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Sample records for additional qaly gained

  1. A note on the estimation of the equity-efficiency trade-off for QALYs.

    PubMed

    Johannesson, M; Gerdtham, U

    1996-06-01

    In this note the veil of ignorance approach is tested as a basis for empirically determining the shape of the social welfare function for QALYs. An experiment is carried out where the participants choose between different societies that differ with respect to per capita QALYs and the distribution of QALYs. The answers are analyzed using logistic regression analysis. According to the results the respondents are willing to give up I QALY in the group with more QALYs to gain 0.45 QALYs in the group with fewer QALYs, but this trade-off is independent of the size of the difference in QALYs between the groups.

  2. QALYs, age and fairness.

    PubMed

    Kappel, Klemens; Sandøe, Peter

    1992-10-01

    ... We can therefore conclude that either we should go for equality; and in that case QALYs are unfair because they haven't got enough of an ageist bias. Or we should accept consequentialism; and in that case QALYs have just the right sort of ageist bias. No plausible case can, however, be made for the claim that QALYs have an unfair bias against old people. Other things being equal we ought when distributing resources essential for survival favour the young. This ethical claim can be supported both by reference to equality (the life-time-view) and by reference to consequentialism (and the premises that resources generally will be more useful when given to young people).

  3. Preferences, needs and QALYs.

    PubMed

    Cohen, J

    1996-10-01

    Quality Adjusted Life Years (QALYs) have become a household word among health economists. Their use as a means of comparing the value of health programmes and medical interventions has stirred up controversy in the medical profession and the academic community. In this paper, I argue that QALY analysis does not adequately take into account the differentiated nature of the health state values it measures. Specifically, it does not distinguish between needs and preferences with respect to its valuation of health states. I defend the view that needs and preferences are clearly distinguishable, and that the concept of needs cannot be dispensed with, as many health economists suggest. It is argued that the scale along which health states are measured in QALY analysis is not a continuous interval scale, but one which concerns two distinctly different value dimensions. Measuring the values of health state intervals may reveal the weighting attached to the different value dimensions. PMID:8910777

  4. The social value of a QALY: raising the bar or barring the raise?

    PubMed Central

    2011-01-01

    Background Since the inception of the National Institute for Health and Clinical Excellence (NICE) in England, there have been questions about the empirical basis for the cost-per-QALY threshold used by NICE and whether QALYs gained by different beneficiaries of health care should be weighted equally. The Social Value of a QALY (SVQ) project, reported in this paper, was commissioned to address these two questions. The results of SVQ were released during a time of considerable debate about the NICE threshold, and authors with differing perspectives have drawn on the SVQ results to support their cases. As these discussions continue, and given the selective use of results by those involved, it is important, therefore, not only to present a summary overview of SVQ, but also for those who conducted the research to contribute to the debate as to its implications for NICE. Discussion The issue of the threshold was addressed in two ways: first, by combining, via a set of models, the current UK Value of a Prevented Fatality (used in transport policy) with data on fatality age, life expectancy and age-related quality of life; and, second, via a survey designed to test the feasibility of combining respondents' answers to willingness to pay and health state utility questions to arrive at values of a QALY. Modelling resulted in values of £10,000-£70,000 per QALY. Via survey research, most methods of aggregating the data resulted in values of a QALY of £18,000-£40,000, although others resulted in implausibly high values. An additional survey, addressing the issue of weighting QALYs, used two methods, one indicating that QALYs should not be weighted and the other that greater weight could be given to QALYs gained by some groups. Summary Although we conducted only a feasibility study and a modelling exercise, neither present compelling evidence for moving the NICE threshold up or down. Some preliminary evidence would indicate it could be moved up for some types of QALY and

  5. Valuing QALYs at the end of life.

    PubMed

    Pinto-Prades, Jose-Luis; Sánchez-Martínez, Fernando-Ignacio; Corbacho, Belen; Baker, Rachel

    2014-07-01

    The possibility of weighting QALYs differently for different groups of patients has been a source of debate. Most recently, this debate has been extended to the relative value of QALYs at the end of life (EoL). The objective of this study is to provide evidence of societal preferences in relation to this topic. Three cross-sectional surveys were conducted amongst Spanish general population (n = 813). Survey 1 compared increases in life expectancy for EoL patients with health gains from temporary health problems. Survey 2 compared health gains for temporary health problems with quality of life gains at the EoL (palliative care). Survey 3 compared increases in life expectancy with quality of life gains, both for EoL patients. Preferences were elicited using Person Trade-Off (PTO) and Willingness to pay (WTP) techniques presenting two different durations of health benefit (6 and 18 months). Health benefits, measured in QALYs, were held constant in all comparisons. In survey 1 mean WTP was higher for life extending treatments than for temporary health problems and the majority of respondents prioritised life extension over temporary health problems in response to the PTO questions. In survey 2 mean WTP was higher for palliative care than for temporary health problems and 83% prioritized palliative care (for both durations) in the PTO questions. In survey 3 WTP values were higher for palliative care than for life extending treatments and more than 60% prioritized palliative care in the PTO questions. Our results suggest that QALYs gained from EoL treatments have a higher social value than QALYs gained from treatments for temporary health problems. Further, we found that people attach greater weight to improvements in quality of life than to life extension at the end of life. PMID:24820408

  6. [QALYS or not QALYS: that is the question?].

    PubMed

    Moatti, J P; Auquier, P; Le Coroller, A G; Macquart-Moulin, G

    1995-12-01

    The article discusses the proposal of some health economists to use the "cost per QALY (quality-adjusted-life year)" ratio as an universal indicator for economic assessment of medical interventions, in the so-called "cost-utility" analyses. Authors argue that QALYs are not a straightforward application of expected utility theory, which is the standard economic model of individual behaviours toward risk and uncertainty. Indeed, QALYs are compatible with economic utility theory only if individuals' preferences regarding health states satisfy certain very restrictive properties: utility independence between length of life and quality of life, constancy of the proportional trade-off between quality of life and length of life, risk neutrality towards health states, constancy through time of the utility associated with each health state. Aggregation of individual QALYs to obtain an indicator for patient groups at the societal level also raises complex equity problems. Last but not least, from the epistemological point of view, QALYs are based on the hypothesis that health interventions only affect the health of the individual and not any other aspects of his well-being. The authors conclude that the "cost per QALY" approach should be abandoned in order to avoid ambiguities that could impede the development of health economics in the medical field. PMID:8552855

  7. Exploring a new method for deriving the monetary value of a QALY.

    PubMed

    Tilling, Carl; Krol, Marieke; Attema, Arthur E; Tsuchiya, Aki; Brazier, John; van Exel, Job; Brouwer, Werner

    2016-09-01

    Several studies have sought to determine the monetary value of health gains expressed as quality adjusted life years (QALYs) gained, predominantly using willingness to pay approaches. However, willingness to pay has a number of recognized problems, most notably its insensitivity to scope. This paper presents an alternative approach to estimate the monetary value of a QALY, which is based on the time trade-off method. Moreover, it presents the results of an online study conducted in the Netherlands exploring the feasibility of this novel approach. The results seem promising, but also highlight a number of methodological problems with this approach, most notably nontrading and the elicitation of negative values. Additional research is necessary to try to overcome these problems and to determine the potential of this new approach. PMID:26289341

  8. Exploring a new method for deriving the monetary value of a QALY.

    PubMed

    Tilling, Carl; Krol, Marieke; Attema, Arthur E; Tsuchiya, Aki; Brazier, John; van Exel, Job; Brouwer, Werner

    2016-09-01

    Several studies have sought to determine the monetary value of health gains expressed as quality adjusted life years (QALYs) gained, predominantly using willingness to pay approaches. However, willingness to pay has a number of recognized problems, most notably its insensitivity to scope. This paper presents an alternative approach to estimate the monetary value of a QALY, which is based on the time trade-off method. Moreover, it presents the results of an online study conducted in the Netherlands exploring the feasibility of this novel approach. The results seem promising, but also highlight a number of methodological problems with this approach, most notably nontrading and the elicitation of negative values. Additional research is necessary to try to overcome these problems and to determine the potential of this new approach.

  9. QALYs and the capability approach.

    PubMed

    Cookson, Richard

    2005-08-01

    This explores the applicability of Sen's capability approach to the economic evaluation of health care programmes. An individual's 'capability set' describes his freedom to choose valuable activities and states of being ('functionings'). Direct estimation and valuation of capability sets is not feasible at present. Standard preference-based methods such as willingness to pay are feasible, but problematic due to the adaptive and constructed nature of individual preferences over time and under uncertainty. An alternative is to re-interpret the QALY as a cardinal and interpersonally comparable index of the value of the individual's capability set. This approach has limitations, since the link between QALYs and capabilities is not straightforward. Nevertheless, the QALY approach is recognisable as an application of the capability approach since it pays close attention to functionings, through the use of survey-based multi-attribute health state valuation instruments, and permits conceptions of value other than the traditional utilitarian ones of choice, desire-fulfilment and happiness. Furthermore, suitably re-interpreted, it can account for (i) non-separability between health and non-health components of value; and suitably modified it can also account for (ii) process attributes of care, which may have a direct effect on non-health functionings such as comfort and dignity, and (iii) sub-group diversity in the value of the same health functionings. PMID:15693028

  10. QALYs, euthanasia and the puzzle of death.

    PubMed

    Barrie, Stephen

    2015-08-01

    This paper considers the problems that arise when death, which is a philosophically difficult concept, is incorporated into healthcare metrics, such as the quality-adjusted life year (QALY). These problems relate closely to the debate over euthanasia and assisted suicide because negative QALY scores can be taken to mean that patients would be 'better off dead'. There is confusion in the literature about the meaning of 0 QALY, which is supposed to act as an 'anchor' for the surveyed preferences on which QALYs are based. In the context of the debate over euthanasia, the QALY assumes an ability to make meaningful comparisons between life-states and death. Not only is this assumption questionable, but the ethical debate is much more broad than the question of whether death is preferable to a state of living. QALYs are derived from preferences about health states, so do not necessarily reflect preferences about events (eg, dying) or actions (eg, killing). This paper presents a new kind of problem for the QALY. As it stands, the QALY provides confused and unreliable information when it reports zero or negative values, and faces further problems when it appears to recommend death. This should preclude its use in the debate over euthanasia and assisted suicide. These problems only apply where the QALY involves or seems to involve a comparison between life-states and death, and are not relevant to the more general discussion of the use of QALYs as a tool for comparing the benefits derived from treatment options.

  11. QALYs, euthanasia and the puzzle of death.

    PubMed

    Barrie, Stephen

    2015-08-01

    This paper considers the problems that arise when death, which is a philosophically difficult concept, is incorporated into healthcare metrics, such as the quality-adjusted life year (QALY). These problems relate closely to the debate over euthanasia and assisted suicide because negative QALY scores can be taken to mean that patients would be 'better off dead'. There is confusion in the literature about the meaning of 0 QALY, which is supposed to act as an 'anchor' for the surveyed preferences on which QALYs are based. In the context of the debate over euthanasia, the QALY assumes an ability to make meaningful comparisons between life-states and death. Not only is this assumption questionable, but the ethical debate is much more broad than the question of whether death is preferable to a state of living. QALYs are derived from preferences about health states, so do not necessarily reflect preferences about events (eg, dying) or actions (eg, killing). This paper presents a new kind of problem for the QALY. As it stands, the QALY provides confused and unreliable information when it reports zero or negative values, and faces further problems when it appears to recommend death. This should preclude its use in the debate over euthanasia and assisted suicide. These problems only apply where the QALY involves or seems to involve a comparison between life-states and death, and are not relevant to the more general discussion of the use of QALYs as a tool for comparing the benefits derived from treatment options. PMID:25082901

  12. Using QALYs in telehealth evaluations: a systematic review of methodology and transparency

    PubMed Central

    2014-01-01

    Background The quality-adjusted life-year (QALY) is a recognised outcome measure in health economic evaluations. QALY incorporates individual preferences and identifies health gains by combining mortality and morbidity into one single index number. A literature review was conducted to examine and discuss the use of QALYs to measure outcomes in telehealth evaluations. Methods Evaluations were identified via a literature search in all relevant databases. Only economic evaluations measuring both costs and QALYs using primary patient level data of two or more alternatives were included. Results A total of 17 economic evaluations estimating QALYs were identified. All evaluations used validated generic health related-quality of life (HRQoL) instruments to describe health states. They used accepted methods for transforming the quality scores into utility values. The methodology used varied between the evaluations. The evaluations used four different preference measures (EQ-5D, SF-6D, QWB and HUI3), and utility scores were elicited from the general population. Most studies reported the methodology used in calculating QALYs. The evaluations were less transparent in reporting utility weights at different time points and variability around utilities and QALYs. Few made adjustments for differences in baseline utilities. The QALYs gained in the reviewed evaluations varied from 0.001 to 0.118 in implying a small but positive effect of telehealth intervention on patient’s health. The evaluations reported mixed cost-effectiveness results. Conclusion The use of QALYs in telehealth evaluations has increased over the last few years. Different methodologies and utility measures have been used to calculate QALYs. A more harmonised methodology and utility measure is needed to ensure comparability across telehealth evaluations. PMID:25086443

  13. Additional solar/load ratio correlations for direct gain buildings

    SciTech Connect

    Wray, W.O.

    1980-01-01

    Solar/load ratio (SLR) correlations have been developed for two new reference direct gain designs. The new reference designs are identical to the originals except that the glazing air gap has been increased from 1/4 in. to 1/2 in. and a vector average of the local hourly windspeed was used in the thermal network calculations rather than an assumed average value of 15 m.p.h. Both of these modifications are realistic and enhance the predicted performance of direct gain buildings. A comprehensive set of mass sensitivity calculations has been performed in order to provide information needed to select an appropriate set of parameters for new lightweight direct gain designs for which additional SLR correlations will be developed. Representative results are reported.

  14. Assumptions of the QALY procedure.

    PubMed

    Carr-Hill, R A

    1989-01-01

    The Quality Adjusted Life Year (QALY) has been proposed as a useful index for those managing the provision of health care because it enables the decision-maker to compare the 'value' of different health care programmes and in a way which, potentially at least, reflects social preferences about the appropriate pattern of provision. The index depends on a combination of a measure of morbidity and the risk of mortality. Methodological debate has tended to concentrate on the technicalities of producing a scale of health; and philosophical argument has concentrated on the ethics of interpersonal comparison. There is little recognition of the fragility of the theoretical assumptions underpinning the proposed combination of morbidity and risk of mortality. The context in which the proposed indices are being developed is examined in Section 2. Whilst most working in the field of health measurement eschew over-simplification, it is clear that the application of micro-economics to management is greatly facilitated if a single index can be agreed. The various approaches to combining morbidity and mortality are described in Section 3. The crucial assumptions concern the measurement and valuation of morbidity; the procedures used for scaling morbidity with mortality; and the role of risk. The nature of the valuations involved are examined in Section 4. It seems unlikely that they could ever be widely acceptable; the combination with death and perfect health poses particular problems; and aggregation across individuals compounds the problem. There are also several technical difficulties of scaling and of allowing for risk which have been discussed elsewhere and so are only considered briefly in Section 5 of this paper.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2762872

  15. WTP for a QALY and health states: More money for severer health states?

    PubMed Central

    2013-01-01

    Background In economic evaluation, cost per quality-adjusted life year (QALY) is generally used as an indicator for cost-effectiveness. Although JPY 5 million to 6 million (USD 60, 000 to 75,000) per QALY is frequently referred to as a threshold in Japan, do all QALYs have the same monetary value? Methods To examine the relationship between severity of health status and monetary value of a QALY, we obtained willingness to pay (WTP) values for one additional QALY in eight patterns of health states. We randomly sampled approximately 2,400 respondents from an online panel. To avoid misunderstanding, we randomly allocated respondents to one of 16 questionnaires, with 250 responses expected for each pattern. After respondents were asked whether they wanted to purchase the treatment, double-bounded dichotomous choice method was used to obtain WTP values. Results The results clearly show that the WTP per QALY is higher for worse health states than for better health states. The slope was about JPY −1 million per 0.1 utility score increase. The mean and median WTP values per QALY for 16 health states were JPY 5 million, consistent with our previous survey. For respondents who wanted to purchase the treatment, WTP values were significantly correlated with household income. Conclusion This survey shows that QALY based on the EQ-5D does not necessarily have the same monetary value. The WTP per QALY should range from JPY 2 million (USD 20,000) to JPY 8 million (USD 80,000), corresponding to the severity of health states. PMID:24128004

  16. Global Patterns of QALY and DALY Use in Surgical Cost-Utility Analyses: A Systematic Review

    PubMed Central

    Ramos, Margarita S.; Moscoso, Andrea V.; Vaughn, Patrick; Zogg, Cheryl K.; Caterson, Edward J.

    2016-01-01

    approximately 10 years earlier than DALYs (2000s), the use of both measures continues to increase. Conclusion As global prioritization of surgical interventions gains prominence, it will be important to consider the comparative implications of summary measure use. The results of this study demonstrate significant income- and geographic-based differences in the preferential utilization of the QALY and DALY for surgical cost-effectiveness studies. Such regional variation holds important implications for efforts to interpret and utilize global health policy research. PROSPERO registration number: CRD42015015991 PMID:26862894

  17. QALYs: are they enough? A health economist's perspective.

    PubMed

    Mooney, G

    1989-09-01

    John Rawles's criticism of QALYs are seen as being both imprecise and largely unhelpful. This paper accepts that there are problems in both QALYs themselves and in the current decision-making processes with which they seek to help. The QALY pliers tend to play down the former and the QALY knockers the latter. It is suggested that theories (regret theory and prospect theory) other than expected utility theory, which is normally seen as the basis for QALYs, may provide better approaches to measuring health service outputs. Thus equity, information and decision-making per se are not handled as well in the expected utility QALYs as they could be. Developing better QALYs, with qualifications, is the goal. PMID:2521138

  18. Palliative care for the terminally ill in America: the consideration of QALYs, costs, and ethical issues.

    PubMed

    Yang, Y Tony; Mahon, Margaret M

    2012-11-01

    The drive for cost-effective use of medical interventions has advantages, but can also be challenging in the context of end-of-life palliative treatments. A quality-adjusted life-year (QALY) provides a common currency to assess the extent of the benefits gained from a variety of interventions in terms of health-related quality of life and survival for the patient. However, since it is in the nature of end-of-life palliative care that the benefits it brings to its patients are of short duration, it fares poorly under a policy of QALY-maximization. Nevertheless, we argue that the goals of palliative care and QALY are not incompatible, and optimal integration of palliative care into the calculation of QALY may reveal a mechanism to modify considerations of how optimal quality of life can be achieved, even in the face of terminal illness. The use of QALYs in resource allocation means that palliative care will always compete with alternative uses of the same money. More research should be conducted to evaluate choices between palliative care and more aggressive therapies for the terminally ill. However, current limited data show that investing in palliative care makes more sense not only ethically, but also financially. PMID:22071573

  19. Double jeopardy and the use of QALYs in health care allocation.

    PubMed Central

    Singer, P; McKie, J; Kuhse, H; Richardson, J

    1995-01-01

    The use of the Quality Adjusted Life-Year (QALY) as a measure of the benefit obtained from health care expenditure has been attacked on the ground that it gives a lower value to preserving the lives of people with a permanent disability or illness than to preserving the lives of those who are healthy and not disabled. The reason for this is that the quality of life of those with illness or disability is ranked, on the QALY scale, below that of someone without a disability or illness. Hence we can, other things being equal, gain more QALYs by saving the lives of those without a permanent disability or illness than by saving the lives of those who are disadvantaged in these ways. But to do so puts these disadvantaged people under a kind of double jeopardy. Not only do they suffer from the disability or illness, but because of it, a low priority is given to forms of health care that can preserve their lives. This, so the objection runs, is unjust or unfair. This article assesses this objection to the use of QALYs as a basis for allocating health care resources. It seeks to determine what is sound in the double jeopardy objection, and then to show that the defender of QALYs has an adequate response to it. PMID:7674278

  20. Lifetime QALY prioritarianism in priority setting: quantification of the inherent trade-off

    PubMed Central

    2014-01-01

    Background Multiple principles are relevant in priority setting, two of which are often considered particularly important. According to the greater benefit principle, resources should be directed toward the intervention with the greater health benefit. This principle is intimately linked to the goal of health maximization and standard cost-effectiveness analysis (CEA). According to the worse off principle, resources should be directed toward the intervention benefiting those initially worse off. This principle is often linked to an idea of equity. Together, the two principles accord with prioritarianism; a view which can motivate non-standard CEA. Crucial for the actual application of prioritarianism is the trade-off between the two principles, and this trade-off has received scant attention when the worse off are specified in terms of lifetime health. This paper sheds light on that specific trade-off and on the public support for prioritarianism by providing fresh empirical evidence and by clarifying the close links between the findings and normative theory. Methods A new, self-administered, computer-based questionnaire was used, to which 96 students in Norway responded. How respondents wanted to balance quality-adjusted life years (QALYs) gained against benefiting those with few lifetime QALYs was quantified for a range of different cases. Results Respondents supported both principles and were willing to make trade-offs in a particular way. In the baseline case, the median response valued a QALY 3.3 and 2.5 times more when benefiting someone with lifetime QALYs of 10 and 25 rather than 70. Average responses harbored fundamental disagreements and varied modestly across distributional settings. Conclusion In the specific context of lifetime health, the findings underscore the insufficiency of pure QALY maximization and explicate how people make trade-offs in a way that can help operationalize lifetime prioritarianism and non-standard CEA. Seen through the lens of

  1. A new and more robust test of QALYs.

    PubMed

    Doctor, Jason N; Bleichrodt, Han; Miyamoto, John; Temkin, Nancy R; Dikmen, Sureyya

    2004-03-01

    Previous empirical tests of quality-adjusted life-years (QALYs), the most widely used outcome measure in economic evaluations of health care, generally yielded negative results. These tests were, however, for the most part based on expected utility, which is now widely acknowledged to be descriptively inaccurate. The observed violations might, therefore, have been caused by violations of expected utility. We performed a new test of QALYs, which is valid under expected utility and under the two most influential non-expected utility theories, rank-dependent utility and prospect theory, and found considerable support for the QALY model. Our findings suggest that QALYs may be valid if nonexpected utility formulas are used to compute health state utilities. PMID:15019761

  2. Follow-Up of North Carolina Community College Cooperative Education Graduates: Additional Education and Salary Gains.

    ERIC Educational Resources Information Center

    Johnson, Lillian Riggs

    In this study, North Carolina Community College System (NCCCS) graduates from 1986-1987 were examined 10 years after graduation to see if they had gained additional education and salary. The study's primary purpose was to address the accountability of community college co-op education. Within the study, the term, co-op refers to an educational…

  3. Theoretical foundation of patient v. population preferences in calculating QALYs.

    PubMed

    Gandjour, Afschin

    2010-01-01

    The cost-effectiveness of health care interventions is often evaluated using quality-adjusted life years (QALYs) as a measure of outcome. There is a debate on whether QALYs should use patient preferences as opposed to community preferences. This article shows that patient preferences have a theoretical foundation in preference-utilitarian theory and welfare economics. In contrast, this study found no compelling theoretical basis for community preferences. There is a need for further development of a normative framework to inform the choice of preference source. PMID:20511562

  4. Equity weights in the allocation of health care: the rank-dependent QALY model.

    PubMed

    Bleichrodt, Han; Diecidue, Enrico; Quiggin, John

    2004-01-01

    This paper introduces the rank-dependent quality-adjusted life-years (QALY) model, a new method to aggregate QALYs in economic evaluations of health care. The rank-dependent QALY model permits the formalization of influential concepts of equity in the allocation of health care, such as the fair innings approach, and it includes as special cases many of the social welfare functions that have been proposed in the literature. An important advantage of the rank-dependent QALY model is that it offers a straightforward procedure to estimate equity weights for QALYs. We characterize the rank-dependent QALY model and argue that its central condition has normative appeal.

  5. Interactions of Carbon Gain and Nitrogen Addition in a Temperate Forest

    NASA Astrophysics Data System (ADS)

    Bazzaz, F. A.

    2001-12-01

    In plants, carbon and nitrogen are intimately related. The plant gains carbon using nitrogen because it is a major constituent of both the light reaction (chlorophyll) and dark reaction (Rubisco and PEP carboxylase). The plant also gains more nitrogen by using carbon to grow roots that can forage for nitrogen, especially the less mobile (NH4+). Rising CO2 and increased nitrogen deposition are important elements of global change, both of which may affect ecosystem structure and function. They may cause a particularly large shift in species composition in systems where contrasting groups of species co-occur, e.g. evergreen coniferous and deciduous broad-leaved tree species. We studied the impact of nitrogen deposition in a mixed forest in central Massachusetts (Harvard Forest). We found that the early-successional broad-leaved species, yellow birch (Betula alleghaniensis) and red maple (Acer rubrum), both showed large increases in biomass, while the late successional species sugar maple (Acer saccharum) and all the coniferous species, hemlock (Tsuga canadensis), red spruce (Picea rubens) and white pine (Pinus strobus), only showed slight increases. As a result, when these species wre grown together, there was a decrease in species diversity. There was a significant correlation between species growth rate and the growth enhancement following nitrogen addition. We used SORTIE, a spatially explicit forest model to speculate about the future of this community. In both hemlock and red oak stands, nitrogen deposition led to shift in forest composition towards further dominance of young forests by yellow birch. We conclude that seedling physiological and demographic responses to increased nitrogen availability will scale up to exaggerate successional dynamics in mixed temperate forests in the future

  6. QALYs (Quality Adjusted Life Years): a nurse's view.

    PubMed

    Holmes, C A

    1993-01-01

    Examines the political and ideological significance of measures of quality of life, specifically Quality Adjusted Life Years (QALYs). Briefly reviews recent developments in the debate surrounding the economic and political functions of quality of life measures. The dialectic between conceptions of the quality of life and the implicit realpolitik of socio-economic pressures, ecological conditions, political ethos and cultural norms and expectations, is conceived as a powerful means for the critique of our aspirations concerning health. Argues that existing approaches to assessing quality of life, in denying this dialectic, have jeopardized their potential contribution to the planning, implementation and evaluation of health are policy. Resource allocation challenges us to develop openly ideological strategies and measures.

  7. 36 CFR 51.65 - May the concessioner gain additional leasehold surrender interest by replacing a fixture in which...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... additional leasehold surrender interest by replacing a fixture in which the concessioner has a leasehold... gain additional leasehold surrender interest by replacing a fixture in which the concessioner has a leasehold surrender interest? A concessioner that replaces an existing fixture in which the concessioner...

  8. 36 CFR 51.65 - May the concessioner gain additional leasehold surrender interest by replacing a fixture in which...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... additional leasehold surrender interest by replacing a fixture in which the concessioner has a leasehold... gain additional leasehold surrender interest by replacing a fixture in which the concessioner has a leasehold surrender interest? A concessioner that replaces an existing fixture in which the concessioner...

  9. 36 CFR 51.65 - May the concessioner gain additional leasehold surrender interest by replacing a fixture in which...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... additional leasehold surrender interest by replacing a fixture in which the concessioner has a leasehold... gain additional leasehold surrender interest by replacing a fixture in which the concessioner has a leasehold surrender interest? A concessioner that replaces an existing fixture in which the concessioner...

  10. 36 CFR 51.65 - May the concessioner gain additional leasehold surrender interest by replacing a fixture in which...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... additional leasehold surrender interest by replacing a fixture in which the concessioner has a leasehold... gain additional leasehold surrender interest by replacing a fixture in which the concessioner has a leasehold surrender interest? A concessioner that replaces an existing fixture in which the concessioner...

  11. 36 CFR 51.65 - May the concessioner gain additional leasehold surrender interest by replacing a fixture in which...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... additional leasehold surrender interest by replacing a fixture in which the concessioner has a leasehold... gain additional leasehold surrender interest by replacing a fixture in which the concessioner has a leasehold surrender interest? A concessioner that replaces an existing fixture in which the concessioner...

  12. How you ask is what you get: Framing effects in willingness-to-pay for a QALY.

    PubMed

    Ahlert, Marlies; Breyer, Friedrich; Schwettmann, Lars

    2016-02-01

    In decisions on financing new and innovative health care technologies a central question is how to determine the value citizens place on the gains in health and life expectancy that result from respective medical treatments. We report results of surveys of four representative samples of the German population. In 2010 and 2012, in total about 5000 respondents were asked for their willingness-to-pay (WTP) for either an extension of their life or an improvement in their health corresponding to a gain of one quality-adjusted life year (QALY). Specific changes of the study design allow for ceteris paribus comparisons of different survey versions. While the initial version exactly copied a questionnaire used in the EuroVaQ (European Value of a QALY) project, which was conducted in nine European countries and Palestine, but not in Germany, in other versions the wording and the survey technique were modified. The findings show that the technique of posing the questions plays an important role when respondents are asked to imagine being in hypothetical situations. This clearly refers to the wording of the questions and the survey setting (personal or online interview). But even simple design elements such as putting a yes/no filter in front greatly affect the answers in terms of both the frequency of zero WTP and the distribution of positive amounts. From the different results, we conclude that it is inevitable to conduct studies comprising a broad variety of versions when trying to elicit WTP for a specific type of QALY in order to achieve an array of values combined by insights into the principles of their sensitivity. PMID:26730880

  13. Disentangling WTP per QALY data: different analytical approaches, different answers.

    PubMed

    Gyrd-Hansen, Dorte; Kjaer, Trine

    2012-03-01

    A large random sample of the Danish general population was asked to value health improvements by way of both the time trade-off elicitation technique and willingness-to-pay (WTP) using contingent valuation methods. The data demonstrate a high degree of heterogeneity across respondents in their relative valuations on the two scales. This has implications for data analysis. We show that the estimates of WTP per QALY are highly sensitive to the analytical strategy. For both open-ended and dichotomous choice data we demonstrate that choice of aggregated approach (ratios of means) or disaggregated approach (means of ratios) affects estimates markedly as does the interpretation of the constant term (which allows for disproportionality across the two scales) in the regression analyses. We propose that future research should focus on why some respondents are unwilling to trade on the time trade-off scale, on how to interpret the constant value in the regression analyses, and on how best to capture the heterogeneity in preference structures when applying mixed multinomial logit.

  14. Doula care: nursing students gain additional skills to define their professional practice.

    PubMed

    Jordan, Elizabeth T; Van Zandt, Shirley E; Wright, Erin

    2008-01-01

    Students enter professional nursing with a desire to acquire knowledge, develop skills, and provide nurturing support during life-changing experiences such as childbirth. "Community Perspectives on the Childbearing Process," an elective course at Johns Hopkins University School of Nursing, provides an opportunity to learn and use the skills of physical, emotional, and informational labor support as a "doula." As the first of its kind offered in a school of nursing, this service-learning opportunity offers students the unique opportunity to learn the skills of labor support through an in-depth, hands-on experience. The experience helps students develop a proactive perspective on childbirth and to advocate and support women's choices in labor. Since its inception, more than 379 students have attended 405 births. Students, who become doulas while being educated as nurses, gain new skills, real practice experience, and strong professional standards and identity.

  15. Nitrogen-addition effects on leaf traits and photosynthetic carbon gain of boreal forest understory shrubs.

    PubMed

    Palmroth, Sari; Bach, Lisbet Holm; Nordin, Annika; Palmqvist, Kristin

    2014-06-01

    Boreal coniferous forests are characterized by fairly open canopies where understory vegetation is an important component of ecosystem C and N cycling. We used an ecophysiological approach to study the effects of N additions on uptake and partitioning of C and N in two dominant understory shrubs: deciduous Vaccinium myrtillus in a Picea abies stand and evergreen Vaccinium vitis-idaea in a Pinus sylvestris stand in northern Sweden. N was added to these stands for 16 and 8 years, respectively, at rates of 0, 12.5, and 50 kg N ha(-1) year(-1). N addition at the highest rate increased foliar N and chlorophyll concentrations in both understory species. Canopy cover of P. abies also increased, decreasing light availability and leaf mass per area of V. myrtillus. Among leaves of either shrub, foliar N content did not explain variation in light-saturated CO2 exchange rates. Instead photosynthetic capacity varied with stomatal conductance possibly reflecting plant hydraulic properties and within-site variation in water availability. Moreover, likely due to increased shading under P. abies and due to water limitations in the sandy soil under P. sylvestris, individuals of the two shrubs did not increase their biomass or shift their allocation between above- and belowground parts in response to N additions. Altogether, our results indicate that the understory shrubs in these systems show little response to N additions in terms of photosynthetic physiology or growth and that changes in their performance are mostly associated with responses of the tree canopy.

  16. Additive, dominance, and epistatic loss effects on preweaning weight gain of crossbred beef cattle from different Bos taurus breeds.

    PubMed

    Roso, V M; Schenkel, F S; Miller, S P; Wilton, J W

    2005-08-01

    (Co)variance components, direct and maternal breed additive, dominance, and epistatic loss effects on preweaning weight gain of beef cattle were estimated. Data were from 478,466 animals in Ontario, Canada, from 1986 to 1999, including records of both purebred and crossbred animals from Angus, Blonde d'Aquitaine, Charolais, Gelbvieh, Hereford, Limousin, Maine-Anjou, Salers, Shorthorn, and Simmental breeds. The genetic model included fixed direct and maternal breed additive, dominance, and epistatic loss effects, fixed environmental effects of age of the calf, contemporary group, and age of the dam x sex of the calf, random additive direct and maternal genetic effects, and random maternal permanent environment effects. Estimates of direct and maternal additive genetic, maternal permanent environmental and residual variances, expressed as proportions of the phenotypic variance, were 0.32, 0.20, 0.12, and 0.52, respectively. Correlation between direct and maternal additive genetic effects was -0.63. Breed ranking was similar to previous studies, but estimates showed large SE. The favorable effects of direct and maternal dominance (P < 0.05) on preweaning gain were equivalent to 1.3 and 2.3% of the phenotypic mean of purebred calves, respectively. The same features for direct and maternal epistatic loss effects were -2.2% (P < 0.05) and -0.1% (P > 0.05). The large SE of breed effects were likely due to multicollinearity among predictor variables and deficiencies in the dataset to separate direct and maternal effects and may result in a less reliable ranking of the animals for across breed comparisons. Further research to identify the causes of the instability of estimates of breed additive, dominance, and epistatic loss genetic effects, and application of alternative statistical methods is recommended.

  17. Estimating health state utility values from discrete choice experiments--a QALY space model approach.

    PubMed

    Gu, Yuanyuan; Norman, Richard; Viney, Rosalie

    2014-09-01

    Using discrete choice experiments (DCEs) to estimate health state utility values has become an important alternative to the conventional methods of Time Trade-Off and Standard Gamble. Studies using DCEs have typically used the conditional logit to estimate the underlying utility function. The conditional logit is known for several limitations. In this paper, we propose two types of models based on the mixed logit: one using preference space and the other using quality-adjusted life year (QALY) space, a concept adapted from the willingness-to-pay literature. These methods are applied to a dataset collected using the EQ-5D. The results showcase the advantages of using QALY space and demonstrate that the preferred QALY space model provides lower estimates of the utility values than the conditional logit, with the divergence increasing with worsening health states.

  18. Improving Cross-Sector Comparisons: Going Beyond the Health-Related QALY.

    PubMed

    Brazier, John; Tsuchiya, Aki

    2015-12-01

    The quality-adjusted life-year (QALY) has become a widely used measure of health outcomes for use in informing decision making in health technology assessment. However, there is growing recognition of outcomes beyond health within the health sector and in related sectors such as social care and public health. This paper presents the advantages and disadvantages of ten possible approaches covering extending the health-related QALY and using well-being and monetary-based methods, in order to address the problem of using multiple outcome measures to inform resource allocation within and between sectors. PMID:26324402

  19. Effect of additional optical pumping injection into the ground-state ensemble on the gain and the phase recovery acceleration of quantum-dot semiconductor optical amplifiers

    NASA Astrophysics Data System (ADS)

    Kim, Jungho

    2014-02-01

    The effect of additional optical pumping injection into the ground-state ensemble on the ultrafast gain and the phase recovery dynamics of electrically-driven quantum-dot semiconductor optical amplifiers is numerically investigated by solving 1088 coupled rate equations. The ultrafast gain and the phase recovery responses are calculated with respect to the additional optical pumping power. Increasing the additional optical pumping power can significantly accelerate the ultrafast phase recovery, which cannot be done by increasing the injection current density.

  20. Net gain analysis, an addition to responder analysis--The case of antipsychotic treatment of acute mania.

    PubMed

    Welten, C C M; Koeter, M W J; Wohlfarth, T D; Storosum, J G; van den Brink, W; Gispen-de Wied, C C; Leufkens, H G M; Denys, D A J P

    2015-10-01

    Net Gain Analysis (NGA) is proposed as an alternative to Responders Analysis (RA) as a more comprehensive method to tap clinical relevance of the effect of treatment. NGA is the group difference in responders minus the group difference in deteriorators; while RA is the group difference in responders. We examined the performance of these two methods in a dataset consisting of individual patient data from 10 randomized controlled trials (N = 2666) of five different antipsychotics in patients with acute mania by comparing the rank ordering of the five compounds according to both systems (NGA and RA). The rank order did not differ between the 2 systems but the inferiority of one compound was revealed more evidently by the NGA in comparison to the RA.

  1. Additives

    NASA Technical Reports Server (NTRS)

    Smalheer, C. V.

    1973-01-01

    The chemistry of lubricant additives is discussed to show what the additives are chemically and what functions they perform in the lubrication of various kinds of equipment. Current theories regarding the mode of action of lubricant additives are presented. The additive groups discussed include the following: (1) detergents and dispersants, (2) corrosion inhibitors, (3) antioxidants, (4) viscosity index improvers, (5) pour point depressants, and (6) antifouling agents.

  2. 36 CFR 51.64 - May the concessioner gain additional leasehold surrender interest by undertaking a major...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... additional leasehold surrender interest by undertaking a major rehabilitation or adding to a structure in... a major rehabilitation or adding to a structure in which the concessioner has a leasehold surrender... or adds a new structure (e.g., a new wing to an existing building or an extension of an...

  3. 36 CFR 51.64 - May the concessioner gain additional leasehold surrender interest by undertaking a major...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... additional leasehold surrender interest by undertaking a major rehabilitation or adding to a structure in... a major rehabilitation or adding to a structure in which the concessioner has a leasehold surrender... or adds a new structure (e.g., a new wing to an existing building or an extension of an...

  4. Attentional capture by evaluative stimuli: gain- and loss-connoting colors boost the additional-singleton effect.

    PubMed

    Wentura, Dirk; Müller, Philipp; Rothermund, Klaus

    2014-06-01

    In a valence induction task, one color acquired positive valence by indicating the chance to win money (in the case of fast and correct responses), and a different color acquired negative valence by indicating the danger to lose money (in the case of slow or incorrect responses). In the additional-singleton trials of a visual search task, the task-irrelevant singleton color was either the positive one, the negative one, or one of two neutral colors. We found an additional-singleton effect (i.e., longer RTs with a singleton color than in the no-singleton control condition). This effect was significantly increased for the two valent colors (with no differences between them) relative to the two neutral colors (with no differences between them, either). This result favors the hypothesis that the general relevance of stimuli elicits attentional capture, rather than the negativity bias hypothesis. PMID:24488806

  5. Impact of work-related cancers in Taiwan-Estimation with QALY (quality-adjusted life year) and healthcare costs.

    PubMed

    Lee, Lukas Jyuhn-Hsiarn; Lin, Cheng-Kuan; Hung, Mei-Chuan; Wang, Jung-Der

    2016-12-01

    This study estimates the annual numbers of eight work-related cancers, total losses of quality-adjusted life years (QALYs), and lifetime healthcare expenditures that possibly could be saved by improving occupational health in Taiwan. Three databases were interlinked: the Taiwan Cancer Registry, the National Mortality Registry, and the National Health Insurance Research Database. Annual numbers of work-related cancers were estimated based on attributable fractions (AFs) abstracted from a literature review. The survival functions for eight cancers were estimated and extrapolated to lifetime using a semi-parametric method. A convenience sample of 8846 measurements of patients' quality of life with EQ-5D was collected for utility values and multiplied by survival functions to estimate quality-adjusted life expectancies (QALEs). The loss-of-QALE was obtained by subtracting the QALE of cancer from age- and sex-matched referents simulated from national vital statistics. The lifetime healthcare expenditures were estimated by multiplying the survival probability with mean monthly costs paid by the National Health Insurance for cancer diagnosis and treatment and summing this for the expected lifetime. A total of 3010 males and 726 females with eight work-related cancers were estimated in 2010. Among them, lung cancer ranked first in terms of QALY loss, with an annual total loss-of-QALE of 28,463 QALYs and total lifetime healthcare expenditures of US$36.6 million. Successful prevention of eight work-related cancers would not only avoid the occurrence of 3736 cases of cancer, but would also save more than US$70 million in healthcare costs and 46,750 QALYs for the Taiwan society in 2010. PMID:27413666

  6. Impact of work-related cancers in Taiwan-Estimation with QALY (quality-adjusted life year) and healthcare costs.

    PubMed

    Lee, Lukas Jyuhn-Hsiarn; Lin, Cheng-Kuan; Hung, Mei-Chuan; Wang, Jung-Der

    2016-12-01

    This study estimates the annual numbers of eight work-related cancers, total losses of quality-adjusted life years (QALYs), and lifetime healthcare expenditures that possibly could be saved by improving occupational health in Taiwan. Three databases were interlinked: the Taiwan Cancer Registry, the National Mortality Registry, and the National Health Insurance Research Database. Annual numbers of work-related cancers were estimated based on attributable fractions (AFs) abstracted from a literature review. The survival functions for eight cancers were estimated and extrapolated to lifetime using a semi-parametric method. A convenience sample of 8846 measurements of patients' quality of life with EQ-5D was collected for utility values and multiplied by survival functions to estimate quality-adjusted life expectancies (QALEs). The loss-of-QALE was obtained by subtracting the QALE of cancer from age- and sex-matched referents simulated from national vital statistics. The lifetime healthcare expenditures were estimated by multiplying the survival probability with mean monthly costs paid by the National Health Insurance for cancer diagnosis and treatment and summing this for the expected lifetime. A total of 3010 males and 726 females with eight work-related cancers were estimated in 2010. Among them, lung cancer ranked first in terms of QALY loss, with an annual total loss-of-QALE of 28,463 QALYs and total lifetime healthcare expenditures of US$36.6 million. Successful prevention of eight work-related cancers would not only avoid the occurrence of 3736 cases of cancer, but would also save more than US$70 million in healthcare costs and 46,750 QALYs for the Taiwan society in 2010.

  7. Searchers vs surveyors in estimating the monetary value of a QALY: resolving a nasty dilemma for NICE.

    PubMed

    Baker, Rachel; Chilton, Sue; Donaldson, Cam; Jones-Lee, Michael; Lancsar, Emily; Mason, Helen; Metcalf, Hugh; Pennington, Mark; Wildman, John

    2011-10-01

    Recently, for many health economics researchers, empirical estimation of the monetary valuation of a quality-adjusted life year (QALY) has become an important endeavour. Different philosophical and practical approaches to this have emerged. On the one hand, there is a view that, with health-care budgets set centrally, decision-making bodies within the system can iterate, from observation of a series of previous decisions, towards the value of a QALY, thus searching for such a value. Alternatively, and more consistent with the approach taken in other public sectors, individual members of the public are surveyed with the aim of directly eliciting a preference-based - also known as a willingness-to-pay-based (WTP-based) - value of a QALY. While the former is based on supply-side factors and the latter on demand, both in fact suffer from informational deficiencies. Sole reliance on either would necessitate an acceptance or accommodation of chronic inefficiencies in health-care resource allocation. On the basis of this observation, this paper makes the case that in order to approach optimal decision making in health-care provision, a framework incorporating and thus, to a degree, reconciling these two approaches is to be preferred.

  8. Searchers vs surveyors in estimating the monetary value of a QALY: resolving a nasty dilemma for NICE.

    PubMed

    Baker, Rachel; Chilton, Sue; Donaldson, Cam; Jones-Lee, Michael; Lancsar, Emily; Mason, Helen; Metcalf, Hugh; Pennington, Mark; Wildman, John

    2011-10-01

    Recently, for many health economics researchers, empirical estimation of the monetary valuation of a quality-adjusted life year (QALY) has become an important endeavour. Different philosophical and practical approaches to this have emerged. On the one hand, there is a view that, with health-care budgets set centrally, decision-making bodies within the system can iterate, from observation of a series of previous decisions, towards the value of a QALY, thus searching for such a value. Alternatively, and more consistent with the approach taken in other public sectors, individual members of the public are surveyed with the aim of directly eliciting a preference-based - also known as a willingness-to-pay-based (WTP-based) - value of a QALY. While the former is based on supply-side factors and the latter on demand, both in fact suffer from informational deficiencies. Sole reliance on either would necessitate an acceptance or accommodation of chronic inefficiencies in health-care resource allocation. On the basis of this observation, this paper makes the case that in order to approach optimal decision making in health-care provision, a framework incorporating and thus, to a degree, reconciling these two approaches is to be preferred. PMID:21854688

  9. Challenges in health state valuation in paediatric economic evaluation: are QALYs contraindicated?

    PubMed

    Ungar, Wendy J

    2011-08-01

    With the growth in the use of health economic evaluation to inform healthcare resource allocation decisions, the challenges in applying standard methods to child health have become apparent. A unique limitation is the paucity of child-specific preference-based measures. A single, valid, preference-based measure of utility that can be used in children of all ages does not exist. Thus, the ability to derive a QALY for use in cost-utility analysis (CUA) is compromised. This paper presents and discusses existing and novel options for deriving utilities for paediatric health states for use in CUAs. While a direct elicitation may be preferred, a child's ability to complete a standard gamble or time trade-off task is hampered by cognitive and age limitations. The abstract notions contained in indirect instruments such as the EQ-5D and Health Utilities Index may also pose challenges for young children. Novel approaches to overcome these challenges include the development of age-appropriate instruments such as the EQ-5D-Y, the development of new child-specific utility instruments such as the Child Health Utility-9D and the re-calibration of existing adult instruments to derive preference weights for health states from children themselves. For children aged <6 years, researchers have little choice but to use a proxy reporter such as parents. While parents may be reliable reporters for physical activity limitations and externally manifest symptoms, their ability to accurately report on subjective outcomes such as emotion is questionable. Catalogues of utility weights for a range of conditions are increasingly becoming available but retain many of the same limitations as valuing health states from children or from proxies. Given the dynamic relationship in quality of life (QOL) between family members when a child is ill, it seems appropriate to consider a 'family perspective' rather than an individual perspective in child health state valuation. In a collective approach

  10. Modeling techniques for gaining additional urban space

    NASA Astrophysics Data System (ADS)

    Thunig, Holger; Naumann, Simone; Siegmund, Alexander

    2009-09-01

    One of the major accompaniments of the globalization is the rapid growing of urban areas. Urban sprawl is the main environmental problem affecting those cities across different characteristics and continents. Various reasons for the increase in urban sprawl in the last 10 to 30 years have been proposed [1], and often depend on the socio-economic situation of cities. The quantitative reduction and the sustainable handling of land should be performed by inner urban development instead of expanding urban regions. Following the principal "spare the urban fringe, develop the inner suburbs first" requires differentiated tools allowing for quantitative and qualitative appraisals of current building potentials. Using spatial high resolution remote sensing data within an object-based approach enables the detection of potential areas while GIS-data provides information for the quantitative valuation. This paper presents techniques for modeling urban environment and opportunities of utilization of the retrieved information for urban planners and their special needs.

  11. PPD-QALY-an index for cost-effectiveness in orthopedics: providing essential information to both physicians and health care policy makers for appropriate allocation of medical resources.

    PubMed

    Dougherty, Christopher P; Howard, Timothy

    2013-09-01

    Because of the increasing health care costs and the need for proper allocation of resources, it is important to ensure the best use of health benefits for sick and injured people of the population. An index or indicator is needed to help us quantify what is being spent so that comparisons with other options can be implemented. Cost-effective analysis seems to be well suited to provide this essential information to health care policy makers and those charged with distributing disability funds so that the proper allocation of resources can be achieved. There is currently no such index to show whether the benefits paid out are the most cost-effective. By comparing the quality-adjusted life year (QALY) of a treatment method to the disability an individual would experience, on the basis of lost wages as measure of disability, we provide decision makers more information for the basis of cost allocation in health care. To accomplish this, we describe a new term, the PPD-QALY (permanent partial disability-quality of life year). This term was developed to establish an index to which musculoskeletal care can be compared, to evaluate the cost-effectiveness of a treatment on the basis of the monetary value of the disability. This term serves to standardize the monetary value of an injury. Cost-effective analysis in arthroscopic surgery may prove to be a valuable asset in this role and to provide decision makers the information needed to determine the societal benefit from new arthroscopic procedures as they are developed and implemented. PMID:23924750

  12. PPD-QALY-an index for cost-effectiveness in orthopedics: providing essential information to both physicians and health care policy makers for appropriate allocation of medical resources.

    PubMed

    Dougherty, Christopher P; Howard, Timothy

    2013-09-01

    Because of the increasing health care costs and the need for proper allocation of resources, it is important to ensure the best use of health benefits for sick and injured people of the population. An index or indicator is needed to help us quantify what is being spent so that comparisons with other options can be implemented. Cost-effective analysis seems to be well suited to provide this essential information to health care policy makers and those charged with distributing disability funds so that the proper allocation of resources can be achieved. There is currently no such index to show whether the benefits paid out are the most cost-effective. By comparing the quality-adjusted life year (QALY) of a treatment method to the disability an individual would experience, on the basis of lost wages as measure of disability, we provide decision makers more information for the basis of cost allocation in health care. To accomplish this, we describe a new term, the PPD-QALY (permanent partial disability-quality of life year). This term was developed to establish an index to which musculoskeletal care can be compared, to evaluate the cost-effectiveness of a treatment on the basis of the monetary value of the disability. This term serves to standardize the monetary value of an injury. Cost-effective analysis in arthroscopic surgery may prove to be a valuable asset in this role and to provide decision makers the information needed to determine the societal benefit from new arthroscopic procedures as they are developed and implemented.

  13. Weight gain - unintentional

    MedlinePlus

    ... as much as 25 to 30 pounds. This weight gain is not simply due to eating more. ... or a dietitian about how to make a healthy eating plan and set ... be causing the weight gain without talking with your provider.

  14. Adaptive allocation of attentional gain

    PubMed Central

    Scolari, Miranda; Serences, John T.

    2009-01-01

    Humans are adept at distinguishing between stimuli that are very similar, an ability that is particularly crucial when the outcome is of serious consequence (e.g. for a surgeon or air traffic controller). Traditionally, selective attention was thought to facilitate perception by increasing the gain of sensory neurons tuned to the defining features of a behaviorally relevant object (e.g. color, orientation, etc.). In contrast, recent mathematical models counter-intuitively suggest that in many cases attentional gain should be applied to neurons that are tuned away from relevant features, especially when discriminating highly similar stimuli. Here we used psychophysical methods to critically evaluate these ‘ideal observer’ models. The data demonstrate that attention enhances the gain of the most informative sensory neurons, even when these neurons are tuned away from the behaviorally relevant target feature. Moreover, the degree to which an individual adopted optimal attentional gain settings by the end of testing predicted success rates on a difficult visual discrimination task, as well as the amount of task improvement that occurred across repeated testing sessions (learning). Contrary to most traditional accounts, these observations suggest that the primary function of attentional gain is not simply to enhance the representation of target features, but to optimize performance on the current perceptual task. Additionally, individual differences in gain suggest that the operating characteristics of low-level attentional phenomena are not stable trait-like attributes and that variability in how attention is deployed may play an important role in determining perceptual abilities. PMID:19776279

  15. Gain weighted eigenspace assignment

    NASA Technical Reports Server (NTRS)

    Davidson, John B.; Andrisani, Dominick, II

    1994-01-01

    This report presents the development of the gain weighted eigenspace assignment methodology. This provides a designer with a systematic methodology for trading off eigenvector placement versus gain magnitudes, while still maintaining desired closed-loop eigenvalue locations. This is accomplished by forming a cost function composed of a scalar measure of error between desired and achievable eigenvectors and a scalar measure of gain magnitude, determining analytical expressions for the gradients, and solving for the optimal solution by numerical iteration. For this development the scalar measure of gain magnitude is chosen to be a weighted sum of the squares of all the individual elements of the feedback gain matrix. An example is presented to demonstrate the method. In this example, solutions yielding achievable eigenvectors close to the desired eigenvectors are obtained with significant reductions in gain magnitude compared to a solution obtained using a previously developed eigenspace (eigenstructure) assignment method.

  16. Plasmonics: Loss and gain

    NASA Astrophysics Data System (ADS)

    Oulton, Rupert F.

    2012-04-01

    Providing sufficient gain to overcome loss remains a fundamental challenge for light amplification in miniaturized plasmonic devices. Ongoing research gives hope for a cautious but optimistic outlook.

  17. Invention and Gain Analysis.

    ERIC Educational Resources Information Center

    Weber, Robert J.; Dixon, Stacey

    1989-01-01

    Gain analysis is applied to the invention of the sewing needle as well as different sewing implements and modes of sewing. The analysis includes a two-subject experiment. To validate the generality of gain heuristics and underlying switching processes, the invention of the assembly line is also analyzed. (TJH)

  18. Preventing Weight Gain

    MedlinePlus

    ... If this is the case, preventing further weight gain is a worthy goal. As people age, their body composition gradually shifts — the proportion of muscle decreases and the proportion of fat increases. This ...

  19. Receiver Gain Modulation Circuit

    NASA Technical Reports Server (NTRS)

    Jones, Hollis; Racette, Paul; Walker, David; Gu, Dazhen

    2011-01-01

    A receiver gain modulation circuit (RGMC) was developed that modulates the power gain of the output of a radiometer receiver with a test signal. As the radiometer receiver switches between calibration noise references, the test signal is mixed with the calibrated noise and thus produces an ensemble set of measurements from which ensemble statistical analysis can be used to extract statistical information about the test signal. The RGMC is an enabling technology of the ensemble detector. As a key component for achieving ensemble detection and analysis, the RGMC has broad aeronautical and space applications. The RGMC can be used to test and develop new calibration algorithms, for example, to detect gain anomalies, and/or correct for slow drifts that affect climate-quality measurements over an accelerated time scale. A generalized approach to analyzing radiometer system designs yields a mathematical treatment of noise reference measurements in calibration algorithms. By treating the measurements from the different noise references as ensemble samples of the receiver state, i.e. receiver gain, a quantitative description of the non-stationary properties of the underlying receiver fluctuations can be derived. Excellent agreement has been obtained between model calculations and radiometric measurements. The mathematical formulation is equivalent to modulating the gain of a stable receiver with an externally generated signal and is the basis for ensemble detection and analysis (EDA). The concept of generating ensemble data sets using an ensemble detector is similar to the ensemble data sets generated as part of ensemble empirical mode decomposition (EEMD) with exception of a key distinguishing factor. EEMD adds noise to the signal under study whereas EDA mixes the signal with calibrated noise. It is mixing with calibrated noise that permits the measurement of temporal-functional variability of uncertainty in the underlying process. The RGMC permits the evaluation of EDA by

  20. Amoco technique gains support

    SciTech Connect

    1995-10-01

    Amoco Corp.`s low-cost horizontal drilling technique and equipment are gaining acceptance in the oilpatch after five years of design and fine-tuning work. The system is purely mechanical, and it`s designed to operate with a workover rig instead of a drilling rig. It`s engineered to drill short-radius horizontal wells with lateral sup to 1,000 feet, so far.

  1. Helicopter high gain control

    NASA Technical Reports Server (NTRS)

    Cunningham, T. B.; Nunn, E. C.

    1979-01-01

    High gain control is explored through a design study of the CH-47B helicopter. The plans are designed to obtain the maximum bandwidth possible given the hardware constraints. Controls are designed with modal control theory to specific bandwidths and closed loop mode shapes. Comparisons are made to an earlier complementary filter approach. Bandwidth improvement by removal of limitations is explored in order to establish hardware and mechanization options. Improvements in the pitch axis control system and in the rate gyro sensor noise characteristics in all axes are discussed. The use of rotor state feedback is assessed.

  2. Collapsible high gain antenna

    NASA Technical Reports Server (NTRS)

    Cribb, H. E. (Inventor)

    1973-01-01

    A lightweight small high gain antenna which is capable of being packaged in a collapsed form and automatically expanded when in use is described. The antenna includes a cylindrical housing having a rod with a piston adjacent to one end extending through it. Attached to the outer end of the rod in a normally collapsed state is a helical wire coil. When the gas producing means is activated the piston and rod are shifted outwardly to expand the wire coil. A latch is provided for holding the helical coil in the expanded position.

  3. Smoking Cessation and Weight Gain.

    ERIC Educational Resources Information Center

    Hall, Sharon M.; And Others

    1986-01-01

    Investigated determinants of weight gain after quitting smoking in two smoking treatment outcome studies. Results indicated abstinence resulted in weight gain, and postquitting weight gain was predicted by pretreatment tobacco use, a history of weight problems, and eating patterns. Relapse to smoking did not follow weight gain. (Author/BL)

  4. Managing price, gaining profit.

    PubMed

    Marn, M V; Rosiello, R L

    1992-01-01

    The fastest and most effective way for a company to realize maximum profit is to get its pricing right. The right price can boost profit faster than increasing volume will; the wrong price can shrink it just as quickly. Yet many otherwise tough-minded managers miss out on significant profits because they shy away from pricing decisions for fear that they will alienate their customers. Worse, if management isn't controlling its pricing policies, there's a good chance that the company's clients are manipulating them to their own advantage. McKinsey & Company's Michael Marn and Robert Rosiello show managers how to gain control of the pricing puzzle and capture untapped profit potential by using two basic concepts: the pocket price waterfall and the pocket price band. The pocket price waterfall reveals how price erodes between a company's invoice figure and the actual amount paid by the customer--the transaction price. It tracks the volume purchase discounts, early payment bonuses, and frequent customer incentives that squeeze a company's profits. The pocket price band plots the range of pocket prices over which any given unit volume of a single product sells. Wide price bands are commonplace: some manufacturers' transaction prices for a given product range 60%; one fastener supplier's price band ranged up to 500%. Managers who study their pocket price waterfalls and bands can identify unnecessary discounting at the transaction level, low-performance accounts, and misplaced marketing efforts. The problems, once identified, are typically easy and inexpensive to remedy. PMID:10121318

  5. Acting to gain information

    NASA Technical Reports Server (NTRS)

    Rosenchein, Stanley J.; Burns, J. Brian; Chapman, David; Kaelbling, Leslie P.; Kahn, Philip; Nishihara, H. Keith; Turk, Matthew

    1993-01-01

    This report is concerned with agents that act to gain information. In previous work, we developed agent models combining qualitative modeling with real-time control. That work, however, focused primarily on actions that affect physical states of the environment. The current study extends that work by explicitly considering problems of active information-gathering and by exploring specialized aspects of information-gathering in computational perception, learning, and language. In our theoretical investigations, we analyzed agents into their perceptual and action components and identified these with elements of a state-machine model of control. The mathematical properties of each was developed in isolation and interactions were then studied. We considered the complexity dimension and the uncertainty dimension and related these to intelligent-agent design issues. We also explored active information gathering in visual processing. Working within the active vision paradigm, we developed a concept of 'minimal meaningful measurements' suitable for demand-driven vision. We then developed and tested an architecture for ongoing recognition and interpretation of visual information. In the area of information gathering through learning, we explored techniques for coping with combinatorial complexity. We also explored information gathering through explicit linguistic action by considering the nature of conversational rules, coordination, and situated communication behavior.

  6. Managing price, gaining profit.

    PubMed

    Marn, M V; Rosiello, R L

    1992-01-01

    The fastest and most effective way for a company to realize maximum profit is to get its pricing right. The right price can boost profit faster than increasing volume will; the wrong price can shrink it just as quickly. Yet many otherwise tough-minded managers miss out on significant profits because they shy away from pricing decisions for fear that they will alienate their customers. Worse, if management isn't controlling its pricing policies, there's a good chance that the company's clients are manipulating them to their own advantage. McKinsey & Company's Michael Marn and Robert Rosiello show managers how to gain control of the pricing puzzle and capture untapped profit potential by using two basic concepts: the pocket price waterfall and the pocket price band. The pocket price waterfall reveals how price erodes between a company's invoice figure and the actual amount paid by the customer--the transaction price. It tracks the volume purchase discounts, early payment bonuses, and frequent customer incentives that squeeze a company's profits. The pocket price band plots the range of pocket prices over which any given unit volume of a single product sells. Wide price bands are commonplace: some manufacturers' transaction prices for a given product range 60%; one fastener supplier's price band ranged up to 500%. Managers who study their pocket price waterfalls and bands can identify unnecessary discounting at the transaction level, low-performance accounts, and misplaced marketing efforts. The problems, once identified, are typically easy and inexpensive to remedy.

  7. On Comparing Transition Rate Gains.

    ERIC Educational Resources Information Center

    Reuterberg, Sven-Eric

    This report is about the problem of making transition or enrollment rate gains comparable. It is shown that measures based on the proportions themselves, i.e. the difference between proportions, the proportion ratio and the residual gain ratio do not make the gains comparable. Instead a non-linear transformation has to be done. Two such…

  8. Airflow models gaining clout

    SciTech Connect

    Post, N.M.

    1994-10-10

    Move over, mock-ups. So long, smoke bombs. Take a walk, wind tunnels. Computational fluid dynamics, a spaceage simulation technique, is gaining velocity in the building community. And the design of inner spaces may never be the same. CFD is an equation-intensive computer modeling method that can simulate transient and steady-state airflow patterns and temperature gradients, indoors or out. CFD is used to downsize heating, ventilating and air conditioning systems, locate air outlets, and in general, create spaces that offer creature comfort, provide quality air and use less energy. The method is good for new construction, retrofits and forensic work, for example to investigate a building fire or a contaminant. In a room, CFD helps engineers consider, over a period of time, the combined impacts of ventilation, size, shape, contents, weather, even fenestration. For its first decade or two, CFD stayed the near-exclusive domain of aerospace, defense and electronics. With few exceptions, the building community could not afford the supercomputers that were needed to run the tens of thousands of equations involved. However, in the past few years, thanks to the increasing power and decreasing cost of computers, CFD simulation became practical. Curtain wall designers are even using it, though not without some controversy. Indoor air quality specialists, smoke and fire-spread researchers, laboratory designers, energy engineers, code writers, architects, and plant and building engineers are uncharacteristically upbeat about the tool. {open_quotes}CFD modeling is so many light years ahead of design tools that exist,{close_quotes} says Mariano Rodriguez, director of research and development for architect The Hillier Group, Princeton, N.J. {open_quotes}It`s the next step up from a wind tunnel test, and you don`t need a $300,000 wind tunnel.{close_quotes}

  9. Assessment of cost of innovation versus the value of health gains associated with treatment of chronic hepatitis C in the United States

    PubMed Central

    Younossi, Zobair M.; Park, Haesuk; Dieterich, Douglas; Saab, Sammy; Ahmed, Aijaz; Gordon, Stuart C.

    2016-01-01

    Abstract Background: New direct-acting antiviral (DAA) therapy has dramatically increased cure rates for patients infected with hepatitis C virus (HCV), but has also substantially raised treatment costs. Aim: The aim of this analysis was to evaluate the therapeutic benefit and net costs (i.e. efficiency frontier) and the quality-adjusted cost of care associated with the evolution of treatment regimens for patients with HCV genotype 1 in the United States. Design: A decision-analytic Markov model. Data source: Published literature and clinical trial data. Time horizon: Life Time. Perspective: Third-party payer. Intervention: This study compared four approved regimens in treatment-naïve genotype 1 chronic hepatitis C patients, including pegylated interferon and ribavirin (PR), first generation triple therapy (boceprevir + PR and telaprevir + PR), second generation triple therapy (sofosbuvir + PR and simeprevir + PR) and all-oral DAA regimens (ledipasvir/sofosbuvir and ombitasvir + paritaprevir/ritonavir + dasabuvir ± ribavirin). Outcome measure: Quality-adjusted cost of care (QACC). QACC was defined as the increase in treatment cost minus the increase in the patient's quality-adjusted life years (QALYs) when valued at $50,000 per QALY. Results: All-oral therapy improved the average sustained virologic response (SVR) rate to 96%, thereby offsetting the high drug acquisition cost of $85,714, which resulted in the highest benefit based on the efficiency frontier. Furthermore, while oral therapies increased HCV drug costs by $48,350, associated QALY gains decreased quality-adjusted cost of care by $14,120 compared to dual therapy. When the value of a QALY was varied from $100,000 to $300,000, the quality adjusted cost of care compared to dual therapy ranged from − $21,234 to − $107,861, − $89,007 to − $293,130, − $176,280 to − $500,599 for first generation triple, second generation triple, and all-oral therapies

  10. Food additives

    PubMed Central

    Spencer, Michael

    1974-01-01

    Food additives are discussed from the food technology point of view. The reasons for their use are summarized: (1) to protect food from chemical and microbiological attack; (2) to even out seasonal supplies; (3) to improve their eating quality; (4) to improve their nutritional value. The various types of food additives are considered, e.g. colours, flavours, emulsifiers, bread and flour additives, preservatives, and nutritional additives. The paper concludes with consideration of those circumstances in which the use of additives is (a) justified and (b) unjustified. PMID:4467857

  11. Image formation using stimulated raman scattering gain

    NASA Astrophysics Data System (ADS)

    Bespalov, V. G.; Makarov, E. A.; Stasel'ko, D. I.

    2016-07-01

    Theoretical analysis of the spatial, noise, and energy characteristics of an amplifier has been performed in the mode of spectral and time selection using subnanosecond stimulated Raman Scattering gain of weak echo signals in crystalline active media that are known for high (up to 10-1 cm/MW) gain coefficients. The possibility to reach high gain values has been demonstrated for weak signals from objects at acceptable angular sizes of the field of vision of an amplifier. To provide a signal-to-noise ratio that exceeds unity over the entire field of vision, the number of photons at the input to an amplifier that is required has to exceed the number of its resolution elements. Accurate determination of the possibilities of recording of weak echo signals and quality of images of targets that are obtained using amplifiers under stimulated Raman Scattering requires additional special experiments.

  12. Optimum Reliability of Gain Scores.

    ERIC Educational Resources Information Center

    Sharma, K. K.; Gupta, J. K.

    1986-01-01

    This paper gives a mathematical treatment to findings of Zimmerman and Williams and establishes a minimum reliability for gain scores when the pretest and posttest have equal reliabilities and equal standard deviations. It discusses the behavior of the reliability of gain scores in terms of variations in other test parameters. (Author/LMO)

  13. Computer algorithm for coding gain

    NASA Technical Reports Server (NTRS)

    Dodd, E. E.

    1974-01-01

    Development of a computer algorithm for coding gain for use in an automated communications link design system. Using an empirical formula which defines coding gain as used in space communications engineering, an algorithm is constructed on the basis of available performance data for nonsystematic convolutional encoding with soft-decision (eight-level) Viterbi decoding.

  14. Major oil, gas reserve additions reported

    SciTech Connect

    1997-03-10

    Several large, internationally active, US-based companies have recently reported sizable gains in oil and gas reserves in 1996. The biggest reserves addition in absolute terms reported to date belongs to Exxon Corp. However, Amoco Corp. scored the largest percentage gain. The paper discusses gains reported by Exxon, Amoco, ARCO, Phillips, and Oryx.

  15. Gaining approval for clinical research.

    PubMed

    Cobb, Vanessa; Srinivasan, Neil; Lambiase, Pier

    2016-07-01

    Set-up and delivery of a clinical research project can be complicated and difficult. This article introduces the regulatory processes involved in gaining approval for clinical research and discusses the obstacles that may be encountered. PMID:27388381

  16. Developmental gains in visuospatial memory predict gains in mathematics achievement.

    PubMed

    Li, Yaoran; Geary, David C

    2013-01-01

    Visuospatial competencies are related to performance in mathematical domains in adulthood, but are not consistently related to mathematics achievement in children. We confirmed the latter for first graders and demonstrated that children who show above average first-to-fifth grade gains in visuospatial memory have an advantage over other children in mathematics. The study involved the assessment of the mathematics and reading achievement of 177 children in kindergarten to fifth grade, inclusive, and their working memory capacity and processing speed in first and fifth grade. Intelligence was assessed in first grade and their second to fourth grade teachers reported on their in-class attentive behavior. Developmental gains in visuospatial memory span (d = 2.4) were larger than gains in the capacity of the central executive (d = 1.6) that in turn were larger than gains in phonological memory span (d = 1.1). First to fifth grade gains in visuospatial memory and in speed of numeral processing predicted end of fifth grade mathematics achievement, as did first grade central executive scores, intelligence, and in-class attentive behavior. The results suggest there are important individual differences in the rate of growth of visuospatial memory during childhood and that these differences become increasingly important for mathematics learning. PMID:23936154

  17. Developmental Gains in Visuospatial Memory Predict Gains in Mathematics Achievement

    PubMed Central

    Li, Yaoran; Geary, David C.

    2013-01-01

    Visuospatial competencies are related to performance in mathematical domains in adulthood, but are not consistently related to mathematics achievement in children. We confirmed the latter for first graders and demonstrated that children who show above average first-to-fifth grade gains in visuospatial memory have an advantage over other children in mathematics. The study involved the assessment of the mathematics and reading achievement of 177 children in kindergarten to fifth grade, inclusive, and their working memory capacity and processing speed in first and fifth grade. Intelligence was assessed in first grade and their second to fourth grade teachers reported on their in-class attentive behavior. Developmental gains in visuospatial memory span (d = 2.4) were larger than gains in the capacity of the central executive (d = 1.6) that in turn were larger than gains in phonological memory span (d = 1.1). First to fifth grade gains in visuospatial memory and in speed of numeral processing predicted end of fifth grade mathematics achievement, as did first grade central executive scores, intelligence, and in-class attentive behavior. The results suggest there are important individual differences in the rate of growth of visuospatial memory during childhood and that these differences become increasingly important for mathematics learning. PMID:23936154

  18. Developmental gains in visuospatial memory predict gains in mathematics achievement.

    PubMed

    Li, Yaoran; Geary, David C

    2013-01-01

    Visuospatial competencies are related to performance in mathematical domains in adulthood, but are not consistently related to mathematics achievement in children. We confirmed the latter for first graders and demonstrated that children who show above average first-to-fifth grade gains in visuospatial memory have an advantage over other children in mathematics. The study involved the assessment of the mathematics and reading achievement of 177 children in kindergarten to fifth grade, inclusive, and their working memory capacity and processing speed in first and fifth grade. Intelligence was assessed in first grade and their second to fourth grade teachers reported on their in-class attentive behavior. Developmental gains in visuospatial memory span (d = 2.4) were larger than gains in the capacity of the central executive (d = 1.6) that in turn were larger than gains in phonological memory span (d = 1.1). First to fifth grade gains in visuospatial memory and in speed of numeral processing predicted end of fifth grade mathematics achievement, as did first grade central executive scores, intelligence, and in-class attentive behavior. The results suggest there are important individual differences in the rate of growth of visuospatial memory during childhood and that these differences become increasingly important for mathematics learning.

  19. Phosphazene additives

    DOEpatents

    Harrup, Mason K; Rollins, Harry W

    2013-11-26

    An additive comprising a phosphazene compound that has at least two reactive functional groups and at least one capping functional group bonded to phosphorus atoms of the phosphazene compound. One of the at least two reactive functional groups is configured to react with cellulose and the other of the at least two reactive functional groups is configured to react with a resin, such as an amine resin of a polycarboxylic acid resin. The at least one capping functional group is selected from the group consisting of a short chain ether group, an alkoxy group, or an aryloxy group. Also disclosed are an additive-resin admixture, a method of treating a wood product, and a wood product.

  20. Potlining Additives

    SciTech Connect

    Rudolf Keller

    2004-08-10

    In this project, a concept to improve the performance of aluminum production cells by introducing potlining additives was examined and tested. Boron oxide was added to cathode blocks, and titanium was dissolved in the metal pool; this resulted in the formation of titanium diboride and caused the molten aluminum to wet the carbonaceous cathode surface. Such wetting reportedly leads to operational improvements and extended cell life. In addition, boron oxide suppresses cyanide formation. This final report presents and discusses the results of this project. Substantial economic benefits for the practical implementation of the technology are projected, especially for modern cells with graphitized blocks. For example, with an energy savings of about 5% and an increase in pot life from 1500 to 2500 days, a cost savings of $ 0.023 per pound of aluminum produced is projected for a 200 kA pot.

  1. Gainful Activity and Intimate Partner Aggression in Emerging Adulthood*

    PubMed Central

    Alvira-Hammond, Marta; Longmore, Monica A.; Manning, Wendy D.; Giordano, Peggy C.

    2014-01-01

    Although intimate partner aggression crosses social class boundaries, education and income are important predictors. Yet given that emerging adulthood is a transitional period, completed education and employment, as single measures, are not ideal indicators of socioeconomic status for young people. We examined associations between self-reports of gainful activity, defined as enrollment in school or full-time employment, and intimate partner aggression among young adults in dating, cohabiting, or married relationships (N=648). Both men and women's participation in gainful activity was negatively associated with aggression. We found that when neither partner was gainfully active, individuals reported higher frequency of physical aggression. In cases of gainful activity asymmetry, the gender of the gainfully active partner did not predict intimate partner aggression. Additionally, we found no evidence that the association between gainful activity and frequency of intimate partner aggression differed by union type. PMID:25309829

  2. High current gain transistor laser.

    PubMed

    Liang, Song; Qiao, Lijun; Zhu, Hongliang; Wang, Wei

    2016-06-10

    A transistor laser (TL), having the structure of a transistor with multi-quantum wells near its base region, bridges the functionality gap between lasers and transistors. However, light emission is produced at the expense of current gain for all the TLs reported up to now, leading to a very low current gain. We propose a novel design of TLs, which have an n-doped InP layer inserted in the emitter ridge. Numerical studies show that a current flow aperture for only holes can be formed in the center of the emitter ridge. As a result, the common emitter current gain can be as large as 143.3, which is over 15 times larger than that of a TL without the aperture. Besides, the effects of nonradiative recombination defects can be reduced greatly because the flow of holes is confined in the center region of the emitter ridge.

  3. Commutated automatic gain control system

    NASA Technical Reports Server (NTRS)

    Yost, S. R.

    1981-01-01

    A commutated automatic gain control system (AGC) was designed and constructed for the prototype Loran C receiver. The AGC is designed to improve the signal-to-signal ratio of the received Loran signals. The AGC design does not require any analog to digital conversion and it utilizes commonly available components. The AGC consists of: (1) a circuit which samples the peak of the envelope of the Loran signal to obtain an AGC voltage for each of three Loran stations, (2) a dc gain circuit to control the overall gain of the AGC system, and (3) an AGC amplification of the input RF signal. The performance of the AGC system was observed in bench and flight tests; it has improved the overall accuracy of the receiver. Improvements in the accuracy of the time difference calculations to within approx. + or - 1.5 microseconds of the observed time differnces for a given position are reported.

  4. High current gain transistor laser

    NASA Astrophysics Data System (ADS)

    Liang, Song; Qiao, Lijun; Zhu, Hongliang; Wang, Wei

    2016-06-01

    A transistor laser (TL), having the structure of a transistor with multi-quantum wells near its base region, bridges the functionality gap between lasers and transistors. However, light emission is produced at the expense of current gain for all the TLs reported up to now, leading to a very low current gain. We propose a novel design of TLs, which have an n-doped InP layer inserted in the emitter ridge. Numerical studies show that a current flow aperture for only holes can be formed in the center of the emitter ridge. As a result, the common emitter current gain can be as large as 143.3, which is over 15 times larger than that of a TL without the aperture. Besides, the effects of nonradiative recombination defects can be reduced greatly because the flow of holes is confined in the center region of the emitter ridge.

  5. High current gain transistor laser

    PubMed Central

    Liang, Song; Qiao, Lijun; Zhu, Hongliang; Wang, Wei

    2016-01-01

    A transistor laser (TL), having the structure of a transistor with multi-quantum wells near its base region, bridges the functionality gap between lasers and transistors. However, light emission is produced at the expense of current gain for all the TLs reported up to now, leading to a very low current gain. We propose a novel design of TLs, which have an n-doped InP layer inserted in the emitter ridge. Numerical studies show that a current flow aperture for only holes can be formed in the center of the emitter ridge. As a result, the common emitter current gain can be as large as 143.3, which is over 15 times larger than that of a TL without the aperture. Besides, the effects of nonradiative recombination defects can be reduced greatly because the flow of holes is confined in the center region of the emitter ridge. PMID:27282466

  6. Welfare Gains from Financial Liberalization

    PubMed Central

    Townsend, Robert M.; Ueda, Kenichi

    2010-01-01

    Financial liberalization has been a controversial issue, as empirical evidence for growth enhancing effects is mixed. Here, we find sizable welfare gains from liberalization (cost to repression), though the gain in economic growth is ambiguous. We take the view that financial liberalization is a government policy that alters the path of financial deepening, while financial deepening is endogenously chosen by agents given a policy and occurs in transition towards a distant steady state. This history-dependent view necessitates the use of simulation analysis based on a growth model. Our application is a specific episode: Thailand from 1976 to 1996. PMID:20806055

  7. High gain photoconductive semiconductor switching

    SciTech Connect

    Zutavern, F.J.; Loubriel, G.M.; O'Malley, M.W.; Helgeson, W.D.; McLaughlin, D.L.

    1991-01-01

    Switching properties are reported for high gain photoconductive semiconductor switches (PCSS). A 200 ps pulse width laser was used in tests to examine the relations between electric field, rise time, delay, and minimum optical trigger energy for switches which reached 80 kV in a 50 {Omega} transmission line with rise times as short as 600 ps. Infrared photoluminescence was imaged during high gain switching providing direct evidence for current filamentation. Implications of these measurements for the theoretical understanding and practical development of these switches are discussed. 16 refs., 10 figs.

  8. The Gains from Vertical Scaling

    ERIC Educational Resources Information Center

    Briggs, Derek C.; Domingue, Ben

    2013-01-01

    It is often assumed that a vertical scale is necessary when value-added models depend upon the gain scores of students across two or more points in time. This article examines the conditions under which the scale transformations associated with the vertical scaling process would be expected to have a significant impact on normative interpretations…

  9. Classroom Composition and Achievement Gains.

    ERIC Educational Resources Information Center

    Leiter, Jeffrey

    1983-01-01

    Third-grade students in high ability groups in mathematics achieved greater gains than students in low ability groups. The opposite results occurred in reading achievement. Possible reasons for this difference include different instructional techniques for reading and math and the effect of home environment on learning. (IS)

  10. Photomultiplier tube gain regulating system

    DOEpatents

    Johnson, Wayne F.

    1976-01-01

    This invention relates to an improved system for regulating the gain of a photomultiplier tube, and was designed for use with the photomultiplier tubes of a GeMSAEC fast analyzers. It has the following advantages over the prior system: noise is virtually eliminated; sample analysis can begin after 3 to 4 revolutions of the rotor; fluorescent and light scattering solutions can be used as a reference; and the reference solution can be in any cuvette on the rotor.

  11. Cassegrain-Antenna Gain Improvement

    NASA Technical Reports Server (NTRS)

    Galindo, V.; Cha, A. G.; Mittra, R.

    1986-01-01

    Modified antenna feed with dual-shaped subreflectors yields 10-to20-percent improvement in efficiency of existing large-aperture paraboloidal or Cassegrainian antennas. Such offset dual-shaped subreflector (DSS) feed brings gain of existing paraboloid or Cassegrain antennas up to that of reflector antennas of more recent design at cost considerably lower than for reshaping existing reflecting surfaces. Mathematical procedures developed for synthesizing nearly optimum shapes for DSS elements of new feeds.

  12. Gain lever characterization in monolithically integrated diode lasers

    NASA Astrophysics Data System (ADS)

    Pocha, Michael; Bond, Tiziana; Welty, Rebecca; Vernon, Stephen; Kallman, Jeffrey; Behymer, Elaine

    2005-04-01

    Gain Lever, an effect for enhancing amplitude modulation (AM) efficiency in multisection laser diodes1, has been characterized in InGaAs DQW edge emitting lasers that are integrated with passive waveguides. Specifically designed structures which give a range of split ratios from 1:1 to 9:1 have been fabricated and measured to fully characterize the parameter space for operation in the gain lever mode. Additionally the experimental results are compared to a hybrid 3-D simulation involving effective index method (EIM) reduction to 2-D. Gains greater than 6 dB in the AM efficiency can be achieved within the appropriate operating range, but this gain drops rapidly as the parameter range is exceeded. High speed RF modulation with significant gain is, in principle, possible if proper biasing and modulation conditions are used. This phenomenon can also be useful for high-speed digital information transmission.

  13. Additional Financial Resources for Education.

    ERIC Educational Resources Information Center

    Hubbard, Ben C.

    This paper discusses the continuing need for additional educational funds and suggests that the only way to gain these funds is through concerted and persistent political efforts by supporters of education at both the federal and state levels. The author first points out that for many reasons declining enrollment may not decrease operating costs…

  14. Fresnel reflection from a cavity with net roundtrip gain

    SciTech Connect

    Mansuripur, Tobias S.; Mansuripur, Masud

    2014-03-24

    A planewave incident on an active etalon with net roundtrip gain may be expected to diverge in field amplitude, yet applying the Fresnel formalism to Maxwell's equations admits a convergent solution. We describe this solution mathematically and provide additional insight by demonstrating the response of such a cavity to an incident beam of light. Cavities with net roundtrip gain have often been overlooked in the literature, and a clear understanding of their behavior yields insight to negative refraction in nonmagnetic media, a duality between loss and gain, amplified total internal reflection, and the negative-index lens.

  15. Effects of Gain Changes on RPM Performance

    SciTech Connect

    Lousteau, Angela L; York, Robbie Lynn; Livesay, Jake

    2012-03-01

    gains are less than 5% (Fig. 6). ORNL does not consider this slight increase in sensitivity to be a worthwhile pursuit. Second, increasing the ULD will increase sensitivity a few percent (Fig. 7); however, it is not clear that the slight increase in sensitivity is worth the effort required to make the change (e.g., reliability, cost, etc.). Additionally, while the monitor would be more sensitive to HEU, it would also be more sensitive to NORM. Third, the sensitivity of the system remains approximately the same whether it is calibrated to a small source on contact or a large source far away (Fig. 6). This affirms that no changes to the existing calibration procedure are necessary.

  16. Commutated automatic gain control system

    NASA Technical Reports Server (NTRS)

    Yost, S. R.

    1982-01-01

    A commutated automatic gain control (AGC) system was designed and built for a prototype Loran C receiver. The receiver uses a microcomputer to control a memory aided phase-locked loop (MAPLL). The microcomputer also controls the input/output, latitude/longitude conversion, and the recently added AGC system. The circuit designed for the AGC is described, and bench and flight test results are presented. The AGC circuit described actually samples starting at a point 40 microseconds after a zero crossing determined by the software lock pulse ultimately generated by a 30 microsecond delay and add network in the receiver front end envelope detector.

  17. Scalar gain interpretation of large order filters

    NASA Technical Reports Server (NTRS)

    Mason, Paul A. C.; Mook, D. Joseph

    1993-01-01

    A technique is developed which demonstrates how to interpret a large fully-populated filter gain matrix as a set of scalar gains. The inverse problem is also solved, namely, how to develop a large-order filter gain matrix from a specified set of scalar gains. Examples are given to illustrate the method.

  18. A gain-coefficient switched Alexandrite laser

    NASA Astrophysics Data System (ADS)

    Lee, Chris J.; van der Slot, Peter J. M.; Boller, Klaus-J.

    2013-01-01

    We report on a gain-coefficient switched Alexandrite laser. An electro-optic modulator is used to switch between high and low gain states by making use of the polarization dependent gain of Alexandrite. In gain-coefficient switched mode, the laser produces 85 ns pulses with a pulse energy of 240 mJ at a repetition rate of 5 Hz.

  19. Unidirectional high gain brake stop

    NASA Technical Reports Server (NTRS)

    Lang, David J. (Inventor)

    1987-01-01

    This invention relates to a unidirectional high gain brake arrangement that includes in combination a shaft mounted for rotation within a housing. The shaft is rotatable in either direction. A brake is selectively releasably coupled to the housing and to the shaft. The brake has a first member. An intermittent motion device is respectively coupled through the first member to the housing and through a one-way clutch to the shaft. The brake also has a second member that is mechanically coupled to the first brake member and to the housing. The intermittent motion device causes the brake to be activated by movement imparted to the first brake member after a preset number of revolutions of the shaft in one direction. The brake is released by rotation of the shaft in an opposite direction whereby torque transmitted through the one-way clutch to the first brake member is removed.

  20. High-gain antenna & terrain

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Areas of rocky Martian terrain are seen in this image, taken by the Imager for Mars Pathfinder (IMP) on Sol 2. Portions of a lander petal and deflated airbag are at lower left. The dark disk at center is the high-gain antenna, and the silver cylindrical objects at upper right are part of the antenna's mechanism. An area of relatively smooth terrain is seen at upper right, which may offer clues to how this area was formed, and may be a future target for Sojourner's studies. The black area at lower right and small strip at top center is missing data.

    Mars Pathfinder was developed and managed by the Jet Propulsion Laboratory (JPL) for the National Aeronautics and Space Administration. The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

  1. Sudden gains in behavioural activation for depression.

    PubMed

    Masterson, Ciara; Ekers, David; Gilbody, Simon; Richards, David; Toner-Clewes, Benjamin; McMillan, Dean

    2014-09-01

    Sudden gains have been linked to improved outcomes in cognitive behaviour therapy for depression. The relationship between sudden gains and outcome is less clear in other treatment modalities, including interpersonal psychotherapy and supportive expressive therapy, which may indicate different mechanisms of change between treatment modalities. The current study examined sudden gains in adults meeting diagnostic criteria for depression (N = 40) offered up to 12 sessions of behavioural activation treatment. Sudden gains were found in 42.5% of the sample. Sudden gains occurred early (median pre-gain session 2) and were related to outcome: those who experienced a sudden gain had significantly lower post-treatment scores on the PHQ-9. Furthermore, the proportion meeting the reliable and clinically significant change criteria at end of treatment was higher in the sudden gain group. These findings highlight the importance of understanding the mechanisms by which sudden gains relate to therapy outcome in behavioural activation.

  2. Rationale, design and methods of the Study of Work and Pain (SWAP): a cluster randomised controlled trial testing the addition of a vocational advice service to best current primary care for patients with musculoskeletal pain (ISRCTN 52269669)

    PubMed Central

    2014-01-01

    Background Musculoskeletal pain is a major contributor to short and long term work absence. Patients seek care from their general practitioner (GP) and yet GPs often feel ill-equipped to deal with work issues. Providing a vocational case management service in primary care, to support patients with musculoskeletal problems to remain at or return to work, is one potential solution but requires robust evaluation to test clinical and cost-effectiveness. Methods/Design This protocol describes a cluster randomised controlled trial, with linked qualitative interviews, to investigate the effect of introducing a vocational advice service into general practice, to provide a structured approach to managing work related issues in primary care patients with musculoskeletal pain who are absent from work or struggling to remain in work. General practices (n = 6) will be randomised to offer best current care or best current care plus a vocational advice service. Adults of working age who are absent from or struggling to remain in work due to a musculoskeletal pain problem will be invited to participate and 330 participants will be recruited. Data collection will be through patient completed questionnaires at baseline, 4 and 12 months. The primary outcome is self-reported work absence at 4 months. Incremental cost-utility analysis will be undertaken to calculate the cost per additional QALY gained and incremental net benefits. A linked interview study will explore the experiences of the vocational advice service from the perspectives of GPs, nurse practitioners (NPs), patients and vocational advisors. Discussion This paper presents the rationale, design, and methods of the Study of Work And Pain (SWAP) trial. The results of this trial will provide evidence to inform primary care practice and guide the development of services to provide support for musculoskeletal pain patients with work-related issues. Trial registration Current Controlled Trials ISRCTN52269669. PMID:25012813

  3. Variable Gain Semiconductor Optical Linear Amplifier (OLA)

    NASA Astrophysics Data System (ADS)

    Michie, W. Craig; Kelly, Tony; Tomlinson, Andy; Andonovic, Ivan

    2002-12-01

    The semiconductor optical amplifier (SOA) is a versatile component that can be deployed to meet the expanding applications associated with the introduction of additional functionalities at the optical level in wavelength division multiplexed systems. The future network requires low cost, small footprint, directly controllable amplification throughout the different application layers from long haul through to metro; the intrinsic size and integration capability advantages will ensure that the SOA plays a key role in this evolution. In multi-wavelength gating/amplification applications the gain dynamics, oscillating at timescales comparable to that of the data which is being amplified, introduce issues of pattern dependent waveform distortion (patterning) in single channel, and inter-channel cross-talk in multi-wavelength cases which require management through careful SOA design and understanding of the network application scenarios. In this paper, an optical linear amplifier (OLA) architecture with the unique capability to provide variable gain whilst maintaining linear operation at high output saturation powers will be described. Initial characterisation results for the OLA will be presented.

  4. Temporal Gain Correction for X-ray Calorimeter Spectrometers

    NASA Astrophysics Data System (ADS)

    Porter, F. S.; Chiao, M. P.; Eckart, M. E.; Fujimoto, R.; Ishisaki, Y.; Kelley, R. L.; Kilbourne, C. A.; Leutenegger, M. A.; McCammon, D.; Mitsuda, K.; Sawada, M.; Szymkowiak, A. E.; Takei, Y.; Tashiro, M.; Tsujimoto, M.; Watanabe, T.; Yamada, S.

    2016-07-01

    Calorimetric X-ray detectors are very sensitive to their environment. The boundary conditions can have a profound effect on the gain including heat sink temperature, the local radiation temperature, bias, and the temperature of the readout electronics. Any variation in the boundary conditions can cause temporal variations in the gain of the detector and compromise both the energy scale and the resolving power of the spectrometer. Most production X-ray calorimeter spectrometers, both on the ground and in space, have some means of tracking the gain as a function of time, often using a calibration spectral line. For small gain changes, a linear stretch correction is often sufficient. However, the detectors are intrinsically non-linear and often the event analysis, i.e., shaping, optimal filters etc., add additional non-linearity. Thus for large gain variations or when the best possible precision is required, a linear stretch correction is not sufficient. Here, we discuss a new correction technique based on non-linear interpolation of the energy-scale functions. Using Astro-H/SXS calibration data, we demonstrate that the correction can recover the X-ray energy to better than 1 part in 104 over the entire spectral band to above 12 keV even for large-scale gain variations. This method will be used to correct any temporal drift of the on-orbit per-pixel gain using on-board calibration sources for the SXS instrument on the Astro-H observatory.

  5. Forward ramp & low gain antenna

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Mars Pathfinder's forward rover ramp can be seen successfully unfurled in this color image, taken by the Imager for Mars Pathfinder (IMP) on Sol 3. This ramp was not used for the deployment of the microrover Sojourner, which occurred at the end of Sol 2. When this image was taken, Sojourner was still latched to one of the lander's petals, waiting for the command sequence that would execute its descent off of the lander's petal. The image helped Pathfinder scientists determine whether to deploy the rover using the forward or backward ramps and the nature of the first rover traverse. The metallic object at the lower part of the image is the lander's low-gain antenna. The square at the end of the ramp is one of the spacecraft's magnetic targets. Dust that accumulates on the magnetic targets will later be examined by Sojourner's Alpha Proton X-Ray Spectrometer instrument for chemical analysis. At center, a lander petal is visible.

    spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

  6. Achieving yield gains in wheat.

    PubMed

    Reynolds, Matthew; Foulkes, John; Furbank, Robert; Griffiths, Simon; King, Julie; Murchie, Erik; Parry, Martin; Slafer, Gustavo

    2012-10-01

    Wheat provides 20% of calories and protein consumed by humans. Recent genetic gains are <1% per annum (p.a.), insufficient to meet future demand. The Wheat Yield Consortium brings expertise in photosynthesis, crop adaptation and genetics to a common breeding platform. Theory suggest radiation use efficiency (RUE) of wheat could be increased ~50%; strategies include modifying specificity, catalytic rate and regulation of Rubisco, up-regulating Calvin cycle enzymes, introducing chloroplast CO(2) concentrating mechanisms, optimizing light and N distribution of canopies while minimizing photoinhibition, and increasing spike photosynthesis. Maximum yield expression will also require dynamic optimization of source: sink so that dry matter partitioning to reproductive structures is not at the cost of the roots, stems and leaves needed to maintain physiological and structural integrity. Crop development should favour spike fertility to maximize harvest index so phenology must be tailored to different photoperiods, and sensitivity to unpredictable weather must be modulated to reduce conservative responses that reduce harvest index. Strategic crossing of complementary physiological traits will be augmented with wide crossing, while genome-wide selection and high throughput phenotyping and genotyping will increase efficiency of progeny screening. To ensure investment in breeding achieves agronomic impact, sustainable crop management must also be promoted through crop improvement networks.

  7. Loss restlessness and gain calmness: durable effects of losses and gains on choice switching.

    PubMed

    Yechiam, Eldad; Zahavi, Gal; Arditi, Eli

    2015-08-01

    While the traditional conceptualization of the effect of losses focuses on bias in the subjective weight of losses compared with respective gains, some accounts suggest more global task-related effects of losses. Based on a recent attentional theory, we predicted a positive after-effect of losses on choice switching in later tasks. In two experimental studies, we found increased choice switching rates in tasks with losses compared to tasks with no losses. Additionally, this heightened shifting behavior was maintained in subsequent tasks that do not include losses, a phenomenon we refer to as "loss restlessness." Conversely, gains were found to have an opposite "calming" effect on choice switching. Surprisingly, the loss restlessness phenomenon was observed following an all-losses payoff regime but not after a task with symmetric mixed gains and losses. This suggests that the unresolved mental account following an all-losses regime increases search behavior. Potential implications to macro level phenomena, such as the leverage effect, are discussed. PMID:25348826

  8. Loss restlessness and gain calmness: durable effects of losses and gains on choice switching.

    PubMed

    Yechiam, Eldad; Zahavi, Gal; Arditi, Eli

    2015-08-01

    While the traditional conceptualization of the effect of losses focuses on bias in the subjective weight of losses compared with respective gains, some accounts suggest more global task-related effects of losses. Based on a recent attentional theory, we predicted a positive after-effect of losses on choice switching in later tasks. In two experimental studies, we found increased choice switching rates in tasks with losses compared to tasks with no losses. Additionally, this heightened shifting behavior was maintained in subsequent tasks that do not include losses, a phenomenon we refer to as "loss restlessness." Conversely, gains were found to have an opposite "calming" effect on choice switching. Surprisingly, the loss restlessness phenomenon was observed following an all-losses payoff regime but not after a task with symmetric mixed gains and losses. This suggests that the unresolved mental account following an all-losses regime increases search behavior. Potential implications to macro level phenomena, such as the leverage effect, are discussed.

  9. Nicotine Replacement: Effects on Postcessation Weight Gain.

    ERIC Educational Resources Information Center

    Gross, Janet; And Others

    1989-01-01

    Examined nicotine replacement effects on postcessation weight gain in smoking cessation volunteers. Randomly assigned abstinent subjects to active nicotine or placebo gum conditions for 10 weeks. Analyses revealed strong evidence for gum effect on weight gain, with active gum users gaining mean total of 3.8 pounds compared with 7.8 pounds for…

  10. STADAN antenna gain calibration using radio stars

    NASA Technical Reports Server (NTRS)

    Taylor, R. E.

    1972-01-01

    An antenna gain measurement method was developed which utilizes a signal emitted from a radio star to determine absolute antenna gain at 136 MHz and 400 MHz for antennas in the STADAN network. An error analysis of the radio star method shows that the overall standard deviation uncertainty in antenna gain is + or - 0.6 db (1 sigma).

  11. Determination of optimal gains for constrained controllers

    SciTech Connect

    Kwan, C.M.; Mestha, L.K.

    1993-08-01

    In this report, we consider the determination of optimal gains, with respect to a certain performance index, for state feedback controllers where some elements in the gain matrix are constrained to be zero. Two iterative schemes for systematically finding the constrained gain matrix are presented. An example is included to demonstrate the procedures.

  12. Gestational weight gain among Hispanic women.

    PubMed

    Sangi-Haghpeykar, Haleh; Lam, Kim; Raine, Susan P

    2014-01-01

    To describe gestational weight gain among Hispanic women and to examine psychological, social, and cultural contexts affecting weight gain. A total of 282 Hispanic women were surveyed post-partum before leaving the hospital. Women were queried about their prepregnancy weight and weight gained during pregnancy. Adequacy of gestational weight gain was based on guidelines set by the Institute of Medicine in 2009. Independent risk factors for excessive or insufficient weight gain were examined by logistic regression. Most women were unmarried (59 %), with a mean age of 28.4 ± 6.6 years and an average weight gain of 27.9 ± 13.3 lbs. Approximately 45 % of women had gained too much, 32 % too little, and only 24 % had an adequate amount of weight gain. The mean birth weight was 7.3, 7.9, and 6.8 lbs among the adequate, excessive, and insufficient weight gain groups. Among women who exercised before pregnancy, two-thirds continued to do so during pregnancy; the mean gestational weight gain of those who continued was lower than those who stopped (26.8 vs. 31.4 lbs, p = 0.04). Independent risk factors for excessive weight gain were being unmarried, U.S. born, higher prepregnancy body mass index, and having indifferent or negative views about weight gain. Independent risk factors for insufficient weight gain were low levels of support and late initiation of prenatal care. Depression, stress, and a woman's or her partner's happiness regarding pregnancy were unrelated to weight gain. The results of this study can be used by prenatal programs to identify Hispanic women at risk for excessive or insufficient gestational weight gain.

  13. Small signal gain in DPAL systems

    NASA Astrophysics Data System (ADS)

    Galbally-Kinney, Kristin L.; Maser, Daniel L.; Kessler, William J.; Rawlins, Wilson T.; Davis, Steven J.

    2011-03-01

    In this paper we describe a platform for small signal gain measurements for alkali atom laser systems based on the DPAL excitation method. We present initial results that clearly show the transition from absorption on the alkali atom D1 lines in Cs and Rb to optical transparency and positive gain. The achievement of optical gain is critically dependent upon alkali cell conditions and collision partners. We also present the first spatially resolved gain measurements in a DPAL system. The small signal gain methods described will be valuable tools for power scaling of these laser systems.

  14. Hearing in noisy environments: noise invariance and contrast gain control

    PubMed Central

    Willmore, Ben D B; Cooke, James E; King, Andrew J

    2014-01-01

    Contrast gain control has recently been identified as a fundamental property of the auditory system. Electrophysiological recordings in ferrets have shown that neurons continuously adjust their gain (their sensitivity to change in sound level) in response to the contrast of sounds that are heard. At the level of the auditory cortex, these gain changes partly compensate for changes in sound contrast. This means that sounds which are structurally similar, but have different contrasts, have similar neuronal representations in the auditory cortex. As a result, the cortical representation is relatively invariant to stimulus contrast and robust to the presence of noise in the stimulus. In the inferior colliculus (an important subcortical auditory structure), gain changes are less reliably compensatory, suggesting that contrast- and noise-invariant representations are constructed gradually as one ascends the auditory pathway. In addition to noise invariance, contrast gain control provides a variety of computational advantages over static neuronal representations; it makes efficient use of neuronal dynamic range, may contribute to redundancy-reducing, sparse codes for sound and allows for simpler decoding of population responses. The circuits underlying auditory contrast gain control are still under investigation. As in the visual system, these circuits may be modulated by factors other than stimulus contrast, forming a potential neural substrate for mediating the effects of attention as well as interactions between the senses. PMID:24907308

  15. Molecular analysis of chromosome arm 17q gain in neuroblastoma.

    PubMed

    Janoueix-Lerosey, I; Penther, D; Thioux, M; de Crémoux, P; Derré, J; Ambros, P; Vielh, P; Bénard, J; Aurias, A; Delattre, O

    2000-07-01

    Complete or partial gain of the long arm of chromosome 17 (17q) has been shown recently by molecular cytogenetic techniques to be the most frequent chromosomal change in neuroblastoma and to be associated with adverse prognosis. Few reports, however, have focused on the precise mapping of the commonly overrepresented region. We have investigated 17q gain by the analysis of allelic imbalances at microsatellite loci dispersed along chromosome 17 in a series of 69 neuroblastomas. Allelic imbalances for at least two consecutive loci were observed in 39/59 informative cases, that is in agreement with previously reported frequencies of 17q gain. In a subset of the cases, comparative genomic hybridization analysis established the relationship between these allelic imbalances and the gain of 17q material. A partial 17q gain was observed in 9 cases, delineating a common region of 17q gain between the marker D17S787 (75 cM, 360 cR) and the telomere. In most cases, molecular results were suggestive of partial tri- or tetrasomy, whereas in 4 cases a higher copy number was documented. Our results also confirm that the presence of additional 17q material is closely associated with 1p36 deletion, MYCN amplification, and diploid or tetraploid chromosomal content. Genes Chromosomes Cancer 28:276-284, 2000. PMID:10862033

  16. Pharmacological management of atypical antipsychotic-induced weight gain.

    PubMed

    Baptista, Trino; ElFakih, Yamily; Uzcátegui, Euderruh; Sandia, Ignacio; Tálamo, Eduardo; Araujo de Baptista, Enma; Beaulieu, Serge

    2008-01-01

    Excessive bodyweight gain was reported during the 1950s as an adverse effect of typical antipsychotic drug treatment, but the magnitude of bodyweight gain was found to be higher with the atypical antipsychotic drugs that were introduced after 1990. Clozapine and olanzapine produce the greatest bodyweight gain, ziprasidone and aripiprazole have a neutral influence, and quetiapine and risperidone cause an intermediate effect. In the CATIE study, the percentage of patients with bodyweight gain of >7% compared with baseline differed significantly between the antipsychotic drugs, i.e. 30%, 16%, 14%, 12% and 7% for olanzapine, quetiapine, risperidone, perphenazine (a typical antipsychotic) and ziprasidone, respectively (p<0.001). Appetite stimulation is probably a key cause of bodyweight gain, but genetic polymorphisms modify the bodyweight response during treatment with atypical antipsychotics. In addition to nutritional advice, programmed physical activity, cognitive-behavioural training and atypical antipsychotic switching, pharmacological adjunctive treatments have been assessed to counteract excessive bodyweight gain. In some clinical trials, nizatidine, amantadine, reboxetine, topiramate, sibutramine and metformin proved effective in preventing or reversing atypical antipsychotic-induced bodyweight gain; however, the results are inconclusive since few randomized, placebo-controlled clinical trials have been conducted. Indeed, most studies were short-term trials without adequate statistical power and, in the case of metformin, nizatidine and sibutramine, the results are contradictory. The tolerability profile of these agents is adequate. More studies are needed before formal recommendations on the use of these drugs can be made. Meanwhile, clinicians are advised to use any of these adjunctive treatments according to their individual pharmacological and tolerability profiles, and the patient's personal and family history of bodyweight gain and metabolic dysfunction.

  17. Economic Analysis of Revision Amputation and Replantation Treatment of Finger Amputation Injuries

    PubMed Central

    Sears, Erika Davis; Shin, Ryan; Prosser, Lisa A.; Chung, Kevin C.

    2014-01-01

    Background The purpose of this study was to perform a cost-utility analysis to compare revision amputation and replantation treatment of finger amputation injuries across a spectrum of injury scenarios. Methods The study was conducted from the societal perspective. Decision tree models were created for the reference case (two finger amputation injury) and seven additional injury scenarios for comparison. Inputs included cost, quality of life, and probability of each health state. A web-based time trade-off survey was created to determine quality adjusted life years (QALYs) for health states; 685 nationally representative adult community members were invited to participate in the survey. Overall cost and QALYs for revision amputation and replantation were calculated for each decision tree. An incremental cost effectiveness ratio (ICER) was calculated if a treatment was more costly but more effective. Results We had a 64% response rate (n=437). Replantation treatment had greater costs and QALYs compared to revision amputation in all injury scenarios. Replantation of single digit injuries had the highest ICER ($136,400/QALY gained). Replantation of three and four digit amputation injuries had relatively low cost-benefit ratios ($27,100 and $23,800/QALY respectively). Replantation for distal thumb amputation had a relatively low ICER ($26,300/QALY) compared to replantation of non-thumb distal amputations ($60,200/QALY). Conclusions The relative cost per QALY gained with replantation treatment varied greatly among the injury scenarios. Situations in which indications for replantation are debated had higher cost per QALY gained. This study highlights variability in value for replantation among different injury scenarios. PMID:24352209

  18. Optical antenna gain. I - Transmitting antennas

    NASA Technical Reports Server (NTRS)

    Klein, B. J.; Degnan, J. J.

    1974-01-01

    The gain of centrally obscured optical transmitting antennas is analyzed in detail. The calculations, resulting in near- and far-field antenna gain patterns, assume a circular antenna illuminated by a laser operating in the TEM-00 mode. A simple polynomial equation is derived for matching the incident source distribution to a general antenna configuration for maximum on-axis gain. An interpretation of the resultant gain curves allows a number of auxiliary design curves to be drawn that display the losses in antenna gain due to pointing errors and the cone angle of the beam in the far field as a function of antenna aperture size and its central obscuration. The results are presented in a series of graphs that allow the rapid and accurate evaluation of the antenna gain which may then be substituted into the conventional range equation.

  19. Random lasing with spatially nonuniform gain

    NASA Astrophysics Data System (ADS)

    Fan, Ting; Lü, Jiantao

    2016-07-01

    Spatial and spectral properties of random lasing with spatially nonuniform gain were investigated in two-dimensional (2D) disordered medium. The pumping light was described by an individual electric field and coupled into the rate equations by using the polarization equation. The spatially nonuniform gain comes from the multiple scattering of this pumping light. Numerical simulation of the random system with uniform and nonuniform gain were performed both in weak and strong scattering regime. In weak scattering sample, all the lasing modes correspond to those of the passive system whether the nonuniform gain is considered. However, in strong scattering regime, new lasing modes appear with nonuniform gain as the localization area changes. Our results show that it is more accurate to describe the random lasing behavior with introducing the nonuniform gain origins from the multiple light scattering.

  20. Unstable resonators with a distributed focusing gain.

    PubMed

    Ferguson, T R

    1994-08-20

    The geometrical optics approximation is used to form a model of axisymmetric unstable resonators having distributed focus, gain, and loss. A tapered reflectivity feedback mirror is included. The rate equations for propagation through the focusing gain medium are derived. A unique grid is found for propagation without interpolation along eigenrays in each direction. Numerical examples show the effects of distributed gain and focus on the axial and transverse intensity distributions. PMID:20935986

  1. Gestational weight gain trajectories in primary care

    PubMed Central

    Piccinini-Vallis, Helena; Lee-Baggley, Dayna; Stewart, Moira; Ryan, Bridget

    2016-01-01

    Objective To identify gestational weight gain trajectories, stratified by prepregnancy body mass index (BMI), of women with singleton pregnancies who received prenatal care in a primary care setting, and to compare these trajectories with the 2009 Institute of Medicine gestational weight gain recommendations. Design Retrospective cohort study. Setting Halifax, NS. Participants Women who received prenatal care at the Dalhousie Family Medicine clinics in Halifax from 2009 to 2013. Main outcome measures For each prenatal visit, gestational age and weight measurements were obtained. Multilevel modeling was used to analyze the gestational weight gain trajectories. The upper limit of the guideline-recommended weekly gestational weight gain was compared with the 95% CI of the observed mean weekly gestational weight gain for each prepregnancy BMI category. Results A total of 280 women were included in the analyses. There was a significant interaction between prepregnancy BMI category and gestational weight gain over time (P < .001), with gestational weight gain being significantly lower among women with prepregnancy BMI of 30.0 kg/m2 or greater compared with those with BMI of 18.5 to less than 25.0 kg/m2 and 25.0 to less than 30.0 kg/m2. When comparing women’s weight gain with the recommendations, women with prepregnancy BMI of 25.0 to less than 30.0 kg/m2 had the most guideline discordance, deviating from the weight gain recommendations at 20 weeks’ gestation. Conclusion These results are relevant and of benefit to women and clinicians wishing to address excess gestational weight gain, and to researchers and policy makers developing interventions aimed at curbing gestational weight gain in primary care. Although our results showed women with prepregnancy BMI of 25.0 to less than 30.0 kg/m2 gained the most excess, guideline-discordant weight, interventions should target all women planning or experiencing a pregnancy.

  2. Measurement of Antenna Bore-Sight Gain

    NASA Technical Reports Server (NTRS)

    Fortinberry, Jarrod; Shumpert, Thomas

    2016-01-01

    The absolute or free-field gain of a simple antenna can be approximated using standard antenna theory formulae or for a more accurate prediction, numerical methods may be employed to solve for antenna parameters including gain. Both of these methods will result in relatively reasonable estimates but in practice antenna gain is usually verified and documented via measurements and calibration. In this paper, a relatively simple and low-cost, yet effective means of determining the bore-sight free-field gain of a VHF/UHF antenna is proposed by using the Brewster angle relationship.

  3. Error margin for antenna gain measurements

    NASA Technical Reports Server (NTRS)

    Cable, V.

    2002-01-01

    The specification of measured antenna gain is incomplete without knowing the error of the measurement. Also, unless gain is measured many times for a single antenna or over many identical antennas, the uncertainty or error in a single measurement is only an estimate. In this paper, we will examine in detail a typical error budget for common antenna gain measurements. We will also compute the gain uncertainty for a specific UHF horn test that was recently performed on the Jet Propulsion Laboratory (JPL) antenna range. The paper concludes with comments on these results and how they compare with the 'unofficial' JPL range standard of +/- ?.

  4. Very high gain Nd:YLF amplifiers

    SciTech Connect

    Knights, M.G.; Thomas, M.D.; Chicklis, E.P.; Rines, G.A.; Seka, W.

    1988-05-01

    The authors report on high gain Nd:YLF rod amplifiers in which single-pass, small signal gains of over 1700 have been obtained along with stored energy densitiesgreater than or equal to0.4J/cm/sup 3/. The ability of Nd:YLF amplifiers to support such gains is a result of high parasitic oscillation thresholds, due primarily to the low refractive index of the material. These results suggest that Nd:YLF is an excellent candidate for amplifiers where high specific stored energies and/or very high gains are required.

  5. Coding gains and error rates from the Big Viterbi Decoder

    NASA Technical Reports Server (NTRS)

    Onyszchuk, I. M.

    1991-01-01

    A prototype hardware Big Viterbi Decoder (BVD) was completed for an experiment with the Galileo Spacecraft. Searches for new convolutional codes, studies of Viterbi decoder hardware designs and architectures, mathematical formulations, and decompositions of the deBruijn graph into identical and hierarchical subgraphs, and very large scale integration (VLSI) chip design are just a few examples of tasks completed for this project. The BVD bit error rates (BER), measured from hardware and software simulations, are plotted as a function of bit signal to noise ratio E sub b/N sub 0 on the additive white Gaussian noise channel. Using the constraint length 15, rate 1/4, experimental convolutional code for the Galileo mission, the BVD gains 1.5 dB over the NASA standard (7,1/2) Maximum Likelihood Convolution Decoder (MCD) at a BER of 0.005. At this BER, the same gain results when the (255,233) NASA standard Reed-Solomon decoder is used, which yields a word error rate of 2.1 x 10(exp -8) and a BER of 1.4 x 10(exp -9). The (15, 1/6) code to be used by the Cometary Rendezvous Asteroid Flyby (CRAF)/Cassini Missions yields 1.7 dB of coding gain. These gains are measured with respect to symbols input to the BVD and increase with decreasing BER. Also, 8-bit input symbol quantization makes the BVD resistant to demodulated signal-level variations which may cause higher bandwidth than the NASA (7,1/2) code, these gains are offset by about 0.1 dB of expected additional receiver losses. Coding gains of several decibels are possible by compressing all spacecraft data.

  6. Correcting the Normalized Gain for Guessing

    ERIC Educational Resources Information Center

    Stewart, John; Stewart, Gay

    2010-01-01

    The normalized gain, "g", has been an important tool for the characterization of conceptual improvement in physics courses since its use in Hake's extensive study on conceptual learning in introductory physics. The normalized gain is calculated from the score on a pre-test administered before instruction and a post-test administered after…

  7. Studies on pressure-gain combustion engines

    NASA Astrophysics Data System (ADS)

    Matsutomi, Yu

    Various aspects of the pressure-gain combustion engine are investigated analytically and experimentally in the current study. A lumped parameter model is developed to characterize the operation of a valveless pulse detonation engine. The model identified the function of flame quenching process through gas dynamic process. By adjusting fuel manifold pressure and geometries, the duration of the air buffer can be effectively varied. The parametric study with the lumped parameter model has shown that engine frequency of up to approximately 15 Hz is attainable. However, requirements for upstream air pressure increases significantly with higher engine frequency. The higher pressure requirement indicates pressure loss in the system and lower overall engine performance. The loss of performance due to the pressure loss is a critical issue for the integrated pressure-gain combustors. Two types of transitional methods are examined using entropy-based models. An accumulator based transition has obvious loss due to sudden area expansion, but it can be minimized by utilizing the gas dynamics in the combustion tube. An ejector type transition has potential to achieve performance beyond the limit specified by a single flow path Humphrey cycle. The performance of an ejector was discussed in terms of apparent entropy and mixed flow entropy. Through an ideal ejector, the apparent part of entropy increases due to the reduction in flow unsteadiness, but entropy of the mixed flow remains constant. The method is applied to a CFD simulation with a simple manifold for qualitative evaluation. The operation of the wave rotor constant volume combustion rig is experimentally examined. The rig has shown versatility of operation for wide range of conditions. Large pressure rise in the rotor channel and in a section of the exhaust duct are observed even with relatively large leakage gaps on the rotor. The simplified analysis indicated that inconsistent combustion is likely due to insufficient

  8. Sudden Gains During Therapy of Social Phobia

    PubMed Central

    Hofmann, Stefan G.; Schulz, Stefan M.; Meuret, Alicia E.; Moscovitch, David A.; Suvak, Michael

    2007-01-01

    The present study investigated the phenomenon of sudden gains in 107 participants with social phobia (social anxiety disorder) who received either cognitive–behavioral group therapy or exposure group therapy without explicit cognitive interventions, which primarily used public speaking situations as exposure tasks. Twenty-two out of 967 session-to-session intervals met criteria for sudden gains, which most frequently occurred in Session 5. Individuals with sudden gains showed similar improvements in the 2 treatment groups. Although cognitive–behavioral therapy was associated with more cognitive changes than exposure therapy, cognitive changes did not precede sudden gains. In general, the results of this study question the clinical significance of sudden gains in social phobia treatment. PMID:16881776

  9. Gain recovery dynamics in semiconductor optical amplifiers with distributed feedback grating under assist light injection

    NASA Astrophysics Data System (ADS)

    Qin, Cui; Zhao, Jing; Yu, Huilong; Zhang, Jian

    2016-07-01

    The gain recovery dynamic characteristics of the semiconductor optical amplifier (SOA) with distributed feedback (DFB) grating are theoretically investigated. The interaction of the grating structure and the assist light is used to accelerate the gain recovery process in the SOA. The effects of the assist light that is injected into the SOA with DFB structure on the gain recovery dynamics, the steady-state carrier density, and field intensity distributions are analyzed, respectively. Results show that the recovery time in the DFB SOA is successfully reduced by injecting relatively high power assist light, whose wavelength is set at the gain region. Finally, under assist light injection, the effects of DFB grating on the gain recovery process are also discussed. It is shown that the gain recovery in the SOA with DFB grating is faster than that in the SOA without DFB grating. In addition, the coupling factor in the DFB grating structure can be optimized to shorten the gain recovery time.

  10. Metal Additive Manufacturing: A Review

    NASA Astrophysics Data System (ADS)

    Frazier, William E.

    2014-06-01

    This paper reviews the state-of-the-art of an important, rapidly emerging, manufacturing technology that is alternatively called additive manufacturing (AM), direct digital manufacturing, free form fabrication, or 3D printing, etc. A broad contextual overview of metallic AM is provided. AM has the potential to revolutionize the global parts manufacturing and logistics landscape. It enables distributed manufacturing and the productions of parts-on-demand while offering the potential to reduce cost, energy consumption, and carbon footprint. This paper explores the material science, processes, and business consideration associated with achieving these performance gains. It is concluded that a paradigm shift is required in order to fully exploit AM potential.

  11. High gain holmium-doped fibre amplifiers.

    PubMed

    Simakov, Nikita; Li, Zhihong; Jung, Yongmin; Daniel, Jae M O; Barua, Pranabesh; Shardlow, Peter C; Liang, Sijing; Sahu, Jayanta K; Hemming, Alexander; Clarkson, W Andrew; Alam, Shaif-Ul; Richardson, David J

    2016-06-27

    We investigate the operation of holmium-doped fibre amplifiers (HDFAs) in the 2.1 µm spectral region. For the first time we demonstrate a diode-pumped HDFA. This amplifier provides a peak gain of 25 dB at 2040 nm with a 15 dB gain window spanning the wavelength range 2030 - 2100 nm with an external noise figure (NF) of 4-6 dB. We also compare the operation of HDFAs when pumped at 1950 nm and 2008 nm. The 1950 nm pumped HDFA provides 41 dB peak gain at 2060 nm with 15 dB of gain spanning the wavelength range 2050 - 2120 nm and an external NF of 7-10 dB. By pumping at the longer wavelength of 2008 nm the gain bandwidth of the amplifier is shifted to longer wavelengths and using this architecture a HDFA was demonstrated with a peak gain of 39 dB at 2090 nm and 15 dB of gain spanning the wavelength range 2050 - 2150 nm. The external NF over this wavelength range was 8-14 dB. PMID:27410557

  12. Total heat gain and the split between radiant and convective heat gain from office and laboratory equipment in buildings

    SciTech Connect

    Hosni, M.H.; Jones, B.W.; Sipes, J.M.; Xu, Y.

    1998-10-01

    An accurate determination of the cooling load is important in the proper sizing of air-conditioning equipment. Improvements on the thermal insulation characteristics of building materials and recent advances in building envelope systems have reduced the building cooling load from external sources. However, the number of internal cooling load sources have increased due to the addition of various office and laboratory equipment (e.g., microcomputer, monitor, printer copier, scanner, overhead projector, microwave oven, incubator, etc.). In this article, typical office and laboratory equipment such as desktop computers (with a Pentium and a 486DX2-33 processor), monitors, a copier, a laser printer, and a biological incubator are evaluated to determine the total heat gain and the split between radiant and convective heat gain from these items. In addition, two standard objects with well-defined radiant heat loss characteristics, a heated flat slab, and a heated sphere are used to verify the accuracy of measurement and data reduction procedures. The total heat gain from tested office equipment was significantly less than the name plate ratings even when operated continuously. The actual power consumption ranged from 14% to 36% of the name plate ratings. Thus, care must be taken when using equipment nameplate ratings in estimating total heat gain for air-conditioning equipment sizing.

  13. Temporal evolution of "automatic gain-scaling".

    PubMed

    Pruszynski, J Andrew; Kurtzer, Isaac; Lillicrap, Timothy P; Scott, Stephen H

    2009-08-01

    The earliest neural response to a mechanical perturbation, the short-latency stretch response (R1: 20-45 ms), is known to exhibit "automatic gain-scaling" whereby its magnitude is proportional to preperturbation muscle activity. Because gain-scaling likely reflects an intrinsic property of the motoneuron pool (via the size-recruitment principle), counteracting this property poses a fundamental challenge for the nervous system, which must ultimately counter the absolute change in load regardless of the initial muscle activity (i.e., show no gain-scaling). Here we explore the temporal evolution of gain-scaling in a simple behavioral task where subjects stabilize their arm against different background loads and randomly occurring torque perturbations. We quantified gain-scaling in four elbow muscles (brachioradialis, biceps long, triceps lateral, triceps long) over the entire sequence of muscle activity following perturbation onset-the short-latency response, long-latency response (R2: 50-75 ms; R3: 75-105 ms), early voluntary corrections (120-180 ms), and steady-state activity (750-1250 ms). In agreement with previous observations, we found that the short-latency response demonstrated substantial gain-scaling with a threefold increase in background load resulting in an approximately twofold increase in muscle activity for the same perturbation. Following the short-latency response, we found a rapid decrease in gain-scaling starting in the long-latency epoch ( approximately 75-ms postperturbation) such that no significant gain-scaling was observed for the early voluntary corrections or steady-state activity. The rapid decrease in gain-scaling supports our recent suggestion that long-latency responses and voluntary control are inherently linked as part of an evolving sensorimotor control process through similar neural circuitry.

  14. Active rc filter permits easy trade-off of amplifier gain and sensitivity to gain

    NASA Technical Reports Server (NTRS)

    Kerwin, W. J.; Shaffer, C. V.

    1968-01-01

    Passive RC network was designed with zeros of transmission in the right half of the complex frequency plane in the feedback loop of a simple negative-gain amplifier. The proper positioning provides any desired trade-off between amplifier gain and sensitivity to amplifier gain.

  15. Provider advice about pregnancy weight gain and adequacy of weight gain.

    PubMed

    Ferrari, Renée M; Siega-Riz, Anna Maria

    2013-02-01

    To explore the association between health care provider advice about weight gain and gestational weight gain. Using data from a prospective cohort study, we explored the association between provider advice about weight gain in pregnancy with weight gain adequacy among 1,454 pregnant women. Provider advice was measured by maternal self-report at 27-30 weeks' gestation. Linear and Poisson regression were used to explore associations. Seventy-eight percent of the women gained outside current recommendations. Fifty-one percent reported receiving weight gain advice from a health care provider. Adjusted Generalized Linear Model (GLM) estimates showed weak effect of provider advice on inadequate or excessive gain (Relative Risk (RR) 0.96, 95% CI 0.74, 1.26 for inadequate gain and RR 1.01, 95% CI 0.97, 1.06 for excessive gain). There is a need for more women to hear about their targeted weight gains during pregnancy and the present advice that exists does little to influence actual gains. Further studies are warranted to find better strategies for providers to motivate their patients to gain weight within the appropriate ranges.

  16. TCAD simulation of Low Gain Avalanche Detectors

    NASA Astrophysics Data System (ADS)

    Dalal, Ranjeet; Jain, Geetika; Bhardwaj, Ashutosh; Ranjan, Kirti

    2016-11-01

    In the present work, detailed simulation using Technology Computer Aided Design (TCAD) tool, Silvaco for non-irradiated and irradiated LGAD (Low Gain Avalanche Detector) devices has been carried out. The effects of different design parameters and proton irradiation on LGAD operation are discussed in detail. An already published effective two trap bulk damage model is used to simulate the radiation damage without implementing any acceptor removal term. The TCAD simulation for irradiated LGAD devices produce decreasing gain with increasing fluence, similar to the measurement results. The space charge density and electric field distribution are used to illustrate the possible reasons for the degradation of gain of the irradiated LGAD devices.

  17. Weight Gain following Pallidal Deep Brain Stimulation: A PET Study.

    PubMed

    Sauleau, Paul; Drapier, Sophie; Duprez, Joan; Houvenaghel, Jean-François; Dondaine, Thibaut; Haegelen, Claire; Drapier, Dominique; Jannin, Pierre; Robert, Gabriel; Le Jeune, Florence; Vérin, Marc

    2016-01-01

    The mechanisms behind weight gain following deep brain stimulation (DBS) surgery seem to be multifactorial and suspected depending on the target, either the subthalamic nucleus (STN) or the globus pallidus internus (GPi). Decreased energy expenditure following motor improvement and behavioral and/or metabolic changes are possible explanations. Focusing on GPi target, our objective was to analyze correlations between changes in brain metabolism (measured with PET) and weight gain following GPi-DBS in patients with Parkinson's disease (PD). Body mass index was calculated and brain activity prospectively measured using 2-deoxy-2[18F]fluoro-D-glucose PET four months before and four months after the start of GPi-DBS in 19 PD patients. Dopaminergic medication was included in the analysis to control for its possible influence on brain metabolism. Body mass index increased significantly by 0.66 ± 1.3 kg/m2 (p = 0.040). There were correlations between weight gain and changes in brain metabolism in premotor areas, including the left and right superior gyri (Brodmann area, BA 6), left superior gyrus (BA 8), the dorsolateral prefrontal cortex (right middle gyrus, BAs 9 and 46), and the left and right somatosensory association cortices (BA 7). However, we found no correlation between weight gain and metabolic changes in limbic and associative areas. Additionally, there was a trend toward a correlation between reduced dyskinesia and weight gain (r = 0.428, p = 0.067). These findings suggest that, unlike STN-DBS, motor improvement is the major contributing factor for weight gain following GPi-DBS PD, confirming the motor selectivity of this target. PMID:27070317

  18. Weight Gain following Pallidal Deep Brain Stimulation: A PET Study

    PubMed Central

    Sauleau, Paul; Drapier, Sophie; Duprez, Joan; Houvenaghel, Jean-François; Dondaine, Thibaut; Haegelen, Claire; Drapier, Dominique; Jannin, Pierre; Robert, Gabriel; Le Jeune, Florence; Vérin, Marc

    2016-01-01

    The mechanisms behind weight gain following deep brain stimulation (DBS) surgery seem to be multifactorial and suspected depending on the target, either the subthalamic nucleus (STN) or the globus pallidus internus (GPi). Decreased energy expenditure following motor improvement and behavioral and/or metabolic changes are possible explanations. Focusing on GPi target, our objective was to analyze correlations between changes in brain metabolism (measured with PET) and weight gain following GPi-DBS in patients with Parkinson’s disease (PD). Body mass index was calculated and brain activity prospectively measured using 2-deoxy-2[18F]fluoro-D-glucose PET four months before and four months after the start of GPi-DBS in 19 PD patients. Dopaminergic medication was included in the analysis to control for its possible influence on brain metabolism. Body mass index increased significantly by 0.66 ± 1.3 kg/m2 (p = 0.040). There were correlations between weight gain and changes in brain metabolism in premotor areas, including the left and right superior gyri (Brodmann area, BA 6), left superior gyrus (BA 8), the dorsolateral prefrontal cortex (right middle gyrus, BAs 9 and 46), and the left and right somatosensory association cortices (BA 7). However, we found no correlation between weight gain and metabolic changes in limbic and associative areas. Additionally, there was a trend toward a correlation between reduced dyskinesia and weight gain (r = 0.428, p = 0.067). These findings suggest that, unlike STN-DBS, motor improvement is the major contributing factor for weight gain following GPi-DBS PD, confirming the motor selectivity of this target. PMID:27070317

  19. Frequent chromosomal gains in recurrent juvenile nasopharyngeal angiofibroma.

    PubMed

    Heinrich, Ulf-Rüdiger; Brieger, Jürgen; Gosepath, Jan; Wierzbicka, Magorzata; Sokolov, Maxim; Roth, Yehudah; Szyfter, Witold; Bittinger, Fernando; Mann, Wolf J

    2007-06-01

    Juvenile nasopharyngeal angiofibroma (JNA) is a rare benign tumor, mostly affecting adolescent males. Some patients develop recurrences after surgery independently of completeness of removal. Only very limited data concerning underlying chromosomal changes are available. We therefore analyzed samples of 22 JNAs, including six recurrences, with comparative genomic hybridization (CGH). Additionally, quantitative image cytometry was used for measurement of DNA aneuploidy in representative samples. Of the 13 primary JNAs without later recurrence, DNA gains were identified on autosomes in only two samples. Four patients with one or two recurrences were included in the study; for one of these, no material of the primary tumor was available for analysis. Looking at autosomes, two of the three available primaries displayed multiple gains; in one of those, two additional losses were observed. Multiple gains were detected in two of the four first recurrences, but none in the two second recurrences. Across all 22 samples, gains occurred in more than one sample on chromosomes arms 1p, 9q, 10q, 12q, 16p, 16q, 17q, 19p, 19q, 20q, and 22q. Losses were found in a single case exclusively on chromosome 4. Sex chromosomes were frequently affected in both primary tumors and recurrences. There was no correlation among tumor staging, age, and DNA amplification. No DNA aneuploidy was detected, a finding in accordance with the generally benign characteristics of JNAs. Our observations suggest that in JNA the activation of oncogenes is more likely than the inactivation of tumor suppressor genes. Autosomal gains in the primary tumor should be further evaluated as markers for a potentially increased risk of recurrence after surgical removal in this entity.

  20. Optical properties of nanowire metamaterials with gain

    NASA Astrophysics Data System (ADS)

    Lima, Joaquim; Adam, Jost; Rego, Davi; Esquerre, Vitaly; Bordo, Vladimir

    2016-11-01

    The transmittance, reflectance and absorption of a nanowire metamaterial with optical gain are numerically simulated and investigated. It is assumed that the metamaterial is represented by aligned silver nanowires embedded into a semiconductor matrix, made of either silicon or gallium phosphide. The gain in the matrix is modeled by adding a negative imaginary part to the dielectric function of the semiconductor. It is found that the optical coefficients of the metamaterial depend on the gain magnitude in a non-trivial way: they can both increase and decrease with gain depending on the lattice constant of the metamaterial. This peculiar behavior is explained by the field redistribution between the lossy metal nanowires and the amplifying matrix material. These findings are significant for a proper design of nanowire metamaterials with low optical losses for diverse applications.

  1. Adolescent drug addiction treatment and weight gain.

    PubMed

    Hodgkins, Candace C; Cahill, Kevin S; Seraphine, Anne E; Frost-Pineda, Kimberly; Gold, Mark S

    2004-01-01

    Neurotransmitter release in the nucleus accumbens use has been linked to self-administration and learning following drug use. This endogenous reward system is also activated following food intake or sex. Therefore, rebound hyperphagia following abstinence may be a mechanism to replenish the release of neurotransmitters in this reward system, leading to increased weight gain and a rise in body mass index during recovery from substance abuse. In this report, we examined the relationship between supervised drug abstinence and increased weight gain among adolescents at a residential substance abuse treatment center. Mean weight change over time was followed by repeated analysis of weight and body mass index. Significant weight gain and body mass index increase was observed during supervised and confirmed abstinence from drug use. Furthermore, significant interactions between tobacco use and primary substance use disorder with weight gain was demonstrated by multivariate analysis of variance.

  2. Organic Causes of Weight Gain and Obesity

    MedlinePlus

    ... Issues Listen Español Text Size Email Print Share Organic Causes of Weight Gain and Obesity Page Content ... as children, before they became heavy. Still other organic factors partly determine which kids can eat anything ...

  3. Probabilistic Cost-Effectiveness Analysis of Vaccination for Mild or Moderate Alzheimer’s Disease

    PubMed Central

    Yang, Kuen-Cheh; Chen, Hsiu-Hsi

    2016-01-01

    Background: Studies on the immunotherapy for Alzheimer’s disease (AD) have increasingly gained attention since 1990s. However, there are pros (preventing of AD) and cons (incurred cost and side effects) regarding the administration of immunotherapy. Up to date, there has been lacking of economic evaluation for immunotherapy of AD. We aimed to assess the cost-effectiveness analysis of the vaccination for AD. Methods: A meta-analysis of randomized control trials after systemic review was conducted to evaluate the efficacy of the vaccine. A Markov decision model was constructed and applied to a 120,000-Taiwanese cohort aged ≥65 years. Person years and quality-adjusted life years (QALY) were computed between the vaccinated group and the the unvaccinated group. Economic evaluation was performed to calculate the incremental cost-effectiveness ratio (ICER) and cost-effectiveness acceptability curve (CEAC). Results: Vaccinated group gained an additional 0.84 life years and 0.56 QALYs over 10-years and an additional 0.35 life years and 0.282 QALYs over 5-years of follow-up. The vaccinated group dominated the unvaccinated group by ICER over 5-years of follow-up. The ICERs of 10-year follow-up for the vaccinated group against the unvaccinated group were $13,850 per QALY and $9,038 per life year gained. Given the threshold of $20,000 of willingness to pay (WTP), the CEAC showed the probability of being cost-effective for vaccination with QALY was 70.7% and 92% for life years gained after 10-years of follow-up. The corresponding figures were 87.3% for QALY and 93.5% for life years gained over 5-years follow-up. Conclusion: The vaccination for AD was cost-effective in gaining QALY and life years compared with no vaccination, under the condition of a reasonable threshold of WTP. PMID:26825097

  4. The Galileo high gain antenna deployment anomaly

    NASA Technical Reports Server (NTRS)

    Johnson, Michael R.

    1994-01-01

    On April 11, 1991, the Galileo spacecraft executed a sequence that would open the spacecraft's High Gain Antenna. The Antenna's launch restraint had been released just after deployment sequence, the antenna, which opens like an umbrella, never reached the fully deployed position. The analyses and tests that followed allowed a conclusive determination of the likely failure mechanisms and pointed to some strategies to use for recovery of the high gain antenna.

  5. Can LENR Energy Gains Exceed 1000?

    NASA Astrophysics Data System (ADS)

    Nagel, David J.

    2011-03-01

    Energy gain is defined as the energy realized from reactions divided by the energy required to produce those reactions. Low Energy Nuclear Reactions (LENR) have already been measured to significantly exceed the energy gain of 10 projected from ITER,possibly 15 years from now. Electrochemical experiments using the Pd-D system have shown energy gains exceeding 10. Gas phase experiments with the Ni-H system were reported to yield energy gains of over 100. Neither of these reports has been adequately verified or reproduced. However, the question in the title still deserves consideration. If, as thought by many, it is possible to trigger nuclear reactions that yield MeV energies with chemical energies of the order of eV, then the most optimistic expectation is that LENR gains could approach one million. Hence, the very tentative answer to the question above is yes. However, if LENR could be initiated with some energy cost, and then continue to ``burn,'' very high energy gains might be realized. Consider a match and a pile of dry logs. The phenomenon termed ``heat after death'' will be examined to see if it might be the initial evidence for nuclear ``burning.''

  6. FEL gain optimisation and spontaneous radiation

    SciTech Connect

    Bali, L.M.; Srivastava, A.; Pandya, T.P.

    1995-12-31

    Colson have evaluated FEL gains for small deviations from perfect electron beam injection, with radiation of the same polarisation as that of the wiggler fields. We find that for optimum gain the polarisation of the optical field should be the same as that of the spontaneous emission under these conditions. With a helical wiggler the axial oscillations resulting from small departures from perfect electron beam injection lead to injection dependent unequal amplitudes and phases of the spontaneous radiation in the two transverse directions. Viewed along the axis therefore the spontaneous emission is elliptically polarised. The azimuth of the ellipse varies with the difference of phase of the two transverse components of spontaneous emission but the eccentricity remains the same. With planar wigglers the spontaneous emission viewed in the axial direction is linearly polarised, again with an injection dependent azimuth. For optimum coherent gain of a radiation field its polarisation characteristics must be the same as those of the spontaneous radiation with both types of wiggler. Thus, with a helical wiggler and the data reported earlier, an increase of 10% in the FEL gain at the fundamental frequency and of 11% at the fifth harmonic has been calculated in the small gain per pass limit. Larger enhancements in gain may result from more favourable values of input parameters.

  7. Central Gain Control in Tinnitus and Hyperacusis

    PubMed Central

    Auerbach, Benjamin D.; Rodrigues, Paulo V.; Salvi, Richard J.

    2014-01-01

    Sensorineural hearing loss induced by noise or ototoxic drug exposure reduces the neural activity transmitted from the cochlea to the central auditory system. Despite a reduced cochlear output, neural activity from more central auditory structures is paradoxically enhanced at suprathreshold intensities. This compensatory increase in the central auditory activity in response to the loss of sensory input is referred to as central gain enhancement. Enhanced central gain is hypothesized to be a potential mechanism that gives rise to hyperacusis and tinnitus, two debilitating auditory perceptual disorders that afflict millions of individuals. This review will examine the evidence for gain enhancement in the central auditory system in response to cochlear damage. Further, it will address the potential cellular and molecular mechanisms underlying this enhancement and discuss the contribution of central gain enhancement to tinnitus and hyperacusis. Current evidence suggests that multiple mechanisms with distinct temporal and spectral profiles are likely to contribute to central gain enhancement. Dissecting the contributions of these different mechanisms at different levels of the central auditory system is essential for elucidating the role of central gain enhancement in tinnitus and hyperacusis and, most importantly, the development of novel treatments for these disorders. PMID:25386157

  8. Context-specific adaptation of saccade gain

    NASA Technical Reports Server (NTRS)

    Shelhamer, Mark; Clendaniel, Richard A.

    2002-01-01

    Previous studies established that vestibular reflexes can have two adapted states (e.g., gain) simultaneously, and that a context cue (e.g., vertical eye position) can switch between the two states. The present study examined this phenomenon of context-specific adaptationfor horizontal saccades, using a variety of contexts. Our overall goal was to assess the efficacy of different context cues in switching between adapted states. A standard double-step paradigm was used to adapt saccade gain. In each experiment, we asked for a simultaneous gain decrease in one context and gain increase in another context, and then determined if a change in the context would invoke switching between the adapted states. Horizontal eye position worked well as a context cue: saccades with the eyes deviated to the right could be made to have higher gains while saccades with the eyes deviated to the left could be made to have lower gains. Vertical eye position was less effective. This suggests that the more closely related a context cue is to the response being adapted, the more effective it is. Roll tilt of the head, and upright versus supine orientations, were somewhat effective in context switching; these paradigms contain orientation of gravity with respect to the head as part of the context.

  9. Cognitive Adaptation of Sonar Gain Control in the Bottlenose Dolphin

    PubMed Central

    Kloepper, Laura N.; Smith, Adam B.; Nachtigall, Paul E.; Buck, John R.; Simmons, James A.; Pacini, Aude F.

    2014-01-01

    Echolocating animals adjust the transmit intensity and receive sensitivity of their sonar in order to regulate the sensation level of their echoes; this process is often termed automatic gain control. Gain control is considered not to be under the animal's cognitive control, but previous investigations studied animals ensonifying targets or hydrophone arrays at predictable distances. To test whether animals maintain gain control at a fixed level in uncertain conditions, we measured changes in signal intensity for a bottlenose dolphin (Tursiops truncatus) detecting a target at three target distances (2.5, 4 and 7 m) in two types of sessions: predictable and unpredictable. Predictable sessions presented the target at a constant distance; unpredictable sessions moved the target randomly between the three target positions. In the predictable sessions the dolphin demonstrated intensity distance compensation, increasing the emitted click intensity as the target distance increased. Additionally, as trials within sessions progressed, the animal adjusted its click intensity even from the first click in a click train, which is consistent with the animal expecting a target at a certain range. In the unpredictable sessions there was no significant difference of intensity with target distance until after the 7th click in a click train. Together, these results demonstrate that the bottlenose dolphin uses learning and expectation for sonar gain control. PMID:25153530

  10. Cognitive adaptation of sonar gain control in the bottlenose dolphin.

    PubMed

    Kloepper, Laura N; Smith, Adam B; Nachtigall, Paul E; Buck, John R; Simmons, James A; Pacini, Aude F

    2014-01-01

    Echolocating animals adjust the transmit intensity and receive sensitivity of their sonar in order to regulate the sensation level of their echoes; this process is often termed automatic gain control. Gain control is considered not to be under the animal's cognitive control, but previous investigations studied animals ensonifying targets or hydrophone arrays at predictable distances. To test whether animals maintain gain control at a fixed level in uncertain conditions, we measured changes in signal intensity for a bottlenose dolphin (Tursiops truncatus) detecting a target at three target distances (2.5, 4 and 7 m) in two types of sessions: predictable and unpredictable. Predictable sessions presented the target at a constant distance; unpredictable sessions moved the target randomly between the three target positions. In the predictable sessions the dolphin demonstrated intensity distance compensation, increasing the emitted click intensity as the target distance increased. Additionally, as trials within sessions progressed, the animal adjusted its click intensity even from the first click in a click train, which is consistent with the animal expecting a target at a certain range. In the unpredictable sessions there was no significant difference of intensity with target distance until after the 7th click in a click train. Together, these results demonstrate that the bottlenose dolphin uses learning and expectation for sonar gain control.

  11. Intron loss and gain in Drosophila.

    PubMed

    Coulombe-Huntington, Jasmin; Majewski, Jacek

    2007-12-01

    Although introns were first discovered almost 30 years ago, their evolutionary origin remains elusive. In this work, we used multispecies whole-genome alignments to map Drosophila melanogaster introns onto 10 other fully sequenced Drosophila genomes. We were able to find 1,944 sites where an intron was missing in one or more species. We show that for most (>80%) of these cases, there is no leftover intronic sequence or any missing exonic sequence, indicating exact intron loss or gain events. We used parsimony to classify these differences as 1,754 intron loss events and 213 gain events. We show that lost and gained introns are significantly shorter than average and flanked by longer than average exons. They also display quite distinct phase distributions and show greater than average similarity between the 5' splice site and its 3' partner splice site. Introns that have been lost in one or more species evolve faster than other introns, occur in slowly evolving genes, and are found adjacent to each other more often than would be expected for independent single losses. Our results support the cDNA recombination mechanism of intron loss, suggest that selective pressures affect site-specific loss rates, and show conclusively that intron gain has occurred within the Drosophila lineage, solidifying the "introns-middle" hypothesis and providing some hints about the gain mechanism.

  12. Gain and energy storage in holmium YLF

    NASA Technical Reports Server (NTRS)

    Storm, Mark E.; Deyst, John P.

    1991-01-01

    It is demonstrated that Q-switched holmium lasers are capable of high-gain and high-energy operation at 300 K. Small-signal gain coefficients of 0.50 and 0.12/cm have been measured in YLF and YAG, respectively. Small-signal gains of 0.50/cm are comparable to those achievable in Nd:YAG and are not typical of low-gain materials. This large gain in the Ho:YLF material is made possible by operating the amplifier in the ground state depletion mode. The amplifier performance data and associated analysis presented demonstrate that efficient energy storage is possible with very high excited state ion densities of the Ho 5I7 upper laser level. This is an important result since upconversion can limit the 5I7 population. Although upconversion was still present in this experiment, it was possible to achieve efficient energy storage, demonstrating that the problem is manageable even at high excitation densities in YLF.

  13. Edemagenic gain and interstitial fluid volume regulation.

    PubMed

    Dongaonkar, R M; Quick, C M; Stewart, R H; Drake, R E; Cox, C S; Laine, G A

    2008-02-01

    Under physiological conditions, interstitial fluid volume is tightly regulated by balancing microvascular filtration and lymphatic return to the central venous circulation. Even though microvascular filtration and lymphatic return are governed by conservation of mass, their interaction can result in exceedingly complex behavior. Without making simplifying assumptions, investigators must solve the fluid balance equations numerically, which limits the generality of the results. We thus made critical simplifying assumptions to develop a simple solution to the standard fluid balance equations that is expressed as an algebraic formula. Using a classical approach to describe systems with negative feedback, we formulated our solution as a "gain" relating the change in interstitial fluid volume to a change in effective microvascular driving pressure. The resulting "edemagenic gain" is a function of microvascular filtration coefficient (K(f)), effective lymphatic resistance (R(L)), and interstitial compliance (C). This formulation suggests two types of gain: "multivariate" dependent on C, R(L), and K(f), and "compliance-dominated" approximately equal to C. The latter forms a basis of a novel method to estimate C without measuring interstitial fluid pressure. Data from ovine experiments illustrate how edemagenic gain is altered with pulmonary edema induced by venous hypertension, histamine, and endotoxin. Reformulation of the classical equations governing fluid balance in terms of edemagenic gain thus yields new insight into the factors affecting an organ's susceptibility to edema.

  14. Edemagenic gain and interstitial fluid volume regulation.

    PubMed

    Dongaonkar, R M; Quick, C M; Stewart, R H; Drake, R E; Cox, C S; Laine, G A

    2008-02-01

    Under physiological conditions, interstitial fluid volume is tightly regulated by balancing microvascular filtration and lymphatic return to the central venous circulation. Even though microvascular filtration and lymphatic return are governed by conservation of mass, their interaction can result in exceedingly complex behavior. Without making simplifying assumptions, investigators must solve the fluid balance equations numerically, which limits the generality of the results. We thus made critical simplifying assumptions to develop a simple solution to the standard fluid balance equations that is expressed as an algebraic formula. Using a classical approach to describe systems with negative feedback, we formulated our solution as a "gain" relating the change in interstitial fluid volume to a change in effective microvascular driving pressure. The resulting "edemagenic gain" is a function of microvascular filtration coefficient (K(f)), effective lymphatic resistance (R(L)), and interstitial compliance (C). This formulation suggests two types of gain: "multivariate" dependent on C, R(L), and K(f), and "compliance-dominated" approximately equal to C. The latter forms a basis of a novel method to estimate C without measuring interstitial fluid pressure. Data from ovine experiments illustrate how edemagenic gain is altered with pulmonary edema induced by venous hypertension, histamine, and endotoxin. Reformulation of the classical equations governing fluid balance in terms of edemagenic gain thus yields new insight into the factors affecting an organ's susceptibility to edema. PMID:18056984

  15. Commissural Gain Control Enhances the Midbrain Representation of Sound Location

    PubMed Central

    Orton, Llwyd David; Papasavvas, Christoforos A.

    2016-01-01

    Accurate localization of sound sources is essential for survival behavior in many species. The inferior colliculi (ICs) are the first point in the auditory pathway where cues used to locate sounds, ie, interaural time differences (ITDs), interaural level differences (ILDs), and pinna spectral cues, are all represented in the same location. These cues are first extracted separately on each side of the midline in brainstem nuclei that project to the ICs. Because of this segregation, each IC predominantly represents stimuli in the contralateral hemifield. We tested the hypothesis that commissural connections between the ICs mediate gain control that enhances sound localization acuity. We recorded IC neurons sensitive to either ITDs or ILDs in anesthetized guinea pig, before, during, and following recovery from deactivation of the contralateral IC by cryoloop cooling or microdialysis of procaine. During deactivation, responses were rescaled by divisive gain change and additive shifts, which reduced the dynamic range of ITD and ILD response functions and the ability of neurons to signal changes in sound location. These data suggest that each IC exerts multiplicative gain control and subtractive shifts over the other IC that enhances the neural representation of sound location. Furthermore, this gain control operates in a similar manner on both ITD- and ILD-sensitive neurons, suggesting a shared mechanism operates across localization cues. Our findings reveal a novel dependence of sound localization on commissural processing. SIGNIFICANCE STATEMENT Sound localization, a fundamental process in hearing, is dependent on bilateral computations in the brainstem. How this information is transmitted from the brainstem to the auditory cortex, through several stages of processing, without loss of signal fidelity, is not clear. We show that the ability of neurons in the auditory midbrain to encode azimuthal sound location is dependent on gain control mediated by the commissure of

  16. Cascade amps for increased subsystem gain

    NASA Astrophysics Data System (ADS)

    Galla, Timothy J.

    1990-05-01

    Selecting cascadable TO-8 amplifiers integrated onto microstrip circuit boards is considered from the point of view of cascaded circuit design techniques and performance characteristics. Cascaded assemblies and circuit boards used in cascaded-amplifier applications are presented. It is noted that TO-8 package constrains allow as many as three transistor stages per housing, utilizing either passive or active biasing with choke decoupling; these configurations can achieve broadband performance with small-signal gain of 15 to 20 dB. Where higher gain levels are required, TO-8 amplifiers can be cascaded as gain blocks and assembled into aluminum housing with connectors. Increased reflection losses resulting in a higher voltage standing wave ratio are analyzed, along with noise minimization techniques. A model showing how to find a TO-8 amplifier's noise figure, input power, and third-order intercept point is described.

  17. High fat diet causes rebound weight gain.

    PubMed

    McNay, David E G; Speakman, John R

    2012-01-01

    Obesity is at epidemic proportions but treatment options remain limited. Treatment of obesity by calorie restriction (CR) despite having initial success often fails due to rebound weight gain. One possibility is that this reflects an increased body weight (BW) set-point. Indeed, high fat diets (HFD) reduce adult neurogenesis altering hypothalamic neuroarchitecture. However, it is uncertain if these changes are associated with weight rebound or if long-term weight management is associated with reversing this. Here we show that obese mice have an increased BW set-point and lowering this set-point is associated with rescuing hypothalamic remodelling. Treating obesity by CR using HFD causes weight loss, but not rescued remodelling resulting in rebound weight gain. However, treating obesity by CR using non-HFD causes weight loss, rescued remodelling and attenuates rebound weight gain. We propose that these phenomena may explain why successful short-term weight loss improves obesity in some people but not in others.

  18. Aromatic Gain in a Supramolecular Polymer.

    PubMed

    Saez Talens, Victorio; Englebienne, Pablo; Trinh, Thuat T; Noteborn, Willem E M; Voets, Ilja K; Kieltyka, Roxanne E

    2015-09-01

    The synergy of aromatic gain and hydrogen bonding in a supramolecular polymer is explored. Partially aromatic bis(squaramide) bolaamphiphiles were designed to self-assemble through a combination of hydrophobic, hydrogen-bonding, and aromatic effects into stiff, high-aspect-ratio fibers. UV and IR spectroscopy show electron delocalization and geometric changes within the squaramide ring indicative of strong hydrogen bonding and aromatic gain of the monomer units. The aromatic contribution to the interaction energy was further supported computationally by nucleus-independent chemical shift (NICS) and harmonic oscillator model of aromaticity (HOMA) indices, demonstrating greater aromatic character upon polymerization: at least 30% in a pentamer. The aromatic gain-hydrogen bonding synergy results in a significant increase in thermodynamic stability and a striking difference in aggregate morphology of the bis(squaramide) bolamphiphile compared to isosteres that cannot engage in this effect. PMID:26179942

  19. Sharing Regional Cooperative Gains From Reusing Effluent for Irrigation

    NASA Astrophysics Data System (ADS)

    Dinar, Ariel; Yaron, Dan; Kannai, Yakar

    1986-03-01

    This paper is concerned with the allocation of cost and benefits from regional cooperation, with respect to reuse of municipal effluent for irrigation at the Ramla region of Israel. An efficient regional solution provides the maximal regional income which has to be redistributed among the town and several farms. Different allocations based on marginal cost pricing and schemes from cooperative game theory like the core, Shapley value, generalized Shapley value, and nucleolus are applied. The town and farm A have the main additional gains according to all allocation schemes presented. Advantages and disadvantages of these allocation schemes are examined in order to suggest a fair and acceptable allocation of the regional cooperative gains. Although no method has been preferred, the marginal cost pricing was found to be unacceptable by the participants. The conclusion is that the theory of cooperative games may provide guidelines while comparing the different solutions.

  20. Relating weight gain and feed:gain of male and female broilers to rearing temperature.

    PubMed

    May, J D; Lott, B D

    2001-05-01

    The effects of environmental temperature on growth and feed:gain were studied in three trials each for male and female broilers. Chicks were reared in a common environment to 21 d of age. At 21 d, they were randomly allocated to 10 environmental chambers. Each chamber was maintained at a constant temperature; the chambers ranged from 12 to 30 C in two-degree increments. The dewpoint was maintained at 18 C, except that relative humidity was not permitted to exceed 82.9%. Body weight was determined at 21 d. Weight gain and feed:gain were determined at 28, 35, 42, and 49 d. The data were analyzed statistically, and regression equations were obtained for weight gain and feed:gain for each sex. Equations were based on body weight and temperature, and the body weight equations were plotted as grams gained per bird per day. Feed:gain increased with increasing weight. The temperature that resulted in the most favorable feed:gain decreased with increasing weight. These results support lower rearing temperatures for optimum growth and feed:gain by large broilers than those of other reports in the literature.

  1. Analytic gain in probabilistic decompression sickness models.

    PubMed

    Howle, Laurens E

    2013-11-01

    Decompression sickness (DCS) is a disease known to be related to inert gas bubble formation originating from gases dissolved in body tissues. Probabilistic DCS models, which employ survival and hazard functions, are optimized by fitting model parameters to experimental dive data. In the work reported here, I develop methods to find the survival function gain parameter analytically, thus removing it from the fitting process. I show that the number of iterations required for model optimization is significantly reduced. The analytic gain method substantially improves the condition number of the Hessian matrix which reduces the model confidence intervals by more than an order of magnitude. PMID:24209920

  2. Reducing gain shifts in photomultiplier tubes

    DOEpatents

    Cohn, Charles E.

    1976-01-01

    A means is provided for reducing gain shifts in multiplier tubes due to varying event count rates. It includes means for limiting the number of cascaded, active dynodes of the multiplier tube to a predetermined number with the last of predetermined number of dynodes being the output terminal of the tube. This output is applied to an amplifier to make up for the gain sacrificed by not totally utilizing all available active stages of the tube. Further reduction is obtained by illuminating the predetermined number of dynodes with a light source of such intensity that noise appearing at the output dynode associated with the illumination is negligible.

  3. Analytic gain in probabilistic decompression sickness models.

    PubMed

    Howle, Laurens E

    2013-11-01

    Decompression sickness (DCS) is a disease known to be related to inert gas bubble formation originating from gases dissolved in body tissues. Probabilistic DCS models, which employ survival and hazard functions, are optimized by fitting model parameters to experimental dive data. In the work reported here, I develop methods to find the survival function gain parameter analytically, thus removing it from the fitting process. I show that the number of iterations required for model optimization is significantly reduced. The analytic gain method substantially improves the condition number of the Hessian matrix which reduces the model confidence intervals by more than an order of magnitude.

  4. Varactor-diode modulator yields conversion gain

    NASA Astrophysics Data System (ADS)

    Breitkopf, K.

    1980-05-01

    It is shown that varactor diodes used as modulator elements can make a balanced diode mixer yield conversion gain when employed in an upconverter. Replacing the normal mixer diodes with varactor diodes and inserting the IF and LO voltages at a level that drives the diodes into their nonlinear voltage-capacitance region produces a parametric amplifying effect. This modification results in conversion gain rather than loss, and brings the desired output power up to the 0.1-1.0 W level. The use of this technique in a lower-sideband UHF TV upconverter is considered.

  5. Measurement of Information Gain from Written Discourse.

    ERIC Educational Resources Information Center

    Mosberg, Ludwig

    A pretest/post-test procedure for measuring information gain from discourse was investigated together with several other aspects of discourse processing. The main purpose was to determine the effect of a pretest on discourse learning as measured by post-test performance. The study also investigated (1) serial position effects in learning from…

  6. Electromagnetically induced gain in molecular systems

    NASA Astrophysics Data System (ADS)

    Mukherjee, Nandini; Patel, C. Kumar N.

    2009-12-01

    We report electromagnetically induced gain in a highly degenerate two-level rotational vibrational molecular system. Using two photon (Raman-type) interaction with right and left circularly polarized pump and probe waves, the Zeeman coherence is established within the manifold of degenerate sublevels belonging to a rotational vibrational eigenstate. We analytically and numerically calculate the third-order nonlinear optical susceptibility for a Doppler-broadened molecular transition for an arbitrary high rotational angular momentum (J≥20) . It is shown that for a Q -type open transition, a weak probe will experience an electromagnetically induced gain in presence of a strong copropagating pump wave. The inversionless gain originates due to cancellation of absorption from the interference of the coupled Λ - and V-type excitation channels in an N -type configuration. A detailed analysis of the optical susceptibility as a function of Doppler detuning explains how the gain bands are generated in a narrow transparency window from the overlapping contributions of different velocity groups. It is shown that the orientation dependent coherent interaction in presence of a strong pump induces narrow resonances for the probe susceptibility. The locations, intensity, and sign (positive or negative susceptibility) of these resonances are decided by the frequency detuning of the Doppler group and the strength of the coupling field. The availability of high power tunable quantum cascade lasers covering a spectral region from about 4 to 12μm opens up the possibility of investigating the molecular vibrational rotational transitions for a variety of coherent effects.

  7. Project GAIN Evaluation: 1969-70.

    ERIC Educational Resources Information Center

    Biller, Julian

    Project GAIN was designed to meet the special needs of the academically retarded junior high school student. This federally funded project has been on-going in Broward County (Florida) since January 1966. The project was conceived of as a means to motivate and educate those students whose "dull normal" intellectual ability might otherwise doom…

  8. Net Photorefractive Gain In Gallium Arsenide

    NASA Technical Reports Server (NTRS)

    Liu, Tsuen-Hsi; Cheng, Li-Jen

    1990-01-01

    Prerequisite includes applied electric field. Electric field applied to GaAs crystal in which two infrared beams interfere. Depending on quality of sample and experimental conditions, net photorefractive gain obtained. Results offer possibility of new developments in real-time optical processing of signals by use of near-infrared lasers of low power.

  9. X chromosome gain in male breast cancer.

    PubMed

    Di Oto, Enrico; Monti, Valentina; Cucchi, Maria C; Masetti, Riccardo; Varga, Zsuzsanna; Foschini, Maria P

    2015-12-01

    Male breast cancer (MBC) is an uncommon disease whose molecular profile is not well known. X chromosome gain has been described as a marker of aggressive behavior in female breast cancer. The aim of this study is to investigate the role of the X chromosome in male breast cancer. Twenty cases of male breast invasive ductal carcinoma were retrieved and compared with 10 cases of gynecomastia. Cases were tested by fluorescence in situ hybridization to assess a cytogenetic profile for the X chromosome. The X chromosome status was compared with histopathologic features and stage at presentation. All MBC cases harbored an X chromosome gain (100%) in a variable percentage of neoplastic cells, ranging from 31% to 85% (mean, 59%). On the contrary, all cases of gynecomastia showed wild X chromosome asset. The patients' age at surgery and tumor grading showed a statistically significant correlation (P = .0188-.04), with the percentages of neoplastic cells showing an X chromosome gain. These data suggest that this X chromosome gain plays a role in the neoplastic transformation of male breast epithelial cells.

  10. Dimensions of Compliance-Gaining Situations.

    ERIC Educational Resources Information Center

    Cody, Michael J.; And Others

    1983-01-01

    Tested a seven-factor model of situation perception to develop a set of valid and reliable situation perception factors for use in compliance-gaining research. (Factors included personal benefits, intimacy, rights, resistance, dominance, situation apprehension, and relational consequences.) Found that the model fit the data well and was superior…

  11. Pleasure Reading and Reading Rate Gains

    ERIC Educational Resources Information Center

    Beglar, David; Hunt, Alan

    2014-01-01

    This study investigated the effects of (a) the amount of pleasure reading completed, (b) the type of texts read (i.e., simplified or unsimplified books), and (c) the level of simplified texts read by 14 Japanese university students who made the largest reading rate gains over one academic year. The findings indicated that the participants who made…

  12. GAIN Appraisal Program IV. Fourth Report.

    ERIC Educational Resources Information Center

    Simon, June; And Others

    The Greater Avenues for Independence (GAIN) legislation in California mandated a full range of employment-related training and supportive services designed to provide welfare program applicants and recipients with the skills needed to acquire unsubsidized employment through education and training. Tests to assess the basic reading, mathematics,…

  13. Weight Gain Through Self-Control Procedures

    ERIC Educational Resources Information Center

    Gulanick, Nancy; And Others

    1975-01-01

    Underweight subjects were assigned to either a self-reinforcement condition, a self-punishment condition, or to a discussion/reflection control condition. The subjects received one treatment session per week over a five-week period. After treatment, the self-reinforcement groups gained significantly more pounds (kilograms) than either of the other…

  14. Method and system for edge cladding of laser gain media

    SciTech Connect

    Bayramian, Andrew James; Caird, John Allyn; Schaffers, Kathleen Irene

    2014-03-25

    A gain medium operable to amplify light at a gain wavelength and having reduced transverse ASE includes an input surface and an output surface opposing the input surface. The gain medium also includes a central region including gain material and extending between the input surface and the output surface along a longitudinal optical axis of the gain medium. The gain medium further includes an edge cladding region surrounding the central region and extending between the input surface and the output surface along the longitudinal optical axis of the gain medium. The edge cladding region includes the gain material and a dopant operable to absorb light at the gain wavelength.

  15. Stacked Transformer for Driver Gain and Receive Signal Splitting

    NASA Technical Reports Server (NTRS)

    Driscoll, Kevin R.

    2013-01-01

    In a high-speed signal transmission system that uses transformer coupling, there is a need to provide increased transmitted signal strength without adding active components. This invention uses additional transformers to achieve the needed gain. The prior art uses stronger drivers (which require an IC redesign and a higher power supply voltage), or the addition of another active component (which can decrease reliability, increase power consumption, reduce the beneficial effect of serializer/deserializer preemphasis or deemphasis, and/or interfere with fault containment mechanisms), or uses a different transformer winding ratio (which requires redesign of the transformer and may not be feasible with high-speed signals that require a 1:1 winding ratio). This invention achieves the required gain by connecting the secondaries of multiple transformers in series. The primaries of these transformers are currently either connected in parallel or are connected to multiple drivers. There is also a need to split a receive signal to multiple destinations with minimal signal loss. Additional transformers can achieve the split. The prior art uses impedance-matching series resistors that cause a loss of signal. Instead of causing a loss, most instantiations of this invention would actually provide gain. Multiple transformers are used instead of multiple windings on a single transformer because multiple windings on the same transformer would require a redesign of the transformer, and may not be feasible with high-speed transformers that usually require a bifilar winding with a 1:1 ratio. This invention creates the split by connecting the primaries of multiple transformers in series. The secondary of each transformer is connected to one of the intended destinations without the use of impedance-matching series resistors.

  16. Dynamic modulation of visual and electrosensory gains for locomotor control.

    PubMed

    Sutton, Erin E; Demir, Alican; Stamper, Sarah A; Fortune, Eric S; Cowan, Noah J

    2016-05-01

    Animal nervous systems resolve sensory conflict for the control of movement. For example, the glass knifefish, Eigenmannia virescens, relies on visual and electrosensory feedback as it swims to maintain position within a moving refuge. To study how signals from these two parallel sensory streams are used in refuge tracking, we constructed a novel augmented reality apparatus that enables the independent manipulation of visual and electrosensory cues to freely swimming fish (n = 5). We evaluated the linearity of multisensory integration, the change to the relative perceptual weights given to vision and electrosense in relation to sensory salience, and the effect of the magnitude of sensory conflict on sensorimotor gain. First, we found that tracking behaviour obeys superposition of the sensory inputs, suggesting linear sensorimotor integration. In addition, fish rely more on vision when electrosensory salience is reduced, suggesting that fish dynamically alter sensorimotor gains in a manner consistent with Bayesian integration. However, the magnitude of sensory conflict did not significantly affect sensorimotor gain. These studies lay the theoretical and experimental groundwork for future work investigating multisensory control of locomotion. PMID:27170650

  17. [Food additives and healthiness].

    PubMed

    Heinonen, Marina

    2014-01-01

    Additives are used for improving food structure or preventing its spoilage, for example. Many substances used as additives are also naturally present in food. The safety of additives is evaluated according to commonly agreed principles. If high concentrations of an additive cause adverse health effects for humans, a limit of acceptable daily intake (ADI) is set for it. An additive is a risk only when ADI is exceeded. The healthiness of food is measured on the basis of nutrient density and scientifically proven effects.

  18. Sabbatical leave: who gains and how much?

    PubMed

    Davidson, Oranit B; Eden, Dov; Westman, Mina; Cohen-Charash, Yochi; Hammer, Leslie B; Kluger, Avraham N; Krausz, Moshe; Maslach, Christina; O'Driscoll, Michael; Perrewé, Pamela L; Quick, James Campbell; Rosenblatt, Zehava; Spector, Paul E

    2010-09-01

    A rigorous quasi-experiment tested the ameliorative effects of a sabbatical leave, a special case of respite from routine work. We hypothesized that (a) respite increases resource level and well-being and (b) individual differences and respite features moderate respite effects. A sample of 129 faculty members on sabbatical and 129 matched controls completed measures of resource gain, resource loss, and well-being before, during, and after the sabbatical. Among the sabbatees, resource loss declined and resource gain and well-being rose during the sabbatical. The comparison group showed no change. Moderation analysis revealed that those who reported higher respite self-efficacy and greater control, were more detached, had a more positive sabbatical experience, and spent their sabbatical outside their home country enjoyed more enhanced well-being than others.

  19. Voyager high gain antenna calibration and pointing

    NASA Technical Reports Server (NTRS)

    Jahanshahi, M. H.

    1979-01-01

    A mathematical description of the data reduction technique used in analyzing Voyager calibration data is presented. To achieve the required telecommunication link performance, highly accurate pointing of the Voyager high gain antenna boresight relative to earth is necessary. To provide the optimum pointing, in-flight calibrations of the high gain antenna pointing mechanism are regularly made, and the design of the calibration and the antenna error models is delineated. It is shown that due to the use of wide angle sun sensors for celestial attitude control, the Voyager antenna error model differs from those of previous missions. Results of the in-flight calibrations and their implementation in improving the antenna pointing are also presented.

  20. Time ramped gain for borehole televiewer

    SciTech Connect

    Rambow, F.H.K.

    1989-08-08

    This patent describes an improvement in a borehole imaging apparatus wherein a rotating acoustic transducer means is periodically pulsed to emit a sequence of acoustic pulses into the borehole fluid toward the borehole wall and the reflected response of the acoustic pulse is received by the transducer means and converted to a related electrical signal. The improvement comprises: electrical signal compensating means located in the borehole for compensating substantially each of the electrical signals. The compensating means including variable gain amplifier means controllable from the surface for continuing to increase the amount of gain applied to each electrical signal as a function of the propagation time of the acoustic energy through the borehole fluid, to reduce the effects such as initial ringdown, mud reflections, and time-dependent borehole fluid attenuation of the acoustic energy.

  1. Pole placement with constant gain output feedback

    NASA Technical Reports Server (NTRS)

    Sridhar, B.; Lindorff, D. P.

    1972-01-01

    Given a linear time invariant multivariable system with m inputs and p outputs, it was shown that p closed loop poles of the system can be preassigned arbitrarily using constant gain output feedback provided (A circumflex, B circumflex) is controllable. These data show that if (A circumflex, B circumflex, C circumflex) is controllable and observable, and Rank B circumflex = m, Rank C circumflex = p, then max (m,p) poles of the system can be assigned arbitarily using constant gain output feedback. Further, it is shown that in some cases more than max (m,p) poles can be arbitrarily assigned. A least square design technique is outlined to approximate the desired pole locations when it is not possible to place all the poles.

  2. Contrast Gain Control Model Fits Masking Data

    NASA Technical Reports Server (NTRS)

    Watson, Andrew B.; Solomon, Joshua A.; Null, Cynthia H. (Technical Monitor)

    1994-01-01

    We studied the fit of a contrast gain control model to data of Foley (JOSA 1994), consisting of thresholds for a Gabor patch masked by gratings of various orientations, or by compounds of two orientations. Our general model includes models of Foley and Teo & Heeger (IEEE 1994). Our specific model used a bank of Gabor filters with octave bandwidths at 8 orientations. Excitatory and inhibitory nonlinearities were power functions with exponents of 2.4 and 2. Inhibitory pooling was broad in orientation, but narrow in spatial frequency and space. Minkowski pooling used an exponent of 4. All of the data for observer KMF were well fit by the model. We have developed a contrast gain control model that fits masking data. Unlike Foley's, our model accepts images as inputs. Unlike Teo & Heeger's, our model did not require multiple channels for different dynamic ranges.

  3. Directionality switchable gain stabilized linear repeater

    NASA Astrophysics Data System (ADS)

    Ota, Takayuki; Ohmachi, Tadashi; Aida, Kazuo

    2004-10-01

    We propose a new approach to realize a bidirectional linear repeater suitable for future optical internet networks and fault location in repeater chain with OTDR. The proposed approach is the linear repeater of simple configuration whose directionality is rearranged dynamically by electrical control signal. The repeater is composed of a magneto-optical switch, a circulator, a dynamically gain stabilized unidirectional EDFA, and control circuits. The repeater directionality is rearranged as fast as 0.1ms by an electrical control pulse. It is experimentally confirmed that OTDR with the directionality switchable repeater is feasible for repeater chain. The detailed design and performance of the repeater are also discussed, including the multi-pass interference (MPI) which may arise in the proposed repeater, the effect of the MPI on SNR degradation of the repeater chain and the feed-forward EDFA gain control circuit.

  4. The Persistence of Gaining and Losing Streams

    NASA Astrophysics Data System (ADS)

    McNamara, J. P.; Frye, A.

    2012-12-01

    Streams are commonly classified as "gaining" or "losing", according to their relationships with groundwater. However, the gaining and losing nature of a stream can vary in space and time. Understanding the spatial and temporal persistence of gaining and losing reaches is essential for understanding controls on stream health. This is particularly important during low flow conditions. Hydrologic models are typically designed to simulate high flows, and are challenged by low flow. This problem will become more important as hydrologists are asked to forecast the increasing occurrence of low flows as a consequence of climate change. Low flow discharges have been a focus of research as they are occurring earlier in the summer and have longer durations throughout the fall. A concern is how low flow will affect water resources and its users in the region when demand is at its highest. As low flow discharges continue to persist, debate over these rights will continue as well. This study we used chloride as a chemical tracer to monitor gains and losses of stream discharge of small watershed in Southwestern, Idaho. Six conductivity probes were spaced evenly 200m apart along a control reach 1200m in total length. Tracers were performed at least once a month at this site throughout the winter and spring and even more often during the summer dry down to understand the temporal changes occurring. Spatial variations were observed by performing basin wide tracers over a stream length of ~9km during the spring and late summer. Results show that stream baseflow is dependent on the winter snowpack and spring rains in order to recharge the deep groundwater systems and to create a hydrologic connection between the stream and local hillslopes. As a result, when winter snowpack's and spring rains are mild, this connectivity is cut off much sooner producing low flow conditions much earlier in the summer.

  5. Mispredicting the Hedonic Benefits of Segregated Gains

    ERIC Educational Resources Information Center

    Morewedge, Carey K.; Gilbert, Daniel T.; Keysar, Boaz; Berkovits, Michael J.; Wilson, Timothy D.

    2007-01-01

    The hedonic benefit of a gain (e.g., receiving $100) may be increased by segregating it into smaller units that are distributed over time (e.g., receiving $50 on each of 2 days). However, if these units are too small (e.g., receiving 1 cent on each of 10,000 days), they may fall beneath the person's hedonic limen and have no hedonic benefit at…

  6. Optical antenna gain. II - Receiving antennas

    NASA Technical Reports Server (NTRS)

    Degnan, J. J.; Klein, B. J.

    1974-01-01

    Expressions are developed for the gain of a centrally obscured, circular optical antenna used as the collecting and focusing optics in a laser receiver, involving losses due to (1) incoming light blockage by central obscuration, (2) energy spillover at the detector, and (3) the effect of local oscillator distribution in the case of heterodyne or homodyne detection. Numerical results are presented for direct detection and for three types of local oscillator distribution (uniform, Gaussian, and matched).

  7. Gain scaling for multirate filter banks

    SciTech Connect

    Brislawn, Christopher M

    2009-01-01

    Eliminating two trivial degrees of freedom corresponding to the lowpass DC response and the highpass Nyquist response in a two-channel multirate filter bank seems simple enough. Nonetheless, the ISO/IEC JPEG 2000 image coding standard manages to make this mundane task look totally mysterious. We reveal the true meaning behind JPEG 2000's arcane specifications for filter bank normalization and point out how the seemingly trivial matter of gain scaling leads to highly nontrivial issues concerning uniqueness of lifting factorizations.

  8. High gain feedback and telerobotic tracking

    NASA Technical Reports Server (NTRS)

    Koditschek, D. E.

    1987-01-01

    Asymptotically stable linear time invariant systems are capable of tracking arbitrary reference signals with a bounded error proportional to the magnitude of the reference signal (and its derivatives). It is shown that a similar property holds for a general class of nonlinear dynamical systems which includes all robots. As in the linear case, the error bound may be made arbitrarily small by increasing the magnitude of the feedback gains which stabilize the system.

  9. Optical antenna gain. III - The effect of secondary element support struts on transmitter gain

    NASA Technical Reports Server (NTRS)

    Klein, B. J.; Degnan, J. J.

    1976-01-01

    The effect of a secondary-element spider support structure on optical antenna transmitter gain is analyzed. An expression describing the influence of the struts on the axial gain, in both the near and far fields, is derived as a function of the number of struts and their width. It is found that, for typical systems, the struts degrade the on-axis gain by less than 0.4 dB, and the first side-lobe level is not increased significantly. Contour plots have also been included to show the symmetry of the far-field distributions for three- and four-support members.

  10. Loss/gain-induced ultrathin antireflection coatings.

    PubMed

    Luo, Jie; Li, Sucheng; Hou, Bo; Lai, Yun

    2016-01-01

    Tradional antireflection coatings composed of dielectric layers usually require the thickness to be larger than quarter wavelength. Here, we demonstrate that materials with permittivity or permeability dominated by imaginary parts, i.e. lossy or gain media, can realize non-resonant antireflection coatings in deep sub-wavelength scale. Interestingly, while the reflected waves are eliminated as in traditional dielectric antireflection coatings, the transmitted waves can be enhanced or reduced, depending on whether gain or lossy media are applied, respectively. We provide a unified theory for the design of such ultrathin antireflection coatings, showing that under different polarizations and incident angles, different types of ultrathin coatings should be applied. Especially, under transverse magnetic polarization, the requirement shows a switch between gain and lossy media at Brewster angle. As a proof of principle, by using conductive films as a special type of lossy antireflection coatings, we experimentally demonstrate the suppression of Fabry-Pérot resonances in a broad frequency range for microwaves. This valuable functionality can be applied to remove undesired resonant effects, such as the frequency-dependent side lobes induced by resonances in dielectric coverings of antennas. Our work provides a guide for the design of ultrathin antireflection coatings as well as their applications in broadband reflectionless devices. PMID:27349750

  11. [Pattern of wight gain during normal pregnancy].

    PubMed

    Velazco Orellana, R; Alvarez Aguilar, C; Mejía Rodríguez, O

    1998-03-01

    The maternal weight gain during pregnancy has been established as a common acceptance criterion about 11 Kg., and its evaluation is of interest in Gynecology and Obstetrics; the objective of this study was to evaluate the Gestational Weight Gain Pattern (GWGP) during the normal pregnancy and its association with the maternal height, pregestional weight, Body Mass Index (BMI) schooling, the intergensic interval and the newborn weight. It was found through a longitudinal and prospective study in women of the urban area, under prenatal control in the Instituto Mexicano del Seguro Social (IMSS), in Morelia, Mich. México, that the average overall GWGP was of 9.3 Kg, and a normality band within 6.6 to 12 Kg which is smaller than the established by obstetrics criteria. It was not found a correlation between the GWGP and the newborn weight, now that the 94.3% of them had normal weight. The mother's age, weight, body mass index and schooling didn't show any correlation with the maternal weight gain during the pregnancy. It was shown that the mother's height and parity influence notably the GWGP. It's convenient the adoption during the prenatal control to determine that the GWGP normality is in agreement with the bio-psycho-social characteristics of the Mexican woman.

  12. Loss/gain-induced ultrathin antireflection coatings

    PubMed Central

    Luo, Jie; Li, Sucheng; Hou, Bo; Lai, Yun

    2016-01-01

    Tradional antireflection coatings composed of dielectric layers usually require the thickness to be larger than quarter wavelength. Here, we demonstrate that materials with permittivity or permeability dominated by imaginary parts, i.e. lossy or gain media, can realize non-resonant antireflection coatings in deep sub-wavelength scale. Interestingly, while the reflected waves are eliminated as in traditional dielectric antireflection coatings, the transmitted waves can be enhanced or reduced, depending on whether gain or lossy media are applied, respectively. We provide a unified theory for the design of such ultrathin antireflection coatings, showing that under different polarizations and incident angles, different types of ultrathin coatings should be applied. Especially, under transverse magnetic polarization, the requirement shows a switch between gain and lossy media at Brewster angle. As a proof of principle, by using conductive films as a special type of lossy antireflection coatings, we experimentally demonstrate the suppression of Fabry-Pérot resonances in a broad frequency range for microwaves. This valuable functionality can be applied to remove undesired resonant effects, such as the frequency-dependent side lobes induced by resonances in dielectric coverings of antennas. Our work provides a guide for the design of ultrathin antireflection coatings as well as their applications in broadband reflectionless devices. PMID:27349750

  13. Raman gains of ADP and KDP crystals

    NASA Astrophysics Data System (ADS)

    Zhou, Hai-Liang; Zhang, Qing-Hua; Wang, Bo; Xu, Xin-Guang; Wang, Zheng-Ping; Sun, Xun; Zhang, Fang; Zhang, Li-Song; Liu, Bao-An; Chai, Xiang-Xu

    2015-04-01

    In this paper, the Raman gain coefficients of ammonium dihydrogen phosphate (ADP) and potassium dihydrogen phosphate (KDP) crystals are measured. By using a pump source of a 30-ps, 532-nm laser, the gain coefficients of ADP and KDP are 1.22 cm/GW, and 0.91 cm/GW, respectively. While for a 20-ps, 355-nm pump laser, the gain coefficients of these two crystals are similar, which are 1.95 cm/GW for ADP and 1.86 for KDP. The present results indicate that for ultra-violet frequency conversion, the problem of stimulated Raman scattering for ADP crystal will not be more serious than that for KDP crystal. Considering other advantages such the larger nonlinear optical coefficient, higher laser damage threshold, and lower noncritical phase-matching temperature, it can be anticipated that ADP will be a powerful competitor to KDP in large aperture, high energy third-harmonic generation or fourth-harmonic generation applications. Project supported by the National Natural Science Foundation of China (Grant Nos. 51323002 and 51402173), the Independent Innovation Foundation of Shandong University, China (Grant Nos. IIFSDU and 2012JC016), the Program for New Century Excellent Talents in University, China (Grant No. NCET-10-0552), the Fund from the Key Laboratory of Neutron Physics, China Academy of Engineering Physics (Grant No. 2014BB07), and the Natural Science Foundation for Distinguished Young Scholar of Shandong Province, China (Grant No. JQ201218).

  14. Comparative analysis of the intrinsic voltage gain and unit gain frequency between SOI and bulk FinFETs up to high temperatures

    NASA Astrophysics Data System (ADS)

    Oliveira, Alberto Vinicius de; Agopian, Paula Ghedini Der; Martino, Joao Antonio; Simoen, Eddy; Claeys, Cor; Collaert, Nadine; Thean, Aaron

    2016-09-01

    This paper presents an experimental analysis of the analog application figures of merit: the intrinsic voltage gain (AV) and unit gain frequency, focusing on the performance comparison between silicon triple gate pFinFET devices, which were processed on both Si and Silicon-On-Insulator (SOI) substrates. The high temperature (from 25 °C to 150 °C) influence and different channel lengths and fin widths were also taken into account. While the temperature impact on the intrinsic voltage gain (AV) is limited, the unit gain frequency was strongly affected due to the carrier mobility degradation at higher temperatures, for both p- and n-type FinFET structures. In addition, the pFinFETs showed slightly larger AV values compared to the n-type counterparts, whereby the bulk FinFETs presented a higher dispersion than the SOI FinFETs.

  15. Sympathetic baroreflex gain in normotensive pregnant women

    PubMed Central

    Usselman, Charlotte W.; Skow, Rachel J.; Matenchuk, Brittany A.; Chari, Radha S.; Julian, Colleen G.; Stickland, Michael K.; Davenport, Margie H.

    2015-01-01

    Muscle sympathetic nerve activity is increased during normotensive pregnancy while mean arterial pressure is maintained or reduced, suggesting baroreflex resetting. We hypothesized spontaneous sympathetic baroreflex gain would be reduced in normotensive pregnant women relative to nonpregnant matched controls. Integrated muscle sympathetic burst incidence and total sympathetic activity (microneurography), blood pressure (Finometer), and R-R interval (ECG) were assessed at rest in 11 pregnant women (33 ± 1 wk gestation, 31 ± 1 yr, prepregnancy BMI: 23.5 ± 0.9 kg/m2) and 11 nonpregnant controls (29 ± 1 yr; BMI: 25.2 ± 1.7 kg/m2). Pregnant women had elevated baseline sympathetic burst incidence (43 ± 2 vs. 33 ± 2 bursts/100 heart beats, P = 0.01) and total sympathetic activity (1,811 ± 148 vs. 1,140 ± 55 au, P < 0.01) relative to controls. Both mean (88 ± 3 vs. 91 ± 2 mmHg, P = 0.4) and diastolic (DBP) (72 ± 3 vs. 73 ± 2 mmHg, P = 0.7) pressures were similar between pregnant and nonpregnant women, respectively, indicating an upward resetting of the baroreflex set point with pregnancy. Baroreflex gain, calculated as the linear relationship between sympathetic burst incidence and DBP, was reduced in pregnant women relative to controls (−3.7 ± 0.5 vs. −5.4 ± 0.5 bursts·100 heart beats−1·mmHg−1, P = 0.03), as was baroreflex gain calculated with total sympathetic activity (−294 ± 24 vs. −210 ± 24 au·100 heart beats−1·mmHg−1; P = 0.03). Cardiovagal baroreflex gain (sequence method) was not different between nonpregnant controls and pregnant women (49 ± 8 vs. 36 ± 8 ms/mmHg; P = 0.2). However, sympathetic (burst incidence) and cardiovagal gains were negatively correlated in pregnant women (R = −0.7; P = 0.02). Together, these data indicate that the influence of the sympathetic nervous system over arterial blood pressure is reduced in normotensive pregnancy, in terms of both long-term and beat-to-beat regulation of arterial pressure

  16. Maintenance of gains following experiential therapies for depression.

    PubMed

    Ellison, Jennifer A; Greenberg, Leslie S; Goldman, Rhonda N; Angus, Lynne

    2009-02-01

    Follow-up data across an 18-month period are presented for 43 adults who had been randomly assigned and had responded to short-term client-centered (CC) and emotion-focused (EFT) therapies for major depression. Long-term effects of these short-term therapies were evaluated using relapse rates, number of asymptomatic or minimally symptomatic weeks, survival times across an 18-month follow-up, and group comparisons on self-report indices at 6- and 18-month follow-up among those clients who responded to the acute treatment phase. EFT treatment showed superior effects across 18 months in terms of less depressive relapse and greater number of asymptomatic or minimally symptomatic weeks, and the probability of maintaining treatment gains was significantly more likely in the EFT treatment than in the CC treatment. In addition, follow-up self-report results demonstrated significantly greater effects for EFT clients on reduction of depression and improvement of self-esteem, and there were trends in favor of EFT, in comparison with CC, on reduction of general symptom distress and interpersonal problems. Maintenance of treatment gains following an empathic relational treatment appears to be enhanced by the addition of specific experiential and gestalt-derived emotion-focused interventions. Clinical and theoretical implications of these findings are presented. PMID:19170457

  17. Theory of noise in high-gain surface plasmon-polariton amplifiers incorporating dipolar gain media.

    PubMed

    De Leon, Israel; Berini, Pierre

    2011-10-10

    A theoretical analysis of noise in high-gain surface plasmon-polariton amplifiers incorporating dipolar gain media is presented. An expression for the noise figure is obtained in terms of the spontaneous emission rate into the amplified surface plasmon-polariton taking into account the different energy decay channels experienced by dipoles in close proximity to the metallic surface. Two amplifier structures are examined: a single-interface between a metal and a gain medium and a thin metal film bounded by identical gain media on both sides. A realistic configuration is considered where the surface plasmon-polariton undergoing amplification has a Gaussian field profile in the plane of the metal and paraxial propagation along the amplifier's length. The noise figure of these plasmonic amplifiers is studied considering three prototypical gain media with different permittivities. It is shown that the noise figure exhibits a strong dependance on the real part of the permittivities of the metal and gain medium, and that its minimum value is 4/π(∼3.53 dB). The origin of this minimum value is discussed. It is also shown that amplifier configurations supporting strongly confined surface plasmon-polaritons suffer from a large noise figure, which follows from an enhanced spontaneous emission rate due to the Purcell effect.

  18. Gain and frequency tuning within the mouse cochlear apex

    SciTech Connect

    Oghalai, John S.; Raphael, Patrick D.; Gao, Simon; Lee, Hee Yoon; Groves, Andrew K.; Zuo, Jian; Applegate, Brian E.

    2015-12-31

    Normal mammalian hearing requires cochlear outer hair cell active processes that amplify the traveling wave with high gain and sharp tuning, termed cochlear amplification. We have used optical coherence tomography to study cochlear amplification within the apical turn of the mouse cochlea. We measured not only classical basilar membrane vibratory tuning curves but also vibratory responses from the rest of the tissues that compose the organ of Corti. Basilar membrane tuning was sharp in live mice and broad in dead mice, whereas other regions of the organ of Corti demonstrated phase shifts consistent with additional filtering beyond that provided by basilar membrane mechanics. We use these experimental data to support a conceptual framework of how cochlear amplification is tuned within the mouse cochlear apex. We will also study transgenic mice with targeted mutations that affect different biomechanical aspects of the organ of Corti in an effort to localize the underlying processes that produce this additional filtering.

  19. Gain and frequency tuning within the mouse cochlear apex

    NASA Astrophysics Data System (ADS)

    Oghalai, John S.; Gao, Simon; Lee, Hee Yoon; Raphael, Patrick D.; Groves, Andrew K.; Zuo, Jian; Applegate, Brian E.

    2015-12-01

    Normal mammalian hearing requires cochlear outer hair cell active processes that amplify the traveling wave with high gain and sharp tuning, termed cochlear amplification. We have used optical coherence tomography to study cochlear amplification within the apical turn of the mouse cochlea. We measured not only classical basilar membrane vibratory tuning curves but also vibratory responses from the rest of the tissues that compose the organ of Corti. Basilar membrane tuning was sharp in live mice and broad in dead mice, whereas other regions of the organ of Corti demonstrated phase shifts consistent with additional filtering beyond that provided by basilar membrane mechanics. We use these experimental data to support a conceptual framework of how cochlear amplification is tuned within the mouse cochlear apex. We will also study transgenic mice with targeted mutations that affect different biomechanical aspects of the organ of Corti in an effort to localize the underlying processes that produce this additional filtering.

  20. Gain-controlled erbium-doped fiber amplifier using mode-selective photonic lantern

    NASA Astrophysics Data System (ADS)

    Lopez-Galmiche, G.; Sanjabi Eznaveh, Z.; Antonio-Lopez, J. E.; Velazquez-Benitez, A. M.; Rodriguez-Asomoza, J.; Herrera-Piad, L. A.; Sanchez-Mondragon, J. J.; Gonent, C.; Sillard, P.; Li, G.; SchuÌlzgen, A.; Okonkwo, C.; Amezcua Correa, R.

    2016-02-01

    For the first time, we demonstrate the implementation of a core pumped few mode erbium amplifier utilizing a mode selective photonic lantern for spatial modal control of the pump light. This device is able to individually amplify the first six fiber modes with low differential modal gain. In addition, we obtained differential modal gain lower than 1 dB and signal gain of approximately 16.17 dB at λs = 1550 nm through forward pumping the LP21 modes at λp = 976 nm.

  1. Gain results for low voltage FEL

    SciTech Connect

    Shaw, A.; Stuart, R.A.; Al-Shamma`a, A.

    1995-12-31

    We have designed and constructed a low voltage (130 kV) FEL system capable of operating in the microwave frequency range for which the electron beam current is cw (rather than pulsed) in time at a level of {approximately} 12 mA. The gain of this system has been measured as a function of the electron beam accelerating voltage and current level, and the input microwave frequency (8-10 GHz). The results are compared with the predictions of a simple theoretical model.

  2. Semiconductor radiation detector with internal gain

    DOEpatents

    Iwanczyk, Jan; Patt, Bradley E.; Vilkelis, Gintas

    2003-04-01

    An avalanche drift photodetector (ADP) incorporates extremely low capacitance of a silicon drift photodetector (SDP) and internal gain that mitigates the surface leakage current noise of an avalanche photodetector (APD). The ADP can be coupled with scintillators such as CsI(Tl), NaI(Tl), LSO or others to form large volume scintillation type gamma ray detectors for gamma ray spectroscopy, photon counting, gamma ray counting, etc. Arrays of the ADPs can be used to replace the photomultiplier tubes (PMTs) used in conjunction with scintillation crystals in conventional gamma cameras for nuclear medical imaging.

  3. Galileo spacecraft high gain antenna offset calibration

    NASA Technical Reports Server (NTRS)

    Hayati, S. A.

    1982-01-01

    A mathematical model for the estimation of the dual-spin Galileo spacecraft high gain antenna misalignment is developed. The feasibility of the proposed technique is investigated by means of a simulation study. In-flight parameter estimation requires the development of a stochastic model of the spacecraft rotational biases and the earth-received signal strength measurements. The signal strength measurements for X-band frequency are used as observations to estimate the rotational biases and their corresponding uncertainties. The simulation study shows that the initial ground measured uncertainties of .6 mrad can be reduced by a factor of ten.

  4. Turbocharger with downstream pressure-gain combustor

    SciTech Connect

    Sherikar, S.V.

    1991-05-14

    This patent describes a turbocharger. It comprises: an internal combustion engine; a compressor located upstream of the internal combustion engine for increasing the inlet pressure of the internal combustion engine; a turbine located down stream of the internal combustion engine and mechanically coupled to the compressor for driving the compressor; and a pressure-gain combustor located downstream of the turbine for decreasing the outlet pressure of the internal combustion engineer and thus increasing the turbine power output and improving the starting characteristics of the turbocharger.

  5. Gain dynamics in liquid crystal photorefractive hybrids

    NASA Astrophysics Data System (ADS)

    Liebig, C. M.; Tabiryan, N. V.; Basun, S. A.; Ighodalo, I. U.; Reshetnyak, V. Y.; Evans, D. R.

    2014-09-01

    Photorefractive (PR) hybrid liquid crystal (LC) cells have combined the space-charge field generated in either a polymer (using e.g. PVK;C60) with the large birefringence from a LC layer to generate PR grating for beam coupling applications. The efficiency of PR beam coupling in hybrid devices is dependent on the amplitude of the space-charge field, as well as the ability of the LC molecules to align with the corresponding field. In this paper the time dynamics of the formation of the PR gratings are measured in LC hybrid systems and are used to explain the large variation of gain coefficients found in the literature.

  6. Gain measurements at 182 /angstrom/ in C VI generated by a Nd/glass laser

    SciTech Connect

    Kim, D.; Skinner, C.H.; Umesh, G.; Suckewer, S.

    1988-11-01

    We present recent gain measurements in C VI at 182 A for a soft x-ray amplifier produced by a line-focused glass laser(1.053 ..mu..m) on a solid carbon target. The maximum gain measured was 8 +- 1 cm/sup /minus/1/ in the recombining plasma column with additional radiation cooling by iron impurities. 10 refs., 3 figs.

  7. Development of the Exercise Motives and Gains Inventory

    ERIC Educational Resources Information Center

    Strömmer, Sofia T.; Ingledew, David K.; Markland, David

    2015-01-01

    There are existing measures of exercise motives (what people want from exercise), but corresponding measures of gains (what people get) are needed, because motives and gains could influence each other and together influence other variables. An exercise motives and gains inventory (EMGI) was developed by creating gains scales to complement existing…

  8. 26 CFR 1.1202-1 - Deduction for capital gains.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 11 2010-04-01 2010-04-01 true Deduction for capital gains. 1.1202-1 Section 1... (CONTINUED) INCOME TAXES Wash Sales of Stock Or Securities § 1.1202-1 Deduction for capital gains. (a) In computing gross income, adjusted gross income, taxable income, capital gain net income (net capital gain...

  9. IQ Gains in Argentina between 1964 and 1998

    ERIC Educational Resources Information Center

    Flynn, James R.; Rossi-Case, Lilia

    2012-01-01

    The literature on IQ gains in Latin America is sparse. We estimate gains on Raven's Progressive Matrices in the city of La Plata (Argentina) between 1964 and 1998. The gains are robust at the top of the curve as well as at the bottom. Therefore, they are contrary to the hypothesis that nutrition played a major role in recent Argentine IQ gains.…

  10. Estimating the willingness to pay for a quality-adjusted life year in Thailand: does the context of health gain matter?

    PubMed Central

    Thavorncharoensap, Montarat; Teerawattananon, Yot; Natanant, Sirin; Kulpeng, Wantanee; Yothasamut, Jomkwan; Werayingyong, Pitsaphun

    2013-01-01

    Background This study aims to elicit the value of the willingness to pay (WTP) for a quality-adjusted life year (QALY) and to examine the factors associated with the WTP for a QALY (WTP/QALY) value under the Thai health care setting. Methods A community-based survey was conducted among 1191 randomly selected respondents. Each respondent was interviewed face-to-face to elicit his/her health state preference in each of three pairs of health conditions: (1) unilateral and bilateral blindness, (2) paraplegia and quadriplegia, and (3) mild and moderate allergies. A visual analog scale (VAS) and time trade off (TTO) were used as the eliciting methods. Subsequently, the respondents were asked about their WTP for the treatment and prevention of each pair of health conditions by using a bidding-game technique. Results With regards to treatment, the mean WTP for a QALY value (WTP/QALYtreatment) estimated by the TTO method ranged from 59,000 to 285,000 baht (16.49 baht = US$1 purchasing power parity [PPP]). In contrast, the mean WTP for a QALY value in terms of prevention (WTP/QALYprevention) was significantly lower, ranging from 26,000 to 137,000 baht. Gender, household income, and hypothetical scenarios were also significant factors associated with the WTP/QALY values. Conclusion The WTP/QALY values elicited in this study were approximately 0.4 to 2 times Thailand’s 2008 GDP per capita. These values were in line with previous studies conducted in several different settings. This study’s findings clearly support the opinion that a single ceiling threshold should not be used for the resource allocation of all types of interventions. PMID:23345984

  11. Weight gain prevention in young adults: design of the study of novel approaches to weight gain prevention (SNAP) randomized controlled trial

    PubMed Central

    2013-01-01

    Background Weight gain during young adulthood is common and is associated with increased cardiovascular risk. Preventing this weight gain from occurring may be critical to improving long-term health. Few studies have focused on weight gain prevention, and these studies have had limited success. SNAP (Study of Novel Approaches to Weight Gain Prevention) is an NIH-funded randomized clinical trial examining the efficacy of two novel self-regulation approaches to weight gain prevention in young adults compared to a minimal treatment control. The interventions focus on either small, consistent changes in eating and exercise behaviors, or larger, periodic changes to buffer against expected weight gains. Methods/Design SNAP targets recruitment of six hundred young adults (18–35 years) with a body mass index between 21.0-30.0 kg/m2, who will be randomly assigned with equal probability to: (1) minimal intervention control; (2) self-regulation with Small Changes; or (3) self-regulation with Large Changes. Both interventions receive 8 weekly face-to-face group sessions, followed by 2 monthly sessions, with two 4-week refresher courses in each of subsequent years. Participants are instructed to report weight via web at least monthly thereafter, and receive monthly email feedback. Participants in Small Changes are taught to make small daily changes (~100 calorie changes) in how much or what they eat and to accumulate 2000 additional steps per day. Participants in Large Changes are taught to create a weight loss buffer of 5–10 pounds once per year to protect against anticipated weight gains. Both groups are encouraged to self-weigh daily and taught a self-regulation color zone system that specifies action depending on weight gain prevention success. Individualized treatment contact is offered to participants who report weight gains. Participants are assessed at baseline, 4 months, and then annually. The primary outcome is weight gain over an average of 3 years of follow

  12. Polyimide processing additives

    NASA Technical Reports Server (NTRS)

    Fletcher, James C. (Inventor); Pratt, J. Richard (Inventor); St.clair, Terry L. (Inventor); Stoakley, Diane M. (Inventor); Burks, Harold D. (Inventor)

    1992-01-01

    A process for preparing polyimides having enhanced melt flow properties is described. The process consists of heating a mixture of a high molecular weight poly-(amic acid) or polyimide with a low molecular weight amic acid or imide additive in the range of 0.05 to 15 percent by weight of additive. The polyimide powders so obtained show improved processability, as evidenced by lower melt viscosity by capillary rheometry. Likewise, films prepared from mixtures of polymers with additives show improved processability with earlier onset of stretching by TMA.

  13. Polyimide processing additives

    NASA Technical Reports Server (NTRS)

    Pratt, J. Richard (Inventor); St.clair, Terry L. (Inventor); Stoakley, Diane M. (Inventor); Burks, Harold D. (Inventor)

    1993-01-01

    A process for preparing polyimides having enhanced melt flow properties is described. The process consists of heating a mixture of a high molecular weight poly-(amic acid) or polyimide with a low molecular weight amic acid or imide additive in the range of 0.05 to 15 percent by weight of the additive. The polyimide powders so obtained show improved processability, as evidenced by lower melt viscosity by capillary rheometry. Likewise, films prepared from mixtures of polymers with additives show improved processability with earlier onset of stretching by TMA.

  14. Brain Gain am Beispiel Österreich

    NASA Astrophysics Data System (ADS)

    Aschbacher, Christine; Gejguš, Mirko; Sablik, Jozef

    2016-06-01

    BrainGain is a common trend within the last ten years in Europe and all-over the world. Managers, key players and scientists are allowed to choose wherever they want to work in the world. As there is a lack of qualified individuals for companies and universities, BrainGain has become a necessity, and mostly - the higher educated individuals are moving away according to a better offer elsewhere in the world. Therefore, a lot of expats are moving around with their families. Many times, the lack of integration at the current place, country or city, is the critical success factor for staying or leaving. Furthermore, if the family does not feel happy in the current location, then the manager or scientist will move away or return home and the investment will be lost. Moreover, many students have received a good education in a state university, however afterwards they have not secured a satisfactory job in the country where they have studied, therefore they are moving away to utilise their know-how. Measures to retain the know-how include a common placement and a welcome-culture in the country, and also exchanges on an international level.

  15. Giant Raman gain in silicon nanocrystals

    PubMed Central

    Sirleto, Luigi; Antonietta Ferrara, Maria; Nikitin, Timur; Novikov, Sergei; Khriachtchev, Leonid

    2012-01-01

    Nanostructured silicon has generated a lot of interest in the past decades as a key material for silicon-based photonics. The low absorption coefficient makes silicon nanocrystals attractive as an active medium in waveguide structures, and their third-order nonlinear optical properties are crucial for the development of next generation nonlinear photonic devices. Here we report the first observation of stimulated Raman scattering in silicon nanocrystals embedded in a silica matrix under non-resonant excitation at infrared wavelengths (~1.5 μm). Raman gain is directly measured as a function of the silicon content. A giant Raman gain from the silicon nanocrystals is obtained that is up to four orders of magnitude greater than in crystalline silicon. These results demonstrate the first Raman amplifier based on silicon nanocrystals in a silica matrix, thus opening new perspectives for the realization of more efficient Raman lasers with ultra-small sizes, which would increase the synergy between electronic and photonic devices. PMID:23187620

  16. Risk Insights Gained from Fire Incidents

    SciTech Connect

    Kazarians, Mardy; Nowlen, Steven P.

    1999-06-10

    There now exist close to 20 years of history in the application of Probabilistic Risk Assessment (PRA) for the analysis of fire risk at nuclear power plants. The current methods are based on various assumptions regarding fire phenomena, the impact of fire on equipment and operator response, and the overall progression of a fire event from initiation through final resolution. Over this same time period, a number of significant fire incidents have occurred at nuclear power plants around the world. Insights gained from US experience have been used in US studies as the statistical basis for establishing fire initiation frequencies both as a function of the plant area and the initiating fire source.To a lesser extent, the fire experience has also been used to assess the general severity and duration of fires. However, aside from these statistical analyses, the incidents have rarely been scrutinized in detail to verify the underlying assumptions of fire PRAs. This paper discusses an effort, under which a set of fire incidents are being reviewed in order to gain insights directly relevant to the methods, data, and assumptions that form the basis for current fire PRAs. The paper focuses on the objectives of the effort, the specific fire events being reviews methodology, and anticipated follow-on activities.

  17. Gain control in the sonar of odontocetes.

    PubMed

    Ya Supin, Alexander; Nachtigall, Paul E

    2013-06-01

    The sonar of odontocetes processes echo-signals within a wide range of echo levels. The level of echoes varies widely by tens of decibels depending on the level of the emitted sonar pulse, the target strength, the distance to the target, and the sound absorption by the water media. The auditory system of odontocetes must be capable of effective perception, analysis, and discrimination of echo-signals within all this variability. The sonar of odontocetes has several mechanisms to compensate for the echo-level variation (gain control). To date, several mechanisms of the biosonar gain control have been revealed in odontocetes: (1) adjustment of emitted sonar pulse levels (the longer the distance to the target, the higher the level of the emitted pulse), (2) short-term variation of hearing sensitivity based on forward masking of the echo by the preceding self-heard emitted pulse and subsequent release from the masking, and (3) active long-term control of hearing sensitivity. Recent investigations with the use of the auditory evoked-potential technique have demonstrated that these mechanisms effectively minimize the variation of the response to the echo when either the emitted sonar pulse level, or the target distance, or both vary within a wide range. A short review of these data is presented herein.

  18. Compensated gain control circuit for buck regulator command charge circuit

    DOEpatents

    Barrett, D.M.

    1996-11-05

    A buck regulator command charge circuit includes a compensated-gain control signal for compensating for changes in the component values in order to achieve optimal voltage regulation. The compensated-gain control circuit includes an automatic-gain control circuit for generating a variable-gain control signal. The automatic-gain control circuit is formed of a precision rectifier circuit, a filter network, an error amplifier, and an integrator circuit. 5 figs.

  19. Compensated gain control circuit for buck regulator command charge circuit

    DOEpatents

    Barrett, David M.

    1996-01-01

    A buck regulator command charge circuit includes a compensated-gain control signal for compensating for changes in the component values in order to achieve optimal voltage regulation. The compensated-gain control circuit includes an automatic-gain control circuit for generating a variable-gain control signal. The automatic-gain control circuit is formed of a precision rectifier circuit, a filter network, an error amplifier, and an integrator circuit.

  20. Additional Types of Neuropathy

    MedlinePlus

    ... A A Listen En Español Additional Types of Neuropathy Charcot's Joint Charcot's Joint, also called neuropathic arthropathy, ... can stop bone destruction and aid healing. Cranial Neuropathy Cranial neuropathy affects the 12 pairs of nerves ...

  1. Food Additives and Hyperkinesis

    ERIC Educational Resources Information Center

    Wender, Ester H.

    1977-01-01

    The hypothesis that food additives are causally associated with hyperkinesis and learning disabilities in children is reviewed, and available data are summarized. Available from: American Medical Association 535 North Dearborn Street Chicago, Illinois 60610. (JG)

  2. Smog control fuel additives

    SciTech Connect

    Lundby, W.

    1993-06-29

    A method is described of controlling, reducing or eliminating, ozone and related smog resulting from photochemical reactions between ozone and automotive or industrial gases comprising the addition of iodine or compounds of iodine to hydrocarbon-base fuels prior to or during combustion in an amount of about 1 part iodine per 240 to 10,000,000 parts fuel, by weight, to be accomplished by: (a) the addition of these inhibitors during or after the refining or manufacturing process of liquid fuels; (b) the production of these inhibitors for addition into fuel tanks, such as automotive or industrial tanks; or (c) the addition of these inhibitors into combustion chambers of equipment utilizing solid fuels for the purpose of reducing ozone.

  3. Additive Manufacturing Infrared Inspection

    NASA Technical Reports Server (NTRS)

    Gaddy, Darrell

    2014-01-01

    Additive manufacturing is a rapid prototyping technology that allows parts to be built in a series of thin layers from plastic, ceramics, and metallics. Metallic additive manufacturing is an emerging form of rapid prototyping that allows complex structures to be built using various metallic powders. Significant time and cost savings have also been observed using the metallic additive manufacturing compared with traditional techniques. Development of the metallic additive manufacturing technology has advanced significantly over the last decade, although many of the techniques to inspect parts made from these processes have not advanced significantly or have limitations. Several external geometry inspection techniques exist such as Coordinate Measurement Machines (CMM), Laser Scanners, Structured Light Scanning Systems, or even traditional calipers and gages. All of the aforementioned techniques are limited to external geometry and contours or must use a contact probe to inspect limited internal dimensions. This presentation will document the development of a process for real-time dimensional inspection technique and digital quality record of the additive manufacturing process using Infrared camera imaging and processing techniques.

  4. Cost-Effectiveness of Intraarterial Treatment as an Adjunct to Intravenous Tissue Plasminogen Activator for Acute Ischemic Stroke

    PubMed Central

    Leppert, Michelle H; Campbell, Jonathan D; Simpson, Jennifer R; Burke, James F

    2015-01-01

    Background and Purpose The objective of this study was to determine the cost-effectiveness of intraarterial treatment within the 0- to 6- hour window after intravenous (IV) tissue plasminogen activator (tPA) within 0- to 4.5-hours compared to IV tPA alone, in the US setting and from a social perspective. Methods A decision analytic model estimated the lifetime costs and outcomes associated with the additional benefit of intraarterial therapy compared to standard treatment with IV tPA alone. Model inputs were obtained from published literature, the MR CLEAN study, and claims databases in the United States. Health outcomes were measured in quality adjusted life years (QALYs). Treatment benefit was assessed by calculating the cost per QALY gained. One-way and probabilistic sensitivity analyses were performed to estimate the overall uncertainty of model results. Results The addition of intraarterial therapy compared with standard treatment alone yielded a lifetime gain of 0.7 QALY for an additional cost of $9,911, which resulted in a cost of $14,137 per QALY. Multivariable sensitivity analysis predicted cost-effectiveness (≤$50,000 per QALY) in 97.6% of simulation runs. Conclusion Intraarterial treatment after IV tPA for patients with anterior circulation strokes within the 6 hour window is likely cost effective. From a societal perspective, increased investment in access to intraarterial treatment for acute stroke may be justified. PMID:26012639

  5. Phenylethynyl Containing Reactive Additives

    NASA Technical Reports Server (NTRS)

    Connell, John W. (Inventor); Smith, Joseph G., Jr. (Inventor); Hergenrother, Paul M. (Inventor)

    2002-01-01

    Phenylethynyl containing reactive additives were prepared from aromatic diamine, containing phenylethvnvl groups and various ratios of phthalic anhydride and 4-phenylethynviphthalic anhydride in glacial acetic acid to form the imide in one step or in N-methyl-2-pvrrolidinone to form the amide acid intermediate. The reactive additives were mixed in various amounts (10% to 90%) with oligomers containing either terminal or pendent phenylethynyl groups (or both) to reduce the melt viscosity and thereby enhance processability. Upon thermal cure, the additives react and become chemically incorporated into the matrix and effect an increase in crosslink density relative to that of the host resin. This resultant increase in crosslink density has advantageous consequences on the cured resin properties such as higher glass transition temperature and higher modulus as compared to that of the host resin.

  6. Potential impact of legislation mandating breast density notification: benefits, harms, and cost effectiveness of supplemental ultrasound screening

    PubMed Central

    Sprague, Brian L.; Stout, Natasha K.; Schechter, Clyde; van Ravesteyn, Nicolien T.; Cevik, Mucahit; Alagoz, Oguzhan; Lee, Christoph I.; van den Broek, Jeroen J.; Miglioretti, Diana L.; Mandelblatt, Jeanne S.; de Koning, Harry J.; Kerlikowske, Karla; Lehman, Constance D.; Tosteson, Anna N. A.

    2014-01-01

    Background At least nineteen states have laws that require telling women with dense breasts and a negative screening mammogram to consider supplemental screening. The most readily available supplemental screening modality is ultrasound, yet little is known about its effectiveness. Objective To evaluate the benefits, harms, and cost-effectiveness of supplemental ultrasound screening for women with dense breasts. Design Comparative modeling with 3 validated simulation models. Data Sources Surveillance, Epidemiology, and End Results Program; Breast Cancer Surveillance Consortium; the medical literature. Target Population A contemporary cohort of women eligible for routine screening. Time Horizon Lifetime. Perspective Payer. Interventions Supplemental ultrasound screening for women with dense breasts following a negative screening mammogram. Outcome Measures Breast cancer deaths averted, quality-adjusted life years (QALYs) gained, false positive ultrasound biopsy recommendations, costs, costs per QALY gained. Results of Base-Case Analysis Supplemental ultrasound screening after a negative mammogram for women aged 50–74 with heterogeneously or extremely dense breasts averted 0.36 additional breast cancer deaths (range across models: 0.14–0.75), gained 1.7 QALYs (0.9–4.7), and resulted in 354 false-positive ultrasound biopsy recommendations (345–421) per 1000 women with dense breasts compared with biennial screening by mammography alone. The cost-effectiveness ratio was $325,000 per QALY gained ($112,000-$766,000). Restricting supplemental ultrasound screening to women with extremely dense breasts cost $246,000 per QALY gained ($74,000-$535,000). Results of Sensitivity Analysis The conclusions were not sensitive to ultrasound performance characteristics, screening frequency, or starting age. Limitations Provider costs for coordinating supplemental ultrasound were not considered. Conclusions Supplemental ultrasound screening for women with dense breasts undergoing

  7. Ribose Accelerates Gut Motility and Suppresses Mouse Body Weight Gaining

    PubMed Central

    Liu, Yan; Li, Tong-Ruei R; Xu, Cong; Xu, Tian

    2016-01-01

    The increasing prevalence of obesity is closely related to excessive energy consumption. Clinical intervention of energy intake is an attractive strategy to fight obesity. However, the current FDA-approved weight-loss drugs all have significant side effects. Here we show that ribose upregulates gut motility and suppresses mice body weight gain. Ribokinase, which is encoded by Rbks gene, is the first enzyme for ribose metabolism in vivo. Rbks mutation resulted in ribose accumulation in the small intestine, which accelerated gut movement. Ribose oral treatment in wild type mice also enhanced bowel motility and rendered mice resistance to high fat diets. The suppressed weight gain was resulted from enhanced ingested food excretion. In addition, the effective dose of ribose didn't cause any known side effects (i.e. diarrhea and hypoglycemia). Overall, our results show that ribose can regulate gut motility and energy homeostasis in mice, and suggest that administration of ribose and its analogs could regulate gastrointestinal motility, providing a novel therapeutic approach for gastrointestinal dysfunction and weight control. PMID:27194947

  8. Multifunctional fuel additives

    SciTech Connect

    Baillargeon, D.J.; Cardis, A.B.; Heck, D.B.

    1991-03-26

    This paper discusses a composition comprising a major amount of a liquid hydrocarbyl fuel and a minor low-temperature flow properties improving amount of an additive product of the reaction of a suitable diol and product of a benzophenone tetracarboxylic dianhydride and a long-chain hydrocarbyl aminoalcohol.

  9. Biobased lubricant additives

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fully biobased lubricants are those formulated using all biobased ingredients, i.e. biobased base oils and biobased additives. Such formulations provide the maximum environmental, safety, and economic benefits expected from a biobased product. Currently, there are a number of biobased base oils that...

  10. Optimizing weight gain in pregnancy to prevent obesity in women and children.

    PubMed

    Herring, S J; Rose, M Z; Skouteris, H; Oken, E

    2012-03-01

    Pregnancy is now considered to be an important risk factor for new or persistent obesity among women during the childbearing years. High gestational weight gain is the strongest predictor of maternal overweight or obesity following pregnancy. A growing body of evidence also suggests that both high and low gestational weight gains are independently associated with an increased risk of childhood obesity, suggesting that influences occurring very early in life are contributing to obesity onset. In response to these data, the US Institute of Medicine (IOM) revised gestational weight gain guidelines in 2009 for the first time in nearly two decades. However, less than one third of pregnant women achieve guideline-recommended gains, with the majority gaining above IOM recommended levels. To date, interventions to optimize pregnancy weight gains have had mixed success. In this paper, we summarize the evidence from human and animal studies linking over-nutrition and under-nutrition in pregnancy to maternal and child obesity. In addition, we discuss published trials and ongoing interventions to achieve appropriate gestational weight gain as a strategy for obesity prevention in women and their children.

  11. An assessment of wheat breeding gains in hot environments

    NASA Astrophysics Data System (ADS)

    Gourdji, S. M.; Mathews, K.; Reynolds, M.; Crossa, J.; Lobell, D. B.

    2012-12-01

    Wheat, a critical crop for ensuring global food security, has the lowest optimum temperatures among the major cereals, and is already grown in many heat stress areas, thereby increasing risks to production from a warming climate. Historical spring wheat trial data from the International Maize and Wheat Improvement Center (CIMMYT) was used to investigate the relationship between environmental conditions and yield in major wheat-growing areas, assess the response to future warming, and identify different rates of genetic gains due to variety improvement across environments and breeding nurseries. Results were compared for two nurseries: 1) the Elite Spring Wheat Yield Trial (ESWYT), which aims to improve yield potential under optimal environmental conditions, and 2) the Semi-Arid Wheat Yield Trial (SAWYT), where improvements are targeted in semi-arid, rainfed environments, frequently subject to heat and water stress. Yields from 25 years of trial data were paired with reconstructed daily weather data in an empirical model with environmental variables averaged by growth stage. Temperature, radiation, day length and interaction terms between temperature and vapor pressure deficit (VPD) were all determined to be significant terms in the model. Results show a detrimental response to warming across all temperatures in the grain-filling, or final growth stage, particularly under low VPD/ humid conditions. A negative response to warming was also observed in the reproductive stage after ~14C, although high VPD conferred no additional benefit, perhaps due to a higher sensitivity and/or exposure to water stress during this period. A projected 2C season average warming was seen to have differential effects between ESWYT and SAWYT, with SAWYT germplasm less sensitive to warming up until ~21C, but an equally negative response to further warming for both nurseries. The regions where wheat is already grown under hot, and sometimes humid, conditions, particularly in south and south

  12. Plasticity in the adult oculomotor system: offline consolidation phase gains in saccade sequence learning.

    PubMed

    Meital, Noya; Korinth, Sebastian Peter; Karni, Avi

    2013-08-28

    When do adults gain in learning an oculomotor sequence? Here we show that oculomotor training can result not only in performance gains within the training session, but also induce robust offline gains in both speed and accuracy. Participants were trained and tested over two consecutive days to perform a sequence of successive saccades. Saccades were directed to four target letters, presented simultaneously at fixed positions. A two alternative-forced choice question, after each trial, ensured that all targets were perceived. Eye tracking measures were tested at the beginning and end of the training session as well as at 24 h post-training. Practice resulted in within-session gains in accuracy and a reduction of target fixation duration (although total trial duration remained unchanged). In addition, the total average path length traveled by the eye increased, reflecting a decrease in undershoot saccades. At 24 h post-training, however, additional gains were expressed in both speed and accuracy of performance; the total trial duration as well as the fixation-position-offsets and the number of corrective saccades decreased. The expression of delayed gains indicates offline skill consolidation processes in the eye-movement control system. Our results show that the optimization of some aspect, specifically saccade speed parameters, of oculomotor sequence performance evolves mainly offline, during the post-training consolidation phase, a pattern suggestive of learning in an expert system. PMID:23867864

  13. Focusing on Short-Term Achievement Gains Fails to Produce Long-Term Gains

    ERIC Educational Resources Information Center

    Grissmer, David W.; Ober, David R.; Beekman, John A.

    2014-01-01

    The short-term emphasis engendered by No Child Left Behind (NCLB) has focused research predominantly on unraveling the complexities and uncertainties in assessing short-term results, rather than developing methods and assessing results over the longer term. In this paper we focus on estimating long-term gains and address questions important to…

  14. Measurement of population inversions and gain in carbon fiber plasmas

    SciTech Connect

    Milchberg, H.; Skinner, C.H.; Suckewer, S.; Voorhees, D.

    1985-10-01

    A CO/sub 2/ laser (approx.0.5 kJ energy, 70 nsec pulse width) was focussed onto the end of an axially oriented, thick (35 to 350 ..mu..) carbon fiber with or without a magnetic field present along the laser-fiber axis. We present evidence for axial-to-transverse enhancement of the CVI 182A (n = 3 ..-->.. 2) transition, which is correlated with the appearance of a population inversion between levels n = 3 and 2. For the B = 0 kG, zero field case, the maximum gain-length product of kl approx. =3 (k approx. =6 cm/sup -1/) was measured for a carbon fiber coated with a thin layer of aluminum (for additional radiation cooling). The results are interpreted in terms of fast recombination due mostly to thermal conduction from the plasma to the cold fiber core.

  15. Steering, splitting, and cloning of an optical beam in a coherently driven Raman gain system

    NASA Astrophysics Data System (ADS)

    Verma, Onkar N.; Dey, Tarak N.

    2015-01-01

    We propose an all-optical antiwaveguide mechanism for steering, splitting, and cloning of an optical beam without diffraction. We use a spatially inhomogeneous pump beam to create an antiwaveguide structure in a Doppler broadened N -type four-level Raman gain medium for a copropagating weak probe beam. We show that a transverse modulated index of refraction and gain due to the spatially dependent pump beam hold the keys to steering, splitting, and cloning of an optical beam. We have also shown that an additional control field permits the propagation of an optical beam through an otherwise gain medium without diffraction and instability. We further discuss how finesse of the cloned images can be increased by changing the detuning of the control field. We arrive at similar results by using homogeneously broadened gain media at higher density.

  16. Heat gain from thermal radiation through protective clothing with different insulation, reflectivity and vapour permeability.

    PubMed

    Bröde, Peter; Kuklane, Kalev; Candas, Victor; Den Hartog, Emiel A; Griefahn, Barbara; Holmér, Ingvar; Meinander, Harriet; Nocker, Wolfgang; Richards, Mark; Havenith, George

    2010-01-01

    The heat transferred through protective clothing under long wave radiation compared to a reference condition without radiant stress was determined in thermal manikin experiments. The influence of clothing insulation and reflectivity, and the interaction with wind and wet underclothing were considered. Garments with different outer materials and colours and additionally an aluminised reflective suit were combined with different number and types of dry and pre-wetted underwear layers. Under radiant stress, whole body heat loss decreased, i.e., heat gain occurred compared to the reference. This heat gain increased with radiation intensity, and decreased with air velocity and clothing insulation. Except for the reflective outer layer that showed only minimal heat gain over the whole range of radiation intensities, the influence of the outer garments' material and colour was small with dry clothing. Wetting the underclothing for simulating sweat accumulation, however, caused differing effects with higher heat gain in less permeable garments.

  17. Approximate reversibility in the context of entropy gain, information gain, and complete positivity

    NASA Astrophysics Data System (ADS)

    Buscemi, Francesco; Das, Siddhartha; Wilde, Mark M.

    2016-06-01

    There are several inequalities in physics which limit how well we can process physical systems to achieve some intended goal, including the second law of thermodynamics, entropy bounds in quantum information theory, and the uncertainty principle of quantum mechanics. Recent results provide physically meaningful enhancements of these limiting statements, determining how well one can attempt to reverse an irreversible process. In this paper, we apply and extend these results to give strong enhancements to several entropy inequalities, having to do with entropy gain, information gain, entropic disturbance, and complete positivity of open quantum systems dynamics. Our first result is a remainder term for the entropy gain of a quantum channel. This result implies that a small increase in entropy under the action of a subunital channel is a witness to the fact that the channel's adjoint can be used as a recovery map to undo the action of the original channel. We apply this result to pure-loss, quantum-limited amplifier, and phase-insensitive quantum Gaussian channels, showing how a quantum-limited amplifier can serve as a recovery from a pure-loss channel and vice versa. Our second result regards the information gain of a quantum measurement, both without and with quantum side information. We find here that a small information gain implies that it is possible to undo the action of the original measurement if it is efficient. The result also has operational ramifications for the information-theoretic tasks known as measurement compression without and with quantum side information. Our third result shows that the loss of Holevo information caused by the action of a noisy channel on an input ensemble of quantum states is small if and only if the noise can be approximately corrected on average. We finally establish that the reduced dynamics of a system-environment interaction are approximately completely positive and trace preserving if and only if the data processing

  18. Vinyl capped addition polyimides

    NASA Technical Reports Server (NTRS)

    Vannucci, Raymond D. (Inventor); Malarik, Diane C. (Inventor); Delvigs, Peter (Inventor)

    1991-01-01

    Polyimide resins (PMR) are generally useful where high strength and temperature capabilities are required (at temperatures up to about 700 F). Polyimide resins are particularly useful in applications such as jet engine compressor components, for example, blades, vanes, air seals, air splitters, and engine casing parts. Aromatic vinyl capped addition polyimides are obtained by reacting a diamine, an ester of tetracarboxylic acid, and an aromatic vinyl compound. Low void materials with improved oxidative stability when exposed to 700 F air may be fabricated as fiber reinforced high molecular weight capped polyimide composites. The aromatic vinyl capped polyimides are provided with a more aromatic nature and are more thermally stable than highly aliphatic, norbornenyl-type end-capped polyimides employed in PMR resins. The substitution of aromatic vinyl end-caps for norbornenyl end-caps in addition polyimides results in polymers with improved oxidative stability.

  19. Tackifier for addition polyimides

    NASA Technical Reports Server (NTRS)

    Butler, J. M.; St.clair, T. L.

    1980-01-01

    A modification to the addition polyimide, LaRC-160, was prepared to improve tack and drape and increase prepeg out-time. The essentially solventless, high viscosity laminating resin is synthesized from low cost liquid monomers. The modified version takes advantage of a reactive, liquid plasticizer which is used in place of solvent and helps solve a major problem of maintaining good prepeg tack and drape, or the ability of the prepeg to adhere to adjacent plies and conform to a desired shape during the lay up process. This alternate solventless approach allows both longer life of the polymer prepeg and the processing of low void laminates. This approach appears to be applicable to all addition polyimide systems.

  20. Electrophilic addition of astatine

    SciTech Connect

    Norseev, Yu.V.; Vasaros, L.; Nhan, D.D.; Huan, N.K.

    1988-03-01

    It has been shown for the first time that astatine is capable of undergoing addition reactions to unsaturated hydrocarbons. A new compound of astatine, viz., ethylene astatohydrin, has been obtained, and its retention numbers of squalane, Apiezon, and tricresyl phosphate have been found. The influence of various factors on the formation of ethylene astatohydrin has been studied. It has been concluded on the basis of the results obtained that the univalent cations of astatine in an acidic medium is protonated hypoastatous acid.

  1. Functional Generalized Additive Models.

    PubMed

    McLean, Mathew W; Hooker, Giles; Staicu, Ana-Maria; Scheipl, Fabian; Ruppert, David

    2014-01-01

    We introduce the functional generalized additive model (FGAM), a novel regression model for association studies between a scalar response and a functional predictor. We model the link-transformed mean response as the integral with respect to t of F{X(t), t} where F(·,·) is an unknown regression function and X(t) is a functional covariate. Rather than having an additive model in a finite number of principal components as in Müller and Yao (2008), our model incorporates the functional predictor directly and thus our model can be viewed as the natural functional extension of generalized additive models. We estimate F(·,·) using tensor-product B-splines with roughness penalties. A pointwise quantile transformation of the functional predictor is also considered to ensure each tensor-product B-spline has observed data on its support. The methods are evaluated using simulated data and their predictive performance is compared with other competing scalar-on-function regression alternatives. We illustrate the usefulness of our approach through an application to brain tractography, where X(t) is a signal from diffusion tensor imaging at position, t, along a tract in the brain. In one example, the response is disease-status (case or control) and in a second example, it is the score on a cognitive test. R code for performing the simulations and fitting the FGAM can be found in supplemental materials available online.

  2. Progress toward high-gain laser fusion

    SciTech Connect

    Storm, E.

    1988-09-28

    A 1985-1986 Review of the US inertial confinement fusion program by the National Academy of Sciences concluded that five more years might be required to obtain enough data to determine the future course of the program. Since then, data from the Nova laser and from the Halite/Centurion program have resolved most of the outstanding problems identified by the NAS review. In particular, we now believe that we can produce a sufficiently uniform target; that we can keep the energy content in hot electrons and high-energy photons low enough (/approximately/1--10% of drive energy, depending on target design) and achieve enough pulse-shaping accuracy (/approximately/10%, with a dynamic range of 100:1) to keep the fuel on a near-Fermi-degenerate adiabat; that we can produce an /approximately/100-Mbar pressure pulse of sufficient uniformity (/approximately/1%), and can we control hydrodynamic instabilities so that the mix of the pusher into the hot spot is low enough to permit marginal ignition. These results are sufficiently encouraging that the US Department of Energy is planning to complete a 10-MJ laboratory microfusion facility to demonstrate high-gain ICF in the laboratory within a decade. 22 refs., 1 fig.

  3. Proprioceptive feedback determines visuomotor gain in Drosophila

    PubMed Central

    Bartussek, Jan; Lehmann, Fritz-Olaf

    2016-01-01

    Multisensory integration is a prerequisite for effective locomotor control in most animals. Especially, the impressive aerial performance of insects relies on rapid and precise integration of multiple sensory modalities that provide feedback on different time scales. In flies, continuous visual signalling from the compound eyes is fused with phasic proprioceptive feedback to ensure precise neural activation of wing steering muscles (WSM) within narrow temporal phase bands of the stroke cycle. This phase-locked activation relies on mechanoreceptors distributed over wings and gyroscopic halteres. Here we investigate visual steering performance of tethered flying fruit flies with reduced haltere and wing feedback signalling. Using a flight simulator, we evaluated visual object fixation behaviour, optomotor altitude control and saccadic escape reflexes. The behavioural assays show an antagonistic effect of wing and haltere signalling on visuomotor gain during flight. Compared with controls, suppression of haltere feedback attenuates while suppression of wing feedback enhances the animal’s wing steering range. Our results suggest that the generation of motor commands owing to visual perception is dynamically controlled by proprioception. We outline a potential physiological mechanism based on the biomechanical properties of WSM and sensory integration processes at the level of motoneurons. Collectively, the findings contribute to our general understanding how moving animals integrate sensory information with dynamically changing temporal structure. PMID:26909184

  4. Recent results of the GAINS test flight

    NASA Astrophysics Data System (ADS)

    Girz, C.

    A demonstration flight of the Global Atmosphere-ocean IN-situ System (GAINS) Prototype III balloon is scheduled to occur in early summer 2002. The 18-m diameter PIII superpressure balloon, built by GSSL, Inc., will float a 135-kg payload at 16 km. Performance of the SpectraTM envelope will be assessed over two day-night cycles. The payload consists of line-of-sight communications for transmitting GPS position, and monitored parameters on balloon and payload state and the internal and external thermal environments. Primary termination is by radio command with several independent backup termination systems. Safe operation of the balloon is ensured by an onboard transponder that keeps the balloon under active air traffic control. The balloon is tracked by an aircraft that will record communications from the balloon and instigate termination of the flight. Mobile ground stations positioned at the launch and recovery locations will also be capable of recording and terminating the flight. A suite of trajectory forecast tools has been developed based on radiosondes and winds from numerical weather models. A GPS surface reflection experiment for determining ocean surface winds will be tested on this platform. Physical and electronic integration of the radio and mechanical systems was completed over the last two years. Data and videos from the June flight will be presented.

  5. Medical Gains of Chondroitin Sulfate Upon Fucosylation.

    PubMed

    Pomin, Vitor H

    2015-01-01

    Chondroitin sulfate (CS) is a glycosaminoglycan (GAG) composed of alternating N-acetyl galactosamine and glucuronic acid units within disaccharide building blocks. CS is a key functional component in proteoglycans of cartilaginous tissues. Owing to its numerous biological roles, CS is widely explored in the pharmaceutical market as nutraceutical ingredient commonly utilized against arthritis, osteoarthrosis, and sometimes osteoporosis. Tissues like shark cartilage and bovine trachea are common sources of CS. Nonetheless, a new CS type has been introduced and investigated in the last few decades in what regards its medical potentials. It is named fucosylated chondroitin sulfate (FucCS). This less common CS type is isolated exclusively from the body wall of sea cucumbers. The presence of fucosyl branching units in the holothurian FucCS gives to this unique GAG, therapeutic properties in various pathophysiological systems which are inexistent in the common CS explored in the market. Examples of these systems are coagulation, thrombosis, hemodialysis, atherosclerosis, cellular growth, angiogenesis, fibrosis, tumor growth, inflammation, viral and protozoan infections, hyperglycemia, diabetes-related pathological events and tissue damage. This report aims at describing the medical benefits gained upon fucosylation of CS. Clinical prospects of these medical benefits are also discussed herein.

  6. GD SDR Automatic Gain Control Characterization Testing

    NASA Technical Reports Server (NTRS)

    Nappier, Jennifer M.; Briones, Janette C.

    2013-01-01

    The General Dynamics (GD) S-Band software defined radio (SDR) in the Space Communications and Navigation (SCAN) Testbed on the International Space Station (ISS) will provide experimenters an opportunity to develop and demonstrate experimental waveforms in space. The GD SDR platform and initial waveform were characterized on the ground before launch and the data will be compared to the data that will be collected during on-orbit operations. A desired function of the SDR is to estimate the received signal to noise ratio (SNR), which would enable experimenters to better determine on-orbit link conditions. The GD SDR does not have an SNR estimator, but it does have an analog and a digital automatic gain control (AGC). The AGCs can be used to estimate the SDR input power which can be converted into a SNR. Tests were conducted to characterize the AGC response to changes in SDR input power and temperature. This purpose of this paper is to describe the tests that were conducted, discuss the results showi ng how the AGCs relate to the SDR input power, and provide recommendations for AGC testing and characterization.

  7. GD SDR Automatic Gain Control Characterization Testing

    NASA Technical Reports Server (NTRS)

    Nappier, Jennifer M.; Briones, Janette C.

    2013-01-01

    The General Dynamics (GD) S-Band software defined radio (SDR) in the Space Communications and Navigation (SCAN) Testbed on the International Space Station (ISS) will provide experimenters an opportunity to develop and demonstrate experimental waveforms in space. The GD SDR platform and initial waveform were characterized on the ground before launch and the data will be compared to the data that will be collected during on-orbit operations. A desired function of the SDR is to estimate the received signal to noise ratio (SNR), which would enable experimenters to better determine on-orbit link conditions. The GD SDR does not have an SNR estimator, but it does have an analog and a digital automatic gain control (AGC). The AGCs can be used to estimate the SDR input power which can be converted into a SNR. Tests were conducted to characterize the AGC response to changes in SDR input power and temperature. This purpose of this paper is to describe the tests that were conducted, discuss the results showing how the AGCs relate to the SDR input power, and provide recommendations for AGC testing and characterization.

  8. Medical Gains of Chondroitin Sulfate Upon Fucosylation.

    PubMed

    Pomin, Vitor H

    2015-01-01

    Chondroitin sulfate (CS) is a glycosaminoglycan (GAG) composed of alternating N-acetyl galactosamine and glucuronic acid units within disaccharide building blocks. CS is a key functional component in proteoglycans of cartilaginous tissues. Owing to its numerous biological roles, CS is widely explored in the pharmaceutical market as nutraceutical ingredient commonly utilized against arthritis, osteoarthrosis, and sometimes osteoporosis. Tissues like shark cartilage and bovine trachea are common sources of CS. Nonetheless, a new CS type has been introduced and investigated in the last few decades in what regards its medical potentials. It is named fucosylated chondroitin sulfate (FucCS). This less common CS type is isolated exclusively from the body wall of sea cucumbers. The presence of fucosyl branching units in the holothurian FucCS gives to this unique GAG, therapeutic properties in various pathophysiological systems which are inexistent in the common CS explored in the market. Examples of these systems are coagulation, thrombosis, hemodialysis, atherosclerosis, cellular growth, angiogenesis, fibrosis, tumor growth, inflammation, viral and protozoan infections, hyperglycemia, diabetes-related pathological events and tissue damage. This report aims at describing the medical benefits gained upon fucosylation of CS. Clinical prospects of these medical benefits are also discussed herein. PMID:26560742

  9. Among farm variation in heifer BW gains.

    PubMed

    Bond, G B; von Keyserlingk, M A G; Chapinal, N; Pajor, E A; Weary, D M

    2015-11-01

    BW of replacement heifers is rarely measured on commercial farms, making it difficult to evaluate the success of management practices related to calf growth. Our aims were to describe variability among commercial farms in Holstein heifer BW, determine how BW differences varied with management and propose a method of estimating calf growth based upon single measurement. Heart girth circumference was used to estimate BW of 576 heifers 48 to 70 weeks of age on 33 different farms (on average 11 ± 6 heifers/farm) in British Columbia, Canada. Regression analysis showed a linear relationship of BW with age (BW (kg)=116+5 × age (weeks)). Residuals from this regression were averaged across heifers within each farm to identify farms where heifers were heavier or lighter than would be predicted on the basis of their age; farm average residuals ranged from -54 to 72 kg. Farms with heifers showing the highest residual BW also had the highest rates of gain for pre-weaned calves. These results indicate that farms able to rear faster growing calves before weaning were also rearing faster growing heifers at breeding, and suggest that management of milk-fed calves is a particularly important component of replacement heifer management. PMID:26477529

  10. 34 CFR 462.43 - How is educational gain measured?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 34 Education 3 2011-07-01 2011-07-01 false How is educational gain measured? 462.43 Section 462.43... Educational Gain? § 462.43 How is educational gain measured? (a)(1) Educational gain is measured by comparing... reading score on the pre-test with the reading score on the post-test. (2) A student is considered to...

  11. Assessment of learning gains in a flipped biochemistry classroom.

    PubMed

    Ojennus, Deanna Dahlke

    2016-01-01

    The flipped classroom has become an increasingly popular pedagogical approach to teaching and learning. In this study, learning gains were assessed in a flipped biochemistry course and compared to gains in a traditional lecture. Although measured learning gains were not significantly different between the two courses, student perception of learning gains did differ and indicates a higher level of satisfaction with the flipped lecture format.

  12. 24 CFR 3280.506 - Heat loss/heat gain.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 24 Housing and Urban Development 5 2014-04-01 2014-04-01 false Heat loss/heat gain. 3280.506... URBAN DEVELOPMENT MANUFACTURED HOME CONSTRUCTION AND SAFETY STANDARDS Thermal Protection § 3280.506 Heat loss/heat gain. The manufactured home heat loss/heat gain shall be determined by methods outlined...

  13. 24 CFR 3280.506 - Heat loss/heat gain.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 24 Housing and Urban Development 5 2012-04-01 2012-04-01 false Heat loss/heat gain. 3280.506... URBAN DEVELOPMENT MANUFACTURED HOME CONSTRUCTION AND SAFETY STANDARDS Thermal Protection § 3280.506 Heat loss/heat gain. The manufactured home heat loss/heat gain shall be determined by methods outlined...

  14. 24 CFR 3280.506 - Heat loss/heat gain.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 24 Housing and Urban Development 5 2013-04-01 2013-04-01 false Heat loss/heat gain. 3280.506... URBAN DEVELOPMENT MANUFACTURED HOME CONSTRUCTION AND SAFETY STANDARDS Thermal Protection § 3280.506 Heat loss/heat gain. The manufactured home heat loss/heat gain shall be determined by methods outlined...

  15. 20 CFR 416.910 - Meaning of substantial gainful activity.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 20 Employees' Benefits 2 2011-04-01 2011-04-01 false Meaning of substantial gainful activity. 416....910 Meaning of substantial gainful activity. Substantial gainful activity means work that— (a) Involves doing significant and productive physical or mental duties; and (b) Is done (or intended) for...

  16. 20 CFR 220.141 - Substantial gainful activity, defined.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...) Substantial work activity. Substantial work activity is work activity that involves doing significant physical... 20 Employees' Benefits 1 2011-04-01 2011-04-01 false Substantial gainful activity, defined. 220... RETIREMENT ACT DETERMINING DISABILITY Substantial Gainful Activity § 220.141 Substantial gainful...

  17. Assessment of Learning Gains in a Flipped Biochemistry Classroom

    ERIC Educational Resources Information Center

    Ojennus, Deanna Dahlke

    2016-01-01

    The flipped classroom has become an increasingly popular pedagogical approach to teaching and learning. In this study, learning gains were assessed in a flipped biochemistry course and compared to gains in a traditional lecture. Although measured learning gains were not significantly different between the two courses, student perception of…

  18. 20 CFR 220.141 - Substantial gainful activity, defined.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...) Substantial work activity. Substantial work activity is work activity that involves doing significant physical... 20 Employees' Benefits 1 2010-04-01 2010-04-01 false Substantial gainful activity, defined. 220... RETIREMENT ACT DETERMINING DISABILITY Substantial Gainful Activity § 220.141 Substantial gainful...

  19. 20 CFR 416.910 - Meaning of substantial gainful activity.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false Meaning of substantial gainful activity. 416....910 Meaning of substantial gainful activity. Substantial gainful activity means work that— (a) Involves doing significant and productive physical or mental duties; and (b) Is done (or intended) for...

  20. Absolute gain measurement of microstrip antennas under mismatched conditions

    NASA Technical Reports Server (NTRS)

    Lee, R. Q.; Baddour, M. F.

    1988-01-01

    The gain of a single microstrip patch and a two-layer parasitic array is measured using the image method under mismatched conditions. This method produces accurate results, even in the case of low-gain microstrip antennas. The advantages of this method over the gain comparison technique are discussed.

  1. Problems with IQ Gains: The Huge Vocabulary Gap

    ERIC Educational Resources Information Center

    Flynn, James R.

    2010-01-01

    Despite Kaufman, Raven's Progressive Matrices and the Wechsler subtest Similarities are tests whose gains call for special explanation. The spread of "scientific spectacles" is the key, but its explanatory potential has been exhausted. Three trends force us to look elsewhere: (a) gains on Wechsler subtests such as Picture Arrangement, (b) gains in…

  2. 26 CFR 1.1247-3 - Treatment of capital gains.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 11 2010-04-01 2010-04-01 true Treatment of capital gains. 1.1247-3 Section 1... (CONTINUED) INCOME TAXES Special Rules for Determining Capital Gains and Losses § 1.1247-3 Treatment of capital gains. (a) Treatment by the company—(1) In general. If an election to distribute income...

  3. Collective Bargaining and Multiple Control Gains in Education.

    ERIC Educational Resources Information Center

    Crisci, Pat E.; Giancola, Joseph M.

    1986-01-01

    Outlines a study of the use of "control gains" in collective bargaining contracts of teacher unions in Ohio. Control gains are contract items that give unions control over some aspect of the work environment in lieu of financial gains. They can be offered in contract negotiations when school boards have limited funds. (MD)

  4. 26 CFR 1.1247-3 - Treatment of capital gains.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 26 Internal Revenue 11 2013-04-01 2013-04-01 false Treatment of capital gains. 1.1247-3 Section 1... Treatment of capital gains. (a) Treatment by the company—(1) In general. If an election to distribute income... made. (b) Treatment of capital gains by qualified shareholder—(1) Definition of qualified...

  5. 26 CFR 1.1247-3 - Treatment of capital gains.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 26 Internal Revenue 11 2012-04-01 2012-04-01 false Treatment of capital gains. 1.1247-3 Section 1... Treatment of capital gains. (a) Treatment by the company—(1) In general. If an election to distribute income... made. (b) Treatment of capital gains by qualified shareholder—(1) Definition of qualified...

  6. Intracavity gain shaping in millijoule-level, high gain Ho:YLF regenerative amplifiers.

    PubMed

    Murari, Krishna; Cankaya, Huseyin; Kroetz, Peter; Cirmi, Giovanni; Li, Peng; Ruehl, Axel; Hartl, Ingmar; Kärtner, Franz X

    2016-03-15

    We demonstrate intracavity gain shaping inside a 2 μm Ho:YLF regenerative amplifier with a spectral bandwidth of 2.9 nm broadened to 5.4 nm, corresponding to Fourier-limited pulses of 1 ps duration. The intracavity gain shaping is achieved by using a simple etalon, which acts as a frequency-selective filter. The output of the regenerative amplifier is amplified by a single-pass amplifier, and we achieve total energy of 2.2 mJ and pulse duration of 2.4 ps at 1 kHz with pulse fluctuations <1%. The amplifier chain is seeded by a home-built mode-locked holmium-doped fiber oscillator. PMID:26977647

  7. Muscle mass gain after resistance training is inversely correlated with trunk adiposity gain in postmenopausal women.

    PubMed

    Orsatti, Fábio L; Nahas, Eliana A P; Orsatti, Cláudio L; de Oliveira, Erick P; Nahas-Neto, Jorge; da Mota, Gustavo R; Burini, Roberto C

    2012-08-01

    The aim of this study was to evaluate alterations in trunk adiposity (TA) over 9 months of resistance training (RT) and associate these changes with the hypertrophy of muscle mass (MM) in postmenopausal women (PW). The investigation used a sample that consisted of 22 PW (44-69 years old). The group was subjected to RT (60-80% of 1 repetition maximum) for the total body 3 d · wk(-1). Body composition (dual-energy x-ray absorptiometry) and plasma levels of insulin-like growth factor-1 (IGF-1), follicle-stimulating hormone, E2 (Immulite system), and interleukin-6 (IL-6; enzyme-linked immunosorbent assay) were assessed at the beginning and end of the experiment. After RT, only women who acquired up to 5% TA gained MM, whereas women who acquired >5% TA exhibited increased IL-6 and no MM gain (p < 0.05). The ΔMM was negatively associated with time of menopause (r = -0.45, p < 0.05) and positively associated with baseline IGF-1 (r = 0.47, p < 0.05). Only ΔLE (leg extension) was negatively associated with baseline IL-6 (p < 0.05). Trunk adiposity growth (ΔTF, kilograms) was positively correlated with changes in IL-6 (r = 0.68, p < 0.05). The MM gain was negatively correlated with ΔTF (r = -0.63, p < 0.05) and changes in IL-6 (r = -0.73, p < 0.05). After adjusting all of the confounding variables, only baseline IGF-1 (positively) and changes in IL-6 (negatively) influenced MM, and only the increase in TA influenced IL-6. Our study suggests that increased levels of TA during RT increase IL-6 concentrations, which is a significant negative predictor of MM gain in PW.

  8. Are videogame training gains specific or general?

    PubMed

    Oei, Adam C; Patterson, Michael D

    2014-01-01

    Many recent studies using healthy adults document enhancements in perception and cognition from playing commercial action videogames (AVGs). Playing action games (e.g., Call of Duty, Medal of Honor) is associated with improved bottom-up lower-level information processing skills like visual-perceptual and attentional processes. One proposal states a general improvement in the ability to interpret and gather statistical information to predict future actions which then leads to better performance across different perceptual/attentional tasks. Another proposal claims all the tasks are separately trained in the AVGs because the AVGs and laboratory tasks contain similar demands. We review studies of action and non-AVGs to show support for the latter proposal. To explain transfer in AVGs, we argue that the perceptual and attention tasks share common demands with the trained videogames (e.g., multiple object tracking (MOT), rapid attentional switches, and peripheral vision). In non-AVGs, several studies also demonstrate specific, limited transfer. One instance of specific transfer is the specific enhancement to mental rotation after training in games with a spatial emphasis (e.g., Tetris). In contrast, the evidence for transfer is equivocal where the game and task do not share common demands (e.g., executive functioning). Thus, the "common demands" hypothesis of transfer not only characterizes transfer effects in AVGs, but also non-action games. Furthermore, such a theory provides specific predictions, which can help in the selection of games to train human cognition as well as in the design of videogames purposed for human cognitive and perceptual enhancement. Finally this hypothesis is consistent with the cognitive training literature where most post-training gains are for tasks similar to the training rather than general, non-specific improvements.

  9. Are videogame training gains specific or general?

    PubMed

    Oei, Adam C; Patterson, Michael D

    2014-01-01

    Many recent studies using healthy adults document enhancements in perception and cognition from playing commercial action videogames (AVGs). Playing action games (e.g., Call of Duty, Medal of Honor) is associated with improved bottom-up lower-level information processing skills like visual-perceptual and attentional processes. One proposal states a general improvement in the ability to interpret and gather statistical information to predict future actions which then leads to better performance across different perceptual/attentional tasks. Another proposal claims all the tasks are separately trained in the AVGs because the AVGs and laboratory tasks contain similar demands. We review studies of action and non-AVGs to show support for the latter proposal. To explain transfer in AVGs, we argue that the perceptual and attention tasks share common demands with the trained videogames (e.g., multiple object tracking (MOT), rapid attentional switches, and peripheral vision). In non-AVGs, several studies also demonstrate specific, limited transfer. One instance of specific transfer is the specific enhancement to mental rotation after training in games with a spatial emphasis (e.g., Tetris). In contrast, the evidence for transfer is equivocal where the game and task do not share common demands (e.g., executive functioning). Thus, the "common demands" hypothesis of transfer not only characterizes transfer effects in AVGs, but also non-action games. Furthermore, such a theory provides specific predictions, which can help in the selection of games to train human cognition as well as in the design of videogames purposed for human cognitive and perceptual enhancement. Finally this hypothesis is consistent with the cognitive training literature where most post-training gains are for tasks similar to the training rather than general, non-specific improvements. PMID:24782722

  10. Fundamental limitations to gain enhancement in periodic media and waveguides.

    PubMed

    Grgić, Jure; Ott, Johan Raunkjær; Wang, Fengwen; Sigmund, Ole; Jauho, Antti-Pekka; Mørk, Jesper; Mortensen, N Asger

    2012-05-01

    A common strategy to compensate for losses in optical nanostructures is to add gain material in the system. By exploiting slow-light effects it is expected that the gain may be enhanced beyond its bulk value. Here we show that this route cannot be followed uncritically: inclusion of gain inevitably modifies the underlying dispersion law, and thereby may degrade the slow-light properties underlying the device operation and the anticipated gain enhancement itself. This degradation is generic; we demonstrate it for three different systems of current interest (coupled-resonator optical waveguides, Bragg stacks, and photonic crystal waveguides). Nevertheless, a small amount of added gain may be beneficial.

  11. Performance Boosting Additive

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Mainstream Engineering Corporation was awarded Phase I and Phase II contracts from Goddard Space Flight Center's Small Business Innovation Research (SBIR) program in early 1990. With support from the SBIR program, Mainstream Engineering Corporation has developed a unique low cost additive, QwikBoost (TM), that increases the performance of air conditioners, heat pumps, refrigerators, and freezers. Because of the energy and environmental benefits of QwikBoost, Mainstream received the Tibbetts Award at a White House Ceremony on October 16, 1997. QwikBoost was introduced at the 1998 International Air Conditioning, Heating, and Refrigeration Exposition. QwikBoost is packaged in a handy 3-ounce can (pressurized with R-134a) and will be available for automotive air conditioning systems in summer 1998.

  12. Sewage sludge additive

    NASA Technical Reports Server (NTRS)

    Kalvinskas, J. J.; Mueller, W. A.; Ingham, J. D. (Inventor)

    1980-01-01

    The additive is for a raw sewage treatment process of the type where settling tanks are used for the purpose of permitting the suspended matter in the raw sewage to be settled as well as to permit adsorption of the dissolved contaminants in the water of the sewage. The sludge, which settles down to the bottom of the settling tank is extracted, pyrolyzed and activated to form activated carbon and ash which is mixed with the sewage prior to its introduction into the settling tank. The sludge does not provide all of the activated carbon and ash required for adequate treatment of the raw sewage. It is necessary to add carbon to the process and instead of expensive commercial carbon, coal is used to provide the carbon supplement.

  13. Perspectives on Additive Manufacturing

    NASA Astrophysics Data System (ADS)

    Bourell, David L.

    2016-07-01

    Additive manufacturing (AM) has skyrocketed in visibility commercially and in the public sector. This article describes the development of this field from early layered manufacturing approaches of photosculpture, topography, and material deposition. Certain precursors to modern AM processes are also briefly described. The growth of the field over the last 30 years is presented. Included is the standard delineation of AM technologies into seven broad categories. The economics of AM part generation is considered, and the impacts of the economics on application sectors are described. On the basis of current trends, the future outlook will include a convergence of AM fabricators, mass-produced AM fabricators, enabling of topology optimization designs, and specialization in the AM legal arena. Long-term developments with huge impact are organ printing and volume-based printing.

  14. Sarks as additional fermions

    NASA Astrophysics Data System (ADS)

    Agrawal, Jyoti; Frampton, Paul H.; Jack Ng, Y.; Nishino, Hitoshi; Yasuda, Osamu

    1991-03-01

    An extension of the standard model is proposed. The gauge group is SU(2) X ⊗ SU(3) C ⊗ SU(2) S ⊗ U(1) Q, where all gauge symmetries are unbroken. The colour and electric charge are combined with SU(2) S which becomes strongly coupled at approximately 500 GeV and binds preons to form fermionic and vector bound states. The usual quarks and leptons are singlets under SU(2) X but additional fermions, called sarks. transform under it and the electroweak group. The present model explains why no more than three light quark-lepton families can exist. Neutral sark baryons, called narks, are candidates for the cosmological dark matter having the characteristics designed for WIMPS. Further phenomenological implications of sarks are analyzed i including electron-positron annihilation. Z 0 decay, flavor-changing neutral currents. baryon-number non-conservation, sarkonium and the neutron electric dipole moment.

  15. MWD gains as formation-evaluation tool

    SciTech Connect

    Rao, M.V.; Fontenot, J.E.

    1988-02-08

    A comparison of measuring while drilling (MWD) and wire line methods as alternatives for formation evaluation is now pertinent. The recent addition of neutron porosity and formation density logs to the MWD logging sutie has significantly advanced it as a tool for quantitative formation evaluation. Though wire line measurements are far from obsolete, their replacement by MWD is becoming more common, particularly in high-angle holes. This is the second article in a series on MWD.

  16. Mechanism of the metallic metamaterials coupled to the gain material.

    PubMed

    Huang, Zhixiang; Droulias, Sotiris; Koschny, Thomas; Soukoulis, Costas M

    2014-11-17

    We present evidence of strong coupling between the gain material and the metallic metamaterials. It is of vital importance to understand the mechanism of the coupling of metamaterials with the gain medium. Using a four-level gain system, the numerical pump-probe experiments are performed in several configurations (split-ring resonators (SRRs), inverse SRRs and fishnets) of metamaterials, demonstrating reduction of the resonator damping in all cases and hence the possibility for loss compensation. We find that the differential transmittance ΔT/T can be negative in different SRR configurations, such as SRRs on the top of the gain substrate, gain in the SRR gap and gain covering the SRR structure, while in the fishnet metamaterial with gain ΔT/T is positive.

  17. Biological determinants of pregnancy weight gain in a Filipino population.

    PubMed

    Siega-Riz, A M; Adair, L S

    1993-03-01

    Patterns of pregnancy weight gain and predictors of first trimester and total weight gain were investigated in a sample of 1367 women from Cebu, Philippines, with pregnancy intervals of < 2 y. The mean total weight gain based on actual measurements of prepregnant weight was 8.4 kg. Controlling for gestational week when weight was measured, multivariate-regression models predicted higher first trimester weight gain with higher parity, lower prepregnant body mass index (BMI), and longer nonpregnant intervals. Higher total weight gain was associated with longer nonpregnant intervals, lower prepregnant BMI, taller maternal stature, and relatively high dietary energy intakes. Lactation into the third trimester of pregnancy and maternal age over 35 y had significant negative effects on total weight gain. Given the importance of maternal weight gain in predicting birth outcome, this study provides information on modifiable risk factors that should be considered when developing maternal-infant health policy and programs.

  18. Cognitive Representations of Future Gains, Maintenance, and Losses in the Second Half of Life

    ERIC Educational Resources Information Center

    Timmer, Erika; Steverink, Nardi; Dittmann-Kohli, Freya

    2002-01-01

    The aim of this study is to explore three different developmental dimensions in an aging population. Based on sentence completion responses, the investigation examines personal anticipations of possible gains, maintenance, and losses. Additionally, the effects of age and other personal and situational factors are examined. The study sample…

  19. Delivering pump light to a laser gain element while maintaining access to the laser beam

    DOEpatents

    Beach, Raymond J.; Honea, Eric C.; Payne, Stephen A.

    2001-01-01

    A lens duct is used for pump delivery and the laser beam is accessed through an additional component called the intermediate beam extractor which can be implemented as part of the gain element, part of the lens duct or a separate component entirely.

  20. Open-Access Colleges Responsible for Greatest Gains in Graduation Rates. Policy Alert

    ERIC Educational Resources Information Center

    Doyle, William R.

    2010-01-01

    The largest gains in graduation rates over the past decade have been accomplished at open-access or nearly open-access colleges and universities. In addition, states could see even bigger increases if they directed their policies and supports toward improving graduation rates at these nonselective institutions. These findings from the author's…

  1. A psychometric assessment of the GAIN individual severity scale (GAIN-GISS) and short screeners (GAIN-SS) among adolescents in outpatient treatment programs.

    PubMed

    Stucky, Brian D; Edelen, Maria Orlando; Ramchand, Rajeev

    2014-02-01

    The global appraisal of individual needs (GAIN)-general individual severity scale (GAIN-GISS), and GAIN-short screener (GAIN-SS) are widely used diagnostic measures of internalizing disorders, externalizing disorders, substance abuse, and criminal and violent behavior. Although prevalent in clinical and research settings, there is only limited psychometric evidence of the dimensional structure of these scales. Our investigation used intake data from 6,909 adolescents presenting to outpatient substance abuse treatment facilities in the United States. Our analytic approach used exploratory and item factor analyses to evaluate the underlying factor structure. Multi- and unidimensional item response theory models were employed to evaluate the utility of the scales at providing precise score estimates at various locations of severity. Most scales were confirmed as unidimensional; scales with evidence of multidimensionality, identified as having a weak general dimension and strong specific dimensions using a bifactor IRT model, include the Crime and Violence Scale and the GAIN-SS.

  2. A Psychometric Assessment of the GAIN General Individual Severity Scale (GAIN-GISS) and Short Screeners (GAIN-SS) Among Adolescents in Outpatient Treatment Programs

    PubMed Central

    Stucky, Brian D.; Edelen, Maria Orlando; Ramchand, Rajeev

    2013-01-01

    The Global Appraisal of Individual Needs (GAIN) - General Individual Severity Scale (GAIN-GISS), and GAIN-Short Screener (GAIN-SS) are widely used diagnostic measures of internalizing disorders, externalizing disorders, substance abuse, and criminal and violent behavior. Though prevalent in clinical and research settings, there is only limited psychometric evidence of the dimensional structure of these scales. Our investigation used intake data from 6,909 adolescents presenting to outpatient substance abuse treatment facilities in the United States. Our analytic approach used exploratory and item factor analyses to evaluate the underlying factor structure. Multi- and unidimensional item response theory models were employed to evaluate the utility of the scales at providing precise score estimates at various locations of severity. Most scales were confirmed as unidimensional; scales with evidence of multidimensionality, identified as having a weak general dimension and strong specific dimensions using a bifactor IRT model, include the Crime Violence Scale and the GAIN-SS. PMID:23994048

  3. Divergence and Convergence of Risky Decision Making Across Prospective Gains and Losses: Preferences and Strategies.

    PubMed

    Kurnianingsih, Yoanna A; Mullette-Gillman, O'Dhaniel A

    2015-01-01

    People choose differently when facing potential gains than when facing potential losses. Clear gross differences in decision making between gains and losses have been empirically demonstrated in numerous studies (e.g., framing effect, risk preference, loss aversion). However, theories maintain that there are strong underlying connections (e.g., reflection effect). We investigated the relationship between gains and losses decision making, examining risk preferences, and choice strategies (the reliance on option information) using a monetary gamble task with interleaved trials. For risk preferences, participants were on average risk averse in the gains domain and risk neutral/seeking in the losses domain. We specifically tested for a theoretically hypothesized correlation between individual risk preferences across the gains and losses domains (the reflection effect), but found no significant relationship in the predicted direction. Interestingly, despite the lack of reflected risk preferences, cross-domain risk preferences were still informative of individual choice behavior. For choice strategies, in both domains participants relied more heavily on the maximizing strategy than the satisficing strategy, with increased reliance on the maximizing strategy in the losses domain. Additionally, while there is no mathematical reliance between the risk preference and strategy metrics, within both domains there were significant relationships between risk preferences and strategies-the more participants relied upon the maximizing strategy the more risk neutral they were (equating value and utility maximization). These results demonstrate the complexity of gains and losses decision making, indicating the apparent contradiction that their underlying cognitive/neural processes are both dissociable and overlapping.

  4. Novel Introner-Like Elements in fungi Are Involved in Parallel Gains of Spliceosomal Introns.

    PubMed

    Collemare, Jérôme; Beenen, Henriek G; Crous, Pedro W; de Wit, Pierre J G M; van der Burgt, Ate

    2015-01-01

    Spliceosomal introns are key components of the eukaryotic gene structure. Although they contributed to the emergence of eukaryotes, their origin remains elusive. In fungi, they might originate from the multiplication of invasive introns named Introner-Like Elements (ILEs). However, so far ILEs have been observed in six fungal species only, including Fulvia fulva and Dothistroma septosporum (Dothideomycetes), arguing against ILE insertion as a general mechanism for intron gain. Here, we identified novel ILEs in eight additional fungal species that are phylogenetically related to F. fulva and D. septosporum using PCR amplification with primers derived from previously identified ILEs. The ILE content appeared unique to each species, suggesting independent multiplication events. Interestingly, we identified four genes each containing two gained ILEs. By analysing intron positions in orthologues of these four genes in Ascomycota, we found that three ILEs had inserted within a 15 bp window that contains regular spliceosomal introns in other fungal species. These three positions are not the result of intron sliding because ILEs are newly gained introns. Furthermore, the alternative hypothesis of an inferred ancestral gain followed by independent losses contradicts the observed degeneration of ILEs. These observations clearly indicate three parallel intron gains in four genes that were randomly identified. Our findings suggest that parallel intron gain is a phenomenon that has been highly underestimated in ILE-containing fungi, and likely in the whole fungal kingdom.

  5. Factors Influencing Student Gains from Undergraduate Research Experiences at a Hispanic-Serving Institution.

    PubMed

    Daniels, Heather; Grineski, Sara E; Collins, Timothy W; Morales, Danielle X; Morera, Osvaldo; Echegoyen, Lourdes

    2016-01-01

    Undergraduate research experiences (UREs) confer many benefits to students, including improved self-confidence, better communication skills, and an increased likelihood of pursuing science careers. Additionally, UREs may be particularly important for racial/ethnic minority students who are underrepresented in the science workforce. We examined factors hypothetically relevant to underrepresented minority student gains from UREs at a Hispanic-serving institution, such as mentoring quality, family income, being Latino/a, and caring for dependents. Data came from a 2013 survey of University of Texas at El Paso students engaged in 10 URE programs (n = 227). Using generalized linear models (GzLMs) and adjusting for known covariates, we found that students who reported receiving higher-quality mentorship, spending more hours caring for dependents, and receiving more programmatic resources experienced significantly greater gains from their URE in all three areas we examined (i.e., thinking and working like a scientist, personal gains, and gains in skills). In two of three areas, duration of the URE was positive and significant. Being Latino/a was positive and significant only in the model predicting personal gains. Across the three models, quality of mentorship was the most important correlate of gains. This suggests that providing training to faculty mentors involved in UREs may improve student outcomes and increase program efficacy.

  6. Rate and gain limitations of MSGCs and MGCs combined with GEM and other preamplification structures

    NASA Astrophysics Data System (ADS)

    Fonte, P.; Peskov, V.; Ramsey, B. D.

    1998-12-01

    We have studied the rate and gain limits of diamond-coated Microstrip Gas Counters (MSGCs) and Micro-Gap Counters (MGCs) when combined with various preamplification structures: Gas Electron Multiplier (GEM), Parallel-Plate Avalanche Chamber (PPAC) or a MICROMEGAS-type structure. Measurements were done both with X-rays and alpha particles with various detector geometries and in different gas mixtures at pressures from 0.05 to 10 atm. The results obtained varied significantly with detector design, gas mixture and pressure, but some general features can be identified. We found that in all cases, bare MSGCs, MGCs, PPACs and MICROMEGAS, the maximum achievable gain drops with rate. The addition of preamplification structures significantly increases the gain of MSGCs and MGCs, but this gain is still rate dependent. There would seem to be a general rate-dependant effect governing the usable gain of all these detectors. We speculate on possible mechanisms for this effect, and identify a safe, spark-free, operation zone for each system (detector + preamplification structure) in the rate-gain coordinate plane.

  7. Factors Influencing Student Gains from Undergraduate Research Experiences at a Hispanic-Serving Institution.

    PubMed

    Daniels, Heather; Grineski, Sara E; Collins, Timothy W; Morales, Danielle X; Morera, Osvaldo; Echegoyen, Lourdes

    2016-01-01

    Undergraduate research experiences (UREs) confer many benefits to students, including improved self-confidence, better communication skills, and an increased likelihood of pursuing science careers. Additionally, UREs may be particularly important for racial/ethnic minority students who are underrepresented in the science workforce. We examined factors hypothetically relevant to underrepresented minority student gains from UREs at a Hispanic-serving institution, such as mentoring quality, family income, being Latino/a, and caring for dependents. Data came from a 2013 survey of University of Texas at El Paso students engaged in 10 URE programs (n = 227). Using generalized linear models (GzLMs) and adjusting for known covariates, we found that students who reported receiving higher-quality mentorship, spending more hours caring for dependents, and receiving more programmatic resources experienced significantly greater gains from their URE in all three areas we examined (i.e., thinking and working like a scientist, personal gains, and gains in skills). In two of three areas, duration of the URE was positive and significant. Being Latino/a was positive and significant only in the model predicting personal gains. Across the three models, quality of mentorship was the most important correlate of gains. This suggests that providing training to faculty mentors involved in UREs may improve student outcomes and increase program efficacy. PMID:27521234

  8. Factors Influencing Student Gains from Undergraduate Research Experiences at a Hispanic-Serving Institution

    PubMed Central

    Daniels, Heather; Grineski, Sara E.; Collins, Timothy W.; Morales, Danielle X.; Morera, Osvaldo; Echegoyen, Lourdes

    2016-01-01

    Undergraduate research experiences (UREs) confer many benefits to students, including improved self-confidence, better communication skills, and an increased likelihood of pursuing science careers. Additionally, UREs may be particularly important for racial/ethnic minority students who are underrepresented in the science workforce. We examined factors hypothetically relevant to underrepresented minority student gains from UREs at a Hispanic-serving institution, such as mentoring quality, family income, being Latino/a, and caring for dependents. Data came from a 2013 survey of University of Texas at El Paso students engaged in 10 URE programs (n = 227). Using generalized linear models (GzLMs) and adjusting for known covariates, we found that students who reported receiving higher-quality mentorship, spending more hours caring for dependents, and receiving more programmatic resources experienced significantly greater gains from their URE in all three areas we examined (i.e., thinking and working like a scientist, personal gains, and gains in skills). In two of three areas, duration of the URE was positive and significant. Being Latino/a was positive and significant only in the model predicting personal gains. Across the three models, quality of mentorship was the most important correlate of gains. This suggests that providing training to faculty mentors involved in UREs may improve student outcomes and increase program efficacy. PMID:27521234

  9. The effect of framing incentives as either losses or gains with contingency management for smoking cessation.

    PubMed

    Romanowich, Paul; Lamb, R J

    2013-04-01

    Cumulative prospect theory predicts that losses motivate behavior more than equal gains. Contingency management procedures effectively reduce drug use by placing incentives in direct competition with the drug taking behavior. Therefore, framing incentives as losses, rather than gains should decrease drug use to a greater extent, given equivalent incentives. We examined whether contingent vouchers described as either losses or gains differentially affected smoking abstinence rates. Over 5 consecutive days, participants could either gain $75 per day for verified abstinence or lose $75 per day (initial endowment=$375) for continuing to smoke. As a result, loss-framed participants were more likely to achieve at least one day of abstinence. There was a trend towards loss-framed participants reducing the amount smoked more than gain-framed participants. However, participants in the gain-framed group were more likely to maintain abstinence, once initiated. The results partially support cumulative prospect theory and suggest additional ways to initiate behavior change using incentives, outside of using larger magnitude incentives in contingency management procedures. PMID:23403276

  10. Rate and Gain Limitations of MSGC's and MGC's Combined with GEM and other Preamplification Structures

    NASA Technical Reports Server (NTRS)

    Fonte, P.; Peskov, V.; Ramsey, B. D.

    1998-01-01

    We have studied the rate and gain limits of diamond-coated Microstrip Gas Counters (MSGC's) and Micro-Gap Counters (MGC's) when combined with various preamplification structures: Gas Electron Multiplier (GEM), Parallel-Plate Avalanche Chamber (PPAC) or a MICROMEGAS-type structure. Measurements were done both with X rays and alpha particles with various detector geometries and in different gas mixtures at pressures from 0.05 to 10 atm. The results obtained varied significantly with detector design, gas mixture and pressure, but some general features can be identified. We found that in all cases, bare MSGC'S, MGC'S, PPAC's and MICROMEGAS, the maximum achievable gain drops with rate. The addition of preamplification structures significantly increases the gain of MSGC's and MGC'S, but this gain is still rate dependent. There would seem to be a general rate-dependent effect governing the usable gain of all these detectors. We speculate on possible mechanisms for this effect, and identify a safe, spark-free, operation zone for each system (detector + preamplification structure) in the rate-gain coordinate plane.

  11. The effect of framing incentives as either losses or gains with contingency management for smoking cessation.

    PubMed

    Romanowich, Paul; Lamb, R J

    2013-04-01

    Cumulative prospect theory predicts that losses motivate behavior more than equal gains. Contingency management procedures effectively reduce drug use by placing incentives in direct competition with the drug taking behavior. Therefore, framing incentives as losses, rather than gains should decrease drug use to a greater extent, given equivalent incentives. We examined whether contingent vouchers described as either losses or gains differentially affected smoking abstinence rates. Over 5 consecutive days, participants could either gain $75 per day for verified abstinence or lose $75 per day (initial endowment=$375) for continuing to smoke. As a result, loss-framed participants were more likely to achieve at least one day of abstinence. There was a trend towards loss-framed participants reducing the amount smoked more than gain-framed participants. However, participants in the gain-framed group were more likely to maintain abstinence, once initiated. The results partially support cumulative prospect theory and suggest additional ways to initiate behavior change using incentives, outside of using larger magnitude incentives in contingency management procedures.

  12. The sweet side of inequality: how advantageous status modulates empathic response to others' gains and losses.

    PubMed

    Shen, Qiang; Jin, Jia; Ma, Qingguo

    2013-11-01

    In the past decade, considerable amounts of studies have explored the neural underpinnings of empathic response toward the positive and negative feelings of others, such as pain and social exclusion, in the field of neuroeconomics. In addition, empathic response of observing other's financial gains and losses have recently started to gain increasing attention in this interdisciplinary field. However, the effects of inequality-averse social preference on individuals' response toward other's gains and losses have not yet been clearly characterized. This work conducted an electrophysiological study with a simple gambling task to explore how inequality aversion matters in modulating neural temporal dynamics toward self and others' gains and losses using scalp-recorded event-related potentials (ERPs). The electrophysiological data demonstrated increased amplitude of P300 toward self's monetary gains and losses independent of advantageous and disadvantageous status. Intriguingly, subjects in the high pay group evoked more pronounced gain loss disparity of feedback-related negativity (FRN) amplitude toward others than themselves. Meanwhile, such a pattern was not observed among the subjects in the low pay group. Therefore, the current double dissociation results of FRN and P300 may indicate that advantageous status enhances subjects' empathic response toward others' pecuniary outcome, giving a direct electrophysiological evidence for the economic modeling on inequality aversion behavior. PMID:24004845

  13. Novel Introner-Like Elements in fungi Are Involved in Parallel Gains of Spliceosomal Introns

    PubMed Central

    Crous, Pedro W.; de Wit, Pierre J. G. M.; van der Burgt, Ate

    2015-01-01

    Spliceosomal introns are key components of the eukaryotic gene structure. Although they contributed to the emergence of eukaryotes, their origin remains elusive. In fungi, they might originate from the multiplication of invasive introns named Introner-Like Elements (ILEs). However, so far ILEs have been observed in six fungal species only, including Fulvia fulva and Dothistroma septosporum (Dothideomycetes), arguing against ILE insertion as a general mechanism for intron gain. Here, we identified novel ILEs in eight additional fungal species that are phylogenetically related to F. fulva and D. septosporum using PCR amplification with primers derived from previously identified ILEs. The ILE content appeared unique to each species, suggesting independent multiplication events. Interestingly, we identified four genes each containing two gained ILEs. By analysing intron positions in orthologues of these four genes in Ascomycota, we found that three ILEs had inserted within a 15 bp window that contains regular spliceosomal introns in other fungal species. These three positions are not the result of intron sliding because ILEs are newly gained introns. Furthermore, the alternative hypothesis of an inferred ancestral gain followed by independent losses contradicts the observed degeneration of ILEs. These observations clearly indicate three parallel intron gains in four genes that were randomly identified. Our findings suggest that parallel intron gain is a phenomenon that has been highly underestimated in ILE-containing fungi, and likely in the whole fungal kingdom. PMID:26046656

  14. Small-signal gain in a gas-loaded FEL

    SciTech Connect

    Goloviznin, V.V.; Amersfoort, P.W. van

    1995-12-31

    At present, existing FEL facilities operate in the infrared and visible ranges of wavelengths. Generation of shorter waves (in the VUV and X-ray region) is of great scientific interest, but this would require a very expensive accelerator which could provide a high-current electron beam in the GeV-range of energies. A promising way to relax requirements on electron energy by introduction of a gas into the optical cavity was proposed nearly ten years ago. For small deviations from the vacuum wavelength, the idea was confirmed in experiments performed in Stanford; however, a detailed theory of such a device is still not developed. We present an analysis of the small-signal gain in a gas-loaded free-electron laser. Multiple scattering of electrons by the atoms of the gas inside the optical cavity is shown to lead to two additional effects, as compared to the case of a vacuum FEL: a loss of coherence between different parts of the electron trajectory and an enhancement of the phase {open_quotes}jitter{close_quotes}. Both effects become increasingly important at short wavelengths and significantly reduce the small-signal gain per pass. In 1D approximation analytical expressions are obtained and numerical calculations are made to estimate beam and undulator parameters necessary for lasing in the vacuum ultraviolet. Hydrogen-filled FELs are shown to have good prospects for this at today`s technological level. To operate in the range of wavelengths 125-140 nm, an electron beam should have an energy above 50 MeV and a good quality: a normalised emittance of the order of 5{pi} mm-mrad and an energy spread below 10{sup -3}. All these parameters are achieveable with modern linacs and photoinjectors.

  15. Focal Gains of Vascular Endothelial Growth Factor A and Molecular Classification of Hepatocellular Carcinoma

    PubMed Central

    Chiang, Derek Y.; Villanueva, Augusto; Hoshida, Yujin; Peix, Judit; Newell, Philippa; Minguez, Beatriz; LeBlanc, Amanda C.; Donovan, Diana J.; Thung, Swan N.; Sole, Manel; Tovar, Victoria; Alsinet, Clara; Ramos, Alex H.; Barretina, Jordi; Roayaie, Sasan; Schwartz, Myron; Waxman, Samuel; Bruix, Jordi; Mazzaferro, Vincenzo; Ligon, Azra H.; Najfeld, Vesna; Friedman, Scott L.; Sellers, William R.; Meyerson, Matthew; Llovet, Josep M.

    2008-01-01

    Hepatocellular carcinomas (HCC) represent the third-leading cause of cancer-related deaths worldwide. The vast majority of cases arise in the context of chronic liver injury due to hepatitis B virus or hepatitis C virus infection. In order to identify genetic mechanisms of hepatocarcinogenesis, we characterized copy number alterations and gene expression profiles from the same set of tumors associated with hepatitis C virus. Most tumors harbored 1q gain, 8q gain or 8p loss, with occasional alterations in 13 additional chromosome arms. In addition to amplifications at 11q13 in 6 of 103 tumors, 4 tumors harbored focal gains at 6p21 incorporating VEGFA. Fluorescence in situ hybridization on an independent validation set of 210 tumors found 6p21 high-level gains in 14 tumors, as well as 2 tumors with 6p21 amplifications. Strikingly, this locus overlapped with copy gains in 4 of 371 lung adenocarcinomas. Overexpression of VEGFA via 6p21 gain in hepatocellular carcinomas suggested a novel, cell-nonautonomous mechanism of oncogene activation. Hierarchical clustering of gene expression among 91 of these tumors identified 5 classes, including ‘CTNNB1’, ‘proliferation’, ‘interferon-related’, and a novel class defined by polysomy of chromosome 7. These class labels were further supported by molecular data: mutations in CTNNB1 were enriched in the ‘CTNNB1’ class, while IGF1R and RPS6 phosphorylation were enriched in the ‘proliferation’ class. The enrichment of signaling pathway alterations in gene expression classes provides insights on HCC pathogenesis. Furthermore, the prevalence of VEGFA high-level gains in multiple tumor types suggests indications for clinical trials of anti-angiogenic therapies. PMID:18701503

  16. Additive lattice kirigami

    PubMed Central

    Castle, Toen; Sussman, Daniel M.; Tanis, Michael; Kamien, Randall D.

    2016-01-01

    Kirigami uses bending, folding, cutting, and pasting to create complex three-dimensional (3D) structures from a flat sheet. In the case of lattice kirigami, this cutting and rejoining introduces defects into an underlying 2D lattice in the form of points of nonzero Gaussian curvature. A set of simple rules was previously used to generate a wide variety of stepped structures; we now pare back these rules to their minimum. This allows us to describe a set of techniques that unify a wide variety of cut-and-paste actions under the rubric of lattice kirigami, including adding new material and rejoining material across arbitrary cuts in the sheet. We also explore the use of more complex lattices and the different structures that consequently arise. Regardless of the choice of lattice, creating complex structures may require multiple overlapping kirigami cuts, where subsequent cuts are not performed on a locally flat lattice. Our additive kirigami method describes such cuts, providing a simple methodology and a set of techniques to build a huge variety of complex 3D shapes. PMID:27679822

  17. Additive lattice kirigami

    PubMed Central

    Castle, Toen; Sussman, Daniel M.; Tanis, Michael; Kamien, Randall D.

    2016-01-01

    Kirigami uses bending, folding, cutting, and pasting to create complex three-dimensional (3D) structures from a flat sheet. In the case of lattice kirigami, this cutting and rejoining introduces defects into an underlying 2D lattice in the form of points of nonzero Gaussian curvature. A set of simple rules was previously used to generate a wide variety of stepped structures; we now pare back these rules to their minimum. This allows us to describe a set of techniques that unify a wide variety of cut-and-paste actions under the rubric of lattice kirigami, including adding new material and rejoining material across arbitrary cuts in the sheet. We also explore the use of more complex lattices and the different structures that consequently arise. Regardless of the choice of lattice, creating complex structures may require multiple overlapping kirigami cuts, where subsequent cuts are not performed on a locally flat lattice. Our additive kirigami method describes such cuts, providing a simple methodology and a set of techniques to build a huge variety of complex 3D shapes.

  18. Effect of a Best Practice Alert on Gestational Weight Gain, Health Services, and Pregnancy Outcomes.

    PubMed

    Lindberg, Sara M; DeBoth, Alexa; Anderson, Cynthie K

    2016-10-01

    Objective To examine whether an electronic medical record "best practice alert" previously shown to improve antenatal gestational weight gain patient education resulted in downstream effects on service delivery or patient health outcomes. Methods This study involved secondary analysis of data from an intervention to improve provider behavior surrounding gestational weight gain patient education. Data were from retrospective chart reviews of patients who received care either before (N = 333) or after (N = 268) implementation of the intervention. Pre-post comparisons and multivariable logistic regression were used to analyze downstream effects of the intervention on health outcomes and obesity-related health services while controlling for potential confounders. Results The intervention was associated with an increase in the proportion of prenatal patients who gained weight within Institute of Medicine guidelines, from 28 to 35 % (p < .05). Mean total gestational weight gain did not change, but variability decreased such that post-intervention women had weight gains closer to their gestational weight gain targets. The intervention was associated with a 94 g decrease in mean infant birth weight (p = .03), and an increase in the proportion of overweight and obese women screened for undiagnosed Type 2 diabetes before 20 weeks gestation, from 13 to 25 % (p = .01). Conclusions for Practice The electronic medical record can be leveraged to promote healthy gestational weight gain and early screening for undiagnosed Type 2 diabetes. Yet most patients still need additional support to achieve gestational weight gain within Institute of Medicine guidelines. PMID:27395382

  19. Effect of a Best Practice Alert on Gestational Weight Gain, Health Services, and Pregnancy Outcomes.

    PubMed

    Lindberg, Sara M; DeBoth, Alexa; Anderson, Cynthie K

    2016-10-01

    Objective To examine whether an electronic medical record "best practice alert" previously shown to improve antenatal gestational weight gain patient education resulted in downstream effects on service delivery or patient health outcomes. Methods This study involved secondary analysis of data from an intervention to improve provider behavior surrounding gestational weight gain patient education. Data were from retrospective chart reviews of patients who received care either before (N = 333) or after (N = 268) implementation of the intervention. Pre-post comparisons and multivariable logistic regression were used to analyze downstream effects of the intervention on health outcomes and obesity-related health services while controlling for potential confounders. Results The intervention was associated with an increase in the proportion of prenatal patients who gained weight within Institute of Medicine guidelines, from 28 to 35 % (p < .05). Mean total gestational weight gain did not change, but variability decreased such that post-intervention women had weight gains closer to their gestational weight gain targets. The intervention was associated with a 94 g decrease in mean infant birth weight (p = .03), and an increase in the proportion of overweight and obese women screened for undiagnosed Type 2 diabetes before 20 weeks gestation, from 13 to 25 % (p = .01). Conclusions for Practice The electronic medical record can be leveraged to promote healthy gestational weight gain and early screening for undiagnosed Type 2 diabetes. Yet most patients still need additional support to achieve gestational weight gain within Institute of Medicine guidelines.

  20. High gain durable anti-reflective coating

    DOEpatents

    Maghsoodi, Sina; Brophy, Brenor L.; Colson, Thomas E.; Gonsalves, Peter R.; Abrams, Ze'ev R.

    2016-07-26

    Disclosed herein are polysilsesquioxane-based anti-reflective coating (ARC) compositions, methods of preparation, and methods of deposition on a substrate. In one embodiment, the polysilsesquioxane of this disclosure is prepared in a two-step process of acid catalyzed hydrolysis of organoalkoxysilane followed by addition of tetralkoxysilane that generates silicone polymers with >40 mol % silanol based on Si-NMR. These high silanol siloxane polymers are stable and have a long shelf-life in polar organic solvents at room temperature. Also disclosed are low refractive index ARC made from these compositions with and without additives such as porogens, templates, thermal radical initiator, photo radical initiators, crosslinkers, Si--OH condensation catalyst and nano-fillers. Also disclosed are methods and apparatus for applying coatings to flat substrates including substrate pre-treatment processes, coating processes and coating curing processes including skin-curing using hot-air knives. Also disclosed are coating compositions and formulations for highly tunable, durable, highly abrasion-resistant functionalized anti-reflective coatings.

  1. Training Children in Pedestrian Safety: Distinguishing Gains in Knowledge from Gains in Safe Behavior

    PubMed Central

    McClure, Leslie A.

    2014-01-01

    Pedestrian injuries contribute greatly to child morbidity and mortality. Recent evidence suggests that training within virtual pedestrian environments may improve children’s street crossing skills, but may not convey knowledge about safety in street environments. We hypothesized that (a) children will gain pedestrian safety knowledge via videos/software/internet websites, but not when trained by virtual pedestrian environment or other strategies; (b) pedestrian safety knowledge will be associated with safe pedestrian behavior both before and after training; and (c) increases in knowledge will be associated with increases in safe behavior among children trained individually at streetside locations, but not those trained by means of other strategies. We analyzed data from a randomized controlled trial evaluating pedestrian safety training. We randomly assigned 240 children ages 7–8 to one of four training conditions: videos/software/internet, virtual reality (VR), individualized streetside instruction, or a no-contact control. Both virtual and field simulations of street crossing at 2-lane bi-directional mid-block locations assessed pedestrian behavior at baseline, post-training, and 6-month follow-up. Pedestrian knowledge was assessed orally on all three occasions. Children trained by videos/software/internet, and those trained individually, showed increased knowledge following training relative to children in the other groups (ps < 0.01). Correlations between pedestrian safety knowledge and pedestrian behavior were mostly non-significant. Correlations between change in knowledge and change in behavior from pre- to post-intervention also were non-significant, both for the full sample and within conditions. Children trained using videos/software/internet gained knowledge but did not change their behavior. Children trained individually gained in both knowledge and safer behavior. Children trained virtually gained in safer behavior but not knowledge. If VR is used

  2. Gain-of-Function Research: Ethical Analysis.

    PubMed

    Selgelid, Michael J

    2016-08-01

    Gain-of-function (GOF) research involves experimentation that aims or is expected to (and/or, perhaps, actually does) increase the transmissibility and/or virulence of pathogens. Such research, when conducted by responsible scientists, usually aims to improve understanding of disease causing agents, their interaction with human hosts, and/or their potential to cause pandemics. The ultimate objective of such research is to better inform public health and preparedness efforts and/or development of medical countermeasures. Despite these important potential benefits, GOF research (GOFR) can pose risks regarding biosecurity and biosafety. In 2014 the administration of US President Barack Obama called for a "pause" on funding (and relevant research with existing US Government funding) of GOF experiments involving influenza, SARS, and MERS viruses in particular. With announcement of this pause, the US Government launched a "deliberative process" regarding risks and benefits of GOFR to inform future funding decisions-and the US National Science Advisory Board for Biosecurity (NSABB) was tasked with making recommendations to the US Government on this matter. As part of this deliberative process the National Institutes of Health commissioned this Ethical Analysis White Paper, requesting that it provide (1) review and summary of ethical literature on GOFR, (2) identification and analysis of existing ethical and decision-making frameworks relevant to (i) the evaluation of risks and benefits of GOFR, (ii) decision-making about the conduct of GOF studies, and (iii) the development of US policy regarding GOFR (especially with respect to funding of GOFR), and (3) development of an ethical and decision-making framework that may be considered by NSABB when analyzing information provided by GOFR risk-benefit assessment, and when crafting its final recommendations (especially regarding policy decisions about funding of GOFR in particular). The ethical and decision-making framework

  3. Gain-of-Function Research: Ethical Analysis.

    PubMed

    Selgelid, Michael J

    2016-08-01

    Gain-of-function (GOF) research involves experimentation that aims or is expected to (and/or, perhaps, actually does) increase the transmissibility and/or virulence of pathogens. Such research, when conducted by responsible scientists, usually aims to improve understanding of disease causing agents, their interaction with human hosts, and/or their potential to cause pandemics. The ultimate objective of such research is to better inform public health and preparedness efforts and/or development of medical countermeasures. Despite these important potential benefits, GOF research (GOFR) can pose risks regarding biosecurity and biosafety. In 2014 the administration of US President Barack Obama called for a "pause" on funding (and relevant research with existing US Government funding) of GOF experiments involving influenza, SARS, and MERS viruses in particular. With announcement of this pause, the US Government launched a "deliberative process" regarding risks and benefits of GOFR to inform future funding decisions-and the US National Science Advisory Board for Biosecurity (NSABB) was tasked with making recommendations to the US Government on this matter. As part of this deliberative process the National Institutes of Health commissioned this Ethical Analysis White Paper, requesting that it provide (1) review and summary of ethical literature on GOFR, (2) identification and analysis of existing ethical and decision-making frameworks relevant to (i) the evaluation of risks and benefits of GOFR, (ii) decision-making about the conduct of GOF studies, and (iii) the development of US policy regarding GOFR (especially with respect to funding of GOFR), and (3) development of an ethical and decision-making framework that may be considered by NSABB when analyzing information provided by GOFR risk-benefit assessment, and when crafting its final recommendations (especially regarding policy decisions about funding of GOFR in particular). The ethical and decision-making framework

  4. Automating the evaluation of flood damages: methodology and potential gains

    NASA Astrophysics Data System (ADS)

    Eleutério, Julian; Martinez, Edgar Daniel

    2010-05-01

    The evaluation of flood damage potential consists of three main steps: assessing and processing data, combining data and calculating potential damages. The first step consists of modelling hazard and assessing vulnerability. In general, this step of the evaluation demands more time and investments than the others. The second step of the evaluation consists of combining spatial data on hazard with spatial data on vulnerability. Geographic Information System (GIS) is a fundamental tool in the realization of this step. GIS software allows the simultaneous analysis of spatial and matrix data. The third step of the evaluation consists of calculating potential damages by means of damage-functions or contingent analysis. All steps demand time and expertise. However, the last two steps must be realized several times when comparing different management scenarios. In addition, uncertainty analysis and sensitivity test are made during the second and third steps of the evaluation. The feasibility of these steps could be relevant in the choice of the extent of the evaluation. Low feasibility could lead to choosing not to evaluate uncertainty or to limit the number of scenario comparisons. Several computer models have been developed over time in order to evaluate the flood risk. GIS software is largely used to realise flood risk analysis. The software is used to combine and process different types of data, and to visualise the risk and the evaluation results. The main advantages of using a GIS in these analyses are: the possibility of "easily" realising the analyses several times, in order to compare different scenarios and study uncertainty; the generation of datasets which could be used any time in future to support territorial decision making; the possibility of adding information over time to update the dataset and make other analyses. However, these analyses require personnel specialisation and time. The use of GIS software to evaluate the flood risk requires personnel with

  5. A wide range and high speed automatic gain control

    SciTech Connect

    Tacconi, E.; Christiansen, C.

    1993-05-01

    Automatic gain control (AGC) techniques have been largely used since the beginning of electronics, but in most of the applications the dynamic response is slow compared with the carrier frequency. The problem of developing an automatic gain control with high dynamic response and wide control range simultaneously is analyzed in this work. An ideal gain control law, with the property that the total loop gain remains constant independent of the carrier amplitude, is obtained. The resulting AGC behavior is compared by computer simulations with a linear multiplier AGC. The ideal gain control law can be approximated using a transconductance amplifier. A practical circuit that has been used at CERN in the radio frequency loops of the Booster Synchrotron is presented. The circuit has high speed and 80-dB gain control range.

  6. Serotonin Affects Movement Gain Control in the Spinal Cord

    PubMed Central

    Glaser, Joshua I.; Deng, Linna; Thompson, Christopher K.; Stevenson, Ian H.; Wang, Qining; Hornby, Thomas George; Heckman, Charles J.; Kording, Konrad P.

    2014-01-01

    A fundamental challenge for the nervous system is to encode signals spanning many orders of magnitude with neurons of limited bandwidth. To meet this challenge, perceptual systems use gain control. However, whether the motor system uses an analogous mechanism is essentially unknown. Neuromodulators, such as serotonin, are prime candidates for gain control signals during force production. Serotonergic neurons project diffusely to motor pools, and, therefore, force production by one muscle should change the gain of others. Here we present behavioral and pharmaceutical evidence that serotonin modulates the input–output gain of motoneurons in humans. By selectively changing the efficacy of serotonin with drugs, we systematically modulated the amplitude of spinal reflexes. More importantly, force production in different limbs interacts systematically, as predicted by a spinal gain control mechanism. Psychophysics and pharmacology suggest that the motor system adopts gain control mechanisms, and serotonin is a primary driver for their implementation in force production. PMID:25232107

  7. Analysis of two-dimensional photonic crystal with anisotropic gain.

    PubMed

    Takigawa, Shinichi; Noda, Susumu

    2011-05-01

    Photonic modes in a two-dimensional square-lattice photonic crystal (PC) with anisotropic gain are analyzed for the first time. A plane-wave expansion method is improved to include the gain, which depends on not only the position but also the propagation direction of each plane wave. The anisotropic gain varies the photonic band structure, the near-field distributions, and the gain dispersion curves through variation in PC symmetry. Low-threshold operation of a PC laser with anisotropic-gain material such as nonpolar InGaN requires that the direction of higher gain in the material aligns along the ΓX direction of the PC. PMID:21643205

  8. The effects of neural gain on attention and learning.

    PubMed

    Eldar, Eran; Cohen, Jonathan D; Niv, Yael

    2013-08-01

    Attention is commonly thought to be manifest through local variations in neural gain. However, what would be the effects of brain-wide changes in gain? We hypothesized that global fluctuations in gain modulate the breadth of attention and the degree to which processing is focused on aspects of the environment to which one is predisposed to attend. We found that measures of pupil diameter, which are thought to track levels of locus coeruleus norepinephrine activity and neural gain, were correlated with the degree to which learning was focused on stimulus dimensions that individual human participants were more predisposed to process. In support of our interpretation of this effect in terms of global changes in gain, we found that the measured pupillary and behavioral variables were strongly correlated with global changes in the strength and clustering of functional connectivity, as brain-wide fluctuations of gain would predict. PMID:23770566

  9. Noise gain and operating temperature of quantum well infrared photodetectors

    NASA Astrophysics Data System (ADS)

    Liu, H. C.

    1992-11-01

    The difference between the noise gain associated with dark current and the photoconductive gain in quantum well infrared photodetectors is discussed in light of recent experiments. The theoretical model is based on a single key parameter: the electron trapping probability. An empirical expression for the trapping probability or, alternatively, the electron escape probability is proposed. Using the dark current, the gain, the trapping probability expressions, and the device operating temperature for achieving background limited infrared performance is discussed.

  10. Use of a photonic crystal for optical amplifier gain control

    DOEpatents

    Lin, Shawn-Yu; Fleming, James G.; El-Kady, Ihab

    2006-07-18

    An optical amplifier having a uniform gain profile uses a photonic crystal to tune the density-of-states of a gain medium so as to modify the light emission rate between atomic states. The density-of-states of the gain medium is tuned by selecting the size, shape, dielectric constant, and spacing of a plurality of microcavity defects in the photonic crystal. The optical amplifier is particularly useful for the regeneration of DWDM signals in long optical fibers.

  11. Astronomers Gain Clues About Fundamental Physics

    NASA Astrophysics Data System (ADS)

    2005-12-01

    An international team of astronomers has looked at something very big -- a distant galaxy -- to study the behavior of things very small -- atoms and molecules -- to gain vital clues about the fundamental nature of our entire Universe. The team used the National Science Foundation's Robert C. Byrd Green Bank Telescope (GBT) to test whether the laws of nature have changed over vast spans of cosmic time. The Green Bank Telescope The Robert C. Byrd Green Bank Telescope CREDIT: NRAO/AUI/NSF (Click on image for GBT gallery) "The fundamental constants of physics are expected to remain fixed across space and time; that's why they're called constants! Now, however, new theoretical models for the basic structure of matter indicate that they may change. We're testing these predictions." said Nissim Kanekar, an astronomer at the National Radio Astronomy Observatory (NRAO), in Socorro, New Mexico. So far, the scientists' measurements show no change in the constants. "We've put the most stringent limits yet on some changes in these constants, but that's not the end of the story," said Christopher Carilli, another NRAO astronomer. "This is the exciting frontier where astronomy meets particle physics," Carilli explained. The research can help answer fundamental questions about whether the basic components of matter are tiny particles or tiny vibrating strings, how many dimensions the Universe has, and the nature of "dark energy." The astronomers were looking for changes in two quantities: the ratio of the masses of the electron and the proton, and a number physicists call the fine structure constant, a combination of the electron charge, the speed of light and the Planck constant. These values, considered fundamental physical constants, once were "taken as time independent, with values given once and forever" said German particle physicist Christof Wetterich. However, Wetterich explained, "the viewpoint of modern particle theory has changed in recent years," with ideas such as

  12. Sudden gains in two psychotherapies for posttraumatic stress disorder.

    PubMed

    König, Julia; Karl, Regina; Rosner, Rita; Butollo, Willi

    2014-09-01

    We examined sudden, large, and stable shifts in symptoms from one therapy session to the next in two treatments for posttraumatic stress disorder (PTSD). Shifts in a positive direction (sudden gains) have so far been more frequently analyzed than those in a negative direction (sudden losses). We analyzed data from 102 outpatients suffering from PTSD who received either a cognitive-behavioral or a Gestalt-based intervention. Sudden gains, at 22.5%, were more frequent than sudden losses (3.9% of patients). Participants who had experienced sudden gains had lower PTSD scores at posttreatment, but not at the 6-month follow-up. As sudden losses were so rare, they were not analyzed statistically. Sudden gains accounted for 52% of overall treatment gains or 26% of overall change in a positive direction. Among very successful patients, those with sudden gains were overrepresented, but in absolute terms, there were as many patients without sudden gains in this group. There was no connection between sudden gains and type of intervention or depressive symptoms. Sudden gains and sudden losses occurred in our sample of PTSD patients, but in the light of current results, their clinical importance seems to be limited. PMID:25036539

  13. Sound pressure gain produced by the human middle ear.

    PubMed

    Kurokawa, H; Goode, R L

    1995-10-01

    The acoustic function of the middle ear is to match sound passing from the low impedance of air to the high impedance of cochlear fluid. Little information is available on the actual middle ear pressure gain in human beings. This article describes experiments on middle ear pressure gain in six fresh human temporal bones. Stapes footplate displacement and phase were measured with a laser Doppler vibrometer before and after removal of the tympanic membrane, malleus, and incus. Acoustic insulation of the round window with clay was performed. Umbo displacement was also measured before tympanic membrane removal to assess baseline tympanic membrane function. The middle ear has its major gain in the lower frequencies, with a peak near 0.9 kHz. The mean gain was 23.0 dB below 1.0 kHz, the resonant frequency of the middle ear; the mean peak gain was 26.6 dB. Above 1.0 kHz, the second pressure gain decreased at a rate of -8.6 dB/octave, with a mean gain of 6.5 dB at 4.0 kHz. Only a small amount of gain was present above 7.0 kHz. Significant individual differences in pressure gain were found between ears that appeared related to variations in tympanic membrane function and not to variations in cochlear impedance. PMID:7567003

  14. Stability, gain, and robustness in quantum feedback networks

    SciTech Connect

    D'Helon, C.; James, M. R.

    2006-05-15

    In this paper we are concerned with the problem of stability for quantum feedback networks. We demonstrate in the context of quantum optics how stability of quantum feedback networks can be guaranteed using only simple gain inequalities for network components and algebraic relationships determined by the network. Quantum feedback networks are shown to be stable if the loop gain is less than one--this is an extension of the famous small gain theorem of classical control theory. We illustrate the simplicity and power of the small gain approach with applications to important problems of robust stability and robust stabilization.

  15. Modes of unstable resonators with a saturable gain guide.

    PubMed

    Denchev, O; Kurtev, S; Petrov, P

    2001-02-20

    We investigate theoretically gain-guided modes in unstable resonators with a uniformly reflective mirror in the area of highly efficient steady-state lasers, where the gain saturation is the main efficiency factorly. We achieved self-consistent Hermite-Gaussian modes at significant gain saturation as well as the connection of the mode's scaling factor and mode amplitude coefficients with the system parameters by using complex paraxial wave optics. A new stabilization mechanism, saturation guiding, works together with gain guiding in unstable resonators. We obtained more actual results for mode generation and selection by integrating the laser rate equation. PMID:18357074

  16. Diverse women's beliefs about weight gain in pregnancy.

    PubMed

    Groth, Susan W; Kearney, Margaret H

    2009-01-01

    This research was conducted to describe ethnically diverse new mothers' perceptions of gestational weight gain. Forty-nine low-income women of diverse racial and ethnic origins who birthed an infant within the past year completed a semistructured interview in a pediatric clinic waiting room. The interviews were designed to elicit views on gestational weight gain, including expectations and perceived consequences. Data were analyzed using content analysis techniques. Women believed that others like themselves were concerned about pregnancy weight gain. Many focused on the effects of insufficient pregnancy weight gain on the infant but were not aware of the infant risks of excessive gain. Several had inaccurate knowledge of appropriate gestational weight gain, and many suggested an amount below the current recommendations. One-third of the women believed women will weigh more following pregnancy, yet others assumed that even with excessive weight gain there would be a return to prepregnant weight following pregnancy. Pregnancy-related weight gain is disturbing to women. Health care providers have the opportunity to intervene by acknowledging these concerns and providing information and support to help women make positive choices and achieve appropriate weight gain. PMID:19879517

  17. Physician unionization efforts gain momentum, support.

    PubMed

    Keating, G C

    1999-11-01

    Physicians increasingly are assuming the status of employees in healthcare organizations. Physicians also are seeing restrictions imposed on their practices by healthcare organizations seeking to control costs of care delivery. These trends have led a growing number of physicians to attempt to organize into unions. Obstacles to physician unionization efforts have included Federal antitrust laws that prohibit physicians from organizing, as well as physician reluctance to engage in organized activities they see as antithetical to their professional duties (e.g., strikes). In addition, physicians' attempts to unionize frequently have failed due to provisions of the National Labor Relations Act, which authorize collective bargaining only among individuals designated as "employees." Physicians seeking to form unions often are thwarted by the argument that they are not employees, but rather students, independent contractors, or supervisors, and therefore not entitled to protection under the act. Nonetheless, a number of recent developments, such as the American Medical Association's decision to endorse unionization by physicians and the National Labor Relations Board's decision that attending physicians should be regarded as employees, not supervisors, are creating a climate more conducive to physician unionization in the United States.

  18. Exploring the willingness to pay for a quality-adjusted life-year in the state of Penang, Malaysia

    PubMed Central

    Shafie, Asrul Akmal; Lim, Yen Wei; Chua, Gin Nie; Hassali, Mohammed Azmi Ahmad

    2014-01-01

    Introduction The incremental cost-effectiveness ratio (ICER) is typically compared with a reference value to support the cost-effectiveness of a decision. One method for estimating this value is to estimate the willingness-to-pay (WTP) for a quality-adjusted life-year (QALY). This study was conducted to explore the WTP for a QALY in the Malaysian population. Methods A cross-sectional, contingent valuation study was conducted in Penang, Malaysia. Respondents were selected from randomly chosen geographical grids of Penang. Respondents’ sociodemographic information, qualities of life, and WTP for one additional QALY were collected using predesigned questionnaires in face-to-face interviews. WTP values were elicited using a double-bound dichotomous choice via a bidding game approach. The Heckman selection model was applied to the analysis of the mean WTP/QALY values, where the “protest zero” values, which may contribute to selection bias, were excluded. Results The mean value of WTP for an additional QALY gained was estimated to be MYR (Malaysian Ringgit) 29,080 (~USD 9,000). Key factors that affected the WTP include ethnicity and estimated monthly household income. Conclusion The study findings suggested that the cost-effectiveness threshold value as studied in Penang, Malaysia was estimated to be MYR 29,080. PMID:25364267

  19. Gaining the necessary geologic, hydrologic, and geochemical understanding for additional brackish groundwater development, coastal San Diego, California, USA

    USGS Publications Warehouse

    Danskin, Wesley R.

    2012-01-01

    Local water agencies and the United States Geological Survey are using a combination of techniques to better understand the scant freshwater resources and the much more abundant brackish resources in coastal San Diego, California, USA. Techniques include installation of multiple-depth monitoring well sites; geologic and paleontological analysis of drill cuttings; geophysical logging to identify formations and possible seawater intrusion; sampling of pore-water obtained from cores; analysis of chemical constituents including trace elements and isotopes; and use of scoping models including a three-dimensional geologic framework model, rainfall-runoff model, regional groundwater flow model, and coastal density-dependent groundwater flow model. Results show that most fresh groundwater was recharged during the last glacial period and that the coastal aquifer has had recurring intrusions of fresh and saline water. These intrusions disguise the source, flowpaths, and history of ground water near the coast. The flow system includes a freshwater lens resting on brackish water; a 100-meter-thick flowtube of freshwater discharging under brackish estuarine water and above highly saline water; and broad areas of fine-grained coastal sediment filled with fairly uniform brackish water. Stable isotopes of hydrogen and oxygen indicate the recharged water flows through many kilometers of fractured crystalline rock before entering the narrow coastal aquifer.

  20. Gains to species diversity in organically farmed fields are not propagated at the farm level.

    PubMed

    Schneider, Manuel K; Lüscher, Gisela; Jeanneret, Philippe; Arndorfer, Michaela; Ammari, Youssef; Bailey, Debra; Balázs, Katalin; Báldi, András; Choisis, Jean-Philippe; Dennis, Peter; Eiter, Sebastian; Fjellstad, Wendy; Fraser, Mariecia D; Frank, Thomas; Friedel, Jürgen K; Garchi, Salah; Geijzendorffer, Ilse R; Gomiero, Tiziano; Gonzalez-Bornay, Guillermo; Hector, Andy; Jerkovich, Gergely; Jongman, Rob H G; Kakudidi, Esezah; Kainz, Max; Kovács-Hostyánszki, Anikó; Moreno, Gerardo; Nkwiine, Charles; Opio, Julius; Oschatz, Marie-Louise; Paoletti, Maurizio G; Pointereau, Philippe; Pulido, Fernando J; Sarthou, Jean-Pierre; Siebrecht, Norman; Sommaggio, Daniele; Turnbull, Lindsay A; Wolfrum, Sebastian; Herzog, Felix

    2014-06-24

    Organic farming is promoted to reduce environmental impacts of agriculture, but surprisingly little is known about its effects at the farm level, the primary unit of decision making. Here we report the effects of organic farming on species diversity at the field, farm and regional levels by sampling plants, earthworms, spiders and bees in 1470 fields of 205 randomly selected organic and nonorganic farms in twelve European and African regions. Species richness is, on average, 10.5% higher in organic than nonorganic production fields, with highest gains in intensive arable fields (around +45%). Gains to species richness are partly caused by higher organism abundance and are common in plants and bees but intermittent in earthworms and spiders. Average gains are marginal +4.6% at the farm and +3.1% at the regional level, even in intensive arable regions. Additional, targeted measures are therefore needed to fulfil the commitment of organic farming to benefit farmland biodiversity.

  1. Gains to species diversity in organically farmed fields are not propagated at the farm level.

    PubMed

    Schneider, Manuel K; Lüscher, Gisela; Jeanneret, Philippe; Arndorfer, Michaela; Ammari, Youssef; Bailey, Debra; Balázs, Katalin; Báldi, András; Choisis, Jean-Philippe; Dennis, Peter; Eiter, Sebastian; Fjellstad, Wendy; Fraser, Mariecia D; Frank, Thomas; Friedel, Jürgen K; Garchi, Salah; Geijzendorffer, Ilse R; Gomiero, Tiziano; Gonzalez-Bornay, Guillermo; Hector, Andy; Jerkovich, Gergely; Jongman, Rob H G; Kakudidi, Esezah; Kainz, Max; Kovács-Hostyánszki, Anikó; Moreno, Gerardo; Nkwiine, Charles; Opio, Julius; Oschatz, Marie-Louise; Paoletti, Maurizio G; Pointereau, Philippe; Pulido, Fernando J; Sarthou, Jean-Pierre; Siebrecht, Norman; Sommaggio, Daniele; Turnbull, Lindsay A; Wolfrum, Sebastian; Herzog, Felix

    2014-01-01

    Organic farming is promoted to reduce environmental impacts of agriculture, but surprisingly little is known about its effects at the farm level, the primary unit of decision making. Here we report the effects of organic farming on species diversity at the field, farm and regional levels by sampling plants, earthworms, spiders and bees in 1470 fields of 205 randomly selected organic and nonorganic farms in twelve European and African regions. Species richness is, on average, 10.5% higher in organic than nonorganic production fields, with highest gains in intensive arable fields (around +45%). Gains to species richness are partly caused by higher organism abundance and are common in plants and bees but intermittent in earthworms and spiders. Average gains are marginal +4.6% at the farm and +3.1% at the regional level, even in intensive arable regions. Additional, targeted measures are therefore needed to fulfil the commitment of organic farming to benefit farmland biodiversity. PMID:24958283

  2. Development of low read noise high conversion gain CMOS image sensor for photon counting level imaging

    NASA Astrophysics Data System (ADS)

    Seo, Min-Woong; Kawahito, Shoji; Kagawa, Keiichiro; Yasutomi, Keita

    2016-05-01

    A CMOS image sensor with deep sub-electron read noise and high pixel conversion gain has been developed. Its performance is recognized through image outputs from an area image sensor, confirming the capability of photoelectroncounting- level imaging. To achieve high conversion gain, the proposed pixel has special structures to reduce the parasitic capacitances around FD node. As a result, the pixel conversion gain is increased due to the optimized FD node capacitance, and the noise performance is also improved by removing two noise sources from power supply. For the first time, high contrast images from the reset-gate-less CMOS image sensor, with less than 0.3e- rms noise level, have been generated at an extremely low light level of a few electrons per pixel. In addition, the photon-counting capability of the developed CMOS imager is demonstrated by a measurement, photoelectron-counting histogram (PCH).

  3. Short inter-pregnancy intervals, parity, excessive pregnancy weight gain and risk of maternal obesity.

    PubMed

    Davis, Esa M; Babineau, Denise C; Wang, Xuelei; Zyzanski, Stephen; Abrams, Barbara; Bodnar, Lisa M; Horwitz, Ralph I

    2014-04-01

    To investigate the relationship among parity, length of the inter-pregnancy intervals and excessive pregnancy weight gain in the first pregnancy and the risk of obesity. Using a prospective cohort study of 3,422 non-obese, non-pregnant US women aged 14-22 years at baseline, adjusted Cox models were used to estimate the association among parity, inter-pregnancy intervals, and excessive pregnancy weight gain in the first pregnancy and the relative hazard rate (HR) of obesity. Compared to nulliparous women, primiparous women with excessive pregnancy weight gain in the first pregnancy had a HR of obesity of 1.79 (95% CI 1.40, 2.29); no significant difference was seen between primiparous without excessive pregnancy weight gain in the first pregnancy and nulliparous women. Among women with the same pregnancy weight gain in the first pregnancy and the same number of inter-pregnancy intervals (12 and 18 months or ≥18 months), the HR of obesity increased 2.43-fold (95% CI 1.21, 4.89; p = 0.01) for every additional inter-pregnancy interval of <12 months; no significant association was seen for longer inter-pregnancy intervals. Among women with the same parity and inter-pregnancy interval pattern, women with excessive pregnancy weight gain in the first pregnancy had an HR of obesity 2.41 times higher (95% CI 1.81, 3.21; p < 0.001) than women without. Primiparous and nulliparous women had similar obesity risk unless the primiparous women had excessive pregnancy weight gain in the first pregnancy, then their risk of obesity was greater. Multiparous women with the same excessive pregnancy weight gain in the first pregnancy and at least one additional short inter-pregnancy interval had a significant risk of obesity after childbirth. Perinatal interventions that prevent excessive pregnancy weight gain in the first pregnancy or lengthen the inter-pregnancy interval are necessary for reducing maternal obesity.

  4. Online gain update for manual following response accompanied by gaze shift during arm reaching.

    PubMed

    Abekawa, Naotoshi; Gomi, Hiroaki

    2015-02-15

    To capture objects by hand, online motor corrections are required to compensate for self-body movements. Recent studies have shown that background visual motion, usually caused by body movement, plays a significant role in such online corrections. Visual motion applied during a reaching movement induces a rapid and automatic manual following response (MFR) in the direction of the visual motion. Importantly, the MFR amplitude is modulated by the gaze direction relative to the reach target location (i.e., foveal or peripheral reaching). That is, the brain specifies the adequate visuomotor gain for an online controller based on gaze-reach coordination. However, the time or state point at which the brain specifies this visuomotor gain remains unclear. More specifically, does the gain change occur even during the execution of reaching? In the present study, we measured MFR amplitudes during a task in which the participant performed a saccadic eye movement that altered the gaze-reach coordination during reaching. The results indicate that the MFR amplitude immediately after the saccade termination changed according to the new gaze-reach coordination, suggesting a flexible online updating of the MFR gain during reaching. An additional experiment showed that this gain updating mostly started before the saccade terminated. Therefore, the MFR gain updating process would be triggered by an ocular command related to saccade planning or execution based on forthcoming changes in the gaze-reach coordination. Our findings suggest that the brain flexibly updates the visuomotor gain for an online controller even during reaching movements based on continuous monitoring of the gaze-reach coordination. PMID:25429112

  5. Hybrid discrete choice models: Gained insights versus increasing effort.

    PubMed

    Mariel, Petr; Meyerhoff, Jürgen

    2016-10-15

    Hybrid choice models expand the standard models in discrete choice modelling by incorporating psychological factors as latent variables. They could therefore provide further insights into choice processes and underlying taste heterogeneity but the costs of estimating these models often significantly increase. This paper aims at comparing the results from a hybrid choice model and a classical random parameter logit. Point of departure for this analysis is whether researchers and practitioners should add hybrid choice models to their suite of models routinely estimated. Our comparison reveals, in line with the few prior studies, that hybrid models gain in efficiency by the inclusion of additional information. The use of one of the two proposed approaches, however, depends on the objective of the analysis. If disentangling preference heterogeneity is most important, hybrid model seems to be preferable. If the focus is on predictive power, a standard random parameter logit model might be the better choice. Finally, we give recommendations for an adequate use of hybrid choice models based on known principles of elementary scientific inference. PMID:27310534

  6. Hybrid discrete choice models: Gained insights versus increasing effort.

    PubMed

    Mariel, Petr; Meyerhoff, Jürgen

    2016-10-15

    Hybrid choice models expand the standard models in discrete choice modelling by incorporating psychological factors as latent variables. They could therefore provide further insights into choice processes and underlying taste heterogeneity but the costs of estimating these models often significantly increase. This paper aims at comparing the results from a hybrid choice model and a classical random parameter logit. Point of departure for this analysis is whether researchers and practitioners should add hybrid choice models to their suite of models routinely estimated. Our comparison reveals, in line with the few prior studies, that hybrid models gain in efficiency by the inclusion of additional information. The use of one of the two proposed approaches, however, depends on the objective of the analysis. If disentangling preference heterogeneity is most important, hybrid model seems to be preferable. If the focus is on predictive power, a standard random parameter logit model might be the better choice. Finally, we give recommendations for an adequate use of hybrid choice models based on known principles of elementary scientific inference.

  7. Difficult communication: compliance-gaining strategies of organ procurement coordinators.

    PubMed

    Anker, Ashley E; Feeley, Thomas Hugh

    2011-04-01

    Organ procurement coordinators (OPCs) face a formidable communication task when making familial requests for consent to organ donation, because they must provide social support for grieving family members while seeking compliance to the donation request. Structured interviews were conducted with 102 OPCs, representing 16 organ procurement organizations (OPOs) (27.6% of national organizations) across the United States. Responses were transcribed and content-analyzed along four domain areas: (a) establishing credibility, (b) message strategies, (c) timing/setting of requests, and (d) adaptation of messages to diverse families. OPO conversion rates were used as a criterion factor for OPCs' persuasive communication success and regressed onto self-reported strategy use. Results indicate message strategies varied at the OPC level of analysis and 7 techniques significantly predicted 32% of the variance in conversion rates. Two strategies (i.e., gaining early intervention, approaching with additional support) positively influenced conversion rates, whereas 5 strategies (e.g., discussing benefits as a persuasive strategy, emphasizing the need for donation in particular racial/ethnic groups) negatively influenced conversion rates. Future research is recommended to validate the study findings toward the goal of improving OPCs' communication strategies.

  8. Distribution of lifespan gain from primary prevention intervention

    PubMed Central

    Finegold, Judith A; Shun-Shin, Matthew J; Cole, Graham D; Zaman, Saman; Maznyczka, Annette; Zaman, Sameer; Al-Lamee, Rasha; Ye, Siqin; Francis, Darrel P

    2016-01-01

    Objective When advising patients about possible initiation of primary prevention treatment, clinicians currently do not have information on expected impact on lifespan, nor how much this increment differs between individuals. Methods First, UK cardiovascular and non-cardiovascular mortality data were used to calculate the mean lifespan gain from an intervention (such as a statin) that reduces cardiovascular mortality by 30%. Second, a new method was developed to calculate the probability distribution of lifespan gain. Third, we performed a survey in three UK cities on 11 days between May–June 2014 involving 396 participants (mean age 40 years, 55% male) to assess how individuals evaluate potential benefit from primary prevention therapies. Results Among numerous identical patients, the lifespan gain, from an intervention that reduces cardiovascular mortality by 30%, is concentrated within an unpredictable minority. For example, men aged 50 years with national average cardiovascular risk have mean lifespan gain of 7 months. However, 93% of these identical individuals gain no lifespan, while the remaining 7% gain a mean of 99 months. Many survey respondents preferred a chance of large lifespan gain to the equivalent life expectancy gain given as certainty. Indeed, 33% preferred a 2% probability of 10 years to fivefold more gain, expressed as certainty of 1 year. Conclusions People who gain lifespan from preventative therapy gain far more than the average for their risk stratum, even if perfectly defined. This may be important in patient decision-making. Looking beyond mortality reduction alone from preventative therapy, the benefits are likely to be even larger. PMID:27042321

  9. Modest Visceral Fat Gain Causes Endothelial Dysfunction In Healthy Humans

    PubMed Central

    Romero-Corral, Abel; Sert-Kuniyoshi, Fatima H.; Sierra-Johnson, Justo; Orban, Marek; Gami, Apoor; Davison, Diane; Singh, Prachi; Pusalavidyasagar, Snigdha; Huyber, Christine; Votruba, Susanne; Lopez-Jimenez, Francisco; Jensen, Michael D.; Somers, Virend K.

    2014-01-01

    Objective This study sought to determine the impact of fat gain and its distribution on endothelial function in lean healthy humans. Background Endothelial dysfunction has been identified as an independent predictor of cardiovascular events. Whether fat gain impairs endothelial function is unknown. Methods A randomized controlled study to assess the effects of fat gain on endothelial function. We recruited 43 normal weight healthy volunteers (mean age 29 years; 18 women). Subjects were assigned to gain weight (approximately 4 kg) (n=35) or to maintain weight (n=8). Endothelial function (brachial artery flow mediated dilation -FMD) was measured at baseline, after fat gain (8 weeks) and after weight loss (16 weeks) for fat-gainers and at baseline and follow-up (8 weeks) for weight-maintainers. Body composition was measured by DXA and abdominal CT scans. Results After an average weight gain of 4.1 kg, fat-gainers significantly increased their total, visceral and subcutaneous fat. Blood pressure and overnight polysomnography did not change after fat gain or loss. FMD remained unchanged in weight-maintainers. FMD decreased in fat-gainers (9.1 ± 3% vs. 7.8 ± 3.2%, p =0.003), but recovered to baseline when subjects shed the gained weight. There was a significant correlation between the decrease in FMD and the increase in visceral fat gain (rho = −0.42, p=0.004), but not with subcutaneous fat gain (rho = −0.22, p=0.15). Conclusions In normal weight healthy young subjects, modest fat gain results in impaired endothelial function, even in the absence of changes in blood pressure. Endothelial function recovers after weight loss. Increased visceral rather than subcutaneous fat predicts endothelial dysfunction. PMID:20705223

  10. Gain compensation technique by bias correction in arrays of Silicon Photomultipliers using fully differential fast shaper

    NASA Astrophysics Data System (ADS)

    Baszczyk, M.; Dorosz, P.; Glab, S.; Kucewicz, W.; Mik, L.; Sapor, M.

    2016-07-01

    Proposed algorithm compensates the gain by changing the bias voltage of Silicon Photomultipliers (SiPM). The signal from SiPM is amplified in fully differential preamplifier then is formed in time by the fully differential fast shaper. The compensation method was tested with four channels common cathode multi-pixel photon counter from Hamamatsu. The measurement system requires only one high voltage power supply. The polarization voltage is adjusted individually in each channel indirectly by tuning the output common mode voltage (VOCM) of fully differential amplifier. The changes of VOCM affect the input voltage through the feedback network. Actual gain of the SiPM is calculated by measuring the mean amplitude of the signal resulting from detection of single photoelectron. The VOCM is adjusted by DAC so as to reach the desired value of gain by each channel individually. The advantage of the algorithm is the possibility to set the bias of each SiPM in the array independently so they all could operate in very similar conditions (have similar gain and dark count rate). The algorithm can compensate the variations of gain of SiPM by using thermally generated pulses. There is no need to use additional current to voltage conversion which could introduce extra noises.

  11. Multimodal Pilot Behavior in Multi-Axis Tracking Tasks with Time-Varying Motion Cueing Gains

    NASA Technical Reports Server (NTRS)

    Zaal, P. M. T; Pool, D. M.

    2014-01-01

    In a large number of motion-base simulators, adaptive motion filters are utilized to maximize the use of the available motion envelope of the motion system. However, not much is known about how the time-varying characteristics of such adaptive filters affect pilots when performing manual aircraft control. This paper presents the results of a study investigating the effects of time-varying motion filter gains on pilot control behavior and performance. An experiment was performed in a motion-base simulator where participants performed a simultaneous roll and pitch tracking task, while the roll and/or pitch motion filter gains changed over time. Results indicate that performance increases over time with increasing motion gains. This increase is a result of a time-varying adaptation of pilots' equalization dynamics, characterized by increased visual and motion response gains and decreased visual lead time constants. Opposite trends are found for decreasing motion filter gains. Even though the trends in both controlled axes are found to be largely the same, effects are less significant in roll. In addition, results indicate minor cross-coupling effects between pitch and roll, where a cueing variation in one axis affects the behavior adopted in the other axis.

  12. Biodiversity gains from efficient use of private sponsorship for flagship species conservation.

    PubMed

    Bennett, Joseph R; Maloney, Richard; Possingham, Hugh P

    2015-04-22

    To address the global extinction crisis, both efficient use of existing conservation funding and new sources of funding are vital. Private sponsorship of charismatic 'flagship' species conservation represents an important source of new funding, but has been criticized as being inefficient. However, the ancillary benefits of privately sponsored flagship species conservation via actions benefiting other species have not been quantified, nor have the benefits of incorporating such sponsorship into objective prioritization protocols. Here, we use a comprehensive dataset of conservation actions for the 700 most threatened species in New Zealand to examine the potential biodiversity gains from national private flagship species sponsorship programmes. We find that private funding for flagship species can clearly result in additional species and phylogenetic diversity conserved, via conservation actions shared with other species. When private flagship species funding is incorporated into a prioritization protocol to preferentially sponsor shared actions, expected gains can be more than doubled. However, these gains are consistently smaller than expected gains in a hypothetical scenario where private funding could be optimally allocated among all threatened species. We recommend integrating private sponsorship of flagship species into objective prioritization protocols to sponsor efficient actions that maximize biodiversity gains, or wherever possible, encouraging private donations for broader biodiversity goals.

  13. Biodiversity gains from efficient use of private sponsorship for flagship species conservation

    PubMed Central

    Bennett, Joseph R.; Maloney, Richard; Possingham, Hugh P.

    2015-01-01

    To address the global extinction crisis, both efficient use of existing conservation funding and new sources of funding are vital. Private sponsorship of charismatic ‘flagship’ species conservation represents an important source of new funding, but has been criticized as being inefficient. However, the ancillary benefits of privately sponsored flagship species conservation via actions benefiting other species have not been quantified, nor have the benefits of incorporating such sponsorship into objective prioritization protocols. Here, we use a comprehensive dataset of conservation actions for the 700 most threatened species in New Zealand to examine the potential biodiversity gains from national private flagship species sponsorship programmes. We find that private funding for flagship species can clearly result in additional species and phylogenetic diversity conserved, via conservation actions shared with other species. When private flagship species funding is incorporated into a prioritization protocol to preferentially sponsor shared actions, expected gains can be more than doubled. However, these gains are consistently smaller than expected gains in a hypothetical scenario where private funding could be optimally allocated among all threatened species. We recommend integrating private sponsorship of flagship species into objective prioritization protocols to sponsor efficient actions that maximize biodiversity gains, or wherever possible, encouraging private donations for broader biodiversity goals. PMID:25808885

  14. On controllability of neuronal networks with constraints on the average of control gains.

    PubMed

    Tang, Yang; Wang, Zidong; Gao, Huijun; Qiao, Hong; Kurths, Jürgen

    2014-12-01

    Control gains play an important role in the control of a natural or a technical system since they reflect how much resource is required to optimize a certain control objective. This paper is concerned with the controllability of neuronal networks with constraints on the average value of the control gains injected in driver nodes, which are in accordance with engineering and biological backgrounds. In order to deal with the constraints on control gains, the controllability problem is transformed into a constrained optimization problem (COP). The introduction of the constraints on the control gains unavoidably leads to substantial difficulty in finding feasible as well as refining solutions. As such, a modified dynamic hybrid framework (MDyHF) is developed to solve this COP, based on an adaptive differential evolution and the concept of Pareto dominance. By comparing with statistical methods and several recently reported constrained optimization evolutionary algorithms (COEAs), we show that our proposed MDyHF is competitive and promising in studying the controllability of neuronal networks. Based on the MDyHF, we proceed to show the controlling regions under different levels of constraints. It is revealed that we should allocate the control gains economically when strong constraints are considered. In addition, it is found that as the constraints become more restrictive, the driver nodes are more likely to be selected from the nodes with a large degree. The results and methods presented in this paper will provide useful insights into developing new techniques to control a realistic complex network efficiently.

  15. Cost-effectiveness of heat and moisture exchangers compared to usual care for pulmonary rehabilitation after total laryngectomy in Poland.

    PubMed

    Retèl, Valesca P; van den Boer, Cindy; Steuten, Lotte M G; Okła, Sławomir; Hilgers, Frans J; van den Brekel, Michiel W

    2015-09-01

    The beneficial physical and psychosocial effects of heat and moisture exchangers (HMEs) for pulmonary rehabilitation of laryngectomy patients are well evidenced. However, cost-effectiveness in terms of costs per additional quality-adjusted life years (QALYs) has not yet been investigated. Therefore, a model-based cost-effectiveness analysis of using HMEs versus usual care (UC) (including stoma covers, suction system and/or external humidifier) for patients after laryngectomy was performed. Primary outcomes were costs, QALYs and incremental cost-effectiveness ratio (ICER). Secondary outcomes were pulmonary infections, and sleeping problems. The analysis was performed from a health care perspective of Poland, using a time horizon of 10 years and cycle length of 1 year. Transition probabilities were derived from various sources, amongst others a Polish randomized clinical trial. Quality of life data was derived from an Italian study on similar patients. Data on frequencies and mortality-related tracheobronchitis and/or pneumonia were derived from a Europe-wide survey amongst head and neck cancer experts. Substantial differences in quality-adjusted survival between the use of HMEs (3.63 QALYs) versus UC (2.95 QALYs) were observed. Total health care costs/patient were 39,553 PLN (9465 Euro) for the HME strategy and 4889 PLN (1168 Euro) for the UC strategy. HME use resulted in fewer pulmonary infections, and less sleeping problems. We could conclude that given the Polish threshold of 99,000 PLN/QALY, using HMEs is cost-effective compared to UC, resulting in 51,326 PLN/QALY (12,264 Euro/QALY) gained for patients after total laryngectomy. For the hospital period alone (2 weeks), HMEs were cost-saving: less costly and more effective.

  16. 24 CFR 3280.507 - Comfort heat gain.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 24 Housing and Urban Development 5 2011-04-01 2011-04-01 false Comfort heat gain. 3280.507 Section... DEVELOPMENT MANUFACTURED HOME CONSTRUCTION AND SAFETY STANDARDS Thermal Protection § 3280.507 Comfort heat... part. (a) Transmission heat gains. Homes complying with this section shall meet the minimum heat...

  17. 24 CFR 3280.507 - Comfort heat gain.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 24 Housing and Urban Development 5 2013-04-01 2013-04-01 false Comfort heat gain. 3280.507 Section... DEVELOPMENT MANUFACTURED HOME CONSTRUCTION AND SAFETY STANDARDS Thermal Protection § 3280.507 Comfort heat... part. (a) Transmission heat gains. Homes complying with this section shall meet the minimum heat...

  18. 24 CFR 3280.507 - Comfort heat gain.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 24 Housing and Urban Development 5 2014-04-01 2014-04-01 false Comfort heat gain. 3280.507 Section... DEVELOPMENT MANUFACTURED HOME CONSTRUCTION AND SAFETY STANDARDS Thermal Protection § 3280.507 Comfort heat... part. (a) Transmission heat gains. Homes complying with this section shall meet the minimum heat...

  19. 24 CFR 3280.507 - Comfort heat gain.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 24 Housing and Urban Development 5 2012-04-01 2012-04-01 false Comfort heat gain. 3280.507 Section... DEVELOPMENT MANUFACTURED HOME CONSTRUCTION AND SAFETY STANDARDS Thermal Protection § 3280.507 Comfort heat... part. (a) Transmission heat gains. Homes complying with this section shall meet the minimum heat...

  20. Weight gain associated with taking psychotropic medication: an integrative review.

    PubMed

    McCloughen, Andrea; Foster, Kim

    2011-06-01

    People with serious mental illness have higher morbidity and mortality rates than general populations, and overweight/obesity-related conditions are prevalent. Psychotropic medications are a primary factor in significant weight gain. Adolescents and young adults, particularly those with first-episode psychoses taking atypical antipsychotics, are susceptible to weight gain. This paper reports findings from an integrative review of research investigating the impact and treatment of psychotropic-induced weight gain. Four databases were searched, yielding 522 papers. From these and hand-searched papers, 36 research reports were systematically classified and analysed. The review revealed people experiencing psychotropic-induced weight gain perceive it as distressing. It impacts on quality of life and contributes to treatment non-adherence. Weight management and prevention strategies have primarily targeted adults with existing/chronic illness rather than those with first-episode psychoses and/or drug naiveté. Single and multimodal interventions to prevent or manage weight gain produced comparable, modest results. This review highlights that the effectiveness of weight management interventions is not fully known, and there is a lack of information regarding weight gain prevention for young people taking psychotropics. Future research directions include exploring the needs of young people regarding psychotropic-related weight gain and long-term, follow-up studies of lifestyle interventions to prevent psychotropic-related weight gain.

  1. The Causes of and Gains from Intertemporal Trade

    ERIC Educational Resources Information Center

    Craighead, William D.; Miller, Norman C.

    2010-01-01

    The authors show how the causes of and the gains from current account imbalances can be integrated into undergraduate economics courses using the same pedagogical tools that are used to explain comparative advantage and the gains from trade. A nonzero current account provides a mechanism for intertemporal trade, and a country has a comparative…

  2. A variable-gain output feedback control design methodology

    NASA Technical Reports Server (NTRS)

    Halyo, Nesim; Moerder, Daniel D.; Broussard, John R.; Taylor, Deborah B.

    1989-01-01

    A digital control system design technique is developed in which the control system gain matrix varies with the plant operating point parameters. The design technique is obtained by formulating the problem as an optimal stochastic output feedback control law with variable gains. This approach provides a control theory framework within which the operating range of a control law can be significantly extended. Furthermore, the approach avoids the major shortcomings of the conventional gain-scheduling techniques. The optimal variable gain output feedback control problem is solved by embedding the Multi-Configuration Control (MCC) problem, previously solved at ICS. An algorithm to compute the optimal variable gain output feedback control gain matrices is developed. The algorithm is a modified version of the MCC algorithm improved so as to handle the large dimensionality which arises particularly in variable-gain control problems. The design methodology developed is applied to a reconfigurable aircraft control problem. A variable-gain output feedback control problem was formulated to design a flight control law for an AFTI F-16 aircraft which can automatically reconfigure its control strategy to accommodate failures in the horizontal tail control surface. Simulations of the closed-loop reconfigurable system show that the approach produces a control design which can accommodate such failures with relative ease. The technique can be applied to many other problems including sensor failure accommodation, mode switching control laws and super agility.

  3. Enhanced Decoding for the Galileo Low-Gain Antenna Mission

    NASA Technical Reports Server (NTRS)

    Dolinar, S.; Belongie, M.

    1994-01-01

    Due to a malfunctioning high-gain antenna, the Galileo spacecraft is transmitting all its data through a low-gain antenna, and the data rate will seldom exceed 100 bits per second during its two-year tour of Jupiter's satellites.

  4. Focal-Plane Analysis For Calculating Antenna Gain

    NASA Technical Reports Server (NTRS)

    Cramer, Paul W.; Imbriale, William A.; Rengarajan, Sembiam R.

    1996-01-01

    Improved method devised for calculating gain of antenna system comprising main reflector and array of feed elements. Method involves much less computation; important advantage when necessary to compute gains repeatedly, with slight variations in design at each iteration, in effort to find optimum design.

  5. Psychological Adjustment of Adolescents Attempting to Lose or Gain Weight.

    ERIC Educational Resources Information Center

    Rosen, James C.; And Others

    1987-01-01

    Compared the psychological adjustment of high school boys and girls trying to reduce or gain weight. Reducers of both sexes and male gainers exhibited lower physical self-esteem. Girls trying to change weight in either direction showed depression and lower global self-esteem. Girls' decisions to gain or lose weight were influenced by psychological…

  6. 26 CFR 1.1202-1 - Deduction for capital gains.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    .... (a) In computing gross income, adjusted gross income, taxable income, capital gain net income (net capital gain for taxable years beginning before January 1, 1977) and net capital loss, 100 percent of any... without regard to subchapter P (section 1201 and following), chapter 1 of the Code) upon the sale...

  7. 26 CFR 1.1202-1 - Deduction for capital gains.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    .... (a) In computing gross income, adjusted gross income, taxable income, capital gain net income (net capital gain for taxable years beginning before January 1, 1977) and net capital loss, 100 percent of any... without regard to subchapter P (section 1201 and following), chapter 1 of the Code) upon the sale...

  8. Intellect, Perceptual Characteristics, and Weight Gain in Anorexia Nervosa.

    ERIC Educational Resources Information Center

    Small, Arnold; And Others

    1983-01-01

    Studied weight-gain 127 primary anorexics by examining the Wechsler Adult Intelligence Scale and the Rorschach for indices that may predict improvement. Results showed that cognitive-focusing skills, measured by the Wechsler, account for roughly half of the variance and were good predictors of weight gain. (WAS)

  9. Optimal gains for a single polar orbiting satellite

    NASA Technical Reports Server (NTRS)

    Banfield, Don; Ingersoll, A. P.; Keppenne, C. L.

    1993-01-01

    Gains are the spatial weighting of an observation in its neighborhood versus the local values of a model prediction. They are the key to data assimilation, as they are the direct measure of how the data are used to guide the model. As derived in the broad context of data assimilation by Kalman and in the context of meteorology, for example, by Rutherford, the optimal gains are functions of the prediction error covariances between the observation and analysis points. Kalman introduced a very powerful technique that allows one to calculate these optimal gains at the time of each observation. Unfortunately, this technique is both computationally expensive and often numerically unstable for dynamical systems of the magnitude of meteorological models, and thus is unsuited for use in PMIRR data assimilation. However, the optimal gains as calculated by a Kalman filter do reach a steady state for regular observing patterns like that of a satellite. In this steady state, the gains are constants in time, and thus could conceivably be computed off-line. These steady-state Kalman gains (i.e., Wiener gains) would yield optimal performance without the computational burden of true Kalman filtering. We proposed to use this type of constant-in-time Wiener gain for the assimilation of data from PMIRR and Mars Observer.

  10. 34 CFR 462.43 - How is educational gain measured?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 34 Education 3 2014-07-01 2014-07-01 false How is educational gain measured? 462.43 Section 462.43 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF VOCATIONAL AND ADULT EDUCATION, DEPARTMENT OF EDUCATION MEASURING EDUCATIONAL GAIN IN THE NATIONAL REPORTING SYSTEM...

  11. 34 CFR 462.43 - How is educational gain measured?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 34 Education 3 2013-07-01 2013-07-01 false How is educational gain measured? 462.43 Section 462.43 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF VOCATIONAL AND ADULT EDUCATION, DEPARTMENT OF EDUCATION MEASURING EDUCATIONAL GAIN IN THE NATIONAL REPORTING SYSTEM...

  12. Sustaining Student Gains from Online On-Demand Professional Development

    ERIC Educational Resources Information Center

    Shaha, Steven H.; Glassett, Kelly; Copas, Aimee

    2015-01-01

    A multi-State, quasi-experimental study was conducted as a longitudinal, two-year follow-up of participation in an online, on-demand professional development (PD) program. The purpose was to ascertain whether student gains were sustained in a second year of PD participation. Data verified gains in Year 1 versus Pre-PD baseline, with continued…

  13. Managing Urban School System Resources: New Procedures, Addition Actors.

    ERIC Educational Resources Information Center

    Hentschke, Guilbert C.

    In recent years urban school systems have had to face unusually severe economic constraints. In the process of adjusting to these constraints, urban systems will likely seek new ways to reallocate existing resources and will undertake more cooperative ventures with other organizational entities to gain access to additional resources. Four…

  14. Phenolic plant metabolites as bioactive food and feed additives

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Functional additives in food and animal feed formulations are gaining acceptance as consumers and producers recognize the health benefits associated with certain natural plant products. Phenolic compounds in particular have emerged as a class of compounds with antioxidant, antibacterial, and antifun...

  15. Impact of GEM foil hole geometry on GEM detector gain

    NASA Astrophysics Data System (ADS)

    Karadzhinova, A.; Nolvi, A.; Veenhof, R.; Tuominen, E.; Hæggström, E.; Kassamakov, I.

    2015-12-01

    Detailed 3D imaging of Gas Electron Multiplier (GEM) foil hole geometry was realized. Scanning White Light Interferometry was used to examine six topological parameters of GEM foil holes from both sides of the foil. To study the effect of the hole geometry on detector gain, the ANSYS and Garfield ++ software were employed to simulate the GEM detector gain on the basis of SWLI data. In particular, the effective gain in a GEM foil with equally shaped holes was studied. The real GEM foil holes exhibited a 4% lower effective gain and 6% more electrons produced near the exit electrode of the GEM foil than the design anticipated. Our results indicate that the GEM foil hole geometry affects the gain performance of GEM detectors.

  16. Threshold improvement and acoustic gain with hearing aids.

    PubMed

    Walden, B E; Kasten, R N

    1976-01-01

    Aided speech reception thresholds were obtained from 20 hearing-impaired listeners with three hearing aids adjusted to confort settings, and with the aids adjusted to deliver 40 dB of acoustic gain. The aided speech reception threshold under each condition was substracted from the unaided speech reception threshold to yield a measure of threshold improvement. Threshold improvement and acoustic gain comparisons revealed that, at comfort setting, these two measures were quite similar. However, at the 40-dB gain setting, acoustic gain exceeded threshold improvement by an average of 5.6 dB. For the high-gain condition, it appeared that the threshold improvement obtained by subjects with relatively good unaided sensitivity was limited by the ambient noise in the test chamber.

  17. Threshold improvement and acoustic gain with hearing aids.

    PubMed

    Walden, B E; Kasten, R N

    1976-01-01

    Aided speech reception thresholds were obtained from 20 hearing-impaired listeners with three hearing aids adjusted to confort settings, and with the aids adjusted to deliver 40 dB of acoustic gain. The aided speech reception threshold under each condition was substracted from the unaided speech reception threshold to yield a measure of threshold improvement. Threshold improvement and acoustic gain comparisons revealed that, at comfort setting, these two measures were quite similar. However, at the 40-dB gain setting, acoustic gain exceeded threshold improvement by an average of 5.6 dB. For the high-gain condition, it appeared that the threshold improvement obtained by subjects with relatively good unaided sensitivity was limited by the ambient noise in the test chamber. PMID:938347

  18. Adaptive gain and filtering circuit for a sound reproduction system

    NASA Technical Reports Server (NTRS)

    Engebretson, A. Maynard (Inventor); O'Connell, Michael P. (Inventor)

    1998-01-01

    Adaptive compressive gain and level dependent spectral shaping circuitry for a hearing aid include a microphone to produce an input signal and a plurality of channels connected to a common circuit output. Each channel has a preset frequency response. Each channel includes a filter with a preset frequency response to receive the input signal and to produce a filtered signal, a channel amplifier to amplify the filtered signal to produce a channel output signal, a threshold register to establish a channel threshold level, and a gain circuit. The gain circuit increases the gain of the channel amplifier when the channel output signal falls below the channel threshold level and decreases the gain of the channel amplifier when the channel output signal rises above the channel threshold level. A transducer produces sound in response to the signal passed by the common circuit output.

  19. Comparison of Gain-Like Properties of Eye Position Signals in Inferior Colliculus Versus Auditory Cortex of Primates

    PubMed Central

    Maier, Joost X.; Groh, Jennifer M.

    2010-01-01

    We evaluated to what extent the influence of eye position in the auditory pathway of primates can be described as a gain field. We compared single unit activity in the inferior colliculus (IC), core auditory cortex (A1) and the caudomedial belt (CM) region of auditory cortex (AC) in primates, and found stronger evidence for gain field-like interactions in the IC than in AC. In the IC, eye position signals showed both multiplicative and additive interactions with auditory responses, whereas in AC the effects were not as well predicted by a gain field model. PMID:20838470

  20. Relationship Between Optimal Gain and Coherence Zone in Flight Simulation

    NASA Technical Reports Server (NTRS)

    Gracio, Bruno Jorge Correia; Pais, Ana Rita Valente; vanPaassen, M. M.; Mulder, Max; Kely, Lon C.; Houck, Jacob A.

    2011-01-01

    In motion simulation the inertial information generated by the motion platform is most of the times different from the visual information in the simulator displays. This occurs due to the physical limits of the motion platform. However, for small motions that are within the physical limits of the motion platform, one-to-one motion, i.e. visual information equal to inertial information, is possible. It has been shown in previous studies that one-to-one motion is often judged as too strong, causing researchers to lower the inertial amplitude. When trying to measure the optimal inertial gain for a visual amplitude, we found a zone of optimal gains instead of a single value. Such result seems related with the coherence zones that have been measured in flight simulation studies. However, the optimal gain results were never directly related with the coherence zones. In this study we investigated whether the optimal gain measurements are the same as the coherence zone measurements. We also try to infer if the results obtained from the two measurements can be used to differentiate between simulators with different configurations. An experiment was conducted at the NASA Langley Research Center which used both the Cockpit Motion Facility and the Visual Motion Simulator. The results show that the inertial gains obtained with the optimal gain are different than the ones obtained with the coherence zone measurements. The optimal gain is within the coherence zone.The point of mean optimal gain was lower and further away from the one-to-one line than the point of mean coherence. The zone width obtained for the coherence zone measurements was dependent on the visual amplitude and frequency. For the optimal gain, the zone width remained constant when the visual amplitude and frequency were varied. We found no effect of the simulator configuration in both the coherence zone and optimal gain measurements.

  1. Saccharin and aspartame, compared with sucrose, induce greater weight gain in adult Wistar rats, at similar total caloric intake levels.

    PubMed

    Feijó, Fernanda de Matos; Ballard, Cíntia Reis; Foletto, Kelly Carraro; Batista, Bruna Aparecida Melo; Neves, Alice Magagnin; Ribeiro, Maria Flávia Marques; Bertoluci, Marcello Casaccia

    2013-01-01

    It has been suggested that the use of nonnutritive sweeteners (NNSs) can lead to weight gain, but evidence regarding their real effect in body weight and satiety is still inconclusive. Using a rat model, the present study compares the effect of saccharin and aspartame to sucrose in body weight gain and in caloric intake. Twenty-nine male Wistar rats received plain yogurt sweetened with 20% sucrose, 0.3% sodium saccharin or 0.4% aspartame, in addition to chow and water ad libitum, while physical activity was restrained. Measurements of cumulative body weight gain, total caloric intake, caloric intake of chow and caloric intake of sweetened yogurt were performed weekly for 12 weeks. Results showed that addition of either saccharin or aspartame to yogurt resulted in increased weight gain compared to addition of sucrose, however total caloric intake was similar among groups. In conclusion, greater weight gain was promoted by the use of saccharin or aspartame, compared with sucrose, and this weight gain was unrelated to caloric intake. We speculate that a decrease in energy expenditure or increase in fluid retention might be involved.

  2. Gain-switched pulses from InGaAs ridge-quantum-well lasers limited by intrinsic dynamical gain suppression.

    PubMed

    Chen, Shaoqiang; Yoshita, Masahiro; Ito, Takashi; Mochizuki, Toshimitsu; Akiyama, Hidefumi; Yokoyama, Hiroyuki

    2013-03-25

    Gain-switched pulses of InGaAs double-quantum-well lasers fabricated from identical epitaxial laser wafers were measured under both current injection and optical pumping conditions. The shortest output pulse widths were nearly identical (about 40 ps) both for current injection and optical pumping; this result attributed the dominant pulse-width limitation factor to the intrinsic gain properties of the lasers. We quantitatively compared the experimental results with theoretical calculations based on rate equations incorporating gain nonlinearities. Close consistency between the experimental data and the calculations was obtained only when we assumed a dynamically suppressed gain value deviated from the steady-state gain value supported by standard microscopic theories.

  3. Gain fixed-pattern-noise correction via optical flow

    NASA Astrophysics Data System (ADS)

    Lim, SukHwan; El Gamal, Abbas

    2002-04-01

    Fixed pattern noise (FPN) or nonuniformity caused by device and interconnect parameter variations across an image sensor is a major source of image quality degradation especially in CMOS image sensors. In a CMOS image sensor, pixels are read out through different chains of amplifiers each with different gain and offset. Whereas offset variations can be significantly reduced using correlated double sampling (CDS), no widely used method exists for reducing gain FPN. In this paper, we propose to use a video sequence and its optical flow to estimate gain FPN for each pixel. This scheme can be used in a digital video or still camera by taking any video sequence with motion prior to capture and using it to estimate gain FPN. Our method assumes that brightness along the motion trajectory is constant over time. The pixels are grouped in blocks and each block's pixel gains are estimated by iteratively minimizing the sum of the squared brightness variations along the motion trajectories. We tested this method on synthetically generated sequences with gain FPN and obtained results that demonstrate significant reduction in gain FPN with modest computations.

  4. Characterization of transient gain x-ray lasers

    SciTech Connect

    Dunn, J; Osterheld, A; Shlyaptsev, V

    1999-02-07

    We have performed numerical simulations of the transient collisional excitation Ni-like Pd 4d {r_arrow} 4p J = 0 {r_arrow} 1 147 {angstrom} laser transition recently observed at Lawrence Livermore National Laboratory (LLNL). The high gain {approximately}35 cm results from the experiment are compared with detailed modeling simulations from the 1-D RADEX code in order to better understand the main physics issues affecting the measured gain and x-ray laser propagation along the plasma column. Simulations indicate that the transient gain lifetime associated with the short pulse pumping and refraction of the x-ray laser beam out of the gain region are the main detrimental effects. Gain lifetimes of {approximately}7 ps(1/e decay) are inferred from the smoothly changing gain experimental observations and are in good agreement with the simulations. Furthermore, the modeling results indicate the presence of a longer-lived but lower gain later in time associated with the transition from transient to quasi-steady state excitation.

  5. Gain Scheduling for the Orion Launch Abort Vehicle Controller

    NASA Technical Reports Server (NTRS)

    McNamara, Sara J.; Restrepo, Carolina I.; Madsen, Jennifer M.; Medina, Edgar A.; Proud, Ryan W.; Whitley, Ryan J.

    2011-01-01

    One of NASAs challenges for the Orion vehicle is the control system design for the Launch Abort Vehicle (LAV), which is required to abort safely at any time during the atmospheric ascent portion of ight. The focus of this paper is the gain design and scheduling process for a controller that covers the wide range of vehicle configurations and flight conditions experienced during the full envelope of potential abort trajectories from the pad to exo-atmospheric flight. Several factors are taken into account in the automation process for tuning the gains including the abort effectors, the environmental changes and the autopilot modes. Gain scheduling is accomplished using a linear quadratic regulator (LQR) approach for the decoupled, simplified linear model throughout the operational envelope in time, altitude and Mach number. The derived gains are then implemented into the full linear model for controller requirement validation. Finally, the gains are tested and evaluated in a non-linear simulation using the vehicles ight software to ensure performance requirements are met. An overview of the LAV controller design and a description of the linear plant models are presented. Examples of the most significant challenges with the automation of the gain tuning process are then discussed. In conclusion, the paper will consider the lessons learned through out the process, especially in regards to automation, and examine the usefulness of the gain scheduling tool and process developed as applicable to non-Orion vehicles.

  6. Gain properties of dye-doped polymer thin films

    NASA Astrophysics Data System (ADS)

    Gozhyk, I.; Boudreau, M.; Haghighi, H. Rabbani; Djellali, N.; Forget, S.; Chénais, S.; Ulysse, C.; Brosseau, A.; Pansu, R.; Audibert, J.-F.; Gauvin, S.; Zyss, J.; Lebental, M.

    2015-12-01

    Hybrid pumping appears as a promising compromise in order to reach the much coveted goal of an electrically pumped organic laser. In such configuration the organic material is optically pumped by an electrically pumped inorganic device on a chip. This engineering solution requires therefore an optimization of the organic gain medium under optical pumping. Here, we report a detailed study of the gain features of dye-doped polymer thin films. In particular we introduce the gain efficiency K , in order to facilitate comparison between different materials and experimental conditions. The gain efficiency was measured with a variety of experimental methods (pump-probe amplification, variable stripe length method, laser thresholds) in order to study several factors which modify the actual gain of a layer, namely the confinement factor, the pump polarization, the molecular anisotropy, and the re-absorption. For instance, for a 600-nm-thick 5-wt % DCM doped poly(methyl methacrylate) (PMMA) layer, the different experimental approaches give a consistent value of K ≃ 80 -cm MW-1 . On the contrary, the usual model predicting the gain from the characteristics of the material leads to an overestimation by two orders of magnitude, which raises a serious problem in the design of actual devices. In this context, we demonstrate the feasibility to infer the gain efficiency from the laser threshold of well-calibrated devices. Temporal measurements at the picosecond scale were carried out to support the analysis.

  7. LPV Controller Interpolation for Improved Gain-Scheduling Control Performance

    NASA Technical Reports Server (NTRS)

    Wu, Fen; Kim, SungWan

    2002-01-01

    In this paper, a new gain-scheduling control design approach is proposed by combining LPV (linear parameter-varying) control theory with interpolation techniques. The improvement of gain-scheduled controllers can be achieved from local synthesis of Lyapunov functions and continuous construction of a global Lyapunov function by interpolation. It has been shown that this combined LPV control design scheme is capable of improving closed-loop performance derived from local performance improvement. The gain of the LPV controller will also change continuously across parameter space. The advantages of the newly proposed LPV control is demonstrated through a detailed AMB controller design example.

  8. High gain, wide field of view concentrator for optical communications.

    PubMed

    Collins, Steve; O'Brien, Dominic C; Watt, Andrew

    2014-04-01

    The field of view and gain of optical concentrators used within free space optical communications systems are constrained by conservation of etendue. In this Letter, consideration of the processes in a fluorescent concentrator leads to a simple design strategy for these concentrators for this application. Significantly, because fluorescent concentrators do not conserve etendue, this can lead to concentrators with wider fields of view and higher gains. A model of a fluorescent concentrator containing a quantum dot material suggests that it could have a gain 50 times higher than an etendue conserving concentrator with the same field of view.

  9. Gain enhancement of microstrip antennas with overlaying parasitic directors

    NASA Technical Reports Server (NTRS)

    Lee, R. Q.; Lee, K. F.

    1988-01-01

    An experimental study of gain enhancement in microstrip antennas using identical parasitic patch directors is reported. The results indicate that, with two overlying parasitic directors, the gain of a rectangular microstrip antenna is enhanced from 4.7 dB to 10.6 dB, while the 3 dB beamwidth is reduced from 103 deg to 30 deg for the E-plane and from 70 deg to 35 deg for the H-plane. The three-layer electromagnetically coupled patch antenna exhibits similar antenna characteristics to those of the Yagi array, with over 120 dB gain and with about 1 percent bandwidth.

  10. Relationship of acoustic gain to aided threshold improvement in children.

    PubMed

    Jirsa, R E; Norris, T W

    1978-08-01

    Aided threshold improvement obtained by 12 hearing-impaired children was compared to the acoustic gain of their hearing aids using both the traditional 2-cc coupler and a variable volume coupler designed to approximate real ear volume in children. Results indicated that acoustic gain determined in the 2-cc coupler underestimated aided threshold improvement by approximately 8.7 dB. Use of the variable volume coupler to determine acoustic gain, however, adequately predicted aided improvement at comfort setting. Use of the variable volume coupler in hearing-aid fittings for children is discussed with special emphasis on preventing over-amplification.

  11. Antipsychotic induced weight gain in schizophrenia:mechanisms and management.

    PubMed

    Rege, Sanil

    2008-05-01

    The aim of the present paper was to describe the mechanisms and management of antipsychotic-induced weight gain in schizophrenia patients. A comprehensive literature review of all available articles on the mechanisms and management of antipsychotic-induced weight gain was done by searching databases PsychINFO and PubMed. A summary of the available guidelines for monitoring of antipsychotic-induced weight gain and metabolic syndrome is also provided. There has been a substantial increase in the number of studies investigating the mechanisms and management of antipsychotic-induced weight gain after 2002. These include advances in the understanding of pharmacogenomics of weight gain and several randomized controlled trials (RCTs) evaluating pharmacological and psychological treatments to promote weight loss. The most effective strategy for prevention of weight gain is the choice of antipsychotic medication with low weight gain potential. In individuals with established weight gain and metabolic issues, switching to an antipsychotic agent with lower weight gain potential and/or lifestyle modifications with physical activity are most effective in promoting weight loss. Pharmacological agents such as orlistat and sibutramine are effective in general obesity but have not been sufficiently evaluated in antipsychotic-induced weight gain. The case to prescribe routine pharmacological treatment to promote weight loss is weak. Long-term, pragmatic studies are required to inform clinical practice. Weight gain in schizophrenia is associated with significant physical and psychological morbidity. Achieving an optimal trade-off between effectiveness and side-effects of antipsychotic agents, although difficult, is achievable. This should be based on three main principles: (i) a shared decision-making model between the patient, clinician and carer(s) when choosing an antipsychotic; (ii) a commitment to baseline and follow-up monitoring with explicit identification of the responsible

  12. Decoupling approximation design using the peak to peak gain

    NASA Astrophysics Data System (ADS)

    Sultan, Cornel

    2013-04-01

    Linear system design for accurate decoupling approximation is examined using the peak to peak gain of the error system. The design problem consists in finding values of system parameters to ensure that this gain is small. For this purpose a computationally inexpensive upper bound on the peak to peak gain, namely the star norm, is minimized using a stochastic method. Examples of the methodology's application to tensegrity structures design are presented. Connections between the accuracy of the approximation, the damping matrix, and the natural frequencies of the system are examined, as well as decoupling in the context of open and closed loop control.

  13. Inhomogeneous Gain Saturation in EDF: Experiment and Modeling

    NASA Astrophysics Data System (ADS)

    Peretti, Romain; Jacquier, Bernard; Boivin, David; Burov, Ekaterina; Jurdyc, Anne-Marie

    2011-05-01

    Erbium-Doped Fiber Amplifiers can present holes in spectral gain in Wavelength Division Multiplexing operation. The origin of this inhomogeneous saturation behavior is still a subject of controversy. In this paper we present both an experimental methods and a gain's model. Our experimental method allow us to measure the first homogeneous linewidth of the 1.5 $\\mu$m erbium emission with gain spectral hole burning consistently with the other measurement in the literature and the model explains the differences observed in literature between GSHB and other measurement methods.

  14. Symmetry breaking and multipeaked solitons in inhomogeneous gain landscapes

    SciTech Connect

    Kartashov, Yaroslav V.; Vysloukh, Victor A.; Konotop, Vladimir V.

    2011-04-15

    We address one-dimensional soliton formation in a cubic nonlinear medium with two-photon absorption and transversally inhomogeneous gain landscape consisting of a single or several amplifying channels. Existence of the solitons requires certain threshold gain while the properties of solitons strongly depend on whether the number of the amplifying channels is odd or even. In the former case, an increase of the gain leads to symmetry breaking, which occurs through the pitchfork bifurcation, and to emergence of a single or several coexisting stable asymmetric modes. In the case of an even number of amplifying channels, we have found only asymmetric stable states.

  15. Ribbon Fiber with Multiple Antiguided Phase-Locked Gain Cores

    SciTech Connect

    Beach, R J; Feit, M D; Mitchell, S C; Cutter, K P; Dawson, J W; Payne, S A

    2002-11-20

    We report on the first experimental demonstration of a scalable fiber laser approach based on phase-locking multiple gain cores in an antiguided structure. A novel fabrication technology is used with soft glass components to construct the multiple core fiber used in our experiments. The waveguide region is rectangular in shape and comprised of a periodic sequence of gain and no-gain segments having nearly uniform refractive index. The rectangular waveguide is itself embedded in a lower refractive index cladding region. Experimental results confirm that our five-core Nd doped glass prototype structure runs predominantly in two spatial antiguided modes as predicted by our modeling.

  16. High gain single GaAs nanowire photodetector

    NASA Astrophysics Data System (ADS)

    Wang, Hao

    2013-08-01

    An undoped single GaAs nanowire (NW) photodetector based on a metal-semiconductor-metal Schottky diode structure is fabricated by a focused ion beam method. The photoconductive gain of the device reaches 20 000 at low laser excitation. Bias-dependence of gain proves that the surface contributes more to the gain at higher bias because of an increased surface charge region. The spectral response demonstrates not only the band-edge absorption profile of the single GaAs NW, but also the existence of leaky-mode resonance.

  17. Gain saturation in semiconductor lasers - Theory and experiment

    NASA Technical Reports Server (NTRS)

    Kasemset, D.; Fonstad, C. G., Jr.

    1982-01-01

    The semiconductor stimulated gain saturation model of Zee has been extended using reasonable approximations to obtain an analytical solution for the gain saturation process in PbSnTe and to determine the limit to single mode power directly from the gain expression, the intraband relaxation time, and device and material parameters. The theoretical results are compared with experimental observations for single transverse mode cavity narrow stripe buried heterostructure PbSnTe lasers. Those results are interpreted in terms of an intraband relaxation time on the order of 2 x 10 to the -12th s in the temperature range 20-80 K.

  18. Measuring gain-sharing dividends in acute care hospitals.

    PubMed

    Barbusca, A; Cleek, M

    1994-01-01

    Hospitals have responded to industry consolidation by increasing productivity with nonmanagement, group-incentive compensation, known as gain sharing. A nationwide study conducted to obtain quantitative performance data for gain-sharing programs revealed that they are most successful during the initial stages of the program. Many variables affect the size of employee bonuses and the duration of employee support. Employers must identify how to appropriately install their gain-sharing program so that employee motivation, participation, and trust in management are maximized. PMID:8206759

  19. Divergence and Convergence of Risky Decision Making Across Prospective Gains and Losses: Preferences and Strategies

    PubMed Central

    Kurnianingsih, Yoanna A.; Mullette-Gillman, O'Dhaniel A.

    2015-01-01

    People choose differently when facing potential gains than when facing potential losses. Clear gross differences in decision making between gains and losses have been empirically demonstrated in numerous studies (e.g., framing effect, risk preference, loss aversion). However, theories maintain that there are strong underlying connections (e.g., reflection effect). We investigated the relationship between gains and losses decision making, examining risk preferences, and choice strategies (the reliance on option information) using a monetary gamble task with interleaved trials. For risk preferences, participants were on average risk averse in the gains domain and risk neutral/seeking in the losses domain. We specifically tested for a theoretically hypothesized correlation between individual risk preferences across the gains and losses domains (the reflection effect), but found no significant relationship in the predicted direction. Interestingly, despite the lack of reflected risk preferences, cross-domain risk preferences were still informative of individual choice behavior. For choice strategies, in both domains participants relied more heavily on the maximizing strategy than the satisficing strategy, with increased reliance on the maximizing strategy in the losses domain. Additionally, while there is no mathematical reliance between the risk preference and strategy metrics, within both domains there were significant relationships between risk preferences and strategies—the more participants relied upon the maximizing strategy the more risk neutral they were (equating value and utility maximization). These results demonstrate the complexity of gains and losses decision making, indicating the apparent contradiction that their underlying cognitive/neural processes are both dissociable and overlapping. PMID:26733779

  20. Inadequate gestational weight gain and adverse pregnancy outcomes among normal weight women in China

    PubMed Central

    Wen, Tingyuan; Lv, Yanwei

    2015-01-01

    Objective: The objective of the paper is to find the association between inadequate gestational weight gain and pregnancy outcomes in normal weight women in China. Method: A retrospective study was conducted among 13,776 normal weight pregnant women who received antenatal care and delivered singleton infants at the participating hospital during August, 2009 to July, 2013. Adverse pregnancy outcomes like low birth weight (LBW), preterm birth, birth asphyxia, neonatal intensive care unit (NICU) admission and length of hospital stay were compared and analyzed between two groups with inadequate and adequate gestational weight gain. Results: According to the IOM recommendations, inadequate gestational weight gain was found to be 14.7% in this study. Women with inadequate gestational weight gain (GWG) were found to be at a higher risk for LBW (aOR = 2.13, 95% CI: 1.75, 2.86) and preterm birth (aOR = 1.44, 95% CI: 1.21, 1.67) than those in the adequate gestational weight gain group, after adjusting for monthly family income, maternal education, occupation, and whether they received any advice regarding benefits of gestational weight gain and residential area. However, inadequate GWG was not associated with longer hospital stay (aOR = 1.13, 95% CI: 0.91-1.43) in adjusted model. In addition, the rate of birth asphyxia and NICU admission were similar in both groups (P > 0.05). Conclusions: Normal weight pregnant women with GWG below the recommended AIOM 2009 guidelines were found to be at an increased risk of low birth weight and preterm birth. PMID:25932249

  1. Association of LEPR and ANKK1 Gene Polymorphisms with Weight Gain in Epilepsy Patients Receiving Valproic Acid

    PubMed Central

    Li, Hongliang; Wang, Xueding; Zhou, Yafang; Ni, Guanzhong; Su, Qibiao; Chen, Ziyi; Chen, Zhuojia; Li, Jiali; Chen, Xinmeng; Hou, Xiangyu; Xie, Wen; Xin, Shuang; Zhou, Liemin

    2015-01-01

    Background: Weight gain is the most frequent adverse effect of valproic acid (VPA) treatment, resulting in poor compliance and many endocrine disturbances. Similarities in the weight change of monozygotic twins receiving VPA strongly suggests that genetic factors are involved in this effect. However, few studies have been conducted to identify the relevant genetic polymorphisms. Additionally, the causal relationship between the VPA concentration and weight gain has been controversial. Thus, we investigated the effects of single nucleotide polymorphisms (SNPs) in several appetite stimulation and energy homeostasis genes and the steady state plasma concentrations (Css) of VPA on the occurrence of weight gain in patients. Methods: A total of 212 epilepsy patients receiving VPA were enrolled. Nineteen SNPs in 11 genes were detected using the Sequenom MassArray iPlex platform, and VPA Css was determined by high-performance liquid chromatography (HPLC). Results: After 6 months of treatment, 20.28% of patients were found to gain a significant amount of weight (weight gained ≥7%). Three SNPs in the leptin receptor (LEPR), ankyrin repeat kinase domain containing 1 (ANKK1), and α catalytic subunit of adenosine monophosphate-activated protein kinase (AMPK) showed significant associations with VPA-induced weight gain (p < 0.001, p = 0.017 and p = 0.020, respectively). After Bonferroni correction for multiple tests, the genotypic association of LEPR rs1137101, the allelic association of LEPR rs1137101, and ANKK1 rs1800497 with weight gain remained significant. However, the VPA Css in patents who gained weight were not significantly different from those who did not gain weight (p = 0.121). Conclusions: LEPR and ANKK1 genetic polymorphisms may have value in predicting VPA-induced weight gain. PMID:25740917

  2. The Effect of Capital Gains Taxation on Home Sales: Evidence from the Taxpayer Relief Act of 1997

    PubMed Central

    Shan, Hui

    2010-01-01

    The Taxpayer Relief Act of 1997 (TRA97) significantly changed the tax treatment of housing capital gains in the United States. Before 1997, homeowners were subject to capital gains taxation when they sold their houses unless they purchased replacement homes of equal or greater value. Since 1997, homeowners can exclude capital gains of $500,000 (or $250,000 for single filers) when they sell their houses. Such dramatic changes provide a good opportunity to study the lock-in effect of capital gains taxation on home sales. Using 1982–2008 transaction data on single-family houses in 16 affluent towns within the Boston metropolitan area, I find that TRA97 reversed the lock-in effect of capital gains taxes on houses with low and moderate capital gains. Specifically, the semiannual sales rate of houses with positive gains up to $500,000 increased by 0.40–0.62 percentage points after TRA97, representing a 19–24 percent increase from the pre-TRA97 baseline sales rate. In contrast, I do not find TRA97 to have a significant effect on houses with gains above $500,000. Moreover, the short-term effect of TRA97 is much larger than the long-term effect, suggesting that many previously locked-in homeowners took advantage of the exclusions immediately after TRA97. In addition, I exploit the 2001 and 2003 legislative changes in the capital gains tax rate to estimate the tax elasticity of home sales during the post-TRA97 period. The estimation results suggest that a $10,000 increase in capital gains taxes reduces the semiannual home sales rate by about 0.1–0.2 percentage points, or 6–13 percent from the post-TRA97 average sales rate. PMID:21170145

  3. Negative Differential Resistance (NDR) frequency conversion with gain

    NASA Technical Reports Server (NTRS)

    Hwu, R. J.; Alm, R. W.; Lee, S. C.

    1992-01-01

    The dependence of the I-V characteristic of the negative differential resistance (NDR) devices on the power level and frequency of the rf input signal has been theoretically analyzed with a modified large- and small-signal nonlinear circuit analysis program. The NDR devices we used in this work include both the tunnel diode (without the antisymmetry in the I-V characteristic) and resonant-tunneling devices (with the antisymmetry in the I-V characteristic). Absolute negative conductance can be found from a zero-biased resonant tunneling device when the applied pump power is within a small range. This study verifies the work of Sollner et al. Variable negative conductances at the fundamental and harmonic frequencies can also be obtained from both the unbiased and biased tunnel diodes. The magnitude of the negative conductances can be adjusted by varying the pump amplitude -- a very useful circuit property. However, the voltage range over which the negative conductance occurs moves towards the more positive side of the voltage axis with increasing frequency. Furthermore, the range of the pumping amplitude to obtain negative conductance varies with the parasitics (resistance and capacitance) of the device. The theoretical observation of the dependence of the I-V characteristic of the NDR devices on the power and frequency of the applied pump signal is supported by the experimental results. In addition, novel functions of a NDR device such as self-oscillating frequency multiplier and mixer with gain have been experimentally demonstrated. The unbiased oscillator have also been successfully realized with a NDR device with an antisymmetrical I-V characteristic. Finally, the applications of these device functions will be discussed.

  4. Nucleus accumbens response to gains in reputation for the self relative to gains for others predicts social media use

    PubMed Central

    Meshi, Dar; Morawetz, Carmen; Heekeren, Hauke R.

    2013-01-01

    Our reputation is important to us; we've experienced natural selection to care about our reputation. Recently, the neural processing of gains in reputation (positive social feedback concerning one's character) has been shown to occur in the human ventral striatum. It is still unclear, however, how individual differences in the processing of gains in reputation may lead to individual differences in real-world behavior. For example, in the real-world, one way that people currently maintain their reputation is by using social media websites, like Facebook. Furthermore, Facebook use consists of a social comparison component, where users observe others' behavior and can compare it to their own. Therefore, we hypothesized a relationship between the way the brain processes specifically self-relevant gains in reputation and one's degree of Facebook use. We recorded functional neuroimaging data while participants received gains in reputation, observed the gains in reputation of another person, or received monetary reward. We demonstrate that across participants, when responding to gains in reputation for the self, relative to observing gains for others, reward-related activity in the left nucleus accumbens predicts Facebook use. However, nucleus accumbens activity in response to monetary reward did not predict Facebook use. Finally, a control step-wise regression analysis showed that Facebook use primarily explains our results in the nucleus accumbens. Overall, our results demonstrate how individual sensitivity of the nucleus accumbens to the receipt of self-relevant social information leads to differences in real-world behavior. PMID:24009567

  5. Nucleus accumbens response to gains in reputation for the self relative to gains for others predicts social media use.

    PubMed

    Meshi, Dar; Morawetz, Carmen; Heekeren, Hauke R

    2013-01-01

    Our reputation is important to us; we've experienced natural selection to care about our reputation. Recently, the neural processing of gains in reputation (positive social feedback concerning one's character) has been shown to occur in the human ventral striatum. It is still unclear, however, how individual differences in the processing of gains in reputation may lead to individual differences in real-world behavior. For example, in the real-world, one way that people currently maintain their reputation is by using social media websites, like Facebook. Furthermore, Facebook use consists of a social comparison component, where users observe others' behavior and can compare it to their own. Therefore, we hypothesized a relationship between the way the brain processes specifically self-relevant gains in reputation and one's degree of Facebook use. We recorded functional neuroimaging data while participants received gains in reputation, observed the gains in reputation of another person, or received monetary reward. We demonstrate that across participants, when responding to gains in reputation for the self, relative to observing gains for others, reward-related activity in the left nucleus accumbens predicts Facebook use. However, nucleus accumbens activity in response to monetary reward did not predict Facebook use. Finally, a control step-wise regression analysis showed that Facebook use primarily explains our results in the nucleus accumbens. Overall, our results demonstrate how individual sensitivity of the nucleus accumbens to the receipt of self-relevant social information leads to differences in real-world behavior.

  6. Occupational health experience with organic additives.

    PubMed

    Thiess, A M; Wellenreuther, G

    1984-12-01

    For many decades, interest in occupational medicine has been focused on the wide variety of organic additives, which includes a large number of substances, for example, dyestuffs, pigments, and auxiliaries for the textile, leather, and paper industries. The reason is that, if the recommended precautions are not observed, there is a risk of exposure to most of these substances during both production and use. Moreover, over the years, some additives have caused concern and aroused suspicion regarding adverse effects on health. In order to deal with health problems in this field, it is important to be aware of how, what, and where occupational diseases or accidents arise. Much knowledge has been gained about these, and it would be an impossible task to give a systematic survey of the data that have accumulated, especially since it is necessary to take account of the problem of exposure to more than one substance. Thus an attempt is made to report on occupational health experience in general, and to demonstrate how an industrial hygienist may approach the many and various problems. Some epidemiological studies on organic additives (auramine, anthraquinone dyestuffs, organic dyes, etc.) are discussed.

  7. Review of health and productivity gains from better IEQ

    SciTech Connect

    Fisk, William J.

    2000-08-01

    The available scientific data suggest that existing technologies and procedures can improve indoor environmental quality (IEQ) in a manner that significantly increases productivity and health. While there is considerable uncertainty in the estimates of the magnitudes of productivity gains that may be obtained, the projected gains are very large. For the U.S., the estimated potential annual savings and productivity gains are $6 to $14 billion from reduced respiratory disease, $2 to $4 billion from reduced allergies and asthma, $10 to $30 billion from reduced sick building syndrome symptoms, and $20 to $160 billion from direct improvements in worker performance that are unrelated to health. Productivity gains that are quantified and demonstrated could serve as a strong stimulus for energy efficiency measures that simultaneously improve the indoor environment.

  8. Healthy Diet as Teen, Less Weight Gain as Adult

    MedlinePlus

    ... medlineplus.gov/news/fullstory_161134.html Healthy Diet as Teen, Less Weight Gain as Adult Study suggests food choices made at 15 ... researchers report. Encouraging more young people to eat a variety of fruits and vegetables as well as ...

  9. Gain and efficiency of a stimulated Cherenkov optical Klystron

    SciTech Connect

    Wang, D.Y.; Fauchet, A.; Pantell, R.H.; Piestrup, M.A.

    1983-03-01

    A scheme for building an optical klystron oscillator based on the stimulated Cherenkov interaction between light and relativistic electrons is presented. The gain and efficiency of such a device as a function of wavelength is discussed.

  10. Context-specific adaptation of saccade gain in parabolic flight

    NASA Technical Reports Server (NTRS)

    Shelhamer, Mark; Clendaniel, Richard A.; Roberts, Dale C.

    2002-01-01

    Previous studies established that vestibular reflexes can have two adapted states (e.g., gains) simultaneously, and that a context cue (e.g., vertical eye position) can switch between the two states. Our earlier work demonstrated this phenomenon of context-specific adaptation for saccadic eye movements: we asked for gain decrease in one context state and gain increase in another context state, and then determined if a change in the context state would invoke switching between the adapted states. Horizontal and vertical eye position and head orientation could serve, to varying degrees, as cues for switching between two different saccade gains. In the present study, we asked whether gravity magnitude could serve as a context cue: saccade adaptation was performed during parabolic flight, which provides alternating levels of gravitoinertial force (0 g and 1.8 g). Results were less robust than those from ground experiments, but established that different saccade magnitudes could be associated with different gravity levels.

  11. Predicting FCI gain with a nonverbal intelligence test

    NASA Astrophysics Data System (ADS)

    Semak, M. R.; Dietz, R. D.; Pearson, R. H.; Willis, C. W.

    2013-01-01

    We have administered both a commercial, nonverbal intelligence test (the GAMA) and Lawson's Classroom Test of Scientific Reasoning to students in two introductory physics classes to determine if either test can successfully predict normalized gains on the Force Concept Inventory. Since gain on the FCI is known to be related to gender, we adopted a linear model with gain on the FCI as the dependent variable and gender and a test score as the independent variables. We found that the GAMA score did not predict a significant amount of variation beyond gender. Lawson's test, however, did predict a small but significant variation beyond gender. When simple linear regressions were run separately for males and females with the Lawson score as a predictor, we found that the Lawson score did not significantly predict gains for females but was a marginally significant predictor for males.

  12. Gas gain stabilisation in the ATLAS TRT detector

    NASA Astrophysics Data System (ADS)

    Mindur, B.; Åkesson, T. P. A.; Anghinolfi, F.; Antonov, A.; Arslan, O.; Baker, O. K.; Banas, E.; Bault, C.; Beddall, A. J.; Bendotti, J.; Benjamin, D. P.; Bertelsen, H.; Bingul, A.; Bocci, A.; Boldyrev, A. S.; Brock, I.; Capeáns Garrido, M.; Catinaccio, A.; Celebi, E.; Cetin, S. A.; Choi, K.; Dam, M.; Danielsson, H.; Davis, D.; Degeorge, C.; Derendarz, D.; Desch, K.; Di Girolamo, B.; Dittus, F.; Dixon, N.; Dressnandt, N.; Dubinin, F. A.; Evans, H.; Farthouat, P.; Fedin, O. L.; Froidevaux, D.; Gavrilenko, I. L.; Gay, C.; Gecse, Z.; Godlewski, J.; Grefe, C.; Gurbuz, S.; Hajduk, Z.; Hance, M.; Haney, B.; Hansen, J. B.; Hansen, P. H.; Hawkins, A. D.; Heim, S.; Holway, K.; Kantserov, V. A.; Katounine, S.; Kayumov, F.; Keener, P. T.; Kisielewski, B.; Klopov, N. V.; Konovalov, S. P.; Koperny, S.; Korotkova, N. A.; Kowalski, T. Z.; Kramarenko, V.; Krasnopevtsev, D.; Kruse, M.; Kudin, L. G.; Lichard, P.; Loginov, A.; Martinez, N. Lorenzo; Lucotte, A.; Luehring, F.; Lytken, E.; Maleev, V. P.; Maevskiy, A. S.; Manjarres Ramos, J.; Mashinistov, R. Y.; Meyer, C.; Mialkovski, V.; Mistry, K.; Mitsou, V. A.; Nadtochi, A. V.; Newcomer, F. M.; Novodvorski, E. G.; Ogren, H.; Oh, S. H.; Oleshko, S. B.; Olszowska, J.; Ostrowicz, W.; Palacino, G.; Patrichev, S.; Penwell, J.; Perez-Gomez, F.; Peshekhonov, V. D.; RØhne, O.; Reilly, M. B.; Rembser, C.; Ricken, O.; Romaniouk, A.; Rousseau, D.; Ryjov, V.; Sasmaz, U.; Schaepe, S.; Schegelsky, V. A.; Shmeleva, A. P.; Shulga, E.; Sivoklokov, S.; Smirnov, S.; Smirnov, Yu.; Smirnova, L. N.; Soldatov, E.; Sulin, V. V.; Tartarelli, G.; Taylor, W.; Thomson, E.; Tikhomirov, V. O.; Tipton, P.; Valls Ferrer, J. A.; Van Berg, R.; Vasquez, J.; Vasilyeva, L. F.; Vlazlo, O.; Weinert, B.; Williams, H. H.; Wong, V.; Zhukov, K. I.; Zieminska, D.

    2016-04-01

    The ATLAS (one of two general purpose detectors at the LHC) Transition Radiation Tracker (TRT) is the outermost of the three tracking subsystems of the ATLAS Inner Detector. It is a large straw-based detector and contains about 350,000 electronics channels. The performance of the TRT as tracking and particularly particle identification detector strongly depends on stability of the operation parameters with most important parameter being the gas gain which must be kept constant across the detector volume. The gas gain in the straws can vary significantly with atmospheric pressure, temperature, and gas mixture composition changes. This paper presents a concept of the gas gain stabilisation in the TRT and describes in detail the Gas Gain Stabilisation System (GGSS) integrated into the Detector Control System (DCS). Operation stability of the GGSS during Run-1 is demonstrated.

  13. Weight gain after quitting smoking: What to do

    MedlinePlus

    ... are a couple of reasons why people gain weight when they give up cigarettes. Some have to do with the way nicotine affects your body. The nicotine in cigarettes speeds up your metabolism. Nicotine increases the amount of ...

  14. What next for gain-of-function research in Europe?

    PubMed Central

    Fears, Robin; ter Meulen, Volker

    2015-01-01

    A working group on gain-of-function research set up by the European Academies Science Advisory Council (EASAC) has emphasised the importance of ensuring that the necessary safeguards and policies are in place PMID:26716473

  15. What next for gain-of-function research in Europe?

    PubMed

    Fears, Robin; ter Meulen, Volker

    2015-01-01

    A working group on gain-of-function research set up by the European Academies Science Advisory Council (EASAC) has emphasised the importance of ensuring that the necessary safeguards and policies are in place. PMID:26716473

  16. ELT antenna gain distributions under simulated crash conditions

    NASA Technical Reports Server (NTRS)

    Estep, H.

    1984-01-01

    A study of the relative merits of ELT antenna positions, when mounted on a small aircraft, is presented. The gain distribution of the best antenna position together with the worst crash scenario is also given.

  17. Gain-assisted control of the Goos-Haenchen shift

    SciTech Connect

    Ziauddin,; Qamar, Sajid

    2011-11-15

    A gain-assisted model is considered to study the Goos-Haenchen (GH) shift behavior in the reflected and transmitted light. In this model, a probe light is incident on a cavity containing three-level dilute gaseous atomic medium. The atom-field interaction follows two-photon Raman transitions, and the dielectric susceptibility of the medium exhibits dispersion and gain properties [L. J. Wang, A. Kuzmich, and A. Dogariu, Nature (London) 406, 227 (2000)]. Under appropriate conditions, two gain peaks are observed with anomalous dispersion between the peaks, whereas normal dispersion can be observed at and around the gain maxima. The manipulation of the detuning associated with the probe light field which interacts with the intracavity medium during its propagation through the cavity can lead to a control over negative and positive GH shift in the reflected and transmitted light beam via the anomalous and normal dispersion of the medium.

  18. Effect of surfactants on weight gain in mice.

    PubMed

    Kaneene, J B; Ross, R W

    1986-03-01

    A study was conducted to determine if four surfactants can induce increased weight gain in the mouse. Basic-H, Triton X-100, Amway All Purpose Adjuvant and X-77 were put in water and fed to various groups of ICR 21 day old female mice for a period of 43 days. All the mice were clinically normal throughout the study period. Pathological examination of a random sample of the mice revealed no gross pathological changes. Similarly, histopathological examination of the lungs, livers and intestines did not reveal any visible lesions. Basic-H and Amway surfactants induced weight gain, though not significantly, better at 0.1% (V/V) concentration while X-77 and Triton X-100 induced weight gain better at 0.4% (V/V) concentration. Overall results show that none of the surfactants tested induced significant weight gain.

  19. Recent Progress in High-Gain FEL Theory

    SciTech Connect

    Huang, Z.; /SLAC

    2005-09-30

    High-gain free electron lasers (FEL) are being developed as extremely bright x-ray sources of a next-generation radiation facility. In this paper, we review the basic theory and the recent progress in understanding the startup, the exponential growth and the saturation of the high-gain process, emphasizing the self-amplified spontaneous emission (SASE). We will also discuss how the FEL performance may be affected by various errors and wakefield effects in the undulator.

  20. Neighborhood socioeconomic disadvantage and gestational weight gain and loss

    PubMed Central

    Mendez, Dara D.; Doebler, Donna Almario; Kim, Kevin H.; Amutah, Ndidi N.; Fabio, Anthony; Bodnar, Lisa M.

    2013-01-01

    Objective We explored the relationship between neighborhood socioeconomic disadvantage (NSED) and gestational weight gain and loss and if the association differed by race. Methods A census tract level NSED index (categorized as low, mid-low, mid-high, and high) was generated from 12 measures from the 2000 US Census data. Gestational weight gain and other individual-level characteristics were derived from vital birth records for Allegheny County, PA for 2003–2010 (n=55,608). Crude and adjusted relative risks were estimated using modified multilevel Poisson regression models to estimate the association between NSED and excessive and inadequate gestational weight gain (GWG) and weight loss (versus adequate GWG). Results Black women lived in neighborhoods that were more likely to be socioeconomically disadvantaged compared to white women. Almost 55% of women gained an excessive amount of weight during pregnancy, and 2% lost weight during pregnancy. Black women were more likely than white women to have inadequate weight gain or weight loss. Mid-high (aRR=1.3, 95% CI: 1.2, 1.3) and high (aRR=1.5, 95% CI: 1.5, 1.6) NSED compared to low NSED was associated with inadequate weight gain while NSED was not associated with excessive weight gain. Among black women, high versus low NSED was associated with weight loss during pregnancy (RR=1.6; 95% CI: 1.1, 2.5). Among white women, each level of NSED compared to low NSED was associated with weight loss during pregnancy. Conclusion This study demonstrates how neighborhood socioeconomic characteristics can contribute to our understanding of inadequate weight gain and weight loss during pregnancy, having implications for future research and interventions designed to advance pregnancy outcomes. PMID:24026397

  1. Multiple socioeconomic determinants of weight gain: the Helsinki Health Study

    PubMed Central

    2013-01-01

    Background Socioeconomic differences in weight gain have been found, but several socioeconomic determinants have not been simultaneously studied using a longitudinal design. The aim of this study was to examine multiple socioeconomic determinants of weight gain. Methods Mail surveys were conducted in 2000–2002 among 40 to 60-year old employees of the City of Helsinki, Finland (n = 8 960, response rate 67%). A follow-up survey was conducted among the baseline respondents in 2007 with a mean follow-up of 5 to 7 years (n = 7 332, response rate 83%). The outcome measure was weight gain of 5 kg or more over the follow-up. Socioeconomic position was measured by parental education, childhood economic difficulties, own education, occupational class, household income, home ownership and current economic difficulties. Multivariable logistic regression models were fitted adjusting simultaneously for all covariates in the final model. Results Of women 27% and of men 24% gained 5 kg or more in weight over the follow-up. Among women, after adjusting for age, baseline weight and all socioeconomic determinants, those with basic (OR 1.40 95% CI 1.11-1.76) or intermediate education (OR 1.43 95% CI 1.08-1.90), renters (OR 1.18 95% CI 1.03-1.36) and those with occasional (OR 1.19 95% CI 1.03-1.38) or frequent (OR 1.50 95% CI 1.26-1.79) economic difficulties had increased risk of weight gain. Among men, after full adjustment, having current frequent economic difficulties (OR 1.70 95% CI 1.15-2.49) remained associated with weight gain. Conclusions Current economic difficulties among both women and men, and among women low education and renting, were associated with weight gain. Prevention of weight gain among ageing people would benefit from focusing in particular on those with economic difficulties. PMID:23517457

  2. Gain competition in dual wavelength quantum cascade lasers.

    PubMed

    Geiser, Markus; Pflügl, Christian; Belyanin, Alexey; Wang, Qi Jie; Yu, Nanfang; Edamura, Tadanaka; Yamanishi, Masamichi; Kan, Hirofumi; Fischer, Milan; Wittmann, Andreas; Faist, Jérôme; Capasso, Federico

    2010-05-10

    We investigated dual wavelength mid-infrared quantum cascade lasers based on heterogeneous cascades. We found that due to gain competition laser action tends to start in higher order lateral modes. The mid-infrared mode with the lower threshold current reduces population inversion for the second laser with the higher threshold current due to stimulated emission. We developed a rate equation model to quantitatively describe mode interactions due to mutual gain depletion.

  3. Computer simulation of space station computer steered high gain antenna

    NASA Technical Reports Server (NTRS)

    Beach, S. W.

    1973-01-01

    The mathematical modeling and programming of a complete simulation program for a space station computer-steered high gain antenna are described. The program provides for reading input data cards, numerically integrating up to 50 first order differential equations, and monitoring up to 48 variables on printed output and on plots. The program system consists of a high gain antenna, an antenna gimbal control system, an on board computer, and the environment in which all are to operate.

  4. High gain amplifiers: Power oscillations and harmonic generation

    SciTech Connect

    Dattoli, G.; Ottaviani, P. L.; Pagnutti, S.

    2007-08-01

    We discuss the power oscillations in saturated high gain free electron laser amplifiers and show that the relevant period can be written in terms of the gain length. We use simple arguments following from the solution of the pendulum equation in terms of Jacobi elliptic functions. Nontrivial effects due to nonlinear harmonic generation and inhomogeneous broadening are discussed too, as well as the saturated dynamics of short pulses.

  5. Gain compression effect on the modulation dynamics of an optically injection-locked semiconductor laser using gain lever

    NASA Astrophysics Data System (ADS)

    Sarraute, J.-M.; Schires, K.; LaRochelle, S.; Grillot, F.

    2016-03-01

    The modulation response of an optically-injected gain lever semiconductor laser is studied and calculations show that a gain-lever laser operating under medium to strong optical injection provides a unique and robust configuration for ultra large bandwidth enhancement. Modulation bandwidths above nine times the relaxation oscillation frequency of the free-running laser can be reached using injection-locking conditions that are reasonable for practical applications. The impact of the gain compression on the modulation dynamic is discussed for the first time. This work is of prime importance for the development of directly-modulated broadband optical sources for high-speed operation at 40 Gbps and beyond.

  6. Gains in accuracy from averaging ratings of abnormality

    NASA Astrophysics Data System (ADS)

    Swensson, Richard G.; King, Jill L.; Gur, David; Good, Walter F.

    1999-05-01

    Six radiologists used continuous scales to rate 529 chest-film cases for likelihood of five separate types of abnormalities (interstitial disease, nodules, pneumothorax, alveolar infiltrates and rib fractures) in each of six replicated readings, yielding 36 separate ratings of each case for the five abnormalities. Analyses for each type of abnormality estimated the relative gains in accuracy (area below the ROC curve) obtained by averaging the case-ratings across: (1) six independent replications by each reader (30% gain), (2) six different readers within each replication (39% gain) or (3) all 36 readings (58% gain). Although accuracy differed among both readers and abnormalities, ROC curves for the median ratings showed similar relative gains in accuracy. From a latent-variable model for these gains, we estimate that about 51% of a reader's total decision variance consisted of random (within-reader) errors that were uncorrelated between replications, another 14% came from that reader's consistent (but idiosyncratic) responses to different cases, and only about 35% could be attributed to systematic variations among the sampled cases that were consistent across different readers.

  7. Streamflow gain and loss of selected streams in northern Arkansas

    USGS Publications Warehouse

    Freiwald, David A.

    1987-01-01

    This map shows streamflow gain and loss measurements (seepage runs) on the Crooked, Osage, and Spavinaw Creeks, and Illinois, Kings, Mulberry, Spring, and Strawberry Rivers during the low-flow conditions from September 1982 to October 1984. Data indicated that streamflow gains and losses resulted from differences in lithology of the predominately carbonate rocks and from the presence of faults. The Kings and Strawberry Rivers and Osage Creek were gaining streams throughout their length, however wastewater discharges precluded an accurate determination on Osage Creek. Crooked and Spavinaw Creeks and the Illinois, Spring, and Mulberry Rivers generally were gaining streams throughout most of their lengths although short losing reaches were identified. The largest gains in streamflow generally occurred were Mississippian formation predominated near the streams. Faults that intersected the stream channels primarily were responsible for streamflow losses. The specific conductance of water increased in the stream reaches that had the most significant streamflow gains. The specific conductance of water in tributaries was generally higher than that in larger streams. (Author 's abstract)

  8. The influence of gain nonlinearities on distortion in semiconductor lasers

    NASA Astrophysics Data System (ADS)

    Lysak, Vladimir V.; Schatz, Richard; Shulika, Aleksey V.; Sukhoivanov, Igor A.; Kjebon, O.

    2004-09-01

    The semiconductor laser is commonly used as a light source in fiber-optical telecommunication systems. In order to send as much information as possible in a short time, it is important that the laser has a large modulation bandwidth, i.e., the turn-on and turn-off time should be as short as possible. In analogue fiber optic systems for transmission of radio or television signals, it is also important that the light from the laser increases linearly with driving current even at high modulation frequencies. Otherwise, the transmitted signal will become distorted. The modulation bandwidth and the modulation distortion are dependent both on the laser structure and the gain characteristics of the active material. One of the most useful approaches for the time-domain description of the response of optoelectronic devices is the so-called "rate equation model," which has been widely used to describe laser performance. Commonly, laser models with simple gain expressions are used for simulation of laser dynamics. In these models the small-signal dynamic parameters like the differential gain and gain saturation parameter are extracted from modulation response measurements. However, we show that in order to correctly calculate distortion, an accurate model of the dependence of gain on carrier density, n, and photon density, s, is needed. Commonly used gain models, fitted to give exactly the same modulation response can give significantly different distortion behavior.

  9. Gain saturation in InGaN superluminescent diodes

    NASA Astrophysics Data System (ADS)

    Kafar, Anna; Stanczyk, Szymon; Targowski, Grzegorz; Suski, Tadek; Perlin, Piotr

    2014-03-01

    The gain saturation is a crucial factor limiting achievable output power of superluminescent diodes (SLD), as it exponentially depends on optical gain value. Contrary to laser diodes, in SLDs gain is increasing with the increasing current even much above the transparency conditions. Therefore, SLDs provide us with an unique possibility to examine gain under high current densities (high carrier injection). In our work we examined SLDs fabricated in a "j-shape" ridge-waveguide geometry having chips of the length of 700 μm and 1000 μm, emitting in the blue-violet region. By comparing the amplified spontaneous emission measured along the device waveguide with true spontaneous emission measured in perpendicular direction, we are able to extract optical gain as a function of injected current. We show, that in our devices spontaneous emission exhibits a square-root-like dependence on current which is commonly associated with the presence of "droop" in case of nitride light emitting diodes. However, along the waveguide axis, fast processes of stimulated recombination dominate which eliminates the efficiency reduction. Calculated optical gain shows a substantial saturation for current densities above 8 kA/cm2.

  10. New recommended heat gains for commercial cooking equipment

    SciTech Connect

    Fisher, D.R.

    1998-12-31

    Radiant heat gain from cooking equipment can significantly impact the air-conditioning load and/or human comfort in a commercial kitchen. This paper presents and discusses updated heat gain data for several types of commercial cooking equipment based on recent testing by gas and electric utility research organizations. The cooking equipment was tested under exhaust-only, wall-canopy hoods. The fundamentals of appliance heat gain are reviewed and the new data are compared with data published in the 1993 ASHRAE Handbook--Fundamentals, chapter 26, nonresidential cooling and heating load calculations. These updated data are now incorporated in the 1997 ASHRAE Handbook--Fundamentals, chapter 28, nonresidential cooling and heating load calculations. The paper also discusses appliance heat gain with respect to sizing air-conditioning systems for commercial kitchens and presents representative radiant factors that may be used to estimate heat gain from other sizes or types of gas and electric cooking equipment when appliance specific heat gain data are not avoidable.

  11. Resonant measurements of nonlinear lensing in a VECSEL gain sample

    NASA Astrophysics Data System (ADS)

    Quarterman, Adrian H.; Smyth, Conor J. C.; Mirkhanov, Shamil; Wilcox, Keith G.

    2016-03-01

    In recent years there have been several reports describing self-modelocking (SML) in vertical-external-cavity surfaceemitting lasers (VECSELs). Some of these reports have suggested that the behaviour that has been observed results from nonlinear lensing in the VECSEL gain sample in a manner analogous to Kerr lens modelocking in solid state lasers. However to date none of the groups that have reported SML in VECSELs have performed measurements to ascertain whether nonlinear lensing occurs in the gain sample. Measurements of nonlinear lenses in VECSEL gain samples are therefore of value not only in order to understand the behaviour observed in the reports of SML, but also as a potentially crucial design tool for any mode-locked VECSEL, regardless of the modelocking method used. In a previous publication we described measurements which demonstrated that a defocusing nonlinear lens was present in an unpumped VECSEL gain sample, and that the inverse focal length of the lens increased with pump power, to the point of becoming a focusing lens for sufficiently high pump powers. Unfortunately, by necessity this measurement was performed using a probe laser which was not resonant with the quantum wells in the sample, meaning that the values measured may well be different from those experienced under operating conditions in a VECSEL. This paper describes a more complete characterisation of VECSEL gain sample nonlinear lensing with a probe laser whose wavelength is resonant with the gain sample quantum wells.

  12. Dieting: proxy or cause of future weight gain?

    PubMed

    Lowe, M R

    2015-02-01

    The relationship between dieting and body mass has a long and controversial history. This paper aims to help resolve this issue by making two key distinctions. The first is between dieting as a cause of weight gain/regain and as a proxy risk factor for identifying non-obese individuals prone to weight gain for reasons other than dieting. The second is between the body mass that is attained following one or more weight loss/regain cycles and the body mass that might have been reached had dieting never been undertaken. Evidence is reviewed on the relation between recent diet-induced weight loss and sustained weight loss (weight suppression), on the one hand, and weight regain, on the other hand. Furthermore, the reason that a history of dieting in non-obese individuals reflects a susceptibility to future weight gain is explained. It is concluded that (i) diet-induced weight loss hastens weight regain but a history of weight loss diets does not cause weight gain beyond that which would occur in the absence of dieting, and (ii) weight loss dieting in non-obese individuals does not cause future weight gain but is simply a proxy risk factor reflecting a personal vulnerability to weight gain and living in an obesogenic environment. PMID:25614200

  13. Sub-250nm room temperature optical gain from AlGaN materials with strong compositional fluctuations

    NASA Astrophysics Data System (ADS)

    Pecora, Emanuele; Zhang, Wei; Sun, Haiding; Nikiforov, A.; Yin, Jian; Paiella, Roberto; Moustakas, Theodore; Dal Negro, Luca

    2013-03-01

    Compact and portable deep-UV LEDs and laser sources are needed for a number of engineering applications including optical communications, gas sensing, biochemical agent detection, disinfection, biotechnology and medical diagnostics. We investigate the deep-UV optical emission and gain properties of AlxGa1-xN/AlyGa1-yN multiple quantum wells structure. These structures were grown by molecular-beam epitaxy on 6H-SiC substrates resulting in either homogeneous wells or various degrees of band-structure compositional fluctuations in the form of cluster-like features within the wells. We measured the TE-polarized amplified spontaneous emission in the sample with cluster-like features and quantified the optical absorption/gain coefficients and gain spectra by the Variable Stripe Length (VSL) technique under ultrafast optical pumping. We report blue-shift and narrowing of the emission, VSL traces, gain spectra, polarization studies, and the validity of the Schalow-Townes relation to demonstrate a maximum net modal gain of 120 cm-1 at 250 nm in the sample with strong compositional fluctuations. Moreover, we measure a very low gain threshold (15 μJ/cm2) . On the other hand, we found that samples with homogeneous quantum wells lead to absorption only. In addition, we report gain measurements in graded-index-separate-confined heterostructure (GRINSCH) designed to increase the device optical confinement factor.

  14. Investigation of gain enhancement of electrically small antennas using double-negative, single-negative, and double-positive materials.

    PubMed

    Ghosh, B; Ghosh, S; Kakade, A B

    2008-08-01

    In this paper, it is shown that a double-negative or a mu-negative shell can be used to achieve a very high gain for an electrically small loop. It is also seen that together with the high gain, the metamaterial shell can be used to achieve a very uniform gain characteristic with respect to the shell dimensions. This is accomplished by a proper choice of the media parameters of the metamaterial shell and the region surrounding the antenna. This significantly eases the fabrication constraints and the close tolerances on the shell which was a major drawback towards the practical realization of the shell. Also, significant power gain can be obtained when the radiated power from the metamaterial shell is compared to the power radiated by a loop of the same radius as the outer radius of the shell. In addition, it is also found that a double-positive shell of the same dimensions as the metamaterial shell can be used to significantly increase the gain of the infinitesimal antenna. The power gain characteristics show distinct resonant peaks in this case. Excellent matching characteristics are observed corresponding to the radiated power gain.

  15. Sweet taste of saccharin induces weight gain without increasing caloric intake, not related to insulin-resistance in Wistar rats.

    PubMed

    Foletto, Kelly Carraro; Melo Batista, Bruna Aparecida; Neves, Alice Magagnin; de Matos Feijó, Fernanda; Ballard, Cíntia Reis; Marques Ribeiro, Maria Flávia; Bertoluci, Marcello Casaccia

    2016-01-01

    In a previous study, we showed that saccharin can induce weight gain when compared with sucrose in Wistar rats despite similar total caloric intake. We now question whether it could be due to the sweet taste of saccharin per se. We also aimed to address if this weight gain is associated with insulin-resistance and to increases in gut peptides such as leptin and PYY in the fasting state. In a 14 week experiment, 16 male Wistar rats received either saccharin-sweetened yogurt or non-sweetened yogurt daily in addition to chow and water ad lib. We measured daily food intake and weight gain weekly. At the end of the experiment, we evaluated fasting leptin, glucose, insulin, PYY and determined insulin resistance through HOMA-IR. Cumulative weight gain and food intake were evaluated through linear mixed models. Results showed that saccharin induced greater weight gain when compared with non-sweetened control (p = 0.027) despite a similar total caloric intake. There were no differences in HOMA-IR, fasting leptin or PYY levels between groups. We conclude that saccharin sweet taste can induce mild weight gain in Wistar rats without increasing total caloric intake. This weight gain was not related with insulin-resistance nor changes in fasting leptin or PYY in Wistar rats.

  16. Transient gain-absorption of the probe field in triple quantum dots coupled by double tunneling

    NASA Astrophysics Data System (ADS)

    Tian, Si-Cong; Zhang, Xiao-Jun; Wan, Ren-Gang; Zhao, Shuai; Wu, Hao; Shu, Shi-Li; Wang, Li-Jie; Tong, Cun-Zhu

    2016-06-01

    The transient gain-absorption property of the probe field in a linear triple quantum dots coupled by double tunneling is investigated. It is found that the additional tunneling can dramatically affect the transient behaviors under the transparency condition. The dependence of transient behaviors on other parameters, such as probe detuning, the pure dephasing decay rate of the quantum dots and the initial conditions of the population, are also discussed. The results can be explained by the properties of the dressed states generated by the additional tunneling. The scheme may have important application in quantum information network and communication.

  17. Graphene Distributed Amplifiers: Generating Desirable Gain for Graphene Field-Effect Transistors

    PubMed Central

    Lyu, Hongming; Lu, Qi; Huang, Yilin; Ma, Teng; Zhang, Jinyu; Wu, Xiaoming; Yu, Zhiping; Ren, Wencai; Cheng, Hui-Ming; Wu, Huaqiang; Qian, He

    2015-01-01

    Ever since its discovery, graphene bears great expectations in high frequency electronics due to its irreplaceably high carrier mobility. However, it has long been blamed for the weakness in generating gains, which seriously limits its pace of development. Distributed amplification, on the other hand, has successfully been used in conventional semiconductors to increase the amplifiers’ gain-bandwidth product. In this paper, distributed amplification is first applied to graphene. Transmission lines phase-synchronize paralleled graphene field-effect transistors (GFETs), combining the gain of each stage in an additive manner. Simulations were based on fabricated GFETs whose fT ranged from 8.5 GHz to 10.5 GHz and fmax from 12 GHz to 14 GHz. A simulated four-stage graphene distributed amplifier achieved up to 4 dB gain and 3.5 GHz bandwidth, which could be realized with future IC processes. A PCB level graphene distributed amplifier was fabricated as a proof of circuit concept. PMID:26634442

  18. Large Optical Gain AlInN-Delta-GaN Quantum Well for Deep Ultraviolet Emitters

    PubMed Central

    Tan, Chee-Keong; Sun, Wei; Borovac, Damir; Tansu, Nelson

    2016-01-01

    The optical gain and spontaneous emission characteristics of low In-content AlInN-delta-GaN quantum wells (QWs) are analyzed for deep ultraviolet (UV) light emitting diodes (LEDs) and lasers. Our analysis shows a large increase in the dominant transverse electric (TE) polarized spontaneous emission rate and optical gain. The remarkable enhancements in TE-polarized optical gain and spontaneous emission characteristics are attributed to the dominant conduction (C)-heavy hole (HH) transitions achieved by the AlInN-delta-GaN QW structure, which could lead to its potential application as the active region material for high performance deep UV emitters. In addition, our findings show that further optimizations of the delta-GaN layer in the active region are required to realize the high performance AlInN-based LEDs and lasers with the desired emission wavelength. This work illuminates the high potential of the low In-content AlInN-delta-GaN QW structure to achieve large dominant TE-polarized spontaneous emission rates and optical gains for high performance AlN-based UV devices. PMID:26961170

  19. Pregnant women's perceptions of weight gain, physical activity, and nutrition using Theory of Planned Behavior constructs.

    PubMed

    Whitaker, Kara M; Wilcox, Sara; Liu, Jihong; Blair, Steven N; Pate, Russell R

    2016-02-01

    A better understanding of women's perceptions of weight gain and related behaviors during pregnancy is necessary to inform behavioral interventions. We used the Theory of Planned Behavior (TPB) to examine pregnant women's perceptions and intentions toward weight gain, physical activity (PA), and nutrition using a mixed methods study design. Women between 20 and 30 weeks gestation (n = 189) were recruited to complete an Internet-based survey. Salient beliefs toward weight gain, PA, and nutrition were captured through open-ended responses and content analyzed into themes. TPB constructs (attitude, subjective norm, perceived behavioral control, intentions) were examined using Pearson correlations and hierarchical linear regression models. Salient beliefs were consistent with the existing literature in non-pregnant populations, with the addition of many pregnancy-specific beliefs. TPB constructs accounted for 23-39 % of the variance in weight gain, PA, and nutrition intentions, and made varying contributions across outcomes. The TPB is a useful framework for examining women's weight-related intentions during pregnancy. Study implications for intervention development are discussed.

  20. Gain dynamics in Er(3+):Yb(+) co-doped fiber amplifiers.

    PubMed

    Steinke, M; Neumann, J; Kracht, D; Wessels, P

    2015-06-01

    Understanding the gain dynamics of fiber amplifiers is essential for the implementation and active stabilization of low noise amplifiers or for coherent beam combining schemes. The gain dynamics of purely Er3+ or Yb3+ doped fiber amplifiers are well studied, whereas no analysis for co-doped systems, especially for Er3+:Yb3+ co-doped fiber amplifiers has been performed, so far. Here, we analyze for the first time the gain dynamics of Er3+:Yb3+ co-doped fiber amplifiers theoretically and experimentally. It is shown that due to the energy transfer between the Yb3+ and Er3+ ions a full analytical solution is not possible. Thus, we used numerical simulations to gain further insights. Comparison of experimental and numerical results shows good qualitative agreement. In addition, we were able to determine the Yb3+-Er3+ transfer function of the energy transfer experimentally.

  1. Large Optical Gain AlInN-Delta-GaN Quantum Well for Deep Ultraviolet Emitters.

    PubMed

    Tan, Chee-Keong; Sun, Wei; Borovac, Damir; Tansu, Nelson

    2016-01-01

    The optical gain and spontaneous emission characteristics of low In-content AlInN-delta-GaN quantum wells (QWs) are analyzed for deep ultraviolet (UV) light emitting diodes (LEDs) and lasers. Our analysis shows a large increase in the dominant transverse electric (TE) polarized spontaneous emission rate and optical gain. The remarkable enhancements in TE-polarized optical gain and spontaneous emission characteristics are attributed to the dominant conduction (C)-heavy hole (HH) transitions achieved by the AlInN-delta-GaN QW structure, which could lead to its potential application as the active region material for high performance deep UV emitters. In addition, our findings show that further optimizations of the delta-GaN layer in the active region are required to realize the high performance AlInN-based LEDs and lasers with the desired emission wavelength. This work illuminates the high potential of the low In-content AlInN-delta-GaN QW structure to achieve large dominant TE-polarized spontaneous emission rates and optical gains for high performance AlN-based UV devices.

  2. Gain control dynamics of thulium-doped fiber amplifier at 2 μm

    NASA Astrophysics Data System (ADS)

    Khamis, M. A.; Ennser, K.

    2016-02-01

    This work is novel in that it explains the modeling and simulation of a thulium-doped fiber amplifier (TDFA) in a reconfigurable wavelength division multiplexing (WDM) system operating at 2 μm. We use the optical gain-clamping technique in order to control gain amplification and eliminate deleterious channel power fluctuations resulting from input power variation at the TDFA. The investigated system consists of 12 channels with -4 dBm total input power. Simulation results indicate that approximately1.5dB power excursion is produced after dropping 11 channels in unclamped-gain amplifier, and only 0.005 dB in a clamped-gain amplifier. Additionally, a clamped configuration brings the power excursion from 4.2 dB to under 0.08 dB, after adding 11 channels to the investigated system. Hence, optical gainclamping is a simple and robust technique for controlling the power transient in amplifiers at 2 μm.

  3. Cost-effectiveness analysis of anastrozole vs tamoxifen in adjuvant therapy for early stage breast cancer in the United Kingdom: the 5-year completed treatment analysis of the ATAC (‘Arimidex', Tamoxifen alone or in combination) trial

    PubMed Central

    Mansel, R; Locker, G; Fallowfield, L; Benedict, Á; Jones, D

    2007-01-01

    Results from the completed treatment analysis of the ATAC (Arimidex, Tamoxifen alone or in combination) trial indicated that anastrozole was significantly superior to tamoxifen in terms of efficacy and safety in the adjuvant treatment of postmenopausal women with hormone receptor-positive (HR+) early breast cancer. On the basis of these results, this study estimated the cost-effectiveness of anastrozole vs tamoxifen, from the perspective of the UK National Health Service (NHS). A Markov model was developed using the 5-year completed treatment analysis from the ATAC trial (ISRCTN18233230), as well as data obtained from published literature and expert opinion. Resource utilisation data and associated costs (2003–4 UK£) were compiled from standard sources and expert opinion. Utility scores for a number of health states were obtained from a cross-sectional study of 26 representative patients using the standard gamble technique. The utility scores were then inserted into the model to obtain cost per quality adjusted life-year (QALY) gained. Costs and benefits were discounted at recommended annual rates of the UK Treasury (3.5%). Modelled for 25 years, anastrozole, relative to generic tamoxifen, was estimated to result in 0.244 QALYs gained per patient at an additional cost of £4315 per patient). The estimated incremental cost-effectiveness of anastrozole compared with tamoxifen was £17 656 per QALY gained. There was a greater than 90% probability that the cost-effectiveness of anastrozole was below £30 000 per QALY gained and of the order of 65% that it was below £20 000 per QALY gained. The results were robust to all parameters tested in sensitivity analysis. Compared with commonly accepted thresholds, anastrozole is a cost-effective alternative to generic tamoxifen in adjuvant treatment of postmenopausal women with HR+ early breast cancer from the UK NHS perspective. PMID:17622238

  4. Enhancement of stimulated Raman scattering of weak-gain Raman modes in a pendant drop by dye-lasing gain

    NASA Astrophysics Data System (ADS)

    Pu, Xiao-Yun; Yang, Zheng; Lee, Wing-Kee

    2004-02-01

    The enhancement of stimulated Raman scattering (SRS) of weak-gain Raman modes in pendant drops is accomplished by overlapping Stokes wavelengths of the Raman modes with the Rhodamine 640 dye-lasing gain region (called the gain-overlap method). The dye concentration and the pumping intensity of frequency-doubled Nd:YAG lasers determine the efficiency of the enhancement. We apply the gain-overlap technique at optimal dye concentration and pump intensity to probe minority species in pendant drops formed by binary mixtures. The limits of detectable concentrations of the minority species, methanol in methanol-ethanol and ethanol in ethanol-water (dye-doped) mixtures, are much less than those in undoped mixtures. The smooth fluorescence-lasing spectral curves emitted from dye-doped pendant drops reduce complications in distinguishing SRS signals from quasi-periodic fluorescence-lasing spectra in microdroplets.

  5. Incorporation of additives into polymers

    DOEpatents

    McCleskey, T. Mark; Yates, Matthew Z.

    2003-07-29

    There has been invented a method for incorporating additives into polymers comprising: (a) forming an aqueous or alcohol-based colloidal system of the polymer; (b) emulsifying the colloidal system with a compressed fluid; and (c) contacting the colloidal polymer with the additive in the presence of the compressed fluid. The colloidal polymer can be contacted with the additive by having the additive in the compressed fluid used for emulsification or by adding the additive to the colloidal system before or after emulsification with the compressed fluid. The invention process can be carried out either as a batch process or as a continuous on-line process.

  6. Weight gain in smokers after quitting cigarettes: meta-analysis

    PubMed Central

    Farley, Amanda; Lycett, Deborah; Lahmek, Pierre; Aveyard, Paul

    2012-01-01

    Objective To describe weight gain and its variation in smokers who achieve prolonged abstinence for up to 12 months and who quit without treatment or use drugs to assist cessation. Design Meta-analysis. Data sources We searched the Central Register of Controlled Trials (CENTRAL) and trials listed in Cochrane reviews of smoking cessation interventions (nicotine replacement therapy, nicotinic partial agonists, antidepressants, and exercise) for randomised trials of first line treatments (nicotine replacement therapy, bupropion, and varenicline) and exercise that reported weight change. We also searched CENTRAL for trials of interventions for weight gain after cessation. Review methods Trials were included if they recorded weight change from baseline to follow-up in abstinent smokers. We used a random effects inverse variance model to calculate the mean and 95% confidence intervals and the mean of the standard deviation for weight change from baseline to one, two, three, six, and 12 months after quitting. We explored subgroup differences using random effects meta-regression. Results 62 studies were included. In untreated quitters, mean weight gain was 1.12 kg (95% confidence interval 0.76 to 1.47), 2.26 kg (1.98 to 2.54), 2.85 kg (2.42 to 3.28), 4.23 kg (3.69 to 4.77), and 4.67 kg (3.96 to 5.38) at one, two, three, six, and 12 months after quitting, respectively. Using the means and weighted standard deviations, we calculated that at 12 months after cessation, 16%, 37%, 34%, and 13% of untreated quitters lost weight, and gained less than 5 kg, gained 5-10 kg, and gained more than 10 kg, respectively. Estimates of weight gain were similar for people using different pharmacotherapies to support cessation. Estimates were also similar between people especially concerned about weight gain and those not concerned. Conclusion Smoking cessation is associated with a mean increase of 4-5 kg in body weight after 12 months of abstinence, and most weight gain occurs within three

  7. [Patch-testing methods: additional specialised or additional series].

    PubMed

    Cleenewerck, M-B

    2009-01-01

    The tests in the European standard battery must occasionally be supplemented by specialised or additional batteries, particularly where the contact allergy is thought to be of occupational origin. These additional batteries cover all allergens associated with various professional activities (hairdressing, baking, dentistry, printing, etc.) and with different classes of materials and chemical products (glue, plastic, rubber...). These additional tests may also include personal items used by patients on a daily basis such as cosmetics, shoes, plants, textiles and so on.

  8. Additive manufacturing of optical components

    NASA Astrophysics Data System (ADS)

    Heinrich, Andreas; Rank, Manuel; Maillard, Philippe; Suckow, Anne; Bauckhage, Yannick; Rößler, Patrick; Lang, Johannes; Shariff, Fatin; Pekrul, Sven

    2016-08-01

    The development of additive manufacturing methods has enlarged rapidly in recent years. Thereby, the work mainly focuses on the realization of mechanical components, but the additive manufacturing technology offers a high potential in the field of optics as well. Owing to new design possibilities, completely new solutions are possible. This article briefly reviews and compares the most important additive manufacturing methods for polymer optics. Additionally, it points out the characteristics of additive manufactured polymer optics. Thereby, surface quality is of crucial importance. In order to improve it, appropriate post-processing steps are necessary (e.g. robot polishing or coating), which will be discussed. An essential part of this paper deals with various additive manufactured optical components and their use, especially in optical systems for shape metrology (e.g. borehole sensor, tilt sensor, freeform surface sensor, fisheye lens). The examples should demonstrate the potentials and limitations of optical components produced by additive manufacturing.

  9. Indirect flat-panel detector with avalanche gain

    NASA Astrophysics Data System (ADS)

    Zhao, Wei; Hunt, Dylan C.; Tanioka, Kenkichi; Rowlands, John A.

    2004-05-01

    A new concept - an indirect flat-panel detector with avalanche gain - for low dose x-ray imaging has been proposed. The detector consists of an amorphous selenium (a-Se) photoconductor optically coupled to a structured cesium iodide (CsI) scintillator. Under an electric field ESe, the a-Se is sensitive to light and converts the optical photons emitted from CsI into electronic signal. These signals can be stored and read out in the same fashion as in existing flat-panel detectors. When ESe is increased to > 90 V/μm, avalanche multiplication occurs. The avalanche gain ranges between 1-800 depending on ESe and the thickness of the a-Se layer dSe. The avalanche a-Se photoconductor is referred to as HARP (High-gain Avalanche Rushing amorphous Photoconductor). A cascaded linear system model for the proposed detector was developed in order to determine the optimal CsI properties and avalanche gain for different x-ray imaging applications. Our results showed that x-ray quantum noise limited performance can be achieved at the lowest exposure level necessary for fluoroscopy (0.1 μR) and mammography (0.1 mR) with a moderate avalanche gain of 20 (d = 1-2 μm). A laboratory test system using an existing HARP tube optically coupled (through a lens) to a CsI layer was built and the advantage of avalanche gain in overcoming electronic noise was demonstrated experimentally. One of the advantages of the avalanche gain is that it will permit the use of high resolution (HR) CsI (which due to its low light output has not previously been used in flat-panel detectors) to improve DQE at high spatial frequencies.

  10. Maternal Prenatal Weight Gain and Autism Spectrum Disorders

    PubMed Central

    Bakian, Amanda V.; Viskochil, Joseph; Clark, Erin A.S.; Botts, Elizabeth L.; Smith, Ken R.; Pimentel, Richard; McMahon, William M.; Coon, Hilary

    2013-01-01

    BACKGROUND: The rising population of individuals identified with an autism spectrum disorder (ASD) calls for further investigation of its underlying etiology. A disturbance in the fetal steroid hormone environment may be a mechanism in which environmental and genetic risk factors interact. The mother, fetus, and placenta collectively create the fetal steroid environment. Prepregnancy BMI and pregnancy weight gain have served as markers for fetal steroid hormone exposure in other disease states. This study’s objective is to determine whether prepregnancy BMI and pregnancy weight gain are associated with increased ASD risk across study designs and cohorts while controlling for important confounding variables. METHODS: A population-based Utah ASD cohort (n = 128) was ascertained in a 3-county surveillance area and gender- and age-matched to 10 920 control subjects. A second, research-based ASD cohort of Utah children (n = 288) and their unaffected siblings (n = 493) were ascertained through participation in an ASD genetics study. Prenatal variables were obtained from birth certificate records. RESULTS: ASD risk was significantly associated with pregnancy weight gain (adjusted odds ratio = 1.10, 95% confidence interval: 1.03 to 1.17; adjusted odds ratio = 1.17, 95% confidence interval: 1.01 to 1.35 for each 5 pounds of weight gained), but not prepregnancy BMI, in population and research-based cohorts, respectively. When analyses were restricted to ASD cases with normal IQ, these associations remained significant. CONCLUSIONS: ASD risk associated with a modest yet consistent increase in pregnancy weight gain suggests that pregnancy weight gain may serve as an important marker for autism’s underlying gestational etiology. This justifies an investigation into phenomena that link pregnancy weight gain and ASD independent of prepregnancy BMI. PMID:24167172

  11. College weight gain and behavior transitions: male and female differences.

    PubMed

    Cluskey, Mary; Grobe, Deana

    2009-02-01

    College-student weight gain has been well-documented. However, little is known about the sex differences in weight gain and related behaviors during the transition to college. A repeated-measure study design was used to reveal measured weight changes from October to December 2005 among male and female college students. Three-hundred seventy-nine college students (60% males) participated in both weight assessments and revealed weight gains occurring early in college. Weight gains were found to be of greater incidence and magnitude among college males in the study. More than 25% of both college males and females gained >2.3 kg body weight in an 8-week period. Females starting the study with overweight and obese body mass index (calculated as kg/m(2)) scores were less likely to gain than either obese or overweight body mass index males or low to healthy body mass index students of both sexes. A life-course perspective was used to analyze focus group discussions conducted among students who participated in the weight assessments and explored their perceptions of the transition in eating and exercise behaviors when coming to college. Students described struggles in adapting healthful eating and exercise behaviors to college life. Comments indicated that while college student activity levels differed from the past, there was consistent agreement that eating healthful diets was perceived to be a greater challenge in the transition to college. Male students were less concerned about weight and used fewer strategies to control weight gain than females. More work is needed to understand the transition of behaviors and in developing healthful lifestyles during college.

  12. PDGFRA gain in low-grade diffuse gliomas.

    PubMed

    Motomura, Kazuya; Mittelbronn, Michel; Paulus, Werner; Brokinkel, Benjamin; Keyvani, Kathy; Sure, Ulrich; Wrede, Karsten; Nakazato, Yoichi; Tanaka, Yuko; Nonoguchi, Naosuke; Pierscianek, Daniela; Kim, Young-Ho; Mariani, Luigi; Vital, Anne; Perry, Arie; Ohgaki, Hiroko

    2013-01-01

    Glioblastomas with a proneural expression signature are characterized by frequent IDH1 mutations (i.e. genetic hallmarks of secondary glioblastomas) and PDGFRA (platelet-derived growth factor receptor-α) amplification. Mutations in IDH1/2 are frequent and early genetic events in diffuse astrocytomas (World Health Organization grade II), precursor to secondary glioblastomas, but little is known about the role and timing of PDGFRA amplification in these tumors. We assessed PDGFRA gain in 342 low-grade diffuse gliomas by quantitative polymerase chain reaction. Gain in PDGFRA was detected in 27 (16.3%) of 166 diffuse astrocytomas, significantly more frequent than in oligodendrogliomas (3 [2.6%] of 115, p < 0.0001). Analyses using previously published data from our laboratory showed an inverse correlation between PDGFRA gain and IDH1/2 mutations (p = 0.018) or 1p/19q loss (p < 0.0001). The vast majority of diffuse astrocytomas showed IDH1/2 mutations and/or PDGFRA gain (154 [93%] of 166). Mean survival of diffuse astrocytoma patients with PDGFRA gain was 8.8 ± 1.6 years, similar to that with IDH1/2 mutations (7.8 ± 0.5 years) or TP53 mutations (7.6 ± 0.6 years) but significantly longer than those with MET gain (4.4 ± 0.7 years). Dual-color fluorescence in situ hybridization in 6 diffuse astrocytomas with PDGFRA/MET co-gain identified by quantitative polymerase chain reaction revealed that PDGFRA and MET were typically amplified in different tumor cell populations. Tumor cells with coamplification were also focally observed, suggesting intratumoral heterogeneity, even in diffuse astrocytomas.

  13. Additive Manufacturing for Affordable Rocket Engines

    NASA Technical Reports Server (NTRS)

    West, Brian; Robertson, Elizabeth; Osborne, Robin; Calvert, Marty

    2016-01-01

    Additive manufacturing (also known as 3D printing) technology has the potential to drastically reduce costs and lead times associated with the development of complex liquid rocket engine systems. NASA is using 3D printing to manufacture rocket engine components including augmented spark igniters, injectors, turbopumps, and valves. NASA is advancing the process to certify these components for flight. Success Story: MSFC has been developing rocket 3D-printing technology using the Selective Laser Melting (SLM) process. Over the last several years, NASA has built and tested several injectors and combustion chambers. Recently, MSFC has 3D printed an augmented spark igniter for potential use the RS-25 engines that will be used on the Space Launch System. The new design is expected to reduce the cost of the igniter by a factor of four. MSFC has also 3D printed and tested a liquid hydrogen turbopump for potential use on an Upper Stage Engine. Additive manufacturing of the turbopump resulted in a 45% part count reduction. To understanding how the 3D printed parts perform and to certify them for flight, MSFC built a breadboard liquid rocket engine using additive manufactured components including injectors, turbomachinery, and valves. The liquid rocket engine was tested seven times in 2016 using liquid oxygen and liquid hydrogen. In addition to exposing the hardware to harsh environments, engineers learned to design for the new manufacturing technique, taking advantage of its capabilities and gaining awareness of its limitations. Benefit: The 3D-printing technology promises reduced cost and schedule for rocket engines. Cost is a function of complexity, and the most complicated features provide the largest opportunities for cost reductions. This is especially true where brazes or welds can be eliminated. The drastic reduction in part count achievable with 3D printing creates a waterfall effect that reduces the number of processes and drawings, decreases the amount of touch

  14. How Common Is Parallel Intron Gain? Rapid Evolution Versus Independent Creation in Recently Created Introns in Daphnia.

    PubMed

    Roy, Scott William

    2016-08-01

    The evolutionary history of the spliceosomal introns that interrupt nuclear genes in eukaryotes has been debated for four decades. Positions of introns show a high degree of coincidence between various eukaryotes, implying either than many modern introns are very old and/or that intron creation is highly biased toward certain sites, leading to rampant parallel intron gain. A series of articles in this and other journals reported evidence for a strikingly high degree of parallel insertion of introns in different alleles of the water flea Daphnia pulex Here, I report several new analyses of these data. Among the 23 loci reported to be undergoing parallel intron gain, I find that in five cases introns reported to be unrelated show extended sequence similarity strongly suggesting that the introns are in fact homologous. Five additional cases show extended conserved motifs between allegedly unrelated introns. For nearly all loci including the 13 remaining loci, at least one intron shows hallmarks of rapid sequence evolution, thwarting confident inference about homology. In addition, I reanalyze gene trees reconstructed from flanking exonic sequences, claimed by the original authors as additional evidence for parallel gain. I show that these phylogenetic trees frequently fail to recover expected relationships, and in any case show relationships not consistent with parallel intron gains. In total, I conclude that the data do not support widespread parallel intron gain in D. pulex These findings strengthen the notion that shared intron positions generally reflect ancestral introns, and thus the notion of complex genes in early eukaryotes.

  15. Gain and loss of elongation factor genes in green algae

    PubMed Central

    Cocquyt, Ellen; Verbruggen, Heroen; Leliaert, Frederik; Zechman, Frederick W; Sabbe, Koen; De Clerck, Olivier

    2009-01-01

    Background Two key genes of the translational apparatus, elongation factor-1 alpha (EF-1α) and elongation factor-like (EFL) have an almost mutually exclusive distribution in eukaryotes. In the green plant lineage, the Chlorophyta encode EFL except Acetabularia where EF-1α is found, and the Streptophyta possess EF-1α except Mesostigma, which has EFL. These results raise questions about evolutionary patterns of gain and loss of EF-1α and EFL. A previous study launched the hypothesis that EF-1α was the primitive state and that EFL was gained once in the ancestor of the green plants, followed by differential loss of EF-1α or EFL in the principal clades of the Viridiplantae. In order to gain more insight in the distribution of EF-1α and EFL in green plants and test this hypothesis we screened the presence of the genes in a large sample of green algae and analyzed their gain-loss dynamics in a maximum likelihood framework using continuous-time Markov models. Results Within the Chlorophyta, EF-1α is shown to be present in three ulvophycean orders (i.e., Dasycladales, Bryopsidales, Siphonocladales) and the genus Ignatius. Models describing gene gain-loss dynamics revealed that the presence of EF-1α, EFL or both genes along the backbone of the green plant phylogeny is highly uncertain due to sensitivity to branch lengths and lack of prior knowledge about ancestral states or rates of gene gain and loss. Model refinements based on insights gained from the EF-1α phylogeny reduce uncertainty but still imply several equally likely possibilities: a primitive EF-1α state with multiple independent EFL gains or coexistence of both genes in the ancestor of the Viridiplantae or Chlorophyta followed by differential loss of one or the other gene in the various lineages. Conclusion EF-1α is much more common among green algae than previously thought. The mutually exclusive distribution of EF-1α and EFL is confirmed in a large sample of green plants. Hypotheses about the gain

  16. Interventions for preventing excessive weight gain during pregnancy

    PubMed Central

    Muktabhant, Benja; Lumbiganon, Pisake; Ngamjarus, Chetta; Dowswell, Therese

    2014-01-01

    Background Excessive weight gain during pregnancy is associated with multiple maternal and neonatal complications. However, interventions to prevent excessive weight gain during pregnancy have not been adequately evaluated. Objectives To evaluate the effectiveness of interventions for preventing excessive weight gain during pregnancy and associated pregnancy complications. Search methods We searched the Cochrane Pregnancy and Childbirth Group’s Trials Register (20 October 2011) and MEDLINE (1966 to 20 October 2011). Selection criteria All randomised controlled trials and quasi-randomised trials of interventions for preventing excessive weight gain during pregnancy. Data collection and analysis We assessed for inclusion all potential studies we identified as a result of the search strategy. At least two review authors independently assessed trial quality and extracted data. We resolved discrepancies through discussion. We have presented results using risk ratio (RR) for categorical data and mean difference for continuous data. We analysed data using a fixed-effect model. Main results We included 28 studies involving 3976 women; 27 of these studies with 3964 women contributed data to the analyses. Interventions focused on a broad range of interventions. However, for most outcomes we could not combine data in a meta-analysis, and where we did pool data, no more than two or three studies could be combined for a particular intervention and outcome. Overall, results from this review were mainly not statistically significant, and where there did appear to be differences between intervention and control groups, results were not consistent. For women in general clinic populations one (behavioural counselling versus standard care) of three interventions examined was associated with a reduction in the rate of excessive weight gain (RR 0.72, 95% confidence interval 0.54 to 0.95); for women in high-risk groups no intervention appeared to reduce excess weight gain. There were

  17. Neural Net Gains Estimation Based on an Equivalent Model.

    PubMed

    Aguilar Cruz, Karen Alicia; Medel Juárez, José de Jesús; Fernández Muñoz, José Luis; Esmeralda Vigueras Velázquez, Midory

    2016-01-01

    A model of an Equivalent Artificial Neural Net (EANN) describes the gains set, viewed as parameters in a layer, and this consideration is a reproducible process, applicable to a neuron in a neural net (NN). The EANN helps to estimate the NN gains or parameters, so we propose two methods to determine them. The first considers a fuzzy inference combined with the traditional Kalman filter, obtaining the equivalent model and estimating in a fuzzy sense the gains matrix A and the proper gain K into the traditional filter identification. The second develops a direct estimation in state space, describing an EANN using the expected value and the recursive description of the gains estimation. Finally, a comparison of both descriptions is performed; highlighting the analytical method describes the neural net coefficients in a direct form, whereas the other technique requires selecting into the Knowledge Base (KB) the factors based on the functional error and the reference signal built with the past information of the system.

  18. Hitchhiking selection is driving intron gain in a pathogenic fungus.

    PubMed

    Brunner, Patrick C; Torriani, Stefano F F; Croll, Daniel; Stukenbrock, Eva H; McDonald, Bruce A

    2014-07-01

    The variability of intron density among eukaryotes is puzzling and still debated. Most previous studies have been limited because of the near absence of intron presence-absence polymorphism (IPAP) within species or because comparisons could be made only between distantly related species. We conducted population genetic analyses on eight loci showing IPAP to investigate the effect of natural selection on intron dynamics in a global collection of the panmictic fungal plant pathogen Zymoseptoria tritici and its very close relatives. Five of these loci likely represent recent intron gains because their absence is fixed among the closest relatives of Z. tritici, and three likely represent recent intron losses because their presence is fixed among the close relatives. We analyzed signatures of selection by comparing allele frequencies, nucleotide diversities, and rates of recombination and found compelling evidence that at least two out of the five intron-gain loci, a SWIM zinc-finger gene and a sugar transporter, are under directional selection favoring alleles that gained the intron. Our results suggest that the intron-present alleles of these loci are sweeping to fixation, providing a genetic hitchhiking mechanism to explain rapid intron gain in Z. tritici. The overall findings are consistent with the hypothesis that intron gains are more likely to be driven by selection while intron losses are more likely to be due to neutral processes such as genetic drift.

  19. Preventing weight gain in adults: the pound of prevention study.

    PubMed Central

    Jeffery, R W; French, S A

    1999-01-01

    OBJECTIVES: This study examined whether weight gain with age could be prevented through the use of a low-intensity intervention. METHODS: Participants, 228 men and 998 women recruited from diverse sources, were randomized to one of the following groups: (1) no-contact control, (2) education through monthly newsletters, or (3) education plus incentives for participation. All participants were weighed and completed questionnaires about behaviors and attitudes related to weight at baseline and annually for 3 years thereafter. RESULTS: Individuals in intervention groups reported favorable changes over time in frequency of weighting and healthy dieting practices relative to those in the control group. These behavior changes were in turn related to a reduced rate of weight gain over time. However, weight gain over 3 years did not differ significantly by treatment group. CONCLUSIONS: This low-intensity educational approach to weight gain prevention sustained interest over a lengthy time period and was associated positively with behavior change, but it was not strong enough to significantly reduce weight gain with age. PMID:10224988

  20. Neural Net Gains Estimation Based on an Equivalent Model.

    PubMed

    Aguilar Cruz, Karen Alicia; Medel Juárez, José de Jesús; Fernández Muñoz, José Luis; Esmeralda Vigueras Velázquez, Midory

    2016-01-01

    A model of an Equivalent Artificial Neural Net (EANN) describes the gains set, viewed as parameters in a layer, and this consideration is a reproducible process, applicable to a neuron in a neural net (NN). The EANN helps to estimate the NN gains or parameters, so we propose two methods to determine them. The first considers a fuzzy inference combined with the traditional Kalman filter, obtaining the equivalent model and estimating in a fuzzy sense the gains matrix A and the proper gain K into the traditional filter identification. The second develops a direct estimation in state space, describing an EANN using the expected value and the recursive description of the gains estimation. Finally, a comparison of both descriptions is performed; highlighting the analytical method describes the neural net coefficients in a direct form, whereas the other technique requires selecting into the Knowledge Base (KB) the factors based on the functional error and the reference signal built with the past information of the system. PMID:27366146

  1. Neural Net Gains Estimation Based on an Equivalent Model

    PubMed Central

    Aguilar Cruz, Karen Alicia; Medel Juárez, José de Jesús; Fernández Muñoz, José Luis; Esmeralda Vigueras Velázquez, Midory

    2016-01-01

    A model of an Equivalent Artificial Neural Net (EANN) describes the gains set, viewed as parameters in a layer, and this consideration is a reproducible process, applicable to a neuron in a neural net (NN). The EANN helps to estimate the NN gains or parameters, so we propose two methods to determine them. The first considers a fuzzy inference combined with the traditional Kalman filter, obtaining the equivalent model and estimating in a fuzzy sense the gains matrix A and the proper gain K into the traditional filter identification. The second develops a direct estimation in state space, describing an EANN using the expected value and the recursive description of the gains estimation. Finally, a comparison of both descriptions is performed; highlighting the analytical method describes the neural net coefficients in a direct form, whereas the other technique requires selecting into the Knowledge Base (KB) the factors based on the functional error and the reference signal built with the past information of the system. PMID:27366146

  2. Dieting and restrained eating as prospective predictors of weight gain.

    PubMed

    Lowe, Michael R; Doshi, Sapna D; Katterman, Shawn N; Feig, Emily H

    2013-09-02

    Research in normal weight individuals paradoxically suggests that measures of attempted eating restriction might represent robust predictors of weight gain. This review examined the extent to which measures of dieting (e.g., self-reported weight loss dieting in the past year) and dietary restraint (e.g., the Cognitive Restraint scale from the Three-Factor Eating Questionnaire) have prospectively predicted weight change. We located and reviewed 25 prospective studies containing 40 relevant comparisons. Studies were limited to those in which participants were non-obese (with a mean BMI between 18.5 and 30) and averaged at least 12 years old. Neither measure predicted future weight loss. Fifteen of the 20 comparisons (75%) that examined measures of dieting significantly predicted future weight gain whereas only 1 of 20 (5%) that examined restrained eating measures did so. Two plausible explanations for these findings are that: (1) dieters and restrained eaters do not differ in terms of an underlying proneness toward weight gain, but restrained eating represents a more effective means of preventing it; and (2) normal weight individuals who diet do so because they are resisting a powerful predisposition toward weight gain which dieting ultimately fails to prevent. Recent dieting in non-obese individuals may be a valuable proxy of susceptibility to weight gain. This easily assessed characteristic could identify individuals for whom obesity prevention interventions would be particularly appropriate.

  3. Enantioselective Michael Addition of Water

    PubMed Central

    Chen, Bi-Shuang; Resch, Verena; Otten, Linda G; Hanefeld, Ulf

    2015-01-01

    The enantioselective Michael addition using water as both nucleophile and solvent has to date proved beyond the ability of synthetic chemists. Herein, the direct, enantioselective Michael addition of water in water to prepare important β-hydroxy carbonyl compounds using whole cells of Rhodococcus strains is described. Good yields and excellent enantioselectivities were achieved with this method. Deuterium labeling studies demonstrate that a Michael hydratase catalyzes the water addition exclusively with anti-stereochemistry. PMID:25529526

  4. Enantioselective Michael addition of water.

    PubMed

    Chen, Bi-Shuang; Resch, Verena; Otten, Linda G; Hanefeld, Ulf

    2015-02-01

    The enantioselective Michael addition using water as both nucleophile and solvent has to date proved beyond the ability of synthetic chemists. Herein, the direct, enantioselective Michael addition of water in water to prepare important β-hydroxy carbonyl compounds using whole cells of Rhodococcus strains is described. Good yields and excellent enantioselectivities were achieved with this method. Deuterium labeling studies demonstrate that a Michael hydratase catalyzes the water addition exclusively with anti-stereochemistry.

  5. A prospective study of weight gain associated with chronotype among college freshmen.

    PubMed

    Culnan, Elizabeth; Kloss, Jacqueline D; Grandner, Michael

    2013-06-01

    A prospective study of chronotype as a predictor of increased weight gain and body mass index (BMI) among college freshman was undertaken. At baseline, 137 college freshmen were characterized as morning, neutral, or evening types using the reduced version of the Morningness-Eveningness Questionnaire. Additionally, information was collected regarding weight, BMI, and health habits (e.g., junk food and alcohol consumption). These additional measures consisted of a descriptive questionnaire, the Pittsburgh Sleep Quality Index, the International Physical Activity Questionnaire, the Gray-Donald Eating Patterns Questionnaire, and the Positive and Negative Affect Scale. Participants included 79 females and 80 males with a mean age of 18.25 (SD = 0.56) yrs. Eight weeks later, participants returned (N = 54) to complete follow-up measures, which were identical to baseline assessments with the exception of the descriptive questionnaire, in which demographic questions were removed. Evening types had a significantly greater BMI gain (p < 0.05) when compared with morning/neutral types. Health behaviors did not differ by chronotype. Future studies should seek to clarify the mechanisms underlying the chronotype-BMI/weight gain relationship.

  6. Quantum noise of a white-light cavity using a double-pumped gain medium

    NASA Astrophysics Data System (ADS)

    Ma, Yiqiu; Miao, Haixing; Zhao, Chunnong; Chen, Yanbei

    2015-08-01

    Laser interferometric gravitational-wave detectors implement Fabry-Pérot cavities to increase their peak sensitivity. However, this is at the cost of reducing their detection bandwidth, which originates from the propagation phase delay of the light. The "white-light-cavity" idea, first proposed by Wicht et al. [Opt. Commun. 34, 431 (1997), 10.1016/S0030-4018(96)00579-2], is to circumvent this limitation by introducing anomalous dispersion, using a double-pumped gain medium, to compensate for such a phase delay. In this article, starting from the Hamiltonian of the atom-light interaction, we apply an input-output formalism to evaluate the quantum noise of the system. We find that apart from the additional noise associated with the parametric amplification process noted by others, the stability condition for the entire system poses an additional constraint. By surveying the parameter regimes where the gain medium remains stable (not lasing) and stationary, we find that there is no net enhancement of the shot-noise-limited sensitivity. Therefore, other gain media or different parameter regimes should be explored for realizing the white-light cavity.

  7. Gasoline additives, emissions, and performance

    SciTech Connect

    1995-12-31

    The papers included in this publication deal with the influence of fuel, additive, and hardware changes on a variety of vehicle performance characteristics. Advanced techniques for measuring these performance parameters are also described. Contents include: Fleet test evaluation of gasoline additives for intake valve and combustion chamber deposit clean up; A technique for evaluating octane requirement additives in modern engines on dynamometer test stands; A fleet test of two additive technologies comparing their effects on tailpipe emissions; Investigation into the vehicle exhaust emissions of high percentage ethanol blends; Variability in hydrocarbon speciation measurements at low emission (ULEV) levels; and more.

  8. Trigeminal high-frequency stimulation produces short- and long-term modification of reflex blink gain

    PubMed Central

    Ryan, Michael; Kaminer, Jaime; Enmore, Patricia

    2013-01-01

    Reflex blinks provide a model system for investigating motor learning in normal and pathological states. We investigated whether high-frequency stimulation (HFS) of the supraorbital branch of the trigeminal nerve before the R2 blink component (HFS-B) decreases reflex blink gain in alert rats. As with humans (Mao JB, Evinger C. J Neurosci 21: RC151, 2001), HFS-B significantly reduced blink size in the first hour after treatment for rats. Repeated days of HFS-B treatment produced long-term depression of blink circuits. Blink gain decreased exponentially across days, indicating a long-term depression of blink circuits. Additionally, the HFS-B protocol became more effective at depressing blink amplitude across days of treatment. This depression was not habituation, because neither long- nor short-term blink changes occurred when HFS was presented after the R2. To investigate whether gain modifications produced by HFS-B involved cerebellar networks, we trained rats in a delay eyelid conditioning paradigm using HFS-B as the unconditioned stimulus and a tone as the conditioned stimulus. As HFS-B depresses blink circuits and delay conditioning enhances blink circuit activity, occlusion should occur if they share neural networks. Rats acquiring robust eyelid conditioning did not exhibit decreases in blink gain, whereas rats developing low levels of eyelid conditioning exhibited weak, short-term reductions in blink gain. These results suggested that delay eyelid conditioning and long-term HFS-B utilize some of the same cerebellar circuits. The ability of repeated HFS-B treatment to depress trigeminal blink circuit activity long term implied that it may be a useful protocol to reduce hyperexcitable blink circuits that underlie diseases like benign essential blepharospasm. PMID:24285868

  9. Profile of the Spleen Transcriptome in Beef Steers with Variation in Gain and Feed Intake.

    PubMed

    Lindholm-Perry, Amanda K; Kern, Rebecca J; Keel, Brittney N; Snelling, Warren M; Kuehn, Larry A; Freetly, Harvey C

    2016-01-01

    We have previously identified components of the immune system contributing to feed intake and gain in both the rumen and small intestine of beef steers. In this study, we examined the spleen, a major lymphatic organ near the digestive tract, to determine whether it was also influencing individual feed efficiency status through immune responses. Animals (n = 16) that were divergent for gain and intake were selected for tissue sampling. The spleen transcriptomes were evaluated by microarray. A total of 1216 genes were identified as differentially expressed. Genes were over-represented in Kyoto encyclopedia of genes and genomes (KEGG) pathways including biological regulation, protein folding, cell communication, immune systems process, response to stress, and RNA metabolic process. Several stress response or heat shock genes including HSPH1, HSPA1A, HSPA4, DNAJB4, DNAJA4, etc., were identified as a stress response functional gene cluster in the low gain-low intake animals. These genes were up-regulated amongst the low gain-low intake animals compared to all other groups. Canonical pathways associated with the differentially expressed genes included the coagulation system, extrinsic prothrombin activation, protein ubiquitination, unfolded protein response, and aldosterone signaling in epithelial cells. An analysis of expressed copy number variable (CNV) genes in the spleen produced some of the same genes and gene families that were differentially expressed. Our data suggests the splenic contribution to some of the underlying variation among gain and intake within this group of animals may be a result of immune function and stress response. In addition, some of the differences in immune response functions may be related to gene copy number. PMID:27504120

  10. Integrative analysis of 1q23.3 copy number gain in metastatic urothelial carcinoma

    PubMed Central

    Riester, Markus; Werner, Lillian; Bellmunt, Joaquim; Selvarajah, Shamini; Guancial, Elizabeth A.; Weir, Barbara A.; Stack, Edward C.; Park, Rachel S.; O’Brien, Robert; Schutz, Fabio A. B.; Choueiri, Toni K.; Signoretti, Sabina; Lloreta, Josep; Marchionni, Luigi; Gallardo, Enrique; Rojo, Federico; Garcia, Denise I.; Chekaluk, Yvonne; Kwiatkowski, David; Bochner, Bernard; Hahn, William C.; Ligon, Azra H.; Barletta, Justine A.; Loda, Massimo; Berman, David M.; Kantoff, Philip; Michor, Franziska; Rosenberg, Jonathan E.

    2014-01-01

    Purpose Metastatic urothelial carcinoma (UC) of the bladder is associated with multiple somatic copy number alterations (SCNAs). We evaluated SCNAs to identify predictors of poor survival in patients with metastatic UC treated with platinum-based chemotherapy. Experimental Design We obtained overall survival (OS) and array DNA copy number data from metastatic UC patients in two cohorts. Associations between recurrent SCNAs and OS were determined by a Cox proportional hazard model adjusting for performance status and visceral disease. mRNA expression was evaluated for potential candidate genes by Nanostring nCounter to identify transcripts from the region that are associated with copy number gain. In addition, expression data from an independent cohort was used to identify candidate genes. Results Multiple areas of recurrent significant gains and losses were identified. Gain of 1q23.3 was independently associated with a shortened OS in the both cohorts (adjusted HR 2.96; 95% CI, 1.35 to 6.48; P = 0.01 and adjusted HR 5.03; 95% CI 1.43-17.73; P < 0.001). The F11R, PFDN2, PPOX, USP21 and DEDD genes, all located on 1q23.3, were closely associated with poor outcome. Conclusions 1q23.3 copy number gain displayed association with poor survival in two cohorts of metastatic UC. The identification of the target of this copy number gain is ongoing, and exploration of this finding in other disease states may be useful for the early identification of poor risk UC patients. Prospective validation of the survival association is necessary to demonstrate clinical relevance. PMID:24486590

  11. Profile of the Spleen Transcriptome in Beef Steers with Variation in Gain and Feed Intake

    PubMed Central

    Lindholm-Perry, Amanda K.; Kern, Rebecca J.; Keel, Brittney N.; Snelling, Warren M.; Kuehn, Larry A.; Freetly, Harvey C.

    2016-01-01

    We have previously identified components of the immune system contributing to feed intake and gain in both the rumen and small intestine of beef steers. In this study, we examined the spleen, a major lymphatic organ near the digestive tract, to determine whether it was also influencing individual feed efficiency status through immune responses. Animals (n = 16) that were divergent for gain and intake were selected for tissue sampling. The spleen transcriptomes were evaluated by microarray. A total of 1216 genes were identified as differentially expressed. Genes were over-represented in Kyoto encyclopedia of genes and genomes (KEGG) pathways including biological regulation, protein folding, cell communication, immune systems process, response to stress, and RNA metabolic process. Several stress response or heat shock genes including HSPH1, HSPA1A, HSPA4, DNAJB4, DNAJA4, etc., were identified as a stress response functional gene cluster in the low gain-low intake animals. These genes were up-regulated amongst the low gain-low intake animals compared to all other groups. Canonical pathways associated with the differentially expressed genes included the coagulation system, extrinsic prothrombin activation, protein ubiquitination, unfolded protein response, and aldosterone signaling in epithelial cells. An analysis of expressed copy number variable (CNV) genes in the spleen produced some of the same genes and gene families that were differentially expressed. Our data suggests the splenic contribution to some of the underlying variation among gain and intake within this group of animals may be a result of immune function and stress response. In addition, some of the differences in immune response functions may be related to gene copy number. PMID:27504120

  12. High-Gain High-Field Fusion Plasma.

    PubMed

    Li, Ge

    2015-01-01

    A Faraday wheel (FW)-an electric generator of constant electrical polarity that produces huge currents-could be implemented in an existing tokamak to study high-gain high-field (HGHF) fusion plasma, such as the Experimental Advanced Superconducting Tokamak (EAST). HGHF plasma can be realized in EAST by updating its pulsed-power system to compress plasma in two steps by induction fields; high gains of the Lawson trinity parameter and fusion power are both predicted by formulating the HGHF plasma. Both gain rates are faster than the decrease rate of the plasma volume. The formulation is checked by earlier ATC tests. Good agreement between theory and tests indicates that scaling to over 10 T at EAST may be possible by two-step compressions with a compression ratio of the minor radius of up to 3. These results point to a quick new path of fusion plasma study, i.e., simulating the Sun by EAST. PMID:26507314

  13. Note: Non-gain microchannel plate gated framing camera

    SciTech Connect

    Cai Houzhi; Peng Xiang; Liu Jinyuan; Niu Lihong; Peng Wenda; Niu Hanben; Long Jinghua

    2011-05-15

    An x-ray framing camera using a non-gain microchannel plate (MCP) is reported in this article. The advantage of the non-gain MCP is the less transit time spread. The non-gain MCP gated framing camera has four microstrip line cathodes with 6 mm in width. The time domain reflectometry curves of the four microstrip lines are measured, which show that the characteristic impedance of each microstrip line is about 17 {Omega}. While the photocathode is driven by the gating electrical pulse with width of 125 ps and amplitude of -1.48 kV with -400 V bias, the measured exposure time of this camera is about 72 ps.

  14. Memristive devices as parameter setting elements in programmable gain amplifiers

    NASA Astrophysics Data System (ADS)

    Berdan, R.; Prodromakis, T.; Salaoru, I.; Khiat, A.; Toumazou, C.

    2012-12-01

    In this paper, we investigate the AC performance of a variable gain amplifier that utilizes an in-house manufactured memristor as a gain setting element. Analysis includes frequency and phase responses as the memristor is programmed at different resistive states. A TiO2-based solid-state memristor was employed in the feedback branch of an inverting voltage amplifier and was programmed externally. We have also observed indications of memcapacitive effects and a correlation with resistive states is presented. We demonstrate that our TiO2 memristive devices, although possessing relatively low ROFF/RON switching ratios (˜10), are versatile and can be used reliably in programmable gain amplifiers.

  15. A Temperature-Based Gain Calibration Technique for Precision Radiometry

    NASA Astrophysics Data System (ADS)

    Parashare, Chaitali Ravindra

    Detecting extremely weak signals in radio astronomy demands high sensitivity and stability of the receivers. The gain of a typical radio astronomy receiver is extremely large, and therefore, even very small gain instabilities can dominate the received noise power and degrade the instrument sensitivity. Hence, receiver stabilization is of prime importance. Gain variations occur mainly due to ambient temperature fluctuations. We take a new approach to receiver stabilization, which makes use of active temperature monitoring and corrects for the gain fluctuations in post processing. This approach is purely passive and does not include noise injection or switching for calibration. This system is to be used for the Precision Array for Probing the Epoch of Reionization (PAPER), which is being developed to detect the extremely faint neutral hydrogen (HI) signature of the Epoch of Reionization (EoR). The epoch of reionization refers to the period in the history of the Universe when the first stars and galaxies started to form. When there are N antenna elements in the case of a large scale array, all elements may not be subjected to the same environmental conditions at a given time. Hence, we expect to mitigate the gain variations by monitoring the physical temperature of each element of the array. This stabilization approach will also benefit experiments like EDGES (Experiment to Detect the Global EoR Signature) and DARE (Dark Ages Radio Explorer), which involve a direct measurement of the global 21 cm signal using a single antenna element and hence, require an extremely stable system. This dissertation focuses on the development and evaluation of a calibration technique that compensates for the gain variations caused due to temperature fluctuations of the RF components. It carefully examines the temperature dependence of the components in the receiver chain. The results from the first-order field instrument, called a Gainometer (GoM), highlight the issue with the cable

  16. Bragg-selectivity of a volume gain grating

    NASA Astrophysics Data System (ADS)

    Damzen, M. J.; Matsumoto, Y.; Crofts, G. J.; Green, R. P. M.

    1996-02-01

    We adapt the theory of volume grating holography to model analytically the diffraction efficiency of a volume gain grating and its variation due to deviation from Bragg-matching. We present modelling of the case when the gain grating is optically-written in a saturable laser amplifier by spatial hole burning, under both steady-state and transient conditions. We perform an experimental measurement of the angular-sensitivity of a volume transmission gain grating optically-written in a Nd:YAG amplifier rod. It is shown that the amplification of the writing beams needs to be considered since this leads to a spatial variation of the grating modulation depth and thereby to the reduction of its angular sensitivity compared to the uniform grating case.

  17. Gain spectrum in gated x-ray MCPs

    SciTech Connect

    Kyrala, George A; Oertel, John A; Archuleta, Thomas N; Holder, Joe

    2009-01-01

    The gain spectrum in a gated multichannel intensifier output depends on the gain and spatial averaging. The spectrum affects the minimum signal that can be detected as well as the signal to noise in the detected images. We will present data on the gain-spectrum for the GXD detector, a gated x-ray detector to be used at the National Ignition Facility. The data was recorded on a cooled CCD detector, with an x-ray gating time of approximately 75 ps, selected from a range of 0.2 and 1 ns electrical pulse width determined by pulse forming modules were also used. The detector was characterized at the TRIDENT laser facility, using a 2.4 ns long x-ray at 4.75 keV. The x-rays were generated by the interaction of the focused Trident laser beam with a Titanium target.

  18. Information Gain Based Dimensionality Selection for Classifying Text Documents

    SciTech Connect

    Dumidu Wijayasekara; Milos Manic; Miles McQueen

    2013-06-01

    Selecting the optimal dimensions for various knowledge extraction applications is an essential component of data mining. Dimensionality selection techniques are utilized in classification applications to increase the classification accuracy and reduce the computational complexity. In text classification, where the dimensionality of the dataset is extremely high, dimensionality selection is even more important. This paper presents a novel, genetic algorithm based methodology, for dimensionality selection in text mining applications that utilizes information gain. The presented methodology uses information gain of each dimension to change the mutation probability of chromosomes dynamically. Since the information gain is calculated a priori, the computational complexity is not affected. The presented method was tested on a specific text classification problem and compared with conventional genetic algorithm based dimensionality selection. The results show an improvement of 3% in the true positives and 1.6% in the true negatives over conventional dimensionality selection methods.

  19. High-Gain High-Field Fusion Plasma

    NASA Astrophysics Data System (ADS)

    Li, Ge

    2015-10-01

    A Faraday wheel (FW)—an electric generator of constant electrical polarity that produces huge currents—could be implemented in an existing tokamak to study high-gain high-field (HGHF) fusion plasma, such as the Experimental Advanced Superconducting Tokamak (EAST). HGHF plasma can be realized in EAST by updating its pulsed-power system to compress plasma in two steps by induction fields; high gains of the Lawson trinity parameter and fusion power are both predicted by formulating the HGHF plasma. Both gain rates are faster than the decrease rate of the plasma volume. The formulation is checked by earlier ATC tests. Good agreement between theory and tests indicates that scaling to over 10 T at EAST may be possible by two-step compressions with a compression ratio of the minor radius of up to 3. These results point to a quick new path of fusion plasma study, i.e., simulating the Sun by EAST.

  20. Ethereal and material gain: unanticipated opportunity with illness or disability.

    PubMed

    O'Mahony, Seamus; Shanahan, Fergus

    2014-02-01

    When caregivers address the positive aspects of illness or disability, there is a risk of patronising the sufferer. It is equally problematic when secondary gain is judged in a negative light and impedes an effective doctor-patient relationship. Changing attitudes, and particularly the negative perception of a patient's gain from illness, are reflected in biographies of artists, philosophers and other creative individuals. In contrast, some memoirs about illness feature a retrospective discussion of the positive features of the experience - from one who is now free from the ordeal. The experience of continual sufferers may be more instructive. We examine contemporary examples of unanticipated advantage or gain arising from ongoing disability or illness. The contribution of disability/illness to remarkable achievement promotes enhanced self-appreciation for patients and may foster in others a better understanding of what it means to suffer and live with disability. PMID:24532744

  1. Note: Non-gain microchannel plate gated framing camera.

    PubMed

    Cai, Houzhi; Liu, Jinyuan; Peng, Xiang; Niu, Lihong; Peng, Wenda; Niu, Hanben; Long, Jinghua

    2011-05-01

    An x-ray framing camera using a non-gain microchannel plate (MCP) is reported in this article. The advantage of the non-gain MCP is the less transit time spread. The non-gain MCP gated framing camera has four microstrip line cathodes with 6 mm in width. The time domain reflectometry curves of the four microstrip lines are measured, which show that the characteristic impedance of each microstrip line is about 17 Ω. While the photocathode is driven by the gating electrical pulse with width of 125 ps and amplitude of -1.48 kV with -400 V bias, the measured exposure time of this camera is about 72 ps.

  2. Computing with phase locked loops: choosing gains and delays.

    PubMed

    Piqueira, J C; Orsatti, F M; Monteiro, L A

    2003-01-01

    We simulate a four-node fully connected phase-locked loop (PLL) network with an architecture similar to the neural network proposed by Hoppensteadt and Izhikevich (1999, 2000), using second-order PLLs. The idea is to complement their work analyzing some engineering questions like:how the individual gain of the nodes affects the synchronous state of whole network; how the individual gain of the nodes affects the acquisition time of the whole network; how close the free-running frequencies of the nodes need to be in order to the network be able to acquire the synchronous state; how the delays between nodes affect the synchronous state frequency. The computational results show that the Hoppensteadt-Izhikevich network is robust to the variation of these parameters and their effects are described through graphics showing the dependence of the synchronous state frequency and acquisition time with gains, free-running frequencies, and delays.

  3. Characteristics of current filamentation in high gain photoconductive semiconductor switching

    SciTech Connect

    Zutavern, F J; Loubriel, G M; O'Malley, M W; Helgeson, W D; McLaughlin, D L; Denison, G J

    1992-01-01

    Characteristics of current filamentation are reported for high gain photoconductive semiconductor switches (PCSS). Infrared photoluminescence is used to monitor carrier recombination radiation during fast initiation of high gain switching in large (1.5 cm gap) lateral GaAs PCSS. Spatial modulation of the optical trigger, a 200--300 ps pulse width laser, is examined. Effects on the location and number of current filaments, rise time, and delay to high gain switching, minimum trigger energy, and degradation of switch contacts are presented. Implications of these measurements for the theoretical understanding and practical development of these switches are discussed. Efforts to increase current density and reduce switch size and optical trigger energy requirements are described. Results from contact development and device lifetime testing are presented and the impact of these results on practical device applications is discussed.

  4. Optofluidic lasers with a single molecular layer of gain.

    PubMed

    Chen, Qiushu; Ritt, Michael; Sivaramakrishnan, Sivaraj; Sun, Yuze; Fan, Xudong

    2014-12-21

    We achieve optofluidic lasers with a single molecular layer of gain, in which green fluorescent protein, dye-labeled bovine serum albumin, and dye-labeled DNA, are used as the gain medium and attached to the surface of a ring resonator via surface immobilization biochemical methods. It is estimated that the surface density of the gain molecules is on the order of 10(12) cm(-2), sufficient for lasing under pulsed optical excitation. It is further shown that the optofluidic laser can be tuned by energy transfer mechanisms through biomolecular interactions. This work not only opens a door to novel photonic devices that can be controlled at the level of a single molecular layer but also provides a promising sensing platform to analyze biochemical processes at the solid-liquid interface.

  5. Optimal Sample Complexity for Blind Gain and Phase Calibration

    NASA Astrophysics Data System (ADS)

    Li, Yanjun; Lee, Kiryung; Bresler, Yoram

    2016-11-01

    Blind gain and phase calibration (BGPC) is a structured bilinear inverse problem, which arises in many applications, including inverse rendering in computational relighting (albedo estimation with unknown lighting), blind phase and gain calibration in sensor array processing, and multichannel blind deconvolution. The fundamental question of the uniqueness of the solutions to such problems has been addressed only recently. In a previous paper, we proposed studying the identifiability in bilinear inverse problems up to transformation groups. In particular, we studied several special cases of blind gain and phase calibration, including the cases of subspace and joint sparsity models on the signals, and gave sufficient and necessary conditions for identifiability up to certain transformation groups. However, there were gaps between the sample complexities in the sufficient conditions and the necessary conditions. In this paper, under a mild assumption that the signals and models are generic, we bridge the gaps by deriving tight sufficient conditions with optimal sample complexities.

  6. Note: Non-gain microchannel plate gated framing camera.

    PubMed

    Cai, Houzhi; Liu, Jinyuan; Peng, Xiang; Niu, Lihong; Peng, Wenda; Niu, Hanben; Long, Jinghua

    2011-05-01

    An x-ray framing camera using a non-gain microchannel plate (MCP) is reported in this article. The advantage of the non-gain MCP is the less transit time spread. The non-gain MCP gated framing camera has four microstrip line cathodes with 6 mm in width. The time domain reflectometry curves of the four microstrip lines are measured, which show that the characteristic impedance of each microstrip line is about 17 Ω. While the photocathode is driven by the gating electrical pulse with width of 125 ps and amplitude of -1.48 kV with -400 V bias, the measured exposure time of this camera is about 72 ps. PMID:21639550

  7. Potential impact of contrails on solar energy gain

    NASA Astrophysics Data System (ADS)

    Weihs, P.; Rennhofer, M.; Baumgartner, D.; Gadermaier, J.; Wagner, J.; Laube, W.

    2014-08-01

    We investigated the effect of contrails on global shortwave radiation and on solar energy gain. The study was done for days with a high contrail persistence and looking at situations where the contrails were obstructing the sun. Measurements of cloudiness using a fish eye camera, diffuse and direct shortwave measurements and measurements of the short circuit current of three different types of photovoltaic (PV) modules were performed at the solar observatory Kanzelhöhe (1540 m a.s.l.) during a period of one year with a time resolution of one minute. Our results show that contrails moving between sun and observer/sensor may reduce the global radiation by up to 72%. A statistic of contrail persistence and influence of contrails on global irradiance and solar energy gain is presented. The losses in solar energy gain that were recorded may even be critical under some circumstances for PV system performance.

  8. Potential impact of contrails on solar energy gain

    NASA Astrophysics Data System (ADS)

    Weihs, P.; Rennhofer, M.; Baumgartner, D. J.; Gadermaier, J.; Wagner, J. E.; Gehring, J. E.; Laube, W.

    2015-03-01

    The effect of contrails on global short-wave radiation (sum of direct and downward diffuse solar radiation) and on solar energy gain was investigated. The study was performed during days with high contrail persistence and focused on situations where the contrails were obstructing the sun. Measurements of cloudiness using a fish-eye camera, diffuse and direct short-wave measurements and measurements of the short circuit current of three different types of photovoltaic (PV) modules were performed at the Kanzelhöhe Observatory (1540 m a.s.l.) with a time resolution of 1 min over a period of 1 year. The results show that contrails moving between sun and observer/sensor may reduce the global radiation by up to 72%. An analysis of contrail persistence and the influence of contrails on global irradiance and solar energy gain is presented. The losses in solar energy gain that were recorded may be critical under specific circumstances.

  9. Method for passively compensating for temperature coefficient of gain in silicon photomultipliers and similar devices

    DOEpatents

    McKisson, John E.; Barbosa, Fernando

    2015-09-01

    A method for designing a completely passive bias compensation circuit to stabilize the gain of multiple pixel avalanche photo detector devices. The method includes determining circuitry design and component values to achieve a desired precision of gain stability. The method can be used with any temperature sensitive device with a nominally linear coefficient of voltage dependent parameter that must be stabilized. The circuitry design includes a negative temperature coefficient resistor in thermal contact with the photomultiplier device to provide a varying resistance and a second fixed resistor to form a voltage divider that can be chosen to set the desired slope and intercept for the characteristic with a specific voltage source value. The addition of a third resistor to the divider network provides a solution set for a set of SiPM devices that requires only a single stabilized voltage source value.

  10. Surface waves at the interface with an antisymmetric gain/loss profile

    SciTech Connect

    Ctyroky, Jiri; Kuzmiak, Vladimir; Eyderman, Sergey

    2010-10-07

    We studied properties of strongly guiding two-mode waveguides with antisymmetric gain/loss profile which constitute photonic analogues of quantum mechanical structures with parity-time symmetry breaking. For both TE and TM polarizations, the dependences of effective indices of the guided modes vs. gain/loss coefficient exhibit a degenerate critical point that defines two regimes with profoundly different behavior. In addition, we have shown that the interface between the two media supports propagation of a strongly confined non-attenuated TM polarized surface wave. We examined the properties of the surface wave obtained by both the modal and FDTD method and discuss the differences between the results obtained by both techniques as both the material and geometrical parameters are varied.

  11. A bootstrapped, low-noise, and high-gain photodetector for shot noise measurement.

    PubMed

    Zhou, Haijun; Yang, Wenhai; Li, Zhixiu; Li, Xuefeng; Zheng, Yaohui

    2014-01-01

    We presented a low-noise, high-gain photodetector based on the bootstrap structure and the L-C (inductance and capacitance) combination. Electronic characteristics of the photodetector, including electronic noise, gain and frequency response, and dynamic range, were verified through a single-frequency Nd:YVO4 laser at 1064 nm with coherent output. The measured shot noise of 50 μW laser was 13 dB above the electronic noise at the analysis frequency of 2 MHz, and 10 dB at 3 MHz. And a maximum clearance of 28 dB at 2 MHz was achieved when 1.52 mW laser was illuminated. In addition, the photodetector showed excellent linearities for both DC and AC amplifications in the laser power range between 12.5 μW and 1.52 mW.

  12. A bootstrapped, low-noise, and high-gain photodetector for shot noise measurement

    SciTech Connect

    Zhou, Haijun; Yang, Wenhai; Li, Zhixiu; Li, Xuefeng; Zheng, Yaohui

    2014-01-15

    We presented a low-noise, high-gain photodetector based on the bootstrap structure and the L-C (inductance and capacitance) combination. Electronic characteristics of the photodetector, including electronic noise, gain and frequency response, and dynamic range, were verified through a single-frequency Nd:YVO{sub 4} laser at 1064 nm with coherent output. The measured shot noise of 50 μW laser was 13 dB above the electronic noise at the analysis frequency of 2 MHz, and 10 dB at 3 MHz. And a maximum clearance of 28 dB at 2 MHz was achieved when 1.52 mW laser was illuminated. In addition, the photodetector showed excellent linearities for both DC and AC amplifications in the laser power range between 12.5 μW and 1.52 mW.

  13. Eigenvalue assignment by minimal state-feedback gain in LTI multivariable systems

    NASA Astrophysics Data System (ADS)

    Ataei, Mohammad; Enshaee, Ali

    2011-12-01

    In this article, an improved method for eigenvalue assignment via state feedback in the linear time-invariant multivariable systems is proposed. This method is based on elementary similarity operations, and involves mainly utilisation of vector companion forms, and thus is very simple and easy to implement on a digital computer. In addition to the controllable systems, the proposed method can be applied for the stabilisable ones and also systems with linearly dependent inputs. Moreover, two types of state-feedback gain matrices can be achieved by this method: (1) the numerical one, which is unique, and (2) the parametric one, in which its parameters are determined in order to achieve a gain matrix with minimum Frobenius norm. The numerical examples are presented to demonstrate the advantages of the proposed method.

  14. Do low-calorie sweeteners promote weight gain in rodents?

    PubMed

    Glendinning, John I

    2016-10-01

    Low-calorie sweeteners (LCSs) are used globally to increase the palatability of foods and beverages, without the calories of sugar. Recently, however, there have been claims that LCSs promote obesity. Here, I review the literature linking LCS consumption to elevated body weight in rodents. A recent systematic review found when the LCSs were presented in water or chow, only a minority of the studies reported elevated weight gain. In contrast, when the LCSs were presented in yogurt, the majority of the studies reported elevated weight gain. This review focuses on this latter subset of studies, and asks why the combination of LCSs and yogurt promoted weight gain. First, LCSs have been hypothesized to induce metabolic derangement because they uncouple sweet taste and calories. However, the available evidence indicates that the LCS-treated yogurts did not actually taste sweet to rats in the published studies. Without a sweet taste, the concerns about uncoupling sweet taste and calories would not be relevant. Second, in several studies, the LCS-treated yogurt increased weight gain without increasing caloric intake. This indicates that caloric intake alone cannot explain the elevated weight gain. Third, there is evidence that LCSs and yogurt can each alter the gut microbiota of rodents. Given recent work indicating that changes in gut microbiota can modulate body weight, it is possible that the combination of LCS and yogurt alters the gut microbiota in ways that promote weight gain. While this hypothesis remains speculative, it is consistent with the observed rodent data. In human studies, LCSs are usually presented in beverages. Based on the rodent work, it might be worthwhile to evaluate the impact of LCS-treated yogurt in humans.

  15. Emotional eating as a mediator between depression and weight gain.

    PubMed

    van Strien, Tatjana; Konttinen, Hanna; Homberg, Judith R; Engels, Rutger C M E; Winkens, Laura H H

    2016-05-01

    Depression is often associated with weight gain but underlying mechanisms are unclear. This study assessed whether three psychological eating styles (emotional eating, external eating and restrained eating) act as mediators between depression and weight gain. We used structural equation modelling to test the hypothesized mediation models in a sample of 298 fathers and 294 mothers by assessing self-reported eating styles (Dutch Eating Behavior Questionnaire), depressive feelings (Depressive Mood List) and body mass index (BMI) at baseline and BMI after five years. In the model with emotional eating we also assessed the moderation effect of 5-HTTLPR genotype in a sub-sample of 520 Caucasians. All analyses were performed separately for the two sexes. Although the overall effect of depression on weight gain was statistically non-significant in both sexes, there was a causal chain between depression, emotional eating and weight gain in the mothers. Depressive symptoms were related to higher emotional eating and emotional eating predicted greater increases in BMI independently of depression. Moreover, the indirect effect (via emotional eating) of depression on BMI change was significant (Beta = 0.18, P = 0.026). This mediation effect was found to be independent of 5-HTTLPR genotype. No such mediation effect was found for the fathers. Further, external eating and restrained eating did not act as mediators between depression and weight gain in either sex. The finding that emotional eating acted as mediator between depression and weight gain in the mothers suggests that obesity interventions should take emotional eating into account. PMID:26911261

  16. Gain Control Network Conditions in Early Sensory Coding

    PubMed Central

    Serrano, Eduardo; Nowotny, Thomas; Levi, Rafael; Smith, Brian H.; Huerta, Ramón

    2013-01-01

    Gain control is essential for the proper function of any sensory system. However, the precise mechanisms for achieving effective gain control in the brain are unknown. Based on our understanding of the existence and strength of connections in the insect olfactory system, we analyze the conditions that lead to controlled gain in a randomly connected network of excitatory and inhibitory neurons. We consider two scenarios for the variation of input into the system. In the first case, the intensity of the sensory input controls the input currents to a fixed proportion of neurons of the excitatory and inhibitory populations. In the second case, increasing intensity of the sensory stimulus will both, recruit an increasing number of neurons that receive input and change the input current that they receive. Using a mean field approximation for the network activity we derive relationships between the parameters of the network that ensure that the overall level of activity of the excitatory population remains unchanged for increasing intensity of the external stimulation. We find that, first, the main parameters that regulate network gain are the probabilities of connections from the inhibitory population to the excitatory population and of the connections within the inhibitory population. Second, we show that strict gain control is not achievable in a random network in the second case, when the input recruits an increasing number of neurons. Finally, we confirm that the gain control conditions derived from the mean field approximation are valid in simulations of firing rate models and Hodgkin-Huxley conductance based models. PMID:23874176

  17. Body Weight Gain during Altered Gravity: Spaceflight, Centrifugation and Transitions

    NASA Technical Reports Server (NTRS)

    Wade, Charles E.; Harper, J. S.; Daunton, N. G.; Corcoran, M. L.; Morey-Holton, E.; Hargens, Alan R. (Technical Monitor)

    1995-01-01

    Gravity is a force that influences all living systems, and is often disregarded in the study of environment on growth and development. To assess the effect of gravity exposure on growth, immature rats (130-200 g) were evaluated during chronic altered gravity exposure and during transition between gravity fields. The effects of 14 days of spaceflight on body weight gain were evaluated (n=12) and compared to controls. Spaceflight did not affect weight gain. In 6 rats, the transition from spaceflight to 1 G showed a significant (p less than 0.05) post flight weight loss over 48 hr of 13 g compared to controls. Over subsequent days this loss was compensated for with no difference noted after 5 days. Exposure to hypergravity, 2 G for 16 days, was evaluated in groups of n=6 (Control; On Center Control (OCC); Centrifuged). With centrifugation or OCC there was a reduction in body weight within 24 hr. The OCC regained control weights within 13 days. The weight difference, 26 +/- 1 g, persisted with 2 G with no subsequent difference in weight gain over days 3-16 compared to controls; 3.7 +/- 0.1 versus 3.9 +/- 0.1 g/day respectively. Transition from centrifugation to 1 G resulted in a weight increase within 48 hours. Over 16 days the rate of gain was increased 3.1 +/- 0.1 g/day for centrifuge compared to 2.1 +/- 0.1 g/day for controls between Day 3 to 16. However, differences from control were still noted on Day 16. Transition from one gravity field to another causes acute changes in body weight. Transition to microgravity or 1 G, following the acute changes, results in adjustments to attain a normal weight. In hypergravity the acute reduction in body weight persist, but weight gain is normal. Transitioning from hypergravity to 1G results in an increased weight gain to compensate for the persistent reduction during exposure.

  18. Evaluation of chromosome 1q gain in intracranial ependymomas.

    PubMed

    Rajeshwari, Madhu; Sharma, Mehar Chand; Kakkar, Aanchal; Nambirajan, Aruna; Suri, Vaishali; Sarkar, Chitra; Singh, Manmohan; Saran, Ravindra Kumar; Gupta, Rakesh Kumar

    2016-04-01

    Ependymomas are relatively uncommon gliomas with poor prognosis despite recent advances in neurooncology. Molecular pathogenesis of ependymomas is not extensively studied. Lack of correlation of histological grade with patient outcome has directed attention towards identification of molecular alterations as novel prognostic markers. Recently, 1q gain has emerged as a potential prognostic marker, associated with decreased survival, especially in posterior fossa, high grade tumors. Cases of intracranial ependymomas were retrieved. Tumors were graded using objective criteria to supplement WHO grading. Fluorescence in situ hybridization for 1q gain was performed on formalin-fixed paraffin embedded sections. Eighty-one intracranial ependymomas were analyzed. Pediatric (76%) and infratentorial (70%) ependymomas constituted the majority. 1q gain was seen in 27 cases (33%), was equally frequent in children (34%) and adults (32%), supratentorial (37%) and infratentorial (32%) location, grade II (33%) and III (25%) tumors. Recurrence was noted in 24 cases and death in 7 cases with 5-year progression-free and overall-survival rates of 37% and 80%, respectively. Grade II tumors had a better survival than grade III tumors; histopathological grade was the only prognostically significant marker. 1q gain had no prognostic significance. 1q gain is frequent in ependymomas in Indian patients, seen across all ages, sites and grades, and thus is likely an early event in pathogenesis. The prognostic value of 1q gain, remains uncertain, and multicentric pooling of data is required. A histopathological grading system using objective criteria correlates well with patient outcome and can serve as an economical option for prognostication of ependymomas. PMID:26725097

  19. Color Addition and Subtraction Apps

    ERIC Educational Resources Information Center

    Ruiz, Frances; Ruiz, Michael J.

    2015-01-01

    Color addition and subtraction apps in HTML5 have been developed for students as an online hands-on experience so that they can more easily master principles introduced through traditional classroom demonstrations. The evolution of the additive RGB color model is traced through the early IBM color adapters so that students can proceed step by step…

  20. Effective gain measurements in chromium-doped forsterite

    NASA Technical Reports Server (NTRS)

    Petricevic, V.; Seas, A.; Alfano, R. R.

    1991-01-01

    Effective gain cross section in tetravalent chromium-doped forsterite laser crystal was measured over the 1180-1330 nm spectral range. The experiment was performed using two collinear laser beams in a pump-and-probe arrangement. The peak-gain cross section from this measurement is estimated to be 1.9 x 10 to the -19th sq cm at 1215 nm, which is comparable to the value of about 2 x 10 to the -19th sq cm predicted by fluorescence linewidth and lifetime measurements. These results indicate that excited-state absorption is not a major loss mechanism in tetravalent chromium-doped forsterite.

  1. Gain-switched holmium-doped fibre laser.

    PubMed

    Wu, Ka S; Ottaway, David; Munch, Jesper; Lancaster, David G; Bennetts, Shayne; Jackson, Stuart D

    2009-11-01

    We demonstrate the first gain-switched, singly doped, single-mode holmium-doped silicate glass fibre laser that operates at 2.106 microm. Using a gain-switched 1.909-microm thulium-doped fibre laser as the pump source, output pulses of energy 3.2 microJ and pulse duration of 150 ns were generated at 80 kHz and slope efficiency of 44%. Pulse stacking within the holmium-doped fibre laser resulted in significantly shorter 70 ns pulses.

  2. Limits to the information gain from lidar measurements.

    PubMed

    Belmonte, Aniceto

    2015-04-15

    Measurements over the return signal are an integral part of lidar remote sensing by which we gather information about the characteristics of specific targets. But how much information is gained by performing a given lidar measurement? By defining Shannon's mutual information of a lidar observation, here we consider the bits of information content on the measurement and describe mathematically the capacity of lidar estimates to represent a corresponding property in the target. For heterodyne Doppler lidars in particular, we have found simple analytical formulas that consider the information gain in mean-frequency estimates.

  3. Digitally gain controlled linear high voltage amplifier for laboratory applications.

    PubMed

    Koçum, C

    2011-08-01

    The design of a digitally gain controlled high-voltage non-inverting bipolar linear amplifier is presented. This cost efficient and relatively simple circuit has stable operation range from dc to 90 kHz under the load of 10 kΩ and 39 pF. The amplifier can swing up to 360 V(pp) under these conditions and it has 2.5 μs rise time. The gain can be changed by the aid of JFETs. The amplifiers have been realized using a combination of operational amplifiers and high-voltage discrete bipolar junction transistors. The circuit details and performance characteristics are discussed.

  4. Gain calibration of a horn antenna using pattern integration

    NASA Technical Reports Server (NTRS)

    Ludwig, A. C.; Hardy, J.; Norman, R.

    1972-01-01

    Gain measurement of a horn antenna using three different techniques is discussed. The methods include a two-antenna insertion loss measurement, a pattern integration method, and a near-field measurement method. The application of the pattern integration method is considered, as well as the evaluation of the near-field gain correction factors for the horn, which are determined by a method based directly on measured data. This method involves a spherical wave expansion of the experimental radiation pattern of the specific antenna being tested, rather than evaluation of an assumed analytical model. The spherical wave expansion is also compared to experimental near-field pattern data.

  5. Overcoming losses with gain in a negative refractive index metamaterial.

    PubMed

    Wuestner, Sebastian; Pusch, Andreas; Tsakmakidis, Kosmas L; Hamm, Joachim M; Hess, Ortwin

    2010-09-17

    On the basis of a full-vectorial three-dimensional Maxwell-Bloch approach we investigate the possibility of using gain to overcome losses in a negative refractive index fishnet metamaterial. We show that appropriate placing of optically pumped laser dyes (gain) into the metamaterial structure results in a frequency band where the nonbianisotropic metamaterial becomes amplifying. In that region both the real and the imaginary part of the effective refractive index become simultaneously negative and the figure of merit diverges at two distinct frequency points.

  6. High gain multigap avalanche detectors for Cerenkov ring imaging

    SciTech Connect

    Gilmore, R.S.; Lavender, W.M.; Leith, D.W.G.S.; Williams, S.H.

    1980-10-01

    We report on a continuing study of multigap parallel plate avalanche chambers, primarily as photoelectron detectors for use with Cerenkov ring imaging counters. By suitable control of the fields in successive gaps and by introducing screens to reduce photon feedback to the cathode the gain many be increased considerably. We have obtained gains in excess of 6 x 10/sup 7/ for photoelectrons with a good pulse height spectrum and expect to increase this further. We discuss the use of resistive anodes to give avalanche positions in two dimensions by charge division.

  7. Une Introduction Non Classique aux Algorithmes d'Addition et de Soustraction (A Non-Classical Introduction to Algorithms of Addition and Subtraction).

    ERIC Educational Resources Information Center

    Arsenault, Cathy; Lemoyne, Gisele

    2000-01-01

    Analyzes a didactical sequence for the teaching of addition and subtraction procedures and algorithms. Uses didactical procedures by children in problem solving activities in order to gain a better understanding of the interaction between numbers, numeration, and operations knowledge which are involved in the construction of addition and…

  8. Color Addition and Subtraction Apps

    NASA Astrophysics Data System (ADS)

    Ruiz, Frances; Ruiz, Michael J.

    2015-10-01

    Color addition and subtraction apps in HTML5 have been developed for students as an online hands-on experience so that they can more easily master principles introduced through traditional classroom demonstrations. The evolution of the additive RGB color model is traced through the early IBM color adapters so that students can proceed step by step in understanding mathematical representations of RGB color. Finally, color addition and subtraction are presented for the X11 colors from web design to illustrate yet another real-life application of color mixing.

  9. Many-body effects on optical gain in GaAsPN/GaPN quantum well lasers for silicon integration

    SciTech Connect

    Park, Seoung-Hwan

    2014-02-14

    Many-body effects on the optical gain in GaAsPN/GaP QW structures were investigated by using the multiband effective-mass theory and the non-Markovian gain model with many-body effects. The free-carrier model shows that the optical gain peak slightly increases with increasing N composition. In addition, the QW structure with a larger As composition shows a larger optical gain than that with a smaller As composition. On the other hand, in the case of the many-body model, the optical gain peak decreases with increasing N composition. Also, the QW structure with a smaller As composition is observed to have a larger optical gain than that with a larger As composition. This can be explained by the fact that the QW structure with a smaller As or N composition shows a larger Coulomb enhancement effect than that with a larger As or N composition. This means that it is important to consider the many-body effect in obtaining guidelines for device design issues.

  10. Optimal Weight Gain During Pregnancy in Japanese Women

    PubMed Central

    Suzuki, Shunji

    2016-01-01

    Background In order to examine the optimal weight gain during pregnancy in Japanese women, we analyzed the perinatal outcomes in Japanese women with the optimal range of weight gain during pregnancy according to the Japanese (the Japanese Ministry of Health, Labour and Welfare: JMHLW and the Japan Society for the Study of Obesity: JASSO) guidelines compared with those according to the USA (the Institute of Medicine: IOM) guideline. Methods We compared the obstetric outcomes in two groups of gestational weight gain within the optimal range based on the IOM and Japanese guidelines in women of pre-pregnancy body mass index (BMI) categories of underweight, normal, overweight and obese. Results In the underweight and normal-weight women, the incidences of preterm delivery and low-birth-weight infant in the JMHLW group were significantly higher than those in the IOM group; however, the incidence of some other perinatal complications in the JMHLW group was significantly lower than that in the IOM group. In the overweight women, the incidences of preterm delivery and low-birth-weight infant in the JSSO group were significantly higher than those in the IOM group; however, there were no significant differences in the obstetric outcomes between the obese women in the JSSO and IOM groups. Conclusion Based on the current results, we should be more tolerant for the weight gain during pregnancy in Japanese woman than ever, especially in overweight women.

  11. Characterization of newly gained introns in Daphnia populations.

    PubMed

    Li, Wenli; Kuzoff, Robert; Wong, Chen Khuan; Tucker, Abraham; Lynch, Michael

    2014-08-14

    As one of the few known species in an active phase of intron proliferation, the microcrustacean Daphnia pulex is an especially attractive system for interrogating the gain and loss of introns in natural populations. In this study, we used a comparative population-genomic approach to identify and characterize 90 recently gained introns in this species. Molecular clock analyses indicate that these introns arose between 3.9 × 10(5) and 1.45 × 10(4) years ago, with a spike in intron proliferation approximately 5.2 × 10(4) to 1.22 × 10(5) years ago. Parallel gains at homologous positions contribute to 47.8% (43/90) of discovered new introns. A disproportionally large number of new introns were found in historically isolated populations in Oregon. Nonetheless, derived, intron-bearing alleles were also identified in a wide range of geographic locations, suggesting intron gain and, to a lesser degree, intron loss are important sources of genetic variation in natural populations of Daphnia. A majority (55/90 or 61.1%) of the identified neointrons have associated internal direct repeats with lengths and compositions that are unlikely to occur by chance, suggesting repeated bouts of staggered double-strand breaks (DSBs) during their evolution. Accordingly, internal, staggered DSBs may contribute to a passive trend toward increased length and sequence diversity in nascent introns.

  12. Interpersonal Attraction in Relation to the Loss-Gain Hypothesis.

    ERIC Educational Resources Information Center

    Sharma, Vandana; Kaur, Inderjeet

    1996-01-01

    Maintains that a loss-gain hypothesis (a negative impression gives way to a positive one) is a more powerful indicator and incentive for future friendship than an opposite sequence (positive to negative). Both of these, however, were eclipsed by a positive-positive interaction as a determinant of interpersonal attraction. (MJP)

  13. On Point Designs for High Gain Fast Ignition

    SciTech Connect

    Key, M; Akli, K; Beg, F; Betti, R; Clark, D S; Chen, S N; Freeman, R R; Hansen, S; Hatchett, S P; Hey, D; King, J A; Kemp, A J; Lasinski, B F; Langdon, B; Ma, T; MacKinnon, A J; Meyerhofer, D; Patel, P K; Pasley, J; Phillips, T; Stephens, R B; Stoeckl, C; Foord, M; Tabak, M; Theobald, W; Storm, M; Town, R J; Wilks, S C; VanWoerkom, L; Wei, M S; Weber, R; Zhang, B

    2007-09-27

    Fast ignition research has reached the stage where point designs are becoming crucial to the identification of key issues and the development of projects to demonstrate high gain fast ignition. The status of point designs for cone coupled electron fast ignition and some of the issues they highlight are discussed.

  14. Brain Gain 2010: Building Oklahoma through Intellectual Power.

    ERIC Educational Resources Information Center

    Oklahoma State Regents for Higher Education, Oklahoma City.

    The report discusses Brain Gain 2010, a strategic plan to increase the proportion of Oklahoma's population with college degrees. National figures show that states with the greatest economic success have the highest percentages of college-educated citizens. Currently, Oklahoma ranks in the bottom one-third of all states for the educational…

  15. Measuring Gains in Reading Ability with Passage Reading Fluency

    ERIC Educational Resources Information Center

    Jenkins, Joseph R.; Zumeta, Rebecca; Dupree, Opio; Kent Johnson

    2005-01-01

    This study examined several aspects of Passage Reading Fluency (PRF) including performance variability across passages alternative designs for measuring PRF gain, and effects on PRF level from retesting with the same passages. Participants were 33 students from grades 2 to 10 attending a school for students with learning disabilities. PRF was…

  16. Acoustics of fish shelters: frequency response and gain properties.

    PubMed

    Lugli, Marco

    2012-11-01

    Many teleosts emit sounds from cavities beneath stones and other types of submerged objects, yet the acoustical properties of fish shelters are virtually unexplored. This study examines the gain properties of shelters commonly used by Mediterranean gobies as hiding places and/or nest sites in the field (flat stones, shells belonging to five bivalve species), or within aquarium tanks (tunnel-shaped plastic covers, concrete blocks, concrete cylinder pipe, halves of terracotta flower pots). All shelters were acoustically stimulated using a small underwater buzzer, placed inside or around the shelter to mimic a fish calling from the nest site, and different types of driving stimuli (white noise, pure tones, and artificial pulse trains). Results showed the presence of significant amplitude gain (3-18 dB) at frequencies in the range 100-150 Hz in all types of natural shelters but one (Mytilus), terracotta flower pots, and concrete blocks. Gain was higher for stones and artificial shelters than for shells. Gain peak amplitude increased with the weight of stones and shells. Conclusions were verified by performing analogous acoustical tests on flat stones in the stream. Results draw attention to the use of suitable shelters for proper recording of sounds produced by fishes kept within laboratory aquaria.

  17. Clinical nurse specialists gain title protection in Pennsylvania.

    PubMed

    Duffy, Melanie

    2008-01-01

    Clinical nurse specialists (CNSs) in Pennsylvania will long remember the bright, sunny day of July 20, 2007. That was the day Governor Edward G. Rendell signed House Bill 1254 into law. Clinical nurse specialists in Pennsylvania finally gained title protection! What does this mean? How did it all come about? What are the implications for practice? PMID:18091127

  18. 75 FR 66708 - Program Integrity: Gainful Employment; Correction

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-29

    ...: On October 18, 2010, we published in the Federal Register (75 FR 63763) a notice announcing public... Program Integrity: Gainful Employment, published in the Federal Register on July 26, 2010 (75 FR 43616... rule FR Doc. 10-26180, beginning on page 67363 in the issue of October 18, 2010, make the...

  19. Flexible Contrast Gain Control in the Right Hemisphere

    ERIC Educational Resources Information Center

    Okubo, Matia; Nicholls, Michael E. R.

    2005-01-01

    This study investigates whether the right hemisphere has more flexible contrast gain control settings for the identification of spatial frequency. Right-handed participants identified 1 and 9 cycles per degree sinusoidal gratings presented either to the left visual field-right hemisphere (LVF-RH) or the right visual field-left hemisphere (RVF-LH).…

  20. High-Stakes Testing Hasn't Brought Education Gains

    ERIC Educational Resources Information Center

    Dianis, Judith Browne; Jackson, John H.; Noguera, Pedro

    2015-01-01

    The only thing that more testing will tell us is what we already know: The schools that disadvantaged children attend are not being given the supports necessary to produce achievement gains. Students cannot be tested out of poverty, and while NCLB did take us a step forward by requiring schools to produce evidence that students were learning, it…