)

2010-01-01

... CREDIT REPORTING Affiliate Marketing § 571.25 Reasonable and simple methods of opting out. (a) In general... out, such as a form that can be electronically mailed or processed at an Internet Web site, if the... (15 U.S.C. 6801 et seq.), the affiliate sharing opt-out under the Act, and the affiliate marketing opt...

16 CFR 680.25 - Reasonable and simple methods of opting out.

Science.gov (United States)

2010-01-01

... AFFILIATE MARKETING § 680.25 Reasonable and simple methods of opting out. (a) In general. You must not use... a form that can be electronically mailed or processed at an Internet Web site, if the consumer..., 15 U.S.C. 6801 et seq., the affiliate sharing opt-out under the Act, and the affiliate marketing opt...

Sacrificio cortoplacista adaptativo 2opt (SCA_2opt: Una heurística inspirada en el pensamiento sistémico

Directory of Open Access Journals (Sweden)

Jorge Pérez Rave

2014-03-01

Full Text Available Se detalla el origen de dos noveles heurísticas para el TSP simétrico, inspiradas en el pensamiento sistémico: Sacrificio Cortoplacista Adaptativo 2-opt (SCA_2opt y SCA_2_opt_r. Estas surgen del análisis sistémico de la regla de decisión Vecino más cercano, identificándosele el arquetipo "Soluciones contraproducentes". El SCA se basa en que el agente viajero renuncie en un momento dado a una ciudad inmediatamente cercana, y se traslade hacia la segunda ciudad más cercana disponible. A partir de ello, se continúa con la regla del vecino más cercano. Cada que se realiza el SCA (búsqueda global se efectúa una búsqueda local 2_opt. Considerando el binomio eficacia y eficiencia, las dos heurísticas se muestran prometedoras en comparación multicriterio contra 19 metaheurísticas. Se evidencia que el pensamiento sistémico es un campo de inspiración viable para el desarrollo de métodos de optimización combinatoria; se plasman preguntas emergentes para desarrollos futuros, que permitan continuar integrando elementos de la optimización clásica con el pensamiento sistémico; áreas tradicionalmente vistas como antagónicas, pero cuyo diálogo se muestra favorable en este artículo.

Improving the ensemble optimization method through covariance matrix adaptation (CMA-EnOpt)

NARCIS (Netherlands)

Fonseca, R.M.; Leeuwenburgh, O.; Hof, P.M.J. van den; Jansen, J.D.

2013-01-01

Ensemble Optimization (EnOpt) is a rapidly emerging method for reservoir model based production optimization. EnOpt uses an ensemble of controls to approximate the gradient of the objective function with respect to the controls. Current implementations of EnOpt use a Gaussian ensemble with a

12 CFR 571.26 - Delivery of opt-out notices.

Science.gov (United States)

2010-01-01

... Affiliate Marketing § 571.26 Delivery of opt-out notices. (a) In general. The opt-out notice must be... the notice on the Internet Web site at which the consumer obtained a product or service electronically... on an Internet Web site without requiring the consumer to acknowledge receipt of the notice. ...

12 CFR 41.26 - Delivery of opt-out notices.

Science.gov (United States)

2010-01-01

... Affiliate Marketing § 41.26 Delivery of opt-out notices. (a) In general. The opt-out notice must be provided... the notice on the Internet Web site at which the consumer obtained a product or service electronically... on an Internet Web site without requiring the consumer to acknowledge receipt of the notice. ...

Opt-out donation and tacit consent: a reply to Wilkinson and De Wispelaere.

Science.gov (United States)

Saunders, Ben

2012-02-01

In this reply to Wilkinson and De Wispelaere, I argue that an opt-out donation system can be regarded as tacit consent. I first separate the opt-in/opt-out issue from that of the role that the family ought to play. I then argue that what De Wispelaere calls minimal approval-tracking is not obviously necessary and that, even if it were, opt-out schemes can satisfy this requirement.

17 CFR 160.7 - Form of opt out notice to consumers; opt out methods.

Science.gov (United States)

2010-04-01

... consumer agrees, electronically. (2) When a customer relationship terminates, the customer's opt out... that relationship. If the individual subsequently establishes a new customer relationship with you, the... relationships. (1) If two or more consumers jointly obtain a financial product or service from you, you may...

12 CFR 717.26 - Delivery of opt-out notices.

Science.gov (United States)

2010-01-01

... CREDIT REPORTING Affiliate Marketing § 717.26 Delivery of opt-out notices. (a) In general. The opt-out... the notice; or (4) Posts the notice on the Internet Web site at which the consumer obtained a product... notice; or (3) Posts the notice on an Internet Web site without requiring the consumer to acknowledge...

12 CFR 222.24 - Reasonable opportunity to opt out.

Science.gov (United States)

2010-01-01

... consumers to write a “yes” or “no” to indicate their opt-out preference or that requires the consumer to... opt out. (a) In general. You must not use eligibility information about a consumer that you receive from an affiliate to make a solicitation to the consumer about your products or services, unless the...

12 CFR 571.24 - Reasonable opportunity to opt out.

Science.gov (United States)

2010-01-01

... completing a form that requires consumers to write a “yes” or “no” to indicate their opt-out preference or... eligibility information about a consumer that you receive from an affiliate to make a solicitation to the consumer about your products or services, unless the consumer is provided a reasonable opportunity to opt...

Assessment Opt-Out Policies: State Responses to Parent Pushback. ECS Education Trends

Science.gov (United States)

Aragon, Stephanie; Rowland, Julie; Wixom, Micah Ann

2015-01-01

With new state assessments kicking into full swing across the country, schools are seeing more and more parents wanting to opt out their children. Determining whether states allow assessment opt-outs can be complex and is constantly evolving. In some states the answer is clear: State policies either allow or prohibit state assessment opt-outs, or…

12 CFR 717.21 - Affiliate marketing opt-out and exceptions.

Science.gov (United States)

2010-01-01

... 12 Banks and Banking 6 2010-01-01 2010-01-01 false Affiliate marketing opt-out and exceptions. 717.21 Section 717.21 Banks and Banking NATIONAL CREDIT UNION ADMINISTRATION REGULATIONS AFFECTING CREDIT UNIONS FAIR CREDIT REPORTING Affiliate Marketing § 717.21 Affiliate marketing opt-out and exceptions. (a...

12 CFR 334.22 - Scope and duration of opt-out.

Science.gov (United States)

2010-01-01

... POLICY FAIR CREDIT REPORTING Affiliate Marketing § 334.22 Scope and duration of opt-out. (a) Scope of opt... relationship—(i) In general. If the consumer establishes a continuing relationship with you or your affiliate... continuing relationship or multiple continuing relationships that the consumer establishes with you or your...

12 CFR 571.21 - Affiliate marketing opt-out and exceptions.

Science.gov (United States)

2010-01-01

... solicitation for marketing purposes to a consumer with whom you have a pre-existing business relationship; (2... 12 Banks and Banking 5 2010-01-01 2010-01-01 false Affiliate marketing opt-out and exceptions. 571... CREDIT REPORTING Affiliate Marketing § 571.21 Affiliate marketing opt-out and exceptions. (a) Initial...

Opt-out screening strategy for HIV infection among patients attending emergency departments: systematic review and meta-analysis.

Science.gov (United States)

Henriquez-Camacho, C; Villafuerte-Gutierrez, P; Pérez-Molina, J A; Losa, J; Gotuzzo, E; Cheyne, N

2017-07-01

International health agencies have promoted nontargeted universal (opt-out) HIV screening tests in different settings, including emergency departments (EDs). We performed a systematic review and meta-analysis to assess the testing uptake of strategies (opt-in targeted, opt-in nontargeted and opt-out) to detect new cases of HIV infection in EDs. We searched the Pubmed and Embase databases, from 1984 to April 2015, for opt-in and opt-out HIV diagnostic strategies used in EDs. Randomized controlled or quasi experimental studies were included. We assessed the percentage of positive individuals tested for HIV infection in each programme (opt-in and opt-out strategies). The mean percentage was estimated by combining studies in a random-effect meta-analysis. The percentages of individuals tested in the programmes were compared in a random-effect meta-regression model. Data were analysed using stata version 12. Quality assessments were performed using the Newcastle-Ottawa Scale. Of the 90 papers identified, 28 were eligible for inclusion. Eight trials used opt-out, 18 trials used opt-in, and two trials used both to detect new cases of HIV infection. The test was accepted and taken by 75 155 of 172 237 patients (44%) in the opt-out strategy, and 73 581 of 382 992 patients (19%) in the opt-in strategy. The prevalence of HIV infection detected by the opt-out strategy was 0.40% (373 cases), that detected by the opt-in nontargeted strategy was 0.52% (419 cases), and that detected by the opt-in targeted strategy was 1.06% (52 cases). In this meta-analysis, the testing uptake of the opt-out strategy was not different from that of the opt-in strategy to detect new cases of HIV infection in EDs. © 2016 British HIV Association.

12 CFR 334.21 - Affiliate marketing opt-out and exceptions.

Science.gov (United States)

2010-01-01

... solicitation for marketing purposes to a consumer with whom you have a pre-existing business relationship; (2... 12 Banks and Banking 4 2010-01-01 2010-01-01 false Affiliate marketing opt-out and exceptions. 334... OF GENERAL POLICY FAIR CREDIT REPORTING Affiliate Marketing § 334.21 Affiliate marketing opt-out and...

Surface Roughness Measurements Utilizing Long-Range Surface-Plasma Waves

Science.gov (United States)

1984-11-01

8217 The theory dealt only with the depen- modes, one symmetric and one antisymmetric, dence of the real wave vector on the real part of that propagate...quantity, while the wave vector is complex. It is shown that for both the supported and unsup- From Eqs. (1) and (2) one obtains the real implic- ported...Opt. Soc. sabbatical leave from the University of Toledo. Am.). Optical feild enhancemeft by long-range surface- I" ouT In O’ in OUT way@, plasma waves

Assessing the impact of opt-out definitions in choice experiments

DEFF Research Database (Denmark)

Olsen, Søren Bøye; Campbell, Danny; Mørkbak, Morten Raun

that this heuristic has a larger impact when the opt-out is defined as respondents own typical (perceived) purchase than when defined as a none-of-these or a provided hypothetical alternative. We consequently stress the importance for researchers to be aware of these possible implications related to the definition...... of opt-out alternatives in choice experiments....

Compatibility with European law of opt-out legislation

International Nuclear Information System (INIS)

Feldmann, U.

2000-01-01

Should consensus with the utilities not be reached, Federal Minister for the Environment, Mr. Trittin, repeatedly announced to introduce opt-out legislation 'by dissent'. Both the constitutionality of such legislation and its compatibility with European law are topics of controversial debate in the literature. The decision taken by the Bavarian cabinet on February 8 in this year, to use all political and legal means against shutting down German nuclear power plants and, for this purpose, even to approach the European Commission on grounds of potential violation of European law, are reason enough to deal in more detail with the compatibility of an opt-out law with the Euratom Treaty and the EC Treaty. As the opt-out law does not yet exist, these considerations can only be of a theoretical nature. However, this is the working hypothesis assumed: Reprocessing is banned as of the entry into force of the opt-out law. This ban includes moving nuclear waste abroad for reprocessing. The peaceful use of nuclear power for electricity generation in power reactors operated for thirty years is forbidden. Older reactors may be run only for a transition period of another three years. (This includes abandoning the promotion purpose in the German Atomic Energy Act and a ban on building new power reactors). However, the operating life may be distributed in a flexible way. This contribution indicates that there are sound reasons and interesting approaches, respectively, in the literature for assuming that opting out by means of legislation, coupled with a ban on reprocessing, at least constitutes a violation of the freedom for goods and/or services. However, this cannot be derived unequivocally from either the Euratom Treaty or the EC Treaty or from rulings by the European Court of Justice. Ultimately, compatibility with European law of the ban on reprocessing can be decided only by the European Court of Justice. (orig.) [de

Opt-out as an acceptable method of obtaining consent in medical research: a short report.

LENUS (Irish Health Repository)

Vellinga, Akke

2011-04-06

Abstract Background A prospective cohort study was set up to investigate a possible association between antibiotic prescribing and antibiotic resistance of E. coli urinary tract infection in the community. Participation of patients with urinary tract infection was obtained through an opt-out methodology. This short paper reports on the acceptability of the opt-out recruitment approach. Methods Participating practices (22) were requested to send a urine sample from all patients presenting with symptoms of urinary tract infection. Upon receipt of the sample in the laboratory, a letter explaining the study, an opt-out form and a freepost envelope were sent to all adult patients. A website with additional information and including an \\'opt-out\\' button was set up for the study. Results A total of 1362 urine samples were submitted by the 22 participating practices representing 1178 adult patients of whom 193 actively responded to the letter: 142 opted out by letter, 15 through the website, 2 by phone and 12 sent the letter back without indication, making a total of 171 patients or 14.5% opt-out; the remaining 22 patients (1.9%) explicitly opted in. The total group consisted of 80% women and the mean age was 50.9 years (sd 20.8). No significant differences were found between patients who participated and those who opted out in terms of age, gender or whether the urine sample was positive or not. Conclusions Overall the opt-out method was well received and participation in the study reached 85.5%. The low number of complaints (2) indicates that this is a generally acceptable method of patient recruitment. The 14.5% opt-out shows that it effectively empowers patients to decline participation. The similarity between patients opting out and the rest of the patients is reassuring for extrapolation of the results of the study.

General k-opt submoves for the Lin-Kernighan TSP heuristic

DEFF Research Database (Denmark)

Helsgaun, Keld

2009-01-01

Local search with k-exchange neighborhoods, k-opt, is the most widely used heuristic method for the traveling salesman problem (TSP). This paper presents an effective implementation of k-opt in LKH-2, a variant of the Lin–Kernighan TSP heuristic. The effectiveness of the implementation...

The rise and fall of an opt-out system.

Science.gov (United States)

Nordfalk, Francisca; Hoeyer, Klaus

2018-04-01

In Denmark, citizens participate in register-based research without the possibility of opting out. However, in 1995 it was made possible for Danish citizens to register an opt-out called 'researcher protection' [ forskerbeskyttelse], which implied that researchers could not contact people to invite them to participate in research projects, such as clinical trials or questionnaries, based on their registrations in national registers. Data already registered could still be used for research. In 2014, this possibility of opt-out was revoked by law. The aims of this paper are to understand how the Danish researcher protection system came about, why it was terminated and what we can we learn from this example. We conducted a descriptive analysis of a copy of the former researcher protection register along with policies and media debate surrounding the rise and revocation of the researcher protection system. Our results show how both the inception and the abolishment of researcher protection appear to be ad hoc and without specified criteria of success. An examination of the recorded entries in the researcher protection registry could have led to changes in its administration as an alternative to its total abolition. In future opt-out systems, there should be focus on monitoring register practices and the purpose and criteria for evaluation must be defined prior to implementation.

12 CFR 334.25 - Reasonable and simple methods of opting out.

Science.gov (United States)

2010-01-01

... STATEMENTS OF GENERAL POLICY FAIR CREDIT REPORTING Affiliate Marketing § 334.25 Reasonable and simple methods... or processed at an Internet Web site, if the consumer agrees to the electronic delivery of... opt-out under the Act, and the affiliate marketing opt-out under the Act, by a single method, such as...

12 CFR 222.25 - Reasonable and simple methods of opting out.

Science.gov (United States)

2010-01-01

... FEDERAL RESERVE SYSTEM FAIR CREDIT REPORTING (REGULATION V) Affiliate Marketing § 222.25 Reasonable and... electronically mailed or processed at an Internet Web site, if the consumer agrees to the electronic delivery of... opt-out under the Act, and the affiliate marketing opt-out under the Act, by a single method, such as...

CiOpt: a program for optimization of the frequency response of linear circuits

OpenAIRE

Miró Sans, Joan Maria; Palà Schönwälder, Pere

1991-01-01

An interactive personal-computer program for optimizing the frequency response of linear lumped circuits (CiOpt) is presented. CiOpt has proved to be an efficient tool in improving designs where the inclusion of more accurate device models distorts the desired frequency response, as well as in device modeling. The outputs of CiOpt are the element values which best match the obtained and the desired frequency response. The optimization algorithms used (the Fletcher-Powell and Newton's methods,...

Opt-out of voluntary HIV testing: a Singapore hospital's experience.

Science.gov (United States)

Chua, Arlene C; Leo, Yee Sin; Cavailler, Philippe; Chu, Christine; Ng, Aloysius; Ng, Oon Tek; Krishnan, Prabha

2012-01-01

Since 2008, the Singapore Ministry of Health (MOH) has expanded HIV testing by increasing anonymous HIV test sites, as well as issuing a directive to hospitals to offer routine voluntary opt out inpatient HIV testing. We reviewed this program implemented at the end of 2008 at Tan Tock Seng Hospital (TTSH), the second largest acute care general hospital in Singapore. From January 2009 to December 2010, all inpatients aged greater or equal than 21 years were screened for HIV unless they declined or were not eligible for screening. We reviewed the implementation of the Opt Out testing policy. There were a total of 93,211 admissions; 41,543 patients were included based on HIV screening program eligibility criteria. Among those included, 79% (n = 32,675) opted out of HIV screening. The overall acceptance rate was 21%. Majority of eligible patients who were tested (63%) were men. The mean age of tested patients was 52 years. The opt out rate was significantly higher among females (OR: 1.5, 95%CI: 1.4-1.6), aged >60 years (OR: 2.3, 95%CI: 2.2-2.4) and Chinese ethnicity (OR: 1.7, 95%CI:1.6-1.8). The false positive rate of the HIV screening test is 0.56%. The proportion of patients with HIV infection among those who underwent HIV screening is 0.18%. All 16 confirmed HIV patients were linked to care. The default opt-in rate of inpatient HIV testing was low at Tan Tock Seng Hospital, Singapore. Efforts to address individual HIV risk perception and campaigns against HIV stigma are needed to encourage more individuals to be tested for HIV.

Augmenting short cheap talk scripts with a repeated opt-out reminder in choice experiment surveys

DEFF Research Database (Denmark)

Ladenburg, Jacob; Olsen, Søren Bøye

to choose the opt-out alternative if they find the experimentally designed alternatives too expensive. In an empirical Choice Experiment survey we find the Opt-Out Reminder to significantly reduce total WTP and to some extent also marginal WTP beyond the capability of the Cheap Talk applied without the Opt...

Subsurface Profile Mapping using 3-D Compressive Wave Imaging

Directory of Open Access Journals (Sweden)

Hazreek Z A M

2017-01-01

Full Text Available Geotechnical site investigation related to subsurface profile mapping was commonly performed to provide valuable data for design and construction stage based on conventional drilling techniques. From past experience, drilling techniques particularly using borehole method suffer from limitations related to expensive, time consuming and limited data coverage. Hence, this study performs subsurface profile mapping using 3-D compressive wave imaging in order to minimize those conventional method constraints. Field measurement and data analysis of compressive wave (p-wave, vp was performed using seismic refraction survey (ABEM Terraloc MK 8, 7 kg of sledgehammer and 24 units of vertical geophone and OPTIM (SeisOpt@Picker & SeisOpt@2D software respectively. Then, 3-D compressive wave distribution of subsurface studied was obtained using analysis of SURFER software. Based on 3-D compressive wave image analyzed, it was found that subsurface profile studied consist of three main layers representing top soil (vp = 376 – 600 m/s, weathered material (vp = 900 – 2600 m/s and bedrock (vp > 3000 m/s. Thickness of each layer was varied from 0 – 2 m (first layer, 2 – 20 m (second layer and 20 m and over (third layer. Moreover, groundwater (vp = 1400 – 1600 m/s starts to be detected at 2.0 m depth from ground surface. This study has demonstrated that geotechnical site investigation data related to subsurface profiling was applicable to be obtained using 3-D compressive wave imaging. Furthermore, 3-D compressive wave imaging was performed based on non destructive principle in ground exploration thus consider economic, less time, large data coverage and sustainable to our environment.

Opt-out of voluntary HIV testing: a Singapore hospital's experience.

Directory of Open Access Journals (Sweden)

Arlene C Chua

Full Text Available INTRODUCTION: Since 2008, the Singapore Ministry of Health (MOH has expanded HIV testing by increasing anonymous HIV test sites, as well as issuing a directive to hospitals to offer routine voluntary opt out inpatient HIV testing. We reviewed this program implemented at the end of 2008 at Tan Tock Seng Hospital (TTSH, the second largest acute care general hospital in Singapore. METHODS AND FINDINGS: From January 2009 to December 2010, all inpatients aged greater or equal than 21 years were screened for HIV unless they declined or were not eligible for screening. We reviewed the implementation of the Opt Out testing policy. There were a total of 93,211 admissions; 41,543 patients were included based on HIV screening program eligibility criteria. Among those included, 79% (n = 32,675 opted out of HIV screening. The overall acceptance rate was 21%. Majority of eligible patients who were tested (63% were men. The mean age of tested patients was 52 years. The opt out rate was significantly higher among females (OR: 1.5, 95%CI: 1.4-1.6, aged >60 years (OR: 2.3, 95%CI: 2.2-2.4 and Chinese ethnicity (OR: 1.7, 95%CI:1.6-1.8. The false positive rate of the HIV screening test is 0.56%. The proportion of patients with HIV infection among those who underwent HIV screening is 0.18%. All 16 confirmed HIV patients were linked to care. CONCLUSION: The default opt-in rate of inpatient HIV testing was low at Tan Tock Seng Hospital, Singapore. Efforts to address individual HIV risk perception and campaigns against HIV stigma are needed to encourage more individuals to be tested for HIV.

12 CFR 573.15 - Other exceptions to notice and opt out requirements.

Science.gov (United States)

2010-01-01

... consumer. (2) A consumer may revoke consent by subsequently exercising the right to opt out of future... PRIVACY OF CONSUMER FINANCIAL INFORMATION Exceptions § 573.15 Other exceptions to notice and opt out... consumer, provided that the consumer has not revoked the consent or direction; (2)(i) To protect the...

Millimeter‐wave INP DHBT power amplifier based on power‐optimized cascode configuration

DEFF Research Database (Denmark)

Johansen, Tom K.; Yan, Lei; Dupuy, Jean‐Yves

2013-01-01

This letter describes the use of a power‐optimized cascode configuration for obtaining maximum output power at millimeter‐wave (mm‐wave) frequencies for a two‐way combined power amplifier (PA). The PA has been fabricated in a high‐speed InP double heterojunction bipolar transistor technology and ...... configuration at mm‐wave frequencies are confirmed by both simulations and experimental results. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1178–1182, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27477...

Health-care providers' experiences with opt-out HIV testing: a systematic review.

Science.gov (United States)

Leidel, Stacy; Wilson, Sally; McConigley, Ruth; Boldy, Duncan; Girdler, Sonya

2015-01-01

HIV is now a manageable chronic disease with a good prognosis, but early detection and referral for treatment are vital. In opt-out HIV testing, patients are informed that they will be tested unless they decline. This qualitative systematic review explored the experiences, attitudes, barriers, and facilitators of opt-out HIV testing from a health-care provider (HCP) perspective. Four articles were included in the synthesis and reported on findings from approximately 70 participants, representing diverse geographical regions and a range of human development status and HIV prevalence. Two synthesized findings emerged: HCP attitudes and systems. The first synthesized finding encompassed HCP decision-making attitudes about who and when to test for HIV. It also included the assumptions the HCPs made about patient consequences. The second synthesized finding related to systems. System-related barriers to opt-out HIV testing included lack of time, resources, and adequate training. System-related facilitators included integration into standard practice, support of the medical setting, and electronic reminders. A common attitude among HCPs was the outdated notion that HIV is a terrible disease that equates to certain death. Some HCPs stated that offering the HIV test implied that the patient had engaged in immoral behaviour, which could lead to stigma or disengagement with health services. This paternalism diminished patient autonomy, because patients who were excluded from opt-out HIV testing could have benefited from it. One study highlighted the positive aspects of opt-out HIV testing, in which participants underscored the professional satisfaction that arose from making an HIV diagnosis, particularly when marginalized patients could be connected to treatment and social services. Recommendations for opt-out HIV testing should be disseminated to HCPs in a broad range of settings. Implementation of system-related factors such as electronic reminders and care coordination

Legal issues associated with opting out of the use of nuclear power

International Nuclear Information System (INIS)

Butzke, K.; Storr, S.

2000-01-01

The article is a summary of a conference held at Jena University at which the political issues of opting out of using nuclear power were scrutinized under aspects of (constitutional) law. The results of the conference were summed up in the Jena Theses about Opting out of the use of Nuclear Power. (orig.) [de

'We didn't have to dance around it': opt-out HIV testing among homeless and marginalised patients.

Science.gov (United States)

Leidel, Stacy; Leslie, Gavin; Boldy, Duncan; Davies, Andrew; Girdler, Sonya

2017-07-01

This study explored opt-out HIV testing in an Australian general practice. The aims were to: (1) determine the effect of the opt-out approach on the number of HIV tests performed; and (2) explore the acceptability of opt-out HIV testing from the healthcare providers' perspective. A prospective mixed-methods study of opt-out HIV testing over a 2-year period (March 2014-March 2016) was conducted. Implementation was based on a theoretical framework that was developed specifically for this study. The setting was Homeless Healthcare, a health service in Perth, Western Australia. The number of HIV tests conducted during the control year (usual practice) was compared with the intervention year (opt-out testing). After the intervention, the healthcare providers (n=8) were interviewed about their experiences with opt-out HIV testing. Directed content analysis was used to explore the qualitative data. HIV testing rates were low during both the control year and the intervention year (315 HIV tests (12% of the patient cohort) and 344 HIV tests (10%) respectively). Opt-out HIV testing was feasible and acceptable to the participating healthcare providers. Other health services could consider opt-out HIV testing for their patients to identify people with undiagnosed infections and sustain Australia's low HIV prevalence.

Standards, Assessments & Opting Out, Spring 2015

Science.gov (United States)

Advance Illinois, 2015

2015-01-01

In the spring, Illinois students will take new state assessments that reflect the rigor and relevance of the new Illinois Learning Standards. But some classmates will sit out and join the pushback against standardized testing. Opt-out advocates raise concerns about over-testing, and the resulting toll on students as well as the impact on classroom…

12 CFR 716.15 - Other exceptions to notice and opt out requirements.

Science.gov (United States)

2010-01-01

... insurance to the consumer. (2) A consumer may revoke consent by subsequently exercising the right to opt out... AFFECTING CREDIT UNIONS PRIVACY OF CONSUMER FINANCIAL INFORMATION Exceptions § 716.15 Other exceptions to... notice to consumers in § 716.4(a)(2), the opt out in §§ 716.7 and 716.10 and service providers and joint...

An Effective Implementation of K-opt Moves for the Lin-Kernighan TSP Heuristic

DEFF Research Database (Denmark)

Helsgaun, Keld

Local search with k-change neighborhoods, k-opt, is the most widely used heuristic method for the traveling salesman problem (TSP). This report presents an effective implementation of k-opt for the Lin- Kernighan TSP heuristic. The effectiveness of the implementation is demonstrated with extensive...

Rethinking HIV exceptionalism: the ethics of opt-out HIV testing in sub-Saharan Africa

Science.gov (United States)

2010-01-01

Abstract Opt-out testing for the human immunodeficiency virus (HIV) incorporates testing as a routine part of health care for all patients unless they refuse. The ethics of this approach to testing in sub-Saharan Africa is a source of controversy. Opt-out HIV testing is expected to improve survival by increasing case detection and thus linking more HIV-infected people to earlier treatment, provided there is effective patient follow-up and programme sustainability. At the population level, these benefits will likely outweigh the potential negative consequences of individuals experiencing HIV-related stigma. These justifications appeal to consequentialist moral theories that the acceptability of an action depends upon its outcomes. On the other hand, liberal moral theories state that the autonomy of individuals should always be protected unless restricting autonomy is necessary to protect the welfare of others. Opt-out consent may restrict autonomy and it is unclear whether it would benefit people other than those being tested. Yet, the doctrine of libertarian paternalism proposes that it is justifiable and desirable to use unobtrusive mechanisms to help individuals make choices to maximize their own welfare. Central to this idea are the premises featured by supporters of opt-out consent that individuals will not always make the best choices for their own welfare but they may be influenced to do so in ways that will not compromise their freedom of choice. Also important is the premise that all policies inevitably exert some such influence: opt-in consent encourages test refusal just as opt-out consent encourages acceptance. Based on these premises, opt-out testing may be an effective and ethically acceptable policy response to Africa’s HIV epidemic. PMID:20865076

Rethinking HIV exceptionalism: the ethics of opt-out HIV testing in sub-Saharan Africa.

Science.gov (United States)

April, Michael D

2010-09-01

Opt-out testing for the human immunodeficiency virus (HIV) incorporates testing as a routine part of health care for all patients unless they refuse. The ethics of this approach to testing in sub-Saharan Africa is a source of controversy. Opt-out HIV testing is expected to improve survival by increasing case detection and thus linking more HIV-infected people to earlier treatment, provided there is effective patient follow-up and programme sustainability. At the population level, these benefits will likely outweigh the potential negative consequences of individuals experiencing HIV-related stigma. These justifications appeal to consequentialist moral theories that the acceptability of an action depends upon its outcomes. On the other hand, liberal moral theories state that the autonomy of individuals should always be protected unless restricting autonomy is necessary to protect the welfare of others. Opt-out consent may restrict autonomy and it is unclear whether it would benefit people other than those being tested. Yet, the doctrine of libertarian paternalism proposes that it is justifiable and desirable to use unobtrusive mechanisms to help individuals make choices to maximize their own welfare. Central to this idea are the premises featured by supporters of opt-out consent that individuals will not always make the best choices for their own welfare but they may be influenced to do so in ways that will not compromise their freedom of choice. Also important is the premise that all policies inevitably exert some such influence: opt-in consent encourages test refusal just as opt-out consent encourages acceptance. Based on these premises, opt-out testing may be an effective and ethically acceptable policy response to Africa's HIV epidemic.

Deemed consent: Assessing the new opt-out approach to organ procurement in Wales

DEFF Research Database (Denmark)

Albertsen, Andreas

2018-01-01

In December 2015, Wales became the first country in the UK to move away from an opt-in system in organ procurement. The new legislation introduces the concept of deemed consent whereby a person who neither opt in nor opt out is deemed to have consented to donation. The data released by the National...... Health Service (NHS) in July 2017 provide an excellent opportunity to assess this legislation in light of concerns that it would decrease procurement rates for living and deceased donation, as well as sparking an increase in family refusals. None of these concerns have come to pass, with Wales...

Photonics-assisted wireless link based on mm-wave reconfigurable antennas

DEFF Research Database (Denmark)

Feliciano daCosta, Igor; Cerqueira Sodré, Arismar; Rodriguez Páez, Juan Sebastián

2017-01-01

The authors report a novel concept for photonics-assisted and broadband optical-wireless indoor networks based on optically-controlled reconfigurable antenna arrays (OCRAAs) and photonic down conversion (PDC) techniques, operating in the 28 and 38 GHz frequency bands. The antenna bandwidth is opt...... for access networks in the mm-wave frequency range....

OPT13B and OPTIM4 - computer codes for optical model calculations

International Nuclear Information System (INIS)

Pal, S.; Srivastava, D.K.; Mukhopadhyay, S.; Ganguly, N.K.

1975-01-01

OPT13B is a computer code in FORTRAN for optical model calculations with automatic search. A summary of different formulae used for computation is given. Numerical methods are discussed. The 'search' technique followed to obtain the set of optical model parameters which produce best fit to experimental data in a least-square sense is also discussed. Different subroutines of the program are briefly described. Input-output specifications are given in detail. A modified version of OPT13B specifications are given in detail. A modified version of OPT13B is OPTIM4. It can be used for optical model calculations where the form factors of different parts of the optical potential are known point by point. A brief description of the modifications is given. (author)

17 CFR 248.123 - Contents of opt out notice; consolidated and equivalent notices.

Science.gov (United States)

2010-04-01

... EXCHANGE COMMISSION (CONTINUED) REGULATIONS S-P AND S-AM Regulation S-AM: Limitations on Affiliate Marketing § 248.123 Contents of opt out notice; consolidated and equivalent notices. (a) Contents of opt out...) The name of the affiliate(s) providing the notice. If the notice is provided jointly by multiple...

OPT-TWO: Calculation code for two-dimensional MOX fuel models in the optimum concentration distribution

International Nuclear Information System (INIS)

Sato, Shohei; Okuno, Hiroshi; Sakai, Tomohiro

2007-08-01

OPT-TWO is a calculation code which calculates the optimum concentration distribution, i.e., the most conservative concentration distribution in the aspect of nuclear criticality safety, of MOX (mixed uranium and plutonium oxide) fuels in the two-dimensional system. To achieve the optimum concentration distribution, we apply the principle of flattened fuel importance distribution with which the fuel system has the highest reactivity. Based on this principle, OPT-TWO takes the following 3 calculation steps iteratively to achieve the optimum concentration distribution with flattened fuel importance: (1) the forward and adjoint neutron fluxes, and the neutron multiplication factor, with TWOTRAN code which is a two-dimensional neutron transport code based on the SN method, (2) the fuel importance, and (3) the quantity of the transferring fuel. In OPT-TWO, the components of MOX fuel are MOX powder, uranium dioxide powder and additive. This report describes the content of the calculation, the computational method, and the installation method of the OPT-TWO, and also describes the application method of the criticality calculation of OPT-TWO. (author)

The Opt-Out Continuation: Education, Work, and Motherhood from 1984 to 2012

Directory of Open Access Journals (Sweden)

Tanya Byker

2016-08-01

Full Text Available Debate about an increasing trend in highly educated women dropping out of the labor force to care for children—an opt-out revolution—has been considerable. I use unique features of the of Survey of Income and Program Participation—a large nationally representative sample, longitudinal structure, monthly labor-force outcomes, and repeated panels—to study trends in women's birth-related career interruptions over time and across the education spectrum. Methodologically, I use event studies to compare women's monthly labor-force outcomes on the extensive and intensive margins from twenty-four months before to twenty-four months after births in the 1980s, 1990s, and 2000s. Rather than an abrupt change in opting out, I find that the pattern of birth-related interruptions has changed surprisingly little over the past thirty years—substantial and sustained interruptions remain common for mothers in all education categories. Rather than a revolution, I find an opt-out continuation.

Using 2-Opt based evolution strategy for travelling salesman problem

Directory of Open Access Journals (Sweden)

Kenan Karagul

2016-03-01

Full Text Available Harmony search algorithm that matches the (µ+1 evolution strategy, is a heuristic method simulated by the process of music improvisation. In this paper, a harmony search algorithm is directly used for the travelling salesman problem. Instead of conventional selection operators such as roulette wheel, the transformation of real number values of harmony search algorithm to order index of vertex representation and improvement of solutions are obtained by using the 2-Opt local search algorithm. Then, the obtained algorithm is tested on two different parameter groups of TSPLIB. The proposed method is compared with classical 2-Opt which randomly started at each step and best known solutions of test instances from TSPLIB. It is seen that the proposed algorithm offers valuable solutions.

Second-Order Moller-Plesset Perturbation Theory for Molecular Dirac-Hartree-Fock Wave Functions

Science.gov (United States)

Dyall, Kenneth G.; Arnold, James O. (Technical Monitor)

1994-01-01

Moller-Plesset perturbation theory is developed to second order for a selection of Kramers restricted Dirac-Hartree-Fock closed and open-shell reference wave functions. The open-shell wave functions considered are limited to those with no more than two electrons in open shells, but include the case of a two-configuration SCF reference. Denominator shifts are included in the style of Davidson's OPT2 method. An implementation which uses unordered integrals with labels is presented, and results are given for a few test cases.

Why persons choose to opt out of an exception from informed consent cardiac arrest trial.

Science.gov (United States)

Nelson, Maria J; Deiorio, Nicole M; Schmidt, Terri A; Zive, Dana M; Griffiths, Denise; Newgard, Craig D

2013-06-01

We sought to characterize persons who requested to opt out of an exception from informed consent (EFIC) cardiac arrest trial and their reasons for opting out. At one site of a multi-site, out-of-hospital, cardiac arrest EFIC trial (September 2007 - June 2009), persons who did not want to participate in the study could request an opt-out "NO STUDY" bracelet to prevent trial enrollment. We surveyed all persons who requested a bracelet by phone interview, web or mail. Opt-out bracelets were advertised in all public communication about the study, including community consultation and public disclosure efforts. Survey questions included demographics, Likert scale items about attitudes toward the trial and research in general, plus open-ended questions. We used descriptive statistics for standardized questions and qualitative analysis to identify common themes from open-ended questions. Sixty bracelets were requested by 50 individuals. Surveys were completed by 46 persons (92% response rate). Seventy percent of respondents agreed emergency research is important, but 87% objected to any research without consent. In the qualitative analysis, 5 overlapping themes emerged: questioning the ethics of EFIC research; concerns about how the study would impact end-of-life preferences; subjective emotions including sarcasm, anger, and allusions to past unethical research; negative reference to unrelated public health controversies; and objections to the study protocol based on misinformation. A primary reason for opting out from this EFIC trial was opposition to all research without informed consent, despite stated support for emergency research. Understanding the demographics and beliefs of persons opting out may aid researchers planning EFIC studies and help provide clarity in future EFIC-related community education efforts. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

optBINS: Optimal Binning for histograms

Science.gov (United States)

Knuth, Kevin H.

2018-03-01

optBINS (optimal binning) determines the optimal number of bins in a uniform bin-width histogram by deriving the posterior probability for the number of bins in a piecewise-constant density model after assigning a multinomial likelihood and a non-informative prior. The maximum of the posterior probability occurs at a point where the prior probability and the the joint likelihood are balanced. The interplay between these opposing factors effectively implements Occam's razor by selecting the most simple model that best describes the data.

12 CFR 571.27 - Renewal of opt-out.

Science.gov (United States)

2010-01-01

... period. Each opt-out renewal must be effective for a period of at least five years as provided in § 571... (ii) As part of a joint renewal notice from two or more members of an affiliated group of companies... provided by multiple companies with the ABC name or multiple companies in the ABC group or family of...

OptFlux: an open-source software platform for in silico metabolic engineering.

Science.gov (United States)

Rocha, Isabel; Maia, Paulo; Evangelista, Pedro; Vilaça, Paulo; Soares, Simão; Pinto, José P; Nielsen, Jens; Patil, Kiran R; Ferreira, Eugénio C; Rocha, Miguel

2010-04-19

Over the last few years a number of methods have been proposed for the phenotype simulation of microorganisms under different environmental and genetic conditions. These have been used as the basis to support the discovery of successful genetic modifications of the microbial metabolism to address industrial goals. However, the use of these methods has been restricted to bioinformaticians or other expert researchers. The main aim of this work is, therefore, to provide a user-friendly computational tool for Metabolic Engineering applications. OptFlux is an open-source and modular software aimed at being the reference computational application in the field. It is the first tool to incorporate strain optimization tasks, i.e., the identification of Metabolic Engineering targets, using Evolutionary Algorithms/Simulated Annealing metaheuristics or the previously proposed OptKnock algorithm. It also allows the use of stoichiometric metabolic models for (i) phenotype simulation of both wild-type and mutant organisms, using the methods of Flux Balance Analysis, Minimization of Metabolic Adjustment or Regulatory on/off Minimization of Metabolic flux changes, (ii) Metabolic Flux Analysis, computing the admissible flux space given a set of measured fluxes, and (iii) pathway analysis through the calculation of Elementary Flux Modes. OptFlux also contemplates several methods for model simplification and other pre-processing operations aimed at reducing the search space for optimization algorithms. The software supports importing/exporting to several flat file formats and it is compatible with the SBML standard. OptFlux has a visualization module that allows the analysis of the model structure that is compatible with the layout information of Cell Designer, allowing the superimposition of simulation results with the model graph. The OptFlux software is freely available, together with documentation and other resources, thus bridging the gap from research in strain optimization

17 CFR 248.127 - Renewal of opt out elections.

Science.gov (United States)

2010-04-01

... (CONTINUED) REGULATIONS S-P AND S-AM Regulation S-AM: Limitations on Affiliate Marketing § 248.127 Renewal of... expires, you may not make marketing solicitations to a consumer who previously opted out, unless: (i) The....122(b). (3) Affiliates who may provide the notice. The notice required by this paragraph must be...

12 CFR 334.26 - Delivery of opt-out notices.

Science.gov (United States)

2010-01-01

... POLICY FAIR CREDIT REPORTING Affiliate Marketing § 334.26 Delivery of opt-out notices. (a) In general... the notice; or (4) Posts the notice on the Internet Web site at which the consumer obtained a product... notice; or (3) Posts the notice on an Internet Web site without requiring the consumer to acknowledge...

12 CFR 222.26 - Delivery of opt-out notices.

Science.gov (United States)

2010-01-01

... SYSTEM FAIR CREDIT REPORTING (REGULATION V) Affiliate Marketing § 222.26 Delivery of opt-out notices. (a... the affiliate providing the notice; or (4) Posts the notice on the Internet Web site at which the... affiliate providing the notice; or (3) Posts the notice on an Internet Web site without requiring the...

12 CFR 334.24 - Reasonable opportunity to opt out.

Science.gov (United States)

2010-01-01

...” to indicate their opt-out preference or that requires the consumer to check one of two blank check...) In general. You must not use eligibility information about a consumer that you receive from an affiliate to make a solicitation to the consumer about your products or services, unless the consumer is...

Deemed consent: assessing the new opt-out approach to organ procurement in Wales.

Science.gov (United States)

Albertsen, Andreas

2018-05-01

In December 2015, Wales became the first country in the UK to move away from an opt-in system in organ procurement. The new legislation introduces the concept of deemed consent whereby a person who neither opt in nor opt out is deemed to have consented to donation. The data released by the National Health Service (NHS) in July 2017 provide an excellent opportunity to assess this legislation in light of concerns that it would decrease procurement rates for living and deceased donation, as well as sparking an increase in family refusals. None of these concerns have come to pass, with Wales experiencing more registered donors, fewer family refusals and more living donations. However, as the number of actual donors has dropped slightly from a high level, the situation must be monitored closely in the years to come. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Advanced, High Power, Next Scale, Wave Energy Conversion Device

Energy Technology Data Exchange (ETDEWEB)

Mekhiche, Mike [Principal Investigator; Dufera, Hiz [Project Manager; Montagna, Deb [Business Point of Contact

2012-10-29

The project conducted under DOE contract DE‐EE0002649 is defined as the Advanced, High Power, Next Scale, Wave Energy Converter. The overall project is split into a seven‐stage, gated development program. The work conducted under the DOE contract is OPT Stage Gate III work and a portion of Stage Gate IV work of the seven stage product development process. The project effort includes Full Concept Design & Prototype Assembly Testing building on our existing PowerBuoy technology to deliver a device with much increased power delivery. Scaling‐up from 150kW to 500kW power generating capacity required changes in the PowerBuoy design that addressed cost reduction and mass manufacturing by implementing a Design for Manufacturing (DFM) approach. The design changes also focused on reducing PowerBuoy Installation, Operation and Maintenance (IO&M) costs which are essential to reducing the overall cost of energy. In this design, changes to the core PowerBuoy technology were implemented to increase capability and reduce both CAPEX and OPEX costs. OPT conceptually envisaged moving from a floating structure to a seabed structure. The design change from a floating structure to seabed structure would provide the implementation of stroke‐ unlimited Power Take‐Off (PTO) which has a potential to provide significant power delivery improvement and transform the wave energy industry if proven feasible.

Wind farm design in complex terrain: the FarmOpt methodology

DEFF Research Database (Denmark)

Feng, Ju; Shen, Wen Zhong; Hansen, Kurt Schaldemose

layout optimization algorithms. Various constraints are also modelled and considered in the design optimization problem for maximizing the annual energy production (AEP). A case study is presented to illustrate the effectiveness of the methodology. Further developments of the FarmOpt tool are also...

A parallel 2-opt algorithm for the traveling salesman problem

NARCIS (Netherlands)

Verhoeven, M.G.A.; Aarts, E.H.L.; Swinkels, P.C.J.

1995-01-01

We present a scalable parallel local search algorithm based on data parallelism. The concept of distributed neighborhood structures is introduced, and applied to the Traveling Salesman Problem (TSP). Our parallel local search algorithm finds the same quality solutions as the classical 2-opt

12 CFR 717.24 - Reasonable opportunity to opt out.

Science.gov (United States)

2010-01-01

... completing a form that requires consumers to write a “yes” or “no” to indicate their opt-out preference or.... You must not use eligibility information about a consumer that you receive from an affiliate to make a solicitation to the consumer about your products or services, unless the consumer is provided a reasonable...

12 CFR 41.24 - Reasonable opportunity to opt out.

Science.gov (United States)

2010-01-01

... completing a form that requires consumers to write a “yes” or “no” to indicate their opt-out preference or... eligibility information about a consumer that it receives from an affiliate to make a solicitation to the consumer about the bank's products or services, unless the consumer is provided a reasonable opportunity to...

12 CFR 222.22 - Scope and duration of opt-out.

Science.gov (United States)

2010-01-01

... SYSTEM FAIR CREDIT REPORTING (REGULATION V) Affiliate Marketing § 222.22 Scope and duration of opt-out.... (2) Continuing relationship—(i) In general. If the consumer establishes a continuing relationship... connection with— (A) A single continuing relationship or multiple continuing relationships that the consumer...

Forum: Making Sense of the Opt-Out Movement: "Education Next" Talks with Scott Levy and Jonah Edelman

Science.gov (United States)

Levy, Scott; Edelman, Jonah

2016-01-01

Over the past few years, students by the thousands have refused to take their state's standardized tests. This "opt-out" phenomenon has prompted debate in state legislatures and in Washington, putting states at risk of losing Title I funds. Advocates describe opt-out as a grassroots movement of parents concerned about overtesting,…

16 CFR 680.24 - Reasonable opportunity to opt out.

Science.gov (United States)

2010-01-01

..., such as by posting the notice at an Internet Web site at which the consumer has obtained a product or... conducted on an Internet Web site. The consumer is required to decide, as a necessary part of proceeding... including in a privacy notice. The opt-out notice is included in a Gramm-Leach-Bliley Act privacy notice...

40 CFR Appendix A to Subpart III... - States With Approved State Implementation Plan Revisions Concerning CAIR SO2 Opt-In Units

Science.gov (United States)

2010-07-01

... Implementation Plan Revisions Concerning CAIR SO2 Opt-In Units A Appendix A to Subpart III of Part 97 Protection... BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS CAIR SO2 Opt-in Units Pt. 97, Subpt. III... Concerning CAIR SO2 Opt-In Units 1. The following States have State Implementation Plan revisions under § 51...

Calient Networks chosen as core platform for OptIPuter

CERN Multimedia

2003-01-01

Calient Networks, a provider of intelligent all-optical switching systems and software, will team with the California Institute for Telecommunications and Information Technology (Cal-(IT)2) and the University of Illinois at Chicago (UIC) on development of the "OptIPuter,". This is a powerful distributed cyber-infrastructure project designed to support data-intensive scientific research and collaboration (1/2 page).

12 CFR 222.21 - Affiliate marketing opt-out and exceptions.

Science.gov (United States)

2010-01-01

... solicitation for marketing purposes to a consumer with whom you have a pre-existing business relationship; (2... 12 Banks and Banking 3 2010-01-01 2010-01-01 false Affiliate marketing opt-out and exceptions. 222... FEDERAL RESERVE SYSTEM FAIR CREDIT REPORTING (REGULATION V) Affiliate Marketing § 222.21 Affiliate...

17 CFR 248.121 - Affiliate marketing opt out and exceptions.

Science.gov (United States)

2010-04-01

... business relationship with the consumer. (b) Making marketing solicitations—(1) In general. For purposes of... 17 Commodity and Securities Exchanges 3 2010-04-01 2010-04-01 false Affiliate marketing opt out... COMMISSION (CONTINUED) REGULATIONS S-P AND S-AM Regulation S-AM: Limitations on Affiliate Marketing § 248.121...

Activity of OPT-80, a novel macrocycle, compared with those of eight other agents against selected anaerobic species.

Science.gov (United States)

Credito, Kim L; Appelbaum, Peter C

2004-11-01

Agar dilution MIC was used to compare activities of OPT-80, linezolid, vancomycin, teicoplanin, quinupristin/dalfopristin, amoxicillin/clavulanate, imipenem, clindamycin, and metronidazole against 350 gram-positive and -negative anaerobes. OPT-80 was active against gram-positive strains only, especially Clostridium spp. (85 strains tested, including 21 strains of C. difficile), with MICs ranging between

OptMAVEn--a new framework for the de novo design of antibody variable region models targeting specific antigen epitopes.

Directory of Open Access Journals (Sweden)

Tong Li

Full Text Available Antibody-based therapeutics provides novel and efficacious treatments for a number of diseases. Traditional experimental approaches for designing therapeutic antibodies rely on raising antibodies against a target antigen in an immunized animal or directed evolution of antibodies with low affinity for the desired antigen. However, these methods remain time consuming, cannot target a specific epitope and do not lead to broad design principles informing other studies. Computational design methods can overcome some of these limitations by using biophysics models to rationally select antibody parts that maximize affinity for a target antigen epitope. This has been addressed to some extend by OptCDR for the design of complementary determining regions. Here, we extend this earlier contribution by addressing the de novo design of a model of the entire antibody variable region against a given antigen epitope while safeguarding for immunogenicity (Optimal Method for Antibody Variable region Engineering, OptMAVEn. OptMAVEn simulates in silico the in vivo steps of antibody generation and evolution, and is capable of capturing the critical structural features responsible for affinity maturation of antibodies. In addition, a humanization procedure was developed and incorporated into OptMAVEn to minimize the potential immunogenicity of the designed antibody models. As case studies, OptMAVEn was applied to design models of neutralizing antibodies targeting influenza hemagglutinin and HIV gp120. For both HA and gp120, novel computational antibody models with numerous interactions with their target epitopes were generated. The observed rates of mutations and types of amino acid changes during in silico affinity maturation are consistent with what has been observed during in vivo affinity maturation. The results demonstrate that OptMAVEn can efficiently generate diverse computational antibody models with both optimized binding affinity to antigens and reduced

Ethical issues surrounding the provider initiated opt--Out prenatal HIV screening practice in Sub-Saharan Africa: a literature review.

Science.gov (United States)

Bain, Luchuo Engelbert; Dierickx, Kris; Hens, Kristien

2015-10-24

Prevention of mother to child transmission of HIV remains a key public health priority in most developing countries. The provider Initiated Opt - Out Prenatal HIV Screening Approach, recommended by the World Health Organization (WHO) lately has been adopted and translated into policy in most Sub - Saharan African countries. To better ascertain the ethical reasons for or against the use of this approach, we carried out a literature review of the ethics literature. Papers published in English and French Languages between 1990 and 2015 from the following data bases were searched: Pubmed, Cochrane literature, Embase, Cinhal, Web of Science and Google Scholar. After screening from 302 identified relevant articles, 21 articles were retained for the critical review. Most authors considered this approach ethically justifiable due to its potential benefits to the mother, foetus and society (Beneficence). The breaching of respect for autonomy was considered acceptable on the grounds of libertarian paternalism. Most authors considered the Opt - Out approach to be less stigmatizing than the Opt - In. The main arguments against the Opt - Out approach were: non respect of patient autonomy, informed consent becoming a meaningless concept and the HIV test becoming compulsory, risk of losing trust in health care providers, neglect of social and psychological implications of doing an HIV test, risk of aggravation of stigma if all tested patients are not properly cared for and neglect of sociocultural peculiarities. The Opt - Out approach could be counterproductive in case gender sensitive issues within the various sociocultural representations are neglected, and actions to offer holistic care to all women who shall potentially test positive for HIV were not effectively ascertained. The Provider Initiated Opt - Out Prenatal HIV Screening option remains ethically acceptable, but deserves caution, active monitoring and evaluation within the translation of this approach into to practice.

12 CFR 717.25 - Reasonable and simple methods of opting out.

Science.gov (United States)

2010-01-01

... simple methods for exercising an opt-out right do not include— (i) Requiring the consumer to write his or... out. (a) In general. You must not use eligibility information about a consumer that you receive from an affiliate to make a solicitation to the consumer about your products or services, unless the...

Optimization of Simulated Inventory Systems : OptQuest and Alternatives

OpenAIRE

Kleijnen, J.P.C.; Wan, J.

2006-01-01

This article illustrates simulation optimization through an (s, S) inventory manage- ment system. In this system, the goal function to be minimized is the expected value of speci…c inventory costs. Moreover, speci…c constraints must be satis…ed for some random simulation responses, namely the service or …ll rate, and for some determin- istic simulation inputs, namely the constraint s OptQuest method. The optimal...

Efficacy and safety of fidaxomicin compared with oral vancomycin for the treatment of adults with Clostridium difficile-associated diarrhea: data from the OPT-80-003 and OPT-80-004 studies.

Science.gov (United States)

Chen, Luke F; Anderson, Deverick J

2012-06-01

Clostridium difficile is emerging as one of the most important and devastating pathogens affecting hospitalized populations around the world. The incidence of C. difficile infection is increasing and disease severity is worsening. Thus, an effective alternative to metronidazole and oral vancomycin is urgently needed. Two Phase III trials, OPT-80-003 and OPT-80-004, showed that oral fidaxomicin for 10 days was noninferior compared with treatment with oral vancomycin among adult patients with toxin-positive C. difficile-associated diarrhea (CDAD). Furthermore, fidaxomicin was associated with a lower rate of recurrence of CDAD within 4 weeks of completion of therapy. The safety and tolerability of fidaxomicin was consistent with earlier studies and established that fidaxomicin is an efficacious and well-tolerated treatment option for CDAD. Despite these potential advantages, the cost-effectiveness of this expensive agent remains poorly understood.

The modification of hybrid method of ant colony optimization, particle swarm optimization and 3-OPT algorithm in traveling salesman problem

Science.gov (United States)

Hertono, G. F.; Ubadah; Handari, B. D.

2018-03-01

The traveling salesman problem (TSP) is a famous problem in finding the shortest tour to visit every vertex exactly once, except the first vertex, given a set of vertices. This paper discusses three modification methods to solve TSP by combining Ant Colony Optimization (ACO), Particle Swarm Optimization (PSO) and 3-Opt Algorithm. The ACO is used to find the solution of TSP, in which the PSO is implemented to find the best value of parameters α and β that are used in ACO.In order to reduce the total of tour length from the feasible solution obtained by ACO, then the 3-Opt will be used. In the first modification, the 3-Opt is used to reduce the total tour length from the feasible solutions obtained at each iteration, meanwhile, as the second modification, 3-Opt is used to reduce the total tour length from the entire solution obtained at every iteration. In the third modification, 3-Opt is used to reduce the total tour length from different solutions obtained at each iteration. Results are tested using 6 benchmark problems taken from TSPLIB by calculating the relative error to the best known solution as well as the running time. Among those modifications, only the second and third modification give satisfactory results except the second one needs more execution time compare to the third modifications.

Acceptability of routine offer of HIV testing (opt-out approach) among ...

African Journals Online (AJOL)

Background: With the introduction of the opt out HIV testing policy in Ghana, the HIV test is offered routinely to all pregnant women unless they decline testing. Objective: To assess acceptability of the routine offer of HIV testing antenatal clinic (ANC) clients in the Wa municipality, Ghana. Design: Cross-sectional study of 270 ...

12 CFR 41.25 - Reasonable and simple methods of opting out.

Science.gov (United States)

2010-01-01

... exercising an opt-out right do not include— (i) Requiring the consumer to write his or her own letter; (ii.... A bank must not use eligibility information about a consumer that it receives from an affiliate to make a solicitation to the consumer about its products or services, unless the consumer is provided a...

The effect of including an opt-out option in discrete choice experiments

NARCIS (Netherlands)

J. Veldwijk (Jorien); M.S. Lambooij (Mattijs); E.W. de Bekker-Grob (Esther); H.A. Smit (Henriëtte); G.A. De Wit (G. Ardine)

2014-01-01

markdownabstractObjective: to determine to what extent the inclusion of an opt-out option in a DCE may have an effect on choice behaviour and therefore might influence the attribute level estimates, the relative importance of the attributes and calculated tradeoffs. Methods: 781 Dutch Type 2

16 CFR 313.15 - Other exceptions to notice and opt out requirements.

Science.gov (United States)

2010-01-01

... consumer. (2) A consumer may revoke consent by subsequently exercising the right to opt out of future... ACTS OF CONGRESS PRIVACY OF CONSUMER FINANCIAL INFORMATION Exceptions § 313.15 Other exceptions to... at the direction of the consumer, provided that the consumer has not revoked the consent or direction...

Optical Rogue Waves: Theory and Experiments

Science.gov (United States)

Taki, M.; Mussot, A.; Kudlinski, A.; Louvergneaux, E.; Kolobov, M.

2010-05-01

In the ocean, giant waves (also called killer waves, freak or rogue waves) are extremely rare and strong events. They are not well understood yet and the conditions which favour their emergence are unclear. Very recently, it was shown that the governing equations [1] as well as the statistical properties of an optical pulse propagating inside an optical fibre [2] mimic very well these gigantic surface waves in the ocean. Here we generate both experimentally and numerically optical rogue waves in a photonic crystal fiber (microstructured fiber) with continuous wave (CW) pumps. This is relevant for establishing an analogy with rogue waves in an open ocean. After recalling fundamental rogue waves [3] known as Akhmediev breathers that are solutions of pure nonlinear Schrödinger (NLS) equation, we analytically demonstrate that a generalized NLS equation, which governs the propagation of light in the fiber, exhibits convective modulationnal instability [4]. The latter provides one of the main explanations of the optical rogue wave extreme sensitivity to noisy initial conditions at the linear stage of their formation [5]. In the highly nonlinear regime, we provide the evidence that optical rogue waves result from soliton collisions leading to the rapid appearance/disappearance of a powerful optical pulse [6]. REFERENCES [1] C. Kharif, E. Pelinovsky, and A. Slunyaev, "Rogue Waves in the ocean", Springer Berlin Heidelberg, 2009 [2] D. R. Solli, C. Ropers, P. Koonath, and B. Jalali, "Optical rogue waves" Nature 450, 1054-1058, (2008). [3] N. Akhmediev, A. Ankiewicz, and M. Taki, "Waves that appear from nowhere and disappear without a trace", Phys. Lett. A 373, 675 (2009). [4] A. Mussot, E. Louvergneaux, N. Akhmediev, F. Reynaud, Delage, and M. Taki, "Optical fiber systems are convectively unstable", Phys. Rev. Lett. 101, 113904 (2008). [5] M. Taki, A. Mussot, A. Kudlinski, E. Louvergneaux, M. Kolobov, M. Douay, "Third-order dispersion for generating optical rogue solitons

12 CFR 216.15 - Other exceptions to notice and opt out requirements.

Science.gov (United States)

2010-01-01

... insurance to the consumer. (2) A consumer may revoke consent by subsequently exercising the right to opt out... RESERVE SYSTEM PRIVACY OF CONSUMER FINANCIAL INFORMATION (REGULATION P) Exceptions § 216.15 Other... consent or at the direction of the consumer, provided that the consumer has not revoked the consent or...

12 CFR 332.15 - Other exceptions to notice and opt out requirements.

Science.gov (United States)

2010-01-01

... insurance to the consumer. (2) A consumer may revoke consent by subsequently exercising the right to opt out... STATEMENTS OF GENERAL POLICY PRIVACY OF CONSUMER FINANCIAL INFORMATION Exceptions § 332.15 Other exceptions... consent or at the direction of the consumer, provided that the consumer has not revoked the consent or...

The kids at Hamilton Elementary School: Purposes and practices for co-opting science

Science.gov (United States)

Ortiz, Loaiza

The purpose of this study was to explore youth's purposes and motivations for engaging in science through the lens of science practices. The construct of science practices allowed me to see science in youths' lives in a holistic way, shaped by social, political, historical, economic and cultural forces. The framework for understanding urban youths' science practices is grounded in the intersections of critical and feminist theory, sociocultural learning theories, especially as applied in research in urban science education, and recent work in critical literacy studies. As I explored the answers to my research questions---(1) When 5th grade youth, living in predominantly Latino communities struggling with urban poverty, engage in science how and why do they co-opt science in ways that result in changes in participation in science? (2) What are the science practices that facilitate youths' coopting of science? And how are those practices framed by context (school, out-of-school), content (LiFE curriculum), and funds of knowledge? (3) In what ways are science practices expressions of youths' scientific literacy? And (4) In what ways do youth use science practices as tools for expressing identities and agency?---I engaged in feminist ethnography with embedded case studies. Data were collected in 2004 in school and in out of school settings. I recorded numerous informal conversations, interviews, and observations both during after-school and students' regular science and non-science classes. Findings describe how and why students co-opted science for purposes that make sense for their lives. These purposes included gaining and activating resources, building and maintaining social relationships, bridging home and school knowledge, positioning themselves with authority, and constructing science identities. Findings also explored what practices facilitated youth's co-opting of science. I highlighted three practices: making ideas public, storytelling and prioritizing and

Can a Repeated Opt-Out Reminder mitigate hypothetical bias in discrete choice experiments?

DEFF Research Database (Denmark)

Alemu, Mohammed Hussen; Olsen, Søren Bøye

2018-01-01

In this paper, we test whether a Repeated Opt-Out Reminder (ROOR) can mitigate hypothetical bias in stated discrete choice experiments (DCE). The data originate from a field experiment concerning consumer preferences for a novel food product made from cricket flour. Utilising a between...

k-OptForce: integrating kinetics with flux balance analysis for strain design.

Directory of Open Access Journals (Sweden)

Anupam Chowdhury

2014-02-01

Full Text Available Computational strain design protocols aim at the system-wide identification of intervention strategies for the enhanced production of biochemicals in microorganisms. Existing approaches relying solely on stoichiometry and rudimentary constraint-based regulation overlook the effects of metabolite concentrations and substrate-level enzyme regulation while identifying metabolic interventions. In this paper, we introduce k-OptForce, which integrates the available kinetic descriptions of metabolic steps with stoichiometric models to sharpen the prediction of intervention strategies for improving the bio-production of a chemical of interest. It enables identification of a minimal set of interventions comprised of both enzymatic parameter changes (for reactions with available kinetics and reaction flux changes (for reactions with only stoichiometric information. Application of k-OptForce to the overproduction of L-serine in E. coli and triacetic acid lactone (TAL in S. cerevisiae revealed that the identified interventions tend to cause less dramatic rearrangements of the flux distribution so as not to violate concentration bounds. In some cases the incorporation of kinetic information leads to the need for additional interventions as kinetic expressions render stoichiometry-only derived interventions infeasible by violating concentration bounds, whereas in other cases the kinetic expressions impart flux changes that favor the overproduction of the target product thereby requiring fewer direct interventions. A sensitivity analysis on metabolite concentrations shows that the required number of interventions can be significantly affected by changing the imposed bounds on metabolite concentrations. Furthermore, k-OptForce was capable of finding non-intuitive interventions aiming at alleviating the substrate-level inhibition of key enzymes in order to enhance the flux towards the product of interest, which cannot be captured by stoichiometry-alone analysis

16 CFR 680.23 - Contents of opt-out notice; consolidated and equivalent notices.

Science.gov (United States)

2010-01-01

... equivalent notices. 680.23 Section 680.23 Commercial Practices FEDERAL TRADE COMMISSION THE FAIR CREDIT REPORTING ACT AFFILIATE MARKETING § 680.23 Contents of opt-out notice; consolidated and equivalent notices... receiving marketing than is required by this part, the requirements of this section may be satisfied by...

12 CFR 717.23 - Contents of opt-out notice; consolidated and equivalent notices.

Science.gov (United States)

2010-01-01

... AFFECTING CREDIT UNIONS FAIR CREDIT REPORTING Affiliate Marketing § 717.23 Contents of opt-out notice..., conspicuous, and concise, and must accurately disclose: (i) The name of the affiliate(s) providing the notice. If the notice is provided jointly by multiple affiliates and each affiliate shares a common name...

Opting out of an ever closer union

DEFF Research Database (Denmark)

Adler-Nissen, Rebecca

2011-01-01

How is sovereignty managed in the EU? This paper investigates the relationship between sovereignty and European integration through the prism of national opt-outs from EU treaties, addressing an apparent contradiction in contemporary European governance: the contrasting processes of integration...... and differentiation. On the one hand, European integration is increasing as states transfer sovereign competencies to the EU. On the other hand, we see a multitude of differentiation processes through which member states choose to disengage from the EU polity by negotiating exemptions or derogations. Drawing...... on Pierre Bourdieu’s political sociology, the paper argues that to understand how sovereignty is exercised and interpreted in the EU, it is necessary to focus not only on the constitutive and regulative dimensions of sovereignty, but equally on the practice dimension. This entails an exploration of how...

Opt-out of Voluntary HIV Testing: A Singapore Hospital's Experience

OpenAIRE

Chua, Arlene C.; Leo, Yee Sin; Cavailler, Philippe; Chu, Christine; Ng, Aloysius; Ng, Oon Tek; Krishnan, Prabha

2012-01-01

INTRODUCTION: Since 2008, the Singapore Ministry of Health (MOH) has expanded HIV testing by increasing anonymous HIV test sites, as well as issuing a directive to hospitals to offer routine voluntary opt out inpatient HIV testing. We reviewed this program implemented at the end of 2008 at Tan Tock Seng Hospital (TTSH), the second largest acute care general hospital in Singapore. METHODS AND FINDINGS: From January 2009 to December 2010, all inpatients aged greater or equal than 21 years were ...

12 CFR 571.23 - Contents of opt-out notice; consolidated and equivalent notices.

Science.gov (United States)

2010-01-01

... TREASURY FAIR CREDIT REPORTING Affiliate Marketing § 571.23 Contents of opt-out notice; consolidated and... concise, and must accurately disclose: (i) The name of the affiliate(s) providing the notice. If the notice is provided jointly by multiple affiliates and each affiliate shares a common name, such as “ABC...

The gastropod shell has been co-opted to kill parasitic nematodes.

Science.gov (United States)

Rae, R

2017-07-06

Exoskeletons have evolved 18 times independently over 550 MYA and are essential for the success of the Gastropoda. The gastropod shell shows a vast array of different sizes, shapes and structures, and is made of conchiolin and calcium carbonate, which provides protection from predators and extreme environmental conditions. Here, I report that the gastropod shell has another function and has been co-opted as a defense system to encase and kill parasitic nematodes. Upon infection, cells on the inner layer of the shell adhere to the nematode cuticle, swarm over its body and fuse it to the inside of the shell. Shells of wild Cepaea nemoralis, C. hortensis and Cornu aspersum from around the U.K. are heavily infected with several nematode species including Caenorhabditis elegans. By examining conchology collections I show that nematodes are permanently fixed in shells for hundreds of years and that nematode encapsulation is a pleisomorphic trait, prevalent in both the achatinoid and non-achatinoid clades of the Stylommatophora (and slugs and shelled slugs), which diverged 90-130 MYA. Taken together, these results show that the shell also evolved to kill parasitic nematodes and this is the only example of an exoskeleton that has been co-opted as an immune system.

Long-Term Safety and Effectiveness of the “OptEase” Vena Cava Filter

International Nuclear Information System (INIS)

Kalva, Sanjeeva P.; Marentis, Theodore C.; Yeddula, Kalpana; Somarouthu, Bhanusupriya; Wicky, Stephan; Stecker, Michael S.

2011-01-01

Purpose: To assess the long-term safety and effectiveness of the OptEase inferior vena cava (IVC) filter. Materials and Methods: In this Institutional Review Board-approved, retrospective study, we reviewed data of 71 patients who received an OptEase filter at our institution from 2002 to 2007. Thirty-nine (55%) patients had symptoms of venous thromboembolism before filter placement. The indications for filter included contraindication to anticoagulation in 31 (44%) patients, prophylaxis against pulmonary embolism (PE) in 29 (41%) patients, and failure of anticoagulation in 11 (15%) patients. Procedure-related complications, such as symptomatic post-filter PE, deep venous thrombosis (DVT), IVC occlusion, and incidental imaging-evident filter-related complications, were recorded. Safety was assessed by the occurrence of filter-related complications during placement and follow-up. Effectiveness was assessed by the occurrence of post-filter PE. Results: Sixty-five (92%) filters were placed under fluoroscopy, and 6 (8%) were placed using intravascular ultrasound guidance. Seventy (99%) filters were placed successfully. Seven (10%) filters were placed in the suprarenal cava. Retrieval was attempted in 14 (20%) patients, and 12 filters were successfully retrieved. Clinical follow-up was available for 20 ± 21 months. Symptoms of postfilter PE and DVT occurred in 15% (n = 11) and 10% (n = 7) patients, respectively. None of these patients had computed tomography (CT)-proven PE, and only one had ultrasound-proven new DVT. One patient had symptomatic IVC occlusion. Follow-up abdominal CT in 20 patients showed thrombus in the filter in two of them. There were no instances of filter migration, filter tilt, or caval wall penetration. Conclusion: The OptEase filter appears to have an acceptable long-term safety profile. The filter was effective against PE.

Opting out of the peaceful use of nuclear power in Germany. A promising special approach in the European context?

International Nuclear Information System (INIS)

Buedenbender, Martin

2009-01-01

Nuclear power is in the focus of politics and public attention in Germany not only because of the federal elections. Again and again, voices are heard which doubt the decision taken in 2000 to opt out of the use of nuclear power. The change in parliamentary majority in favor of the alliance of CDU/CSU and FDP as a result of the elections on September 27 is leading to another review of the opt-out decision, as the three parties in their platforms expressed themselves in favor of extending nuclear power plant life. This makes a stocktaking exercise of all salient arguments imperative at the present juncture. The perspective in that case should not be restricted to national aspects but include especially the influence of the European dimension of the subject. Present political positions in the 27 EU countries indicate a renaissance of nuclear power. Numerous countries, such as Italy, Sweden, Poland or the United Kingdom, revoked their historic opt-out decisions, are using nuclear power for the first time, or want to expand greatly the nuclear share in their electricity generation mix. All 3 European agencies with clear majorities advocate the extensive use of nuclear power as a long-term component of the mix of energy resources. Germany, with its decision to opt out of the use of nuclear power, is part of a minority. Being part of a European electricity market which will grow together more and more closely up to complete integration, Germany will always be supplied electricity from nuclear sources in the long run. This will be true irrespective of nuclear power plants being operated in the country. So, shutting down German nuclear power plants will not achieve the goals of nuclear opponents but merely give rise to additional challenges in power technology in an effort to ensure Germany's electricity supply. For this reason, the new German federal government should revoke the decision to opt out of the peaceful use of nuclear power. (orig.)

A 10-year population based study of 'opt-out' HIV testing of tuberculosis patients in Alberta, Canada: national implications.

Directory of Open Access Journals (Sweden)

Richard Long

Full Text Available Compliance with the recommendation that all tuberculosis (TB patients be tested for human immunodeficiency virus (HIV has not yet been achieved in Canada or globally.The experience of "opt-out" HIV testing of TB patients in the Province of Alberta, Canada is described over a 10-year period, 2003-2012. Testing rates are reported before and after the introduction of the "opt-out" approach. Risk factors for HIV seropositivity are described and demographic, clinical and laboratory characteristics of TB patients who were newly diagnosed versus previously diagnosed with HIV are compared. Genotypic clusters, defined as groups of two or more cases whose isolates of Mycobacterium tuberculosis had identical DNA fingerprints over the 10-year period or within 2 years of one another, were analyzed for their ability to predict HIV co-infection.HIV testing rates were 26% before and 90% after the introduction of "opt-out" testing. During the "opt-out" testing years those 64 years of age at diagnosis were less likely to have been tested. In those tested the prevalence of HIV was 5.6%. In the age group 15-64 years, risk factors for HIV were: age (35-64 years, Canadian-born Aboriginal or foreign-born sub-Saharan African origin, and combined respiratory and non-respiratory disease. Compared to TB patients previously known to be HIV positive, TB patients newly discovered to be HIV positive had more advanced HIV disease (lower CD4 counts; higher viral loads at diagnosis. Large cluster size was associated with Aboriginal ancestry. Cluster size predicted HIV co-infection in Aboriginal peoples when clusters included all cases reported over 10 years but not when clusters included cases reported within 2 years of one another."Opt-out" HIV testing of TB patients is effective and well received. Universal HIV testing of TB patients (>80% of patients tested has immediate (patients and longer-term (TB/HIV program planning benefits.

Victims, vectors and villains: are those who opt out of vaccination morally responsible for the deaths of others?

Science.gov (United States)

Jamrozik, Euzebiusz; Handfield, Toby; Selgelid, Michael J

2016-12-01

Mass vaccination has been a successful public health strategy for many contagious diseases. The immunity of the vaccinated also protects others who cannot be safely or effectively vaccinated-including infants and the immunosuppressed. When vaccination rates fall, diseases like measles can rapidly resurge in a population. Those who cannot be vaccinated for medical reasons are at the highest risk of severe disease and death. They thus may bear the burden of others' freedom to opt out of vaccination. It is often asked whether it is legitimate for states to adopt and enforce mandatory universal vaccination. Yet this neglects a related question: are those who opt out, where it is permitted, morally responsible when others are harmed or die as a result of their decision? In this article, we argue that individuals who opt out of vaccination are morally responsible for resultant harms to others. Using measles as our main example, we demonstrate the ways in which opting out of vaccination can result in a significant risk of harm and death to others, especially infants and the immunosuppressed. We argue that imposing these risks without good justification is blameworthy and examine ways of reaching a coherent understanding of individual moral responsibility for harms in the context of the collective action required for disease transmission. Finally, we consider several objections to this view, provide counterarguments and suggest morally permissible alternatives to mandatory universal vaccination including controlled infection, self-imposed social isolation and financial penalties for refusal to vaccinate. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Evolution/Creationism Controversy: Analysis of Past and Current Policies in Public Schools and the Practice of Allowing Students to Opt Out of Learning Evolution Concepts

Science.gov (United States)

Speake, Jacquelyn Hoffmann

2011-07-01

Recent anti-evolution legislation, in the form of Academic Freedom bills, has been introduced in many state legislatures over the last three years. The language in the proposed Academic Freedom bills may allow different interpretations of what can be taught in the science classrooms, and possibly spur parents to take advantage of their perceived parental rights to request their child be opted-out of class when the scientific theory of evolution is taught. Five research questions guided the analysis of participant responses to questions and perception statements focusing on secondary school administrators' actions, perceptions, and awareness as they relate to their decision to allow or not allow a student to opt out of academics, specifically evolution, through the collection of data using a web-based survey. Opt out policies are typically invoked to excuse students from activities to which they or their parents may have religious objections (Scott & Branch, 2008). Florida statutes allow parents to opt out their child from human sexuality and animal dissection. The population consisted of 281 Florida public secondary school administrators, who were divided into two subgroups based on whether they have allowed or would allow a student to opt out of evolution, or have not allowed or would not allow a student to opt out of class when the scientific theory of evolution is taught. Results found that over 70% of the administrators who completed the survey have allowed or would allow parents to opt out their child from learning about the scientific theory of evolution. There was a significant relationship between the decision to allow opt out and the following variables: (a) Free and Reduced Lunch population, (b) grade level served, (c) support for teaching evolution and alternative theories, and (d) the perception that parent rights supersede state statute requiring students to learn evolution. In Florida, any scientific concept that is based on empirical evidence is

Is opting out of the peaceful uses of nuclear power a responsible approach to take?

International Nuclear Information System (INIS)

Becker, K.

1999-01-01

This was the topic of an Expert Meeting arranged by the VDI-Gesellschaft fuer Energietechnik at the Berlin Palace Hotel on September 28-29, 1999 and attended by roughly one hundred experts, almost exclusively from Germany. The meeting was organized to examine the economic impact of Germany's sole opting out of a high technology in the face of a growing worldwide energy requirement, and whether this approach will allow the objectives of carbon dioxide reduction to be achieved in the interest of climate protection. The detailed points discussed at the meeting included the economic consequences for Germany arising from the country's opting out of the use of nuclear power; the preservation of competence in nuclear technology; the future role of nuclear power in the EU; the energy options existing for climate protection. In addition, political discussions were held with representatives of the political parties. (orig.) [de

17 CFR 248.13 - Exception to opt out requirements for service providers and joint marketing.

Science.gov (United States)

2010-04-01

... include marketing of your own products or services or marketing of financial products or services offered... requirements for service providers and joint marketing. 248.13 Section 248.13 Commodity and Securities... Consumer Financial Information and Safeguarding Personal Information Exceptions § 248.13 Exception to opt...

Opt-Out Patient Navigation to Improve Breast and Cervical Cancer Screening Among Homeless Women.

Science.gov (United States)

Asgary, Ramin; Naderi, Ramesh; Wisnivesky, Juan

2017-09-01

A patient navigation model was implemented to improve breast and cervical cancer screening among women who were homeless in five shelters and shelter clinics in New York City in 2014. Navigation consisted of opt-out screening to eligible women; cancer health and screening education; scheduling and following up for screening completion, obtaining, and communicating results to patients and providers; and care coordination with social services organizations. Women (n = 162, aged 21-74, 58% black) completed mammogram (88%) and Pap testing (83%) from baselines of 59% and 50%, respectively. There was no association between mental health or substance abuse and screening completion. Adjusted analysis showed a significant association between refusing/missing Pap testing and older age (odds ratio [OR] 1.12, 95% confidence interval [CI] 1.04-1.20); independent predictors of mammogram included more pregnancies (OR 0.57, 95% CI 0.37-0.88) and older age (OR 0.84, 95% CI 0.79-0.90). Opt-out patient navigation is feasible and effective and may mitigate multilevel barriers to cancer screening among women with unstable housing.

Vanishing vaccinations: why are so many Americans opting out of vaccinating their children?

Science.gov (United States)

Calandrillo, Steve P

2004-01-01

Vaccinations against life-threatening diseases are one of the greatest public health achievements in history. Literally millions of premature deaths have been prevented, and countless more children have been saved from disfiguring illness. While vaccinations carry unavoidable risks, the medical, social and economic benefits they confer have led all fifty states to enact compulsory childhood vaccination laws to stop the spread of preventable diseases. Today, however, vaccines are becoming a victim of their success--many individuals have never witnessed the debilitating diseases that vaccines protect against, allowing complacency toward immunization requirements to build. Antivaccination sentiment is growing fast in the United States, in large part due to the controversial and hotly disputed link between immunizations and autism. The internet worsens fears regarding vaccination safety, as at least a dozen websites publish alarming information about the risks of vaccines. Increasing numbers of parents are refusing immunizations for their children and seeking legally sanctioned exemptions instead, apparently fearing vaccines more than the underlying diseases that they protect against. A variety of factors are at play: religious and philosophical beliefs, freedom and individualism, misinformation about risk, and overperception of risk. State legislatures and health departments now face a difficult challenge: respecting individual rights and freedoms while also safeguarding the public welfare. Nearly all states allow vaccination exemptions for religious reasons and a growing number provide "philosophical" opt-outs as well. However, in all but a handful of jurisdictions, neither objection is seriously documented or verified. Often, the law requires a parent to do no more than simply check a box indicating she does not wish her child to receive immunizations. The problem is exacerbated by financial incentives schools have to encourage students to opt out of vaccinations

Objective Provision Tree (OPT) in sodium cooled fast reactors; Objective Provision Tree (OPT) en reactores rapidos refrigerados por sodio. Aplicacion a la funcion de seguridad de evacuacion de calor residual

Energy Technology Data Exchange (ETDEWEB)

Queral, C.; Montero-Mayorga, J.; Gonzalez-Cadelo, J.

2013-07-01

Application to the safety function of residual heat removal As part of the project {sup S}afety Assessment for Reactor of GEN-IV (SARGEN IV) has been implemented the methodology ISAM from the IAEA to the safety assessment of new sodium reactor designs. Within the ISAM, a new tool to facilitate this assessment is the Objective Provision Tree (OPT) which documents the provisions necessary for each of the levels of defense in depth, as well as for each critical function of security. Due to the design innovations that have sodium reactors, the evaluation of safety and licensing of these reactors requires special considerations. In this work we have analyzed the mechanisms of failure of the safety function concerning the evacuation of waste heat, and have been proposed different provisions for each of the first three levels of defense in depth. The main result of this work is reflected in the elaboration of the OPTs, one for each of the first three levels of defense in depth for the safety of evacuation of residual heat function. These trees represent in a schematic way the provisions necessary to comply with the objectives of each level which are respectively: 1) deviations from normal operation, 2) control of abnormal operation and fault detection and 3) incidental control.

The OptIC Data Assimilation Intercomparison: A Statistical Critique

Science.gov (United States)

Enting, I. G.; Clisby, N.

2008-12-01

The development of improved terrestrial carbon models has assumed great importance because of concerns about significant climate-to-carbon feedback processes. The complexity of the interactions leads to considerable difficulties in the process of model calibration. The OptIC intercomparison explored some aspects of model calibration, using an idealised terrestrial carbon model. Participants were invited to estimate model parameters in various cases defined by specified time series of the model state, with various forms of added noise. The study identified the crucial importance of the choice of cost function. The present analysis revisits the OptIC study, by considering it as an exercise in statistical estimation. This treats the observations as random variables. Consequently parameter estimates, â, based on observations will also be random variables whose distribution is known as the 'sampling distribution'. Key questions for any specific case are: Are departures from â/a_true =1 indication of bias or sampling error? Under what circumstance are uncertainty estimates (of Var[â]) reliable? We consider cases where the estimate is obtained by minimising a cost function, ΘX. Assuming that we know the true form of ℓ, the log likelihood, there are three different characterisations of uncertainty that should be distinguished: (i) The uncertainty from maximum-likelihood estimates, corresponding (either exactly or asymptotically) to the Cramer-Rao bound. In a realistic calibration situation, we won't be able to determine this because the 'true' form of the likelihood is unknown. (ii) The actual uncertainty associated with using a particular cost function. If the true noise distribution is known, this can be calculated in simple cases and determined from simulations in more complicated cases. (iii) The 'formal uncertainty' based on assuming (usually incorrectly) that ΘX is the true likelihood. In the first stage of the analysis, the distinctions are illustrated by

Economic impact of the Commission's 'opt-out' proposal on the use of approved GM crops

NARCIS (Netherlands)

Hoste, R.; Wagenberg, van C.P.A.; Wijnands, J.H.M.

2015-01-01

The European Commission proposed the opportunity for individual EU Member States to restrict or prohibit the use of GMOs in food or feed on their territory (a national ‘opt-out’). The economic impact on individual sectors of the feed and food chain (the vegetable oil and meal industry, trade, animal

Digest - International Conference on Optical and Millimeter Wave Propagation and Scattering in the Atmosphere Held in Florence, Italy on May 27-30, 1986.

Science.gov (United States)

1986-05-01

Physics Division, Graduate School of Applied Science and Technology, The Hebrew University of Jerusalem , Jerusalem , ISRAEL Introduction The correlation...A.M. Yaqlom, J. Math. Phys., 1, 48, 1960. 8] G. Eichmann , J.O.S.A., 61, 161, 1971. 9) D. Eve, Proc. Roy. Soc. (London), A347, 405, 1976. 10] L.S...the Turbulent Atmosphere on Wave Propagation, Israel Program for Scientific Translations, Jerusalem , 1971. 123 Fried, D.L., J. Opt. Soc. Am. 55, 1427

Opt-Out Parental Consent in Online Surveys: Ethical Considerations.

Science.gov (United States)

Harris, Jane; Porcellato, Lorna

2018-07-01

This article aims to foster discussion and debate around seeking parental consent from young people recruited online. The growth of social media, particularly for young people, has led to increased interest in young people's online activities as both a research topic and recruitment setting. In a health-related study, which sought to recruit young people aged 13 to 18 years old from YouTuber fan communities to an online survey, the question arose of how parental consent could be sought from young people below 16 when no link existed between researcher and parents/guardians. A practical strategy is proposed which combines novel communication methods for participant information, opt-out online consent and age verification to address this issue. Strengths and limitations of these approaches are discussed.

Users manual for Opt-MS : local methods for simplicial mesh smoothing and untangling.

Energy Technology Data Exchange (ETDEWEB)

Freitag, L.

1999-07-20

Creating meshes containing good-quality elements is a challenging, yet critical, problem facing computational scientists today. Several researchers have shown that the size of the mesh, the shape of the elements within that mesh, and their relationship to the physical application of interest can profoundly affect the efficiency and accuracy of many numerical approximation techniques. If the application contains anisotropic physics, the mesh can be improved by considering both local characteristics of the approximate application solution and the geometry of the computational domain. If the application is isotropic, regularly shaped elements in the mesh reduce the discretization error, and the mesh can be improved a priori by considering geometric criteria only. The Opt-MS package provides several local node point smoothing techniques that improve elements in the mesh by adjusting grid point location using geometric, criteria. The package is easy to use; only three subroutine calls are required for the user to begin using the software. The package is also flexible; the user may change the technique, function, or dimension of the problem at any time during the mesh smoothing process. Opt-MS is designed to interface with C and C++ codes, ad examples for both two-and three-dimensional meshes are provided.

Which Factors Drive the Decision to Boycott and Opt Out of Research Rankings?

OpenAIRE

Michael Berlemann; Justus Haucap

2012-01-01

This note contains an empirical analysis of the decision of German-speaking business scholars to boycott and opt out of the best known research ranking of business scholars, initiated and published by Germany’s largest business daily, Handelsblatt. Our analysis indicates that scientists who are more senior (already have a longer academic career) and scientists who have been either less successful or less eager to publish their research in internationally well renown journals with high impac...

Opting for co-operation

International Nuclear Information System (INIS)

1987-12-01

This report proposes a process for choosing a low-level radioactive waste management site based on the following principles: the community should volunteer and have the right to opt out of the siting process; the community should be a partner in problem-solving and decision-making throughout the process; the community should receive compensation to offset impacts and enhance local benefits; the community should have the right to select from given technical options and impact management measures; the siting task force responsible for implementation of the process must ensure that environmental safety and human health are not compromised. The Task Force recommends that: voluntary acceptance be adopted as the basic principle for the process of siting a low-level waste management facility; the emphasis given to technical assessments of options and their impacts be counterbalanced by legitimization of an active joint decision-making role for potentially affected residents; the community accepting the facility be compensated in a way that offsets all costs and leaves the community better off than it was previously; the concepts of improved management and long-term storage, with the ability to monitor and retrieve wastes, become the immediate objectives for the handling of low-level radioactive waste accumulations. The Task Force suggests a classification system for wastes based on the fundamental properties of the wastes and their management requirements rather than on their origins and administrative affiliations. The Atomic Energy Control Board should assume a more proactive role in defining and establishing acceptable approaches to low-level radioactive waste management. The Task Force did not discover any evidence that there is a health threat from existing low-level waste accumulations in Ontario. Carbon 14 may pose a particular problem, and there should be further research into the requirements of carbon 14

OptFlux: an open-source software platform for in silico metabolic engineering

DEFF Research Database (Denmark)

Rocha, I.; Maia, P.; Evangelista, P.

2010-01-01

to address industrial goals. However, the use of these methods has been restricted to bioinformaticians or other expert researchers. The main aim of this work is, therefore, to provide a user-friendly computational tool for Metabolic Engineering applications. Results: OptFlux is an open-source and modular...... available a number of useful tools. Its open-source nature invites contributions by all those interested in making their methods available for the community. Given its plug-in based architecture it can be extended with new functionalities. Currently, several plug-ins are being developed, including network...

A voluntary deductible in health insurance: the more years you opt for it, the lower your premium?

NARCIS (Netherlands)

K.P.M. Winssen van (Kayleigh); R.C. van Kleef (Richard); W.P.M.M. van de Ven (Wynand)

2017-01-01

textabstractAdverse selection regarding a voluntary deductible (VD) in health insurance implies that insured only opt for a VD if they expect no (or few) healthcare expenses. This paper investigates two potential strategies to reduce adverse selection: (1) differentiating the premium to the duration

40 CFR 97.288 - CAIR SO2 allowance allocations to CAIR SO2 opt-in units.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 20 2010-07-01 2010-07-01 false CAIR SO2 allowance allocations to CAIR SO2 opt-in units. 97.288 Section 97.288 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS...

40 CFR 96.288 - CAIR SO2 allowance allocations to CAIR SO2 opt-in units.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 20 2010-07-01 2010-07-01 false CAIR SO2 allowance allocations to CAIR SO2 opt-in units. 96.288 Section 96.288 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR...

Correlates of HIV testing refusal among emergency department patients in the opt-out testing era.

Science.gov (United States)

Setse, Rosanna W; Maxwell, Celia J

2014-05-01

Opt-out HIV screening is recommended by the CDC for patients in all healthcare settings. We examined correlates of HIV testing refusal among urban emergency department (ED) patients. Confidential free HIV screening was offered to 32,633 ED patients in an urban tertiary care facility in Washington, DC, during May 2007-December 2011. Demographic differences in testing refusals were examined using χ(2) tests and generalized linear models. HIV testing refusal rates were 47.7 % 95 % CI (46.7-48.7), 11.7 % (11.0-12.4), 10.7 % (10.0-11.4), 16.9 % (15.9-17.9) and 26.9 % (25.6-28.2) in 2007, 2008, 2009, 2010 and 2011 respectively. Persons 33-54 years of age [adjusted prevalence ratio (APR) 1.42, (1.36-1.48)] and those ≥ 55 years [APR 1.39 (1.31-1.47)], versus 33-54 years; and females versus males [APR 1.07 (1.02-1.11)] were more likely to refuse testing. Opt-out HIV testing is feasible and sustainable in urban ED settings. Efforts are needed to encourage testing among older patients and women.

Who opts out of a project for health promotion with incentives?: Empirical research on the effect of rewards to motivate persistence.

Science.gov (United States)

Okamoto, Shohei; Komamura, Kohei; Tanabe, Kai; Yokoyama, Noriko; Tsukao, Akiko; Chijiki, Shoko; Kuno, Shinya

2017-01-01

Objectives　Although providing incentives for a better lifestyle has been of increasing concern, there is insufficient evidence about its effect. Therefore, this research aims to discover new insights by verifying the effect of rewards to motivate persistence in a project for health promotion.Methods　A total of 7,622 participants of an incentivized project for health promotion (Wellness Point Project) were recruited from 6 municipalities in Japan, namely Tohoku, Chubu, Kanto, Kinki, and Chugoku, of which the 4,291 individuals who had the necessary information for estimation were analyzed. Persistence in the project was judged by whether there was information about daily steps and/or participation in some fitness classes every month for one year at most. In addition, we used the reason participants chose certain rewards in order to categorize the characteristic of rewards, and estimated opt-out hazard ratios from the project using survival time analysis. Furthermore, the estimation in the model included individual features such as age, education, status of physical activity before joining the project, lifestyles such as smoking, drinking, and so on.Results　A multivariate analysis reveals that those who had chosen a reward for regional contribution were more likely to opt out than those who had chosen a certain reward because it is close to cash. The opt-out hazard ratio was 1.63 (95% CI: 1.18-2.25) among men and 1.40 (95% CI: 1.08-1.81) among women. In addition, insufficient physical activity, smoking, working for men, and physical condition for women were associated with opt-out.Conclusions　This research verified that a reward that participants felt was close to cash, compared to the internal motivation of regional contribution, could enhance the persistence rate of the project. Moreover, it was found that not only giving incentives but also considering participants' conditions is necessary to enhance persistence.

Effectiveness of a group opt-in session on uptake and graduation rates for pulmonary rehabilitation.

Science.gov (United States)

Graves, J; Sandrey, V; Graves, T; Smith, D L

2010-08-01

Pulmonary rehabilitation (PR) is an effective intervention in the treatment of patients with chronic obstructive pulmonary disease (COPD). Unfortunately some patients offered this treatment either fail to take up the offer or fail to complete the course. Studies have indicated a number of factors influencing uptake and completion rates. We describe the introduction of an intervention, the group opt-in session (GOIS), prior to individualised baseline assessment and entry to the PR course, with the intention being to improve uptake and completion rates. A 1.5-hour-long GOIS was offered as the first face-to-face contact to all patients referred for PR. Drop-out rates at all stages of the pathway from referral to graduation were collected on 200 patients prior to the introduction of the GOIS (non-GOIS group) and compared to the first 400 patients following introduction (the GOIS group). Possible independent predictors of course uptake and completion were examined in the GOIS group. The proportion of referred patients taking up the offer of individualised baseline assessment or a GOIS was similar (75% vs. 72.2%, p value not significant [ns]). However, since in the GOIS group the opt-in session preceded the individualised baseline assessment and some patients opted-out, a smaller proportion of referred patients underwent this assessment than in the non-GOIS group (58.7% vs. 75%, p graduated in the GOIS group (87.9% vs. 76.4%, p rates due to illness were similar in both groups (8.5% pre vs. 6.8% post, ns). However, drop-out rates not due to illness were much higher in the non-GOIS group (15.1% vs. 5.3%, p graduation rates at The North Bristol Lung Centre PR Course and reduced wasted assessments. There was no effect on initial uptake. Analysis of the behaviour of patients invited to a GOIS suggested that age, lung function and travel distance were important factors influencing patient choice.

75 FR 57058 - Oregon Parks and Recreation Department Habitat Conservation Plan Along the Pacific Coast in...

Science.gov (United States)

2010-09-17

..., Newport, OR 97365; South Tillamook Branch Library, 6200 Camp St., Pacific City, OR 97135; Port Orford Public Library, 555 W. 20th St., Port Orford, Oregon 97465; Reedsport Branch Library, 395 Winchester Ave... Use e. Other Dry Sand Activities 2. Beach Management a. Public Safety b. Law Enforcement c. Boat and...

Opting For Families: Recent Trends in the Fertility of Highly Educated Women. NBER Working Paper No. 15074

Science.gov (United States)

Shang, Qingyan; Weinberg, Bruce A.

2009-01-01

Observers have argued about whether highly-educated women are opting out of their careers and for families. If so, it is natural to expect fertility to increase and, insofar as children are associated with lower employment, further declines in employment. This paper provides a comprehensive study of recent trends in the fertility of…

How to opt into the Common European Sales Law? Brief comments on the Commission's proposal for a regulation

NARCIS (Netherlands)

Hesselink, M.

2012-01-01

Unlike the actual text for the proposed Common European Sales Law (CESL), which is based on extensive preparatory work by academics, the regime for opting into the instrument, which is set out in the main text of the proposed regulation, is entirely of the European Commission's own making. The

How to opt into the Common European Sales Law? Brief comments on the Commission's proposal for a regulation

NARCIS (Netherlands)

Hesselink, M.W.; Claeys, I.; Feltkamp, R.

2013-01-01

Unlike the actual text for the proposed Common European Sales Law (CESL), which is based on extensive preparatory work by academics, the regime for opting into the instrument, which is set out in the main text of the proposed regulation, is entirely of the European Commission's own making. The

Universal opt-out screening for hepatitis C virus (HCV) within correctional facilities is an effective intervention to improve public health.

Science.gov (United States)

Morris, Meghan D; Brown, Brandon; Allen, Scott A

2017-09-11

Purpose Worldwide efforts to identify individuals infected with the hepatitis C virus (HCV) focus almost exclusively on community healthcare systems, thereby failing to reach high-risk populations and those with poor access to primary care. In the USA, community-based HCV testing policies and guidelines overlook correctional facilities, where HCV rates are believed to be as high as 40 percent. This is a missed opportunity: more than ten million Americans move through correctional facilities each year. Herein, the purpose of this paper is to examine HCV testing practices in the US correctional system, California and describe how universal opt-out HCV testing could expand early HCV detection, improve public health in correctional facilities and communities, and prove cost-effective over time. Design/methodology/approach A commentary on the value of standardizing screening programs across facilities by mandating all facilities (universal) to implement opt-out testing policies for all prisoners upon entry to the correctional facilities. Findings Current variability in facility-level testing programs results in inconsistent testing levels across correctional facilities, and therefore makes estimating the actual number of HCV-infected adults in the USA difficult. The authors argue that universal opt-out testing policies ensure earlier diagnosis of HCV among a population most affected by the disease and is more cost-effective than selective testing policies. Originality/value The commentary explores the current limitations of selective testing policies in correctional systems and provides recommendations and implications for public health and correctional organizations.

How Strong Is Europeanisation, Really? The Danish Defence Administration and the Opt-Out from the European Security and Defence Policy

DEFF Research Database (Denmark)

Olsen, Gorm Rye

2011-01-01

The article questions how strong Europeanisation is as an explanation of administrative changes in EU member states. Denmark has an opt-out from the European cooperation on defence, and, therefore, its defence administration represents a critical or a less likely case to test the Europeanisation...... thesis. The article shows that in spite of the opt-out, the administrative structures and the policy processes in the Ministry of Foreign Affairs (MFA) have adapted to the common foreign and security policy (CFSP) and the European security and defence policy (ESDP). Surprisingly, the administrative...... structures and the decision-making processes in the Ministry of Defence (MoD) have also adapted to the ESDP. The latter example emphasises the strength of top-down Europeanisation as a possible explanation of domestic administrative changes in member states. It is argued that Europeanisation per se...

Practical speed meter designs for quantum nondemolition gravitational-wave interferometers

International Nuclear Information System (INIS)

Purdue, Patricia; Chen Yanbei

2002-01-01

In the quest to develop viable designs for third-generation optical interferometric gravitational-wave detectors (e.g., LIGO-III and EURO), one strategy is to monitor the relative momentum or speed of the test-mass mirrors, rather than monitoring their relative position. A previous paper analyzed a straightforward but impractical design for a speed-meter interferometer that accomplishes this. This paper describes some practical variants of speed-meter interferometers. Like the original interferometric speed meter, these designs in principle can beat the gravitational-wave standard quantum limit (SQL) by an arbitrarily large amount, over an arbitrarily wide range of frequencies. These variants essentially consist of a Michelson interferometer plus an extra 'sloshing' cavity that sends the signal back into the interferometer with opposite phase shift, thereby cancelling the position information and leaving a net phase shift proportional to the relative velocity. In practice, the sensitivity of these variants will be limited by the maximum light power W circ circulating in the arm cavities that the mirrors can support and by the leakage of vacuum into the optical train at dissipation points. In the absence of dissipation and with squeezed vacuum (power squeeze factor e -2R ≅0.1) inserted into the output port so as to keep the circulating power down, the SQL can be beat by h/h SQL ∼√(W circ SQL e -2R /W circ ) at all frequencies below some chosen f opt ≅100 Hz. Here W circ SQL ≅800 kW(f opt /100 Hz) 3 is the power required to reach the SQL in the absence of squeezing. (However, as the power increases in this expression, the speed meter becomes more narrow band; additional power and reoptimization of some parameters are required to maintain the wide band. See Sec. III B.) Estimates are given of the amount by which vacuum leakage at dissipation points will debilitate this sensitivity; these losses are 10% or less over most of the frequency range of interest (f

eCodonOpt: a systematic computational framework for optimizing codon usage in directed evolution experiments

OpenAIRE

Moore, Gregory L.; Maranas, Costas D.

2002-01-01

We present a systematic computational framework, eCodonOpt, for designing parental DNA sequences for directed evolution experiments through codon usage optimization. Given a set of homologous parental proteins to be recombined at the DNA level, the optimal DNA sequences encoding these proteins are sought for a given diversity objective. We find that the free energy of annealing between the recombining DNA sequences is a much better descriptor of the extent of crossover formation than sequence...

Presentations from the Aeroelastic Workshop - latest results from AeroOpt

Energy Technology Data Exchange (ETDEWEB)

Hartvig Hansen, M. (ed.)

2011-10-15

This report contains the slides of the presentations at the Aeroelastic Workshop held at Risoe-DTU for the wind energy industry in Denmark on October 27, 2011. The scientific part of the agenda at this workshop was 1) Detailed and reduced models of dynamic mooring system (Anders M. Hansen). 2) Bend-twist coupling investigation in HAWC2 (Taeseong Kim). 3) Q3UIC - A new aerodynamic airfoil tool including rotational effects (Nestor R. Garcia). 4) Influence of up-scaling on loads, control and aerodynamic modeling (Helge Aa. Madsen). 5) Aerodynamic damping of lateral tower vibrations (Bjarne S. Kallesoee). 6) Open- and closed-loop aeroservoelastic analysis with HAWCStab2 (Morten H. Hansen). 7) Design and test of a thick, flatback, high-lift multielement airfoil (Frederik Zahle). The presented results are mainly obtained in the EUDP project ''Aeroelastic Optimization of MW Wind Turbines (AeroOpt)''. (Author)

Optimizing Cofactor Specificity of Oxidoreductase Enzymes for the Generation of Microbial Production Strains—OptSwap

DEFF Research Database (Denmark)

King, Zachary A.; Feist, Adam

2013-01-01

Central oxidoreductase enzymes (eg, dehydrogenases, reductases) in microbial metabolism often have preferential binding specificity for one of the two major currency metabolites NAD(H) and NADP(H). These enzyme specificities result in a division of the metabolic functionality of the currency...... specificities of oxidoreductase enzyme and complementary reaction knockouts. Using the Escherichia coli genome-scale metabolic model iJO1366, OptSwap predicted eight growth-coupled production designs with significantly greater product yields or substrate-specific productivities than designs predicted with gene...

Differential Bees Flux Balance Analysis with OptKnock for in silico microbial strains optimization.

Directory of Open Access Journals (Sweden)

Yee Wen Choon

Full Text Available Microbial strains optimization for the overproduction of desired phenotype has been a popular topic in recent years. The strains can be optimized through several techniques in the field of genetic engineering. Gene knockout is a genetic engineering technique that can engineer the metabolism of microbial cells with the objective to obtain desirable phenotypes. However, the complexities of the metabolic networks have made the process to identify the effects of genetic modification on the desirable phenotypes challenging. Furthermore, a vast number of reactions in cellular metabolism often lead to the combinatorial problem in obtaining optimal gene deletion strategy. Basically, the size of a genome-scale metabolic model is usually large. As the size of the problem increases, the computation time increases exponentially. In this paper, we propose Differential Bees Flux Balance Analysis (DBFBA with OptKnock to identify optimal gene knockout strategies for maximizing the production yield of desired phenotypes while sustaining the growth rate. This proposed method functions by improving the performance of a hybrid of Bees Algorithm and Flux Balance Analysis (BAFBA by hybridizing Differential Evolution (DE algorithm into neighborhood searching strategy of BAFBA. In addition, DBFBA is integrated with OptKnock to validate the results for improving the reliability the work. Through several experiments conducted on Escherichia coli, Bacillus subtilis, and Clostridium thermocellum as the model organisms, DBFBA has shown a better performance in terms of computational time, stability, growth rate, and production yield of desired phenotypes compared to the methods used in previous works.

Is 'Opt-Out HIV Testing' a real option among pregnant women in rural districts in Kenya?

Directory of Open Access Journals (Sweden)

Wamalwa David

2011-03-01

Full Text Available Abstract Background An 'opt-out' policy of routine HIV counseling and testing (HCT is being implemented across sub-Saharan Africa to expand prevention of mother-to-child transmission (PMTCT. Although the underlying assumption is that pregnant women in rural Africa are able to voluntarily consent to HIV testing, little is known about the reality and whether 'opt-out' HCT leads to higher completion rates of PMTCT. Factors associated with consent to HIV testing under the 'opt-out' approach were investigated through a large cross-sectional study in Kenya. Methods Observations during HIV pre-test information sessions were followed by a cross-sectional survey of 900 pregnant women in three public district hospitals carrying out PMTCT in the Busia district. Women on their first antenatal care (ANC visit during the current pregnancy were interviewed after giving blood for HIV testing but before learning their test results. Descriptive statistics and multivariate regression analysis were performed. Results Of the 900 women participating, 97% tested for HIV. Lack of testing kits was the only reason for women not being tested, i.e. nobody declined HIV testing. Despite the fact that 96% had more than four earlier pregnancies and 37% had been tested for HIV at ANC previously, only 17% of the women surveyed knew that testing was optional. Only 20% of those surveyed felt they could make an informed decision to decline HIV testing. Making an informed decision to decline HIV testing was associated with knowing that testing was optional (OR = 5.44, 95%CI 3.44-8.59, not having a stable relationship with the child's father (OR = 1.76, 95%CI 1.02-3.03, and not having discussed HIV testing with a partner before the ANC visit (OR = 2.64 95%CI 1.79-3.86. Conclusion High coverage of HIV testing appears to be achieved at the cost of pregnant women not understanding that testing is optional. Good quality HIV pre-test information is central to ensure that pregnant women

Domestic uptake of green energy promoted by opt-out tariffs

Science.gov (United States)

Ebeling, Felix; Lotz, Sebastian

2015-09-01

Motivating individuals to choose energy from sustainable sources over conventionally produced power constitutes one of the biggest policy challenges for societies. Here we present the results of a randomized controlled trial in Germany that tested the impact of default rules (that is, a type of `nudging’) on voluntary purchases of `green’ energy contracts that entirely stem from renewable resources. Setting the default choice to more expensive `green’ energy (that is, where consumers have to actively opt out if they do not want it) increased purchases of such nearly tenfold. Furthermore, county-level political preference for the green party uniquely predicted behaviour in the absence of the nudge, suggesting that default setting potentially overrules motivational aspects of green energy purchases. In follow-up experiments, we provide further evidence that the effect does not seem to be driven by unawareness. Summarizing, the present research provides an example of using behavioural science for climate change mitigation and shows alternatives to the use of subsidies or other economic incentives.

Opt-Out Panel Testing for HIV, Hepatitis B and Hepatitis C in an Urban Emergency Department: A Pilot Study.

Directory of Open Access Journals (Sweden)

Sarah O'Connell

Full Text Available Studies suggest 2 per 1000 people in Dublin are living with HIV, the level above which universal screening is advised. We aimed to assess the feasibility and acceptability of a universal opt-out HIV, Hepatitis B and Hepatitis C testing programme for Emergency Department patients and to describe the incidence and prevalence of blood-borne viruses in this population.An opt-out ED blood borne virus screening programme was piloted from March 2014 to January 2015. Patients undergoing blood sampling during routine clinical care were offered HIV 1&2 antibody/antigen assay, HBV surface antigen and HCV antibody tests. Linkage to care where necessary was co-ordinated by the study team. New diagnosis and prevalence rates were defined as the new cases per 1000 tested and number of positive tests per 1000 tested respectively.Over 45 weeks of testing, of 10,000 patient visits, 8,839 individual patient samples were available for analysis following removal of duplicates. A sustained target uptake of >50% was obtained after week 3. 97(1.09%, 44(0.49% and 447(5.05% HIV, Hepatitis B and Hepatitis C tests were positive respectively. Of these, 7(0.08%, 20(0.22% and 58(0.66% were new diagnoses of HIV, Hepatitis B and Hepatitis C respectively. The new diagnosis rate for HIV, Hepatitis B and Hepatitis C was 0.8, 2.26 and 6.5 per 1000 and study prevalence for HIV, Hepatitis B and Hepatitis C was 11.0, 5.0 and 50.5 per 1000 respectively.Opt-out blood borne viral screening was feasible and acceptable in an inner-city ED. Blood borne viral infections were prevalent in this population and newly diagnosed cases were diagnosed and linked to care. These results suggest widespread blood borne viral testing in differing clinical locations with differing population demographic risks may be warranted.

Opt-Out Panel Testing for HIV, Hepatitis B and Hepatitis C in an Urban Emergency Department: A Pilot Study.

LENUS (Irish Health Repository)

O'Connell, Sarah

2016-01-01

Studies suggest 2 per 1000 people in Dublin are living with HIV, the level above which universal screening is advised. We aimed to assess the feasibility and acceptability of a universal opt-out HIV, Hepatitis B and Hepatitis C testing programme for Emergency Department patients and to describe the incidence and prevalence of blood-borne viruses in this population.

Laser Hazards Bibliography - November 1980.

Science.gov (United States)

1980-11-01

Mohon, N., and Rodemann, A., Laser speckle for determining ametropia and accommodation response of the eye, Appl Opt, 12(4): 783-787 (April 1973). 88...Soc Am, 57: 787-797 (1967). 81. Furutsu, H., Statistical theory of wave propagation in a random medium and the irradiance distribution function, J Opt

16 CFR 316.5 - Prohibition on charging a fee or imposing other requirements on recipients who wish to opt out.

Science.gov (United States)

2010-01-01

... other than the recipient's electronic mail address and opt-out preferences, or take any other steps except sending a reply electronic mail message or visiting a single Internet Web page, in order to: (a) Use a return electronic mail address or other Internet-based mechanism, required by 15 U.S.C. 7704(a...

Well-being and associated factors among adults in the occupied Palestinian territory (oPt).

Science.gov (United States)

Harsha, Nouh; Ziq, Luay; Ghandour, Rula; Giacaman, Rita

2016-08-30

The World Health Organization (WHO) incorporated well-being into its definition of health in 1948. The significance given to this concept is due to its role in the assessment of people's quality of life and health. Using the WHO Well-being Index, we estimated well-being among adults and identified selected associated factors in the occupied Palestinian territory (oPt) using data obtained from the National Time Use Survey conducted by the Palestinian Central Bureau of Statistics (PCBS) 2012-2013 on a representative sample of persons living in the West Bank and Gaza Strip. Univariate and bivariate analyses were conducted among participants 18 years old and above. Multivariate analysis (Regression) was performed with factors found significant in cross-tabulations, using SPSS® version 20. Overall, 33.8 % (2395) of respondents reported low levels of well-being (ill-being). Neither age, nor sex, nor region were found significant in regression analysis. People who were married, working 15 h or more, with a higher standard of living, who reported participating in community, cultural, and social events, or in religious activities reported high levels of well-being. Those who reported regularly following the mass media, or living in Palestinian refugee camps reported low levels of wellbeing. Overall, about one-third of adult Palestinians reported low levels of well-being (ill-being), a finding which in itself requires attention. Marriage, employment, high living standards, community participation, and religious activities were found to be protective against ill-being. Further investigations are required to determine additional causes of ill-being in the oPt, taking into consideration the possible effects of chronic exposure to political violence on subjective well-being.

The OptIPuter microscopy demonstrator: enabling science through a transatlantic lightpath.

Science.gov (United States)

Ellisman, M; Hutton, T; Kirkland, A; Lin, A; Lin, C; Molina, T; Peltier, S; Singh, R; Tang, K; Trefethen, A E; Wallom, D C H; Xiong, X

2009-07-13

The OptIPuter microscopy demonstrator project has been designed to enable concurrent and remote usage of world-class electron microscopes located in Oxford and San Diego. The project has constructed a network consisting of microscopes and computational and data resources that are all connected by a dedicated network infrastructure using the UK Lightpath and US Starlight systems. Key science drivers include examples from both materials and biological science. The resulting system is now a permanent link between the Oxford and San Diego microscopy centres. This will form the basis of further projects between the sites and expansion of the types of systems that can be remotely controlled, including optical, as well as electron, microscopy. Other improvements will include the updating of the Microsoft cluster software to the high performance computing (HPC) server 2008, which includes the HPC basic profile implementation that will enable the development of interoperable clients.

The OptIPuter microscopy demonstrator: enabling science through a transatlantic lightpath

Science.gov (United States)

Ellisman, M.; Hutton, T.; Kirkland, A.; Lin, A.; Lin, C.; Molina, T.; Peltier, S.; Singh, R.; Tang, K.; Trefethen, A.E.; Wallom, D.C.H.; Xiong, X.

2009-01-01

The OptIPuter microscopy demonstrator project has been designed to enable concurrent and remote usage of world-class electron microscopes located in Oxford and San Diego. The project has constructed a network consisting of microscopes and computational and data resources that are all connected by a dedicated network infrastructure using the UK Lightpath and US Starlight systems. Key science drivers include examples from both materials and biological science. The resulting system is now a permanent link between the Oxford and San Diego microscopy centres. This will form the basis of further projects between the sites and expansion of the types of systems that can be remotely controlled, including optical, as well as electron, microscopy. Other improvements will include the updating of the Microsoft cluster software to the high performance computing (HPC) server 2008, which includes the HPC basic profile implementation that will enable the development of interoperable clients. PMID:19487201

Extended Huygens-Fresnel principle and optical waves propagation in turbulence: discussion.

Science.gov (United States)

Charnotskii, Mikhail

2015-07-01

Extended Huygens-Fresnel principle (EHF) currently is the most common technique used in theoretical studies of the optical propagation in turbulence. A recent review paper [J. Opt. Soc. Am. A31, 2038 (2014)JOAOD60740-323210.1364/JOSAA.31.002038] cites several dozens of papers that are exclusively based on the EHF principle. We revisit the foundations of the EHF, and show that it is burdened by very restrictive assumptions that make it valid only under weak scintillation conditions. We compare the EHF to the less-restrictive Markov approximation and show that both theories deliver identical results for the second moment of the field, rendering the EHF essentially worthless. For the fourth moment of the field, the EHF principle is accurate under weak scintillation conditions, but is known to provide erroneous results for strong scintillation conditions. In addition, since the EHF does not obey the energy conservation principle, its results cannot be accurate for scintillations of partially coherent beam waves.

OptEase and TrapEase Vena Cava Filters: A Single-Center Experience in 258 Patients

International Nuclear Information System (INIS)

Onat, Levent; Ganiyusufoglu, Ali Kursat; Mutlu, Ayhan; Sirvanci, Mustafa; Duran, Cihan; Ulusoy, Onur Levent; Hamzaoglu, Azmi

2009-01-01

We aimed to evaluate the efficacy and safety of the OptEase and TrapEase (both from Cordis, Roden, Netherlands) vena cava filters in the prevention of pulmonary embolism (PE). Between May 2004 and December 2008, OptEase (permanent/retrievable; n = 228) or TrapEase (permanent; n = 30) vena cava filters were placed in 258 patients (160 female and 98 male; mean age 62 years [range 22 to 97]). Indications were as follows: prophylaxis for PE (n = 239), contraindication for anticoagulation in the presence of PE or DVT (n = 10), and development of PE or DVT despite anticoagulation (n = 9). Medical records were retrospectively reviewed for indications, clinical results, and procedure-related complications during placement and retrieval. Clinical PE did not develop in any of the patients. However, radiologic signs of segmental PE were seen in 6 of 66 patients with follow-up imaging data. Migration or fracture of the filter or cava perforation was not seen in any of the patients. Except for a single case of asymptomatic total cava thrombosis, no thrombotic occlusion was observed. One hundred forty-one patients were scheduled to undergo filter removal; however, 17 of them were not suitable for such based on venography evaluation. Removal was attempted in 124 patients and was successful in 115 of these (mean duration of retention 11 days [range 4 to 23]). Nine filters could not be removed. Permanent/retrievable vena cava filters are safe and effective devices for PE prophylaxis and for the management of venous thromboembolism by providing the option to be left in place.

Optimized production technology (OPT), theory of constraints (TOC) og den dertil hørende økonomistyringstankegang 'Throughput Accounting (TPA)'

DEFF Research Database (Denmark)

Nielsen, Steen; Hansen, Tom Albæk

2005-01-01

Kombinationen af økonomistyring med forskellige andre funktionsområder, f.eks., indkøb, produktion, afsætning, adfærd etc., er et vigtigt område, og udgør efterhånden en del af det pensum, som repræsenteres i diverse lærebøger indenfor cost management accounting. OPT, TOC, TPA, samt også modeller...... som Just-In-Time (JIT) og Life-Cycle-Costing (LCC) vil fremover kunne give inspiration til nye måder at anskue økonomistyringen på. TOC, JIT og LCC kombineres ofte, både i relation til de mere operative beslutninger, men også i relation til virksomhedens strategiledelse. Ideen er, at også de...... separat eller i kombination. På denne måde bør de kunne støtte virksomhedens strategi og dermed den samlede lønsomhed. Hvor OPT sætter fokus på at optimere produktionen, sætter TOC og TPA fokus på udnyttelse af produktionsapparatet og på likviditeten. TPA minder på mange måder om bidragsmodellen og den...

Qualitative and quantitative assessment of the short- and long-term consequences of opting out of nuclear energy

International Nuclear Information System (INIS)

Briem, G.; Halstrick, M.; Heilemann, U.; Hillebrand, B.; Kiy, M.; Neuhaus, R.; Knieper, O.; Schmidt, H.W.; Weiss, T.

1986-08-01

A reference scenario establishes the prospective development of the energy and overall economy under status-quo conditions, i.e. assuming especially the continued use of nuclear energy, while two scenarios (alternative I: 'immediate opting out' and alternative II: 'opting out in the long term') try to assess the consequences of a shutdown of nuclear energy for the economic development of the Federal Republic of Germany. Especially, the study deals with the effects on the power industry, the ecological consequences, and the overall economic effects both in the short and long run. In all three scenarios, the development of the home consumption of electric power is first of all determined by a structure model of the entire economy. The capacity required to meet that demand and its use are calculated with the aid of a power plant model; short- and long-term cost-minimization programmes making allowance especially for fuel and capital costs from the elements from which these quantities are derived. Fuel and capital costs operate as variables in the structure model to determine the sectoral and overall economic development. The report in addition investigates separately, in partial models, the effects on the chemical industry and the branches of industry processing iron, steel, and non-ferrous metals, all of which are greatly in demand of electric power. (orig./UA) [de

Factors influencing patients with stage 5 chronic kidney disease to opt for conservative management: a practitioner research study

OpenAIRE

Johnston, Sheila; Noble, Helen

2012-01-01

Aims and objectives. This study explored decision-making experiences of patients with stage 5 chronic kidney disease when opting for conservative management of their renal failure.Background. Dialysis is an invasive treatment, and for some older patients, there is an associated treatment burden of dialysis-related symptoms. An alternative choice is conservative management, but little is known about those who make this decision and how they are supported through the process.Design. Qualitative...

Improving Public Schools through the Dissent of Parents: Opting out of Tests, Demanding Alternative Curricula, Invoking Parent Trigger Laws, and Withdrawing Entirely

Science.gov (United States)

Stitzlein, Sarah M.

2015-01-01

Some parents and caregivers, frustrated by low academic performance of their local school, emphasis on testing, or the content of the curriculum, have worked independently or formed parent groups to speak out and demand improvements. Parents and families enact solutions such as opting out of tests, developing alternative curricula, invoking parent…

The Effect of Veneer Layers on the Bending Shear Strength and Delamination of Laminated Veneer Lumber (LVL) from Oil Palm Trunk (OPT)

Science.gov (United States)

Jamaludin, M. A.; Nordin, K.; Bahari, S. A.; Ahmad, M.

2010-03-01

The aim of this study was to evaluate the effects of the number of veneer layers on the bending shear strength and delamination of Laminated Veneer Lumber (LVL) from oil palm trunk (OPT). Five (5), Six (6) and Seven (7) veneer layers of OPT LVL were manufactured. The dimension of the boards was 45 cm by 45 cm by 1.9 cm. The boards were hot pressed for 13 minutes at a pressure of 31 kgf per m2. Urea formaldehyde (UF) supplied by a local adhesive manufacturer was used as the binder for the boards. The bending shear tests consisted of the edgewise and flatwise tests, whereas the delamination test consisted of the cold and hot water boil tests. The preparation of the test specimens and tests set-up was in accordance to the Japanese Standards, JAS-1991 [1]. Six replications were used for each test. The results were analyzed by Analysis of Variance (ANOVA) using the Duncan's Multiple Range Test to test for significant differences. The results indicated that as the number of layers increased the strength also increased. All the boards passed the standard. The difference in strength between the different types of samples was significant at 95 percent confidence level. Bending shear failures were primarily in the veneers. It is possible to use the boards as light weight interior building and furniture components. Over the years, the supply of quality timber resources from the natural forest has decrease as the wood-based industry experienced rapid growth. The supply of rubberwood for the furniture industry is also decreasing as a result of increase latex price. Accordingly, OPT LVL can be an alternative or supplementary raw material for the wood-based industry.

Evolution of a Directional Wave Spectrum in a 3D Marginal Ice Zone with Random Floe Size Distribution

Science.gov (United States)

Montiel, F.; Squire, V. A.

2013-12-01

techniques are then used to solve the problem for the full MIZ. Wave attenuation data are obtained using ensemble averaging and preliminary comparisons with field experiment data will be given in the presentation. The model also offers important insights in regards to the spreading of the directional wave spectrum as it penetrates deeper into the MIZ. Cincotti, G., Gori, F., Santarsiero, M., Frezza, F., Furno, F., and Schettini, G. (1993). Plane wave expansion of cylindrical functions. Opt. Commun., 95(4):192-198. Wadhams, P., Squire, V. A., Ewing, J. A., and Pascal, R. W. (1986). The effect of the marginal ice zone on the directional wave spectrum of the ocean. J. Phys. Oceanogr., 16:358-376.

The new opt-out Dutch National Breast Implant Registry - Lessons learnt from the road to implementation.

Science.gov (United States)

Rakhorst, Hinne A; Mureau, Marc A M; Cooter, Rodney D; McNeil, John; van Hooff, Miranda; van der Hulst, René; Hommes, Juliette; Hoornweg, Marije; Moojen-Zaal, Laura; Liem, Patricia; Mathijssen, Irene M J

2017-10-01

An estimated 1-3% of all women in the Netherlands carry breast implants. Since the introduction five decades ago, problems with a variety of breast implants have emerged with direct consequences for the patients' health. Plastic surgeons worldwide reacted through campaigning for auditing on long-term implant quality, surgeon performance, and institutional outcomes in implant registries. Especially, the PIP implant scandal of 2010 demonstrated the paucity of epidemiological data and uncovered a weakness in our ability to even 'track and trace' patients. In addition, a recent report of the Dutch Institute of National Health showed a lack of compliance of 100% of breast implant producers to CE requirements. These arguments stress the need for an independent implant registry. Insufficient capture rates or dependence from the implant producers made the variety of national and international patient registries unreliable. The Dutch Breast Implant Registry (DBIR) is unique because it is an opt-out registry without the need for informed consent and thus a high capture rate. Furthermore, an estimated 95% of breast implants are implanted by board-certified plastic surgeons. Funding was received from a non-governmental organisation to increase the quality of health care in the Netherlands, and maintenance is gathered by 25 euros per implant inserted. This article describes the way the Dutch have set up their system, with special attention to the well-known hurdles of starting a patient registry. Examples include: funding, medical ethical issues, opt out system, benchmarking, quality assurance as well as governance and collaboration. The Dutch consider their experience and data shareware for others to be used globally to the benefit of patient safety and quality improvement. Copyright © 2017 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

ExRET-Opt: An automated exergy/exergoeconomic simulation framework for building energy retrofit analysis and design optimisation

International Nuclear Information System (INIS)

García Kerdan, Iván; Raslan, Rokia; Ruyssevelt, Paul; Morillón Gálvez, David

2017-01-01

Highlights: • Development of a building retrofit-oriented exergoeconomic-based optimisation tool. • A new exergoeconomic cost-benefit indicator is developed for design comparison. • Thermodynamic and thermal comfort variables used as constraints and/or objectives. • Irreversibilities and exergetic cost for end-use processes are substantially reduced. • Robust methodology that should be pursued in everyday building retrofit practice. - Abstract: Energy simulation tools have a major role in the assessment of building energy retrofit (BER) measures. Exergoeconomic analysis and optimisation is a common practice in sectors such as the power generation and chemical processes, aiding engineers to obtain more energy-efficient and cost-effective energy systems designs. ExRET-Opt, a retrofit-oriented modular-based dynamic simulation framework has been developed by embedding a comprehensive exergy/exergoeconomic calculation method into a typical open-source building energy simulation tool (EnergyPlus). The aim of this paper is to show the decomposition of ExRET-Opt by presenting modules, submodules and subroutines used for the framework’s development as well as verify the outputs with existing research data. In addition, the possibility to perform multi-objective optimisation analysis based on genetic-algorithms combined with multi-criteria decision making methods was included within the simulation framework. This addition could potentiate BER design teams to perform quick exergy/exergoeconomic optimisation, in order to find opportunities for thermodynamic improvements along the building’s active and passive energy systems. The enhanced simulation framework is tested using a primary school building as a case study. Results demonstrate that the proposed simulation framework provide users with thermodynamic efficient and cost-effective designs, even under tight thermodynamic and economic constraints, suggesting its use in everyday BER practice.

Three-dimensional freak waves and higher-order wave-wave resonances

Science.gov (United States)

Badulin, S. I.; Ivonin, D. V.; Dulov, V. A.

2012-04-01

Quite often the freak wave phenomenon is associated with the mechanism of modulational (Benjamin-Feir) instability resulted from resonances of four waves with close directions and scales. This weakly nonlinear model reflects some important features of the phenomenon and is discussing in a great number of studies as initial stage of evolution of essentially nonlinear water waves. Higher-order wave-wave resonances attract incomparably less attention. More complicated mathematics and physics explain this disregard partially only. The true reason is a lack of adequate experimental background for the study of essentially three-dimensional water wave dynamics. We start our study with the classic example of New Year Wave. Two extreme events: the famous wave 26.5 meters and one of smaller 18.5 meters height (formally, not freak) of the same record, are shown to have pronounced features of essentially three-dimensional five-wave resonant interactions. The quasi-spectra approach is used for the data analysis in order to resolve adequately frequencies near the spectral peak fp ≈ 0.057Hz and, thus, to analyze possible modulations of the dominant wave component. In terms of the quasi-spectra the above two anomalous waves show co-existence of the peak harmonic and one at frequency f5w = 3/2fp that corresponds to maximum of five-wave instability of weakly nonlinear waves. No pronounced marks of usually discussed Benjamin-Feir instability are found in the record that is easy to explain: the spectral peak frequency fp corresponds to the non-dimensional depth parameter kD ≈ 0.92 (k - wavenumber, D ≈ 70 meters - depth at the Statoil platform Draupner site) that is well below the shallow water limit of the instability kD = 1.36. A unique data collection of wave records of the Marine Hydrophysical Institute in the Katsiveli platform (Black Sea) has been analyzed in view of the above findings of possible impact of the five-wave instability on freak wave occurrence. The data cover

Comparison of individuals opting for BRCA1/2 or HNPCC genetic susceptibility testing with regard to coping, illness perceptions, illness experiences, family system characteristics and hereditary cancer distress

NARCIS (Netherlands)

van Oostrom, Iris; Meijers-Heijboer, Hanne; Duivenvoorden, Hugo J.; Brocker-Vriends, Annette H. J. T.; van Asperen, Christi J.; Sijmons, Rolf H.; Seynaeve, Caroline; Van Gool, Arthur R.; Klijn, Jan G. M.; Tibben, Aad

Objective: To study differences between individuals opting for genetic cancer susceptibility testing of a known familial BRCA1/2 and HNPCC related germline mutation. Methods: Coping, illness perceptions, experiences with cancer in relatives and family system characteristics were assessed in 271

Roadmap on optical rogue waves and extreme events

Science.gov (United States)

Akhmediev, Nail; Kibler, Bertrand; Baronio, Fabio; Belić, Milivoj; Zhong, Wei-Ping; Zhang, Yiqi; Chang, Wonkeun; Soto-Crespo, Jose M.; Vouzas, Peter; Grelu, Philippe; Lecaplain, Caroline; Hammani, K.; Rica, S.; Picozzi, A.; Tlidi, Mustapha; Panajotov, Krassimir; Mussot, Arnaud; Bendahmane, Abdelkrim; Szriftgiser, Pascal; Genty, Goery; Dudley, John; Kudlinski, Alexandre; Demircan, Ayhan; Morgner, Uwe; Amiraranashvili, Shalva; Bree, Carsten; Steinmeyer, Günter; Masoller, C.; Broderick, Neil G. R.; Runge, Antoine F. J.; Erkintalo, Miro; Residori, S.; Bortolozzo, U.; Arecchi, F. T.; Wabnitz, Stefan; Tiofack, C. G.; Coulibaly, S.; Taki, M.

2016-06-01

this point of view, a number of the scientists who work in this area of research have come together to present their research in a single review article that will greatly benefit all interested parties of this research direction. Whether the authors of this ‘roadmap’ have similar views or different from the original concept, the potential reader of the review will enrich their knowledge by encountering most of the existing views on the subject. Previously, a special issue on optical rogue waves (2013 J. Opt. 15 060201) was successful in achieving this goal but over two years have passed and more material has been published in this quickly emerging subject. Thus, it is time for a roadmap that may stimulate and encourage further research.

Predicting Long-term Ischemic Events Using Routine Clinical Parameters in Patients with Coronary Artery Disease: The OPT-CAD Risk Score.

Science.gov (United States)

Han, Yaling; Chen, Jiyan; Qiu, Miaohan; Li, Yi; Li, Jing; Feng, Yingqing; Qiu, Jian; Meng, Liang; Sun, Yihong; Tao, Guizhou; Wu, Zhaohui; Yang, Chunyu; Guo, Jincheng; Pu, Kui; Chen, Shaoliang; Wang, Xiaozeng

2018-06-05

The prognosis of patients with coronary artery disease (CAD) at hospital discharge was constantly varying, and post-discharge risk of ischemic events remain a concern. However, risk prediction tools to identify risk of ischemia for these patients has not yet been reported. We sought to develop a scoring system for predicting long-term ischemic events in CAD patients receiving antiplatelet therapy that would be beneficial in appropriate personalized decision-making for these patients. In this prospective Optimal antiPlatelet Therapy for Chinese patients with Coronary Artery Disease (OPT-CAD, NCT01735305) registry, a total of 14,032 patients with CAD receiving at least one kind of antiplatelet agent were enrolled from 107 centers across China, from January 2012 to March 2014. The risk scoring system was developed in a derivation cohort (enrolled initially 10,000 patients in the database) using a logistic regression model and was subsequently tested in a validation cohort (the last 4,032 patients). Points in risk score was assigned based on the multivariable odds ratio of each factor. Ischemic events were defined as the composite of cardiac death, myocardial infarction or stroke. Ischemic events occurred in 342 (3.4%) patients in the derivation cohort and 160 (4.0%) patients in the validation cohort during 1-year follow-up. The OPT-CAD score, ranging from 0-257 points, consist of 10 independent risk factors, including age (0-71 points), heart rates (0-36 points), hypertension (0-20 points), prior myocardial infarction (16 points), prior stroke (16 points), renal insufficient (21 points), anemia (19 points), low ejection fraction (22 points), positive cardiac troponin (23 points) and ST-segment deviation (13 points). In predicting 1-year ischemic events, the area under receiver operating characteristics curve were 0.73 and 0.72 in derivation and validation cohort, respectively. The incidences of ischemic events in low- (0-90 points), medium- (91-150 points) and

Metamaterials, from electromagnetic waves to water waves, bending waves and beyond

KAUST Repository

Dupont, G.

2015-08-04

We will review our recent work on metamaterials for different types of waves. Transposition of transform optics to water waves and bending waves on plates will be considered with potential applications of cloaking to water waves protection and anti-vibrating systems.

Impact of Wave Dragon on Wave Climate

DEFF Research Database (Denmark)

Andersen, Thomas Lykke; Tedd, James; Kramer, Morten

This report is an advisory paper for use in determining the wave dragon effects on hydrography, by considering the effect on the wave climate in the region of a wave dragon. This is to be used in the impact assessment for the Wave Dragon pre-commercial demonstrator.......This report is an advisory paper for use in determining the wave dragon effects on hydrography, by considering the effect on the wave climate in the region of a wave dragon. This is to be used in the impact assessment for the Wave Dragon pre-commercial demonstrator....

Investigation of Wave Transmission from a Floating Wave Dragon Wave Energy Converter

DEFF Research Database (Denmark)

Nørgaard, Jørgen Harck; Andersen, Thomas Lykke

2012-01-01

This paper focuses on the calibration of the MIKE21BW model against the measured wave height reduction behind a 24 kW/m Wave Dragon (WD) wave energy converter. A numerical model is used to determine the wave transmission through the floating WD in varying wave conditions. The transmission obtained...

Straitjacket or Sovereignty Shield? The Danish Opt-Out on Justice and Home Affairs and Prospects after the Treaty of Lisbon

DEFF Research Database (Denmark)

Adler-Nissen, Rebecca; Gammeltoft-Hansen, Thomas

2010-01-01

How are we to understand the perplexing and sometimes even counter-intuitive position of Denmark in relation to Justice and Home Affairs (JHA)? In this article, we attempt to go behind the many myths and misunderstandings involved and analyse the consequences of the Danish opt-out from EU......-outs. Eurosceptic politicians and media claim that protocols protect national sovereignty and may serve as an example to other member states, whereas British and Danish pro-European ministers argue that they lose political influence when they ‘are sent outside'....

Wave Equation Inversion of Skeletonized SurfaceWaves

KAUST Repository

Zhang, Zhendong

2015-08-19

We present a surface-wave inversion method that inverts for the S-wave velocity from the Rayleigh dispersion curve for the fundamental-mode. We call this wave equation inversion of skeletonized surface waves because the dispersion curve for the fundamental-mode Rayleigh wave is inverted using finite-difference solutions to the wave equation. The best match between the predicted and observed dispersion curves provides the optimal S-wave velocity model. Results with synthetic and field data illustrate the benefits and limitations of this method.

Efficient Wave Energy Amplification with Wave Reflectors

DEFF Research Database (Denmark)

Kramer, Morten Mejlhede; Frigaard, Peter Bak

2002-01-01

Wave Energy Converters (WEC's) extract wave energy from a limited area, often a single point or line even though the wave energy is generally spread out along the wave crest. By the use of wave reflectors (reflecting walls) the wave energy is effectively focused and increased to approximately 130......-140%. In the paper a procedure for calculating the efficiency and optimizing the geometry of wave reflectors are described, this by use of a 3D boundary element method. The calculations are verified by laboratory experiments and a very good agreement is found. The paper gives estimates of possible power benifit...... for different geometries of the wave reflectors and optimal geometrical design parameters are specified. On this basis inventors of WEC's can evaluate whether a specific WEC possible could benefit from wave reflectors....

Assimilation of Wave Imaging Radar Observations for Real-Time Wave-by-Wave Forecasting

Science.gov (United States)

Haller, M. C.; Simpson, A. J.; Walker, D. T.; Lynett, P. J.; Pittman, R.; Honegger, D.

2016-02-01

It has been shown in various studies that a controls system can dramatically improve Wave Energy Converter (WEC) power production by tuning the device's oscillations to the incoming wave field, as well as protect WEC devices by decoupling them in extreme wave conditions. A requirement of the most efficient controls systems is a phase-resolved, "deterministic" surface elevation profile, alerting the device to what it will experience in the near future. The current study aims to demonstrate a deterministic method of wave forecasting through the pairing of an X-Band marine radar with a predictive Mild Slope Equation (MSE) wave model. Using the radar as a remote sensing technique, the wave field up to 1-4 km surrounding a WEC device can be resolved. Individual waves within the radar scan are imaged through the contrast between high intensity wave faces and low intensity wave troughs. Using a recently developed method, radar images are inverted into the radial component of surface slope, shown in the figure provided using radar data from Newport, Oregon. Then, resolved radial slope images are assimilated into the MSE wave model. This leads to a best-fit model hindcast of the waves within the domain. The hindcast is utilized as an initial condition for wave-by-wave forecasting with a target forecast horizon of 3-5 minutes (tens of wave periods). The methodology is currently being tested with synthetic data and comparisons with field data are imminent.

Waves in geophysical fluids tsunamis, rogue waves, internal waves and internal tides

CERN Document Server

Schneider, Wilhelm; Trulsen, Karsten

2006-01-01

Waves in Geophysical Fluids describes: the forecasting and risk evaluation of tsunamis by tectonic motion, land slides, explosions, run-up, and maps the tsunami sources in the world's oceans; stochastic Monte-Carlo simulations and focusing mechanisms for rogue waves, nonlinear wave models, breather formulas, and the kinematics of the Draupner wave; the full story about the discovery of the very large oceanic internal waves, how the waves are visible from above through the signatures on the sea surface, and how to compute them; observations of energetic internal tides and hot spots from several field campaigns in all parts of the world's oceans, with interpretation of spectra. An essential work for students, scientists and engineers working with the fundamental and applied aspects of ocean waves.

[Application of an OPT model in a paediatric nursing clinical case in primary health care].

Science.gov (United States)

Rifà Ros, Rosa; Pérez Pérez, Isabel

2011-01-01

This article describes the assessment and nursing diagnostic hypothesis generation on a 10 years old child with a parietal contusion who attended the health care centre with his mother. The health centre is located in a rural area in Catalonia, and a paediatric nurse was placed in charge of the child. In the assessment and the subsequent information analysis, the nurse identified an unhealthy situation for the correct development of the child. The situation required the mother's intervention and a change in her habits and behaviours. For the approach of the case study, the OPT model (Outcome Present-state Testing) by Pesut and Herdman was used. The assessment was made by using Marjory Gordon's Functional Health Patterns assessment, and the NANDA-I nursing diagnoses taxonomy, NOC Outcomes taxonomy and NIC Interventions taxonomy was used for the diagnoses and planning. Copyright © 2010 Elsevier España, S.L. All rights reserved.

Photoelectron wave function in photoionization: plane wave or Coulomb wave?

Science.gov (United States)

Gozem, Samer; Gunina, Anastasia O; Ichino, Takatoshi; Osborn, David L; Stanton, John F; Krylov, Anna I

2015-11-19

The calculation of absolute total cross sections requires accurate wave functions of the photoelectron and of the initial and final states of the system. The essential information contained in the latter two can be condensed into a Dyson orbital. We employ correlated Dyson orbitals and test approximate treatments of the photoelectron wave function, that is, plane and Coulomb waves, by comparing computed and experimental photoionization and photodetachment spectra. We find that in anions, a plane wave treatment of the photoelectron provides a good description of photodetachment spectra. For photoionization of neutral atoms or molecules with one heavy atom, the photoelectron wave function must be treated as a Coulomb wave to account for the interaction of the photoelectron with the +1 charge of the ionized core. For larger molecules, the best agreement with experiment is often achieved by using a Coulomb wave with a partial (effective) charge smaller than unity. This likely derives from the fact that the effective charge at the centroid of the Dyson orbital, which serves as the origin of the spherical wave expansion, is smaller than the total charge of a polyatomic cation. The results suggest that accurate molecular photoionization cross sections can be computed with a modified central potential model that accounts for the nonspherical charge distribution of the core by adjusting the charge in the center of the expansion.

Assimilation of Wave Imaging Radar Observations for Real-time Wave-by-Wave Forecasting

Energy Technology Data Exchange (ETDEWEB)

Simpson, Alexandra [Oregon State Univ., Corvallis, OR (United States); Haller, Merrick [Oregon State Univ., Corvallis, OR (United States). School of Civil & Construction Engineering; Walker, David [SRI International, Menlo Park, CA (United States); Lynett, Pat [Univ. of Southern California, Los Angeles, CA (United States)

2017-08-29

This project addressed Topic 3: “Wave Measurement Instrumentation for Feed Forward Controls” under the FOA number DE-FOA-0000971. The overall goal of the program was to develop a phase-resolving wave forecasting technique for application to the active control of Wave Energy Conversion (WEC) devices. We have developed an approach that couples a wave imaging marine radar with a phase-resolving linear wave model for real-time wave field reconstruction and forward propagation of the wave field in space and time. The scope of the project was to develop and assess the performance of this novel forecasting system. Specific project goals were as follows: Develop and verify a fast, GPU-based (Graphical Processing Unit) wave propagation model suitable for phase-resolved computation of nearshore wave transformation over variable bathymetry; Compare the accuracy and speed of performance of the wave model against a deep water model in their ability to predict wave field transformation in the intermediate water depths (50 to 70 m) typical of planned WEC sites; Develop and implement a variational assimilation algorithm that can ingest wave imaging radar observations and estimate the time-varying wave conditions offshore of the domain of interest such that the observed wave field is best reconstructed throughout the domain and then use this to produce model forecasts for a given WEC location; Collect wave-resolving marine radar data, along with relevant in situ wave data, at a suitable wave energy test site, apply the algorithm to the field data, assess performance, and identify any necessary improvements; and Develop a production cost estimate that addresses the affordability of the wave forecasting technology and include in the Final Report. The developed forecasting algorithm (“Wavecast”) was evaluated for both speed and accuracy against a substantial synthetic dataset. Early in the project, performance tests definitively demonstrated that the system was capable of

Wave fronts of electromagnetic cyclotron harmonic waves

International Nuclear Information System (INIS)

Ohnuma, T.; Watanabe, T.

1982-01-01

In an inhomogeneous high-density magnetized plasma, the spatial properties of the wave fronts and ray trajectories of electromagnetic ordinary and extraordinary cyclotron harmonic waves are investigated. Those waves which are radiated from a local source are found to have wave fronts which are almost parallel to the magnetic field. Also, the reflective properties of the electromagnetic cyclotron harmonic waves are confirmed

Wave Equation Inversion of Skeletonized SurfaceWaves

KAUST Repository

Zhang, Zhendong; Liu, Yike; Schuster, Gerard T.

2015-01-01

We present a surface-wave inversion method that inverts for the S-wave velocity from the Rayleigh dispersion curve for the fundamental-mode. We call this wave equation inversion of skeletonized surface waves because the dispersion curve

Wave-particle dualism of spiral waves dynamics.

Science.gov (United States)

Biktasheva, I V; Biktashev, V N

2003-02-01

We demonstrate and explain a wave-particle dualism of such classical macroscopic phenomena as spiral waves in active media. That means although spiral waves appear as nonlocal processes involving the whole medium, they respond to small perturbations as effectively localized entities. The dualism appears as an emergent property of a nonlinear field and is mathematically expressed in terms of the spiral waves response functions, which are essentially nonzero only in the vicinity of the spiral wave core. Knowledge of the response functions allows quantitatively accurate prediction of the spiral wave drift due to small perturbations of any nature, which makes them as fundamental characteristics for spiral waves as mass is for the condensed matter.

CMS-Wave

Science.gov (United States)

2015-10-30

Coastal Inlets Research Program CMS -Wave CMS -Wave is a two-dimensional spectral wind-wave generation and transformation model that employs a forward...marching, finite-difference method to solve the wave action conservation equation. Capabilities of CMS -Wave include wave shoaling, refraction... CMS -Wave can be used in either on a half- or full-plane mode, with primary waves propagating from the seaward boundary toward shore. It can

Infragravity Waves Produced by Wave Groups on Beaches

Institute of Scientific and Technical Information of China (English)

邹志利; 常梅

2003-01-01

The generation of low frequency waves by a single or double wave groups incident upon two plane beaches with the slope of 1/40 and 1/100 is investigated experimentally and numerically. A new type of wave maker signal is used to generate the groups, allowing the bound long wave (set-down) to be included in the group. The experiments show that the low frequency wave is generated during breaking and propagation to the shoreline of the wave group. This process of generation and propagation of low frequency waves is simulated numerically by solving the short-wave averaged mass and momentum conservation equations. The computed and measured results are in good agreement. The mechanism of generation of low frequency waves in the surf zone is examined and discussed.

Thermal-grating contributions to degenerate four-wave mixing in nitric oxide

International Nuclear Information System (INIS)

Danehy, P.M.; Paul, P.H.; Farrow, R.L.

1995-01-01

We report investigations of degenerate four-wave mixing (DFWM) line intensities in the A 2 Σ + left-arrow X 2 Π electronic transitions of nitric oxide. Contributions from population gratings (spatially varying perturbations in the level populations of absorbing species) and thermal gratings (spatially varying perturbations in the overall density) were distinguished and compared by several experimental and analytical techniques. For small quantities of nitric oxide in a strongly quenching buffer gas (carbon dioxide), we found that thermal-grating contributions dominated at room temperature for gas pressures of ∼0.5 atm and higher. In a nearly nonquenching buffer (nitrogen) the population-grating mechanism dominated at pressures of ∼1.0 atm and lower. At higher temperatures in an atmospheric-pressure methane/air flame, population gratings of nitric oxide also dominated. We propose a simple model for the ratio of thermal- to population-grating scattering intensities that varies as P 4 T -4.4 . Preliminary investigations of the temperature dependence and detailed studies of the pressure dependence are in agreement with this model. Measurements of the temporal evolution and the peak intensity of isolated thermal-grating signals are in detailed agreement with calculations based on a linearized hydrodynamic model [J. Opt. Soc. Am. B 12, 384 (1995)]. copyright 1995 Optical Society of America

The ISAM Tool “Objective Provision Tree (OPT)”, for the Identification of the Design Basis and he Construction of the Safety Architecture

Energy Technology Data Exchange (ETDEWEB)

Fiorini, G.L., E-mail: gian-luigi.fiorini@orange.fr; Ammirabile, L., E-mail: luca.ammirabile@ec.europa.eu [European Commission - Joint Research Centre Institute for Energy and Transport (Belgium); Ranguelova, V., E-mail: vesselina.ranguelova@ec.europa.eu [European Commission - Joint Research Centre Headquarters, Brussels (Belgium)

2014-10-15

The design of the safety architecture of innovative as well as the assessment of existing nuclear systems needs to integrate the constraints related to the safety principles, requirements and objectives. Among these constraints, the compliance of the installation’s architecture with the principles of Defence in Depth (DiD), and its different levels, is certainly one of the most structuring. Defence in depth is the key to achieve safety robustness, thereby helping to ensure that nuclear systems do not exhibit any particularly dominant risk vulnerability. To help designers of innovative systems to correctly implement the defence-in-depth, or to assess how well the latter has been applied for existing reactor systems, the Objection-Provision Tree (OPT) methodology, which is part of the Integrated Safety Assessment Methodology (ISAM) promoted by the Generation IV Risk and Safety Working Group (GIF/RSWG), is suggested as a useful tool to complement the required traditional deterministic and probabilistic safety assessments. The document recalls the content of the OPT method and gives some details for its implementation, including for the systematic identification of the initiating events to be considered in designing the system. This step is essential especially for new systems for which there is no sufficient operational to support their design. The interactions with other tools (e.g. Failure Mode and Effect Analyses (FMEA) or ISAM Tools) are also commented. (author)

Evaluating Effects of Stressors from Marine and Hydrokinetic Energy

Energy Technology Data Exchange (ETDEWEB)

Copping, Andrea E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Blake, Kara M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Hanna, Luke A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Brandt, Charles A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Ward, Jeffrey A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Brandenberger, Jill M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Gill, Gary A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Carlson, Thomas J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Elster, Jennifer L. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Jones, Mark E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Watson, Bruce E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Jepsen, Richard A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Metzinger, Kurt [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

2012-09-30

Potential environmental effects of marine and hydrokinetic (MHK) energy development are not well understood, yet regulatory agencies are required to make decisions in spite of substantial uncertainty about environmental impacts and their long-term consequences. An understanding of risks associated with interactions between MHK installations and aquatic receptors, including animals, habitats, and ecosystems, can help define key uncertainties and focus regulatory actions and scientific studies on interactions of most concern. During FY 2012, Pacific Northwest National Laboratory (PNNL) continued to follow project developments on the two marine and hydrokinetic projects reviewed for Environmental Risk Evaluation System (ERES) screening analysis in FY 2011: a tidal project in the Gulf of Maine using Ocean Renewable Power Company TidGenTM turbines and a wave project planned for the coast of Oregon using Aquamarine Oyster surge devices. The ERES project in FY 2012 also examined two stressor–receptor interactions previously identified through the screening process as being of high importance: 1) the toxicity effects of antifouling coatings on MHK devices on aquatic resources and 2) the risk of a physical strike encounter between an adult killer whale and an OpenHydro turbine blade. The screening-level assessment of antifouling paints and coatings was conducted for two case studies: the Snohomish County Public Utility District No. 1 (SnoPUD) tidal turbine energy project in Admiralty Inlet, Puget Sound, Washington, and the Ocean Power Technologies (OPT) wave buoy project in Reedsport, Oregon. Results suggest minimal risk to aquatic biota from antifouling coatings used on MHK devices deployed in large estuaries or open ocean environments. For the strike assessment of a Southern Resident Killer Whale (SRKW) encountering an OpenHydro tidal turbine blade, PNNL teamed with colleagues from Sandia National Laboratories (SNL) to carry out an analysis of the mechanics and

Detailed Comparisons of COMBAT Data to Wave-Optics Simulations

Science.gov (United States)

2015-10-18

is currently available. On the other hand, detailed simulation of the transmitter, atmosphere, and receiver can improve agreement and predictive...over 144 km in a Canary Islands experiment,” Appl. Opt. 51, 7374–7383, 2012. 8. R. J. Hill and S. F. Clifford. “Modified spectrum of atmospheric

Wave Dragon Wave Energy Converters Used as Coastal Protection

DEFF Research Database (Denmark)

Nørgaard, Jørgen Harck; Andersen, Thomas Lykke; Kofoed, Jens Peter

2011-01-01

This paper deals with wave energy converters used to reduce the wave height along shorelines. For this study the Wave Dragon wave energy converter is chosen. The wave height reduction from a single device has been evaluated from physical model tests in scale 1:51.8 of the 260 x 150 m, 24 kW/m model...... Spain, to evaluate the potential for reducing wave heights close the shore by means of Wave Dragons....

Electromagnetic waves in gravitational wave spacetimes

International Nuclear Information System (INIS)

Haney, M.; Bini, D.; Ortolan, A.; Fortini, P.

2013-01-01

We have considered the propagation of electromagnetic waves in a space-time representing an exact gravitational plane wave and calculated the induced changes on the four-potential field Aμ of a plane electromagnetic wave. By choosing a suitable photon round-trip in a Michelson interferometer, we have been able to identify the physical effects of the exact gravitational wave on the electromagnetic field, i.e. phase shift, change of the polarization vector, angular deflection and delay. These results have been exploited to study the response of an interferometric gravitational wave detector beyond the linear approximation of the general theory of relativity. A much more detailed examination of this problem can be found in our paper recently published in Classical and Quantum Gravity (28 (2011) 235007).

Real and virtual propagation dynamics of angular accelerating white light beams

CSIR Research Space (South Africa)

Vetter, C

2017-08-01

Full Text Available light modulators. References and links 1. H. Rubinsztein-Dunlop, A. Forbes, M. Berry, M. Dennis, D. L. Andrews, M. Mansuripur, C. Denz, C. Alpmann, P. Banzer, T. Bauer, E. Karimi, L. Marrucci, M. Padgett, M. Ritsch-Marte, N.M. Litchinitser, N. P. Bigelow...–678 (2008). 16. N. K. Efremidis and D. N. Christodoulides, “Abruptly autofocusing waves,” Opt. Lett. 35, 4045–4047 (2010). 17. R. Steiger, S. Bernet, and M. Ritsch-Marte, “Slm-based off-axis fourier filtering in microscopy with white light illumination,” Opt...

Benefits of up-wave measurements in linear short-term wave forecasting for wave energy applications

OpenAIRE

Paparella, Francesco; Monk, Kieran; Winands, Victor; Lopes, Miguel; Conley, Daniel; Ringwood, John

2014-01-01

The real-time control of wave energy converters requires the prediction of the wave elevation at the location of the device in order to maximize the power extracted from the waves. One possibility is to predict the future wave elevation by combining its past history with the spatial information coming from a sensor which measures the free surface elevation upwave of the wave energy converter. As an application example, the paper focuses on the prediction of the wave eleva...

Wave-equation Qs Inversion of Skeletonized Surface Waves

KAUST Repository

Li, Jing

2017-02-08

We present a skeletonized inversion method that inverts surface-wave data for the Qs quality factor. Similar to the inversion of dispersion curves for the S-wave velocity model, the complicated surface-wave arrivals are skeletonized as simpler data, namely the amplitude spectra of the windowed Rayleigh-wave arrivals. The optimal Qs model is the one that minimizes the difference in the peak frequencies of the predicted and observed Rayleigh wave arrivals using a gradient-based wave-equation optimization method. Solutions to the viscoelastic wave-equation are used to compute the predicted Rayleigh-wave arrivals and the misfit gradient at every iteration. This procedure, denoted as wave-equation Qs inversion (WQs), does not require the assumption of a layered model and tends to have fast and robust convergence compared to full waveform inversion (FWI). Numerical examples with synthetic and field data demonstrate that the WQs method can accurately invert for a smoothed approximation to the subsurface Qs distribution as long as the Vs model is known with sufficient accuracy.

Skeletonized wave-equation Qs tomography using surface waves

KAUST Repository

Li, Jing

2017-08-17

We present a skeletonized inversion method that inverts surface-wave data for the Qs quality factor. Similar to the inversion of dispersion curves for the S-wave velocity model, the complicated surface-wave arrivals are skeletonized as simpler data, namely the amplitude spectra of the windowed Rayleigh-wave arrivals. The optimal Qs model is then found that minimizes the difference in the peak frequencies of the predicted and observed Rayleigh wave arrivals using a gradient-based wave-equation optimization method. Solutions to the viscoelastic wave-equation are used to compute the predicted Rayleigh-wave arrivals and the misfit gradient at every iteration. This procedure, denoted as wave-equation Qs tomography (WQs), does not require the assumption of a layered model and tends to have fast and robust convergence compared to Q full waveform inversion (Q-FWI). Numerical examples with synthetic and field data demonstrate that the WQs method can accurately invert for a smoothed approximation to the subsur-face Qs distribution as long as the Vs model is known with sufficient accuracy.

Wave-equation Qs Inversion of Skeletonized Surface Waves

KAUST Repository

Li, Jing; Dutta, Gaurav; Schuster, Gerard T.

2017-01-01

We present a skeletonized inversion method that inverts surface-wave data for the Qs quality factor. Similar to the inversion of dispersion curves for the S-wave velocity model, the complicated surface-wave arrivals are skeletonized as simpler data, namely the amplitude spectra of the windowed Rayleigh-wave arrivals. The optimal Qs model is the one that minimizes the difference in the peak frequencies of the predicted and observed Rayleigh wave arrivals using a gradient-based wave-equation optimization method. Solutions to the viscoelastic wave-equation are used to compute the predicted Rayleigh-wave arrivals and the misfit gradient at every iteration. This procedure, denoted as wave-equation Qs inversion (WQs), does not require the assumption of a layered model and tends to have fast and robust convergence compared to full waveform inversion (FWI). Numerical examples with synthetic and field data demonstrate that the WQs method can accurately invert for a smoothed approximation to the subsurface Qs distribution as long as the Vs model is known with sufficient accuracy.

Nonlinear wave equation with intrinsic wave particle dualism

International Nuclear Information System (INIS)

Klein, J.J.

1976-01-01

A nonlinear wave equation derived from the sine-Gordon equation is shown to possess a variety of solutions, the most interesting of which is a solution that describes a wave packet travelling with velocity usub(e) modulating a carrier wave travelling with velocity usub(c). The envelop and carrier wave speeds agree precisely with the group and phase velocities found by de Broglie for matter waves. No spreading is exhibited by the soliton, so that it behaves exactly like a particle in classical mechanics. Moreover, the classically computed energy E of the disturbance turns out to be exactly equal to the frequency ω of the carrier wave, so that the Planck relation is automatically satisfied without postulating a particle-wave dualism. (author)

Nuclear power and the opting-out policy of the German Government. A matter of responsibility and controversy

International Nuclear Information System (INIS)

Grawe, J.; Voss, A.

2000-01-01

The article critically reviews the energy policy of the German Government and the plans for winding down nuclear power generation and instead pursue a policy for a ''green reshufflement'' of generation technologies, providing for incentives to switch to options for decentralized power generation with enhanced use of renewable energy sources. The article explains arguments against the Government's opting-out policy which were laid down in a memorandum presented to the Government by a group of five university professors, among them the authors of this article who, as experts in this domain, are aware of their responsibility as scientists and members of society and therefore explain their view of the policy issues, also referring to a recent expert opinion of the German Wissenschaftsrat (science council), which recommended to continue nuclear energy research programmes and nuclear power generation. (orig./CB) [de

Millimeter wave and terahertz wave transmission characteristics in plasma

International Nuclear Information System (INIS)

Ma Ping; Qin Long; Chen Weijun; Zhao Qing; Shi Anhua; Huang Jie

2013-01-01

An experiment was conducted on the shock tube to explore the transmission characteristics of millimeter wave and terahertz wave in high density plasmas, in order to meet the communication requirement of hypersonic vehicles during blackout. The transmission attenuation curves of millimeter wave and terahertz wave in different electron density and collision frequency were obtained. The experiment was also simulated by auxiliary differential equation finite-difference time-domain (ADE-FDTD) methods. The experimental and numerical results show that the transmission attenuation of terahertz wave in the plasma is smaller than that of millimeter wave under the same conditions. The transmission attenuation of terahertz wave in the plasma is enhanced with the increase of electron density. The terahertz wave is a promising alternative to the electromagnetic wave propagation in high density plasmas. (authors)

Wave Generation Theory

DEFF Research Database (Denmark)

Frigaard, Peter; Høgedal, Michael; Christensen, Morten

The intention of this manual is to provide some formulas and techniques which can be used for generating waves in hydraulic laboratories. Both long crested waves (2-D waves) and short crested waves (3-D waves) are considered.......The intention of this manual is to provide some formulas and techniques which can be used for generating waves in hydraulic laboratories. Both long crested waves (2-D waves) and short crested waves (3-D waves) are considered....

The wave of the future - Searching for gravity waves

International Nuclear Information System (INIS)

Goldsmith, D.

1991-01-01

Research on gravity waves conducted by such scientists as Gamov, Wheeler, Weber and Zel'dovich is discussed. Particular attention is given to current trends in the theoretical analysis of gravity waves carried out by theorists Kip Thorne and Leonid Grishchuk. The problems discussed include the search for gravity waves; calculation of the types of gravity waves; the possibility of detecting gravity waves from localized sources, e.g., from the collision of two black holes in a distant galaxy or the collapse of a star, through the Laser Interferometer Gravitational Wave Observatory; and detection primordial gravity waves from the big bang

Calcium waves.

Science.gov (United States)

Jaffe, Lionel F

2008-04-12

Waves through living systems are best characterized by their speeds at 20 degrees C. These speeds vary from those of calcium action potentials to those of ultraslow ones which move at 1-10 and/or 10-20 nm s(-1). All such waves are known or inferred to be calcium waves. The two classes of calcium waves which include ones with important morphogenetic effects are slow waves that move at 0.2-2 microm s(-1) and ultraslow ones. Both may be propagated by cycles in which the entry of calcium through the plasma membrane induces subsurface contraction. This contraction opens nearby stretch-sensitive calcium channels. Calcium entry through these channels propagates the calcium wave. Many slow waves are seen as waves of indentation. Some are considered to act via cellular peristalsis; for example, those which seem to drive the germ plasm to the vegetal pole of the Xenopus egg. Other good examples of morphogenetic slow waves are ones through fertilizing maize eggs, through developing barnacle eggs and through axolotl embryos during neural induction. Good examples of ultraslow morphogenetic waves are ones during inversion in developing Volvox embryos and across developing Drosophila eye discs. Morphogenetic waves may be best pursued by imaging their calcium with aequorins.

Fundamental modes of new dispersive SH-waves in ...

Indian Academy of Sciences (India)

[3] M Fiebig, V V Pavlov and R V Pisarev, J. Opt. Soc. Am. B 22(1), 96 (2005). [4] T Kimura, Ann. Rev. Condens. Matter Phys. 3(1), 93 (2012). [5] Ch-S Park and Sh Priya, Advances in condensed matter physics (Hindawi Publishing. Corporation, 2012) Vol. 2012, 12 pages. [6] R C Pullar, Prog. Mater. Sci. 57(7), 1191 (2012).

Prototype Testing of the Wave Energy Converter Wave Dragon

DEFF Research Database (Denmark)

Kofoed, Jens Peter; Frigaard, Peter; Friis-Madsen, Erik

2006-01-01

The Wave Dragon is an offshore wave energy converter of the overtopping type. It consists of two wave reflectors focusing the incoming waves towards a ramp, a reservoir for collecting the overtopping water and a number of hydro turbines for converting the pressure head into power. In the period...... from 1998 to 2001 extensive wave tank testing on a scale model was carried at Aalborg University. Then, a 57!27 m wide and 237 tonnes heavy (incl. ballast) prototype of the Wave Dragon, placed in Nissum Bredning, Denmark, was grid connected in May 2003 as the world’s first offshore wave energy...... converter. The prototype is fully equipped with hydro turbines and automatic control systems, and is instrumented in order to monitor power production, wave climate, forces in mooring lines, stresses in the structure and movements of the Wave Dragon. In the period May 2003 to January 2005 an extensive...

Prototype Testing of the Wave Energy Converter Wave Dragon

DEFF Research Database (Denmark)

Kofoed, Jens Peter; Frigaard, Peter Bak; Friis-Madsen, Erik

2004-01-01

The Wave Dragon is an offshore wave energy converter of the overtopping type. It consists of two wave reflectors focusing the incoming waves towards a ramp, a reservoir for collecting the overtopping water and a number of hydro turbines for converting the pressure head into power. In the period...... from 1998 to 2001 extensive wave tank testing on a scale model was carried at Aalborg University. Then, a 57 x 27 m wide and 237 tonnes heavy (incl. ballast) prototype of the Wave Dragon, placed in Nissum Bredning, Denmark, was grid connected in May 2003 as the world's first offshore wave energy...... converter. The prototype is fully equipped with hydro turbines and automatic control systems, and is instrumented in order to monitor power production, wave climate, forces in mooring lines, stresses in the structure and movements of the Wave Dragon. During the last months, extensive testing has started...

Experiments on the WavePiston, Wave Energy Converter

DEFF Research Database (Denmark)

Angelelli, E.; Zanuttigh, B.; Kofoed, Jens Peter

2011-01-01

This paper analyses the performance of a new Wave Energy Converter (WEC) of the Oscillating Water Column type (OWC), named WavePiston. This near-shore floating device is composed of plates (i.e. energy collectors) sliding around a cylinder, that is placed perpendicular to the shore. Tests...... in the wave basin at Aalborg University allowed to investigate power production in the North Sea typical wave climate, with varying design parameters such as plate dimensions and their mutual distance. The power produced per meter by each collector is about the 5% of the available wave power. Experimental...... results and survivability considerations suggest that the WavePiston would be particularly suited for installations in milder seas. An example application is therefore presented in the Mediterranean Sea, off-shore the island of Sicily. In this case, each collector harvests the 10% of the available wave...

Rogue waves, rational solitons and wave turbulence theory

International Nuclear Information System (INIS)

Kibler, Bertrand; Hammani, Kamal; Michel, Claire; Finot, Christophe; Picozzi, Antonio

2011-01-01

Considering a simple one-dimensional nonlinear Schroedinger optical model, we study the existence of rogue wave events in the highly incoherent state of the system and compare them with the recently identified hierarchy of rational soliton solutions. We show that rogue waves can emerge in the genuine turbulent regime and that their coherent deterministic description provided by the rational soliton solutions is compatible with an accurate statistical description of the random wave provided by the wave turbulence theory. Furthermore, the simulations reveal that even in the weakly nonlinear regime, the nonlinearity can play a key role in the emergence of an individual rogue wave event in a turbulent environment. -- Highlights: → Rogue wave events are studied in the highly incoherent regime of interaction. → We show that rogue waves can emerge in the genuine turbulent regime. → Their coherent deterministic description is provided by the rational solutions. → It coexists with a statistical description provided of the random wave. → The nonlinearity plays a key role even in a turbulent environment.

Low Frequency Waves Detected in a Large Wave Flume under Irregular Waves with Different Grouping Factor and Combination of Regular Waves

Directory of Open Access Journals (Sweden)

Luigia Riefolo

2018-02-01

Full Text Available This paper describes a set of experiments undertaken at Universitat Politècnica de Catalunya in the large wave flume of the Maritime Engineering Laboratory. The purpose of this study is to highlight the effects of wave grouping and long-wave short-wave combinations regimes on low frequency generations. An eigen-value decomposition has been performed to discriminate low frequencies. In particular, measured eigen modes, determined through the spectral analysis, have been compared with calculated modes by means of eigen analysis. The low frequencies detection appears to confirm the dependence on groupiness of the modal amplitudes generated in the wave flume. Some evidence of the influence of low frequency waves on runup and transport patterns are shown. In particular, the generation and evolution of secondary bedforms are consistent with energy transferred between the standing wave modes.

Generating gravity waves with matter and electromagnetic waves

International Nuclear Information System (INIS)

Barrabes, C.; Hogan, P A.

2008-01-01

If a homogeneous plane lightlike shell collides head on with a homogeneous plane electromagnetic shock wave having a step-function profile then no backscattered gravitational waves are produced. We demonstrate, by explicit calculation, that if the matter is accompanied by a homogeneous plane electromagnetic shock wave with a step-function profile then backscattered gravitational waves appear after the collision

Velocity-space diffusion due to resonant wave-wave scattering of electromagnetic and electrostatic waves in a plasma

International Nuclear Information System (INIS)

Sugaya, Reija

1991-01-01

The velocity-space diffusion equation describing distortion of the velocity distribution function due to resonant wave-wave scattering of electromagnetic and electrostatic waves in an unmagnetized plasma is derived from the Vlasov-Maxwell equations by perturbation theory. The conservation laws for total energy and momentum densities of waves and particles are verified, and the time evolutions of the energy and momentum densities of particles are given in terms of the nonlinear wave-wave coupling coefficient in the kinetic wave equation. (author)

Plasma waves

CERN Document Server

Swanson, DG

1989-01-01

Plasma Waves discusses the basic development and equations for the many aspects of plasma waves. The book is organized into two major parts, examining both linear and nonlinear plasma waves in the eight chapters it encompasses. After briefly discussing the properties and applications of plasma wave, the book goes on examining the wave types in a cold, magnetized plasma and the general forms of the dispersion relation that characterize the waves and label the various types of solutions. Chapters 3 and 4 analyze the acoustic phenomena through the fluid model of plasma and the kinetic effects. Th

Experimental Study on the WavePiston Wave Energy Converter

DEFF Research Database (Denmark)

Pecher, Arthur; Kofoed, Jens Peter; Angelelli, E.

This report presents the results of an experimental study of the power performance of the WavePiston wave energy converter. It focuses mainly on evaluating the power generating capabilities of the device and the effect of the following issues: Scaling ratios PTO loading Wave height and wave period...... dependency Oblique incoming waves Distance between plates During the study, the model supplied by the client, WavePiston, has been rigorously tested as all the anticipated tests have been done thoroughly and during all tests, good quality data has been obtained from all the sensors....

Experimental Measurement of Wave Field Variations around Wave Energy Converter Arrays

Directory of Open Access Journals (Sweden)

Louise O’Boyle

2017-01-01

Full Text Available Wave energy converters (WECs inherently extract energy from incident waves. For wave energy to become a significant power provider in the future, large farms of WECs will be required. This scale of energy extraction will increase the potential for changes in the local wave field and coastal environment. Assessment of these effects is necessary to inform decisions on the layout of wave farms for optimum power output and minimum environmental impact, as well as on potential site selection. An experimental campaign to map, at high resolution, the wave field variation around arrays of 5 oscillating water column WECs and a methodology for extracting scattered and radiated waves is presented. The results highlight the importance of accounting for the full extent of the WEC behavior when assessing impacts on the wave field. The effect of radiated waves on the wave field is not immediately apparent when considering changes to the entire wave spectrum, nor when observing changes in wave climate due to scattered and radiated waves superimposed together. The results show that radiated waves may account for up to 50% of the effects on wave climate in the near field in particular operating conditions.

Upper atmospheric planetary-wave and gravity-wave observations

Science.gov (United States)

Justus, C. G.; Woodrum, A.

1973-01-01

Previously collected data on atmospheric pressure, density, temperature and winds between 25 and 200 km from sources including Meteorological Rocket Network data, ROBIN falling sphere data, grenade release and pitot tube data, meteor winds, chemical release winds, satellite data, and others were analyzed by a daily-difference method, and results on the magnitude of atmospheric perturbations interpreted as gravity waves and planetary waves are presented. Traveling planetary-wave contributions in the 25-85 km range were found to have significant height and latitudinal variation. It was found that observed gravity-wave density perturbations and wind are related to one another in the manner predicted by gravity-wave theory. It was determined that, on the average, gravity-wave energy deposition or reflection occurs at all altitudes except the 55-75 km region of the mesosphere.

Turn in matters of energy. From revolt to reform. With the latest expertises on the prospect of opting out of nuclear energy. Energie-Wende. Von der Empoerung zur Reform. Mit den neuesten Gutachten zum Ausstieg aus der Kernenergie

Energy Technology Data Exchange (ETDEWEB)

Hauff, V

1986-01-01

The book is written with an entirely personal perspective, strives to take into account the latest state of knowledge and attempts to draft a future without nuclear energy at least in outline. The individual chapters have the following headings: Thirty years of development of nuclear power: dream and nightmare; The forecasts and expert opinions on the possibility of opting out - final conclusion: it can be done and is justifiable; The approach to orderly opting out: reform of our energy system. In this chapter a 10-year plan is submitted for a realistic reform of the energy economy to: save energy, reduce environmental pollution, use mainly renewable energy sources as pillars of the energy system; and leave to future generations the choice of their own lifestyle. (HSCH).

Investigation of Wave Height Reduction behind the Wave Dragon Wave Energy Converters and Application in Santander, Spain

DEFF Research Database (Denmark)

Nørgaard, Jørgen Quvang Harck; Andersen, Thomas Lykke

This paper deals with a case study on the wave height reduction behind floating Wave Dragon wave energy converters in Santander Bay, Spain. The study is performed using the MIKE21 Boussinesq model from DHI. The Wave Dragon transmission characteristics in the numerical wave propagation model...... are based on previously performed physical model tests in scale 1:51. Typical winter storm conditions are considered in the case study together with different stiffness in the mooring system of the floating device. From the study it is found that if multiple Wave Dragons are positioned in a farm the wave...

In-tube shock wave driven by atmospheric millimeter-wave plasma

International Nuclear Information System (INIS)

Oda, Yasuhisa; Kajiwara, Ken; Takahashi, Koji; Kasugai, Atsushi; Sakamoto, Keishi; Komurasaki, Kimiya

2009-01-01

A shock wave in a tube supported by atmospheric millimeter-wave plasma is discussed. After atmospheric breakdown, the shock wave supported by the millimeter wave propagates at a constant velocity in the tube. In this study, a driving model of the millimeter-wave shock wave is proposed. The model consists of a normal shock wave supported by a propagating heat-supply area in which an ionization front is located. The flow properties predicted by the model show good agreement with the measured properties of the shock wave generated in the tube using a 170 GHz millimeter wave beam. The shock propagation velocity U shock is identical to the propagation velocity of the ionization front U ioniz when U ioniz is supersonic. Then the pressure increment at the tube end is independent of the power density. (author)

Planetary wave-gravity wave interactions during mesospheric inversion layer events

Science.gov (United States)

Ramesh, K.; Sridharan, S.; Raghunath, K.; Vijaya Bhaskara Rao, S.; Bhavani Kumar, Y.

2013-07-01

lidar temperature observations over Gadanki (13.5°N, 79.2°E) show a few mesospheric inversion layer (MIL) events during 20-25 January 2007. The zonal mean removed SABER temperature shows warm anomalies around 50°E and 275°E indicating the presence of planetary wave of zonal wave number 2. The MIL amplitudes in SABER temperature averaged for 10°N-15°N and 70°E-90°E show a clear 2 day wave modulation during 20-28 January 2007. Prior to 20 January 2007, a strong 2day wave (zonal wave number 2) is observed in the height region of 80-90 km and it gets largely suppressed during 20-26 January 2007 as the condition for vertical propagation is not favorable, though it prevails at lower heights. The 10 day mean zonal wind over Tirunelveli (8.7°N, 77.8°E) shows deceleration of eastward winds indicating the westward drag due to wave dissipation. The nightly mean MF radar observed zonal winds show the presence of alternating eastward and westward winds during the period of 20-26 January 2007. The two dimensional spectrum of Rayleigh lidar temperature observations available for the nights of 20, 22, and 24 January 2007 shows the presence of gravity wave activity with periods 18 min, 38 min, 38 min, and vertical wavelengths 6.4 km, 4.0 km, 6.4 km respectively. From the dispersion relation of gravity waves, it is inferred that these waves are internal gravity waves rather than inertia gravity waves with the horizontal phase speeds of ~40 m/s, ~37 m/s, and ~50 m/s respectively. Assuming the gravity waves are eastward propagating waves, they get absorbed only in the eastward local wind fields of the planetary wave thereby causing turbulence and eddy diffusion which can be inferred from the estimation of large drag force due to the breaking of gravity wave leading to the formation of large amplitude inversion events in alternate nights. The present study shows that, the mesospheric temperature inversion is caused mainly due to the gravity wave breaking and the inversion

Do PhDs Voluntarily Opt for Private Sector Employment? Evidence of Push and Pull Effects on Mobility Choices

DEFF Research Database (Denmark)

Pedersen, Heidi Skovgaard

2014-01-01

In Denmark, policy makers have increased admissions to PhD programs to ensure the flow of researchers into the private sector, thereby increasing knowledge transfer. However, we know little about the factors influencing the sector mobility of PhD graduates. While opting for employment...... in the private sector might be driven by personal preferences, there might also be external factors pushing PhDs to choose the private sector. This article examines the push and pull effects on mobility choices using duration models to estimate the transition rates to private sector employment. The analyses show...... that the preference for and ability to do academic science reduces transition rates to the private sector, whereas being in a research position and earnings potential are attractors to the private sector. Hence, both push and pull effects determine sector mobility. Once the initial sector choice has been made...

Adaptations of energy metabolism during cerebellar neurogenesis are co-opted in medulloblastoma.

Science.gov (United States)

Tech, Katherine; Deshmukh, Mohanish; Gershon, Timothy R

2015-01-28

Recent studies show that metabolic patterns typical of cancer cells, including aerobic glycolysis and increased lipogenesis, are not unique to malignancy, but rather originate in physiologic development. In the postnatal brain, where sufficient oxygen for energy metabolism is scrupulously maintained, neural progenitors nevertheless metabolize glucose to lactate and prioritize lipid synthesis over fatty acid oxidation. Medulloblastoma, a cancer of neural progenitors that is the most common malignant brain tumor in children, recapitulates the metabolic phenotype of brain progenitor cells. During the physiologic proliferation of neural progenitors, metabolic enzymes generally associated with malignancy, including Hexokinase 2 (Hk2) and Pyruvate kinase M2 (PkM2) configure energy metabolism to support growth. In these non-malignant cells, expression of Hk2 and PkM2 is driven by transcriptional regulators that are typically identified as oncogenes, including N-myc. Importantly, N-myc continues to drive Hk2 and PkM2 in medulloblastoma. Similarly E2F transcription factors and PPARγ function in both progenitors and medulloblastoma to optimize energy metabolism to support proliferation. These findings show that the "metabolic transformation" that is a hallmark of cancer is not specifically limited to cancer. Rather, metabolic transformation represents a co-opting of developmental programs integral to physiologic growth. Despite their physiologic origins, the molecular mechanisms that mediate metabolic transformation may nevertheless present ideal targets for novel anti-tumor therapy. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Skeletonized wave equation of surface wave dispersion inversion

KAUST Repository

Li, Jing

2016-09-06

We present the theory for wave equation inversion of dispersion curves, where the misfit function is the sum of the squared differences between the wavenumbers along the predicted and observed dispersion curves. Similar to wave-equation travel-time inversion, the complicated surface-wave arrivals in traces are skeletonized as simpler data, namely the picked dispersion curves in the (kx,ω) domain. Solutions to the elastic wave equation and an iterative optimization method are then used to invert these curves for 2D or 3D velocity models. This procedure, denoted as wave equation dispersion inversion (WD), does not require the assumption of a layered model and is less prone to the cycle skipping problems of full waveform inversion (FWI). The synthetic and field data examples demonstrate that WD can accurately reconstruct the S-wave velocity distribution in laterally heterogeneous media.

Solitary wave and periodic wave solutions for the thermally forced gravity waves in atmosphere

International Nuclear Information System (INIS)

Li Ziliang

2008-01-01

By introducing a new transformation, a new direct and unified algebraic method for constructing multiple travelling wave solutions of general nonlinear evolution equations is presented and implemented in a computer algebraic system, which extends Fan's direct algebraic method to the case when r > 4. The solutions of a first-order nonlinear ordinary differential equation with a higher degree nonlinear term and Fan's direct algebraic method of obtaining exact solutions to nonlinear partial differential equations are applied to the combined KdV-mKdV-GKdV equation, which is derived from a simple incompressible non-hydrostatic Boussinesq equation with the influence of thermal forcing and is applied to investigate internal gravity waves in the atmosphere. As a result, by taking advantage of the new first-order nonlinear ordinary differential equation with a fifth-degree nonlinear term and an eighth-degree nonlinear term, periodic wave solutions associated with the Jacobin elliptic function and the bell and kink profile solitary wave solutions are obtained under the effect of thermal forcing. Most importantly, the mechanism of propagation and generation of the periodic waves and the solitary waves is analysed in detail according to the values of the heating parameter, which show that the effect of heating in atmosphere helps to excite westerly or easterly propagating periodic internal gravity waves and internal solitary waves in atmosphere, which are affected by the local excitation structures in atmosphere. In addition, as an illustrative sample, the properties of the solitary wave solution and Jacobin periodic solution are shown by some figures under the consideration of heating interaction

Skeletonized wave-equation Qs tomography using surface waves

KAUST Repository

Li, Jing; Dutta, Gaurav; Schuster, Gerard T.

2017-01-01

We present a skeletonized inversion method that inverts surface-wave data for the Qs quality factor. Similar to the inversion of dispersion curves for the S-wave velocity model, the complicated surface-wave arrivals are skeletonized as simpler data

UK National Data Guardian for Health and Care’s Review of Data Security: Trust, better security and opt-outs

Directory of Open Access Journals (Sweden)

Tom Chan

2016-12-01

Full Text Available Sharing health and social care data is essential to the delivery of high quality health care as well as disease surveillance, public health, and for conducting research. However, these societal benefits may be constrained by privacy and data protection principles. Hence, societies are striving to find a balance between the two competing public interests. Whilst the spread of IT advancements in recent decades has increased the demand for an increased privacy and data protection in many ways health is a special case. UK, are adopting guidelines, codes of conduct and regulatory instruments aimed to implement privacy principles into practical settings and enhance public trust. Accordingly, in 2015, the UK National Data Guardian (NDG requested to conduct a further review of data protection, referred to as Caldicott 3.  The scope of this review is to strengthen data security standards and confidentiality. It also proposes a consent system based on an “opt-out” model rather than on “opt-in. Across Europe as well as internationally the privacy-health data sharing balance is not fixed.  In Europe enactment of the new EU Data Protection Regulation in 2016 constitute a major breakthrough, which is likely to have a profound effect on European countries and beyond.  In Australia and across North America different ways are being sought to balance out these twin requirements of a modern society - to preserve privacy alongside affording high quality health care for an ageing population.   Whilst in the UK privacy legal framework remains complex and fragmented into different layers of legislation, which may negatively impact on both the rights to privacy and health the UK is at the forefront in the uptake of international and EU privacy and data protection principles. And, if the privacy regime were reorganised in a more comprehensive manner, it could be used as a sound implementation model for other countries.

Wave Tank Studies of Phase Velocities of Short Wind Waves

Science.gov (United States)

Ermakov, S.; Sergievskaya, I.; Shchegolkov, Yu.

Wave tank studies of phase velocities of short wind waves have been carried out using Ka-band radar and an Optical Spectrum Analyser. The phase velocities were retrieved from measured radar and optical Doppler shifts, taking into account measurements of surface drift velocities. The dispersion relationship was studied in centimetre (cm)- and millimetre(mm)-scale wavelength ranges at different fetches and wind speeds, both for a clean water surface and for water covered with surfactant films. It is ob- tained that the phase velocities do not follow the dispersion relation of linear capillary- gravity waves, increasing with fetch and, therefore, depending on phase velocities of dominant decimetre (dm)-centimetre-scale wind waves. One thus can conclude that nonlinear cm-mm-scale harmonics bound to the dominant wind waves and propagat- ing with the phase velocities of the decimetric waves are present in the wind wave spectrum. The resulting phase velocities of short wind waves are determined by re- lation between free and bound waves. The relative intensity of the bound waves in the spectrum of short wind waves is estimated. It is shown that this relation depends strongly on the surfactant concentration, because the damping effect due to films is different for free and bound waves; this results to changes of phase velocities of wind waves in the presence of surfactant films. This work was supported by MOD, UK via DERA Winfrith (Project ISTC 1774P) and by RFBR (Project 02-05-65102).

Ion Acoustic Waves in the Presence of Electron Plasma Waves

DEFF Research Database (Denmark)

Michelsen, Poul; Pécseli, Hans; Juul Rasmussen, Jens

1977-01-01

Long-wavelength ion acoustic waves in the presence of propagating short-wavelength electron plasma waves are examined. The influence of the high frequency oscillations is to decrease the phase velocity and the damping distance of the ion wave.......Long-wavelength ion acoustic waves in the presence of propagating short-wavelength electron plasma waves are examined. The influence of the high frequency oscillations is to decrease the phase velocity and the damping distance of the ion wave....

Wave-particle interaction in the Faraday waves.

Science.gov (United States)

Francois, N; Xia, H; Punzmann, H; Shats, M

2015-10-01

Wave motion in disordered Faraday waves is analysed in terms of oscillons or quasi-particles. The motion of these oscillons is measured using particle tracking tools and it is compared with the motion of fluid particles on the water surface. Both the real floating particles and the oscillons, representing the collective fluid motion, show Brownian-type dispersion exhibiting ballistic and diffusive mean squared displacement at short and long times, respectively. While the floating particles motion has been previously explained in the context of two-dimensional turbulence driven by Faraday waves, no theoretical description exists for the random walk type motion of oscillons. It is found that the r.m.s velocity ⟨μ̃(osc)⟩(rms) of oscillons is directly related to the turbulent r.m.s. velocity ⟨μ̃⟩(rms) of the fluid particles in a broad range of vertical accelerations. The measured ⟨μ̃(osc)⟩(rms) accurately explains the broadening of the frequency spectra of the surface elevation observed in disordered Faraday waves. These results suggest that 2D turbulence is the driving force behind both the randomization of the oscillons motion and the resulting broadening of the wave frequency spectra. The coupling between wave motion and hydrodynamic turbulence demonstrated here offers new perspectives for predicting complex fluid transport from the knowledge of wave field spectra and vice versa.

On the interaction of small-scale linear waves with nonlinear solitary waves

Science.gov (United States)

Xu, Chengzhu; Stastna, Marek

2017-04-01

In the study of environmental and geophysical fluid flows, linear wave theory is well developed and its application has been considered for phenomena of various length and time scales. However, due to the nonlinear nature of fluid flows, in many cases results predicted by linear theory do not agree with observations. One of such cases is internal wave dynamics. While small-amplitude wave motion may be approximated by linear theory, large amplitude waves tend to be solitary-like. In some cases, when the wave is highly nonlinear, even weakly nonlinear theories fail to predict the wave properties correctly. We study the interaction of small-scale linear waves with nonlinear solitary waves using highly accurate pseudo spectral simulations that begin with a fully nonlinear solitary wave and a train of small-amplitude waves initialized from linear waves. The solitary wave then interacts with the linear waves through either an overtaking collision or a head-on collision. During the collision, there is a net energy transfer from the linear wave train to the solitary wave, resulting in an increase in the kinetic energy carried by the solitary wave and a phase shift of the solitary wave with respect to a freely propagating solitary wave. At the same time the linear waves are greatly reduced in amplitude. The percentage of energy transferred depends primarily on the wavelength of the linear waves. We found that after one full collision cycle, the longest waves may retain as much as 90% of the kinetic energy they had initially, while the shortest waves lose almost all of their initial energy. We also found that a head-on collision is more efficient in destroying the linear waves than an overtaking collision. On the other hand, the initial amplitude of the linear waves has very little impact on the percentage of energy that can be transferred to the solitary wave. Because of the nonlinearity of the solitary wave, these results provide us some insight into wave-mean flow

Is Green better than Blue? The Danish JHA opt-out and the Unilateral attempt to attrack highly skilled labour

DEFF Research Database (Denmark)

Wind, Marlene; Adamo, Silvia

2015-01-01

In 20–30 years Denmark will, just like the rest of the EU, be in need of an increasing number of highly skilled workers from outside the EU to sustain its welfare society. While the EU has adopted a common Blue Card aiming at making it possible for foreign workers to live and work in most of the EU......, Denmark has, due to its opt-out in Justice and Home Affairs, chosen its own Green Card Scheme. This article looks into this choice and compares the recent Danish attempt to attract high skilled workers with the Blue Card directive. It analyses the differences and similarities between the two schemes...... and investigates why initiatives to attract highly skilled workers have not been successful at either the Danish nor the European level....

Interaction between electromagnetic waves and plasma waves in motional plasma

International Nuclear Information System (INIS)

Chen, S. Y.; Gao, M.; Tang, C. J.; Peng, X. D.

2009-01-01

The electromagnetic wave (EM wave) behavior and the electromagnetic instability caused by the interaction between an EM wave and a plasma wave in motional plasma are studied. The dispersion relation of EM waves and the dielectric tensor of motional plasma are derived by magnetohydrodynamics, and the wave phenomenon in motional plasma is displayed. As a result, the electromagnetic instability, which is excited by the interaction between the EM waves and the plasma waves, is revealed. The mechanism of the instability is the coupling between high frequency electromagnetic field and the transverse electron oscillation derived from the deflection of longitudinal electron oscillation due to self-magnetic field. The present research is useful with regard to the new type of plasma radiation source, ion-focusing accelerator, and plasma diagnostic technique.

Quasitravelling waves

International Nuclear Information System (INIS)

Beklaryan, Leva A

2011-01-01

A finite difference analogue of the wave equation with potential perturbation is investigated, which simulates the behaviour of an infinite rod under the action of an external longitudinal force field. For a homogeneous rod, describing solutions of travelling wave type is equivalent to describing the full space of classical solutions to an induced one-parameter family of functional differential equations of point type, with the characteristic of the travelling wave as parameter. For an inhomogeneous rod, the space of solutions of travelling wave type is trivial, and their 'proper' extension is defined as solutions of 'quasitravelling' wave type. By contrast to the case of a homogeneous rod, describing the solutions of quasitravelling wave type is equivalent to describing the quotient of the full space of impulsive solutions to an induced one-parameter family of point-type functional differential equations by an equivalence relation connected with the definition of solutions of quasitravelling wave type. Stability of stationary solutions is analyzed. Bibliography: 9 titles.

Wave turbulence

Energy Technology Data Exchange (ETDEWEB)

Nazarenko, Sergey [Warwick Univ., Coventry (United Kingdom). Mathematics Inst.

2011-07-01

Wave Turbulence refers to the statistical theory of weakly nonlinear dispersive waves. There is a wide and growing spectrum of physical applications, ranging from sea waves, to plasma waves, to superfluid turbulence, to nonlinear optics and Bose-Einstein condensates. Beyond the fundamentals the book thus also covers new developments such as the interaction of random waves with coherent structures (vortices, solitons, wave breaks), inverse cascades leading to condensation and the transitions between weak and strong turbulence, turbulence intermittency as well as finite system size effects, such as ''frozen'' turbulence, discrete wave resonances and avalanche-type energy cascades. This book is an outgrow of several lectures courses held by the author and, as a result, written and structured rather as a graduate text than a monograph, with many exercises and solutions offered along the way. The present compact description primarily addresses students and non-specialist researchers wishing to enter and work in this field. (orig.)

Parametric decay of lower hybrid wave into drift waves

International Nuclear Information System (INIS)

Sanuki, Heiji.

1976-12-01

A dispersion relation describing the parametric decay of a lower hybrid wave into an electrostatic drift wave and a drift Alfven wave is derived for an inhomogeneous magnetized plasma. Particularly the stimulated scattering of a drift Alfven wave in such a plasma was investigated in detail. The resonance backscattering instability is found to yield the minimum threshold. (auth.)

Colliding almost-plane gravitational waves: Colliding plane waves and general properties of almost-plane-wave spacetimes

International Nuclear Information System (INIS)

Yurtsever, U.

1988-01-01

It is well known that when two precisely plane-symmetric gravitational waves propagating in an otherwise flat background collide, they focus each other so strongly as to produce a curvature singularity. This paper is the first of several devoted to almost-plane gravitational waves and their collisions. Such waves are more realistic than plane waves in having a finite but very large transverse size. In this paper we review some crucial features of the well-known exact solutions for colliding plane waves and we argue that one of these features, the breakdown of ''local inextendibility'' can be regarded as nongeneric. We then introduce a new framework for analyzing general colliding plane-wave spacetimes; we give an alternative proof of a theorem due to Tipler implying the existence of singularities in all generic colliding plane-wave solutions; and we discuss the fact that the recently constructed Chandrasekhar-Xanthopoulos colliding plane-wave solutions are not strictly plane symmetric and thus do not satisfy the conditions and the conclusion of Tipler's theorem

Gravitational Waves

Energy Technology Data Exchange (ETDEWEB)

Miller, Jonah Maxwell [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2017-10-18

This report has slides on Gravitational Waves; Pound and Rebka: A Shocking Fact; Light is a Ruler; Gravity is the Curvature of Spacetime; Gravitational Waves Made Simple; How a Gravitational Wave Affects Stuff Here; LIGO; This Detection: Neutron Stars; What the Gravitational Wave Looks Like; The Sound of Merging Neutron Stars; Neutron Star Mergers: More than GWs; The Radioactive Cloud; The Kilonova; and finally Summary, Multimessenger Astronomy.

Propagation of nonlinear ion acoustic wave with generation of long-wavelength waves

International Nuclear Information System (INIS)

Ohsawa, Yukiharu; Kamimura, Tetsuo

1978-01-01

The nonlinear propagation of the wave packet of an ion acoustic wave with wavenumber k 0 asymptotically equals k sub(De) (the electron Debye wavenumber) is investigated by computer simulations. From the wave packet of the ion acoustic wave, waves with long wavelengths are observed to be produced within a few periods for the amplitude oscillation of the original wave packet. These waves are generated in the region where the original wave packet exists. Their characteristic wavelength is of the order of the length of the wave packet, and their propagation velocity is almost equal to the ion acoustic speed. The long-wavelength waves thus produced strongly affect the nonlinear evolution of the original wave packet. (auth.)

WAVE-E: The WAter Vapour European-Explorer Mission

Science.gov (United States)

Jimenez-LLuva, David; Deiml, Michael; Pavesi, Sara

2017-04-01

In the last decade, stratosphere-troposphere coupling processes in the Upper Troposphere Lower Stratosphere (UTLS) have been increasingly recognized to severely impact surface climate and high-impact weather phenomena. Weakened stratospheric circumpolar jets have been linked to worldwide extreme temperature and high-precipitation events, while anomalously strong stratospheric jets can lead to an increase in surface winds and tropical cyclone intensity. Moreover, stratospheric water vapor has been identified as an important forcing for global decadal surface climate change. In the past years, operational weather forecast and climate models have adapted a high vertical resolution in the UTLS region in order to capture the dynamical processes occurring in this highly stratified region. However, there is an evident lack of available measurements in the UTLS region to consistently support these models and further improve process understanding. Consequently, both the IPCC fifth assessment report and the ESA-GEWEX report 'Earth Observation and Water Cycle Science Priorities' have identified an urgent need for long-term observations and improved process understanding in the UTLS region. To close this gap, the authors propose the 'WAter Vapour European - Explorer' (WAVE-E) space mission, whose primary goal is to monitor water vapor in the UTLS at 1 km vertical, 25 km horizontal and sub-daily temporal resolution. WAVE-E consists of three quasi-identical small ( 500 kg) satellites (WAVE-E 1-3) in a constellation of Sun-Synchronous Low Earth Orbits, each carrying a limb sounding and cross-track scanning mid-infrared passive spectrometer (824 cm-1 to 829 cm-1). The core of the instruments builds a monolithic, field-widened type of Michelson interferometer without any moving parts, rendering it rigid and fault tolerant. Synergistic use of WAVE-E and MetOp-NG operational satellites is identified, such that a data fusion algorithm could provide water vapour profiles from the

Magnetohydrodynamic waves, electrohydrodynamic waves and photons

International Nuclear Information System (INIS)

Carstoin, J.

1984-01-01

Two new subjects have lately attracted increased attention: the magnetohydrodynamics (m.h.d.) and the theory of lasers. Equally important is the subject of electrohydrodynamics (e.h.d.). Now, clearly, all electromagnetic waves carry photons; it is the merit of Louis de Broglie to have had reconciled the validity of the Maxwell equations with existence of the latter. I have, recently, derived L. de Broglie's equations from the equations C. It seems natural to assume that the m.h.d. waves carry also photons, but how to reconcile the m.h.d axioms with the existence of photons ... a problem which has, so far, escaped the notice of physicists. In the lines which follows, an attempt is made to incorporate the photons in the m.h.d. waves, re e.h.d. waves in a rather simple fashion

Design wave estimation considering directional distribution of waves

Digital Repository Service at National Institute of Oceanography (India)

SanilKumar, V.; Deo, M.C

.elsevier.com/locate/oceaneng Technical Note Design wave estimation considering directional distribution of waves V. Sanil Kumar a,C3 , M.C. Deo b a OceanEngineeringDivision,NationalInstituteofOceanography,Donapaula,Goa-403004,India b Civil... of Physical Oceanography Norway, Report method for the routine 18, 1020–1034. ocean waves. Division of No. UR-80-09, 187 p. analysis of pitch and roll Conference on Coastal Engineering, 1. ASCE, Taiwan, pp. 136–149. Deo, M.C., Burrows, R., 1986. Extreme wave...

Coherent Wave Measurement Buoy Arrays to Support Wave Energy Extraction

Science.gov (United States)

Spada, F.; Chang, G.; Jones, C.; Janssen, T. T.; Barney, P.; Roberts, J.

2016-02-01

Wave energy is the most abundant form of hydrokinetic energy in the United States and wave energy converters (WECs) are being developed to extract the maximum possible power from the prevailing wave climate. However, maximum wave energy capture is currently limited by the narrow banded frequency response of WECs as well as extended protective shutdown requirements during periods of large waves. These limitations must be overcome in order to maximize energy extraction, thus significantly decreasing the cost of wave energy and making it a viable energy source. Techno-economic studies of several WEC devices have shown significant potential to improve wave energy capture efficiency through operational control strategies that incorporate real-time information about local surface wave motions. Integral Consulting Inc., with ARPA-E support, is partnering with Sandia National Laboratories and Spoondrift LLC to develop a coherent array of wave-measuring devices to relay and enable the prediction of wave-resolved surface dynamics at a WEC location ahead of real time. This capability will provide necessary information to optimize power production of WECs through control strategies, thereby allowing for a single WEC design to perform more effectively across a wide range of wave environments. The information, data, or work presented herein was funded in part by the Advanced Research Projects Agency-Energy (ARPA-E), U.S. Department of Energy, under Award Number DE-AR0000514.

How to turn gravity waves into Alfven waves and other such tricks

International Nuclear Information System (INIS)

Newington, Marie E; Cally, Paul S

2011-01-01

Recent observations of travelling gravity waves at the base of the chromosphere suggest an interplay between gravity wave propagation and magnetic field. Our aims are: to explain the observation that gravity wave flux is suppressed in magnetic regions; to understand why we see travelling waves instead of standing waves; and to see if gravity waves can undergo mode conversion and couple to Alfven waves in regions where the plasma beta is of order unity. We model gravity waves in a VAL C atmosphere, subject to a uniform magnetic field of various orientations, considering both adiabatic and radiatively damped propagation. Results indicate that in the presence of a magnetic field, the gravity wave can propagate as a travelling wave, with the magnetic field orientation playing a crucial role in determining the wave character. For the majority of magnetic field orientations, the gravity wave is reflected at low heights as a slow magneto-acoustic wave, explaining the observation of reduced flux in magnetic regions. In a highly inclined magnetic field, the gravity wave undergoes mode conversion to either field guided acoustic waves or Alfven waves. The primary effect of incorporating radiative damping is a reduction in acoustic and magnetic fluxes measured at the top of the integration region. By demonstrating the mode conversion of gravity waves to Alfven waves, this work identifies a possible pathway for energy transport from the solar surface to the upper atmosphere.

Chlamydia trachomatis co-opts GBF1 and CERT to acquire host sphingomyelin for distinct roles during intracellular development.

Directory of Open Access Journals (Sweden)

Cherilyn A Elwell

2011-09-01

Full Text Available The strain designated Chlamydia trachomatis serovar that was used for experiments in this paper is Chlamydia muridarum, a species closely related to C. trachomatis (and formerly termed the Mouse Pneumonitis strain of C. trachomatis. [corrected]. The obligate intracellular pathogen Chlamydia trachomatis replicates within a membrane-bound inclusion that acquires host sphingomyelin (SM, a process that is essential for replication as well as inclusion biogenesis. Previous studies demonstrate that SM is acquired by a Brefeldin A (BFA-sensitive vesicular trafficking pathway, although paradoxically, this pathway is dispensable for bacterial replication. This finding suggests that other lipid transport mechanisms are involved in the acquisition of host SM. In this work, we interrogated the role of specific components of BFA-sensitive and BFA-insensitive lipid trafficking pathways to define their contribution in SM acquisition during infection. We found that C. trachomatis hijacks components of both vesicular and non-vesicular lipid trafficking pathways for SM acquisition but that the SM obtained from these separate pathways is being utilized by the pathogen in different ways. We show that C. trachomatis selectively co-opts only one of the three known BFA targets, GBF1, a regulator of Arf1-dependent vesicular trafficking within the early secretory pathway for vesicle-mediated SM acquisition. The Arf1/GBF1-dependent pathway of SM acquisition is essential for inclusion membrane growth and stability but is not required for bacterial replication. In contrast, we show that C. trachomatis co-opts CERT, a lipid transfer protein that is a key component in non-vesicular ER to trans-Golgi trafficking of ceramide (the precursor for SM, for C. trachomatis replication. We demonstrate that C. trachomatis recruits CERT, its ER binding partner, VAP-A, and SM synthases, SMS1 and SMS2, to the inclusion and propose that these proteins establish an on-site SM biosynthetic

Abnormal Waves Modelled as Second-order Conditional Waves

DEFF Research Database (Denmark)

Jensen, Jørgen Juncher

2005-01-01

The paper presents results for the expected second order short-crested wave conditional of a given wave crest at a specific point in time and space. The analysis is based on the second order Sharma and Dean shallow water wave theory. Numerical results showing the importance of the spectral densit...

Wave-induced current considering wave-tide interaction in Haeundae

Science.gov (United States)

Lim, Hak Soo

2017-04-01

The Haeundae, located at the south eastern end of the Korean Peninsula, is a famous beach, which has an approximately 1.6 km long and 70 m wide coastline. The beach has been repeatedly eroded by the swell waves caused by typhoons in summer and high waves originating in the East Sea in winter. The Korean government conducted beach restoration projects including beach nourishment (620,000 m3) and construction of two submerged breakwaters near both ends of the beach. To prevent the beach erosion and to support the beach restoration project, the Korean government initiated a R&D project, the development of coastal erosion control technology since 2013. As a part of the project, we have been measuring waves and currents at a water depth of 22 m, 1.8 km away from the beach using an acoustic wave and current meter (AWAC) continuously for more than three years; we have also measured waves and currents intensively near the surf-zone in summer and winter. In this study, a numerical simulation using a wave and current coupled model (ROMS-SWAN) was conducted for determining the wave-induced current considering seasonal swell waves (Hs : 2.5 m, Tp: 12 s) and for better understanding of the coastal process near the surf-zone in Haeundae. By comparing the measured and simulated results, we found that cross-shore current during summer is mainly caused by the eddy produced by the wave-induced current near the beach, which in turn, is generated by the strong waves coming from the SSW and S directions. During other seasons, longshore wave-induced current is produced by the swell waves coming from the E and ESE directions. The longshore current heading west toward Dong-Back Island, west end of the beach, during all the seasons and eddy current toward Mipo-Port, east end of the beach, in summer which is well matched with the observed residual current. The wave-induced current with long-term measurement data is incorporated in simulation of sediment transport modeling for developing

Impacts of wave energy conversion devices on local wave climate: observations and modelling from the Perth Wave Energy Project

Science.gov (United States)

Hoeke, Ron; Hemer, Mark; Contardo, Stephanie; Symonds, Graham; Mcinnes, Kathy

2016-04-01

As demonstrated by the Australian Wave Energy Atlas (AWavEA), the southern and western margins of the country possess considerable wave energy resources. The Australia Government has made notable investments in pre-commercial wave energy developments in these areas, however little is known about how this technology may impact local wave climate and subsequently affect neighbouring coastal environments, e.g. altering sediment transport, causing shoreline erosion or accretion. In this study, a network of in-situ wave measurement devices have been deployed surrounding the 3 wave energy converters of the Carnegie Wave Energy Limited's Perth Wave Energy Project. This data is being used to develop, calibrate and validate numerical simulations of the project site. Early stage results will be presented and potential simulation strategies for scaling-up the findings to larger arrays of wave energy converters will be discussed. The intended project outcomes are to establish zones of impact defined in terms of changes in local wave energy spectra and to initiate best practice guidelines for the establishment of wave energy conversion sites.

Testing, Analysis and Control of Wave Dragon, Wave Energy Converter

DEFF Research Database (Denmark)

Tedd, James

of the incident waves upon a wave device allows the possibility of accurately tuning the power-take off mechanism (the hydro-turbines for the Wave Dragon) to capture more energy. A digital filter method for performing this prediction in real-time with minimal computational effort is presented. Construction...... of digital filters is well known within signal processing, but their use for this application in Wave Energy is new. The filter must be designed carefully as the frequency components of waves travel at different speeds. Research presented in this thesis has advanced the development of the Wave Dragon device...

Alfvén wave mixing and non-JWKB waves in stellar winds

International Nuclear Information System (INIS)

Webb, G M; McKenzie, J F; Hu, Q; Zank, G P

2013-01-01

Alfvén wave mixing equations used in locally incompressible turbulence transport equations in the solar wind contain as a special case, non-Jeffreys–Wentzel–Kramers–Brouillon (non-JWKB) wave equations used in models of Alfvén wave driven winds. We discuss the canonical wave energy equation; the physical wave energy equation, and the JWKB limit of the wave interaction equations. Lagrangian and Hamiltonian variational principles for the waves are developed. Noether’s theorem is used to derive the canonical wave energy equation which is associated with the linearity symmetry of the equations. A further conservation law associated with time translation invariance of the action, applicable for steady background wind flows is also derived. In the latter case, the conserved density is the Hamiltonian density for the waves, which is distinct from the canonical wave energy density. The canonical wave energy conservation law is a special case of a wider class of conservation laws associated with Green’s theorem for the wave mixing system and the adjoint wave mixing system, which are related to Noether’s second theorem. In the sub-Alfvénic flow, inside the Alfvén point of the wind, the backward and forward waves have positive canonical energy densities, but in the super-Alfvénic flow outside the Alfvén critical point, the backward Alfvén waves are negative canonical energy waves, and the forward Alfvén waves are positive canonical energy waves. Reflection and transmission coefficients for the backward and forward waves in both the sub-Alfvénic and super-Alfvénic regions of the flow are discussed. (paper)

Perineal injuries and birth positions among 2992 women with a low risk pregnancy who opted for a homebirth

DEFF Research Database (Denmark)

Edqvist, Malin; Blix, Ellen; Hegaard, Hanne K

2016-01-01

at home and to compare the prevalence of perineal injuries, SPT and episiotomy in different birth positions in four Nordic countries. METHODS: A population-based prospective cohort study of planned home births in four Nordic countries. To assess medical outcomes a questionnaire completed after birth...... by the attending midwife was used. Descriptive statistics, bivariate analysis and logistic regression were used to analyze the data. RESULTS: Two thousand nine hundred ninety-two women with planned home births, who birthed spontaneously at home or after transfer to hospital, between 2008 and 2013 were included.......26-1.79). Flexible sacrum positions were associated with fewer episiotomies (OR 0.20; CI 95 % 0.10-0.54). CONCLUSION: A low prevalence of SPT and episiotomy was found among women opting for a home birth in four Nordic countries. Women used a variety of birth positions and a majority gave birth in flexible sacrum...

Statistical Analysis of Wave Climate Data Using Mixed Distributions and Extreme Wave Prediction

Directory of Open Access Journals (Sweden)

Wei Li

2016-05-01

Full Text Available The investigation of various aspects of the wave climate at a wave energy test site is essential for the development of reliable and efficient wave energy conversion technology. This paper presents studies of the wave climate based on nine years of wave observations from the 2005–2013 period measured with a wave measurement buoy at the Lysekil wave energy test site located off the west coast of Sweden. A detailed analysis of the wave statistics is investigated to reveal the characteristics of the wave climate at this specific test site. The long-term extreme waves are estimated from applying the Peak over Threshold (POT method on the measured wave data. The significant wave height and the maximum wave height at the test site for different return periods are also compared. In this study, a new approach using a mixed-distribution model is proposed to describe the long-term behavior of the significant wave height and it shows an impressive goodness of fit to wave data from the test site. The mixed-distribution model is also applied to measured wave data from four other sites and it provides an illustration of the general applicability of the proposed model. The methodologies used in this paper can be applied to general wave climate analysis of wave energy test sites to estimate extreme waves for the survivability assessment of wave energy converters and characterize the long wave climate to forecast the wave energy resource of the test sites and the energy production of the wave energy converters.

Waves in the seas

Digital Repository Service at National Institute of Oceanography (India)

Varkey, M.J

, steep nonsymmetric cnoidal waves, solitons and random waves. They have different properties too. Any wave form has a wave period (T), wave height (H) and speed (C) which depends on T. Still another type of waves are breaking waves near a coast...

Millimeter wave scattering off a whistler wave in a tokamak

International Nuclear Information System (INIS)

Sawhney, B.K.; Singh, S.V.; Tripathi, V.K.

1994-01-01

Obliquely propagating whistler waves through a plasma cause density perturbations. A high frequency electromagnetic wave sent into such a perturbed region suffers scattering. The process can be used as a diagnostics for whistler. We have developed a theory of electromagnetic wave scattering in a tokamak where density profile is taken a parabolic. Numerical calculations have been carried out to evaluate the ratio of the power of the scattered electromagnetic wave to that of the incident electromagnetic wave. The scattered power decreases with the frequency of the incident electromagnetic wave. For typical parameters, the ratio of the power of the scattered to the incident electromagnetic wave comes out to be of the order of 10 -4 at a scattering angle of 3 which can be detected. (author). 2 refs, 1 fig

The effect of lower-hybrid waves on the propagation of hydromagnetic waves

International Nuclear Information System (INIS)

Hamabata, Hiromitsu; Namikawa, Tomikazu; Mori, Kazuhiro

1988-01-01

Propagation characteristics of hydromagnetic waves in a magnetic plasma are investigated using the two-plasma fluid equations including the effect of lower-hybrid waves propagating perpendicularly to the magnetic field. The effect of lower-hybrid waves on the propagation of hydromagnetic waves is analysed in terms of phase speed, growth rate, refractive index, polarization and the amplitude relation between the density perturbation and the magnetic-field perturbation for the cases when hydromagnetic waves propagate in the plane whose normal is perpendicular to both the magnetic field and the propagation direction of lower-hybrid waves and in the plane perpendicular to the propagation direction of lower-hybrid waves. It is shown that hydromagnetic waves propagating at small angles to the propagation direction of lower-hybrid waves can be excited by the effect of lower-hybrid waves and the energy of excited waves propagates nearly parallel to the propagation direction of lower-hybrid waves. (author)

COMPARISON STUDY OF EXPERIMENTS AND PREDICTIONS OF WAVE KINEMATICS FOR ROGUE WAVE

Directory of Open Access Journals (Sweden)

Hae Jin Choi

2018-01-01

Full Text Available To investigate the wave kinematics under the rogue wave crest, a series of experiments were performed in 2-D wave tank with the application of PIV technique to measure the velocities under the free surface. Three different prediction methods of linear extrapolation, Wheeler stretching, and modified stretching were applied to estimate water wave kinematics and compared with PIV experimental results under the highest wave crest of irregular wave trains satisfying with rogue wave criteria. Also, the cut-off frequency dependence for three prediction methods was investigated with varying spectral peak frequencies to estimate wave kinematics including velocities and accelerations in horizontal and vertical directions. It was suggested that the cut-off frequency for the reasonable prediction of the wave kinematics under the rogue wave crest could be chosen three times of spectral peak wave frequency for the linear extrapolation and higher frequency than four times of spectral peak wave frequency for Wheeler stretching and modified stretching method.

Bursts of electron waves modulated by oblique ion waves

International Nuclear Information System (INIS)

Boswell, R.W.

1984-01-01

Experimental evidence is presented which shows small packets of electron plasma waves modulated by large amplitude obliquely propagating non-linear ion plasma waves. Very often the whole system is modulated by an oscillation near the ion gyro frequency or its harmonics. The ion waves seem to be similar to those measured in the current carrying auroral plasma. These results suggest that the generation of ion and electron waves in the auroral plasma may be correlated

Assessing wave energy effects on biodiversity: the wave hub experience.

Science.gov (United States)

Witt, M J; Sheehan, E V; Bearhop, S; Broderick, A C; Conley, D C; Cotterell, S P; Crow, E; Grecian, W J; Halsband, C; Hodgson, D J; Hosegood, P; Inger, R; Miller, P I; Sims, D W; Thompson, R C; Vanstaen, K; Votier, S C; Attrill, M J; Godley, B J

2012-01-28

Marine renewable energy installations harnessing energy from wind, wave and tidal resources are likely to become a large part of the future energy mix worldwide. The potential to gather energy from waves has recently seen increasing interest, with pilot developments in several nations. Although technology to harness wave energy lags behind that of wind and tidal generation, it has the potential to contribute significantly to energy production. As wave energy technology matures and becomes more widespread, it is likely to result in further transformation of our coastal seas. Such changes are accompanied by uncertainty regarding their impacts on biodiversity. To date, impacts have not been assessed, as wave energy converters have yet to be fully developed. Therefore, there is a pressing need to build a framework of understanding regarding the potential impacts of these technologies, underpinned by methodologies that are transferable and scalable across sites to facilitate formal meta-analysis. We first review the potential positive and negative effects of wave energy generation, and then, with specific reference to our work at the Wave Hub (a wave energy test site in southwest England, UK), we set out the methodological approaches needed to assess possible effects of wave energy on biodiversity. We highlight the need for national and international research clusters to accelerate the implementation of wave energy, within a coherent understanding of potential effects-both positive and negative.

Fast wave current drive above the slow wave density limit

International Nuclear Information System (INIS)

McWilliams, R.; Sheehan, D.P.; Wolf, N.S.; Edrich, D.

1989-01-01

Fast wave and slow wave current drive near the mean gyrofrequency were compared in the Irvine Torus using distinct phased array antennae of similar principal wavelengths, frequencies, and input powers. The slow wave current drive density limit was measured for 50ω ci ≤ω≤500ω ci and found to agree with trends in tokamaks. Fast wave current drive was observed at densities up to the operating limit of the torus, demonstrably above the slow wave density limit

Nonlinear Waves on Stochastic Support: Calcium Waves in Astrocyte Syncytia

Science.gov (United States)

Jung, P.; Cornell-Bell, A. H.

Astrocyte-signaling has been observed in cell cultures and brain slices in the form of Calcium waves. Their functional relevance for neuronal communication, brain functions and diseases is, however, not understood. In this paper, the propagation of intercellular calcium waves is modeled in terms of waves in excitable media on a stochastic support. We utilize a novel method to decompose the spatiotemporal patterns into space-time clusters (wave fragments). Based on this cluster decomposition, a statistical description of wave patterns is developed.

Detonation Wave Profile

Energy Technology Data Exchange (ETDEWEB)

Menikoff, Ralph [Los Alamos National Laboratory

2015-12-14

The Zel’dovich-von Neumann-Doering (ZND) profile of a detonation wave is derived. Two basic assumptions are required: i. An equation of state (EOS) for a partly burned explosive; P(V, e, λ). ii. A burn rate for the reaction progress variable; d/dt λ = R(V, e, λ). For a steady planar detonation wave the reactive flow PDEs can be reduced to ODEs. The detonation wave profile can be determined from an ODE plus algebraic equations for points on the partly burned detonation loci with a specified wave speed. Furthermore, for the CJ detonation speed the end of the reaction zone is sonic. A solution to the reactive flow equations can be constructed with a rarefaction wave following the detonation wave profile. This corresponds to an underdriven detonation wave, and the rarefaction is know as a Taylor wave.

A wave model test bed study for wave energy resource characterization

Energy Technology Data Exchange (ETDEWEB)

Yang, Zhaoqing; Neary, Vincent S.; Wang, Taiping; Gunawan, Budi; Dallman, Annie R.; Wu, Wei-Cheng

2017-12-01

This paper presents a test bed study conducted to evaluate best practices in wave modeling to characterize energy resources. The model test bed off the central Oregon Coast was selected because of the high wave energy and available measured data at the site. Two third-generation spectral wave models, SWAN and WWIII, were evaluated. A four-level nested-grid approach—from global to test bed scale—was employed. Model skills were assessed using a set of model performance metrics based on comparing six simulated wave resource parameters to observations from a wave buoy inside the test bed. Both WWIII and SWAN performed well at the test bed site and exhibited similar modeling skills. The ST4 package with WWIII, which represents better physics for wave growth and dissipation, out-performed ST2 physics and improved wave power density and significant wave height predictions. However, ST4 physics tended to overpredict the wave energy period. The newly developed ST6 physics did not improve the overall model skill for predicting the six wave resource parameters. Sensitivity analysis using different wave frequencies and direction resolutions indicated the model results were not sensitive to spectral resolutions at the test bed site, likely due to the absence of complex bathymetric and geometric features.

Spike-like solitary waves in incompressible boundary layers driven by a travelling wave.

Science.gov (United States)

Feng, Peihua; Zhang, Jiazhong; Wang, Wei

2016-06-01

Nonlinear waves produced in an incompressible boundary layer driven by a travelling wave are investigated, with damping considered as well. As one of the typical nonlinear waves, the spike-like wave is governed by the driven-damped Benjamin-Ono equation. The wave field enters a completely irregular state beyond a critical time, increasing the amplitude of the driving wave continuously. On the other hand, the number of spikes of solitary waves increases through multiplication of the wave pattern. The wave energy grows in a sequence of sharp steps, and hysteresis loops are found in the system. The wave energy jumps to different levels with multiplication of the wave, which is described by winding number bifurcation of phase trajectories. Also, the phenomenon of multiplication and hysteresis steps is found when varying the speed of driving wave as well. Moreover, the nature of the change of wave pattern and its energy is the stability loss of the wave caused by saddle-node bifurcation.

Wave-current interactions at the FloWave Ocean Energy Research Facility

Science.gov (United States)

Noble, Donald; Davey, Thomas; Steynor, Jeffrey; Bruce, Tom; Smith, Helen; Kaklis, Panagiotis

2015-04-01

Physical scale model testing is an important part of the marine renewable energy development process, allowing the study of forces and device behaviour in a controlled environment prior to deployment at sea. FloWave is a new state-of-the-art ocean energy research facility, designed to provide large scale physical modelling services to the tidal and wave sector. It has the unique ability to provide complex multi-directional waves that can be combined with currents from any direction in the 25m diameter circular tank. The facility is optimised for waves around 2s period and 0.4m height, and is capable of generating currents upwards of 1.6m/s. This offers the ability to model metocean conditions suitable for most renewable energy devices at a typical scale of between 1:10 and 1:40. The test section is 2m deep, which can be classed as intermediate-depth for most waves of interest, thus the full dispersion equation must be solved as the asymptotic simplifications do not apply. The interaction between waves and currents has been studied in the tank. This has involved producing in the tank sets of regular waves, focussed wave groups, and random sea spectra including multi-directional sea states. These waves have been both inline-with and opposing the current, as well as investigating waves at arbitrary angles to the current. Changes in wave height and wavelength have been measured, and compared with theoretical results. Using theoretical wave-current interaction models, methods have been explored to "correct" the wave height in the central test area of the tank when combined with a steady current. This allows the wave height with current to be set equal to that without a current. Thus permitting, for example, direct comparison of device motion response between tests with and without current. Alternatively, this would also permit a specific wave height and current combination to be produced in the tank, reproducing recorded conditions at a particular site of interest. The

THE EFFECTS OF WAVE ESCAPE ON FAST MAGNETOSONIC WAVE TURBULENCE IN SOLAR FLARES

International Nuclear Information System (INIS)

Pongkitiwanichakul, Peera; Chandran, Benjamin D. G.; Karpen, Judith T.; DeVore, C. Richard

2012-01-01

One of the leading models for electron acceleration in solar flares is stochastic acceleration by weakly turbulent fast magnetosonic waves ( f ast waves ) . In this model, large-scale flows triggered by magnetic reconnection excite large-wavelength fast waves, and fast-wave energy then cascades from large wavelengths to small wavelengths. Electron acceleration by large-wavelength fast waves is weak, and so the model relies on the small-wavelength waves produced by the turbulent cascade. In order for the model to work, the energy cascade time for large-wavelength fast waves must be shorter than the time required for the waves to propagate out of the solar-flare acceleration region. To investigate the effects of wave escape, we solve the wave kinetic equation for fast waves in weak turbulence theory, supplemented with a homogeneous wave-loss term. We find that the amplitude of large-wavelength fast waves must exceed a minimum threshold in order for a significant fraction of the wave energy to cascade to small wavelengths before the waves leave the acceleration region. We evaluate this threshold as a function of the dominant wavelength of the fast waves that are initially excited by reconnection outflows.

Directional nonlinear guided wave mixing: Case study of counter-propagating shear horizontal waves

Science.gov (United States)

Hasanian, Mostafa; Lissenden, Cliff J.

2018-04-01

While much nonlinear ultrasonics research has been conducted on higher harmonic generation, wave mixing provides the potential for sensitive measurements of incipient damage unencumbered by instrumentation nonlinearity. Studies of nonlinear ultrasonic wave mixing, both collinear and noncollinear, for bulk waves have shown the robust capability of wave mixing for early damage detection. One merit of bulk wave mixing lies in their non-dispersive nature, but guided waves enable inspection of otherwise inaccessible material and a variety of mixing options. Co-directional guided wave mixing was studied previously, but arbitrary direction guided wave mixing has not been addressed until recently. Wave vector analysis is applied to study variable mixing angles to find wave mode triplets (two primary waves and a secondary wave) resulting in the phase matching condition. As a case study, counter-propagating Shear Horizontal (SH) guided wave mixing is analyzed. SH wave interactions generate a secondary Lamb wave mode that is readily receivable. Reception of the secondary Lamb wave mode is compared for an angle beam transducer, an air coupled transducer, and a laser Doppler vibrometer (LDV). Results from the angle beam and air coupled transducers are quite consistent, while the LDV measurement is plagued by variability issues.

Reduced-order prediction of rogue waves in two-dimensional deep-water waves

Science.gov (United States)

Sapsis, Themistoklis; Farazmand, Mohammad

2017-11-01

We consider the problem of large wave prediction in two-dimensional water waves. Such waves form due to the synergistic effect of dispersive mixing of smaller wave groups and the action of localized nonlinear wave interactions that leads to focusing. Instead of a direct simulation approach, we rely on the decomposition of the wave field into a discrete set of localized wave groups with optimal length scales and amplitudes. Due to the short-term character of the prediction, these wave groups do not interact and therefore their dynamics can be characterized individually. Using direct numerical simulations of the governing envelope equations we precompute the expected maximum elevation for each of those wave groups. The combination of the wave field decomposition algorithm, which provides information about the statistics of the system, and the precomputed map for the expected wave group elevation, which encodes dynamical information, allows (i) for understanding of how the probability of occurrence of rogue waves changes as the spectrum parameters vary, (ii) the computation of a critical length scale characterizing wave groups with high probability of evolving to rogue waves, and (iii) the formulation of a robust and parsimonious reduced-order prediction scheme for large waves. T.S. has been supported through the ONR Grants N00014-14-1-0520 and N00014-15-1-2381 and the AFOSR Grant FA9550-16-1-0231. M.F. has been supported through the second Grant.

Wave Dragon

DEFF Research Database (Denmark)

Kofoed, Jens Peter; Frigaard, Peter; Sørensen, H. C.

1998-01-01

This paper concerns with the development of the wave energy converter (WEC) Wave Dragon. This WEC is based on the overtopping principle. An overview of the performed research done concerning the Wave Dragon over the past years is given, and the results of one of the more comprehensive studies, co...

Revisiting the difference between traveling-wave and standing-wave thermoacoustic engines - A simple analytical model for the standing-wave one

Science.gov (United States)

Yasui, Kyuichi; Kozuka, Teruyuki; Yasuoka, Masaki; Kato, Kazumi

2015-11-01

There are two major categories in a thermoacoustic prime-mover. One is the traveling-wave type and the other is the standing-wave type. A simple analytical model of a standing-wave thermoacoustic prime-mover is proposed at relatively low heat-flux for a stack much shorter than the acoustic wavelength, which approximately describes the Brayton cycle. Numerical simulations of Rott's equations have revealed that the work flow (acoustic power) increases by increasing of the amplitude of the particle velocity (| U|) for the traveling-wave type and by increasing cosΦ for the standing-wave type, where Φ is the phase difference between the particle velocity and the acoustic pressure. In other words, the standing-wave type is a phase-dominant type while the traveling-wave type is an amplitude-dominant one. The ratio of the absolute value of the traveling-wave component (| U|cosΦ) to that of the standing-wave component (| U|sinΦ) of any thermoacoustic engine roughly equals the ratio of the absolute value of the increasing rate of | U| to that of cosΦ. The different mechanism between the traveling-wave and the standing-wave type is discussed regarding the dependence of the energy efficiency on the acoustic impedance of a stack as well as that on ωτα, where ω is the angular frequency of an acoustic wave and τα is the thermal relaxation time. While the energy efficiency of the traveling-wave type at the optimal ωτα is much higher than that of the standing-wave type, the energy efficiency of the standing-wave type is higher than that of the traveling-wave type at much higher ωτα under a fixed temperature difference between the cold and the hot ends of the stack.

Simulation of Wave Overtopping of Maritime Structures in a Numerical Wave Flume

Directory of Open Access Journals (Sweden)

Tiago C. A. Oliveira

2012-01-01

Full Text Available A numerical wave flume based on the particle finite element method (PFEM is applied to simulate wave overtopping for impermeable maritime structures. An assessment of the performance and robustness of the numerical wave flume is carried out for two different cases comparing numerical results with experimental data. In the first case, a well-defined benchmark test of a simple low-crested structure overtopped by regular nonbreaking waves is presented, tested in the lab, and simulated in the numerical wave flume. In the second case, state-of-the-art physical experiments of a trapezoidal structure placed on a sloping beach overtopped by regular breaking waves are simulated in the numerical wave flume. For both cases, main overtopping events are well detected by the numerical wave flume. However, nonlinear processes controlling the tests proposed, such as nonlinear wave generation, energy losses along the wave propagation track, wave reflection, and overtopping events, are reproduced with more accuracy in the first case. Results indicate that a numerical wave flume based on the PFEM can be applied as an efficient tool to supplement physical models, semiempirical formulations, and other numerical techniques to deal with overtopping of maritime structures.

Waves in plasmas (part 1 - wave-plasma interaction general background)

International Nuclear Information System (INIS)

Dumont, R.

2004-01-01

This document gathers a series of transparencies presented in the framework of the week-long lectures 'hot plasmas 2004' and dedicated to the physics of wave-plasma interaction. The structure of this document is as follows: 1) wave and diverse plasmas, 2) basic equations (Maxwell equations), 3) waves in a fluid plasma, and 4) waves in a kinetic plasma (collisionless plasma)

Alternative methods for ray tracing in uniaxial media. Application to negative refraction

Science.gov (United States)

Bellver-Cebreros, Consuelo; Rodriguez-Danta, Marcelo

2007-03-01

In previous papers [C. Bellver-Cebreros, M. Rodriguez-Danta, Eikonal equation, alternative expression of Fresnel's equation and Mohr's construction in optical anisotropic media, Opt. Commun. 189 (2001) 193; C. Bellver-Cebreros, M. Rodriguez-Danta, Internal conical refraction in biaxial media and graphical plane constructions deduced from Mohr's method, Opt. Commun. 212 (2002) 199; C. Bellver-Cebreros, M. Rodriguez-Danta, Refraccion conica externa en medios biaxicos a partir de la construccion de Mohr, Opt. Pura AppliE 36 (2003) 33], the authors have developed a method based on the local properties of dielectric permittivity tensor and on Mohr's plane graphical construction in order to study the behaviour of locally plane light waves in anisotropic media. In this paper, this alternative methodology is compared with the traditional one, by emphasizing the simplicity of the former when studying ray propagation through uniaxial media (comparison is possible since, in this case, traditional construction becomes also plane). An original and simple graphical method is proposed in order to determine the direction of propagation given by the wave vector from the knowledge of the extraordinary ray direction (given by Poynting vector). Some properties of light rays in these media not described in the literature are obtained. Finally, two applications are considered: a description of optical birefringence under normal incidence and the study of negative refraction in uniaxial media.

Wave kinematics and response of slender offshore structures. Vol 4: Wave kinematics

Energy Technology Data Exchange (ETDEWEB)

Riber, H.J.

1999-08-01

The kinematics of large surface waves has been measured by means of sonar's placed on the sea floor at the Tyra field. Measurements from the most severe storm are analysed and extreme wave velocity profiles are compared to Stoke wave velocity profiles. Statistical distributions of crest velocity and wave celerity are presented. The analysis shows how the deviation from the Stokes prediction varies with wave heights and steepness. Analyses of the directional wave field leads to the conclusion that the extreme waves are three-dimensional. It is shown that the peculiar kinematics of extreme waves is of great relevance to the design of jacket type structures. (au)

Evolution of optical vortex distributions in stochastic vortex fields

CSIR Research Space (South Africa)

Roux, FS

2011-01-01

Full Text Available simple decay process to restore equilibrium. More complicated dynamics are involved, which requires deeper investigations. REFERENCES [1] Nye, J. F. and Berry, M. V., ?Dislocations in wave trains,? Proc. R. Soc. Lond. A 336, 165?190 (1974). [2] Dennis..., J., Zambrini, R., Dennis, M., and Vasnetsov, M., ?Angular momentum of optical vortex arrays,? Opt. Express 14, 938?949 (2006). [27] Berry, M. V., ?Disruption of wavefronts: statistics of dislocations in incoherent gaussian random waves,? J. Phys...

Observations of Convectively Coupled Kelvin Waves forced by Extratropical Wave Activity

Science.gov (United States)

Kiladis, G. N.; Biello, J. A.; Straub, K. H.

2012-12-01

It is well established by observations that deep tropical convection can in certain situations be forced by extratropical Rossby wave activity. Such interactions are a well-known feature of regions of upper level westerly flow, and in particular where westerlies and equatorward wave guiding by the basic state occur at low enough latitudes to interact with tropical and subtropical moisture sources. In these regions convection is commonly initiated ahead of upper level troughs, characteristic of forcing by quasi-geostrophic dynamics. However, recent observational evidence indicates that extratropical wave activity is also associated with equatorial convection even in regions where there is a "critical line" to Rossby wave propagation at upper levels, that is, where the zonal phase speed of the wave is equal to the zonal flow speed. A common manifestation of this type of interaction involves the initiation of convectively coupled Kelvin waves, as well as mixed Rossby-gravity (MRG) waves. These waves are responsible for a large portion of the convective variability within the ITCZ over the Indian, Pacific, and Atlantic sectors, as well as within the Amazon Basin of South America. For example, Kelvin waves originating within the western Pacific ITCZ are often triggered by Rossby wave activity propagating into the Australasian region from the South Indian Ocean extratropics. At other times, Kelvin waves are seen to originate along the eastern slope of the Andes. In the latter case the initial forcing is sometimes linked to a low-level "pressure surge," initiated by wave activity propagating equatorward from the South Pacific storm track. In yet other cases, such as over Africa, the forcing appears to be related to wave activity in the extratropics which is not necessarily propagating into low latitudes, but appears to "project" onto the Kelvin structure, in line with past theoretical and modeling studies. Observational evidence for extratropical forcing of Kelvin and MRG

Wave phenomena

CERN Document Server

Towne, Dudley H

1988-01-01

This excellent undergraduate-level text emphasizes optics and acoustics, covering inductive derivation of the equation for transverse waves on a string, acoustic plane waves, boundary-value problems, polarization, three-dimensional waves and more. With numerous problems (solutions for about half). ""The material is superbly chosen and brilliantly written"" - Physics Today. Problems. Appendices.

Soliton wave-speed management: Slowing, stopping, or reversing a solitary wave

Science.gov (United States)

Baines, Luke W. S.; Van Gorder, Robert A.

2018-06-01

While dispersion management is a well-known tool to control soliton properties such as shape or amplitude, far less effort has been directed toward the theoretical control of the soliton wave speed. However, recent experiments concerning the stopping or slowing of light demonstrate that the control of the soliton wave speed is of experimental interest. Motivated by these and other studies, we propose a management approach for modifying the wave speed of a soliton (or of other nonlinear wave solutions, such as periodic cnoidal waves) under the nonlinear Schrödinger equation. Making use of this approach, we are able to slow, stop, or even reverse a solitary wave, and we give several examples to bright solitons, dark solitons, and periodic wave trains, to demonstrate the method. An extension of the approach to spatially heterogeneous media, for which the wave may propagate differently at different spatial locations, is also discussed.

Accuracy of visual wave observation from merchant ships and estimated wave loads; Accuracy of visual wave observation from merchant ships and estimated wave loads

Energy Technology Data Exchange (ETDEWEB)

Kawabe, H. [National Defense Academy, Kanagawa (Japan); Masaoka, K. [University of Osaka Prefecture, Osaka (Japan). Faculty of Engineering

1998-06-01

There is a large number of studies on discussions concerning accuracy of visual observation of waves and the correction method thereon. This paper give considerations on observation accuracy placing a viewpoint on that by merchant ships. Based on ship meteorological observation tables reported to the Meteorological Agency of Japan on meteorology in North Pacific during 14 years from 1976 to1989, wave observation values taken by merchant ships and observation ships were compared statistically to investigate the accuracy of visual wave observations carried out by merchant ships. With regard to wave heights, the observation values taken by the observation ships and the merchant ships have strong correlation, where the merchant ships evaluate them somewhat higher than the observation ships. Regarding wave cycles of wind waves, the merchant ships tend to have the observation values on longer cycle side. Correlation between the observations values by the merchant ships and the observation ships is weak both in wind waves and swells. There is not much of variation in accuracy of observations during daytime and at night performed by the merchant ships. It will be necessary in the future to give considerations on a method to correct the observation values on wave cycles taken by the merchant ship, and on a correction method in which both of the wave cycles and the wave heights are corrected simultaneously to make the observation values of the merchant ship equal to those of the observation ships. Thus, the observation values reported by general merchant ships in a large number every year will have to be utilized more effectively. 11 refs., 21 figs., 2 tabs.

Financial Rogue Waves

International Nuclear Information System (INIS)

Yan Zhenya

2010-01-01

We analytically give the financial rogue waves in the nonlinear option pricing model due to Ivancevic, which is nonlinear wave alternative of the Black-Scholes model. These rogue wave solutions may he used to describe the possible physical mechanisms for rogue wave phenomenon in financial markets and related fields.

Three-dimensional stability of solitary kinetic Alfven waves and ion-acoustic waves

International Nuclear Information System (INIS)

Ghosh, G.; Das, K.P.

1994-01-01

Starting from a set of equations that lead to a linear dispersion relation coupling kinetic Alfven waves and ion-acoustic waves, three-dimensional KdV equations are derived for these waves. These equations are then used to investigate the three-dimensional stability of solitary kinetic Alfven waves and ion-acoustic waves by the small-k perturbation expansion method of Rowlands and Infeld. For kinetic Alfven waves it is found that there is instability if the direction of the plane-wave perturbation lies inside a cone, and the growth rate of the instability attains a maximum when the direction of the perturbation lies in the plane containing the external magnetic field and the direction of propagation of the solitary wave. For ion-acoustic waves the growth rate of instability attains a maximum when the direction of the perturbation lies in a plane perpendicular to the direction of propagation of the solitary wave. (Author)

Photon wave function

OpenAIRE

Bialynicki-Birula, Iwo

2005-01-01

Photon wave function is a controversial concept. Controversies stem from the fact that photon wave functions can not have all the properties of the Schroedinger wave functions of nonrelativistic wave mechanics. Insistence on those properties that, owing to peculiarities of photon dynamics, cannot be rendered, led some physicists to the extreme opinion that the photon wave function does not exist. I reject such a fundamentalist point of view in favor of a more pragmatic approach. In my view, t...

Electromagnetic Waves

DEFF Research Database (Denmark)

This book is dedicated to various aspects of electromagnetic wave theory and its applications in science and technology. The covered topics include the fundamental physics of electromagnetic waves, theory of electromagnetic wave propagation and scattering, methods of computational analysis......, material characterization, electromagnetic properties of plasma, analysis and applications of periodic structures and waveguide components, etc....

Tropical Cyclogenesis in a Tropical Wave Critical Layer: Easterly Waves

Science.gov (United States)

Dunkerton, T. J.; Montgomery, M. T.; Wang, Z.

2009-01-01

The development of tropical depressions within tropical waves over the Atlantic and eastern Pacific is usually preceded by a "surface low along the wave" as if to suggest a hybrid wave-vortex structure in which flow streamlines not only undulate with the waves, but form a closed circulation in the lower troposphere surrounding the low. This structure, equatorward of the easterly jet axis, is identified herein as the familiar critical layer of waves in shear flow, a flow configuration which arguably provides the simplest conceptual framework for tropical cyclogenesis resulting from tropical waves, their interaction with the mean flow, and with diabatic processes associated with deep moist convection. The recirculating Kelvin cat's eye within the critical layer represents a sweet spot for tropical cyclogenesis in which a proto-vortex may form and grow within its parent wave. A common location for storm development is given by the intersection of the wave's critical latitude and trough axis at the center of the cat's eye, with analyzed vorticity centroid nearby. The wave and vortex live together for a time, and initially propagate at approximately the same speed. In most cases this coupled propagation continues for a few days after a tropical depression is identified. For easterly waves, as the name suggests, the propagation is westward. It is shown that in order to visualize optimally the associated Lagrangian motions, one should view the flow streamlines, or stream function, in a frame of reference translating horizontally with the phase propagation of the parent wave. In this co-moving frame, streamlines are approximately equivalent to particle trajectories. The closed circulation is quasi-stationary, and a dividing streamline separates air within the cat's eye from air outside.

Spin-wave logic devices based on isotropic forward volume magnetostatic waves

International Nuclear Information System (INIS)

Klingler, S.; Pirro, P.; Brächer, T.; Leven, B.; Hillebrands, B.; Chumak, A. V.

2015-01-01

We propose the utilization of isotropic forward volume magnetostatic spin waves in modern wave-based logic devices and suggest a concrete design for a spin-wave majority gate operating with these waves. We demonstrate by numerical simulations that the proposed out-of-plane magnetized majority gate overcomes the limitations of anisotropic in-plane magnetized majority gates due to the high spin-wave transmission through the gate, which enables a reduced energy consumption of these devices. Moreover, the functionality of the out-of-plane majority gate is increased due to the lack of parasitic generation of short-wavelength exchange spin waves

Spin-wave logic devices based on isotropic forward volume magnetostatic waves

Energy Technology Data Exchange (ETDEWEB)

Klingler, S., E-mail: stefan.klingler@wmi.badw-muenchen.de; Pirro, P.; Brächer, T.; Leven, B.; Hillebrands, B.; Chumak, A. V. [Fachbereich Physik and Landesforschungszentrum OPTIMAS, Technische Universität Kaiserslautern, 67663 Kaiserslautern (Germany)

2015-05-25

We propose the utilization of isotropic forward volume magnetostatic spin waves in modern wave-based logic devices and suggest a concrete design for a spin-wave majority gate operating with these waves. We demonstrate by numerical simulations that the proposed out-of-plane magnetized majority gate overcomes the limitations of anisotropic in-plane magnetized majority gates due to the high spin-wave transmission through the gate, which enables a reduced energy consumption of these devices. Moreover, the functionality of the out-of-plane majority gate is increased due to the lack of parasitic generation of short-wavelength exchange spin waves.

Making structured metals transparent for ultrabroadband electromagnetic waves and acoustic waves

International Nuclear Information System (INIS)

Fan, Ren-Hao; Peng, Ru-Wen; Huang, Xian-Rong; Wang, Mu

2015-01-01

In this review, we present our recent work on making structured metals transparent for broadband electromagnetic waves and acoustic waves via excitation of surface waves. First, we theoretically show that one-dimensional metallic gratings can become transparent and completely antireflective for extremely broadband electromagnetic waves by relying on surface plasmons or spoof surface plasmons. Second, we experimentally demonstrate that metallic gratings with narrow slits are highly transparent for broadband terahertz waves at oblique incidence and high transmission efficiency is insensitive to the metal thickness. Further, we significantly develop oblique metal gratings transparent for broadband electromagnetic waves (including optical waves and terahertz ones) under normal incidence. In the third, we find the principles of broadband transparency for structured metals can be extended from one-dimensional metallic gratings to two-dimensional cases. Moreover, similar phenomena are found in sonic artificially metallic structures, which present the transparency for broadband acoustic waves. These investigations provide guidelines to develop many novel materials and devices, such as transparent conducting panels, antireflective solar cells, and other broadband metamaterials and stealth technologies. - Highlights: • Making structured metals transparent for ultrabroadband electromagnetic waves. • Non-resonant excitation of surface plasmons or spoof surface plasmons. • Sonic artificially metallic structures transparent for broadband acoustic waves

Making structured metals transparent for ultrabroadband electromagnetic waves and acoustic waves

Energy Technology Data Exchange (ETDEWEB)

Fan, Ren-Hao [National Laboratory of Solid State Microstructures and School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093 (China); Peng, Ru-Wen, E-mail: rwpeng@nju.edu.cn [National Laboratory of Solid State Microstructures and School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093 (China); Huang, Xian-Rong [Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439 (United States); Wang, Mu [National Laboratory of Solid State Microstructures and School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093 (China)

2015-07-15

In this review, we present our recent work on making structured metals transparent for broadband electromagnetic waves and acoustic waves via excitation of surface waves. First, we theoretically show that one-dimensional metallic gratings can become transparent and completely antireflective for extremely broadband electromagnetic waves by relying on surface plasmons or spoof surface plasmons. Second, we experimentally demonstrate that metallic gratings with narrow slits are highly transparent for broadband terahertz waves at oblique incidence and high transmission efficiency is insensitive to the metal thickness. Further, we significantly develop oblique metal gratings transparent for broadband electromagnetic waves (including optical waves and terahertz ones) under normal incidence. In the third, we find the principles of broadband transparency for structured metals can be extended from one-dimensional metallic gratings to two-dimensional cases. Moreover, similar phenomena are found in sonic artificially metallic structures, which present the transparency for broadband acoustic waves. These investigations provide guidelines to develop many novel materials and devices, such as transparent conducting panels, antireflective solar cells, and other broadband metamaterials and stealth technologies. - Highlights: • Making structured metals transparent for ultrabroadband electromagnetic waves. • Non-resonant excitation of surface plasmons or spoof surface plasmons. • Sonic artificially metallic structures transparent for broadband acoustic waves.

Focusing Leaky Waves: A Class of Electromagnetic Localized Waves with Complex Spectra

Science.gov (United States)

Fuscaldo, Walter; Comite, Davide; Boesso, Alessandro; Baccarelli, Paolo; Burghignoli, Paolo; Galli, Alessandro

2018-05-01

Localized waves, i.e., the wide class of limited-diffraction, limited-dispersion solutions to the wave equation are generally characterized by real wave numbers. We consider the role played by localized waves with generally complex "leaky" wave numbers. First, the impact of the imaginary part of the wave number (i.e., the leakage constant) on the diffractive (spatial broadening) features of monochromatic localized solutions (i.e., beams) is rigorously evaluated. Then general conditions are derived to show that only a restricted class of spectra (either real or complex) allows for generating a causal localized wave. It turns out that backward leaky waves fall into this category. On this ground, several criteria for the systematic design of wideband radiators, namely, periodic radial waveguides based on backward leaky waves, are established in the framework of leaky-wave theory. An effective design method is proposed to minimize the frequency dispersion of the proposed class of devices and the impact of the "leakage" on the dispersive (temporal broadening) features of polychromatic localized solutions (i.e., pulses) is accounted for. Numerical results corroborate the concept, clearly highlighting the advantages and limitations of the leaky-wave approach for the generation of localized pulses at millimeter-wave frequencies, where energy focusing is in high demand in modern applications.

Gabor Wave Packet Method to Solve Plasma Wave Equations

International Nuclear Information System (INIS)

Pletzer, A.; Phillips, C.K.; Smithe, D.N.

2003-01-01

A numerical method for solving plasma wave equations arising in the context of mode conversion between the fast magnetosonic and the slow (e.g ion Bernstein) wave is presented. The numerical algorithm relies on the expansion of the solution in Gaussian wave packets known as Gabor functions, which have good resolution properties in both real and Fourier space. The wave packets are ideally suited to capture both the large and small wavelength features that characterize mode conversion problems. The accuracy of the scheme is compared with a standard finite element approach

Heat waves in the United States: mortality risk during heat waves and effect modification by heat wave characteristics in 43 U.S. communities.

Science.gov (United States)

Anderson, G Brooke; Bell, Michelle L

2011-02-01

Devastating health effects from recent heat waves, and projected increases in frequency, duration, and severity of heat waves from climate change, highlight the importance of understanding health consequences of heat waves. We analyzed mortality risk for heat waves in 43 U.S. cities (1987-2005) and investigated how effects relate to heat waves' intensity, duration, or timing in season. Heat waves were defined as ≥ 2 days with temperature ≥ 95th percentile for the community for 1 May through 30 September. Heat waves were characterized by their intensity, duration, and timing in season. Within each community, we estimated mortality risk during each heat wave compared with non-heat wave days, controlling for potential confounders. We combined individual heat wave effect estimates using Bayesian hierarchical modeling to generate overall effects at the community, regional, and national levels. We estimated how heat wave mortality effects were modified by heat wave characteristics (intensity, duration, timing in season). Nationally, mortality increased 3.74% [95% posterior interval (PI), 2.29-5.22%] during heat waves compared with non-heat wave days. Heat wave mortality risk increased 2.49% for every 1°F increase in heat wave intensity and 0.38% for every 1-day increase in heat wave duration. Mortality increased 5.04% (95% PI, 3.06-7.06%) during the first heat wave of the summer versus 2.65% (95% PI, 1.14-4.18%) during later heat waves, compared with non-heat wave days. Heat wave mortality impacts and effect modification by heat wave characteristics were more pronounced in the Northeast and Midwest compared with the South. We found higher mortality risk from heat waves that were more intense or longer, or those occurring earlier in summer. These findings have implications for decision makers and researchers estimating health effects from climate change.

Layout of wave gauge array for estimation of 3D waves

DEFF Research Database (Denmark)

Jakobsen, Morten Møller; Frigaard, Peter

2012-01-01

Wave gauge array are commonly used to estimate significant wave properties of multi-directional waves. The objective of this study is to gain insight into which parameters influence the accuracy of an array. The approach chosen is to determine the accuracy of an array by comparing generated waves...

A multimodal wave spectrum-based approach for statistical downscaling of local wave climate

Science.gov (United States)

Hegermiller, Christie; Antolinez, Jose A A; Rueda, Ana C.; Camus, Paula; Perez, Jorge; Erikson, Li; Barnard, Patrick; Mendez, Fernando J.

2017-01-01

Characterization of wave climate by bulk wave parameters is insufficient for many coastal studies, including those focused on assessing coastal hazards and long-term wave climate influences on coastal evolution. This issue is particularly relevant for studies using statistical downscaling of atmospheric fields to local wave conditions, which are often multimodal in large ocean basins (e.g. the Pacific). Swell may be generated in vastly different wave generation regions, yielding complex wave spectra that are inadequately represented by a single set of bulk wave parameters. Furthermore, the relationship between atmospheric systems and local wave conditions is complicated by variations in arrival time of wave groups from different parts of the basin. Here, we address these two challenges by improving upon the spatiotemporal definition of the atmospheric predictor used in statistical downscaling of local wave climate. The improved methodology separates the local wave spectrum into “wave families,” defined by spectral peaks and discrete generation regions, and relates atmospheric conditions in distant regions of the ocean basin to local wave conditions by incorporating travel times computed from effective energy flux across the ocean basin. When applied to locations with multimodal wave spectra, including Southern California and Trujillo, Peru, the new methodology improves the ability of the statistical model to project significant wave height, peak period, and direction for each wave family, retaining more information from the full wave spectrum. This work is the base of statistical downscaling by weather types, which has recently been applied to coastal flooding and morphodynamic applications.

Modeling of Mud-Wave Interaction: Mud-Induced Wave Transport & Wave-Induced Mud Transport

National Research Council Canada - National Science Library

Winterwerp, Johan C

2007-01-01

.... Also a new rheological model has been proposed to describe liquefaction of soft mud by waves, and the subsequent strength recovery after the passage of the waves. A scheme is presented on how to implement these formulations in Delft3D.

Experimental Measurement of Wave Field Variations around Wave Energy Converter Arrays

OpenAIRE

O'Boyle, Louise; Elsäßer, Björn; Whittaker, Trevor

2017-01-01

Wave energy converters (WECs) inherently extract energy from incident waves. For wave energy to become a significant power provider in the future, large farms of WECs will be required. This scale of energy extraction will increase the potential for changes in the local wave field and coastal environment. Assessment of these effects is necessary to inform decisions on the layout of wave farms for optimum power output and minimum environmental impact, as well as on potential site selection. An ...

Internal Waves and Wave Attractors in Enceladus' Subsurface Ocean

Science.gov (United States)

van Oers, A. M.; Maas, L. R.; Vermeersen, B. L. A.

2016-12-01

One of the most peculiar features on Saturn moon Enceladus is its so-called tiger stripe pattern at the geologically active South Polar Terrain (SPT), as first observed in detail by the Cassini spacecraft early 2005. It is generally assumed that the four almost parallel surface lines that constitute this pattern are faults in the icy surface overlying a confined salty water reservoir. In 2013, we formulated the original idea [Vermeersen et al., AGU Fall Meeting 2013, abstract #P53B-1848] that the tiger stripe pattern is formed and maintained by induced, tidally and rotationally driven, wave-attractor motions in the ocean underneath the icy surface of the tiger-stripe region. Such wave-attractor motions are observed in water tank experiments in laboratories on Earth and in numerical experiments [Maas et al., Nature, 338, 557-561, 1997; Drijfhout and Maas, J. Phys. Oceanogr., 37, 2740-2763, 2007; Hazewinkel et al., Phys. Fluids, 22, 107102, 2010]. Numerical simulations show the persistence of wave attractors for a range of ocean shapes and stratifications. The intensification of the wave field near the location of the surface reflections of wave attractors has been numerically and experimentally confirmed. We measured the forces a wave attractor exerts on a solid surface, near a reflection point. These reflection points would correspond to the location of the tiger stripes. Combining experiments and numerical simulations we conclude that (1) wave attractors can exist in Enceladus' subsurface sea, (2) their shape can be matched to the tiger stripes, (3) the wave attractors cause a localized force at the water-ice boundaries, (4) this force could have been large enough to contribute to fracturing the ice and (5) the wave attractors localize energy (and particles) and cause dissipation along its path, helping explain Enceladus' enigmatic heat output at the tiger stripes.

Beating HF waves to generate VLF waves in the ionosphere

Science.gov (United States)

Kuo, Spencer; Snyder, Arnold; Kossey, Paul; Chang, Chia-Lie; Labenski, John

2012-03-01

Beat-wave generation of very low frequency (VLF) waves by two HF heaters in the ionosphere is formulated theoretically and demonstrated experimentally. The heater-induced differential thermal pressure force and ponderomotive force, which dominate separately in the D and F regions of the ionosphere, drive an electron current for the VLF emission. A comparison, applying appropriate ionospheric parameters shows that the ponderomotive force dominates in beat-wave generation of VLF waves. Three experiments, one in the nighttime in the absence of D and E layers and two in the daytime in the presence of D and E layers, were performed. X mode HF heaters of slightly different frequencies were transmitted at CW full power. VLF waves at 10 frequencies ranging from 3.5 to 21.5 kHz were generated. The frequency dependencies of the daytime and nighttime radiation intensities are quite similar, but the nighttime radiation is much stronger than the daytime one at the same radiation frequency. The intensity ratio is as large as 9 dB at 11.5 kHz. An experiment directly comparing VLF waves generated by the beat-wave approach and by the amplitude modulation (AM) approach was also conducted. The results rule out the likely contribution of the AM mechanism acting on the electrojet and indicate that beat-wave in the VLF range prefers to be generated in the F region of the ionosphere through the ponderomotive nonlinearity, consistent with the theory. In the nighttime experiment, the ionosphere was underdense to the HF heaters, suggesting a likely setting for effective beat-wave generation of VLF waves by the HF heaters.

Lagrangian analysis of nonlinear wave-wave interactions in bounded plasmas

International Nuclear Information System (INIS)

Carr, A.R.

1979-01-01

In a weakly turbulent nonlinear wave-supporting medium, one of the important nonlinear processes which may occur is resonant three-wave interaction. Whitham's averaged Lagrangian method provides a general formulation of wave evolution laws which is easily adapted to nonlinear dispersive media. In this thesis, the strength of nonlinear interactions between three coherent, axisymmetric, low frequency, magnetohydrodynamic (Alfven) waves propagating in resonance along a cold cylindrical magnetized plasma column is calculated. Both a uniform and a parabolic density distribution have been considered. To account for a non-zero plasma temperature, pressure effects have been included. Distinctive features of the work are the use of cylindrical geometry, the presence of a finite rather than an infinite axial magnetic field, the treatment of a parabolic density distribution, and the inclusion of both ion and electron contributions in all expressions. Two astrophysical applications of the presented theory have been considered. In the first, the possibility of resonant three-wave coupling between geomagnetic micropulsations, which propagate as Alfven or magnetosonic waves along the Earth's magnetic field lines, has been investigated. The second case is the theory of energy transport through the solar chromosphere by upward propagating magnetohydrodynamic waves, which may then couple to heavily damped waves in the corona, causing the observed excess heating in that region

The Wave Dragon

DEFF Research Database (Denmark)

Sørensen, H. C.; Hansen, R.; Friis-Madsen, E.

2000-01-01

The Wave Dragon is an offshore wave energy converter of the overtopping type, utilizing a patented wave reflector design to focus the waves towards a ramp, and the overtopping is used for electricity production through a set of Kaplan/propeller hydro turbines. During the last 2 years, excessive...... design an testing has been performed on a scale 1:50 model of the Wave Dragon, and on a scale 1:3:5 model turbine. Thus survivability, overtopping, hydraulic response, turbine performance and feasibility have been verified....

Langmuir wave turbulence generated by electromagnetic waves in the laboratory and the ionosphere

International Nuclear Information System (INIS)

Lee, M.C.; Riddolls, R.J.; Moriarty, D.T.; Dalrymple, N.E.; Rowlands, M.J.

1996-01-01

The authors will present some recent results of the laboratory experiments at MIT, using a large plasma device known as the Versatile Toroidal Facility (VTF). These experiments are aimed at cross-checking the ionospheric plasma heating experiments at Arecibo, Puerto Rico using an HF heating facility (heater). The plasma phenomenon under investigation is the spectral characteristic of Langmuir wave turbulence produced by ordinary (o-mode) electromagnetic pump waves. The Langmuir waves excited by o-mode heaters waves at Arecibo have both a frequency-upshifted spectrum and a frequency-downshifted (viz., cascading) spectrum. While the cascading spectrum can be well explained in terms of the parametric decay instability (PDI), the authors have interpreted the frequency-upshifted Langmuir waves to be anti-Stokes Langmuir waves produced by a nonlinear scattering process as follows. Lower hybrid waves creates presumably by lightning-induced whistler waves can scatter nonlinearly the PDI-excited mother langmuir waves, yielding obliquely propagating langmuir waves with frequencies as the summation of the mother Langmuir wave frequencies and the lower hybrid wave frequencies. This suggested process has been confirmed in the laboratory experiments, that can reproduce the characteristic spectra of Langmuir wave turbulence observed in the Arecibo experiments

Parametric analysis of change in wave number of surface waves

Directory of Open Access Journals (Sweden)

Tadić Ljiljana

2015-01-01

Full Text Available The paper analyzes the dependence of the change wave number of materials soil constants, ie the frequency of the waves. The starting point in this analysis cosists of wave equation and dynamic stiffness matrix of soil.

Propagation-invariant waves in acoustic, optical, and radio-wave fields

OpenAIRE

Salo, Janne

2003-01-01

The physical phenomena considered in this thesis are associated with electromagnetic and acoustic waves that propagate in free space or in homogeneous media without diffraction. The concept of rotationally periodic wave propagation is introduced in the first journal article included in the thesis and it is subsequently used to analyse waves that avoid diffractive deterioration by repeatedly returning to their initial shape, possibly rotated around the optical axis. Such waves constitute an es...

Traveling waves and conservation laws for highly nonlinear wave equations modeling Hertz chains

Science.gov (United States)

Przedborski, Michelle; Anco, Stephen C.

2017-09-01

A highly nonlinear, fourth-order wave equation that models the continuum theory of long wavelength pulses in weakly compressed, homogeneous, discrete chains with a general power-law contact interaction is studied. For this wave equation, all solitary wave solutions and all nonlinear periodic wave solutions, along with all conservation laws, are derived. The solutions are explicitly parameterized in terms of the asymptotic value of the wave amplitude in the case of solitary waves and the peak of the wave amplitude in the case of nonlinear periodic waves. All cases in which the solution expressions can be stated in an explicit analytic form using elementary functions are worked out. In these cases, explicit expressions for the total energy and total momentum for all solutions are obtained as well. The derivation of the solutions uses the conservation laws combined with an energy analysis argument to reduce the wave equation directly to a separable first-order differential equation that determines the wave amplitude in terms of the traveling wave variable. This method can be applied more generally to other highly nonlinear wave equations.

Hydraulic Response of the Wave Energy Converter Wave Dragon in Nissum Bredning

DEFF Research Database (Denmark)

Kofoed, Jens Peter; Frigaard, Peter

This report deals with the hydraulic performance of the wave energy converter Wave Dragon, Nissum Bredning prototype.......This report deals with the hydraulic performance of the wave energy converter Wave Dragon, Nissum Bredning prototype....

Tropical cyclogenesis in a tropical wave critical layer: easterly waves

Directory of Open Access Journals (Sweden)

T. J. Dunkerton

2009-08-01

Full Text Available The development of tropical depressions within tropical waves over the Atlantic and eastern Pacific is usually preceded by a "surface low along the wave" as if to suggest a hybrid wave-vortex structure in which flow streamlines not only undulate with the waves, but form a closed circulation in the lower troposphere surrounding the low. This structure, equatorward of the easterly jet axis, is identified herein as the familiar critical layer of waves in shear flow, a flow configuration which arguably provides the simplest conceptual framework for tropical cyclogenesis resulting from tropical waves, their interaction with the mean flow, and with diabatic processes associated with deep moist convection. The recirculating Kelvin cat's eye within the critical layer represents a sweet spot for tropical cyclogenesis in which a proto-vortex may form and grow within its parent wave. A common location for storm development is given by the intersection of the wave's critical latitude and trough axis at the center of the cat's eye, with analyzed vorticity centroid nearby. The wave and vortex live together for a time, and initially propagate at approximately the same speed. In most cases this coupled propagation continues for a few days after a tropical depression is identified. For easterly waves, as the name suggests, the propagation is westward. It is shown that in order to visualize optimally the associated Lagrangian motions, one should view the flow streamlines, or stream function, in a frame of reference translating horizontally with the phase propagation of the parent wave. In this co-moving frame, streamlines are approximately equivalent to particle trajectories. The closed circulation is quasi-stationary, and a dividing streamline separates air within the cat's eye from air outside. The critical layer equatorward of the easterly jet axis is important to tropical cyclogenesis because its cat's eye provides (i a region of

Physics of waves

CERN Document Server

Elmore, William C

1985-01-01

Because of the increasing demands and complexity of undergraduate physics courses (atomic, quantum, solid state, nuclear, etc.), it is often impossible to devote separate courses to the classic wave phenomena of optics, acoustics, and electromagnetic radiation. This brief comprehensive text helps alleviate the problem with a unique overview of classical wave theory in one volume.By examining a sequence of concrete and specific examples (emphasizing the physics of wave motion), the authors unify the study of waves, developing abstract and general features common to all wave motion. The fundam

Wave-particle dualism in matter wave interferometry

International Nuclear Information System (INIS)

Rauch, H.

1984-01-01

Neutron interferometry is a unique tool for investigations in the field of particle-wave dualism because massive elementary particles behave like waves within the interferometer. The invention of perfect crystal neutron interferometers providing widely separated coherent beams stimulated a great variety of experiments with matter waves in the field of basic quantum mechanics. The phase of the spatial and spinor wave function become a measurable quantity and can be influenced individually. High degrees of coherence and high order interferences have been observed by this technique. The 4π-symmetry of a spinor wave function and the mutual modulation of nuclear and magnetic phase shifts have been measured in the past. Recent experiments dealt with polarized neutron beams, which are handled to realize the spin-superposition of two oppositionally polarized subbeams resulting in final polarization perpendicular to both initial beam polarizations. The different action on the coherent beams of static and dynamic flippers have been visualized. Monolithic multicrystal arrangements in Laue position can also be used to achieve an extremely high energy (10 -9 eV) or angular resolution (0.001 sec of arc). This feature is based on the Pendelloesung interference within the perfect crystal. A transverse coherence length up to 6.5 mm is deduced from single slit diffraction experiments. (Auth.)

Wave Dragon

DEFF Research Database (Denmark)

Tedd, James; Kofoed, Jens Peter; Knapp, W.

2006-01-01

Wave Dragon is a floating wave energy converter working by extracting energy principally by means of overtopping of waves into a reservoir. A 1:4.5 scale prototype has been sea tested for 20 months. This paper presents results from testing, experiences gained and developments made during this ext......Wave Dragon is a floating wave energy converter working by extracting energy principally by means of overtopping of waves into a reservoir. A 1:4.5 scale prototype has been sea tested for 20 months. This paper presents results from testing, experiences gained and developments made during...... this extended period. The prototype is highly instrumented. The overtopping characteristic and the power produced are presented here. This has enabled comparison between the prototype and earlier results from both laboratory model and computer simulation. This gives the optimal operating point and the expected...... power of the device. The project development team has gained much soft experience from working in the harsh offshore environment. In particular the effect of marine growth in the draft tubes of the turbines has been investigated. The control of the device has been a focus for development as is operates...

Kinematics and dynamics of green water on a fixed platform in a large wave basin in focusing wave and random wave conditions

Science.gov (United States)

Chuang, Wei-Liang; Chang, Kuang-An; Mercier, Richard

2018-06-01

Green water kinematics and dynamics due to wave impingements on a simplified geometry, fixed platform were experimentally investigated in a large, deep-water wave basin. Both plane focusing waves and random waves were employed in the generation of green water. The focusing wave condition was designed to create two consecutive plunging breaking waves with one impinging on the frontal vertical wall of the fixed platform, referred as wall impingement, and the other directly impinging on the deck surface, referred as deck impingement. The random wave condition was generated using the JONSWAP spectrum with a significant wave height approximately equal to the freeboard. A total of 179 green water events were collected in the random wave condition. By examining the green water events in random waves, three different flow types are categorized: collapse of overtopping wave, fall of bulk water, and breaking wave crest. The aerated flow velocity was measured using bubble image velocimetry, while the void fraction was measured using fiber optic reflectometry. For the plane focusing wave condition, measurements of impact pressure were synchronized with the flow velocity and void fraction measurements. The relationship between the peak pressures and the pressure rise times is examined. For the high-intensity impact in the deck impingement events, the peak pressures are observed to be proportional to the aeration levels. The maximum horizontal velocities in the green water events in random waves are well represented by the lognormal distribution. Ritter's solution is shown to quantitatively describe the green water velocity distributions under both the focusing wave condition and the random wave condition. A prediction equation for green water velocity distribution under random waves is proposed.

Gravitational wave astronomy

CERN Multimedia

CERN. Geneva

2016-01-01

In the past year, the LIGO-Virgo Collaboration announced the first secure detection of gravitational waves. This discovery heralds the beginning of gravitational wave astronomy: the use of gravitational waves as a tool for studying the dense and dynamical universe. In this talk, I will describe the full spectrum of gravitational waves, from Hubble-scale modes, through waves with periods of years, hours and milliseconds. I will describe the different techniques one uses to measure the waves in these bands, current and planned facilities for implementing these techniques, and the broad range of sources which produce the radiation. I will discuss what we might expect to learn as more events and sources are measured, and as this field matures into a standard part of the astronomical milieu.

2D full-wave simulation of waves in space and tokamak plasmas

Directory of Open Access Journals (Sweden)

Kim Eun-Hwa

2017-01-01

Full Text Available Simulation results using a 2D full-wave code (FW2D for space and NSTX fusion plasmas are presented. The FW2D code solves the cold plasma wave equations using the finite element method. The wave code has been successfully applied to describe low frequency waves in planetary magnetospheres (i.e., dipole geometry and the results include generation and propagation of externally driven ultra-low frequency waves via mode conversion at Mercury and mode coupling, refraction and reflection of internally driven field-aligned propagating left-handed electromagnetic ion cyclotron (EMIC waves at Earth. In this paper, global structure of linearly polarized EMIC waves is examined and the result shows such resonant wave modes can be localized near the equatorial plane. We also adopt the FW2D code to tokamak geometry and examine radio frequency (RF waves in the scape-off layer (SOL of tokamaks. By adopting the rectangular and limiter boundary, we compare the results with existing AORSA simulations. The FW2D code results for the high harmonic fast wave heating case on NSTX with a rectangular vessel boundary shows excellent agreement with the AORSA code.

2D full-wave simulation of waves in space and tokamak plasmas

Science.gov (United States)

Kim, Eun-Hwa; Bertelli, Nicola; Johnson, Jay; Valeo, Ernest; Hosea, Joel

2017-10-01

Simulation results using a 2D full-wave code (FW2D) for space and NSTX fusion plasmas are presented. The FW2D code solves the cold plasma wave equations using the finite element method. The wave code has been successfully applied to describe low frequency waves in planetary magnetospheres (i.e., dipole geometry) and the results include generation and propagation of externally driven ultra-low frequency waves via mode conversion at Mercury and mode coupling, refraction and reflection of internally driven field-aligned propagating left-handed electromagnetic ion cyclotron (EMIC) waves at Earth. In this paper, global structure of linearly polarized EMIC waves is examined and the result shows such resonant wave modes can be localized near the equatorial plane. We also adopt the FW2D code to tokamak geometry and examine radio frequency (RF) waves in the scape-off layer (SOL) of tokamaks. By adopting the rectangular and limiter boundary, we compare the results with existing AORSA simulations. The FW2D code results for the high harmonic fast wave heating case on NSTX with a rectangular vessel boundary shows excellent agreement with the AORSA code.

Wave-particle interaction and Hamiltonian dynamics investigated in a traveling wave tube

International Nuclear Information System (INIS)

Doveil, Fabrice; Macor, Alessandro

2006-01-01

For wave-particle interaction studies, the one-dimensional (1-D) beam-plasma system can be advantageously replaced by a Traveling Wave Tube (TWT). This led us to a detailed experimental analysis of the self-consistent interaction between unstable waves and a small either cold or warm beam. More recently, a test electron beam has been used to observe its non-self-consistent interaction with externally excited wave(s). The velocity distribution function of the electron beam is investigated with a trochoidal energy analyzer that records the beam energy distribution at the output of the TWT. An arbitrary waveform generator is used to launch a prescribed spectrum of waves along the slow wave structure (a 4 m long helix) of the TWT. The nonlinear synchronization of particles by a single wave responsible for Landau damping is observed. The resonant velocity domain associated to a single wave is also observed, as well as the transition to large-scale chaos when the resonant domains of two waves and their secondary resonances overlap leading to a typical 'devil's staircase' behavior. A new strategy for the control of chaos is tested

Magnetospheric plasma waves

International Nuclear Information System (INIS)

Shawhan, S.D.

1977-01-01

A brief history of plasma wave observations in the Earth's magnetosphere is recounted and a classification of the identified plasma wave phenomena is presented. The existence of plasma waves is discussed in terms of the characteristic frequencies of the plasma, the energetic particle populations and the proposed generation mechanisms. Examples are given for which plasmas waves have provided information about the plasma parameters and particle characteristics once a reasonable theory has been developed. Observational evidence and arguments by analogy to the observed Earth plasma wave processes are used to identify plasma waves that may be significant in other planetary magnetospheres. The similarities between the observed characteristics of the terrestrial kilometric radiation and radio bursts from Jupiter, Saturn and possibly Uranus are stressed. Important scientific problems concerning plasma wave processes in the solar system and beyond are identified and discussed. Models for solar flares, flare star radio outbursts and pulsars include elements which are also common to the models for magnetospheric radio bursts. Finally, a listing of the research and development in terms of instruments, missions, laboratory experiments, theory and computer simulations needed to make meaningful progress on the outstanding scientific problems of plasma wave research is given. (Auth.)

Real time wave measurements and wave hindcasting in deep waters

Digital Repository Service at National Institute of Oceanography (India)

Anand, N.M.; Mandal, S.; SanilKumar, V.; Nayak, B.U.

Deep water waves off Karwar (lat. 14~'45.1'N, long. 73~'34.8'E) at 75 m water depth pertaining to peak monsoon period have been measured using a Datawell waverider buoy. Measured wave data show that the significant wave height (Hs) predominantly...

Wave energy patterns of counterpulsation: a novel approach with wave intensity analysis.

Science.gov (United States)

Lu, Pong-Jeu; Yang, Chi-Fu Jeffrey; Wu, Meng-Yu; Hung, Chun-Hao; Chan, Ming-Yao; Hsu, Tzu-Cheng

2011-11-01

In counterpulsation, diastolic augmentation increases coronary blood flow and systolic unloading reduces left ventricular afterload. We present a new approach with wave intensity analysis to revisit and explain counterpulsation principles. In an acute porcine model, a standard intra-aortic balloon pump was placed in descending aorta in 4 pigs. We measured pressure and velocity with probes in left anterior descending artery and aorta during and without intra-aortic balloon pump assistance. Wave intensities of aortic and left coronary waves were derived from pressure and flow measurements with synchronization correction. We identified predominating waves in counterpulsation. In the aorta, during diastolic augmentation, intra-aortic balloon inflation generated a backward compression wave, with a "pushing" effect toward the aortic root that translated to a forward compression wave into coronary circulation. During systolic unloading, intra-aortic balloon pump deflation generated a backward expansion wave that "sucked" blood from left coronary bed into the aorta. While this backward expansion wave translated to reduced left ventricular afterload, the "sucking" effect resulted in left coronary blood steal, as demonstrated by a forward expansion wave in left anterior descending coronary flow. The waves were sensitive to inflation and deflation timing, with just 25 ms delay from standard deflation timing leading to weaker forward expansion wave and less coronary regurgitation. Intra-aortic balloon pumps generate backward-traveling waves that predominantly drive aortic and coronary blood flow during counterpulsation. Wave intensity analysis of arterial circulations may provide a mechanism to explain diastolic augmentation and systolic unloading of intra-aortic balloon pump counterpulsation. Copyright © 2011 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

A hydrodynamic model of nearshore waves and wave-induced currents

Directory of Open Access Journals (Sweden)

Ahmed Khaled Seif

2011-09-01

Full Text Available In This study develops a quasi-three dimensional numerical model of wave driven coastal currents with accounting the effects of the wave-current interaction and the surface rollers. In the wave model, the current effects on wave breaking and energy dissipation are taken into account as well as the wave diffraction effect. The surface roller associated with wave breaking was modeled based on a modification of the equations by Dally and Brown (1995 and Larson and Kraus (2002. Furthermore, the quasi-three dimensional model, which based on Navier-Stokes equations, was modified in association with the surface roller effect, and solved using frictional step method. The model was validated by data sets obtained during experiments on the Large Scale Sediment Transport Facility (LSTF basin and the Hazaki Oceanographical Research Station (HORS. Then, a model test against detached breakwater was carried out to investigate the performance of the model around coastal structures. Finally, the model was applied to Akasaki port to verify the hydrodynamics around coastal structures. Good agreements between computations and measurements were obtained with regard to the cross-shore variation in waves and currents in nearshore and surf zone.

Nonlinear Electromagnetic Waves and Spherical Arc-Polarized Waves in Space Plasmas

Science.gov (United States)

Tsurutani, B.; Ho, Christian M.; Arballo, John K.; Lakhina, Gurbax S.; Glassmeier, Karl-Heinz; Neubauer, Fritz M.

1997-01-01

We review observations of nonlinear plasma waves detected by interplanetary spacecraft. For this paper we will focus primarily on the phase-steepened properties of such waves. Plasma waves at comet Giacobini-Zinner measured by the International Cometary Explorer (ICE), at comets Halley and Grigg-Skjellerup measured by Giotto, and interplanetary Alfven waves measured by Ulysses, will be discussed and intercompared.

Waves and Tsunami Project

Science.gov (United States)

Frashure, K. M.; Chen, R. F.; Stephen, R. A.; Bolmer, T.; Lavin, M.; Strohschneider, D.; Maichle, R.; Micozzi, N.; Cramer, C.

2007-01-01

Demonstrating wave processes quantitatively in the classroom using standard classroom tools (such as Slinkys and wave tanks) can be difficult. For example, waves often travel too fast for students to actually measure amplitude or wavelength. Also, when teaching propagating waves, reflections from the ends set up standing waves, which can confuse…

Seasonal changing sand waves and the effect of surface waves

NARCIS (Netherlands)

Sterlini, Fenneke; van Dijk, Thaiënne A.G.P.; IJzer, Steven; Hulscher, Suzanne; Schüttrumpf, Holger; Tomasicchio, Guiseppe Roberto

2012-01-01

Sand waves are wavelike subaqueous sediment structures that exist in large areas in shelf seas. Due to their characteristics sand waves can severely affect human offshore activities, such as navigation. This makes it important to understand the physical processes that shape and change sand waves. In

2D full wave simulation on electromagnetic wave propagation in toroidal plasma

International Nuclear Information System (INIS)

Hojo, Hitoshi; Uruta, Go; Nakayama, Kazunori; Mase, Atsushi

2002-01-01

Global full-wave simulation on electromagnetic wave propagation in toroidal plasma with an external magnetic field imaging a tokamak configuration is performed in two dimensions. The temporal behavior of an electromagnetic wave launched into plasma from a wave-guiding region is obtained. (author)

Numerical investigation of freak waves

Science.gov (United States)

Chalikov, D.

2009-04-01

Paper describes the results of more than 4,000 long-term (up to thousands of peak-wave periods) numerical simulations of nonlinear gravity surface waves performed for investigation of properties and estimation of statistics of extreme (‘freak') waves. The method of solution of 2-D potential wave's equations based on conformal mapping is applied to the simulation of wave behavior assigned by different initial conditions, defined by JONSWAP and Pierson-Moskowitz spectra. It is shown that nonlinear wave evolution sometimes results in appearance of very big waves. The shape of freak waves varies within a wide range: some of them are sharp-crested, others are asymmetric, with a strong forward inclination. Some of them can be very big, but not steep enough to create dangerous conditions for vessels (but not for fixed objects). Initial generation of extreme waves can occur merely as a result of group effects, but in some cases the largest wave suddenly starts to grow. The growth is followed sometimes by strong concentration of wave energy around a peak vertical. It is taking place in the course of a few peak wave periods. The process starts with an individual wave in a physical space without significant exchange of energy with surrounding waves. Sometimes, a crest-to-trough wave height can be as large as nearly three significant wave heights. On the average, only one third of all freak waves come to breaking, creating extreme conditions, however, if a wave height approaches the value of three significant wave heights, all of the freak waves break. The most surprising result was discovery that probability of non-dimensional freak waves (normalized by significant wave height) is actually independent of density of wave energy. It does not mean that statistics of extreme waves does not depend on wave energy. It just proves that normalization of wave heights by significant wave height is so effective, that statistics of non-dimensional extreme waves tends to be independent

A numerical study of the wave shoaling effect on wind-wave momentum flux

Science.gov (United States)

Hao, Xuanting; Shen, Lian

2017-11-01

Momentum transfer between wind and waves is crucial to many physical processes in air-sea interactions. For decades, there has been a number of observational evidence that the surface roughness in the nearshore region is notably higher than in the open sea. In order to explain the mechanism behind this important phenomenon, in particular the wave shoaling effect on surface roughness, we conduct a series of numerical experiments using the wind-wave module of WOW (Wave-Ocean-Wind), a high-fidelity computational framework developed in house. We use prescribed monochromatic waves with linear shoaling effect incorporated, while the wind field is simulated using wall-resolved large-eddy simulation. A comparison between a shallow water wave case and deep water wave cases shows remarkably stronger wave effects on the wind for the former. Detailed analyses show that the increased surface roughness is closely associated with the increased form drag that is mainly due to the reduced wave age in wave shoaling.

On radio frequency wave induced radial transport and wave helicity

International Nuclear Information System (INIS)

Petrzilka, V.

1992-09-01

Expressions for wave induced radial transport are derived allowing simple estimates. The transport is enhanced due to the presence of poloidal magnetostatic field and in the vicinity of the ion cyclotron resonance. The direction of the wave induced transport depends also on the wave polarization. (author) 19 refs

Wave Tank Studies of Strong Modulation of Wind Ripples Due To Long Waves

Science.gov (United States)

Ermakov, S.; Sergievskaya, I.; Shchegolkov, Yu.

Modulation of wind capillary-gravity ripples due to long waves has been studied in wave tank experiment at low wind speeds using Ka-band radar. The experiments were carried out both for clean water and the water surface covered with surfactant films. It is obtained that the modulation of radar signals is quite strong and can increase with surfactant concentration and fetch. It is shown that the hydrodynamic Modulation Transfer Function (MTF) calculated for free wind ripples and taking into account the kinematic (straining) effect, variations of the wind stress and variations of surfactant concentration strongly underestimates experimental MTF-values. The effect of strong modulation is assumed to be connected with nonlinear harmonics of longer dm-cm- scale waves - bound waves ("parasitic ripples"). The intensity of bound waves depends strongly on the amplitude of decimetre-scale waves, therefore even weak modulation of the dm-scale waves due to long waves results to strong ("cascade") modulation of bound waves. Modulation of the system of "free/bound waves" is estimated using results of wave tank studies of bound waves generation and is shown to be in quali- tative agreement with experiment. This work was supported by MOD, UK via DERA Winfrith (Project ISTC 1774P) and by RFBR (Project 02-05-65102).

Near-surface compressional and shear wave speeds constrained by body-wave polarization analysis

Science.gov (United States)

Park, Sunyoung; Ishii, Miaki

2018-06-01

A new technique to constrain near-surface seismic structure that relates body-wave polarization direction to the wave speed immediately beneath a seismic station is presented. The P-wave polarization direction is only sensitive to shear wave speed but not to compressional wave speed, while the S-wave polarization direction is sensitive to both wave speeds. The technique is applied to data from the High-Sensitivity Seismograph Network in Japan, and the results show that the wave speed estimates obtained from polarization analysis are compatible with those from borehole measurements. The lateral variations in wave speeds correlate with geological and physical features such as topography and volcanoes. The technique requires minimal computation resources, and can be used on any number of three-component teleseismic recordings, opening opportunities for non-invasive and inexpensive study of the shallowest (˜100 m) crustal structures.

Skeletonized wave equation of surface wave dispersion inversion

KAUST Repository

Li, Jing; Schuster, Gerard T.

2016-01-01

We present the theory for wave equation inversion of dispersion curves, where the misfit function is the sum of the squared differences between the wavenumbers along the predicted and observed dispersion curves. Similar to wave-equation travel

Explicit wave action conservation for water waves on vertically sheared flows

Science.gov (United States)

Quinn, Brenda; Toledo, Yaron; Shrira, Victor

2016-04-01

Water waves almost always propagate on currents with a vertical structure such as currents directed towards the beach accompanied by an under-current directed back toward the deep sea or wind-induced currents which change magnitude with depth due to viscosity effects. On larger scales they also change their direction due to the Coriolis force as described by the Ekman spiral. This implies that the existing wave models, which assume vertically-averaged currents, is an approximation which is far from realistic. In recent years, ocean circulation models have significantly improved with the capability to model vertically-sheared current profiles in contrast with the earlier vertically-averaged current profiles. Further advancements have coupled wave action models to circulation models to relate the mutual effects between the two types of motion. Restricting wave models to vertically-averaged non-turbulent current profiles is obviously problematic in these cases and the primary goal of this work is to derive and examine a general wave action equation which accounts for these shortcoming. The formulation of the wave action conservation equation is made explicit by following the work of Voronovich (1976) and using known asymptotic solutions of the boundary value problem which exploit the smallness of the current magnitude compared to the wave phase velocity and/or its vertical shear and curvature. The adopted approximations are shown to be sufficient for most of the conceivable applications. This provides correction terms to the group velocity and wave action definition accounting for the shear effects, which are fitting for application to operational wave models. In the limit of vanishing current shear, the new formulation reduces to the commonly used Bretherton & Garrett (1968) no-shear wave action equation where the invariant is calculated with the current magnitude taken at the free surface. It is shown that in realistic oceanic conditions, the neglect of the vertical

Moreton wave, "EIT wave", and type II radio burst as manifestations of a single wave front

Science.gov (United States)

Kuzmenko, I. V.; Grechnev, V. V.; Uralov, A. M.

2011-12-01

We show that a Moreton wave, an "EIT wave," and a type II radio burst observed during a solar flare of July 13, 2004, might have been a manifestation of a single front of a decelerating shock wave, which appeared in an active region (AR) during a filament eruption. We propose describing a quasi-spheroidal wave propagating upward and along the solar surface by using relations known from a theory of a point-like explosion in a gas whose density changes along the radius according to a power law. By applying this law to fit the drop in density of the coronal plasma enveloping the solar active region, we first managed to bring the measured positions and velocities of surface Moreton wave and "EIT wave" into correspondence with the observed frequency drift rate of the meter type II radio burst. The exponent of the vertical coronal density falloff is selected by fitting the power law to the Newkirk and Saito empirical distributions in the height range of interest. Formal use of such a dependence in the horizontal direction with a different exponent appears to be reasonable up to distances of less than 200 Mm around the eruption center. It is possible to assume that the near-surface shock wave weakens when leaving this radius and finally the active region, entering the region of the quiet Sun where the coronal plasma density and the fast-mode speed are almost constant along the horizontal.

Parsimonious wave-equation travel-time inversion for refraction waves

KAUST Repository

Fu, Lei

2017-02-14

We present a parsimonious wave-equation travel-time inversion technique for refraction waves. A dense virtual refraction dataset can be generated from just two reciprocal shot gathers for the sources at the endpoints of the survey line, with N geophones evenly deployed along the line. These two reciprocal shots contain approximately 2N refraction travel times, which can be spawned into O(N2) refraction travel times by an interferometric transformation. Then, these virtual refraction travel times are used with a source wavelet to create N virtual refraction shot gathers, which are the input data for wave-equation travel-time inversion. Numerical results show that the parsimonious wave-equation travel-time tomogram has about the same accuracy as the tomogram computed by standard wave-equation travel-time inversion. The most significant benefit is that a reciprocal survey is far less time consuming than the standard refraction survey where a source is excited at each geophone location.

Experimental Studies on Wave Interactions of Partially Perforated Wall under Obliquely Incident Waves

Directory of Open Access Journals (Sweden)

Jong-In Lee

2014-01-01

Full Text Available This study presents wave height distribution in terms of stem wave evolution phenomena on partially perforated wall structures through three-dimensional laboratory experiments. The plain and partially perforated walls were tested to understand their effects on the stem wave evolution under the monochromatic and random wave cases with the various wave conditions, incident angle (from 10 to 40 degrees, and configurations of front and side walls. The partially perforated wall reduced the relative wave heights more effectively compared to the plain wall structure. Partially perforated walls with side walls showed a better performance in terms of wave height reduction compared to the structure without the side wall. Moreover, the relative wave heights along the wall were relatively small when the relative chamber width is large, within the range of the chamber width in this study. The wave spectra showed a frequency dependency of the wave energy dissipation. In most cases, the existence of side wall is a more important factor than the porosity of the front wall in terms of the wave height reduction even if the partially perforated wall was still effective compared to the plain wall.

Wave Induced Loads on the LEANCON Wave Energy Converter

DEFF Research Database (Denmark)

Frigaard, Peter; Kofoed, Jens Peter; Beserra, Eliab Ricarte

This report is a product of the co-operation agreement between Aalborg University and LEANCON (by Kurt Due Rasmussen) on the evaluation and development of the LEANCON wave energy converter (WEC). The work reported here has focused on evaluation of the wave induced loads on the device, based...... in the laboratory, all under the supervision of the personnel of the Wave Energy Research Group at Department of Civil Engineering, Aalborg University....

Electromagnetic ultrasonic guided waves

CERN Document Server

Huang, Songling; Li, Weibin; Wang, Qing

2016-01-01

This book introduces the fundamental theory of electromagnetic ultrasonic guided waves, together with its applications. It includes the dispersion characteristics and matching theory of guided waves; the mechanism of production and theoretical model of electromagnetic ultrasonic guided waves; the effect mechanism between guided waves and defects; the simulation method for the entire process of electromagnetic ultrasonic guided wave propagation; electromagnetic ultrasonic thickness measurement; pipeline axial guided wave defect detection; and electromagnetic ultrasonic guided wave detection of gas pipeline cracks. This theory and findings on applications draw on the author’s intensive research over the past eight years. The book can be used for nondestructive testing technology and as an engineering reference work. The specific implementation of the electromagnetic ultrasonic guided wave system presented here will also be of value for other nondestructive test developers.

Coronal Waves and Oscillations

Directory of Open Access Journals (Sweden)

Nakariakov Valery M.

2005-07-01

Full Text Available Wave and oscillatory activity of the solar corona is confidently observed with modern imaging and spectral instruments in the visible light, EUV, X-ray and radio bands, and interpreted in terms of magnetohydrodynamic (MHD wave theory. The review reflects the current trends in the observational study of coronal waves and oscillations (standing kink, sausage and longitudinal modes, propagating slow waves and fast wave trains, the search for torsional waves, theoretical modelling of interaction of MHD waves with plasma structures, and implementation of the theoretical results for the mode identification. Also the use of MHD waves for remote diagnostics of coronal plasma - MHD coronal seismology - is discussed and the applicability of this method for the estimation of coronal magnetic field, transport coefficients, fine structuring and heating function is demonstrated.

Earthquake early warning using P-waves that appear after initial S-waves

Science.gov (United States)

Kodera, Y.

2017-12-01

As measures for underprediction for large earthquakes with finite faults and overprediction for multiple simultaneous earthquakes, Hoshiba (2013), Hoshiba and Aoki (2015), and Kodera et al. (2016) proposed earthquake early warning (EEW) methods that directly predict ground motion by computing the wave propagation of observed ground motion. These methods are expected to predict ground motion with a high accuracy even for complicated scenarios because these methods do not need source parameter estimation. On the other hand, there is room for improvement in their rapidity because they predict strong motion prediction mainly based on the observation of S-waves and do not explicitly use P-wave information available before the S-waves. In this research, we propose a real-time P-wave detector to incorporate P-wave information into these wavefield-estimation approaches. P-waves within a few seconds from the P-onsets are commonly used in many existing EEW methods. In addition, we focus on P-waves that may appear in the later part of seismic waves. Kurahashi and Irikura (2013) mentioned that P-waves radiated from strong motion generation areas (SMGAs) were recognizable after S-waves of the initial rupture point in the 2011 off the Pacific coast of Tohoku earthquake (Mw 9.0) (the Tohoku-oki earthquake). Detecting these P-waves would enhance the rapidity of prediction for the peak ground motion generated by SMGAs. We constructed a real-time P-wave detector that uses a polarity analysis. Using acceleration records in boreholes of KiK-net (band-pass filtered around 0.5-10 Hz with site amplification correction), the P-wave detector performed the principal component analysis with a sliding window of 4 s and calculated P-filter values (e.g. Ross and Ben-Zion, 2014). The application to the Tohoku-oki earthquake (Mw 9.0) showed that (1) peaks of P-filter that corresponded to SMGAs appeared in several stations located near SMGAs and (2) real-time seismic intensities (Kunugi et al

Heuristic method for determining outgoing waves in many-body wave functions

International Nuclear Information System (INIS)

Redish, E.F.; Tandy, P.C.; L'Huillier, M.

1975-12-01

A new and simple method is proposed for determining the kinds of outgoing waves present in a given many-body wave function. Whether any particular wave function contains ''hidden'' rearrangement components can be determined. 1 figure

Reflectors to Focus Wave Energy

DEFF Research Database (Denmark)

Kramer, Morten; Frigaard, Peter

2005-01-01

Wave Energy Converters (WEC’s) extract wave energy from a limited area, often a single point or line even though the wave energy is generally spread out along the wave crest. By the use of wave reflectors (reflecting walls) the wave energy is effectively focused and increased by approximately 30......-50%. Clearly longer wave reflectors will focus more wave energy than shorter wave reflectors. Thus the draw back is the increased wave forces for the longer wave reflectors. In the paper a procedure for calculating the energy efficiency and the wave forces on the reflectors are described, this by use of a 3D...... boundary element method. The calculations are verified by laboratory experiments and a very good agreement is found. The paper gives estimates of possible power benefit for different wave reflector geometries and optimal geometrical design parameters are specified. On this basis inventors of WEC’s can...

The essential theory of fast wave current drive with full wave method

International Nuclear Information System (INIS)

Liu Yan; Gong Xueyu; Yang Lei; Yin Chenyan; Yin Lan

2007-01-01

The full wave numerical method is developed for analyzing fast wave current drive in the range of ion cyclotron waves in tokamak plasmas, taking into account finite larmor radius effects and parallel dispersion. the physical model, the dispersion relation on the assumption of Finite Larmor Radius (FLR) effects and the form of full wave be used for computer simulation are developed. All of the work will contribute to further study of fast wave current drive. (authors)

Short-Term Wave Forecasting for Real-Time Control of Wave Energy Converters

OpenAIRE

Fusco, Francesco; Ringwood, John

2010-01-01

Real-time control of wave energy converters requires knowledge of future incident wave elevation in order to approach optimal efficiency of wave energy extraction. We present an approach where the wave elevation is treated as a time series and it is predicted only from its past history. A comparison of a range of forecasting methodologies on real wave observations from two different locations shows how the relatively simple linear autoregressive model, which implicitly models the cyclical beh...

Elastic Wave-equation Reflection Traveltime Inversion Using Dynamic Warping and Wave Mode Decomposition

KAUST Repository

Wang, T.

2017-05-26

Elastic full waveform inversion (EFWI) provides high-resolution parameter estimation of the subsurface but requires good initial guess of the true model. The traveltime inversion only minimizes traveltime misfits which are more sensitive and linearly related to the low-wavenumber model perturbation. Therefore, building initial P and S wave velocity models for EFWI by using elastic wave-equation reflections traveltime inversion (WERTI) would be effective and robust, especially for the deeper part. In order to distinguish the reflection travletimes of P or S-waves in elastic media, we decompose the surface multicomponent data into vector P- and S-wave seismogram. We utilize the dynamic image warping to extract the reflected P- or S-wave traveltimes. The P-wave velocity are first inverted using P-wave traveltime followed by the S-wave velocity inversion with S-wave traveltime, during which the wave mode decomposition is applied to the gradients calculation. Synthetic example on the Sigbee2A model proves the validity of our method for recovering the long wavelength components of the model.

TERRAIN, City of Reedsport Levee PMR, Douglas COUNTY, OREGON

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — The Oregon Department of Geology & Mineral Industries (DOGAMI) contracted with Watershed Sciences, Inc. to collect high resolution topographic LiDAR data for...

Computational study on full-wave inversion based on the elastic wave-equation; Dansei hado hoteishiki full wave inversion no model keisan ni yoru kento

Energy Technology Data Exchange (ETDEWEB)

Uesaka, S [Kyoto University, Kyoto (Japan). Faculty of Engineering; Watanabe, T; Sassa, K [Kyoto University, Kyoto (Japan)

1997-05-27

Algorithm is constructed and a program developed for a full-wave inversion (FWI) method utilizing the elastic wave equation in seismic exploration. The FWI method is a method for obtaining a physical property distribution using the whole observed waveforms as the data. It is capable of high resolution which is several times smaller than the wavelength since it can handle such phenomena as wave reflection and dispersion. The method for determining the P-wave velocity structure by use of the acoustic wave equation does not provide information about the S-wave velocity since it does not consider S-waves or converted waves. In an analysis using the elastic wave equation, on the other hand, not only P-wave data but also S-wave data can be utilized. In this report, under such circumstances, an inverse analysis algorithm is constructed on the basis of the elastic wave equation, and a basic program is developed. On the basis of the methods of Mora and of Luo and Schuster, the correction factors for P-wave and S-wave velocities are formulated directly from the elastic wave equation. Computations are performed and the effects of the hypocenter frequency and vibration transmission direction are examined. 6 refs., 8 figs.

Study on Rayleigh Wave Inversion for Estimating Shear-wave Velocity Profile

Directory of Open Access Journals (Sweden)

T.A. Sanny

2003-05-01

Full Text Available Rayleigh wave or ground roll is a noise in seismic body waves. However, how to use this noise for soil characterization is very interesting since Rayleigh wave phase velocity is a function of compression-wave velocity, shear-wave velocity, density and layer thickness. In layered-medium Rayleigh wave velocity also depends on wavelength or frequency, and this phenomenon is called dispersion. Inversion procedure to get shear-wave velocity profile needs a priori information about the solution of the problem to limit the unknown parameters. The Lagrange multiplier method was used to solve the constrained optimization problems or well known as a smoothing parameter in inversion problems. The advantage of our inversion procedure is that it can guarantee the convergence of solution even though the field data is incomplete, insufficient, and inconsistent. The addition of smoothing parameter can reduce the time to converge. Beside numerical stability, the statistical stability is also involved in inversion procedure. In field experiment we extracted ground roll data from seismic refraction record. The dispersion curves had been constructed by applying f-k analysis and f-k dip filtering. The dispersion curves show the dependence of Rayleigh wave phase velocities in layered media to frequency. The synthetic models also demonstrate the stability and the speed of inversion procedure.

Waves in periodic medium. Atomic matter waves in light crystals

International Nuclear Information System (INIS)

Oberthaler, M. K.

1997-07-01

This work deals with the propagation of matter waves inside a periodic potential. In analogy to photon optics a potential can be described by a refractive index for matter waves. A real potential leads to a refractive spatial structure while an imaginary potential leads to an absorptive structure. A general theoretical description is given in the framework of Floquet theory. The equivalent approach of dynamical diffraction theory will be treated in detail. The analytic solution for weak potentials are given in a general form so that they are applicable for every kind of wave and medium. For our experiments an open two level atom (metastable Argon) propagating inside a standing light wave was used. Detuning the frequency of the light wave from the atomic resonance leads to a real (refractive) periodic potential. Tuning the laser exact on resonance gives rise to a pure imaginary (absorptive) periodic potential. In analogy to solid state crystals in X-ray and neutron optics we call a standing light wave a light crystal. Tuning the standing light field on resonance we demonstrated experimentally the Borrmann effect. This effect describes the increase of the total transmission through a crystal for Bragg incidence. Furthermore, we confirmed that this effect is coherent and that a sinusoidal wave field is formed inside the crystal. The nodes of the wave field were found to coincide with the maxima of absorption. For a detuned standing light field a refractive crystal was realized, for which the expected Pendelloesung effect was demonstrated. In this case the maximum of the wave field inside the crystal was found at the steepest gradient of the potential as predicted by dynamical diffraction theory. Superposing an absorptive and a refractive light crystal a complex light crystal was realized. With such a crystal the violation of Friedel's law was demonstrated in a very clear way. (author)

Gravitation Waves

CERN Multimedia

CERN. Geneva

2005-01-01

We will present a brief introduction to the physics of gravitational waves and their properties. We will review potential astrophysical sources of gravitational waves, and the physics and astrophysics that can be learned from their study. We will survey the techniques and technologies for detecting gravitational waves for the first time, including bar detectors and broadband interferometers, and give a brief status report on the international search effort, with special emphasis on the LIGO detectors and search results.

Wave-equation Migration Velocity Analysis Using Plane-wave Common Image Gathers

KAUST Repository

Guo, Bowen

2017-06-01

Wave-equation migration velocity analysis (WEMVA) based on subsurface-offset, angle domain or time-lag common image gathers (CIGs) requires significant computational and memory resources because it computes higher dimensional migration images in the extended image domain. To mitigate this problem, a WEMVA method using plane-wave CIGs is presented. Plane-wave CIGs reduce the computational cost and memory storage because they are directly calculated from prestack plane-wave migration, and the number of plane waves is often much smaller than the number of shots. In the case of an inaccurate migration velocity, the moveout of plane-wave CIGs is automatically picked by a semblance analysis method, which is then linked to the migration velocity update by a connective function. Numerical tests on two synthetic datasets and a field dataset validate the efficiency and effectiveness of this method.

Analysis of Waves

DEFF Research Database (Denmark)

Frigaard, Peter; Andersen, Thomas Lykke

The present book describes the most important aspects of wave analysis techniques applied to physical model tests. Moreover, the book serves as technical documentation for the wave analysis software WaveLab 3, cf. Aalborg University (2012). In that respect it should be mentioned that supplementary...... to the present technical documentation exists also the online help document describing the WaveLab software in detail including all the inputs and output fields. In addition to the two main authors also Tue Hald, Jacob Helm-Petersen and Morten Møller Jakobsen have contributed to the note. Their input is highly...... acknowledged. The outline of the book is as follows: • Chapter 2 and 3 describes analysis of waves in time and frequency domain. • Chapter 4 and 5 describes the separation of incident and reflected waves for the two-dimensional case. • Chapter 6 describes the estimation of the directional spectra which also...

Linear waves and instabilities

International Nuclear Information System (INIS)

Bers, A.

1975-01-01

The electrodynamic equations for small-amplitude waves and their dispersion relation in a homogeneous plasma are outlined. For such waves, energy and momentum, and their flow and transformation, are described. Perturbation theory of waves is treated and applied to linear coupling of waves, and the resulting instabilities from such interactions between active and passive waves. Linear stability analysis in time and space is described where the time-asymptotic, time-space Green's function for an arbitrary dispersion relation is developed. The perturbation theory of waves is applied to nonlinear coupling, with particular emphasis on pump-driven interactions of waves. Details of the time--space evolution of instabilities due to coupling are given. (U.S.)

Trend analysis of the wave storminess: the wave direction

Science.gov (United States)

Casas Prat, M.; Sierra, J. P.; Mösso, C.; Sánchez-Arcilla, A.

2009-09-01

Climate change has an important role in the current scientific research because of its possible future negative consequences. Concerning the climate change in the coastal engineering field, the apparent sea level rise is one of the key parameters as well as the wave height and the wave direction temporal variations. According to the IPCC (2007), during the last century the sea level has been increasing with a mean rate of 1.7 ± 0.5 mm/yr. However, at local/regional scale the tendency significantly differs from the global trend since the local pressure and wind field variations become more relevant. This appears to be particularly significant in semi-enclosed areas in the Mediterranean Sea (Cushman-Roisin et al., 2001). Even though the existing unsolved questions related to the sea level rise, the uncertainty concerning the wave height is even larger, in which stormy conditions are especially important because they are closely related to processes such as coastal erosion, flooding, etc. Therefore, it is necessary to identify possible existing tendencies of storm related parameters. In many studies, only the maximum wave height and storm duration are analysed, remaining the wave direction in a second term. Note that a possible rotation of the mean wave direction may involve severe consequences since most beach and harbour defence structures have been designed assuming a constant predominant wave incidence. Liste et al. (2004) illustrated this fact with an example in which a rotation of only 2 degrees of the mean energy flux vector could produce a beach retreat of 20 m. Another possible consequence would be a decrease of the harbour operability: increased frequency of storms in the same direction as the harbour entrance orientation would influence the navigability. The present study, which focuses in the Catalan coast (NW Mediterranean Sea), aims to improve the present knowledge of the wave storminess variations at regional scale, specially focusing on the wave

Wave Star

DEFF Research Database (Denmark)

Kramer, Morten; Brorsen, Michael; Frigaard, Peter

Denne rapport beskriver numeriske beregninger af forskellige flydergeometrier for bølgeenergianlæget Wave Star.......Denne rapport beskriver numeriske beregninger af forskellige flydergeometrier for bølgeenergianlæget Wave Star....

Gravitational shock waves and extreme magnetomaterial shock waves

International Nuclear Information System (INIS)

Lichnerowicz, Andre.

1975-01-01

Within an astrophysical context corresponding to high densities, a self-gravitating model is studied, which is the set of an extreme material medium of infinite conductivity and of a magnetic field. Corresponding shock waves generate necessarily, in general, gravitational shock waves [fr

Dependence of Wave-Breaking Statistics on Wind Stress and Wave Development

Science.gov (United States)

Katsaros, Kristina B.; Atakturk, Serhad S.

1992-01-01

Incidence of wave breaking for pure wind driven waves has been studied on Lake Washington at wind speeds up to 8 m/s. Video recordings were employed to identify and categorize the breaking events in terms of micro-scale, spilling and plunging breakers. These events were correlated with the magnitude of the wave spectrum measured with a resistance wire wave gauge and band pass filtered between 6 and 10 Hz. An equivalent percentage of breaking crests were found for spilling and plunging events. Wave forcing as measured by wind stress (or friction velocity, u(sub *), squared) and by inverse wave age, u(sub *)/Cp where Cp is the phase velocity of the waves at the peak of the frequency spectrum, were found to be good prerictors of percentage of breaking crests. When combined in a two parameter regression, those two variables gave small standard deviation and had a high correlation coefficient (66 percent). The combination of u(sub *)(exp 2) and u(sub *)/Cp can be understood in physical terms. Furthermore, for the larger values of u(sub *)(exp 2) the dependence of wave braking and wave age was stronger than at the low end of the values u(sub *)(exp 2) and u(sub *)/Cp. Thus, both the level of wave development as determined by inverse wave age, which we may term relative wind effectiveness for wave forcing and the wind forcing on the water surface determine the incidence of wave breaking. Substituting U(sub 10)(sup 3.75) (which is the dependence of whitecap cover found by Monahan and coworkers) an equivalent correlation was found to the prediction by u(sub *)(exp 2). Slightly better standard deviation value and higher correlation coefficient were found by using a Reynolds number as predictor. A two-parameter regression involving u(sub *)(exp 2) and a Reynold's number proposed by Toba and his colleagues which relates u(sub *)(exp 2) and peak wave frequency, improves the correlation even more but is less easy to interpret in physical terms. The equivalent percentage of

Viscoelastic Surface Waves

Science.gov (United States)

Borcherdt, R. D.

2007-12-01

General theoretical solutions for Rayleigh- and Love-Type surface waves in viscoelastic media describe physical characteristics of the surface waves in elastic as well as anelastic media with arbitrary amounts of intrinsic absorption. In contrast to corresponding physical characteristics for Rayleigh waves in elastic media, Rayleigh- Type surface waves in anelastic media demonstrate; 1) tilt of the particle motion orbit that varies with depth, and 2) amplitude and volumetric strain distributions with superimposed sinusoidal variations that decay exponentially with depth. Each characteristic is dependent on the amount of intrinsic absorption and the chosen model of viscoelasticity. Distinguishing characteristics of anelastic Love-Type surface waves include: 1) dependencies of the wave speed and absorption coefficient on the chosen model and amount of intrinsic absorption and frequency, and 2) superimposed sinusoidal amplitude variations with an exponential decay with depth. Numerical results valid for a variety of viscoelastic models provide quantitative estimates of the physical characteristics of both types of viscoelastic surface waves appropriate for interpretations pertinent to models of earth materials ranging from low-loss in the crust to moderate- and high-loss in water-saturated soils.

Specification of Instrumentation of Multi MW Wave Dragon Offshore Wave Energy Converter

DEFF Research Database (Denmark)

Gilling, Lasse; Kofoed, Jens Peter

Wave Dragon is a wave energy converter of the overtopping type and is described e.g. in Tedd et. al. (2006). The device has been thoroughly tested on a 1:51.8 scale model in wave laboratories and a 1:4.5 scale model deployed in Nissum Bredning, a large inland waterway in Denmark. Based on the exp......Wave Dragon is a wave energy converter of the overtopping type and is described e.g. in Tedd et. al. (2006). The device has been thoroughly tested on a 1:51.8 scale model in wave laboratories and a 1:4.5 scale model deployed in Nissum Bredning, a large inland waterway in Denmark. Based...

Incident wave, infragravity wave, and non-linear low-frequency bore evolution across fringing coral reefs

Science.gov (United States)

Storlazzi, C. D.; Griffioen, D.; Cheriton, O. M.

2016-12-01

Coral reefs have been shown to significantly attenuate incident wave energy and thus provide protection for 100s of millions of people globally. To better constrain wave dynamics and wave-driven water levels over fringing coral reefs, a 4-month deployment of wave and tide gauges was conducted across two shore-normal transects on Roi-Namur Island and two transects on Kwajalein Island in the Republic of the Marshall Islands. At all locations, although incident wave (periods 250 s) heights on the outer reef flat just inshore of the zone of wave breaking, the infragravity wave heights generally equaled the incident wave heights by the middle of the reef flat and exceeded the incident wave heights on the inner reef flat by the shoreline. The infragravity waves generally were asymmetric, positively skewed, bore-like forms with incident-band waves riding the infragravity wave crest at the head of the bore; these wave packets have similar structure to high-frequency internal waves on an internal wave bore. Bore height was shown to scale with water depth, offshore wave height, and offshore wave period. For a given tidal elevation, with increasing offshore wave heights, such bores occurred more frequently on the middle reef flat, whereas they occurred less frequently on the inner reef flat. Skewed, asymmetric waves are known to drive large gradients in velocity and shear stress that can transport material onshore. Thus, a better understanding of these low-frequency, energetic bores on reef flats is critical to forecasting how coral reef-lined coasts may respond to sea-level rise and climate change.

Interactions of solitary waves and compression/expansion waves in core-annular flows

Science.gov (United States)

Maiden, Michelle; Anderson, Dalton; El, Gennady; Franco, Nevil; Hoefer, Mark

2017-11-01

The nonlinear hydrodynamics of an initial step leads to the formation of rarefaction waves and dispersive shock waves in dispersive media. Another hallmark of these media is the soliton, a localized traveling wave whose speed is amplitude dependent. Although compression/expansion waves and solitons have been well-studied individually, there has been no mathematical description of their interaction. In this talk, the interaction of solitons and shock/rarefaction waves for interfacial waves in viscous, miscible core-annular flows are modeled mathematically and explored experimentally. If the interior fluid is continuously injected, a deformable conduit forms whose interfacial dynamics are well-described by a scalar, dispersive nonlinear partial differential equation. The main focus is on interactions of solitons with dispersive shock waves and rarefaction waves. Theory predicts that a soliton can either be transmitted through or trapped by the extended hydrodynamic state. The notion of reciprocity is introduced whereby a soliton interacts with a shock wave in a reciprocal or dual fashion as with the rarefaction. Soliton reciprocity, trapping, and transmission are observed experimentally and are found to agree with the modulation theory and numerical simulations. This work was partially supported by NSF CAREER DMS-1255422 (M.A.H.) and NSF GRFP (M.D.M.).

Interplanetary shocks, Plasma waves and turbulence, Kinetic waves and instabilities, STEREO spacecraft

Science.gov (United States)

Cohen, Z.; Breneman, A. W.; Cattell, C. A.; Davis, L.; Grul, P.; Kersten, K.; Wilson, L. B., III

2017-12-01

Determining the role of plasma waves in providing energy dissipation at shock waves is of long-standing interest. Interplanetary (IP) shocks serve as a large database of low Mach number shocks. We examine electric field waveforms captured by the Time Domain Sampler (TDS) on the STEREO spacecraft during the ramps of IP shocks, with emphasis on captures lasting 2.1 seconds. Previous work has used captures of shorter duration (66 and 131 ms on STEREO, and 17 ms on WIND), which allowed for observation of waves with maximum (minimum) frequencies of 125 kHz (15 Hz), 62.5 kHz (8 Hz), and 60 kHz (59 Hz), respectively. The maximum frequencies are comparable to 2-8 times the plasma frequency in the solar wind, enabling observation of Langmuir waves, ion acoustic, and some whistler-mode waves. The 2 second captures resolve lower frequencies ( few Hz), which allows us to analyze packet structure of the whistler-mode waves and some ion acoustic waves. The longer capture time also improves the resolvability of simultaneous wave modes and of waves with frequencies on the order of 10s of Hz. Langmuir waves, however, cannot be identified at this sampling rate, since the plasma frequency is usually higher than 3.9 kHz. IP shocks are identified from multiple databases (Helsinki heliospheric shock database at http://ipshocks.fi, and the STEREO level 3 shock database at ftp://stereoftp.nascom.nasa.gov/pub/ins_data/impact/level3/). Our analysis focuses on TDS captures in shock ramp regions, with ramp durations determined from magnetic field data taken at 8 Hz. Software is used to identify multiple wave modes in any given capture and classify waves as Langmuir, ion acoustic, whistler, lower hybrid, electron cyclotron drift instability, or electrostatic solitary waves. Relevant frequencies are determined from density and magnetic field data collected in situ. Preliminary results suggest that large amplitude (∼ 5 mV/m) ion acoustic waves are most prevalent in the ramp, in agreement with

Wave disc engine apparatus

Energy Technology Data Exchange (ETDEWEB)

Muller, Norbert; Piechna, Janusz; Sun, Guangwei; Parraga, Pablo-Francisco

2018-01-02

A wave disc engine apparatus is provided. A further aspect employs a constricted nozzle in a wave rotor channel. A further aspect provides a sharp bend between an inlet and an outlet in a fluid pathway of a wave rotor, with the bend being spaced away from a peripheral edge of the wave rotor. A radial wave rotor for generating electricity in an automotive vehicle is disclosed in yet another aspect.

Waves, currents and sediment transport modelling at the Wave Hub site

OpenAIRE

Gonzalez-Santamaria, Raul

2013-01-01

Primary supervisory team: Qingping Zou and Shunqi Pan This research project uses an integrated modelling system to investigate the effects of a wave farm on nearshore sediment transport at the Wave Hub site. The Wave Hub project is a large scale demonstration site for the development of the operation of arrays of wave energy generation devices located at the southwest coast of the UK where multiple field measurements took place. Particular attention of this study was paid to th...

Inherent Limitations in Mid-Wave and Long-Wave-IR Upconversion Detector

DEFF Research Database (Denmark)

Barh, Ajanta; Tseng, Yu-Pei; Pedersen, Christian

2017-01-01

Inherent limitations in terms of optical losses, selection of nonlinear crystal(s), detection efficiency and pumping conditions in mid-wave (3-5 µm) and long-wave (8-12 µm) infrared frequency upconversion modules are investigated in this paper.......Inherent limitations in terms of optical losses, selection of nonlinear crystal(s), detection efficiency and pumping conditions in mid-wave (3-5 µm) and long-wave (8-12 µm) infrared frequency upconversion modules are investigated in this paper....

Linear Water Waves

Science.gov (United States)

Kuznetsov, N.; Maz'ya, V.; Vainberg, B.

2002-08-01

This book gives a self-contained and up-to-date account of mathematical results in the linear theory of water waves. The study of waves has many applications, including the prediction of behavior of floating bodies (ships, submarines, tension-leg platforms etc.), the calculation of wave-making resistance in naval architecture, and the description of wave patterns over bottom topography in geophysical hydrodynamics. The first section deals with time-harmonic waves. Three linear boundary value problems serve as the approximate mathematical models for these types of water waves. The next section uses a plethora of mathematical techniques in the investigation of these three problems. The techniques used in the book include integral equations based on Green's functions, various inequalities between the kinetic and potential energy and integral identities which are indispensable for proving the uniqueness theorems. The so-called inverse procedure is applied to constructing examples of non-uniqueness, usually referred to as 'trapped nodes.'

The Virtual Wave Observatory (VWO): A Portal to Heliophysics Wave Data

Science.gov (United States)

Fung, Shing F.

2010-01-01

The Virtual Wave Observatory (VWO) is one of the discipline-oriented virtual observatories that help form the nascent NASA Heliophysics Data environment to support heliophysics research. It focuses on supporting the searching and accessing of distributed heliophysics wave data and information that are available online. Since the occurrence of a natural wave phenomenon often depends on the underlying geophysical -- i.e., context -- conditions under which the waves are generated and propagate, and the observed wave characteristics can also depend on the location of observation, VWO will implement wave-data search-by-context conditions and location, in addition to searching by time and observing platforms (both space-based and ground-based). This paper describes the VWO goals, the basic design objectives, and the key VWO functionality to be expected. Members of the heliophysics community are invited to participate in VWO development in order to ensure its usefulness and success.

Approximate Stream Function wavemaker theory for highly non-linear waves in wave flumes

DEFF Research Database (Denmark)

Zhang, H.W.; Schäffer, Hemming Andreas

2007-01-01

An approximate Stream Function wavemaker theory for highly non-linear regular waves in flumes is presented. This theory is based on an ad hoe unified wave-generation method that combines linear fully dispersive wavemaker theory and wave generation for non-linear shallow water waves. This is done...... by applying a dispersion correction to the paddle position obtained for non-linear long waves. The method is validated by a number of wave flume experiments while comparing with results of linear wavemaker theory, second-order wavemaker theory and Cnoidal wavemaker theory within its range of application....

Cycloidal Wave Energy Converter

Energy Technology Data Exchange (ETDEWEB)

Stefan G. Siegel, Ph.D.

2012-11-30

This program allowed further advancing the development of a novel type of wave energy converter, a Cycloidal Wave Energy Converter or CycWEC. A CycWEC consists of one or more hydrofoils rotating around a central shaft, and operates fully submerged beneath the water surface. It operates under feedback control sensing the incoming waves, and converts wave power to shaft power directly without any intermediate power take off system. Previous research consisting of numerical simulations and two dimensional small 1:300 scale wave flume experiments had indicated wave cancellation efficiencies beyond 95%. The present work was centered on construction and testing of a 1:10 scale model and conducting two testing campaigns in a three dimensional wave basin. These experiments allowed for the first time for direct measurement of electrical power generated as well as the interaction of the CycWEC in a three dimensional environment. The Atargis team successfully conducted two testing campaigns at the Texas A&M Offshore Technology Research Center and was able to demonstrate electricity generation. In addition, three dimensional wave diffraction results show the ability to achieve wave focusing, thus increasing the amount of wave power that can be extracted beyond what was expected from earlier two dimensional investigations. Numerical results showed wave cancellation efficiencies for irregular waves to be on par with results for regular waves over a wide range of wave lengths. Using the results from previous simulations and experiments a full scale prototype was designed and its performance in a North Atlantic wave climate of average 30kW/m of wave crest was estimated. A full scale WEC with a blade span of 150m will deliver a design power of 5MW at an estimated levelized cost of energy (LCOE) in the range of 10-17 US cents per kWh. Based on the new results achieved in the 1:10 scale experiments these estimates appear conservative and the likely performance at full scale will

Electromagnetic wave matching device

International Nuclear Information System (INIS)

Hirata, Yosuke; Mitsunaka, Yoshika; Hayashi, Ken-ichi; Ito, Yasuyuki.

1997-01-01

The present invention provides an electromagnetic wave matching capable of reducing a cost for the transmission system in a system of using electromagnetic waves for plasma heating of a thermonuclear reactor. Namely, incident electromagnetic waves are reflected by using a plurality of phase correction mirrors. The reflected electromagnetic waves are connected to an external transmission system through an exit. The phase correction mirrors have such a shape to receive a plurality of beam-like electromagnetic waves and output electromagnetic waves by the number different from the number of the received electromagnetic wave beams having a predetermined distribution. Further, at least two of the phase correction mirrors have such a shape to change the phase of the electromagnetic waves beams incident to the reflection surface of the phase correction mirrors by a predetermined amount corresponding to the position of the reflection surface. Then, the cost for transmission system can greatly be reduced. (I.S.)

Rogue waves in shallow water

Science.gov (United States)

Soomere, T.

2010-07-01

Most of the processes resulting in the formation of unexpectedly high surface waves in deep water (such as dispersive and geometrical focusing, interactions with currents and internal waves, reflection from caustic areas, etc.) are active also in shallow areas. Only the mechanism of modulational instability is not active in finite depth conditions. Instead, wave amplification along certain coastal profiles and the drastic dependence of the run-up height on the incident wave shape may substantially contribute to the formation of rogue waves in the nearshore. A unique source of long-living rogue waves (that has no analogues in the deep ocean) is the nonlinear interaction of obliquely propagating solitary shallow-water waves and an equivalent mechanism of Mach reflection of waves from the coast. The characteristic features of these processes are (i) extreme amplification of the steepness of the wave fronts, (ii) change in the orientation of the largest wave crests compared with that of the counterparts and (iii) rapid displacement of the location of the extreme wave humps along the crests of the interacting waves. The presence of coasts raises a number of related questions such as the possibility of conversion of rogue waves into sneaker waves with extremely high run-up. Also, the reaction of bottom sediments and the entire coastal zone to the rogue waves may be drastic.

Band gaps and localization of surface water waves over large-scale sand waves with random fluctuations

Science.gov (United States)

Zhang, Yu; Li, Yan; Shao, Hao; Zhong, Yaozhao; Zhang, Sai; Zhao, Zongxi

2012-06-01

Band structure and wave localization are investigated for sea surface water waves over large-scale sand wave topography. Sand wave height, sand wave width, water depth, and water width between adjacent sand waves have significant impact on band gaps. Random fluctuations of sand wave height, sand wave width, and water depth induce water wave localization. However, random water width produces a perfect transmission tunnel of water waves at a certain frequency so that localization does not occur no matter how large a disorder level is applied. Together with theoretical results, the field experimental observations in the Taiwan Bank suggest band gap and wave localization as the physical mechanism of sea surface water wave propagating over natural large-scale sand waves.

Wave Engine Topping Cycle Assessment

Science.gov (United States)

Welch, Gerard E.

1996-01-01

The performance benefits derived by topping a gas turbine engine with a wave engine are assessed. The wave engine is a wave rotor that produces shaft power by exploiting gas dynamic energy exchange and flow turning. The wave engine is added to the baseline turboshaft engine while keeping high-pressure-turbine inlet conditions, compressor pressure ratio, engine mass flow rate, and cooling flow fractions fixed. Related work has focused on topping with pressure-exchangers (i.e., wave rotors that provide pressure gain with zero net shaft power output); however, more energy can be added to a wave-engine-topped cycle leading to greater engine specific-power-enhancement The energy addition occurs at a lower pressure in the wave-engine-topped cycle; thus the specific-fuel-consumption-enhancement effected by ideal wave engine topping is slightly lower than that effected by ideal pressure-exchanger topping. At a component level, however, flow turning affords the wave engine a degree-of-freedom relative to the pressure-exchanger that enables a more efficient match with the baseline engine. In some cases, therefore, the SFC-enhancement by wave engine topping is greater than that by pressure-exchanger topping. An ideal wave-rotor-characteristic is used to identify key wave engine design parameters and to contrast the wave engine and pressure-exchanger topping approaches. An aerodynamic design procedure is described in which wave engine design-point performance levels are computed using a one-dimensional wave rotor model. Wave engines using various wave cycles are considered including two-port cycles with on-rotor combustion (valved-combustors) and reverse-flow and through-flow four-port cycles with heat addition in conventional burners. A through-flow wave cycle design with symmetric blading is used to assess engine performance benefits. The wave-engine-topped turboshaft engine produces 16% more power than does a pressure-exchanger-topped engine under the specified topping

Hydrodynamic loads of sea waves on horizontal elements of berths with wave quenching chambers

Directory of Open Access Journals (Sweden)

Leshchenko Sergey Vladimirovich

2014-05-01

Full Text Available In the process of hydraulic structures design, in particular berths with wave cancelling structures, which serve to decrease the wave impact on structures, there appears a problem of vertical wave hydrodynamic loads calculation on floor slabs. In the existing normative documents there are no requirements on calculating vertical wave loads on the horizontal floor slabs of open-type structures (enveloping, mooring, approach trestles, etc. and stairs of sloping-staired open-type structures. A mathematical model is proposed for calculation of the vertical wave loads on the floor slab through moorings. The model is based on the theory of jet impact on a solid surface. The width of the wave crest, striking in the overlap of the pier, and its vertical velocity is determined by the linear wave theory. The coefficient of transmission of waves through wave quenching chambers is calculated according to the previously developed methods. Vertical wave loading is adjusted based on the ratio of the wave length and width of the overlay. Model validation is performed according to the hydraulic modelling interaction of waves with through berths in the port of Tuapse. 7 variants of their design were considered. Data mapping mathematical and hydraulic modeling showed them a close match.

A maximally informative version of inelastic scattering of electromagnetic waves by Langmuir waves

International Nuclear Information System (INIS)

Erofeev, V. I.

2015-01-01

The concept of informativeness of nonlinear plasma physics scenarios is explained. Natural ideas of developing highly informative models of plasma kinetics are spelled out. A maximally informative version of inelastic scattering of electromagnetic waves by Langmuir waves in a weakly turbulent inhomogeneous plasma is developed with consideration of possible changes in wave polarization. In addition, a new formula for wave drift in spatial positions and wave vectors is derived. New scenarios of the respective wave drift and inelastic scattering are compared with the previous visions. The results indicate the need for further revision of the traditional understanding of nonlinear plasma phenomena

Travelling wave solutions of generalized coupled Zakharov–Kuznetsov and dispersive long wave equations

Directory of Open Access Journals (Sweden)

M. Arshad

Full Text Available In this manuscript, we constructed different form of new exact solutions of generalized coupled Zakharov–Kuznetsov and dispersive long wave equations by utilizing the modified extended direct algebraic method. New exact traveling wave solutions for both equations are obtained in the form of soliton, periodic, bright, and dark solitary wave solutions. There are many applications of the present traveling wave solutions in physics and furthermore, a wide class of coupled nonlinear evolution equations can be solved by this method. Keywords: Traveling wave solutions, Elliptic solutions, Generalized coupled Zakharov–Kuznetsov equation, Dispersive long wave equation, Modified extended direct algebraic method

Wave-equation dispersion inversion

KAUST Repository

Li, Jing

2016-12-08

We present the theory for wave-equation inversion of dispersion curves, where the misfit function is the sum of the squared differences between the wavenumbers along the predicted and observed dispersion curves. The dispersion curves are obtained from Rayleigh waves recorded by vertical-component geophones. Similar to wave-equation traveltime tomography, the complicated surface wave arrivals in traces are skeletonized as simpler data, namely the picked dispersion curves in the phase-velocity and frequency domains. Solutions to the elastic wave equation and an iterative optimization method are then used to invert these curves for 2-D or 3-D S-wave velocity models. This procedure, denoted as wave-equation dispersion inversion (WD), does not require the assumption of a layered model and is significantly less prone to the cycle-skipping problems of full waveform inversion. The synthetic and field data examples demonstrate that WD can approximately reconstruct the S-wave velocity distributions in laterally heterogeneous media if the dispersion curves can be identified and picked. The WD method is easily extended to anisotropic data and the inversion of dispersion curves associated with Love waves.

Propagation of waves

CERN Document Server

David, P

2013-01-01

Propagation of Waves focuses on the wave propagation around the earth, which is influenced by its curvature, surface irregularities, and by passage through atmospheric layers that may be refracting, absorbing, or ionized. This book begins by outlining the behavior of waves in the various media and at their interfaces, which simplifies the basic phenomena, such as absorption, refraction, reflection, and interference. Applications to the case of the terrestrial sphere are also discussed as a natural generalization. Following the deliberation on the diffraction of the "ground? wave around the ear

Non-diffractive waves

CERN Document Server

Hernandez-Figueroa, Hugo E; Recami, Erasmo

2013-01-01

This continuation and extension of the successful book ""Localized Waves"" by the same editors brings together leading researchers in non-diffractive waves to cover the most important results in their field and as such is the first to present the current state.The well-balanced presentation of theory and experiments guides readers through the background of different types of non-diffractive waves, their generation, propagation, and possible applications. The authors include a historical account of the development of the field, and cover different types of non-diffractive waves, including Airy

Heat Waves

Science.gov (United States)

Heat Waves Dangers we face during periods of very high temperatures include: Heat cramps: These are muscular pains and spasms due ... that the body is having trouble with the heat. If a heat wave is predicted or happening… - ...

An Extreme-ultraviolet Wave Generating Upward Secondary Waves in a Streamer-like Solar Structure

Science.gov (United States)

Zheng, Ruisheng; Chen, Yao; Feng, Shiwei; Wang, Bing; Song, Hongqiang

2018-05-01

Extreme-ultraviolet (EUV) waves, spectacular horizontally propagating disturbances in the low solar corona, always trigger horizontal secondary waves (SWs) when they encounter the ambient coronal structure. We present the first example of upward SWs in a streamer-like structure after the passing of an EUV wave. This event occurred on 2017 June 1. The EUV wave happened during a typical solar eruption including a filament eruption, a coronal mass ejection (CME), and a C6.6 flare. The EUV wave was associated with quasi-periodic fast propagating (QFP) wave trains and a type II radio burst that represented the existence of a coronal shock. The EUV wave had a fast initial velocity of ∼1000 km s‑1, comparable to high speeds of the shock and the QFP wave trains. Intriguingly, upward SWs rose slowly (∼80 km s‑1) in the streamer-like structure after the sweeping of the EUV wave. The upward SWs seemed to originate from limb brightenings that were caused by the EUV wave. All of the results show that the EUV wave is a fast-mode magnetohydrodynamic (MHD) shock wave, likely triggered by the flare impulses. We suggest that part of the EUV wave was probably trapped in the closed magnetic fields of the streamer-like structure, and upward SWs possibly resulted from the release of slow-mode trapped waves. It is believed that the interplay of the strong compression of the coronal shock and the configuration of the streamer-like structure is crucial for the formation of upward SWs.

Antiferromagnetism and d-wave superconductivity in (doped) Mott insulators: A wave function approach

OpenAIRE

Weng, Z. Y.; Zhou, Y.; Muthukumar, V. N.

2003-01-01

We propose a class of wave functions that provide a unified description of antiferromagnetism and d-wave superconductivity in (doped) Mott insulators. The wave function has a Jastrow form and prohibits double occupancies. In the absence of holes, the wave function describes antiferromagnetism accurately. Off diagonal long range order develops at finite doping and the superconducting order parameter has d-wave symmetry. We also show how nodal quasiparticles and neutral spin excitations can be ...

Temporal change in shallow subsurface P- and S-wave velocities and S-wave anisotropy inferred from coda wave interferometry

Science.gov (United States)

Yamamoto, M.; Nishida, K.; Takeda, T.

2012-12-01

Recent progresses in theoretical and observational researches on seismic interferometry reveal the possibility to detect subtle change in subsurface seismic structure. This high sensitivity of seismic interferometry to the medium properties may thus one of the most important ways to directly observe the time-lapse behavior of shallow crustal structure. Here, using the coda wave interferometry, we show the co-seismic and post-seismic changes in P- and S-wave velocities and S-wave anisotropy associated with the 2011 off the Pacific coast of Tohoku earthquake (M9.0). In this study, we use the acceleration data recorded at KiK-net stations operated by NIED, Japan. Each KiK-net station has a borehole whose typical depth is about 100m, and two three-component accelerometers are installed at the top and bottom of the borehole. To estimate the shallow subsurface P- and S-wave velocities and S-wave anisotropy between two sensors and their temporal change, we select about 1000 earthquakes that occurred between 2004 and 2012, and extract body waves propagating between borehole sensors by computing the cross-correlation functions (CCFs) of 3 x 3 component pairs. We use frequency bands of 2-4, 4-8, 8-16 Hz in our analysis. Each averaged CCF shows clear wave packets traveling between borehole sensors, and their travel times are almost consistent with those of P- and S-waves calculated from the borehole log data. Until the occurrence of the 2011 Tohoku earthquake, the estimated travel time at each station is rather stable with time except for weak seasonal/annual variation. On the other hand, the 2011 Tohoku earthquake and its aftershocks cause sudden decrease in the S-wave velocity at most of the KiK-net stations in eastern Japan. The typical value of S-wave velocity changes, which are measured by the time-stretching method, is about 5-15%. After this co-seismic change, the S-wave velocity gradually recovers with time, and the recovery continues for over one year following the

Chiral heat wave and mixing of magnetic, vortical and heat waves in chiral media

International Nuclear Information System (INIS)

Chernodub, M.N.

2016-01-01

We show that a hot rotating fluid of relativistic chiral fermions possesses a new gapless collective mode associated with coherent propagation of energy density and chiral density waves along the axis of rotation. This mode, which we call the Chiral Heat Wave, emerges due to a mixed gauge-gravitational anomaly. At finite density the Chiral Heat Wave couples to the Chiral Vortical Wave while in the presence of an external magnetic field it mixes with the Chiral Magnetic Wave. The coupling of the Chiral Magnetic and Chiral Vortical Waves is also demonstrated. We find that the coupled waves — which are coherent fluctuations of the vector, axial and energy currents — have generally different velocities compared to the velocities of the individual waves.

FIRST SIMULTANEOUS OBSERVATION OF AN H{alpha} MORETON WAVE, EUV WAVE, AND FILAMENT/PROMINENCE OSCILLATIONS

Energy Technology Data Exchange (ETDEWEB)

Asai, Ayumi; Isobe, Hiroaki [Unit of Synergetic Studies for Space, Kyoto University, Yamashina, Kyoto 607-8471 (Japan); Ishii, Takako T.; Kitai, Reizaburo; Ichimoto, Kiyoshi; UeNo, Satoru; Nagata, Shin' ichi; Morita, Satoshi; Nishida, Keisuke; Shibata, Kazunari [Kwasan and Hida Observatories, Kyoto University, Yamashina, Kyoto 607-8471 (Japan); Shiota, Daikou [Advanced Science Institute, RIKEN, Wako, Saitama 351-0198 (Japan); Oi, Akihito [College of Science, Ibaraki University, Mito, Ibaraki 310-8512 (Japan); Akioka, Maki, E-mail: asai@kwasan.kyoto-u.ac.jp [Hiraiso Solar Observatory, National Institute of Information and Communications Technology, Hitachinaka, Ibaraki 311-1202 (Japan)

2012-02-15

We report on the first simultaneous observation of an H{alpha} Moreton wave, the corresponding EUV fast coronal waves, and a slow and bright EUV wave (typical EIT wave). We observed a Moreton wave, associated with an X6.9 flare that occurred on 2011 August 9 at the active region NOAA 11263, in the H{alpha} images taken by the Solar Magnetic Activity Research Telescope at Hida Observatory of Kyoto University. In the EUV images obtained by the Atmospheric Imaging Assembly on board the Solar Dynamic Observatory we found not only the corresponding EUV fast 'bright' coronal wave, but also the EUV fast 'faint' wave that is not associated with the H{alpha} Moreton wave. We also found a slow EUV wave, which corresponds to a typical EIT wave. Furthermore, we observed, for the first time, the oscillations of a prominence and a filament, simultaneously, both in the H{alpha} and EUV images. To trigger the oscillations by the flare-associated coronal disturbance, we expect a coronal wave as fast as the fast-mode MHD wave with the velocity of about 570-800 km s{sup -1}. These velocities are consistent with those of the observed Moreton wave and the EUV fast coronal wave.

Questions about elastic waves

CERN Document Server

Engelbrecht, Jüri

2015-01-01

This book addresses the modelling of mechanical waves by asking the right questions about them and trying to find suitable answers. The questions follow the analytical sequence from elementary understandings to complicated cases, following a step-by-step path towards increased knowledge. The focus is on waves in elastic solids, although some examples also concern non-conservative cases for the sake of completeness. Special attention is paid to the understanding of the influence of microstructure, nonlinearity and internal variables in continua. With the help of many mathematical models for describing waves, physical phenomena concerning wave dispersion, nonlinear effects, emergence of solitary waves, scales and hierarchies of waves as well as the governing physical parameters are analysed. Also, the energy balance in waves and non-conservative models with energy influx are discussed. Finally, all answers are interwoven into the canvas of complexity.

B-waves revisited

Directory of Open Access Journals (Sweden)

Andreas Spiegelberg

2016-12-01

With the still unmet need for a clinically acceptable method for acquiring intracranial compliance, and the revival of ICP waveform analysis, B-waves are moving back into the research focus. Herein we provide a concise review of the literature on B-waves, including a critical assessment of non-invasive methods for obtaining B-wave surrogates.

Wave Dragon MW

DEFF Research Database (Denmark)

Kofoed, Jens Peter; Frigaard, Peter

Wave Dragon is a wave energy converter of the overtopping type. The device has been thoroughly tested on a 1:51.8 scale model in wave laboratories and a 1:4.5 scale model deployed in Nissum Bredning, a large inland waterway in Denmark. Based on the experience gained a full scale, multi MW prototype...

Alfven wave resonances and flow induced by nonlinear Alfven waves in a stratified atmosphere

International Nuclear Information System (INIS)

Stark, B. A.; Musielak, Z. E.; Suess, S. T.

1996-01-01

A nonlinear, time-dependent, ideal MHD code has been developed and used to compute the flow induced by nonlinear Alfven waves propagating in an isothermal, stratified, plane-parallel atmosphere. The code is based on characteristic equations solved in a Lagrangian frame. Results show that resonance behavior of Alfven waves exists in the presence of a continuous density gradient and that the waves with periods corresponding to resonant peaks exert considerably more force on the medium than off-resonance periods. If only off-peak periods are considered, the relationship between the wave period and induced longitudinal velocity shows that short period WKB waves push more on the background medium than longer period, non-WKB, waves. The results also show the development of the longitudinal waves induced by finite amplitude Alfven waves. Wave energy transferred to the longitudinal mode may provide a source of localized heating

Let your banner wave? : Antecedents and performance implications of retailers' private-label branding strategies

NARCIS (Netherlands)

Keller, Kristopher; Dekimpe, Marnik; Geyskens, Inge

The authors study the drivers and performance implications of retailers’ branding strategies for their premium and economy private-label tiers. Retailers can opt for store-banner branding – and use their store-banner name and/or logo to reveal their ownership – or they can use stand-alone branding –

Development of the Wave Energy Converter -Wave Dragon

DEFF Research Database (Denmark)

Kofoed, Jens Peter; Frigaard, Peter; Sørensen, Hans Christian

2000-01-01

2Over the years wave energy has gradually been brought into focus, as it has become clear that the fossil energy resources are limited, and cause large environmental problems, e.g. CO2 pollution. On this background a number of different wave energy converters have been proposed. In Denmark the go...

Experimental investigation of gravity wave turbulence and of non-linear four wave interactions..

Science.gov (United States)

Berhanu, Michael

2017-04-01

Using the large basins of the Ecole Centrale de Nantes (France), non-linear interactions of gravity surface waves are experimentally investigated. In a first part we study statistical properties of a random wave field regarding the insights from the Wave Turbulence Theory. In particular freely decaying gravity wave turbulence is generated in a closed basin. No self-similar decay of the spectrum is observed, whereas its Fourier modes decay first as a time power law due to nonl-inear mechanisms, and then exponentially due to linear viscous damping. We estimate the linear, non-linear and dissipative time scales to test the time scale separation. By estimation of the mean energy flux from the initial decay of wave energy, the Kolmogorov-Zakharov constant of the weak turbulence theory is evaluated. In a second part, resonant interactions of oblique surface gravity waves in a large basin are studied. We generate two oblique waves crossing at an acute angle. These mother waves mutually interact and give birth to a resonant wave whose properties (growth rate, resonant response curve and phase locking) are fully characterized. All our experimental results are found in good quantitative agreement with four-wave interaction theory. L. Deike, B. Miquel, P. Gutiérrez, T. Jamin, B. Semin, M. Berhanu, E. Falcon and F. Bonnefoy, Role of the basin boundary conditions in gravity wave turbulence, Journal of Fluid Mechanics 781, 196 (2015) F. Bonnefoy, F. Haudin, G. Michel, B. Semin, T. Humbert, S. Aumaître, M. Berhanu and E. Falcon, Observation of resonant interactions among surface gravity waves, Journal of Fluid Mechanics (Rapids) 805, R3 (2016)

Frequency and wavenumber selective excitation of spin waves through coherent energy transfer from elastic waves

OpenAIRE

Hashimoto, Yusuke; Bossini, Davide; Johansen, Tom H.; Saitoh, Eiji; Kirilyuk, Andrei; Rasing, Theo

2017-01-01

Using spin-wave tomography (SWaT), we have investigated the excitation and the propagation dynamics of optically-excited magnetoelastic waves, i.e. hybridized modes of spin waves and elastic waves, in a garnet film. By using time-resolved SWaT, we reveal the excitation dynamics of magnetoelastic waves through coherent-energy transfer between optically-excited pure-elastic waves and spin waves via magnetoelastic coupling. This process realizes frequency and wavenumber selective excitation of s...

Kinesthetic Transverse Wave Demonstration

Science.gov (United States)

Pantidos, Panagiotis; Patapis, Stamatis

2005-09-01

This is a variation on the String and Sticky Tape demonstration "The Wave Game," suggested by Ron Edge. A group of students stand side by side, each one holding a card chest high with both hands. The teacher cues the first student to begin raising and lowering his card. When he starts lowering his card, the next student begins to raise his. As succeeding students move their cards up and down, a wave such as that shown in the figure is produced. To facilitate the process, students' motions were synchronized with the ticks of a metronome (without such synchronization it was nearly impossible to generate a satisfactory wave). Our waves typically had a frequency of about 1 Hz and a wavelength of around 3 m. We videotaped the activity so that the students could analyze the motions. The (17-year-old) students had not received any prior instruction regarding wave motion and did not know beforehand the nature of the exercise they were about to carry out. During the activity they were asked what a transverse wave is. Most of them quickly realized, without teacher input, that while the wave propagated horizontally, the only motion of the transmitting medium (them) was vertical. They located the equilibrium points of the oscillations, the crests and troughs of the waves, and identified the wavelength. The teacher defined for them the period of the oscillations of the motion of a card to be the total time for one cycle. The students measured this time and then several asserted that it was the same as the wave period. Knowing the length of the waves and the number of waves per second, the next step can easily be to find the wave speed.

Hierarchical wave functions revisited

International Nuclear Information System (INIS)

Li Dingping.

1997-11-01

We study the hierarchical wave functions on a sphere and on a torus. We simplify some wave functions on a sphere or a torus using the analytic properties of wave functions. The open question, the construction of the wave function for quasi electron excitation on a torus, is also solved in this paper. (author)

Developing de Broglie Wave

Directory of Open Access Journals (Sweden)

Zheng-Johansson J. X.

2006-10-01

Full Text Available The electromagnetic component waves, comprising together with their generating oscillatory massless charge a material particle, will be Doppler shifted when the charge hence particle is in motion, with a velocity v, as a mere mechanical consequence of the source motion. We illustrate here that two such component waves generated in opposite directions and propagating at speed c between walls in a one-dimensional box, superpose into a traveling beat wave of wavelength Λd=vcΛ and phase velocity c2/v+v which resembles directly L. de Broglie’s hypothetic phase wave. This phase wave in terms of transmitting the particle mass at the speed v and angular frequency Ωd= 2πv/Λd, with Λd and Ωd obeying the de Broglie relations, represents a de Broglie wave. The standing-wave function of the de Broglie (phase wave and its variables for particle dynamics in small geometries are equivalent to the eigen-state solutions to Schrödinger equation of an identical system.

Vector financial rogue waves

International Nuclear Information System (INIS)

Yan, Zhenya

2011-01-01

The coupled nonlinear volatility and option pricing model presented recently by Ivancevic is investigated, which generates a leverage effect, i.e., stock volatility is (negatively) correlated to stock returns, and can be regarded as a coupled nonlinear wave alternative of the Black–Scholes option pricing model. In this Letter, we analytically propose vector financial rogue waves of the coupled nonlinear volatility and option pricing model without an embedded w-learning. Moreover, we exhibit their dynamical behaviors for chosen different parameters. The vector financial rogue wave (rogon) solutions may be used to describe the possible physical mechanisms for the rogue wave phenomena and to further excite the possibility of relative researches and potential applications of vector rogue waves in the financial markets and other related fields. -- Highlights: ► We investigate the coupled nonlinear volatility and option pricing model. ► We analytically present vector financial rogue waves. ► The vector financial rogue waves may be used to describe the extreme events in financial markets. ► This results may excite the relative researches and potential applications of vector rogue waves.

Ocean wave characteristic in the Sunda Strait using Wave Spectrum Model

Science.gov (United States)

Rachmayani, R.; Ningsih, N. S.; Adiprabowo, S. R.; Nurfitri, S.

2018-03-01

The wave characteristics including significant wave height and direction, seas and swell in the Sunda Strait are analyzed seasonally to provide marine weather information. This is crucial for establishing secured marine activities between islands of Sumatera and Java. Ocean wave characteristics in the Sunda Strait are simulated for one year (July 1996–June 1977) by using SWAN numerical model. The ocean wave characteristics in the Sunda Strait are divided into three areas of interest; southern, centre and northern part of the Sunda Strait. Despite a weaker local wind, the maximum significant wave height is captured at the southern part with its height of 2.6 m in November compared to other seasonally months. This is associated with the dominated swell from the Indian Ocean contributes on wave energy toward the Sunda Strait. The 2D spectrum analysis exhibits the monthly wave characteristic at southern part that is dominated by seas along the year and swell propagating from the Indian Ocean to the Sunda Strait during December to February (northwest monsoon), May, and November. Seas and swell at northern part of the Sunda Strait are apprehended weaker compared to other parts of the Sunda Strait due to its location is farther from the Indian Ocean.

Universal instability of dust ion-sound waves and dust-acoustic waves

International Nuclear Information System (INIS)

Tsytovich, V.N.; Watanabe, K.

2002-01-01

It is shown that the dust ion-sound waves (DISW) and the dust-acoustic waves (DAW) are universally unstable for wave numbers less than some critical wave number. The basic dusty plasma state is assumed to be quasi-neutral with balance of the plasma particle absorption on the dust particles and the ionization with the rate proportional to the electron density. An analytical expression for the critical wave numbers, for the frequencies and for the growth rates of DISW and DAW are found using the hydrodynamic description of dusty plasma components with self-consistent treatment of the dust charge variations and by taking into account the change of the ion and electron distributions in the dust charging process. Most of the previous treatment do not take into account the latter process and do not treat the basic state self-consistently. The critical lengths corresponding to these critical wave numbers can be easily achieved in the existing experiments. It is shown that at the wave numbers larger than the critical ones DISW and DAW have a large damping which was not treated previously and which can be also measured. The instabilities found in the present work on their non linear stage can lead to formation of different types of dust self-organized structures. (author)

Fast wave current drive

International Nuclear Information System (INIS)

Goree, J.; Ono, M.; Colestock, P.; Horton, R.; McNeill, D.; Park, H.

1985-07-01

Fast wave current drive is demonstrated in the Princeton ACT-I toroidal device. The fast Alfven wave, in the range of high ion-cyclotron harmonics, produced 40 A of current from 1 kW of rf power coupled into the plasma by fast wave loop antenna. This wave excites a steady current by damping on the energetic tail of the electron distribution function in the same way as lower-hybrid current drive, except that fast wave current drive is appropriate for higher plasma densities

Plasma waves

National Research Council Canada - National Science Library

Swanson, D. G

1989-01-01

... Swanson, D.G. (Donald Gary), D a t e - Plasma waves. Bibliography: p. Includes index. 1. Plasma waves. QC718.5.W3S43 1989 ISBN 0-12-678955-X I. Title. 530.4'4 88-34388 Printed in the United Sta...

Unbalanced Neuronal Circuits in Addiction

OpenAIRE

Volkow, Nora D.; Wang, Gen-Jack; Tomasi, Dardo; Baler, Ruben D.

2013-01-01

Through sequential waves of drug-induced neurochemical stimulation, addiction co-opts the brain's neuronal circuits that mediate reward, motivation, , to behavioral inflexibility and a severe disruption of self-control and compulsive drug intake. Brain imaging technologies have allowed neuroscientists to map out the neural landscape of addiction in the human brain and to understand how drugs modify it.

To test photon statistics by atomic beam deflection

International Nuclear Information System (INIS)

Wang Yuzhu; Chen Yudan; Huang Weigang; Liu Liang

1985-02-01

There exists a simple relation between the photon statistics in resonance fluorescence and the statistics of the momentum transferred to an atom by a plane travelling wave [Cook, R.J., Opt. Commun., 35, 347(1980)]. Using an atomic beam deflection by light pressure, we have observed sub-Poissonian statistics in resonance fluorescence of two-level atoms. (author)

Bright and dark soliton solutions of the (3 + 1 )-dimensional ...

Indian Academy of Sciences (India)

2013-08-01

Aug 1, 2013 ... [22] S L Palacios and J M Fernandez-Diaz, Opt. Commun. 178, 457 (2000). [23] A Biswas, H Triki and M Labidi, Physics of Wave Phenomena 19(1), 24 (2011). [24] N Taghizadeh, M Mirzazadeh and S R Moosavi Noori, Appl. Appl. Math. 7(1), 175 (2012). [25] T Alagesan, A Uthayakumar and K Porsezian, ...

From the Somigliana waves to the evanescent waves

Directory of Open Access Journals (Sweden)

Pietro Caloi

2010-02-01

Full Text Available The Rayleigh equation has real coefficients; therefore, also the case of complex conjugated roots may be explained physically. The Author proves that the Somigliana waves may be formed for Poisson ratio values until 0.30543; for gradually less rigid media, they are missing altogether and degenerate into evanescent waves.

Propagation of nonlinear waves over submerged step: wave separation and subharmonic generation

Science.gov (United States)

Monsalve, Eduardo; Maurel, Agnes; Pagneux, Vincent; Petitjeans, Philippe

2015-11-01

Water waves can be described in simplified cases by the Helmholtz equation. However, even in these cases, they present a high complexity, among which their dispersive character and their nonlinearities are the subject of the present study. Using Fourier Transform Profilometry, we study experimentally the propagation of waves passing over a submerged step. Because of the small water depth after the step, the wave enters in a nonlinear regime. In the shallow water region, the second harmonic leads to two types of waves: bound waves which are slaves of the fundamental frequency with wavenumber 2 k (ω) , and free waves which propagate according to the usual dispersion relation with wavenumber k (2 ω) . Because of the presence of these two waves, beats are produced at the second harmonic with characteristic beat length. In this work, for the first time we extended this analysis to the third and higher harmonics. Next, the region after the step is limited to a finite size L with a reflecting wall. For certain frequencies and L- values, the spectral component becomes involved, with the appearance of sub harmonics. This regime is analyzed in more details, suggesting a transition to a chaotic and quasi-periodic wave behavior.

Parsimonious wave-equation travel-time inversion for refraction waves

KAUST Repository

Fu, Lei; Hanafy, Sherif M.; Schuster, Gerard T.

2017-01-01

We present a parsimonious wave-equation travel-time inversion technique for refraction waves. A dense virtual refraction dataset can be generated from just two reciprocal shot gathers for the sources at the endpoints of the survey line, with N

Dominant wave frequency and amplitude estimation for adaptive control of wave energy converters

OpenAIRE

Nguyen , Hoai-Nam; Tona , Paolino; Sabiron , Guillaume

2017-01-01

International audience; Adaptive control is of great interest for wave energy converters (WEC) due to the inherent time-varying nature of sea conditions. Robust and accurate estimation algorithms are required to improve the knowledge of the current sea state on a wave-to-wave basis in order to ensure power harvesting as close as possible to optimal behavior. In this paper, we present a simple but innovative approach for estimating the wave force dominant frequency and wave force dominant ampl...

Wave-Particle Energy Exchange Directly Observed in a Kinetic Alfven-Branch Wave

Science.gov (United States)

Gershman, Daniel J.; F-Vinas, Adolfo; Dorelli, John C.; Boardsen, Scott A. (Inventor); Avanov, Levon A.; Bellan, Paul M.; Schwartz, Steven J.; Lavraud, Benoit; Coffey, Victoria N.; Chandler, Michael O.;

Lagrangian modelling of ocean surface waves and synthetic aperture radar wave measurements

Energy Technology Data Exchange (ETDEWEB)

Fouques, Sebastien

2005-07-01

The present thesis is concerned with the estimation of the ocean wave spectrum from synthetic aperture radar imaging and the modelling of ocean surface waves using the Lagrangian formalism. The first part gives a short overview of the theories of ocean surface waves and synthetic aperture radar (SAR) whereas the second part consists of five independent publications. The first two articles investigate the influence of the radar backscatter model on the SAR imaging of ocean waves. In Article I, Monte Carlo simulations of SAR images of the ocean surface are carried out using a nonlinear backscatter model that include both specular reflection and Bragg scattering and the results are compared to simulations from the classical Hasselmann integral transform (Hasselmann and Hasselmann, 1991). It is shown that nonlinearities in the backscatter model strongly influence the imaging of range-travelling waves and that the former can suppress the range-splitting effect (Bruning et al., 1988). Furthermore, in Article II a database of Envisat-ASAR Wave Mode products co-located with directional wave spectra from the numerical model WAM and which contains range-travelling wave cases only, is set up. The WAM spectra are used as input to several ocean-to-SAR integral transforms, with various real aperture radar (RAR) models and the obtained SAR image cross-spectra are compared to the Envisat-ASAR observations. A first result is that the use of a linear backscatter model leads to a high proportion of non-physical negative backscatter values in the RAR image, as suggested by Schulz-Stellenfleth (2001). Then, a comparison between the observed SAR cross-spectra and the ones simulated through Hasselmann's integral transform reveals that only twenty percents of the observations show a range-splitting effect as strong as in the simulations. A much better agreement is obtained when using the integral transform by Schulz-Stellenfleth (2003), which is based on a nonlinear hackscatter model

Periodic waves in nonlinear metamaterials

International Nuclear Information System (INIS)

Liu, Wen-Jun; Xiao, Jing-Hua; Yan, Jie-Yun; Tian, Bo

2012-01-01

Periodic waves are presented in this Letter. With symbolic computation, equations for monochromatic waves are studied, and analytic periodic waves are obtained. Factors affecting properties of periodic waves are analyzed. Nonlinear metamaterials, with the continuous distribution of the dielectric permittivity obtained, are different from the ones with the discrete distribution. -- Highlights: ► Equations for the monochromatic waves in transverse magnetic polarization have been studied. ► Analytic periodic waves for the equations have been obtained. ► Periodic waves are theoretically presented and studied in the nonlinear metamaterials.

Full wave simulations of fast wave mode conversion and lower hybrid wave propagation in tokamaks

DEFF Research Database (Denmark)

Wright, J.C.; Bonoli, P.T.; Brambilla, M.

2004-01-01

Fast wave (FW) studies of mode conversion (MC) processes at the ion-ion hybrid layer in toroidal plasmas must capture the disparate scales of the FW and mode converted ion Bernstein and ion cyclotron waves. Correct modeling of the MC layer requires resolving wavelengths on the order of k...

Book review: Extreme ocean waves

Science.gov (United States)

Geist, Eric L.

2011-01-01

‘‘Extreme Ocean Waves’’ is a collection of ten papers edited by Efim Pelinovsky and Christian Kharif that followed the April 2007 meeting of the General Assembly of the European Geosciences Union. A note on terminology: extreme waves in this volume broadly encompass different types of waves, includ- ing deep-water and shallow-water rogue waves (alternatively termed freak waves), storm surges from cyclones, and internal waves. Other types of waves such as tsunamis or rissaga (meteotsunamis) are not discussed in this volume. It is generally implied that ‘‘extreme’’ has a statistical connotation relative to the average or significant wave height specific to each type of wave. Throughout the book, in fact, the reader will find a combination of theoretical and statistical/ empirical treatment necessary for the complete examination of this subject. In the introduction, the editors underscore the importance of studying extreme waves, documenting several dramatic instances of damaging extreme waves that occurred in 2007. 

Nonlinear effects in water waves

International Nuclear Information System (INIS)

Janssen, P.A.E.M.

1989-05-01

This set of lecture notes on nonlinear effects in water waves was written on the occasion of the first ICTP course on Ocean Waves and Tides held from 26 September until 28 October 1988 in Trieste, Italy. It presents a summary and unification of my knowledge on nonlinear effects of gravity waves on an incompressible fluid without vorticity. The starting point of the theory is the Hamiltonian for water waves. The evolution equations of both weakly nonlinear, shallow water and deep water gravity waves are derived by suitable approximation of the energy of the waves, resulting in the Korteweg-de Vries equation and the Zakharov equation, respectively. Next, interesting properties of the KdV equation (solitons) and the Zakharov equation (instability of a finite amplitude wave train) are discussed in some detail. Finally, the evolution of a homogeneous, random wave field due to resonant four wave processes is considered and the importance of this process for ocean wave prediction is pointed out. 38 refs, 21 figs

ULF waves in the foreshock

Science.gov (United States)

Greenstadt, E. W.; Le, G.; Strangeway, R. J.

1995-01-01

We review our current knowledge of ULF waves in planetary foreshocks. Most of this knowledge comes from observations taken within a few Earth radii of the terrestrial bow shock. Terrestrial foreshock ULF waves can be divided into three types, large amplitude low frequency waves (approximately 30-s period), upstream propagating whistlers (1-Hz waves), and 3-s waves. The 30-s waves are apparently generated by back-streaming ion beams, while the 1-Hz waves are generated at the bow shock. The source of the 3-s waves has yet to be determined. In addition to issues concerning the source of ULF waves in the foreshock, the waves present a number of challenges, both in terms of data acquisition, and comparison with theory. The various waves have different coherence scales, from approximately 100 km to approximately 1 Earth radius. Thus multi-spacecraft separation strategies must be tailored to the phenomenon of interest. From a theoretical point of view, the ULF waves are observed in a plasma in which the thermal pressure is comparable to the magnetic pressure, and the rest-frame wave frequency can be moderate fraction of the proton gyro-frequency. This requires the use of kinetic plasma wave dispersion relations, rather than multi-fluid MHD. Lastly, and perhaps most significantly, ULF waves are used to probe the ambient plasma, with inferences being drawn concerning the types of energetic ion distributions within the foreshock. However, since most of the data were acquired close to the bow shock, the properties of the more distant foreshock have to be deduced mainly through extrapolation of the near-shock results. A general understanding of the wave and plasma populations within the foreshock, their interrelation, and evolution, requires additional data from the more distant foreshock.

A Simple Wave Driver

Science.gov (United States)

Temiz, Burak Kagan; Yavuz, Ahmet

2015-01-01

This study was done to develop a simple and inexpensive wave driver that can be used in experiments on string waves. The wave driver was made using a battery-operated toy car, and the apparatus can be used to produce string waves at a fixed frequency. The working principle of the apparatus is as follows: shortly after the car is turned on, the…

Spin-Wave Wave Function for Quantum Spin Models : Condensed Matter and Statistical Physics

OpenAIRE

Franjo, FRANJIC; Sandro, SORELLA; Istituto Nazionale di Fisica della Materia International School for Advance Studies; Istituto Nazionale di Fisica della Materia International School for Advance Studies

1997-01-01

We present a new approach to determine an accurate variational wave function for general quantum spin models, completely defined by a consistency requirement with the simple and well-known linear spin-wave expansion. With this wave function, it is also possible to obtain the correct behavior of the long distance correlation functions for the 1D S=1/2 antiferromagnet. In 2D the proposed spin-wave wave function represents an excellent approximation to the exact ground state of the S=1.2 XY mode...

Making waves: visualizing fluid flows

NARCIS (Netherlands)

Zweers, Wout; Zwart, Valerie; Bokhove, Onno

2013-01-01

We explore the visualization of violent wave dynamics and erosion by waves and jets in laser-cut reliefs, laser engravings, and three-dimensional printing. For this purpose we built table-top experiments to cast breaking waves, and also explored the creation of extreme or rogue waves in larger wave

Wave Induced Stresses Measured at the Wave Dragon Nissum Bredning Prototype

DEFF Research Database (Denmark)

Corona, L.; Kofoed, Jens Peter

2006-01-01

The paper describes the wave induced loading on the overtopping based wave energy converter Wave Dragon. Focus is put on the junction between the main body and the reflector, also called the "shoulder part", where large cross sectional forces and bending moments acts. There are two main objectives...... for this paper, first to verify the FEM results obtained by Niras, Danish society in charge of the finite element modelling and structural design, and then to make a first experimental fatigue analysis of a particular part of the Wave Dragon. This last part shall be considered as an exercise for the further work...

Competing p-wave orders

International Nuclear Information System (INIS)

Donos, Aristomenis; Gauntlett, Jerome P; Pantelidou, Christiana

2014-01-01

We construct electrically charged, asymptotically AdS 5 black hole solutions that are dual to d = 4 CFTs in a superfluid phase with either p-wave or (p + ip)-wave order. The two types of black holes have non-vanishing charged two-form in the bulk and appear at the same critical temperature in the unbroken phase. Both the p-wave and the (p + ip)-wave phase can be thermodynamically preferred, depending on the mass and charge of the two-form, and there can also be first order transitions between them. The p-wave black holes have a helical structure and some of them exhibit the phenomenon of pitch inversion as the temperature is decreased. Both the p-wave and the (p + ip)-wave black holes have zero entropy density ground states at zero temperature and we identify some new ground states which exhibit scaling symmetry, including a novel scenario for the emergence of conformal symmetry in the IR. (paper)

Trend analysis of wave storminess: wave direction and its impact on harbour agitation

Directory of Open Access Journals (Sweden)

M. Casas-Prat

2010-11-01

Full Text Available In the context of wave climate variability, long-term alterations in the wave storminess pattern of the Catalan coast (northwestern Mediterranean Sea are analysed in terms of wave energy content and wave direction, on the basis of wave hindcast data (from 44-year time series. In general, no significant temporal trends are found for annual mean and maximum energy. However, the same analysis carried out separately for different wave directions reveals a remarkable increase in the storm energy of events from the south, which is partly due to a rise in the annual percentage of such storms. A case study of Tarragona Port (on the southern Catalan coast highlights the importance of including changes in wave direction in the study of potential impacts of climate change. In particular, an increase in the frequency of storms from the south leads to greater agitation inside the Port.

Impacts of wave-induced circulation in the surf zone on wave setup

Science.gov (United States)

Guérin, Thomas; Bertin, Xavier; Coulombier, Thibault; de Bakker, Anouk

2018-03-01

Wave setup corresponds to the increase in mean water level along the coast associated with the breaking of short-waves and is of key importance for coastal dynamics, as it contributes to storm surges and the generation of undertows. Although overall well explained by the divergence of the momentum flux associated with short waves in the surf zone, several studies reported substantial underestimations along the coastline. This paper investigates the impacts of the wave-induced circulation that takes place in the surf zone on wave setup, based on the analysis of 3D modelling results. A 3D phase-averaged modelling system using a vortex force formalism is applied to hindcast an unpublished field experiment, carried out at a dissipative beach under moderate to very energetic wave conditions (Hm 0 = 6m at breaking and Tp = 22s). When using an adaptive wave breaking parameterisation based on the beach slope, model predictions for water levels, short waves and undertows improved by about 30%, with errors reducing to 0.10 m, 0.10 m and 0.09 m/s, respectively. The analysis of model results suggests a very limited impact of the vertical circulation on wave setup at this dissipative beach. When extending this analysis to idealized simulations for different beach slopes ranging from 0.01 to 0.05, it shows that the contribution of the vertical circulation (horizontal and vertical advection and vertical viscosity terms) becomes more and more relevant as the beach slope increases. In contrast, for a given beach slope, the wave height at the breaking point has a limited impact on the relative contribution of the vertical circulation on the wave setup. For a slope of 0.05, the contribution of the terms associated with the vertical circulation accounts for up to 17% (i.e. a 20% increase) of the total setup at the shoreline, which provides a new explanation for the underestimations reported in previously published studies.

Conservation laws of wave action and potential enstrophy for Rossby waves in a stratified atmosphere